Why the LFTR is Still Needed

A new MiT report, The Future of the Nuclear Fuel Cycle, argues that

Uranium supplies will not limit the expansion of nuclear power in the US or around the world for the foreseeable futurer . . .

This should quiet the anti-nuclear power camp on that particular issue, but it won/t. Critics of nuclear power have a tin ear when it comes to evidence. Any evidence that discredits their position simply does not exist, in their minds, and thus they will discount the MiT Report, and continue to tell us that we are running out of uranium.

If we are not running out of uranium is their any justification for the LFTR, a reactor that operates on an alternative - Thorium - fuel cycle? The answer is that there are several good reasons for adopting LFTR technology, even though there may be a large supply of accessible uranium.

One major reason for choosing the LFTR is that it invites far lower fuel cycle related capital investments. If the future reactor fleet is to be entirely uranium fueled, very large capital investments will have to go into uranium mines, processing facilities, enrichment facilities, and spent fuel management. in addition all of these facilities have significant operation costs attached.

Now consider fuel related the capital costs associated with a fluoride salt thorium reactor deployment compared to that of a massive deployment of uranium fueled molten salt reactors. First thorium is a bye product of rare earth mining, and with increasing rare earth use in the economy, more and more thorium will be coming out of the ground anyway. Thus, unlike uranium which is often mined in costly uranium only mines, thorium basically comes out of the earth at no added cost, from mines that would exist whether or not we wanted to recover thorium.

Secondly, while the milling expenses for thorium and uranium would probably be similar, 200 times more uranium would have to be milled, because uranium reactors operate on a once through fuel cycle reactors, which consumes less than 0.5% of the milled uranium, while nearly 100% of the milled thorium will be consumed in closed fuel cycle LFTR.

Secondly, the uranium must be enriched, and this involves another costly, energy intense process. With thorium the enrichment process can be skipped. Following enrichment uranium oxide must be prepared fabricated into reactor fuel pellets. in contrast thorium would be prepared for reactor use by fluoridation, a simple, inexpensive and well understood chemical process. At that point the thorium would be inserted into a reactor blanket where it would be bombarded with neutrons. After thorium absorbs a neutron it is transformed into protactinium 233, which will be separated from the blanket salts by fluoride chemical processes, that will be performed by processing equipment that is directly attached to the reactor. Then the p
rotactinium is stored for a few months, while it undergoes nuclear transformation to fissionable U-233. Once that occurs, the U-233 is automatically inserted into the reactor core by another reactor mechanism. All of these processes are low cost.

The advantage of the Thorium Fuel cycle LFTR is that it requires a fuel infrastructure that is 200 times smaller than a fleet of once through uranium cycle reactors would require. The added cost of the uranium infrastructure is not the primary problem. Rather it is the enormous task of building the infrastructure. The LFTR will require a large infra structure as well, but the infrastructure that will be required to keep LFTRs fueled will be tiny compared to that of a once through uranium fueled reactor fleet.

If we draw the comparison between LFTRs and LWRs, even more U-235 has to be prepared per GWh of power delivered. LWRs waste about 17% of the U-235 that goes into the core, as well as an even larger percentage of the plutonium created in the core. These inefficiencies mean that more U-235 has to be produced relative to the fuel requirements of LFTRs.

LFTRs produce little or no nuclear waste, and indeed can be significant consumers of actinides, which are the most troubling components of LWR nuclear waste. LFTR waste products reach benign levels of radioactivity after 300 years, but many useful and valuable fission products become safe after a few years, and can be mined from the fission product stream for use in industry. Long half life fission products have uses in medicine, and industry. Thus the fission products from LFTRs can be viewed as material resources rather than nuclear waste.

Although Fast Breeder Reactors share many of the advantages of the LFTR, they are likely to be considerably more expensive to build and deploy in large numbers. In addition, FBRs require 10 times the fissile inventory of LFTRs or even more, thus limiting the size of the initial deployment of FBRs. FBR advocates argue that the higher breeding ratio of the FBR will make up for the disadvantage. But it will take time to breed up to the size of an initial LFTR deployment. Supplementing the FBR start up stock with freshly separated U-235 would require the same sort of uranium mining, processing and seperating facilities that would be required by a uranium fueled reactor deployment. Using the nuclear fuel inventory in existing LWR waste stockpiles, more than enough LFTRs could be started to provide 100% of American electricity. If the LFTRs simply replaced the fuel they consumed through nuclear breeding, no further reactors would only be required except to meet added electrical demand.

The LFTR offers both lower cost and significant deployment advantages over the FBR.

Thus the LFTR offers economic and deployment advantages over any of its competitors including Light Water Reactors, Uranium fueled Molten Salt Reactors, and fast breeder reactors. It would be far cheaper to invest in LFTR development and deployment than to build the new uranium mines, mills, isotope separation and fuel fabrications facilities that would be needed to support a uranium fueled reactor deployment. Clearly then even given adequate uranium supplies, the LFTR continues to offer significant advantages for a large scale nuclear deployment.

Understanding Molten Salt Reactors: 1. How are MSRs Different from LFTRs?

The name Molten Salt Reactor (MSR) is more inclusive than the name Liquid Fluoride Thorium Reactor (LFTR). The LFTR is a type of Molten Salt Reactor that features the use fluoride salts and a thorium fuel cycle. Strictly speaking a LFTR need not be designed to produce fuel in a breeding range, but breeding is an important justification for the use of the thorium rather than the uranium fuel cycle.

In chemistry a salt is an ionic compound that is produced when acid undergoes a neutralizing reaction with a base. Some salts are compounds of metallic and non-metallic elements. Salts become molten (or liquid) when heated. Different salts have very different melting temperatures. Some salts may melt at relatively low temperatures, while other salts require several hundred degrees centigrade of heat before they melt. Mixed combinations of salts may melt at a lower temperature than individual salts will melt.

Some molten salts are very good conductors of heat, and some molten salts may not boil until they reach 1400 degrees centigrade, or even higher. These qualities make molten salts potentially excellent coolants for high temperature reactors. Research on high temperature fluoride salt cooled reactors continues at Oak Ridge National Laboratory (ORNL).

Two families of salts have been identified as potentially excellent reactor coolants. They are Fluoride and Chloride salts. Of these two salt families, ORNL scientists quickly chose the former, as presenting fewer developmental challenges while offering greater opportunities for commercial reactor use. Liquid chloride salts were identified as presenting more problems for reactor developers. Chlorine was, in particular, less useful as a neutron moderator than fluorine. However, Chloride salts were suitable for fast reactors, and a Molten Chloride Fast Breeder Reactor was both possible, and probably technologically less challenging than the Liquid Metal Fast Breeder Reactor, as a uranium fuel cycle breeder. In addition, the MCFBR would have offered far fewer safety problems than the LMFBR, while offering a route to technologically superior and lower cost fuel reprocessing.

ORNL Scientists however, also noted that liquid fluoride salt offered a superior performance precisely because of their neutron moderating performance. Moderation removes energy from neutrons. Heavily moderated neutrons are called thermal neutrons, and reactors that are built with large amounts of neutrons moderating materials such as graphite or heavy water are called thermal reactors. Neutron moderation decreases the amount of fissionable material required to sustain a chain reaction, and graphite and heavy water moderated reactors can produce chain reactions with natural uranium. While graphite and heavy water moderated reactors are useful tools for the production of plutonium, they are not particularly efficient tools for burning Pu-239 or even U-235 as nuclear fuels. However, it is possible to breed thorium in thermal reactors. Thermal reactor breeding of thorium offers significant advantages over fast reactor breeding of U-238. Thermal Reactors can operate with 10% perhaps as little as 3% of the fissionable material required to operate fast reactors. Thus thermal reactors can potentially be started at a far more rapid rate than fast reactors.

Fast reactor advocates claim that it is possible for fast reactors to breed at a much more rapid rate, but there appear to be safety problems involved in more rapid fast reactor breeding, and current documented advanced fast reactor designs appear to breed at a similar rate to thermal thorium breeding molten salt reactors.

The term breeding refers to the production more nuclear fuel than is used in a nuclear reactor. If a fertile material, either uranium 238 or thorium 232, is included with the fissionable material placed inside a reactor core along, the result will almost inevitably be the conversion of some of that fertile material into a fissionable material. In the case of thorium, a thorium 232 atom inside the reactor can absorb a neutron, and then becomes a thorium 233 atom. The nucleus, that is the center, of a thorium 233 atom is unstable. A neutron in the unstable Th 233 atom will eventually emit an electron, changing the neutron to a proton, the new proton in turn converts the atom to protactinium 233, and Pa 233 is also unstable. After a few days, a Pa neutron emits an electron, and as a consequence converts to a proton. The added proton makes the atom uranium 233. U 233 is fissionable, and can be used as reactor fuel.

The uranium fuel cycle is similar. If an U-238 atom absorbs a neutron a process that is similar to the process we find with thorium 233 occurs, and the U-239 atom is converted into plutonium 239.

Most reactors produce added nuclear fuel by converting U-238 into Pu-239. The amount of plutonium produced usually equals somewhere in the neighborhood of 60% of the amount of U-235 burned in a conventional reactor. Neither U-235 nor Pu-239 are ideal nuclear fuels at conventional neutron speed. WASH-1097 states

From a nuclear standpoint, the use of U-233 in a thermal reactor makes it possible to achieve higher fuel conversion ratios and longer fuel burnups than is practical with either U-235 or Pu-239. . .

The higher conversion ratios which can be obtained in thermal-spectrum reactors when using U- 233 instead of Pu-239 can result in a significantly better utilization of natural uranium fuel resources with thorium-fueled reactors than with the low-enrichment, light-water cooled uranium-fueled reactors . . .

WASH-1097 defines the fuel conversion ratio,

The fuel conversion ratio (CR) is the ratio of the amount of fissile fuel produced per unit of fissile fuel destroyed. . .

Breeding takes place when the conversion ration is greater than 1 to 1. While plutonium theoretically produces more neutrons and therefore faster breeding in fast reactors,

A higher breeding ratio can be obtained with Pu-239 than with U-233 in a very high-energy, fast- neutron spectrum reactor. On the other hand, in a degraded (10 to 100 keV) fast spectrum, U-233 would probably be as good as, or better than, Pu-239. Also, the variation of U-233 and Pu-239 cross sections with energy are such that improved reactivity coefficients would be obtained with the use of U-233 in a large sodium-cooled FBR. This leads to improved nuclear safety characteristics. . . .

The energy dependence of the fast-fission cross sections of Th-232 and U-238 is such that the use of Th-232 would produce an improved reactivity coefficient in a liquid-metal-cooled FBR. The fast fission cross-section of Th-232 is much lower than that of U-238 so that use of the latter leads to much larger conversion ratios in fast-spectrum reactors.

Thus not only is thorium breeding attractive in molten salt reactors, thorium breeding in fast reactors enhances their safety, and increases their conversion ratios. This point has not been lost on Indian reactor scientists who plan large scale production of thorium-uranium fast reactor breeding hybrids. Breeding thorium as a nuclear fuel in fast reactors would produce a large amount of fissionable U-233 that can be used as nuclear fuel in conventional reactors. This point has not been lost on Indian nuclear scientists, who plan to use the extra U-233 in Advanced Heavy Water Reactors. U-233 fueled non-breeder or converter Molten Salt Reactors offer attractive, safer and lower cost alternatives to conventional water cooled reactors, while reducing but not eliminating the nuclear waste problem. Thus, a modified Indian system could be developed, that would feature thorium breeding in IFRs, with U-233 burning MSRs. The rub for such a system would be that LFTRs would be cheaper to develop, cheaper to build, safer and cheaper to operate, and would virtually eliminate the nuclear waste problem.

The LFTR then is a thorium breeding MSR, that offers what may well be the simplest and best solution to the problem of producing sustainable nuclear power.

Radon as harbinger of a cornucopia

Map of Natural Radioactivity in the United States
Joe Romm recently offered an interesting post on growing concerns about the environmental impact of fracking as a natural gas production method. I have been calling Joe's attention to the problem created by radioactive radon in the natural gas produced by fracking (hydrolic fracturing) of gas containing shale. There are dozens of radioactive waste cleanup sites in Texas, associated with the natural gas industry. The natural gas industry has largely kept the Texas radon problem largely hushed up. But elsewhere the problems are becoming increasingly well known.

A November 2009 story in Pro-Publica, titled Is New York’s Marcellus Shale Too Hot to Handle states,

The information comes from New York's Department of Environmental Conservation, which analyzed 13 samples of wastewater brought thousands of feet to the surface from drilling and found that they contain levels of radium-226, a derivative of uranium, as high as 267 times the limit safe for discharge into the environment and thousands of times the limit safe for people to drink.

Not only is unsafe levels of radon coming up with water used in the fracking process, but it is also coming up with natural gas, and flowing into peoples homes through natural gas pipelines.According to the physics department of Idaho State University, Natural gas in the home is believed to produce an annual exposure of 9 mrem per year, while average home exposure to radiation from nuclear power plants is almost 100 times less dangerous. Amazingly, environmentalist who claim to be concerned about radiation problems related to nuclear power have ignored the radiation problems caused by natural gas, even though they are potentially far more deadly. Anti-nuclear organizations like the Sierra Club and Greenpeace advocate putting more, rather than less highly radioactive natural gas into peoples homes, while opposing nuclear power which has been shown to pose far less radiation dangers than natural gas does, the New York state evidence suggests that natural gas produced by fraking may be much more dangerous than ordinary natural gas.

So where does the radon that seems to appear every time shalr rock formations are farked for natural gas, come from? According to a report from Commonwealth of Kentucky Geological Survey,

radioactive minreals uranium, radon, and thorium . . . occur in the black shale, which crops out in a horseshoe shape around central Kentucky, and in the phosphate deposits in the Lexington Limestone in central Kentucky.

The black shale is a marine, organic shale that contains many different kinds of minerals, including phosphates. The outcrop of the shale is extensive, and the high organic content makes the shale a good host for radioactive minerals. Uranium and thorium occur in the shale, and radon is a daughter product of the uranium in phosphates within the shale. The black shale also occurs in the subsurface in eastern and western Kentucky where it comes into contact with groundwater. In some areas of the state where there has been significant oil drilling, casing and pipes have become radioactively contaminated, which could cause secondary health hazards when humans come into contact with this drilling equipment.

So it is clear that the presence of radon indicates the presence of uranium and/or thorium, and since radon has no other natural source, finding a lot of radon, enough to be dangerous means that a lot of uranium and/or thorium must be around.

In situ mining is a very old technology. Copper has been mined in situ for at least 1000 years and quite possibly for 2000 years in China. In order to mine in situ. a leaching solution is pumped through resource baring permeable rocks. The resource mineral or minerals are dissolved in the leach solution and then pumped to the surface. Many uranium mines now use in situ leaching technologies as a means of uranium recovery.

From the viewpoint of energy investment, in situ mining has a big advantage over the pick and shovel type traditional mining. Yes I know, they don't use picks and shovels any more, but they still dig, and pull large amounts of material out of the earth. Digging and pulling material out of the ground, and then milling it, and disposing of the waste is energy intensive, especially when you are dealing with low grade ore. In situ mining, however, is not energy intense. Thus so called low grade ores can be mined by in situ mining without huge energy costs. There are of course challenges with approach. A major limitation to the in situ approach would seem to be that while there is a whole lot of uranium and thorium locked up in shale rock, shale is not permeable, and thus not currently seen as a candidate for in situ mining. That is where frarking comes in.

What a fracking does is to fracture shale and other rocks, that is to make them permeable. So it is possible to frake uranium/thorium baring shale, and then mine them in situ? Why not? We are not looking for a technological break through, just the wedding of two proven technologies. That looks like a slame dunk.

There is no reason why granite could not be also mined for minerals in sutu, and fracking has been used to mine granite already. Still, I suspect that a whole lot more research would be required on fracking granite before the fracking/in situ technology would be used, but the research hardly need take a long time, and fracking/in situ mining of granite can yield enormous amounts of Uranium and thorium plus many valuable metals and other minerals.

Among the common elements often found in shale in recoverable amounts are , vnadium, magnesium, copper, chromium, zinc, nickel, iron, aluminum and phosphorus.

if you would like to confirm the presence of Uranium and/or thorium an granite, there is a simple experiment that you could perform. Take a Geiger counter to a cemetery, and start checking granite tombstones for radiation. Some, although not all will show up as radioactive. The same thing will be true for granite in public building and countertops. In addition to thorium and uranium many granites contain recoverable amounts of Tantalum, Niobium. Titanium, Zirconium, Hafnium. and Yttrium, beryllium, and other rare earths. Clearly then the in situ mining of granites for actinides would yield a wealth of other mineral riches.

Let us now take a look at the big picture. The world Thorium and Uranium is for all practical purposes a sustainable energy resource. They can be mined from shale with very favorable energy return on energy Invested (EROEI). In addition to uranium and thorium a number of valuable minerals can be recovered in the same mining process with little to no further energy investment. Uranium and thorium recovery is also possible through in situ mining of some granite with a favorable EROEI. Many valuable minerals could also be recovered from the granite along with uranium and thorium with little to no further energy investment,

These findings are inconsistent with the neo-Malthusian view that we will soon run out of mineral resources. Indeed my conclusion is that the world can continue to supply abundant energy and material resources that will not be exhausted for as long as people live on it.

Children of the Club of Rome

Sarah Palin's story that Obama's health care legislation called for death panels to determine who would receive medical care, and who would simply be allowed to die in the new medical order, has rightly been described as the lie of the year for 2009. However, a recent post on the Oil Drum by Megan Quinn Bachman tells us that a form of death panels is emerging among people who believe that the Ehrlich/Forrester/Meadows/Club of Rome theory of global collapse of industrial civilization/resources/population . The post, titled "Leading the Way to a Low-Energy Future" describes what Bachman calls lifestyle leaders. Lifestyle leaders are people who are

building gardens, weatherizing their homes, getting rid of their cars, moving off-grid, bartering with neighbors and joining Community Supported Agriculture (CSA)

According to Bachman these lifestyle leaders are pioneering the new order by forging a new set of careers appropriate to the new post civilization order:

I would argue that these people, the Children of the Club of Rome, are the death panels for hundreds of millions if not billions of people. Yet the Club of Rome model predicts a mass human die off:

Thus Bachman's lifestyle leaders are preparing for a Club of Rome apocalypse, which features mass human die off.
I am fond of Gail the Actuary (Gail E. Tverberg), an Oil Drum Editor who is associated with the "we are headed for collapse" point of view. i see Gail's work as having a positive aspect in that she and her guest posters repeatedly point to problems which are otherwise unvoiced. i do disagree with some assumptions and with the chain of argument which inevitably leads to negative conclusions about the future of a high population, materially wealthy civilization. I disagree with the view that the collapse of material civilization is inevitable. In addition I view the projected collapse of material civilization as an unmitigated catastrophe. This is what Chris Clugston suggests:

i disagree with this perspective because it assumes a far more limited future resource picture than I do. My viewpoint can be stated simply, we are not running out of energy, material resources, or food. A combination of two technologies, Hydraulic Fracturing (fracking), and in-situ leaching, offers the potential for high material resource recovery with favorable EROEI, from what was previously considered low grade ore. It is inevitable that the use of such recovery technologies will be applied to resource recovery, and the recovery of Uranium and thorium as part of the process will assure a favorable EROEI. Both fracking and in-situ leaching are highly tested technologies and thus appear to offer a path to a continuation of high energy/high material output civilization. Through the use of efficient and safe technologies like the Liquid Fluoride Thorium Reactor, the population of earth can be assured of a high level of material prosperity for as long as there is likely to be people around.

Thus the future resource picture may not be nearly as bleak as Gail the Actuary and her associates would have us believe. Nor is the supposed mega-famine, which Paul Ehrlich, Jay Forrester and the Club of Rome have predicted, nearly as likely to occur, as they suggest. Ehrlich's famine predictions were thwarted by the so called "Green Revolution," which dramatically increased agricultural yields in countries like India.

A recent review of global agricultural resources, published in Science, titled "Food Security: The Challenge of Feeding 9 Billion People." argues,

the world can produce more food and can ensure that it is used more efficiently and equitably. A multifaceted and linked global strategy is needed to ensure sustainable and equitable food security, . . ..

Thus in a high energy uranium/thorium based economy, the food supply is likely to be continue to be assured. The argument for the inevitable collapse of civilization can be falsified with some certainty, the impending image of mass death through the starvation of most people can be written off as a fantasy. Bachman's "lifestyle leaders"can be seen for what they are, a misanthropic death panel for the human race, whose lifestyle will turn against them as the population of earth continues to survive and increasingly prosper.

AXIL on Controlling Nuclear Proliferation

The discussion on the Energy from Thorium Discussion Forum is beginning to become an important contribution to the current discussion of energy on the Internet. Many of the discussions conducted on the Energy from Thorium Discussion Forum pages are conducted at a very high level, and worthy of being known outside the small EfT circle. This is most certainly the case for the currently excellent discussion of Nuclear Proliferation control issues.Since I have a blanket permission from AXIL to use his comments in my posts I will offer some quotes from his comments to illustrate why readers who are aware of the importance of the proliferation issue in the future of world energy should read this discussion.

Axil wrote:

In a nut shell, what Holden and his associates in the administration want to keep out of the hands of the proverbial rogue nation is highly enriched uranium, plutonium, reprocessing and enrichment.

In order to entice non-nuclear nations to abide by these restrictions, these nations are provided nuclear fuel or even small sealed reactors at no or low cost in exchange for spent fuel or decommissioned small reactors. This is guaranteed to all signatories to the non proliferation treaty by an international fuel agency that can not use access to nuclear power as leverage in political situations.

The goal is to remove the need for the rogue nation from developing a nuclear infrastructure and a large trained nuclear work force that could be used to develop nuclear weapons on the side and in the dark of night.

By so decoupling nuclear power from the ability to produce nuclear weapons, any nation that persists in acquiring and independent nuclear capability must by doing it to develop nuclear weapons.

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The NPT was conceived during the cold war. The current cooperation between the nuclear powers including Russia is a powerful facilitator to the internationalization of nuclear power.

One of the rights that a signatory nation currently has is the right to enrich Uranium. The US wants to remove this ability from the NPT participants. As a participant of the NPT, Iran has the right to enrich uranium. Iran has taught the US some lessons about the shortcomings of the existing NPT.

This current thinking on nuclear power still divides the world into nations that are fully nuclear capable and those that are not; this could be a fatal flaw in the new international fuel strategy.

Let us hope that the first world has matured and can control their use of power at least in regards to the international use of nuclear fuel. The main question is as follows: “are the current nuclear powers willing to cede their monopoly of nuclear power to the rest of the world”? The alternative is that tens of nations could produce bomb grade material and have the knowhow to construct a device with the number increasing each year.

Solving this dilemma is and important step in combating global warming.

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Thorium breeding is the possible technical solution to the nuclear proliferation dilemma as follows.

Uranium use would be phased out along with it associated fuel reprocessing or enrichment.

If nuclear power production is decoupled from nuclear weapons production by eliminating the uranium fuel cycle and uranium mining, reprocessing and enrichment, this would free nuclear power to grow unimpeded by proliferation fears.

Besides making the production of a plutonium bomb far more difficult, weapons would have nothing to do with nuclear power. Thorium would be the nuclear power paradigm. Uranium would be the nuclear weapons paradigm.

The technical challenge is to make thorium fuel in the form of pebbles near proliferation proof.

If a nation runs a thorium once through deep burn (<90%)> A blanket pebble is a ceramic coated graphite ball containing only a small amount of fertile thorium each. They are breed to contain fissile U233 in the blanket region of the reactor to form seed pebbles which support the nuclear reaction. The blanket pebbles can be spiked with Th230 to produce additional U232. The U233 content can also be easily denatured by dumping in some U238 (20%) to denature the thorium is the blanket pebbles. There is no such process available for denaturing plutonium..

A large number of seed pebbles (in the hundreds of thousands) would be required to construct a nuclear device enabled through U233 enrichment. Even a diversion of a small number of seed pebbles would cause a subcritical shut down the reactor. Reprocessing/enriching of U233 does not currently exit and would require a huge research and deployment effort by the proliferator.

Very little or a trace amount of PU239 (.001 of the amount contained in LWR waste) is present in the spent pebbles and the Pu238 would make it difficult for weapons construction.

The waste in the pebbles would be short lived (cooled in a few hundred years) and not capable of use in weapons development at any stage. The most long lived waste would be carbon 14 which can be sequestered by absorption in certain minerals at the bottom of a bore hole. Would this work?

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If nuclear power production is decoupled from nuclear weapons production by eliminating the uranium fuel cycle and uranium mining, reprocessing and enrichment, this would free nuclear power to grow unimpeded by proliferation fears.

Besides making the production of a plutonium bomb far more difficult, weapons would have nothing to do with nuclear power. Thorium would be the nuclear power paradigm. Uranium would be the nuclear weapons paradigm.

The only thing remaining is to make the seed thorium pebbles near proliferation proof; simple.

As I indicated there are other, equally worthwhile comments that I do not have permission to quote.

The transformative potential of nuclear power or a cruel hoax?

The title of Michael Tobis's post on the Energy Collective today tells the story, The Cruel Hoax: Growth and Equity Cannot be Sustained Tobis tells us. Tobis claims:

the 2.5 % growth for 50 years amounts to a 3.4 fold increase in wealth for us. If the population does not increase, that means the 11-fold increase in the prior calculation (for others to catch up only to 2008 levels in the west) has to be multiplied by 3.4 to catch up to the west, plus another factor of 1.4 to account for the increased population.

As a consequence, the impact per unit of wealth has to decline by a factor of 11 * 3.4 * 1.4 = 52.9 .

In order to support business as usual without increasing net impact or abandoning any claim to international equity, impact per unit wealth has to decrease by more than a factor of fifty. Even that may not be sustainable: that is what is needed to fulfill the implicit promise of a growth economy to the rest of the world for another fifty years without increasing the RATE at which the earth is damaged. And even so, the growth idea implies continuing reduction in impact per unit of wealth thereafter.

Contrary to Tobis, from the viewpoint of energy, the long-term economic growth of the human economy is sustainable. The largest single terrestrial energy source remains completely untapped, while 99% of the second largest potential energy source is now wasted. The potential energy from these sources would be great enough to sustain the entire current population of the Earth at Western European levels of energy consumption for hundreds of millions of years. The energy sources are thorium and uranium, and every year enough energy from both are thrown away, to sustain the entire planet at energy levels that Mr. Tobis seems to think are impossible to sustain. While the use of oil as an energy source is not sustainable, the use of thorium and uranium can be and they can be substituted for oil as an energy source.

In 2007 Sparton Resources Inc., investigated fly ash samples taken from the Ajka Power Station in west- central Hungary. It was reported that a 20 million ton ash pile contained between 92 and 154 parts per million U3O8 (yellowcake). U2O8 is recoverable from fly ash using low energy, low cost recovery technology. Assuming that 0.1 pound of uranium is recoverable from every ton of fly ash, this means that 1000 tons of uranium could be recoverable from the Ajka ash pile. If efficient energy extraction technology were use to extract the energy from the 1000 tons of uranium, it could run 1000 nuclear power plants for a year. Those power plants would produce 2 and a half times the electricity now produced in the United States during a single year. Sparton did not even bother to assess the amount of thorium in the Ajka ash pile, but we can presume that if the average proportion between uranium and thorium holds, there would have been enough thorium to power another 3000 large reactors for a year. 3000 reactors would produce enough electricity to supply the entire population of India at near American levels of electrical consumption for a year.

It should not be assumed that it would be impossibly expensive to extract electricity from uranium and thorium. India is building a commercial fast breeder reactor that it expects to be finished by 2013. The technology has already been tested an earlier small prototype. The new Indian reactor will efficiently extract 100% of the energy from uranium at a cost of six and a half cents per kWh. Later serial produced Indian fast breeders are expected to produce electricity at a cost of four cents per kWh.

I have argued that Liquid Fluoride Thorium Reactors, capable of efficiently extracting 98% of the energy in Thorium, could be manufactured in factories at a cost as low as one dollar a watt of generating capacity. I might be wrong about this cost estimate, but so far no one had demonstrated that my estimate is impossible.

The ability to produce abundant, low costs energy is the key to maintaining human material well-being. When I was a young man, considerable concerned was expressed because human society faced a shortage of mercury. "How can human society survive, once the mercury runs out," people wondered. Yet substitutes were found. Mercury no longer goes into thermometers, but people still get their temperature checked.

The Indian government has already paid for the development of the fast breeder nuclear technology that will allow for low cost efficient conversion of uranium and thorium into electricity in India. The Indians estimate that building their fast breeder reactors will cost about $1.20 per watt of electrical generating capacity. This is almost half the capital cost of wind generators in the United States. If the Indians can build reliable post-carbon generating capacity at $1.20 per watt, a lot of electricity and energy intensive industries is going to relocate to India during the next 40 to 50 years. The same Indian technology that lowers power costs with use uranium and thorium several hundred time more efficiently, than uranium is used in current nuclear technology.

A lot of now poor Indians are going to see revolutionary changes in their standard of living and quality of life in the next fifty years. The future material prosperity of India is not a hoax. I can only conclude that Michael Tobis simply does not understand the potential of nuclear power.

Light Water Reactor EROEI

Alvin Weinberg invented and patented the Light Water Reactor. My father made an important contribution to its development. Both Dr. Weinberg and my father, like other scientist they worked with, never regarded the LWR as the best way to make nuclear power.

Light Water Reactors are not very efficient producers of energy. Although potentially 100% of uranium could be either burned as nuclear fuel, or converted to nuclear fuel, only a tiny fraction, less than 1% of the energy locked in uranium is released inside light water reactors. U-235 is the primary fuel of light water reactors, and only 0.7% of natural Uranium is U-235. Because the normal hydrogen in light water tends to consume non-trivial amounts of neutrons in reactors, the U-235 content of nuclear fuel has to be increased to 3% or even 5% of the reactor uranium. The enrichment process requires large amounts of energy.

First, because of the nature of the uranium enrichment process, nearly 30% of the U-235 present in natural uranium does not get included in the enrichment product. So 30% of the potential energy of the U-235 present in natural uranium never makes it to a reactor. Some breeding of U-238 takes place in inside a reactor. The result close to 3% of the U-238 is converted into reactor-grade plutonium. Now reactor-grade plutonium is not very good nuclear fuel in a thermal-spectrum reactor. It does not burn well in LWRs, and when the reactivity of the fuel can no longer support a chain reaction inside a light water reactor, nearly 20% of it is left. Another 12% 27% of the original U-235 is left.

Thus light-water reactors only extract about 0.6% of the energy present in natural uranium. The rest of the energy goes into two piles. One marked “Depleted Uranium”, and the other marked “spent reactor fuel”. “Spent reactor fuel”, ironically contains about as much U-235 as natural uranium. The system of electrical generation in Light Water Reactors is to place the reactor inside a high-pressure vessel, heat water with it, turn the hot water into steam (in a BWR) or use the hot water to make steam (in a PWR), and run a turbine with it. The turbine then turns a generator, which produces electricity. This whole, rather complicated system only turns about 1/3rd of the heat produced in a LWR into electricity. Thus 70% of the energy captured by the reactor is lost as waste heat. So of the energy present in natural uranium, 0.2% gets converted into electricity, 99.8% of the energy gets lost.

The light-water reactor system is extraordinarily wasteful in terms of energy. It is also wasteful in terms of uranium. In order to make LWR fuel, 200 pounds of natural uranium gets depleted. 19 pounds of that uranium can go back into a reactor, so over 90% of mined uranium never goes into a reactor. Of those 19 pounds of depleted uranium – almost all U-238 – that goes into a reactor, 18 ½ pounds comes out unchanged. Such is the power generated by splitting the atom, that by using only a very small amount of its potential energy, very useful work gets done.

It is a measure of the inefficiency of light-water reactors, that its “spent fuel” can be removed, remanufactured without changing the fuel ration, and placed in other types of reactors – say the heavy water CANDU reactor, and used like ordinary CANDU nuclear fuel in electrical power generation. But even the CANDU reactor is still not very efficient. For every 200 pounds of uranium used in a CANDU reactor, about 1.4 pounds actually generates energy or about 0.7% of the energy in natural uranium. From the viewpoint of EROEI (energy returned on energy invested), the CANDU reactor is a better deal than light-water reactors. First because uranium does not have to be enriched before it goes into CANDU reactors. And secondly, because the CANDU is a little better at extracting energy from uranium than light-water reactors.

It is clear then that the light-water reactor, a technology that was advanced in the late 1940's and early 1950's primarily for military use, is very inefficient at the task of extracting energy from uranium, and converting it into electricity. Only 0.2%, that is one five hundredth (1/500) of the energy that could potentially be liberated from uranium by the nuclear process, is converted into electricity by the light-water reactor. The liquid-fluoride thorium reactor (LFTR) can do much better than this.

The Uranium Fuel Cycle

WASH-1097 remains an invaluable source of information on the thorium fuel cycle. It explains why the thorium fuel cycle creates such a small problem with transuranium isotope. First, however, it is important to understand why there is a problem in the uranium fuel cycle.

When U238 absorbs a neutron a transformation process is triggered. After a couple of sub-nuclear events (beta radiation), the two neutrons in the atom become protons. This process turns the uranium-239 atom into plutonium-239. Pu239 is fissile. But Pu239 has some characteristics that make it something less than a desirable fuel, in ordinary moderated thermal neutron reactors. Fission is most likely to occur with low energy neutrons. Yet, Pu239 has a healthy appetite for these low energy neutrons, while only fissions about 2 times out of 3 when it absorbs low energy neutrons. The net effect is that Pu239 doesn't "pull its weight" in the reactor when it is fissioned by low-energy neutrons. It doesn't produce enough neutrons per absorption to make up for the neutrons lost in absorption.

In the ideal uranium fuel cycle, a Pu239 nucleus absorbs a neutron, splits and emits three neutrons. One of them is absorbed by another fissile atom (U235 or Pu239) atom which splits. The other is absorbed by a U238 atom which is transformed into U239. As you get more and more of the absorption products of Pu239 building up in the nuclear fuel (Pu240, Pu241, etc), the neutronics become more and more unfavorable.

The heart of the problem is the fact that low energy neutrons split Pu239 atoms only about 2/3rds of the time. This is all laid out very nicely in WASH-1097. In the other 1/3rd of the time, Pu239 becomes Pu240. If Pu240 absorbs a neutron it becomes Pu241 and if Pu241 absorbs a neutron, 75% of the time it fissions. Thus by the WASH-1097 account, 25% of the time when Pu 241 absorbs a neutron it becomes Pu242. Thus after absorbing 4 neutrons, nearly 9% the atoms that started out as U238 are still plutonium. This is what is called a poor neutron economy. The neutron economy of fast breeders is better, because a neutron absorption in Pu239 is more likely to cause a fission with more energetic neutrons. Hence the desirability of fast breeder reactors in a transuranium reactor economy.

As we have seen conventional fast breeders use sodium as a coolant, and sodium is really nasty, dangerous stuff. In addition, as Kirk Sorensen points out, using liquid sodium as a coolant, limits the thermal efficiency of a reactor. Thus not only are LMFB reactors inherently dangerous, they
are also not as efficient as power producers as liquid fluoride reactors.

But here we must ask, why are we producing plutonium in breeder reactors? If we are producing it to go into conventional reactors, we are not producing very good nuclear fuel.

- Charles Barton

Uranium or thorium?

I have just argued in my last post that the world's supply of Uranium is virtually limitless. There are estimates that the world supply of thorium is three to four times as plentiful as the supply of Uranium. Both U238 and thorium 232 can serves as a basis for a future energy supplies. It is clear that both thorium and uranium can be tapped for far more energy than the current generation ofd light water reactors produce. Currently light water reactors extract 1% of the energy present that could be produced by natural uranium. It then converts a little less than a third of that energy into electricity. Thus the Light Water Reactor has a 0.3% overall efficiency in capturing energy from uranium, and converting it into electricity. A metal Liquid Fluoride Thorium Reactor can capture 100% of the energy of thorium and convert 45% of it into electricity. A carbon-carbon can potentially convert up to 60% of the energy in Thorium into electricity. Thus a LFTR can be 200 times more fuel efficient than a LWR.

There are uranium cycle reactors that are potentially efficient as the LFTR, but only one type of uranium fuel cycle reactor approaches the many other advantages of the LFTR. The LFTR is extremely sage. The LFTR is a molten-salt reactors. The safety features of MSRs is discussed in a paper by Uri Gat, and H.L. Dodds.

They record the following safety features:

* Simple reactor structure

* Continuous removal of fission products

* A high negative reactivity temperature coefficient that slows down chain reaction as reactor temperature rises

* The LFTR can be self-controlling

* No externally operated controls are required

* Safety can be passive

* Safety is inherent and safety features cannot be altered by tampering, and are thus fool proof

* Ultimate shut-down is accomplished by draining the liquid fuel from the reactor core

* A drain plug can be operated automatically by using a material that melts when the reactor reaches an undesirable heat level

* Core dranaged powered by gravity

* The drain container can be in a shape that prevents drained fuel from become critical

The Fluoride salt coolant is safe because:

* It does not react with water or air

* There is no fire or explosion hazards

* It is non-corrosive with respect to very desirable and suitable structural materials like carbon based materials

* They are stable to high temperatures and exert low pressure

* Liquid salts are often used in industry as heat transfer media for their inertness and safety

* In the event of an accidental spill, liquid salt freezes in place without spreading

* A core meltdown is not a problem, because the fuel is already a liquid

* Since the coolant is also the fuel, a loss of coolant accident is does not lead to fuel overheating

Clearly then the LFTR gas numerous safety advantages when compared to uranium cycle reactors.

A second advantage of the LFTR was its superior fuel processing capacity for fuel processing. Xenon, a highly radioactive gas, that poisons nuclear reactions, can be continuously stripped from the LFTR. From a safety viewpoint this means that Xenon will not escape from the reactor in the event of an accident. From an fuel economy viewpoint, this means that the reactor will transform thorium into fissionable U233 more efficiently. Other undesirable gases and fission products can be removed from liquid fluoride salts.

The LFTR produces only one fissionable U233 atom for every atom it burns. Thus if it was decided to remove U233 from the reactor in order to produce atomic bombs, this would immediately lead to reactor shutdown, since the reactor could not opperate without its fuel. In addition along with U233, highly radioactive U232 is produced in the thorium fuel cycle. U232 considered to be so dangerous, that it constitutes a major barrier to nuclear proliferation with U233. Therefor the LFTR is proliferation resistant.

The LFTR does not produce nuclear waste. Most thorium byproducts fyel cycle byproducts have short half lives, and thus are quickly cease to be radioactive. Most stable byproducts are materials that are useful to industry. Fissionable byproducts remain inn the reactor till burned. Virtually no transuranium elements are produced in the thorium fuel cycle. Thus once nuclear byproducts become stable non-radioactive materials the can be seperated and processed for industrial use.

Thus LFTRs are safe, 200 times more efficient than LWRs, proliferation resistant and does not produce nuclear waste. In addition continuous chemical processing of the reactor fuel eliminates the need for expensice secondary fuel reprocessing plants. Thus the Thoriun cycle reactor possess enormous advantages over the light water reactor.

Phosphate and phosphate tailings

This is a picture of raw materials for a Liquid Fluoride Thorium Reactors. It is also the picture of a significant radiation hazard. 

Phosphate mining tailings contain large amounts of recoverable fluoride, and significant amounts of recoverable uranium and thorium. Phosphate or can be so radioactive that it poses a radiation hazard to milling workers. Not all uranium and thorium is extracted in the phosphate milling process, and phosphate fertiliser contain significant amounts of uranium and thorium along with radioactive decay products. Ground water can become polluted by uranium and thorium from phosphate fertiliser, and phosphate tailings. Even more startling organic food growers are allowed to treat their fields with the raw, unprocessed phosphate tailings once every six years, without any prior extraction of uranium, thorium or radioactive daughter products. Not only can uranium and thorium enter ground water through phosphate fertiliser, but some authorities believe that Polonium 210 a daughter product present in phosphate fertiliser can become concentrated in plants like tobacco, and can be a significant source of tobacco related cancer.

Polonium 210 os extremely toxic and is believed to have been the poison used in the 2006 London murder of Alexander Litvinenko, a Russian dissident.

Phosphate tailings are considered so radioactive that they are not allowed to be used for wall-board filler or for road bed construction in the US and Canada.

The extraction of Uranium and Thorium from Phosphate ore and old phosphate mine tailings would make a large contribution to the elimination of significant radiation problems, as well as the elimination of toxic pollution of ground water.

A hat tip to Owen T. 

World Uranium and Thorium Supplies

Today nuclear power offers large quantities of electricity that is cleaner than coal, cheaper than natural gas and more reliable than wind. Yet critics of nuclear power continue to allege that we are fast running out of uranium resources. .

Earl, Deffeyes & MacGregor in “World Uranium resources” Scientific American, Vol 242, No 1, January 1980, pp. 66-76, estimated world uranium resources. Although this paper does not appear to be online, their data can be found here.

Information about the uranium supply can be found here:

James Hopf discusses the uranium supply here.

The World Nuclear Association has issued a possition paper on Uranium Sustainability which states: The uranium resource is sustainable, with adequate known resources being continuously replenished at least as fast as they are being used. The essential dynamic is the strength of market forces when the market is constantly evolving through advances in human knowledge and the technologies of exploration, mining, and resource utilisation. Depletion of today’s known uranium resources will be more than counterbalanced by replenishment from new discoveries, technical progress and possible substitution.

In addition, a huge increase in efficiency is readily possible through the technological step to fast neutron reactors. This option – unique among mineral resources – offers the nuclear industry a special kind of insurance against future resource shortage.

It may therefore be fairly concluded that uranium supplies will be more than adequate to fuel foreseeable expansions of nuclear power. Indeed, in addition to its other noteworthy virtues, An abundant fuel resource will remain a crucial advantage of nuclear power.

The world faces many challenges in achieving a global expansion of nuclear energy to fully realize the technology’s clean-energy potential. A limited supply of uranium resources is not among them.

In fact Uranium resources from conventional sources compare very favourably with most other resources. Virtually no exploration for conventional uranium sources has been undertaken during the last 30 years. Most of the world’s land surface has yet to be explored for uranium. It is economically possible to extract uranium and thorium from phosphate ore and mine tailings, but this is not done because of the abundance of conventional supplies. This source alone amounts to millions of tons of both uranium and thorium.

For example Chattanooga shale of Tennessee contains about t 6 million tons of recoverable U3O8.

The Conway granite of New Hampshire;contains uranium and thorium deposits estimated to be of the order of tens of millions of tons.

Other unconventional sources of uranium include coal fly ash which contains significant amounts of uranium and thorium, and sea water.

The Japanese have demonstrated that it is technically economically possible to extract Uranium from sea water using low energy techniques.

For discussions see here,
and here.

There has been virtually no world wide exploration for Thorium, because there is no market for it. Standard references on Thorium state: “Present knowledge of the distribution of Thorium resources is poor because of the relatively low-key exploration efforts arising out of insignificant demand.” Still 2005 IAEA-NEA “Red Book” reported a probable Thorium reserve of of 4.5 million tons, but also acknowledge that there was insufficient data for much of the world to even estimate Thorium reserves. An Australian government reports states “The potential for thorium resources, particularly in types of deposits other than placer, is underexploredin Australia". Yet Australia has the largest reported thorium reserve in the world. Thorium is known to be 3 to 4 times as common on the surface of the earth as uranium. The current known thorium reserve of India could supply all of the electrical energy at the rate India now users for 300 years. Current Indian estimates place the Indian thorium reserves at between 3,60,000 and 5,18,000 tons. Indian scientists argue that "the potential of other resources like gas, oil, wind, solar and biomass is very limited." Yet solar energy advocate, D. Yogi Goswami claims that Thorium reserves are too limited to to permit a thorium economy.

The argument that we are running out of Uranium/Thorium resources, amounts to an appeal to ignorance, since you are arguing in effect that undiscovered resources do not exist, and that textbook accounts of proven reserves are always the end of the matter.

Currently uranium market prices are depressed by the effort of the US government to burn up the U235 and Pu239 left over from cold war weapons. Until that stock is drawn down their is virtually no need for new uranium. The only US uranium enrichment plant currently in operation, operates at far less than full capacity. In fact. it only operates at all because a US government owned utility, TVA buys enriched U235 from it. This arrangement has probably been made for national defense purposes. Until the weapons stockpiles are burned up, there is no incentive for more uranium or thorium explorations.

Will the Uranium ever run out?

Imagine a business, that is quite literally running out the ear with raw materials. So much so, that no one has bothered to sit down and count them all. Then along comes someone who says, you are running out of raw materials, so you are going to shut your business down soon. He shows you a report that only counts a small fraction of the raw materials avaliable. "You see that," he says. "You are runinng out of raw materials.

Such is the case with Uranium. No one knows how much Uranium there is, because no one has produced a truely systamatic account. There is however a whole lot.

James Hopf notes:

The “proven reserve” estimates are flawed for two primary reasons. First of all they do not consider the fact that very little effort, or money, has been put towards uranium exploration thus far. Second, they do not adequately account for the tiny effect that uranium ore price has on final nuclear power price, and the maximum allowable prices that they use to determine “economically recoverable” reserves are far too low.

The effort made thus far in uranium exploration is absolutely negligible compared to the many hundreds of billions (trillions?) of dollars that has been invested in oil and gas exploration, technology development, and extraction, etc… As the history of oil and gas shows, as these investments are made, more and more reserves are found. As discussed earlier, we stopped exploring for new uranium deposits relatively soon after we started looking, since we rapidly found “all we need”, due to sluggish nuclear expansion and the glut of uranium from decommissioned weapons. Now, even the majority of known sites and mines lay idle due to the low ore price (although this is starting to change).

As the price of uranium ore goes up, significant resources will go into uranium exploration, and many new deposits will be found, including many high-grade ore deposits that were simply never discovered. It is likely that the amount of uranium in yet-to-be-discovered high-grade (low cost) ore deposits greatly exceeds that which exists in currently-known high-grade deposits. In addition to these high-grade deposits, a large number of lower-grade deposits, both currently known and yet to be discovered, will become economical and will be developed. This is what happened with oil and gas, and it is even more clear that this is what will happen with uranium. Given that uranium produces about a million times as much energy as an equivalent mass of oil, gas, or coal, the amount of energy locked up in uranium (in the earth’s crust) exceeds that locked up in fossil fuels by several orders of magnitude. This bodes well concerning the amount of uranium that will/can be eventually discovered and developed.

Calculations of reserves make assumptions about prices and energy input in recovery that may not prove valid. It has been argued that Uranium reserves have not increased signikficantly for over a decade, yet in fact, uranium prices have been so low that little effort has been expended in the search for new Uranium supplies. Yuri Sokolov, a IAEA deputy director general, points to 4.7 million metric tons of "identified resources," which can be mined for less than $130 per kilo. But geological evidence and knowledge of uranium in phosphates, makes it very likely that more than 35 million metric tons can be economically mined.

One of the primary reasons why there is no market for breeder reactors, is that the uranium supply is so plentiful that many easily accessed potential uranium sources are ignored, simply because it would cost a few dollars more to extract uranium than current market pays for uranium. Some of these sources include:

* Coal fly ash - World uranium reserve several hundred thousand tons
* Phosphate mining tailings - an enormous reserve
* Sea water - Economically possible at $100 a pound - 4.5 billion tons reserve

In addition, there is a world wide stock of one million tons of depleted uranium, all of which can fuel into breeder reactors. This does not count the hundreds of thousands of tons of supposibly spent reactor fuel, mostly sitting idle at nuclear plants, where it is called unfortunately, nuclear waste.

And of course there has been no prospecting for uranium in over 30 years.

Deffeyes & MacGregor estimate that there are 40 trillian tons of Uranium in the earth's crust. Even with avaliable mining technology deposits with uranium concentrations as low as 10 - 20 ppm can be mined with an energy output gain of 16 - 32 times energy input. According to Deffeyes & MacGregor data, that would be over 80 billion tons of uranium.

Breeders reactors produces 100 times as much energy from each pound of natural uranium than old fassion Light Water Reacors do. Thus a 50 year uranium supply for light water reactors would last 5000 years, with breeder reactors. In addition to uranium, the world is well supplied with thorium. Thorium can be breed into fissionable U233. Thorium is 4 times as plantiful in the earth's crust as uranium.

Easily and inexpensively extractable uranium and thorium can sustain a high energy, world wide economy for tens of thousands of years.

The most significant issue then is the efficient use of uranium and thorium as reactor fuels. Right now, uranium is not used to anything like its greatest possible efficiency. Current reactor technology, is based primarily on the use of U235 to create chain reactions. U235 constitutes 0.7% of natural uranium. During the reactor fuel cycle, perhaps 0.3% of the original U238 is transformed by nuclear alchemistry into reactor grade plutonium and burned.

That means that the energy of 99% of all U238 is not tapped by current nuclear technology. How much of it can be tapped? The answer is all of it. Given technology we already posses, we have the potential to tap 100% of the energy in natural uranium. The reason why we don't do it, is that reactor manufactuers and power companies think it is cheaper to run new uranium through a reactor, than to extract the total energy from the uranium they have partially used.

Although the technology already exist to use abundant thorium as a reactor fuel, reactor manufacturers and public funding agencies have directed little effort to achieve its potential.

All this does not stop people from claiming we are running out of Uranium.

Update 2/13/08 (From a comment I made in Peak Oil today:

Uranium is 99.3% U238, and 0.7% U235. About 0.3% of the U238 gets transmutated into plutonium in LWRs and gets burned. The 0ther 99% of the U238 can be transmutated into PU239 in breeder reactors. That makes the energy efficiency of breeders 100x of that of LWRs. The price of heavy water in not nearly as expensive as you have indicate. The current cost of heavy water @ $300 per kilogram is far cheaper than Uranium enrichment. Thus heavy water use is cost effective in reactorsa, because it produces far superior burn rates for reactor fuel. In fact so called spent nuclear fuel, can be very inespensively burned in heavy water reactors.

The Canadians prefer heavy water CANDU power reactors and sell them all over the world. http://en.wikipedia.org/wiki/CANDU

Atomic Insights (Vol 2,#3) reports:

The heavy water in a CANDU requires a capital investment equal to approximately 20 percent of the cost of the plant. Overall, the initial capital cost of a CANDU is ten to twenty percent higher than a comparable light water reactor depending on local labor costs.

On a lifecycle basis, however, lower fuel costs tend to make the two systems roughly comparable on price, so decisions between the two are often made on the desire for independence, the availability of local labor, the availability of capital investment, the existing infrastructure of the customer, and the availability of vendor incentives.

However your account of breeder technology made serious omissions. Argonne National lab successfully operated the Experimental Breeder Reactor II (EBR-II) for 30 years. The primary reason why breeding technology is not in vogue is that Uranium is still so plentiful, and manufacturers and utilities still think it is cheaper to stick ever more new uranium and plutonium into reactors, rather than breed more. Civilian power reactors are currently burning up cold war era nuclear bombs and warheads. Getting rid of the nuks keeps fuel costs low. There are other breeder technologies which you failed to mention including the molten salt reactor, which breeds thorium. Thorium is 4 times as common as uranium in the earths crust.
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You scoff at the notion of extracting Uranium for sea water, yet the Japanese have already developed the technology to do it.
http://nextbigfuture.com/2007/11/two-proposals-for-mining-ocean-for-720....

A Japanese report to the ANS can be found here:
http://www.ans.org/pubs/journals/nt/va-144-2-274-278

More information can be found here:
And here:.

I stated in my previous post I noted that with energy input to recovery ratios possible with existing extraction technology, more that 80 Billion tons of uranium are recoverable. We can expect on this basis to obtain another 320 billion tons of thorium, enough to last the human race for a very long time.