Tuesday, April 29, 2008

Underground compressed air storage, geothermal power and radiation from radon

During the recent Oil Drum debate on Nuclear EROEI, "Cyril R." a frequent commenter on energy related blogs made a case for "Compressed Air Energy Storage" (CAES).

In a response to a comment concerning the low capacity factor for wind, "Cyril R." stated
"the capacity factor you referenced is very low, good locations in the US get 30-40%, which is close to the average capacity factor in the US. Moreover, consider the correlation with the load to be more indicative than capacity factor. Not good for wind, but with CAES this can be cost-effectively dealt with; the CAES equipment is similar to NG turbines, i.e. they have low materials input so this won't fundamentally increase the materials input for wind."

Cyril R proposed compressed air storage in salt domes and saline aquifers which he argued were adjacent to areas of high-quality wind resources.

My initial response was to observe:

"The last time I checked, the expansion of compressed gasses has a cooling effect. If the gases contain humidity the cooling can produce condensation and even freezing. The Grand Solar Scheme recognized the problem and proposed to burn natural gas in the released air stream to reheat it. There are two problems with this approach. First as we all know natural gas is not a sustainable resource, so it is not a sustainable solution. Secondly, burning natural gas produces CO2, and thus a CAES solution would contribute to global warming."

Cyril R. responded:

". . . using biomass derived fuel for heating in combination with hydrogen. In this instance, the use of hydrogen would be interesting because of the higher thermodynamic efficiency. In adittion, there is the AACAES approach which is hardly rocket science. Just add thermal oil storage (proven industrial technology) to store the heat created during the compression stages and use it later to deal with the cooling effect of expansion."

"Cyril R.'s" burning biomass suggestion is problematic from a number of views. The collection and transportation of large amounts of biomass would be energy intensive, the use of a technology involving the extraction of large amounts of heat from compressed air into mineral oil, and then the discharge of that heat into expanding air would be an added expense to a CAES system.

In addition to "Cyril R.'s" CAES scheme, the January Scientific American, published an article on a "A Grand Solar Plan" that proposed a CAES scheme involving caves.

Following the debate an interesting problem with the CAES system occurred to me. Any CAES project involving the release of compressed air from underground storage in salt domes and saline aquifers would probably transport radon to the surface.

Let us examine the problem. Radon is a colorless, chemically inert, radioactive gas produced by the radioactive decay of thorium and uranium in the earths crust, Because it is a gas radon can be drawn into the lungs. There it produces a radioactive multiple whammy. Radon 222, if it decays in the lungs, produces a long and deadly decay chain. (222Rn (3.82 days) → 218Po (3.1 min) → 218At (1.5 s) → 218Rn (35 ms) → 214Pb (26.8 min) → 214Bi (19.7 min) → 214Po (164 µs) → 210Pb (22.3 yr) → 210Bi (5.01 days) → 210Po (138 days) → 206Pb (stable). Each isotope in the chain releases more radiation into the lungs triggering more and more carsenogenic lung tissue damage. Radon is considered to be next to smoking the second leading cause of Lung cancer for Americans. Radon exposure greatly increases the lung cancer danger for smokers.

While salt domes generally contain virtually no radon, surrounding rock does. Critics of nuclear power have long argued that radioisotopes from "nuclear waste" placed in salt domes can be transported out of them through a variety of mechanisms. Similar mechanisms could transported radon from surrounding rocks into salt dome cavities used to store compressed air. The method of creation of salt dome cavities together with the effect of compressed air on the surrounding salt and rock might tend to open up channels for radon transport from radioactive rocks into the compressed air cavity. These would include the use of water to form the original cavity, the heat and humidity of the compressed air, together with the the effects of highly pressured air on the flaws and imperfections in the salt structure surrounding the cavity. All these forces could tend to open up transport channels between surrounding radioactive rocks, and the salt dome cavity. The fluxuating air pressure, caused by compression and decompression could pump the radon from the surrounding rock into the cavity. The release of compressed air from the cavity would force radon to the surface.

The use of saline aquifers for compressed air storage is even more problematic. A recent Geotimes report, "Rooting Out Radioactive Groundwater" focus on the problem of radon in all aquifers. It states:

"Groundwater from deep aquifers is typically oxygen-depleted and has a very slow flow rate, and marginal water typically has high salinity. These alternative water resources may therefore also have high radium concentrations."

Thus it would appear that significant atmospheric radon release associated with CAES energy storage in saline aquifers is very likely, and in the case of salt dome storage is quite possible.

The presence of radon in geothermal hot water and steam used in the generation of geothermal power has also been ignored, although high concentrations of radon could be expected from molten and hot rocks. Geothermal power techniques involved in the insertion of large amounts of water into hot sub surface rocks, would almost certainly lead to the transport of large amounts of radon to the surface with hot water and steam

Saturday, April 26, 2008

The benefits of LFTR's

(I posted this as a comment on Energy from Thorium this morning.)

1. The LFTR is an extremely safe reactor design. It is self regulating. Core meltdown is absolutely not a problem. Continuous removal of radioactive gases insure that only small amounts of radioactive gases would be released in a worst case accident. Coolant leaks do not lead to fires or explosions. There would be little or no solid fission product release/radiation problem in the event of a leak. Because of the chemical properties of the liquid salt coolant/fuel attacks by terrorists using explosives or aircraft, would not create a wide dispersal of radioactive materials. The use of liquid salts eliminating a threat to public safety from terrorists attack on LFTRs.

2. The thorium fuel cycle is efficient. Up to 98% of thorium used in a LFTR can be burned. In contrast only about 0.6% of uranium involved in the LWR/uranium fuel cycle is burned.

3. Virtual elimination f the problem of nuclear waste. The LFTR produces 0.1% of the waste that light water reactors produce, per unit of power produced. Instead, the spent fuel of LFTRs contains many useful and some rare and very valuable metals and minerals. LFTR "spent fuel" represents a potential means of providing industry with rare materials in an increasingly resource starved world.

4. Lowest fuel cycle costs coupled with very high fuel safety. A LFTR is more than a reactor. It is a fuel processing/reprocessing system. The liquid salts approach enables fuel and breeding materials to be processed on a continuous basis while the reactor is producing power. This includes continuous removal of gases produced in the nuclear reaction, the processing of newly breed reactor fuel, the removal of fission products. Nuclear fuel (U-233, U-235, and plutonium) can be continuously added to the reactor. Thus the reactor never needs to stop operating for refueling. The nature of the LFTR fuel cycle makes reactor fuel theft by terrorist impossible, while diversion of reactor fuel for weapons purposes a very unlikely approach to nuclear proliferation.

5. Lower manufacturing, construction and siting costs coupled with great manufacturing time efficiencies. The LFTR can be designed in a size that can be mass produced on assembly lines. Many external parts including heat exchanges can be made from low cost carbon-carbon composite materials, dramatically lowering materials, parts, and assembly costs. High reactor operating temperatures mean that electricity can be generated using low cost-highly efficient closed cycle gas turbines. Compact reactor/generation unit means smaller, less expensive reactor/power unit housing is required. The inherently safer design means that less money needs to be spent on reactor safety systems, and on accident containment, while assuring the highest possible public safety. Small reactor/power generator size can simplify siting problems LRTRs can be manufactured and set up in weeks or months, compared years for custom built LWRs.

6. Liquid core reactors can be used to dispose of existing stocks of nuclear waste..

Thursday, April 24, 2008

A response on EROEI and fuel cycle/reactor efficiency

A comment posted on Oil Drum today
A response on EROEI and fuel cycle/reactor efficiency

The entire business of EROEI studies is a diversion from the question of reactor efficiency. We know that vast amounts of energy are locked up in uranium and thorium. What we need to be doing is studying the efficiencies of fuel cycle/reactor systems in extracting that energy, rather than expending our time arguing about the EPOEI of one system. Any review of the uranium/light water reactor fuel cycle will review that it does an extremely poor job of extracting the potential energy of nuclear fuel.

EROEI studies never note the different between the energy economies of the CANDU reactor and the LWR. CANDU reactors have a demonstrated ability to operate with almost nuclear fuel including natural uranium. The EROEI of natural uranium CANDU fuel cycles should be examined. There are presently 18 CANDU reactors operating in Canada. Other CANDU reactors operate in India, China, Korea Argentine, and Romania. CANDU Reactors can be operated using "spent" nuclear fuel from LWR. The EROEI for recycled fuel would be very large, since recycled fuel would enter the CANDU with only the energy input of transportation and fuel fabrication. Tests have been run on CANDU reactors.

The Indians has just completed construction the Advanced Heavy Water Reactor (AHWR) a CANDU type reactor to run on thorium cycle fuel.

It is one of the most advanced reactors in the world, and should have an EROEI significantly better than the EROEI of Light Water Reactors. The Indians plan to embark on serial production of AHWR type reactors, before 2020.

A second reactor type whose EROEI should be examined, is the Russian BN-600. Although the BN-600 is a developmental LMFBR reactor that has successfully delivered commercial nuclear power since 1980. The Japanese have purchased BN-600 technology from the Russians, and may build duplicates.

Thirdly, the Indiana are engaged in a significant thorium fuel cycle. The Indians have already built and tested both thorium fuel cycle proof on concept and developmental thorium fuel cycle reactors and have built or are building prototype thorium fuel cycle reactors including the just completed AHWR, the soon to be completed Prototype Fast Breeder Reactor (PFBR) at Kalpakkam, and the more advanced , Fast Thorium Breeder Reactor (FTBR) underdevelopment at the Bhabha Atomic Research Centre in Mumbai.is second thorium fuel cycle breeder. The Indians are in the last stage of a 3 stage developmental program for a complex Uranium/thorium reactor fuel system, that is many times more energy efficient than the Uranium/light water reactor fuel system.

The Indians plans to build thorium fuel cycle reactor capable of producing 20 GWy of electrical energy by 2020, and to produces 30% of their electricity from thorium cycle reactors by 2050. Indian scientists calculate that the assurred thorium reserve of India is large enough to provide it with electrcity for 400 years. Given the extent of Indian thorium cycle reactor development, and future plans and EROEI of nuclear industry EROIE that ignores the Indian plans is at the very least incomplete.

Further, any discussion of nuclear EROEI ought to note that that real world LWR EROEI using MOX is much than the EROEI of normally fueled French LWRs. The use Pu-239 in nuclear weapons absorbed the original energy input into weapons fissionable materials. The energy input into recycled fuel (MOX) would equal the energy requirements for disassembling nuclear weapons, fabricating MOX, and transporting it to the reactor. Reactor grade Plutionium can also be a source of MOX. U-238 in the MOX can be assummed to come from Depleted uranium stockpiles.

American civilian power reactors are being used to dispose of surplus Russian U-235. Fully half half of the uranium used in American reactors USA is ex-Russian military U-235. One sixth of the current world U-235 supply comes from recycling Russian nuclear weapons. In addition, Pu-239 from American and Russian nuclear weapon stockpiles, not ony can but should be used as reactor fuel.

The estimated US U-235 stockpile was estimated to be in the range of 750 tons in the early 1990s, of which 174 tons (23% of the total) have been declared surplus.[13] More than 30 tons of the excess HEU has been blended down, reducing the total stockpile to something in the range of 720 tons. The US has a plutonium of 111.4 tons. The UK acknowledges possession of a military stockpile of 7.6 tons of plutonium, 21.9 tons of HEU (U-235). The Japanese hold a plutonium stockpile of from 16 to 20 tons. In 2000 the US and Russia agreed to each dispose of 34 tons of weapons-grade plutonium. Estimates of the total world stockpile of weapons grade plutonium range as high as 300 tons.

In addition to surplus stockpiles of reactor grade plutonium, mostly found in "spent nuclear fuel" equals 400 tons. http://www.dhushara.com/book/explod/nuclears/pluteu.htm Civilian plutonium stockpiles are growing and constitute the largest single problem associated with "nuclear waste." But even if all civilian reactors shut down, the disposal of military and civilian plutonium would be a significant problem. By far the best solution from an EROEI viewpoint would be to burn the plutonium in breeder reactors or thorium converters as the Indians plan to do.

EROEI studies of nuclear power commit numerous other EROEI errors.

EROEi calculations do not evaluating reactor grade plutonium reprocessing in the UK, France and Germany, despite the fact that reactor grade plutonium returned to reactors amounts to largely free energy. http://www.inesap.org/bulletin16/bul16art15.htm

Various sources describe the amount of fissionable material remaining in “spent” nuclear fuel. The Wikipedia reports that 1% of the fuel mass of “spent fuel” is reactor grade plutonium. While unburned U-235 would constitute >.83 percent of the "spent" fuel mass. The Wikipedia also reports, “Fissile component starts at 0.71% 235U concentration in natural uranium). At discharge, total fissile component is still 0.50% (0.23% 235U, 0.27% fissile 239Pu, 241Pu).”

Plutonium based fuel can be used in Heavy Water Reactors.

With Heavy Water Reactors a burnup rate of 50% of reactor grade plutonium is possible with the use of a U-238 fuel cycle, and 75% with the use of a Th-232 fuel cycle.

The encyclopedia of the earth reports

Reactor grade plutonium contains about 55-70% of fissile Pu-239, and >19% of non-fissile Pu-240, non fissile isotopes of Plutonium will never constitute more 30% of reactor grade plutonium.

In contrast. studies of the use of ex-nuclear weapon Pu-239 in MOX fueled light water reactors suggest that only a net burnup on only 1/3 of the original plutonium, leaving an unsatisfactory burn is disposal of plutonium.

Depleted Uranium contains 0.25-0.30% U-235. http://www.world-nuclear.org/info/inf14.html
Thus the Uranium enrichment process looses 35% to 42% of the U-235 in natural uranium. 20% of reactor fuel U-235 fails to fission after absorbing reactor neutrons, thus becoming non-fissile U-236. (WASH-1097) Another 25%+ of reactor U-235 remains when the fuel will no longer support a chain reaction. In addition, plutonium remaining in the reactor amounts to nearly 25% of the original U-235 in the fuel charge. Thus the net fissile burnup rate in a light water reactor is only 30% of the original U-235 charge.
In contrast CANDU reactors contain about 0.2% U-235.

An equal amount of spent CANDU fuel will be PU-239. Hence Heavy Water Reactor fuel post-reactor fuel is more truly spent, while spent light water reactor fuel, contains more fissile material than natural uranium a fuel that can be used in Heavy Water Reactors.

Heavy Water reactors are also more efficient in burning U-235. Assuming 0.1% U236 content in "spent fuel" (WASH-1097), this means that 57% of the U-235 in natural uranium gets burned up heavy water reactors, verses a burnup of around 35% of the U-235 in natural uranium for light water reactors.

Since part or most of the nuclear energy of uranium and plutonium in post reactor LWR nuclear fuel is capturable by other reactors, it should be added to the energy output of light water reactors in a fair assessment of the uranium.LWR guel cycle..

Various sources describe the amount of fissionable material remaining in “spent” nuclear fuel. The Wikipedia reports that 1% of the fuel mass of spent fuel is reactor grade plutonium. While U-235 would constitute >.83 percent of the fuel mass. The Wikipedia also reports, “Fissile component starts at 0.71% 235U concentration in natural uranium). At discharge, total fissile component is still 0.50% (0.23% 235U, 0.27% fissile 239Pu, 241Pu).”

Plutonium based fuel can be used in Heavy Water Reactors.

With Heavy Water Reactors a burnup rate of 50% of reactor grade plutonium is possible with the use of a U-238 fuel cycle, and 75% with the use of a Th-232 fuel cycle.

The encyclopedia of the earth reports

Reactor grade plutonium contains about 55-70% of fissile Pu-239, and >19% of non-fissile Pu-240, non fissile isotopes of Plutonium will never constitute more 30% of reactor grade plutonium.

One Kg of fissile Plutonium burned in a reactor produces 10 MWh of electrical power. Thus one ton of fissile plutonium will produce 1 GW years of electrical power.

Studies of the use of nuclear weapon Pu-239 in MOX fueled light water reactors suggest that only a net burnup on only 1/3 of the original plutonium, leaving an unsatisfactory burn is disposal of plutonium.

Depleted Uranium contains 0.25-0.30% U-235. http://www.world-nuclear.org/info/inf14.html
Thus the Uranium enrichment process looses 35% to 42% of the U-235 in natural uranium. 20% of reactor fuel U-235 fails to fission after absorbing reactor neutrons, thus becoming non-fissile U-236. (WASH-1097) Another 25%+ of reactor U-235 remains when the fuel will no longer support a chain reaction. In addition, plutonium remaining in the reactor amounts to nearly 25% of the original U-235 in the fuel charge. Thus the net fissile burnup rate in a light water reactor is only 30% of the original U-235 charge.
In contrast CANDU reactors contain about 0.2% U-235.
An equal amount of spent CANDU fuel will be PU-239. Hence Heavy water reactor fuel is truly spent, while spent light water reactor fuel, contains more Fissile material than ordinary Heavy Water Reactor fuel does.

Assuming 0.1% U236 content (WASH-1097), this means that 57% of the U-235 in natural uranium gets burned up heavy water reactors, verses a burnup of around 35% of the U-235 in natural uranium for light water reactors.

Such great inefficiency leaves a great deal of nuclear fuel unused by light water reactors, but re-enrichment of so called "depleted uranium tailings" is currently being conducted at Paducah,
and in Russia.
And research continuses on improving the burnup ratio of LWRs.

In short some of the inefficiencies of the uranium/light water reactor fuel cycle are either being corrected or are amenable to correction. Nuclear EROEI is a snapshot in time, that often ignore the complexity of nuclear fuel cycles, as well as the effect of reactor, enrichment and fuel recovery technologies on nuclear fuel efficiency. Since it is impossible to generate a single number in calculations involving so many independent variables, the value of nuclear EROEI studies which arrives at a single number is very questionable, and a meta-analysis of such studies will lead to a distorted and inaccurate picture. The best we should hope for is a range of EROEI numbers for a given fuel cycle, with the possibility of a comparison between the ranges of various fuel/reactor options.

Monday, April 21, 2008

K. Z. Morgan, the Angry Genie of ORNL

My father, C.J. Barton, Sr., took temporary refuage in K. Z. Morgan's Health Physics devision as the ORNL Reactor Chemistry Division fell apart in the late 1960's. Although both his previous Division Director, Warren Grimes and his future Division Director, Ed Struxness play roles in my father's story about his ORNL career, Karl Z. Morgan, the Director of the Health Physics Division played no role in my father's history. This is remarkable because Morgan was almost legendary. My father's stay in the Health Physics division coincided with what were probably the most tumultuous times in the history of ORNL. I have elsewhere noted the factors that contributed to the chaos. The war in Vietnam, and the Apollo Moon program drained money away from nuclear research. Super AEC Bureaucrat, Milton Shaw was attempting to shut down nuclear safety research, and to channel reactor development towards the difficult project of making a LMFB work on commercial scale.

During the late 60's and early 70's ORNL;s staff was cut from 5500 to 3800, Weinberg struggled to save the lab by focusing on non-nuclear sources of funding. The changes effected every one. Some divisions, hard hit by funding cuts, were dissolved. Assignments were switched among divisions. A new division, the Environmental Studies Division was to emerge from the Health Physics Division. Compared to Warren Grimes, who had lost a Division, K.Z. Morgan did well.

The Introduction of the Department of Energy's oral history interview with K.Z. Morgan records a brief biography.:

"Dr. Morgan was born in Enochsville, North Carolina on September 27, 1907. He attended Lenoir-Rhyne College (Hickory, North Carolina), received B.S. and M.S. degrees (in Physics and Mathematics) in 1929 and 1930, respectively, from the University of North Carolina, and received his Ph.D. (Cosmic Radiation) in 1934 from Duke University (Durham, North Carolina). He is married and has four grown children.

Dr. Morgan began his career as a physics professor at Lenoir-Rhyne College (1934–1943), where he focused his work on cosmic ray research. In 1943, Dr. Morgan moved to Chicago to become a senior scientist in health physics for the Manhattan Engineer District. The following year, Dr. Morgan went to the newly formed Oak Ridge National Laboratory (formerly Clinton Laboratories) in Oak Ridge, Tennessee, where he served as Director of Health Physics from 1944 to 1972.

Since joining ORNL, Dr. Morgan has also held the following positions:

1945 to '71—Member, International Commission on Radiological Protection (ICRP)
1955 to '78—Member, National Council on Radiation Protection (NCRP)
1955 to '78—Editor-in-Chief, Health Physics Journal
1960 to '72—Adjunct Professor of Health Physics, Vanderbilt University
1972 to '83—Professor of Health Physics, Georgia Institute of Technology
1983 to '86—Visiting Professor of Health Physics, Appalachian State University (Boone, North Carolina).

This is the bare outline of Morgan's career.  Morgan's New York Times obituary described him as having been for "decades . . .  a pillar of the nuclear establishment", also stated: 

At midcentury, Dr. Morgan was a proponent of the near-Messianic view of nuclear science that then prevailed.

''We believe that the nuclear age is here to stay and that its future rests in large measure on the successful control of radiation exposure,'' he wrote in an editorial in the first issue of Health Physics.

''We must understand the full and ultimate consequences of this exposure and limit it at a level where we, and those that come after us, can reap the maximum benefits of this new age."

Later Morgan changed his views drastically.

The Times obituary also notes Morgan's autobiography, ''The Angry Genie: One Man's Walk Through the Nuclear Age.'' Ken M. Peterson, a civil litigator co-authored the book. By all accounts it is a well written, entertaining book, but it undoubtedly should be read with caution. Morgan had some very large axes to grind, and civil litigator know how to put the best face on the story of someone with a grievance.

In a review of ''The Angry Genie", Milton Terris recounted on of Morgan's stories which partially accounts for Morgan's disillusion:

Of particular interest is a chapter titled "My Biggest Mistake." Morgan was increasingly concerned about the newly developed liquid metal fast breeder reactor (LMFBR). He was convinced that the molten salt thermal breeder (MSTB), that had been developed at Oak Ridge National Laboratory (ORNL), provided a safer and more acceptable means of producing nuclear power.

In July 1971, Morgan arranged to deliver a paper on the dangers of the LMFBR at an international meeting of radiation physicists. He intended to express his view that the LMFBR offered a relatively easy means of access to an atomic bomb and that he much preferred the MSTB. "It was frightening to think of tons of plutonium as spent fuel from reactors being shipped through New York and other big cities to processing plants, then to fuel fabrication facilities, and finally back to LMFBRs all over the world."

He pointed out that plutonium-239 served as the operating fuel in the LMFBR and would be bred in relatively large concentrations in the natural uranium, 11-238. By means of a relatively simple procedure one could separate the plutonium and construct a low-level atomic bomb. The plutonium-239 produced by the LMFBR would not only serve as an incitement to terrorists, it also used plutonium, one of the greatest hazards of all radioactive materials.

MSTB, using U-233, held much less appeal for terrorists since it is very difficult to produce. Also, it can be denatured and rendered unsuitable for use in bombs. For this and other reasons, he considered MSTB to be preferable.

Morgan sent 250 copies of his paper to the meeting chairman. But in his absence on vacation, the decision was made to destroy his 250 copies and substitute a revised version. He was instructed to say nothing about the superiority of the MSTB over the LMFBR. He was told that "the president has decided to allocate $30 million of extra money to expedite building a demonstration LMFBR. You are jeopardizing the welfare of the laboratory." It was implied that if Morgan gave the original speech, hundreds of Oak Ridge jobs would be lost.

Morgan then states: "Here, I made the biggest mistake of my life. I reasoned that if I fought the issue and hundreds of people in Oak Ridge lost their jobs, I would be one of them-I would lose not only my job, but also the retirement benefits I had labored over a quarter of a century to obtain. I feared that powerful elements within ORNL management would destroy my reputation in the scientific community. . . . Red-faced, I bowed my head and described the risks of plutonium exposure, but without mentioning the MSTB or the LMFBR." When I returned to ORNL, my fellow employees, disgusted with management, deplored the incident. W. S. Snyder, my assistant director, said it constituted censorship. Snyder was right. I should have stood my ground regardless of the consequences. Had I done so, perhaps the world would never have had reactors such as those at Chernobyl and Three Mile Island."

Waldo Cohn, nuclear and genetic pioneer

Waldo Cohn was both a remarkable scientist and a remarkable person. I have previously posted about his leadership in the school desegregation controversy in Oak Ridge, which lead to the peaceful desegregation of Oak Ridge Schools in 1955. Waldo's was a biochemist, but pioneering physical chemical research on plutonium during World War II made an important contribution of nuclear technology. The ion exchange method Cohn developed had wide applications including the processing of fission products, rare earth separation, and in nucleic acid research.
In 1963, the American Chemical Society honored Cohn for his "pioneering work in ion exchange chromatography which has made possible much of the progress that has been made in two completely different fields of chemistry since World War II."

Dr. Cohn pioneered the use of radioisotopes as tracers in medicine and was influential in starting the production of radioisotopes for scientific research and medicine at Oak Ridge. He set up a system for radioisotope distribution.pioneered the use of radioisotopes in medicine.

He applied his plutonium research methods to the study of the components of the nucleic acids DNA and RNA, and his research made a major contribution to the understanding information transfer from nucleic acids to protein molecules.

Alvin Weinberg stated about his long time friend Waldo Cohn:

"The main task (in 1943) was to produce gram quantities of the nuclear explosive, plutonium. The techniques developed there were transferred to the huge plutonium-producing nuclear reactors at Hanford, Wash.

"To manufacture plutonium, one had to 'cook' uranium in an atmosphere of neutrons in the nuclear reactor at Clinton Lab. In this process uranium atoms were split to create radioactive 'fission products.' Cohn set about to identify the chemical species of fission products. He applied to this process a technique known as 'ion exchange chromotography.'

"After the war Cohn realized that this technique could be applied to the characterization of the components of the nucleic acids, DNA and RNA. Cohn's technique ultimately led to Crick and Watson's structure of the genetic materials, DNA and RNA. For this achievement Cohn received the Chromotography Award of the American Chemical Society and he was named a fellow of the American Academy of Arts and Sciences.

"Cohn was also the first to organize and promote the use of radioactive radioisotopes produced in nuclear reactors. The widespread use of radioisotopes is perhaps the most important scientific byproduct of the Manhattan Project."

Dr. Cohn's obituary in the Oak Ridger noted his many civic, artistic and political contributions to the Oak Ridge community:

"Cohn was politically involved both nationally and locally. He was one of the organizers of a petition signed by a large number of scientists urging that a nuclear bomb first be detonated in a test blast before being used on human targets. Immediately after World War II he became active in urging international control of nuclear weapons."

"Locally he was one of the leaders of a group of local Democrats who worked to make basic reforms in the organization and operation of the party in Anderson County."

"He was a strong proponent of the development of nuclear power and often spoke out against what he thought were exaggerated fears about the dangers of radioactive materials to the public. , , ,"

"Less than two months after joining the staff at Clinton Laboratories, he placed a small notice in The Oak Ridge Journal, weekly newspaper published by the Manhattan Engineer District, inviting all Oak Ridgers interested in playing in an orchestra to a meeting. Nine other musicians responded, two other strings and seven woodwind players. In a 1983 interview he told Juanita Glenn of The Knoxville News-Sentinel, "I didn't want to join an orchestra, I was just looking for someone to play duets."

"Cohn had studied the cello since age 11, although at first he hated carrying the large instrument. Before his 16th birthday he had been invited to join the Berkeley Community Orchestra."

"That initial group of interested early Oak Ridge musicians grew into a string orchestra of 19. At first they rehearsed in the Cohn living room but soon moved to the auditorium of the original Oak Ridge High School, which was located on the knoll off Kentucky Avenue overlooking Blankenship Field and which, before it was demolished, had become Jefferson Junior High School."

"The early musician group named him their conductor and gave their first concert as the Oak Ridge Symphonette in June 1944. Then, within weeks, they became the 65-member Oak Ridge Symphony, which gave its first concerts on Nov. 3-4, 1944."

"Besides the Symphony and his service on the early Advisory Town Council, Cohn was a regular reader for Recording for the Blind and Dyslexic, reading primarily scientific texts. In more recent years he also volunteered regularly at the Oak Ridge Convention and Visitors Bureau, where he would answer visitors' questions about the wartime atomic bomb development and the later research at the ORNL Biology Division, from which he had retired in 1975."

Waldo stepped down as conductor of the Oak Ridge Symphony in 1955 when he received the first of his two Guggenheim Fellowships, this was for a year's study at Cambridge University in England. Dr. Cohn also received a Fulbright Research Scholarship.

Cohn continued to play the cello in the Oak Ridge Symphony until ill health forced him to stop a couple of years before his death in 1999.

I had a brief visit with Cohn about 1998, because I wanted to capture his memories of his 1954 recall election from Oak Ridge City Council. He was by then in poor health, but his stories of the recall period were lively and illuminating. Cohn was very charismatic. He was handsome, and had an air of distinction about him.

Waldo Cohn, an Oral History

Oral History of Biochemist
Waldo E. Cohn, Ph.D.
Conducted January 18, 1995


In December 1993, U.S. Secretary of Energy Hazel R. O'Leary announced her Openness Initiative. As part of this initiative, the Department of Energy undertook an effort to identify and catalog historical documents on radiation experiments that had used human subjects. The Office of Human Radiation Experiments coordinated the Department's search for records about these experiments. An enormous volume of historical records has been located. Many of these records were disorganized; often poorly cataloged, if at all; and scattered across the country in holding areas, archives, and records centers.

The Department has produced a roadmap to the large universe of pertinent information: Human Radiation Experiments: The Department of Energy Roadmap to the Story and the Records (DOE/EH-0445, February 1995). The collected documents are also accessible through the Internet World Wide Web under http://www.hss.energy.gov/healthsafety/ohre/. The passage of time, the state of existing records, and the fact that some decisionmaking processes were never documented in written form, caused the Department to consider other means to supplement the documentary record.

In September 1994, the Office of Human Radiation Experiments, in collaboration with Lawrence Berkeley Laboratory, began an oral history project to fulfill this goal. The project involved interviewing researchers and others with firsthand knowledge of either the human radiation experimentation that occurred during the Cold War or the institutional context in which such experimentation took place. The purpose of this project was to enrich the documentary record, provide missing information, and allow the researchers an opportunity to provide their perspective.

Thirty audiotaped interviews were conducted from September 1994 through January 1995. Interviewees were permitted to review the transcripts of their oral histories. Their comments were incorporated into the final version of the transcript if those comments supplemented, clarified, or corrected the contents of the interviews.

The Department of Energy is grateful to the scientists and researchers who agreed to participate in this project, many of whom were pioneers in the development of nuclear medicine.


The opinions expressed by the interviewee are his own and do not necessarily reflect those of the U.S. Department of Energy. The Department neither endorses nor disagrees with such views. Moreover, the Department of Energy makes no representations as to the accuracy or completeness of the informa-tion provided by the interviewee.


Conducted on January 18, 1995, in Oak Ridge, Tennessee, by Thomas Fisher, Jr. and Michael Yuffee from the Office of Human Radiation Experiments, U. S. Department of Energy.

Waldo E. Cohn was selected for the oral history project because of his early research at the Oak Ridge National Laboratory, where he investigated the radiotoxicity of fission products; his role as the architect of this country's postwar isotope production and distribution policy; and his work developing a technique—ion-exchange chromatography—that has proved invaluable in the study of nucleic acids and other areas. The oral history primarily covers Dr. Cohn's early involvement with the Manhattan Project, including his work as the Biochemistry Group leader at the University of Chicago's Metallurgical Laboratory and his tenure at Oak Ridge National Laboratory, where he was a senior biochemist in the Biology Division.

Short Biography

Dr. Cohn was born in San Francisco, California, on June 28, 1910. He received his B.S. in 1931, his M.S. in Chemistry in 1932, and his Ph.D. in Biochemistry in 1938, all from the University of California, Berkeley. His graduate research involved the use of cyclotron-produced radioisotopes, and was thus among the first investigations in the U.S. to use these materials as tracers in uncovering metabolic and physiological processes. He has been married twice and has two children.

Dr. Cohn began his career as a teaching and research assistant in Biochemistry at Berkeley (1937–39). From 1939 to 1942, Dr. Cohn continued his research at Harvard Medical School. In 1942, Dr. Cohn was appointed Section Chief, Chemistry Division, of the Metallurgical Laboratory at the University of Chicago, where he stayed one year before moving to Oak Ridge. In 1947, Dr. Cohn became Senior Chemist and Group Leader of the Biology Division at Oak Ridge, a position he held until his retirement in 1975. While at Oak Ridge, Dr. Cohn has held the following positions:

1955 to 1956—Fulbright Scholar, Cambridge University;
1955 to 1956, 1962 to 1963—Guggenheim Fellow;
1959 to 1964—Treasurer, American Society of Biological Chemists;
1963—Visiting Professor, Institut de Biologie, Paris, France;
1965 to 1976—Secretary, Commission on Biochemical Nomenclature, International Union of Pure & Applied Chemists/International Union of Biochemists;
1965 to 1976—Director, Office of Biochemical Nomenclature, National Academy of Sciences; and
1966—Visiting Professor, Rockefeller University, New York, New York.
Dr. Cohn has published many times on artificial radioisotopes in biological systems; the isolation of individual fission-product species; and, especially, the development of a technique—elution chromatography on ion exchangers—that has proved invaluable in the study of nucleic acids. The techniques invented by Dr. Cohn in this field are now in use in the vast majority of biochemical and chemical laboratories and in chemical manufacture.

Recruited for the Metallurgical Laboratory (1943)

YUFFEE: My name is Michael Yuffee. I work for the Department of Energy, in the Office of Human Radiation Experiments. I'm here with Tom Fisher, also from the Office of Human Radiation Experiments. We're at the home of Waldo Cohn in Oak Ridge, Tennessee. It is January 18, 1995.

Dr. Cohn, I was wondering if we could start by going through a little bit of your background, your education, and where you're from to get us started, before we start talking about your days in the pioneering age of nuclear science.
COHN: I'm a graduate of University of California, Berkeley. I have a Master's [(M.S.) in Chemistry] and a Ph.D. in Biochemistry (1938). In 1939, I went to Harvard Medical School on a postdoctoral fellowship. I spent almost four years there, in the Huntington Memorial Laboratories of the Harvard Medical School and as a tutor in the Department of Biochemical Sciences at Harvard University. While I was there, I was solicited to join what turned out to be the Manhattan Project.1

I have to back up a minute and say that my Ph.D. thesis was done with artificial radioactive isotopes from [Ernest O.] Lawrence's cyclotron2 at Berkeley. I was one of the few people in the country at that time that had experience with artificial radioactive isotopes as tracers3 in biochemical and biological experiments. That's the reason I was sought out while I was still at Harvard and asked to join the [Manhattan] Project. They didn't tell me what the project was all about, except that my expertise was needed.
YUFFEE: What year was that?
COHN: In late 1942. In 1943, I went to Chicago and joined the Metallurgical Laboratory4 at the University [of Chicago], which was the code name for the plutonium project under Arthur Compton. That project was to investigate the biological and biochemical hazards that might be induced by the fission products that would result from a chain reactor, if one could ever be built. Of course, this is all a prelude to producing plutonium for an atomic bomb—again, if it could be made. So, I was more or less in charge of what I called radiobiological aspects of the plutonium project.
YUFFEE: At this point in time, you had already been aware of the first nuclear chain reaction?5
COHN: I became aware of it when I joined the project in Chicago, somewhere about February 1, 1943. I was not told, when they were soliciting me to join the project, what it was all about, but when I arrived there my supervisor told me all about it. So, [in] one day, I learned the whole basis of the thing—uranium-235,6 plutonium-239,7 and so forth.
YUFFEE: How did you originally become interested in biochemistry and chemistry? Was it just an interest you developed while you were in school?
COHN: I drifted. I was pretty good at chemistry and physics in high school. When I went to college, my advisor there saw four years of French on my [high school] report card [and] said, "You will major in French!" But, when I went home, my father said, "You march right back there and tell them that you will major in Chemistry!" So I became a chemist more [or] less by drifting.
FISHER: Who made the initial overtures to you about the joining the Met Lab?
COHN: People that I had been associated with [at] Berkeley around the cyclotron, Joseph Hamilton and John Lawrence (who was Ernest Lawrence's brother and who was a physician; maybe some others). They were the first ones [whom] the heads of the project sought out. The reason they were sought out was that the head of the whole biological and medical wing of the Manhattan Project at that time was Robert Stone, who was professor of Radiology at the University of California [Medical School]. He knew those people, and they knew of me, and they didn't want to be separated from what they were doing because they were all involved with Lawrence's part of the Manhattan Project, so they said, "Why don't we get this guy Cohn at Harvard?"

The upshot of it was that James Bryant Conant, who was the head of the Office of Scientific Research and Development,8 wrote a letter to James Bryant Conant, President of Harvard University, asking whether Waldo Cohn, working as a postdoc at the Harvard Medical School, could be spared. My boss asked me if I could [be] spared for an important war project, and I said, "Whatever you think." He told James Bryant Conant, President of Harvard, who wrote to James Bryant Conant, the head of OSRD, and said, "Yes, Waldo Cohn could be spared!"
FISHER: Remarkably simple process.

COHN: Yes, I thought that would amuse you, that [Conant] was wearing two hats.
FISHER: A lot of people wore two hats back in those days.
COHN: So, anyway, my boss didn't want me to leave, but he figured the war project was more important. I have a letter from the Harvard Board of Trustees giving me leave of absence for the war effort in 1942, but it wasn't until [February] 1943 that I actually joined.
YUFFEE: When you got to Chicago and to the Met Lab, what research did you do in terms of trying to find out biological—
COHN: —The first thing was to get our hands on some fission products, because this was going to be a laboratory investigation. I was a laboratory person; I wasn't just going around interviewing people. I had to set up a laboratory, and then, hopefully, we could get some fission products to experiment with and put them into animals and see how dangerous they were.
YUFFEE: What type of research were you doing with the animals in terms of trying to figure out biological and biochemical hazards?
COHN: This was all [only] planned, because there wasn't a going reactor. There was no plutonium; there were no fission products. This was all on paper.

The first thing I had to do was set up a laboratory and be prepared for when there would be fission products to work [with]. In the meantime, the project as a whole was devoted to building the graphite reactor at Oak Ridge[, Tennessee]. I guess it was still in the process of being built [because] it hadn't started operating yet.

The [plan] was that each one of us at Chicago would double the size of our group, from the top to the bottom, and half would go to Oak Ridge, when the reactor would be going, and half would remain at Chicago. I elected to go to Oak Ridge, where we would actually prepare the fission products and send them back to the half I would leave at Chicago, [where] they would do the biological experimentation. So, I became a nuclear chemist involved with isolating the fission products from the exposed uranium.
YUFFEE: And then you would send the products back to—
COHN: —Chicago for the biological experiments.
YUFFEE: And who was carrying those out in Chicago?
COHN: I think my second-in-command was [Ray] Finkle.
YUFFEE: Would these biological experiments be done with animals?
COHN: Yes.
YUFFEE: Were there ever any human subjects used?
COHN: No. That's what I said over the phone; that tying me in with human experimentation is misleading. It's true that some of the radioisotopes were [later] used as tracers in humans. However, there is an enormous difference between a tracer dose and a therapeutic dose—factors of a million or more.
FISHER: Can you explain that more? Can you elaborate on that fine point?
COHN: Well, you're aware of the concept of tracers; where you put a small amount of a radioactive substance in that will mimic the movements of a nonradioactive [substance]. For example, if you want to follow phosphorus in a water stream, you might want to put in radioactive phosphorus at one point, and at another point analyze the water for radioactive phosphorus. You can't just analyze [for] phosphorus, because it is always flowing [by]. [The] radioactive material you put in [is called] a tracer. It's as if you put in a red dye at one point and then look for red dye at the other point, there being no red dye in the stream that you are talking about.

The same is true with metabolic pathways in the animal body. If you want to know how sodium was behaving in the bloodstream, how fast it goes from one point to another, you would put in radioactive sodium at one point, take a sample of blood at another point, and measure how much is there and low long it took it to get there. That gives you an idea of sodium transport, or it could be phosphorus transport.

The metabolism of things in a mammalian body is very complex; we call it biochemistry. The whole science of biochemistry has profited by the use of radioactive tracers—carbon-14, tritium,9 radioactive phosphorus, radioactive calcium, radioactive sulfur—all [enable us] to trace the metabolic routes of things that [exist] in the body. That was the kind of work I did as graduate student; that's what I envisioned I'd be doing on the project.
Isolating Fission Products at Wartime Oak Ridge

COHN: But to get back to this business of the fission products, no one had been isolating them. It wasn't even known how many there were, or what their properties were. So, I became a nuclear chemist, involved with exploring how to get the fission products so they could be used as tracers in experiments; to see how they behaved in mammals. For example, whether they congregated in a certain place; whether radioactive strontium, if we could ever get our hands on it, would localize in a certain place. We know now that it does: it localizes in bone. This was the view of things at the time.

However, my work at Oak Ridge was not concerned with animals, even though the group I left in Chicago was. We, [at Oak Ridge], were concerned with how to isolate the fission products, one from the other, so they could be used in tracer and metabolic experiments at Chicago. I became a nuclear chemist rather than a biochemist, which was my training.
FISHER: In fact, you actually headed up the Radioactive Chemistry Division. That was your title?
COHN: I was originally part of the Health Division, which had several parts. One of them was my experimental part; the other was a radiological part; another was just taking care of the health of the workers. So, I don't know what they called my group. It might have been the Radiobiological Group.
FISHER: And you worked under Kenneth Cole?
COHN: In Chicago, I worked under Cole; "KC," we called him. He's the one [who] was my [first] supervisor. When I came to Oak Ridge, Cole had sent his [counterpart] to Oak Ridge. That was Howard Curtis. So, my immediate supervisor at Oak Ridge was Howard Curtis. We were all in the Health Division, but what my group was called, I really don't know. All I know is that we started working on building a "hot lab" and learning how to isolate the fission products and separate them, and we became so successful at that (and that's in one of those documents I left for you or I'm giving to you) that [the chemists] said, "Here's this guy Cohn and his group doing all this chemistry. They belong in the Chemistry Division." So I became Group Six in the Chemistry Division. I don't know if they ever had formal titles. Group One was Seaborg's10 group, with Pearlman. Other groups were headed by George Boyd, Milton Burton, [and Charles Coryell].

I spent most of my time at Oak Ridge during the war years in the Chemistry Division, but doing exactly what I told you I was doing: trying to isolate the individual fission products so they could be experimented with. The idea of using them in bulk [(therapy)] was not [even] in our thinking. No one had isolated these before. We became very successful at it.
YUFFEE: Which elements were you isolating?
COHN: As many as we [could] get our hands on. As many as had half-lives long enough to be worked on. Some of them have half-lives of seconds and are gone before you can even get the material out of the reactor.
YUFFEE: So, both short-lived and long-lived?
COHN: It was the long-lived ones that we were concerned with: They are the main biological hazards. The short-lived ones are gone before anybody could come into contact with them. To name just a few, there was barium, lanthanum, samarium, praseodymium, and neodymium, and all the [other] rare-earth elements. The ones that are in larger yield and of longer half-life,11 like barium, strontium, and cesium.
YUFFEE: You would isolate them and send them up to Chicago?
COHN: We first had to try to isolate them. We did [ship] some off to Chicago, and they were used experimentally up there and [the results were] published from up there. I had no knowledge of that until later on. I was profoundly uninterested. I was only concerned with the actual preparation of the material.
YUFFEE: Were they used for tracer studies that you know of?
COHN: Yes. I believe there are several publications in the Manhattan [Engineer] District12 [papers] from Chicago, and Finkle's name would be on some of them. The other names I've lost track of, because eventually I lost contact with the group I left in Chicago. It was exciting and interesting enough just to try and prepare these materials. This led into the idea of using the nuclear reactor to prepare other radioactive elements, nonfission products like phosphorus-32, carbon-14, etc., and that's the burden of that long document on isotopes from the Manhattan Project, the 10-page document.
FISHER: This Science article from 1946?13
COHN: Yes. So, the isolation of fission products [and] the preparation of nonfission products of potential [research] usefulness led to that catalogue.
FISHER: Do you recall what you thought, or what you think, as to basic objectives of this MED research? Do you think [MED's Division of Biology and Medicine was established] to treat overexposure to radiation?
COHN: Again, I go back to the fact that the use of radioactive materials [to study the effect of] radiation on human beings, or even on animals, was the farthest thing from my thinking. I had no interest in that; no part of it. I was interested in the preparation [of] radioactive isotopes for biomedical and chemical [research].
FISHER: I understand.
YUFFEE: Maybe I can take you back a little bit, since some of the people that you've mentioned have passed away and we can't get a chance to talk with them. We like to ask some of the people we talk to if they were close with people like Joseph Hamilton14 or John Lawrence,15 to see if they can tell us a little bit about them. For example, did you work with Dr. Hamilton when you were at Berkeley?
COHN: No. I didn't work with any of them. We worked separately. Each of us was an independent researcher. I was working on my Ph.D. in the Biochemistry Department. He was, I think, attached the Physics Department; and what experimentation he was doing, I don't know. We had absolutely no [work] contact other than personal contact with each other; no scientific contact. We were all part of the various people of various disciplines that were hovering around Lawrence's cyclotron [to obtain] the radioactive elements that could be produced there.
Use of Cyclotron-Produced Radiophosphorus for Ph.D. Research and Cancer Therapy

YUFFEE: Did you ever use any of the elements produced from the cyclotron in your research?
COHN: Yes, my whole [Ph.D.] thesis work was done with radioactive phosphorus produced in the cyclotron. In those days, I had to wait six months for the cyclotron to prepare a sample for me. Here's a guy whose whole graduate research was waiting on the vagaries of the cyclotron, which was a pretty new and experimental thing in those days. None of this was a routine business then.
YUFFEE: Were you doing tracer studies as part of your research for you Ph.D.?
COHN: That was my entire research, in rats.
YUFFEE: In animals?
COHN: In rats. I was using radioactive phosphorus because phosphorus is [an] important element, biochemically. Such things as tritium [(radioactive hydrogen)] and carbon-14 hadn't even been discovered or invented in those days. Otherwise, I might have gotten to use them, too. Getting back to radioactive phosphorus, my first wife, whom I married in 1938, came down with a type of cancer that required an operation and then a follow-up with radiation. The radiation was administered by radioactive phosphorus. That was a "human experiment," if you like, since it was very iffy whether the radioactive phosphorus would cure the cancer or not.
YUFFEE: Was it your suggestion to use the radioactive phosphorus?
COHN: No, it was the Department of Medicine. Robert Stone, I mentioned, was the head of the Department of Medicine. Radioactive phosphorus [was in general use] for treating leukemia and other bone diseases; [it] was a burgeoning experimental approach at that time.
YUFFEE: Just out of curiosity—
COHN: —[Not at all!] As a matter of a fact, many people were being treated with radioactive phosphorus from the cyclotron.
YUFFEE: Was is by injection or total-body irradiation, and how was it administered?
COHN: No, [the] radioactive phosphorus was either injected or swallowed. Radioactive phosphorus is a beta emitter16 and you can't use it from the outside [of the body] because [the radiation] won't get [into the blood and bone]. It will only penetrate a few millimeters, if that far, so you can't treat bones [from the outside].
YUFFEE: Is that where it localizes—in bones?
COHN: Well, bone is mostly calcium phosphate. And, of course, phosphorus is involved in other metabolic [processes], also. It tends to be deposited in bone, and that's where most of these tumors were located. That had already become a fairly standard treatment (using radioactive phosphorus) and I'm sure that's all in the medical literature from John Lawrence and other people associated with it. That kind of treatment migrated with the cyclotron. For example, MIT17 built a cyclotron and St. Louis18 built one. [They made] radioactive phosphorus for medical men to use in the treatment of cancers. It may have started in Berkeley, but it spread pretty rapidly.
YUFFEE: Do you know anything about how the isotopes that were produced in the cyclotron were [distributed] to other facilities that wanted to use them? Was there a formal process of other institutions trying to procure those isotopes?
COHN: I really don't know. All I know is that radioactive phosphorus from Lawrence's cyclotron from Berkeley was being used to treat people up and down the West Coast for cancer.

One of [those treated] was an attaché at the Soviet Consulate in San Francisco. It got one of my friends into hot water, because during a transfer of radioactive phosphorus for treatment of that person, somebody got the idea that my friend (who had prepared the phosphorus for this transfer) was a Soviet spy. They hounded him out of Berkeley and hounded him for [many] years thereafter. That's the famous Martin Kamen. You may have heard of him.
YUFFEE: That's unfortunate.
Push to Find Commercial Uses for Crocker Lab's Radioisotopes (1940s)

FISHER: You bring up a very interesting point when you talk about the very quick period during which all of this previously academic research was put to very practical uses in the treatment of cancer. I'm wondering how that manifested itself, from the fall of 1942 to spring of 1943, when the Manhattan Project, in a period of only six months, took all of this academic research-oriented [work] and put it into practical use with the creation of new elements on a larger scale.
COHN: Well, it's hard to answer your question, but I'll say this: the idea of using radioactive materials as tracers started in Denmark, well before [World War II]. Not the phosphorus produced by the cyclotron, but [by] radium-beryllium exposure. The basic concept was already in the field.

Now, [Ernest] Lawrence, with his cyclotron, was very anxious to get money to support not only the building of the cyclotron and its maintenance, but also to continue the running of the laboratory. Any possible use of radioactive materials, [any] practical use, he could use as a gimmick to convince donors to contribute money to his project.

When the idea of using radioactive phosphorus to treat leukemia19 and other cancer diseases came about, Lawrence was all in favor of it because it was a practical application [of what] had been, up to that time, pure research. He would push it.

The radiologists at that time knew about the dangers of radiation, but the use of radiation to treat cancer was already [well-known]. It goes without saying that if you could kill the cancer cells with radiation, you could also kill normal cells, and the hope is that you would kill the cancer cells off before you did much damage to normal cells. I think the people who use radioactive material in humans were [all well] aware of the fact there is a plus and a minus; there still is. Any radiation treatment, even today, runs a risk of damaging normal tissues.
FISHER: How about the transformation, during the Manhattan Project, from the theoretical idea that they could create large quantities of nuclear materials to the actual manifestation of that idea; that it could actually be done? Did that affect your work at Oak Ridge?
COHN: I would say, no. If anything, it was a foundation of my interest in doing what I did. I knew how important radioactive materials were, as tracers. I was profoundly uninterested in their use in treatment of any disease. Such things as radioactive cobalt for the cobalt "bomb"20 was not of any interest to me. Medical people would be interested in that, but I certainly wasn't pushing it.
Calculating the Toxic Effects of Inhaled Radioisotopes (Mid-1940s)

YUFFEE: There was a specific question I wanted to ask you that I should have asked a little time further back: I noted, in looking through some of your publications, that you did some research on inhalation studies in the mid-1940s.
COHN: You're talking about a publication about the toxicity of inhaled and ingested [radioactive substances]. That was just on paper and pencil. I didn't do any work at all; it was just calculation.
YUFFEE: Based upon what type of prior research?
COHN: Just the properties of the radiation itself; the energy of alpha,21 beta, and gamma rays22 and their metabolic routes, once inhaled or ingested. For example, the fact that strontium and phosphorus go to bones.
YUFFEE: Do you think this work became the basis of any inhalation studies done further down the line?
COHN: I doubt if anybody paid any attention to it. It was pure theory.
YUFFEE: Well, that's too bad.
COHN: Ingested, of course, is another matter. That means you actually swallowed it. Inhalation could be accidental. I didn't do any work at all; it was just paper and pencil.
YUFFEE: Was a lot of your early work—
COHN: —As a matter of fact, Karl Morgan23 did the same kind of calculations and published it six months later, using different symbols for the same things I was doing. I think he was a bit jealous that I invaded his field of Health Physics.
YUFFEE: Actually, I just spoke with Dr. Morgan a couple of weeks ago, and he mentioned that.
COHN: Actually, we had adjoining offices in the early days at the Oak Ridge National Lab, or Clinton Lab as it was called in those days.
Oak Ridge Graphite Reactor Becomes a Postwar Source of Radioisotopes

YUFFEE: Why don't you talk a little about once the war came to an end, and how your work changed or progressed at Oak Ridge.
COHN: Well, I had become aware of the fact that the reactor does more than convert uranium-235 and create plutonium-239. I was aware of that. I was also aware of the fact that it is a neutron24 generator, and the neutrons could be used to make other radioactive substances. For example, even Lawrence's cyclotron, which used deuterons25 to produce 32P [(phosphorus-32)] from 31P, was essentially adding a neutron to 31P. But, here [in the reactor,] you had a neutron generator; you don't have to have a cyclotron. Therefore, exposing things to neutrons in the reactor would produce radioactive substances by transmutation. For example, to make 32P, you expose sulfur and you extract the radioactive phosphorus from the sulfur.

So, I was aware how important they were to my field of biochemistry and [to] biology, in general. Also, I was spurred by people on the outside who were aware of this fact, once the veil of secrecy was lifted in 1945,26 and urged this course of action on the Project. I was the guy who was already making radioactive materials.

We sat down and figured out what we could make by exposing things in the neutron generator—that is, the reactor. That was the source of the [isotope] catalog that was the Science article; essentially sitting down and saying, "We can make this from this in such activity," all of which was in the literature, by the way.

Obviously, the administration of the Project was all in favor of this because here was a [long-term] use for the [Oak Ridge] Graphite Reactor. It was no longer of any use [for plutonium production], because Hanford was operating to make plutonium; and the Graphite Reactor made only thimblesful, against the [large amounts] we made at Hanford, Washington. So, I had plenty of encouragement from the administration to embark on the construction of that catalogue.
Work With Aebersold to Create the Isotopes Distribution Committee (1946)

YUFFEE: And this was for the purpose of distributing—
COHN: —making isotopes available to qualified researchers, yes. If you read the first part [of the 1946 Science article], the administration part, that's what Paul Aebersold27 was responsible for. I wrote the second part—what could be made, what activity, and how much, and so forth.
YUFFEE: Did you help play any role on the administrative side?
COHN: No, except we were in close contact. I was aware of what he[, Aebersold,] wrote, and [I was] in a position to make criticisms, and he was in a position to ask me questions about the technical side, which I was in charge of.
YUFFEE: Did this lead to the formation of the Isotopes Distribution Committee?
COHN: I think it was a combined putsch28 of Aebersold and myself which led to the formation of the committee. We weren't in [a] position to do anything; after all, we [were] still under hierarchical command, going right up to General Groves.29
YUFFEE: Was it General Groves who first pushed the notion making use of the [Oak Ridge] Graphite Reactor and distributing isotopes? Who was it who thought we should, or the AEC30 should, distribute?
COHN: Aebersold and I did. We went up through the chain of command and they were all in favor of it, so the order came back and said "Go ahead and do it." So, I can't claim that I had the authority to do it, but I can claim I was part of the inspiration to get it done and get the authority to go ahead and do it.
YUFFEE: This may sound sort of mundane, but one of the areas where we been having trouble finding information is on the administrative workings of the committee: How did the process work when a qualified researcher wanted to procure some of the isotopes?
COHN: You mean after the system was set up?
COHN: Well, that's all set out in the first part of the Science article: who applies to whom and what committees have to pass on it.
YUFFEE: Did it actually follow what was set out in the guidelines?
COHN: I believe it did, but it was all in Aebersold's department. He was in charge of the [distribution]. I was in charge of the production of the material itself, the preparation, and the shipping; everything from insertion of material in the reactor to extracting it, packaging it, and preparing it for shipment.
YUFFEE: Were the same standards used?
COHN: I got my orders about what to ship to whom from him [in] the Isotopes Division of the AEC—that is, from Aebersold.
YUFFEE: Did you sit on the Isotopes Distribution Committee?
COHN: I probably sat on it and may have fallen asleep during the deliberations. It was all set up for P.R.31 purposes, but I do think it was followed very carefully because we [were] still under military dictatorship, so to speak.
General Groves's Relations With the Scientists

FISHER: Was it very much of a "military dictatorship?"
COHN: Well, General Groves had to pass on everything.
FISHER: And he ruled with an iron fist?
COHN: Well, he was the boss. For example, when it came to pricing these things, Aebersold and I recommended a certain price structure. For example, for carbon-14, General Groves wanted a price on it that, essentially, amortized the construction of the reactor itself, which was a [war] project. I got him to the phone and I said, "Look, General, you put that price on carbon-14 and you won't sell a microcurie of it. It has to be priced where people can afford it and you have to write off the Graphite Reactor as part of the war project. You can't [put] it on the back of biological researchers." So we got decent prices.
FISHER: So he rolled over in that instance?
COHN: Oh yeah, he rolled over on a lot of things, like keeping Oppenheimer32 in charge although he was convinced he was a neo-Communist. You know all about [that]. That's public information.
FISHER: Tell us something we don't know—
COHN: —Groves had to yield on a lot of things.
FISHER: Can you give another example we haven't heard?
COHN: Every month we [had] to have Project meetings at the University of Chicago, during the war years and for a short time thereafter, where the leaders of the various projects (like Oak Ridge and Ames33 and at other places). We met for a couple of days to exchange information. This was highly secret, of course

.At one of these meetings, I remember General Groves being present, and he wanted to address the assembled multitude of high-powered scientists (including me), and he said, "If you guys don't make this work, my ass is in a sling." In other words, he admitted that he was entirely dependent upon the scientists and engineers to make it work; he couldn't do it himself.
FISHER: So, he really did listen to them, as in the pricing of the radioisotopes?
COHN: There was an element of reasonableness in his dictatorship.
FISHER: You'd be surprised. It's remarkably difficult today to try and weed out all the information that's there to come up with an accurate representation of the power structure and whether it was a case of the tail wagging the dog and who really was in charge, etc.
COHN: Well, it went both ways. Colonel Nichols34 was here in Oak Ridge and he was Groves's second-in-command. Something that might have originated with me would go out through the Laboratory power structure from the Director of the Laboratory to Colonel Nichols, and if he couldn't decide, he'd bump it up to Groves. He would decide, and his decision would come down the same chain [it had gone up]. A lot of discussions could be made right at the Laboratory, but when it came to producing materials at Government expense and selling them outside of the Laboratory, this would be a major a policy decision [that] could not be made entirely within the Laboratory.
YUFFEE: Did the system change at all when the AEC took over?
COHN: I think it must have changed, but remember that by 1947, I was out of the business altogether. I had moved to [the new] Biology Division and was doing nucleic acid35 research.
Transfer to the Oak Ridge Biology Division (1947)

YUFFEE: That was the end of your—
COHN: —end of my involvement with radioactive isotopes, 1947.
YUFFEE: What made you decide to make that switch?
COHN: It was obvious that isotopes were going to be a major production facility operated out the Laboratory, and therefore it [would be] on a long-term basis; not this hand-to-mouth business under which we were operating until then. I was asked if I wanted to be in charge of the [Oak Ridge] Radioisotope Production Division far into the future and I said, "No, I'm a biochemist and I want to go back to biochemical research." I transferred to the Biology Division, which had been set up in 1947.
YUFFEE: Was that under Alex Hollaender?
COHN: Yeah. He said, "Why don't you come over and join us?" So, I gave up isotope production altogether.
YUFFEE: What type of work did you then do—nucleic acid studies?
FISHER: The ion-exchange36 chromatography37
COHN: I brought that from my fission-product separation [work], because our big contribution to the chemistry of fission products was introducing ion-exchange chromatography as a way of making [isotope] separations. We made the first clean separations of radioactive rare earth [elements] produced [by] fission, which was quite a chemical advance. We published that in the Journal of the American Chemical Society, along with 11 other papers on the same subject. You're probably aware of that.
FISHER: Can you talk a little more about the nature of that work and the role it played in your research later on?
COHN: Well, having developed ion-exchange chromatography and learned how to use it to separate materials that are difficult to separate any other way, that can't be separated by precipitation38 or volatilization39 or solvent extraction40—ion-exchange chromatography is extremely useful. It was quite a technical advance in chemistry.

When I went back to the Biology Division, I got involved with nucleic acid research, which I'd just had a trace of interest in when I was an graduate student. One of the problems of nucleic acid research was separating the various hydrolysis41 products of nucleic acids: So, I applied ion-exchange chromatography, and that not only separated them cleanly, but even discovered dozens of new nucleotides42 whose existence hadn't been discovered.

I became very prominent in the field of nucleic acid chemistry and published in that area for many years. In fact, I stayed in that field until I retired in 1975. In a way, I am still involved since I'm editing, for Academic Press, a series of volumes in this field. I didn't do any radioactive work or have anything to do with radioactive isotopes after 1947.
Adherence to Radiation Standards

FISHER: Just one quick question: Before you left the area of radioisotopes, during the time that you were involved in creating these materials down here in Oak Ridge, were you ever concerned or ever involved in any way in a program of standards that might have been established? Did that enter into your work, or your concerns, at all?
COHN: It did. We were aware of them. We were always aware of the hazards. After all, the radium-dial painter studies were back in the '20s, and my boss at Harvard was the person who discovered that, so I was aware of the effects of radiation on living matter. I was aware of it, and the whole project was aware of it, since my part of the project was under the supervision of Robert Stone, who was a Professor of Radiology, and my next-door neighbor in the Laboratory was Karl Morgan of the Health Physics Group. We were very much aware of radiation hazards and what the standards were. We had all kinds of instruments and devices that were always telling us what we were being exposed to, and those things were being monitored every day; film badges,43 for example.
YUFFEE: Was it Karl Morgan's group [(Health Physics)] that was doing the monitoring?
COHN: Yes, that was their part of the project.
YUFFEE: Sort of just the occupational health physics aspects of it?
COHN: Instead of…?
YUFFEE: I guess, as opposed to a more research-oriented health physics aspect?
COHN: It was research, but also protection of personnel. I remember once, for example, transferring some "hot" liquid from behind the lead barrier to a container on the outside, a very small amount of liquid in a glass tube. We had to take it out of the barrier and drop it into a container. Very short exposures were involved, but one drop fell on the floor. Well, we could have stopped right there and cleaned it up, but instead we decided to put a [lead] brick on top [of] it, which essentially kept us protected from radiation. When Karl heard about that he said, "Yes, but someone could stumble over the lead brick, so clean it up!"

One kind of [problem] introduced another. I'm just giving you an example of the interplay between health physics and my isotope work.
FISHER: Do you recall any discussion of maximum permissible doses that were permitted for your colleagues in your labs?
COHN: We were [all] aware of that. There were standards; the International Commission on Radi[ological] Protection, I think it's ICRP, or something like that, those standards were well known and we all read them. Karl Morgan was certainly aware of them. Most of those had to do with external radiation exposure, to an x-ray tube or to a gamma source [for example]. They hadn't begun to consider internal radiation. That's where Karl Morgan and myself, with our calculations, were coming into place.
FISHER: In fact, some of your calculations led to a whole new standard for determining dose, which was then applied to occupational situations.
COHN: Yes, they could. We were aware of the dangers. We took every reasonable precaution to stay out of those and didn't do things that would expose anyone to radiation.

Have you ever been to Oak Ridge? You haven't seen the Graphite Reactor, for example?

There's a picture there of one step in our operation, during the preparation of fission products. We got these irradiated uranium slugs about six inches long out of the reactor, [and] transported them behind heavy lead shielding to the top of our "hot" cubicle, where we were going to [dissolve] it and isolate the fission products. To get it from the lead container into our "hot" cell involved taking it out momentarily and transferring, which means that the person who was doing the transferring would be exposed to the radiation from the "hot" uranium.

We [constructed] a fishing pole, about 8 feet long with a grabber at one end and a handle at the other. Paul Shallert practiced [the transfer,] and doing it in less than eight seconds. We figured that eight seconds would give him the maximum permissible dose for that day. His instructions were that if he couldn't make it in eight seconds, [to] drop it and run: somebody else would come and try to do it.

We were wary of these things. We tried to make the calculations to stay out the danger range, or within the permissible range, as it was known at that time.
FISHER: But, point in fact, you probably wouldn't have let those recommendations stand in the way of your work personally?
COHN: We would have figured out some way to get around it, by having someone else try it and see if he could do it [in] eight seconds.
FISHER: I think that those stories and anecdotes are fun. That's an example of stuff that we cannot get from reading Newell Stannard's44 books; he doesn't talk about that kind of stuff.
COHN: You're getting down to the personal interaction level.
FISHER: Which is the benefit, the real benefit, to readers of this transcript later on.
COHN: There are various pictures on the second floor of the Graphite Reactor building showing my group in operation making radioisotopes. Every one of them is wearing a film badge. The person doing the transfer—there's a picture of him mimicking the transfer—he's wearing a [dosimeter] ring on his hand. That would be the closest thing to the source, even though it was at the end of an eight-foot pole.

There were monitors hanging around in all buildings in case anything got loose that we didn't know about; they would sound an alarm so everybody would run out of the building until they found out where the trouble was and there could be some kind of cleanup.
YUFFEE: In our interview with Dr. Morgan, he mentioned uranium slugs and he said that he noticed, when he first got to Oak Ridge, that the workers were carrying them without their lead gloves because they found the lead gloves too cumbersome to work with. He found that to be a concern.
COHN: Those were slugs before they went into the reactor. After they came out of the reactor, nobody handled those things, except with tongs, and [from] eight feet off, and one at a time. He was talking about the material going into the reactor. Those uranium slugs were canned in aluminum jackets. The only radiation coming out of [uranium] radiation is alpha radiation,45 which won't penetrate the dead skin on your hand, let alone the aluminum jackets. So, it's perfectly safe for a worker to pick up an aluminum-jacketed slug and put it on a tray and push into the reactor.

There's no radiation to get to and there's no radiation on the aluminum slug. The radiation is all in the uranium on the inside. Further, most of the radiation from the uranium doesn't even get out of the uranium itself. It has to penetrate uranium to get to the outside. Some of the radiation that originates from the outer edge of uranium could get out of the uranium, but then it would have to pass through the aluminum jacket, [which it can't do].
Self-Experimentation With Radioactive Tracers

FISHER: I have another question to ask you: Did you ever, during the course of your tracer studies, use yourself as a subject?
COHN: Out in Berkeley, I did. For example, we learned how to make radioactive sodium, and we were interested in how fast blood flows from this arm (holding out one arm) [to] get to this arm (holding out the other arm). We would inject ourselves with a little bit (a tracer amount) of radioactive sodium and then hold onto a Geiger counter and count 1, 2, 3, 4, 5, tick, tick—it's over there [in the second arm]; so you see how fast the blood is migrating. That's an example of [a] self-inflicted radiation tracer experiment.

I emphasize the word "tracer" because these amounts are infinitesimally small. We were quite willing, though, to take whatever chances there were.
YUFFEE: So, would you say this was fairly common practice among researchers, especially at Berkeley, to use yourselves in tracer studies?
COHN: Well, it was [a] practice among researchers everywhere, actually. The tracer doses are almost definable as ones that will not induce any untoward physiological effects.
FISHER: Well, there's certainly—
COHN: —For example, the difference between radioactive iodine to diagnose a thyroid46 problem [and] radioactive iodine to treat a thyroid problem. The dose range is over a million; you might use a fraction of a microcurie47 for a tracer experiment, but you use maybe a millicurie48 or more for actual treatment of thyroid [cancer]. [Also,] there are repair mechanisms for radiation damage, and a very small amount of radiation might do a little bit of damage, but it's repairable, whereas if you override the threshold, you could get into trouble.
FISHER: Do you think that's what happened to Joseph Hamilton? There are some very widely known stories about that he would use himself as a subject in his classes, practices which may have led to his early death.
COHN: That's all supposition, about them leading to an early death. I wouldn't be surprised if he did, for example, swallow some radioactive sodium or [radioactive] sodium chloride, table salt, for a class and have his hand on a Geiger counter here and let the students see how long it took for the ingested dose of sodium chloride to actually get into the bloodstream and be circulating. I mean, I can imagine him doing that kind of experiment, and I would have done it myself if I had been in a position to need that kind of experiment.
FISHER: Well, those are exactly the sorts of experiments that I have read about Dr. Hamilton [doing]. I'm not sure what substances he ingested, but I've read about him doing these repeatedly in public demonstrations.
COHN: It probably involved radioactive sodium, because sodium has about a 15-hour half-life. So, in about a few days, it's all gone. And, it's a gamma emitter: it doesn't localize any particular place.

As a matter of fact, my ex-wife died, in 1941 I believe it was, and I remember once when she ingested some radioactive sodium as part of one of Hamilton's experiments. [Just] after that she came [down] from the Radiation Lab, where this had taken place, down to my lab, where I was trying to measure radioactive phosphorus on my Lawritzen electroscope.49 The minute she walked into the room, the background of my Lawritzen electroscope went up. From 15 feet away, that's where the gamma radiation was affecting my electroscope. A very tiny amount of it was enough to influence my counting mechanism.
FISHER: Well, was your wife a part of a cohort that Dr. Hamilton was studying, or was she just a volunteer, as a friend?
COHN: She was like myself: she was working for a Ph.D. in the same department at the same time I was. At that time, we weren't married.
Researcher Knowledge of Radiological Hazard and Informed Consent

YUFFEE: One question that you may have thoughts on, or you may not, is that with tracer studies, the biological hazards from them are close to nil. In your mind, is there a philosophical difference to be made about a tracer study done on a willing or knowing patient versus somebody who doesn't know that they're having a tracer administered to them?
COHN: I really can't answer that question. At the time that Hahn at Nashville50 was doing his experiments, he certainly believed that the amounts of radioactive iron he was using (fractions of a microcurie) were innocuous. Whether he discussed this with the subject[s] or not, I have no way of knowing. But certainly, he was well aware of all the hazards of radiation; he's among the people [who] wrote the standards.
YUFFEE: Who's this?
COHN: Paul Hahn, at Vanderbilt [University in Nashville]. He's long since dead, but he [(meaning his work)] and Vanderbilt are part of class-action law suit involving radioactive iron immediately after the war years. It's a roundabout way of answering your question. The people doing these experiments were well-aware of whatever was known at that time about hazards. Whether they would discuss them with the subject[s]—I use the word subject, rather than patient—I can't answer.
FISHER: Since we're talking about stuff going on at Berkeley, I once read an old Met Lab monthly report that talks about a visit you made to Dr. Hamilton at Berkeley to assist in a model experiment on gaseous fission products. I was wondering if you could talk about the internal-emitter toxicology51 program in general at Berkeley.
COHN: I have no knowledge of it at all. If I did have the knowledge, it's long since vanished from my memory, because I can't remember such a visit or such a consultation. I did make two or three trips to Berkeley from Chicago right after I joined the project to find out what was going on there that might influence my work on radiotoxicology, but I don't remember any work of that kind there or my involvement in it.
FISHER: Fair enough.

Research on Nucleic Acids

YUFFEE: Maybe you could tell us a little bit more about the nucleic acid studies that you did.
COHN: Well, they have no relevance at all to radiation.
YUFFEE: Yes, but it'll give a well-rounded view of your work.
COHN: Well, when I came into it in 1947 I wanted to investigate the turnover, the half-life, of nucleic acids. In order to do that I needed to separate the four nucleotides (the adenylic, guanylic, cytidylic, and uridylic acids), of which RNA52 is composed. The idea was that I would inject an animal with 32P, isolate the nucleic acids, and then isolate the four nucleotides and see how radioactive each one of them [had become]. It's rather an elementary, stupid experiment, but it was one way of getting started.

I never got around to doing those experiments, because I got more interested in the chemistry of separating the four nucleotides, which never [had] been done before in any reasonable way. So, I applied ion-exchange chromatography and [thereby] found out that they could all be separated very simply.

But in the meantime I found out there were other nucleotides there that we hadn't been aware of. So, one thing led to another, and I found myself knee-deep in investigating the basic chemistry of RNA rather than the turnover that I had in my mind. That technique of using ion-exchange chromatography to separate the nucleotides permeated the whole field of biochemistry and was applied to many other things: separation of sugars and sugar-phosphates, and other biochemicals. Column chromatography, as it's now known—
YUFFEE: —Chromo chromatography—
COHN: Column chromatography, the idea of flowing things down a column in such a way that they emerge at different [times at] the bottom; you get the first one, and then another, and then another.
YUFFEE: Is this through a gel or what type of—
COHN: —The material in the column is a sort of gel, yes. Actually, the whole term chromatography, chrome from color, goes clear back to work done in Poland even before the turn of the century. I forget his name right now; [the researcher] was flowing a mixture of plant pigments down a column of starch and finding out that by washing that stuff through the column the different pigments appeared at different times at the bottom. So, just [add] the word chromo- for color, to -graphy, meaning "separation of." So anything where you flow things down [a] column as a mode of separation is known as chromatography, even though [visible] color may no longer [be] a part of it.
YUFFEE: Do you think that the early work you did in trying to separate the nucleic acids—I'm familiar with research done at Brookhaven53 and maybe other places, where they were eventually able to tag specific nucleotides or nucleic acids and then use that.
COHN: It's become very common. For example, in the O.J. Simpson case,54what do you think all of those [nucleotide] bands [in the DNA-comparison charts shown by the prosecution]—
COHN: —They are all labeled with radioactive tracers. The bands are radioactive. That's part of the DNA "fingerprint" technique. You fractionate56 the thing and put a label on each [fraction], and then you separate them, and then you can detect each one is by its label because the amount of material is infinitely small.

So, I think that the work on column chromatography led, through one change or another, into that sort of work and into all the chromatography work in all kinds of fields in biochemistry, as a general separation technique. When I visited Osaka, Japan, back in the 1960s, my work was already well-known and was being used: that is, the chromatography of nucleotides. They took me to an observation room in the administration building and showed a view of what look like a tank farm: huge cylinders connected with pipes. They asked me, "What do you think those are?" And I said, "It looks like an oil refinery to me." They laughed and said, "Those are your ion-exchange columns." They were preparing nucleotides [on a massive scale] by the column techniques I pioneered some 10 years earlier.
YUFFEE: That must be gratifying to see it in a—
COHN: —so it could be used in a preparative way. Some of those nucleotides are used as flavors and other things like that. It's a big business in commercial chemicals.
YUFFEE: Did you patent any of this work? Is that something you could have done?
COHN: The column chromatography was never patented. It was all published and everybody used it. I did patent the method of making 32P from sulfur in the reactor, at the urging of the attorneys. Otherwise, I wouldn't ever have thought about it. I do have one patent; not hundreds like my colleagues [may] have.
YUFFEE: But it's interesting to note how much was being done, and how many advances were being made and funded by the Government, and how a lot of them went unpatented so that they could be used generally by everyone.
COHN: It became part of the whole scientific enterprise. There was some resistance to allowing us to publish at the very beginning. I remember my first paper on nucleic acids was held up by the [security] classification office; they saw the word nucleic and figured it had to with atomic nuclei rather than cell nuclei. After explaining to them, I was allowed to publish.

The patent on 32P was held up for years because Groves's advisors said that from it, a knowledgeable person could calculate the power of the reactor—which was all nonsense, because it was only a little experimental reactor, the Graphite Reactor here. This indicates that the wartime secrecy thing had a quite a bit of aftershock.

Getting back to nucleic acids. My application of ion-exchange chromatography to the problem I told you about, leading to the isolation of different nucleotides that had not been discovered, led rather directly to the discovery of what is now known as messenger RNA, which is the way information gets from the DNA to the protein that it specifies.

The messenger RNA had been a theoretical concept until my colleague Vullein, [whose office was] next-door to mine, applied both column chromatography and my radioactive phosphorus to the problem of how viral RNA influences the transformation of [the cell] into making more virus. So, by application of two things in which I was involved (radioactive phosphorus and column chromatography), he was able to actually show that viral RNA is the long–sought-after messenger RNA, or that messenger RNA is that substance which is produced directly from the DNA and carries a message into the cytoplasm.
YUFFEE: Takes me back to biology in high school.
COHN: I hope what I said is clear because—
YUFFEE: —Oh, definitely.
FISHER: As long as you bring it up, I do have one question I might ask you: Could you please spell the acids that make up RNA for us because it will be very tough for me to look that up when we edit this transcript.
COHN: Yeah, you want it?
COHN: A-D-E-N-Y-L-I-C, G-U-A-N-Y-L-I-C, C-Y-T-I-D-Y-L-I-C, U-R-I-D-Y-L-I-C.
FISHER: You saved us hours of research on those alone, I can assure you.
COHN: To be technically correct, each is followed by a space and then "acid."
YUFFEE: And these are components of the nucleotides—?
COHN: They are the components of [ribonucleic acid] (RNA).
YUFFEE: Such as—
COHN: —which is composed of those four nucleotides in various arrays. The order in which they appear in a nucleic acid in triplets are what specifies amino acids going into protein. Each triplet of three nucleotides specifies one amino acid. For example, A-A-A in a row will specify one particular amino acid. Since there are 20 amino acids in about 60 combinations of triplets, you can see why I don't have them all in my head.
YUFFEE: (smiling) We'll forgive you.
FISHER: (smiling) That certainly is complicated and over my head.
COHN: The whole idea of the information-transfer DNA is like RNA; it's composed of the same four nucleotides except that the uridylic is now a thymadylic, but that's a minor point. If you arrange those in triplets— one, two, three, four, five, six, seven, eight, and nine—[then] one, two, three, will be one triplet; four, five, six, another; seven, eight, nine will be another, and so on. Each one of those triplets will specify one amino acid in your final protein. Each one of those triplets is transferred to RNA, (that's the messenger RNA), which will carry that message from the DNA to the cytoplasm57 so the protein can be made.

That's your information transfer chain, and the nucleotide sequence is the basis of all of it. All of those bands you see on the TV from O.J. Simpson's DNA test are strings of nucleotides: they may be 7, 8, or 9, or 10, or 12, or 14 [nucleotides] long, but each one will be a different sequence, and that's why they migrate to different levels. Then they're detected by the radioactive tracer on them, and the distance that they move tells you how many nucleotides there are in each one.
YUFFEE: Did you say what you figure that the tracer was? You know what tracer they would probably use?
COHN: Probably phosphorus[-32], because it has a long enough half-life, maybe two weeks, to stick around for a long time. [If] they used something that is short-lived, like sodium (15 hours), in two days, you would be out of stuff: it would be dead.
FISHER: So, the next question is, do you think [he] did it?
COHN: My intuition says yes, but I admit that proving beyond a reasonable doubt will be pretty hard since there were no witnesses.
Use of Radioactive Isotopes Assessed in Context

FISHER: Michael is the lawyer and we'll leave that to his colleagues. I do have another question for you about the establishment of radioisotope policy: Are you satisfied with the way this turned out in later years, after you left the area responsible for the manufacture of radioisotopes and [after] you constructed this [distribution] policy with Aebersold? Are you satisfied that this policy met the expectations of those people involved and that it was [a] productive and positive way for the effective distribution of these radioisotopes?
COHN: I think that the whole [business] was an enormous boon to human welfare. Oh yes, I'm extremely positive about the whole thing. All this ruckus that has been raised now, that these tracer doses are somehow "radiation experiments on humans," I think is quite false; in fact, [it is] beside the point.

I'm still mad at [Secretary of Energy] Hazel O'Leary for releasing all those documents without explaining that some [involved] tracer amounts, which are not radiation experiments on humans. It should be completely separated from experiments on humans, like the blasts out in Nevada, or Utah, or wherever they were. Also, I think she should have distinguished [them from] cancer treatments, which had a long history. Those are radiation treatments of humans, but they're not experiments in any sense of the word.
YUFFEE: Would you include in that category the TBI [(total-body irradiation)] studies that were done at ORINS,58 that have gotten pretty wide publicity?
COHN: My impression of those is that they were all cancer treatments.
Studies of Pregnant Women With Radioactive Iron (1945–49)

FISHER: How about the studies at Vanderbilt?
COHN: What studies, the radioactive iron?
FISHER: Well, the pregnant women studies.59
COHN: That was radioactive iron as a tracer, using a tracer dose. I've been privileged to see one of the reprints of one of the papers that Hahn published, and he says that 100,000 counts per minute [were administered]. That's a minuscule dose; that isn't even a microcurie.
FISHER: And whose paper was that?
COHN: Paul Hahn. It's his experiments that were the so-called Vanderbilt Experiments.
FISHER: Do you think that because they occurred on pregnant women, they have become a "sexy" issue for the news media and really have no scientific validity or cause for concern?
COHN: I would throw the case out of court, but then, [the] judge isn't a scientist. I think the class-action suit is simply a way of using this as a [way] to get some damages out of the Government. I think it's a nuisance suit, too: I don't believe any damage was done. Now, whether or not informed consent was given, I don't know. At the time, there was no reason to give informed consent because it was commonly believed that [that] amount of radiation would not be toxic or dangerous. But whether or not an informed consent was asked for, or given, I have no way of knowing. My whole knowledge of this has just come about in the last two or three months, when I have been besieged by both parties to the suit for affidavits on [the production of] radioactive iron.
YUFFEE: Is this [the] first time you've been asked to be involved in a litigation?
COHN: Yes, and all because of that [1946] Science article [by Hahn] that says that we would supply radioactive iron under those conditions and so forth and so on. But again, reading the Paul Hahn article that they gave me a reprint of, it says he got his radioactive iron from a (d, p) reaction, which is "deuteron in and protein out." That's a cyclotron product; that's not a reactor product.
YUFFEE: Would that have been a cyclotron at Vanderbilt, or would that have been one near Oak Ridge?
COHN: There was not one at Oak Ridge that was supplying radioactive iron. We would [make] radioactive iron by [an] N-gamma reaction in the reactor, but Paul Hahn said it was produced by the (d, p) reaction. This indicates the iron came from a cyclotron, and Oak Ridge didn't have a going cyclotron, nor was it supplying any radioactive products other than the reactor products.
YUFFEE: There was someone whose name I came across: C.W. Shepherd—
COHN: —He worked with Hahn, and then he came and worked with the Biology Division—same division I moved into—in 1947.
YUFFEE: He was with Hahn through the studies. He would have also procured the radioactive iron from a cyclotron?
COHN: I don't know whether he was with Hahn on that study or not, because his name would have appeared as an author.60 I think he may have left. He was with him during the war years. I don't think he could have been [involved in the study] because—I think those experiments were done in 1946 or 1947, and Shepherd was in the Biology Division in 1947. So, I just don't know.
No Human Subjects Used by Oak Ridge Biology Division

YUFFEE: Do you know of any studies using human subjects done by the Biology Division or the Health Division?
COHN: None were ever done by [the] Biology Division, period.
YUFFEE: Karl Morgan said the same; he didn't think Alex Hollaender would have done that.
COHN: The ones done by the Oak Ridge Associated Universities, or ORINS, as it was known in those days, I am convinced, were all cancer studies and had nothing to do with experiments, as such.
YUFFEE: These would be the studies beginning with Dr. Gould [Andrews] and then Lushbaugh?61
COHN: Yeah, they're all medical people.
FISHER: How about Hamilton at Berkeley?
COHN: I have no way of knowing. I left there in 1938. I had limited contacted with them. We were not colleagues in the sense of ever working together. [Our relationship] was part of a loose array of biologically-minded people around the cyclotron.
FISHER: But, it was still a pretty closed community, especially during the war years, don't you think? Or am I wrong in that perception?
COHN: I left [Berkeley] before we got into the war. I left there in 1939. As a matter of fact, I was on my way to Harvard when Germany started World War II. I heard [about it] over the radio while I was en route.
FISHER: You didn't remain aware of the work that other individuals, even across the country, were doing?
COHN: No. Again, I didn't join the project until late 1942 and early 1943. There is quite a hiatus there.

I warned you over the phone that I had nothing to do [with] human radiation experiments.
FISHER: That's fine, but it doesn't negate the value we glean from sitting here with you this morning.
YUFFEE: In fact, the information on the creation of the Isotopes Distribution Committee and whole radioisotopes distribution is very useful, and that was one of the reasons—
COHN: —I regard that as an unmitigated good; in other words, it's triple A-plus, ranked number one.
Creating the Oak Ridge Symphony Orchestra (1944)

FISHER: And it's the thing you're most proud of in your work?
COHN: It's one of three things, certainly. Chromatography is one, because that's permeated the whole field of biomedicine and biology and biochemistry and whatnot. The work on nucleic acids which came out [of] that and led to the discovery of messenger RNA and a way of analyzing nucleic acids and—I'm going to throw you a real hooker.
FISHER: Fire away.
COHN: The creation of the Oak Ridge Symphony Orchestra.
YUFFEE: I was going to ask you about that, actually.
COHN: We just celebrated [its] 50th anniversary.
YUFFEE: One of the questions I wanted to ask you about that was, when you started it in 1944, under what was still the strict veil of secrecy—Oak Ridge being a secret town—was it because you were in a closed community where there were other musicians like yourself?
COHN: Well, if you have a few minutes I can give you the story.
YUFFEE: Yeah, please.
FISHER: (smiling) I'm secretly hoping asking for actually more than that, but maybe not on tape.
COHN: You can put on it tape if you like; it's also summarized on one those C.V.'s that I gave you.
FISHER: (smiling) I'm hoping for a short recital, maybe, later.
COHN: I moved from Chicago [(the Met Lab)] to Oak Ridge on September 30, 1943. I didn't bring my wife and the child I had gotten with my first wife (who had since died) with me because there was no place to live yet: they were still building the houses there. I did bring one thing with me, besides my extra shirt, and that is the cello you see out in the music room here. I transported that first. Left my wife behind.
YUFFEE: (smiling) Does that mean that the cello was your first love?
COHN: Since I was 11 years old. I was 33 years old when I moved to Oak Ridge, and I always played mostly quartet music, occasionally [orchestra] music if I had to. I have been immersed in the practical side of music all my life.

So anyway, after I got a place to live and started to work at the Laboratory, I started looking around for people to play with. First, I met a violinist, and then another violinist, and [soon there was] a group of us who were interested in [making] music. [We] met at the high school.

There were eight wind players and three string players, and I said, "This is no way to form an orchestra; you need lots of strings and very few winds. So, you guys with winds go form a band, and I'll take the two fiddlers and see if we can get enough for a string quartet," which was what I wanted. First thing, we found one, and then another.

I had some simple string-orchestra music. We started to meet at my house and play string-orchestra music, just for fun. And then, the word got around, and the first thing you know, there were more and more string players showing up: "I played in college," or "I played in high school and I like to play," [they would say]. Soon, there were more people than could be accommodated in my living room, which was in a house smaller than this.

Finally, we petitioned for a school room in one of the schools, got it, and then we [were] all spread out and we couldn't stay together [in tempo etc.] at all, and [the orchestra members] said, "You're the organizer, so you have to be the conductor." I stood up and I became a conductor. I had enough orchestra experience to know what conductors do, so the first thing I knew I had a 20-piece string orchestra.

Then, the various wind players heard about this and they said, "Look, we'd like to get in on this, too. Why can't we make it a full orchestra?" I said, "Okay, we 20 string players will first give a little concert to get that out of our system, and then we'll add the winds and make it a full orchestra." In June 1944, we had a string orchestra concert. Remember, this all occurred [from] September [1943] to June 1944. We added the winds in November 1944, and I had a full symphony. We gave a symphony concert—
YUFFEE: —Oh, that's great!
COHN: —playing legitimate music. I mean, we played Schubert and Mozart; pretty badly, I would say.

These were 100 percent amateurs. Some of them did shift work.62 We couldn't get [full] rehearsals because [some] worked at night and transportation was tough because there was gas rationing [and the] streets weren't paved; even the main street was still just gravel.
YUFFEE: Did you have difficulty filling in specific instruments; did you have trouble finding a bass player?
COHN: The funny part is, I had no trouble for the first concert. Actually had two bassoon players. The first bassoonist was named Auguste Schmidt. What a good name for a bassoon player! I have a picture of him and Oriel Snyder. The second concert, I had one bassoon; the third concert, I had no bassoons. I became expert at re-scoring. I re-scored bassoon parts into French horns, of which I had many, and into clarinets, of which I had many. Anyway, that's where it all started.

When the end of the war came, people started leaving, and I suddenly had half of an orchestra left. That's when we started [to] bring in professionals from Knoxville, to fill in holes, and it's been that way ever since. It's been basically a volunteer orchestra, with various holes in critical places filled by professionals, mostly from Knoxville. Right now, it's about 50/50, but most of the [old] amateurs are dying out. [There are] only four of us left from the full 50 years. There aren't so many new volunteers coming into Oak Ridge, because the crowd of people that's been coming in the last few decades has been mostly business people and engineers, and not college-trained musicians.
FISHER: Any names that we would recognized from the early years?
COHN: As far as players, you wouldn't recognize any. As far as soloists with us, you would recognize a few names. In the first season, we had someone name Menuhin; not Yehudi but his youngest sister, Yaltah, who was the baby of the family and the one the family decided shouldn't be a musician. They didn't push her like they pushed Yehudi. Her Army husband happened to be stationed in Knoxville, and I had known the Menuhin family since my California days, because I'm a native Californian, by the way—not just college—so I got her as a soloist.

We got Albert Spaulding as a soloist. I got Isaac Stern, in 1948, on the basis of an old friendship. There are probably some others that you may or may not have known.
FISHER: Any of the scientists that we spoke about this morning who may have been involved? Were any [of them] musicians in their own right, as well?
COHN: Well, I spoke [about Paul Shallert, the] guy [with] the eight-foot pole63—he was my first horn. And, you spoke about a double-bass player. We had one fellow who moved into Oak Ridge, in a little tiny house, with his double-bass. (He recently retired as a professor of Biology at Washington University of St. Louis.)

I have a marvelous picture taken of the Oak Ridge Symphony in rehearsal in its first or second year, when the Army was still here, and we had a lot of GIs64 in the orchestra. It's a shot taken down [at] the first violin section, in front of the violas and looking through the conductor, so you see the bowing arm of all the first violins going down, second stand, third stand. The right arm of the first stand, concert master, has three stripes; the right arm of the second stand has two stripes; the right arm of third stand, one stripe.
YUFFEE: Was that because of the ability or…?
COHN: It was strictly ability—the real pecking order.
YUFFEE: Did you ever conduct—
COHN: —[Yes, for 11 years]. I lost most of those [musicians] when the war ended.

The three-stripe sergeant, I heard him once at a rehearsal break fiddling around [with the] Mendelssohn Violin Concerto. I said, "Can you play that?" He said, "Sure: I know it by heart." I say, "Can you play it at a concert?" He said, "Sure: you want it, we play it." So, at the second concert I had a sergeant playing the Mendelssohn Violin Concerto.
YUFFEE: Did you ever end up composing anything?
COHN: Did I ever compose anything? No; I can't even play the piano.
YUFFEE: So, basically you just—
COHN: —I played the cello and I was a conductor until I retired after 11 years. We [have gone] through a series of professional conductors since then. We're on our 11th or 12th right now.
YUFFEE: Obviously, you are still active in it?
COHN: I'm still active in it, but my days are numbered because I lost part of the use of my left arm, which is my fingering arm. I can still get up on the neck [of the cello] and finger [the strings], but I can't get into thumb position because I can't raise this part of my arm. (points to his upper arm) I've had various neuromuscular problems, so I think my days [as a cellist] may be numbered. I still have a 1750 cello in the other room that I play once in a while, and I get [to] rehearsals.
YUFFEE: It looks beautiful.
COHN: You didn't see it.
YUFFEE: I saw the case.
COHN: The cello is sitting out; it was built in 1750. It's worth as much as our grand piano is worth.
YUFFEE: It goes back quite a ways.
FISHER: I didn't realize that instruments lasted that long.
COHN: At the time, the dealer in Paris, where I [studied] for six months, offered me the chance to buy one built 100 years earlier, in 1650. I liked the sound of this one better; it was also less expensive. So I took the 1750 one.
YUFFEE: Seeing it's 1995, I don't think anyone would fault you.

I guess the last question, in closing unless, Fisher, you have any other questions—
FISHER: I was just going to ask a summary-type question.
YUFFEE: Basically, are there any questions that we didn't ask you, that we should have asked you?
COHN: I don't think so. I think I ad-libbed some answers to unanswered questions already—mainly, what I think of the charge of human radiation experiments.
Nuclear Energy Policy and Public Opinion

FISHER: Is there anything else you would like to offer, besides those ad-libs and your comment about Hazel O'Leary, which I swear we will not edit out of the transcript? Is there anything else you'd like to say? This is your opportunity to run the show. We offered up some verbal orchids, but we really wanted you speak about issues that you thought were important and to fill in the gaps in the historical record that publications don't always [fill].
COHN: You asked me about what I consider my most important contributions. I think I mentioned my founding of the orchestra, which is out of the loop, so to speak. But, concerning the nuclear power question, I think the public antipathy that has been raised by certain well-meaning, but misguided people—[the assertion] that there's no reasonable way of handling nuclear waste—is totally off the mark. Waste can be handled in such a way that it will not enter the biosphere65 or harm anybody. Nuclear power is the answer to both the problem of global warming and fossil fuels. I'm a firm believer in nuclear power. I think it has been given a bad rap by people who ought to know better. In other words, I think the waste problem is a technical problem turned into a social problem, which it shouldn't have been. I'm halfway through this book (handing Fisher a book); are you familiar with it?
FISHER: First Nuclear Era by Weinberg. No, I'm not.
COHN: Alvin Weinberg was the Director of Oak Ridge National Lab for [about 20] years. He's been retired for over 10 years. This [is] in his autobiography [of his career] at the Laboratory, along with his general feelings about the whole nuclear enterprise: how it developed and where it's going. The thesis to this book is that we're ending the first nuclear era but there's a second one as soon as people come to their senses and realize that there are safe nuclear reactors and that safe disposal of nuclear waste is feasible.
YUFFEE: One of the issues seems to be that there may be the capability to dispose of nuclear waste safely, but that people aren't willing to commit the funds necessary and that's made it unsafe. Do you think that's a fair assessment?
COHN: You mean a lack of money?
YUFFEE: Or, lack of desire to put enough money into the disposal of nuclear waste.
COHN: I think a large amount of money has been put into it. I mean, the design and the construction of those underground repositories in New Mexico, and the argument about using Yucca Flats66 [in Nevada]. I think that money has been put into those, but as long as you have people who have the public-address system of the news media, saying, "It ain't safe, it's going to leak, it's going to get out, not in my back yard," no amount of money is going to override that. That's a belief in witches, and we've been through that once in our history. It's a superstition, that there's no safe way. After all, the Australians have a safe way, the Swedes have a safe way.67 We've had people working out of Oak Ridge designing a safe way, or safe ways, for a long time. The political will isn't there.
YUFFEE: Maybe sites like Hanford, which have had problems with tanks leaking, and that sort of thing—
COHN: —Yeah, I know, but for every case like that there's a clear answer. Those [tanks] were built during World War II, when materials were at a premium, [making it necessary to build tanks from materials that were too thin or of lower grade]. Naturally those tanks are going to pot. Also, ask, "Where are they leaking to?" They're leaking into clays that surround them, and the clays act like ion-exchange absorbers; so, it doesn't go anywhere once leaked.

So, yes, there were leaks. They won't be repeated. Also, the leaks haven't done any damage, and won't do any damage. The tanks built since then have been built differently, and don't leak. After all, you do learn from experience. The Chernobyl reactor was built along a design that was abandoned in this country decades ago, and what happened there can't happen here.
YUFFEE: And that concludes the interview. Thank you very much for your time. We appreciate your insight and your thoughtful comments and thank you for having us come here and talk to you.


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