Sunday, June 20, 2010

Toward a White Paper on a Mass Global Deployment of Nuclear Power: Safety

Nuclear energy poses the well known risk of proliferation and of catastrophic accidents of the scale of Chernobyl whose consequences would last far into the future, afflicting generations who will not have experienced the benefit of the energy. Hence four criteria must be considered in proceeding to a low or zero-CO2 future:

• Cost
• The speed with which the transition can be made (since the climate change problem is now widely recognized to be urgent)
• Potential new severe burdens or risks on future generations not deriving from CO2 emissions
• The problems of security associated with a re-organized energy system. - Annie and Arjun Makhijan
In this statement, the Makhijanis set out in digest form the substance of the anti-nuclear argument. It is the purpose of this White Paper to set out arguments that contradict the four Makhijani anti-nuclear contentions, and to argue that a speedy and relatively low cost mass global deployment of nuclear power generating facilities is possible without "Severely burdens or risks on future generations," and while lowering rather than increasing security problems associated with nuclear weapons.

The Makhijanis presented their list in an essay titled, "Low-Carbon Diet without Nukes in France." This essay was intended to demonstrate that France could transition to a post-carbon and post-nuclear energy system, without paying an unacceptable cost. There are several reasons why the Makhijani transition would in all likelihood be a failure. First it relies to a very large extent on energy efficiency, without enquiring into the potential obstacles the transition to a high efficiency energy system would face, and without any attempt to assess the cost of of that transition. For example, the Makhijanis' favor heating with ground source heat pumps, but they also favor co-generation. This is an either/or choice, however. Ground source heat pumps while energy efficient entail high capital and repair costs, making their widespread adoption by home owners unlikely. One of the more astonishing aspects of the Makhijanis' post-nuclear, post carbon-plan, is the extent to which it is not really post carbon. Rather that simply eliminating the use of carbon based fuels, the Makhijanis would attempt to use them more efficiently. Most Danish power plants are either wind turbines or co-generation facilities, and Denmark has a much higher per-capata carbon emission rate than France. Thus, the assumption that co-generation can be substituted for nuclear power, without carbon penalties is questionable at best.

The cost to French electrical consumers under the Makhijani system is also open to question. The environmentally correct electricity in Denmark is over twice as expensive as the nuclear generated electricity is in France. Danish electricity is the most expensive in Europe, and the effect on the French economy of high priced energy would require further investigation.

If the cost of French electricity does not rise in the Makhijani system, then we have to ask if the consequence of greater efficiency would not be a rebound in electrical demand, or even an overall demand growth. Amory Lovins has suggested that efficiency would curb consumer demand for electricity, but this Lovins idea has meet with withering criticisms by Robert Bryce and David Bradish as well as many other critics. Critics argue that Lovins' appeal to energy efficiency is confounded by Jevons Paradox, a well established economic principle that sates that on a macroeconomic level, energy efficiency triggers a rise rather than a decline in energy use. In addition on a microeconomic level, economist have observed a rebound in energy use following the adoption of an energy efficient technology. Despite statements that he would answer Bryce and Bradish's criticisms two years ago, Lovins has never done so. Thus, at the very least the Makhijanis need to demonstrate that the critics of Lovins overestimates of the benefits of energy efficiency would not also make a valid case against his claims about the benefits of energy efficiency for French society.

It should be noted then that in a plan which calls for filling the gaps in efficiency and renewable energy generation by the use of fossil fueled generating facilities, any short falls would have to be filled with carbon-emitting energy sources. Thus to the extent the Makhijani plan proves defective in practice, it will produce rather than eliminate unacceptable levels of CO2 emissions. Similar problems would effect non-nuclear carbon mitigation schemes proposed by Amory Lovins.

Amory Lovins claims:
The nuclear industry is eager that the public does not understand this argument . . . Amory Lovins
But what does Amory Lovins mean by the term "the Nuclear Industry?"

There is no such thing as "The Nuclear Industry". There are several businesses that produce reactor designs, and in some cases, build reactors. There are parts suppliers, and construction companies, many of which build many other things besides reactors. There are uranium mines, uranium enrichment facilities, and fuel fabricators. There are reactor owners. But arguably in many cases business that do these things, do many other things as well. Reactor manufacturers may also manufacture wind generators, steam generators for coal fired power plants, and natural gas fired gas turbines. Uranium miners may also mine other materials at the same mine, and may operate mines from which no uranium is produce. Uranium enrichment facilities may be own by national governments. Power reactors may be owned by agencies of national governments. Thus the term "the nuclear Industry" reifies complex, and diverse realities.

In so far as nuclear energy must play an important role in sustaining modern, materials oriented civilization, the challenges which confront nuclear power, are challenges which confront human society. There are those who question the value of the continued existence of a high energy, wealthy civilization. I am not one. I will only say, that there are moral penalties for not sustaining a high energy, wealthy civilization, and for not making the benefits of that civilization inclusive to all of the people on earth, and I find the moral costs unacceptable. In addition, I would argue that the means exist by which, if we choose to use them, a civilization with access to high levels of energy can be sustained on earth for millions of years. The challenges which confront nuclear power then, are the challenges which must be meet, if a high energy, wealthy civilization, encompassing all the people on earth, is to be created and sustained.

The challenges confronting nuclear power are:
* assured nuclear safety
* An assured nuclear fuel supply throuh the efficient use of nuclear fuel
* the recycling of fission products into industrial use
* making energy produced through nuclear power available at a low cost
* developing the technology that will makes meeting the first four goals possible
* Achieving the first five goals rapidly, and deploying the technology world wide as quickly as possible
* Severing potential links between massive use of civilian power reactors and the spread of nuclear weapons.

Assured Nuclear Safety

Ralph Nader tells claims that in 1964 he attended a conference at the Oak Ridge National Laboratory. Over lunch Nader claims that he began asking nuclear engineers some questions. "They couldn't answer them, or the answers weren't satisfactory," Nader claims. "'What could happen if a system goes wrong?' Nader asked. They avoided any such descriptions or said, 'we've got defense in depth' -- and other jargon." "Defense in Depth" was the name of a very successful but expensive approach to nuclear safety that was proven to be effective when, at Three Mile Island, safety systems designed to implement the "defense in depth" safety philosophy prevented a single human casualty. By describing a discussion of things things that he did not understand as jargon, Nader revealed his lack of willingness to understand nuclear safety. As Gomer Pile use to say, "surprise, surprise surprise."

There were of course, other people at ORNL who could have the answered Nader's 1964 questions, had he been willing to listen. If Ralph Nader wanted to talk to people who could answer his questions about what could go wrong in reactors and under what conditions, he could have talked tp George Parker, or he could have talked to my father. Needless to say, Nader did not seek out nuclear safety experts to answers to his questions. Certainly Alvin Weinberg, who was a friend to Ralph Nader's sister, Clair, would and could have answered Nader's questions about nuclear safety, and would have made himself available to Ralph if Claire had indicated to Weinberg that Ralph wanted information on nuclear safety. It is quite possible that Nader talked to someone in Oak Ridge who did not answer his question, but English, but Narder was not interested in what he had to say. alternatively Nader's informant, that day gave him lucid information in plain and simple information, Had Nader sought out answers to his nuclear safety questions in 1964, he would have found them, but Nader wanted answers that made nuclear scientist look bad, not reliable and accurate information.

There is logic, which is the science of right reasoning, and then there is green logic, which makes relies on crazy arguments about energy. According to green logic, if energy source A kills thousands of people, it is safe, but if energy source B has kills only a handful of people during its history, it is too dangerous to use. Furthermore, according to green logic, energy source B should be shut down because it is too dangerous, and replaced by safe energy source A.

Energy source A is the use of natural gas as an energy source, which Source B, is nuclear reactor generated power. Comparative Assessment of Natural Gas Accident Risks, is a study of risks related to natural gas use by Paul Scherrer Institute. The study authors consulted no less than 23 comprehensive accident databases, most world wide. Major accidents identified in these data bases and identified from several other sources, were aggregated into a single database that included 18,400 accidents.
A total of 6404 energy-related accidents correspond to 34.8% of all accidents or 49.5% of man-made accidents. Among the energy-related accidents 3117 (48.7%) are severe, of which 2078 have 5 or more fatalities.
The data base recorded over 100,000 energy related casualties in all energy sectors excluding nuclear, and 31 energy related casualties in the nuclear sector. Of the non-nuclear casualties, 2043 were due to natural gas related accidents. An objective observer from another planet might conclude that of all energy sources listed in the study, that people who valued risk avoidance would chose nuclear power. Yet Greenpeace, green energy maven Amory Lovins, and Green advocate Joe Romm all call for the replacement of nuclear with natural gas fired energy sources. Greens site the alleged danger of nuclear power as a principle reason for the switch from nuclear to natural gas.

Nuclear power technology is by far the safest of energy technologies. Based on experience, based on actuarial evidence, fatality risks for nuclear power plants in OECD nations is far lower than for fossil fuels. According to the report "Sustainability of Electricity Supply Technologies under German Conditions: A Comparative Evaluation published by the Paul Scherrer Institute
representative PSA-based results obtained for nuclear power plants in Switzerland and in USA show latent fatality rates typically of the order of 0.01 per GWe year. The corresponding immediate fatality rates are practically negligible.
Even the latent PSI risk estimates are controversial because they are based on assumptions for which inconsistent data sets are available. The latent casualties from nuclear plant operation is predicted on the basis of he so called linear no-threshold hypothesis (LNT) which suggests that adverse health effects can occur the LNT hypothesis predicts that variations in background radiation levels would effect human health. But assessments of the health of people who live in high background radiation areas fail to support the conclusion. Health Physicist Bernand Cohen, found evidence that increasing levels of background radiation from naturally occuring radon, were associated with decreasing cancer rates. Thus the LNT hypothesis appears to have been falsified, Yet it remains politically correct. Even if we assume. If the LNT hypothesis is not assumed, the fatality rate from the operation of nuclear plants in OECD countries drops to 0.0.

Despite powerful evidence of the safety of the previous generation of nuclear technology. reactor manufactures have continued to develop even safer reactor designs. The probability of a casualty producing nuclear accident occurring with Generation III+ reactors approaches once during the life of the universe. To expect greater safety, is to take an excursion into the realm of the absurd. The high levels of nuclear safety achieved by current reactor designs, comes at a high cost. Extremely safe Light Water Reactors are expensive to build. The challenge for future nuclear safety developments is to continue providing the current high level of nuclear safety, while dramatically lowering nuclear construction costs.

Nuclear safety operates at many levels. Reactor safety is the primary level of nuclear safety, and the defenses against accidents in a reactor may feature both redundancy and a many leveled safety defense system. The current generation of Light Water Reactors have high levels of safety built in to their designs. Nuclear safety engineers have calculated that the General Electric Evolutionary Simple Boiling Water Reactir is so safe, that it would experience a core meltdown once every 29 million years. In contrast the Yellowstone Super volcano, which is capable of killing milllons of people with an erruption, erupts every 600,000 to 800,000 years. It has been 640,000 years since the last erruption of the Yellowstone super volcano. Thus the likelihood of a major reactor accident and its consequnces, ought to be placed in the context of far more likely natural disasters.

Steps that can be taken to prevent reactor accidents include:

A. good design based on an up to date understanding of reactor safety,
B. An exhaustive follow through of all safety related reactor features in the procurement of manufactureing materials and replace ment oarts, The actual manufacture and maintence of the reactor, and reactor operations
C. systematic faults detected in procurement, manufacture and operationals, with a prompt and complete follow up.
D. Redundant or fall back systems in the event of the failure of a reactor system.
E. Automatic system response that rely ion the laws of nature, rarher thn opeartor intervention.
F. Reactor siting consistent with reactor safety issues. Experimental reactors placed in remote locations.
G. Reactor staff should be both well trained and highly motivated to follow all safety guidelines.

The second level of nuclear safety is accident mitigation. These would include those elements of reactor design that would tend to diminish the effects of a nuclear accident on the public. Mitigation would include both internal reactor design features, and design features of the reactor facility that would tend to mitigate the effects of a major nuclear accident. Mitigation defenses can be in depth. Hence in the event of a core meltdown in a light water reactor, the reactor pressure vessal would pose a significant defense against the escape of solid fission products. The reactor containment dome would form another layer of defense against fission product release, while the isolation of the reactor would lead to the dissipation of radioactive gases, and the precipitation of solid radioactive particles escaping the reactor containment facility prior to contacts with human communities.

Accident mitigation would include, the automatic shutdown of a reactor after a partial system failure, the automatic initiation of back up cooling and/or emergency cooling in the event of a primary cooling syetem failure. The design of reactor monitoring panels and system alerts to give clear and concise information about what is happening, without creating an overwelming flow of information. Staff training in accident management. Well defined accident response procedures to be included in staff training. The management of initial recovery after accident related shut down, Well defined accident cleanup and recovery procedures.

A third level of defense would be the management of public consequences after a nuclear accident. These wouldinclude the notification of the NRC, as well as Federal, State and Local officials. Steps which might be taken to manage the consequences of a serious accident include evacuations, bans on the use of potentually contaminated food and.or water. Provisions for safe sheltering of at risk populations, andthe distribution of KI pills, as well as other pre-planed interventions by the federal, state and local governments.

Normal accounts of nuclear safety defense in depth stop at this point. There are however other levels of nuclear safety, A forth level would be a well informed public. Nuclear safety is a genuine matter for public concern. The public should demand the safest nuclear technology possible, and both support nuclear safety research and for monitoring of observance of safety rules and procedures by demanding that reactor operators comply with them, and that the NRC vigorously enforce them.

One of the great flaws of the anti-nuclear movement has been to disimpower the public on nuclear safety issues. Figures like Ralph Nader, failed to avail themselves of opportunities to learn more about nuclear safety. Had Ralph Nader really wanted to understand the safety concerns that Alvin Weinberg discussed with Claire Nader and with Ralph himself, had Ralph Nader tried to understand what the ORNL nuclear safety engineer was telling him about defense in depth, the history of the first nuclear era might have ended differently. Had there have been a public outcry for nuclear safety in the 1970's rather than an anti-nuclear movement, the owners of the Three Mile Island reactor, would not havebeen allowed to get away with the safety errors they committed. Had there been a public outcry for safety research, staff safety training, and safe design of reactor control panels, there would have been no Three Mile Island accident. By convincing the public of the ill intentions of safety advocates within the nuclear community, and by convincing the public that nuclear safety was impossible, and therefore it had no stake in the development of nuclear safety improvements, the anti nuclear movement, disempowered the public on nuclear safety issues. It is up to the public to take its power back from the anti-nuclear movement, and assert its right to demand the highest levels of nuclear safety possible. Such a public demand would be a fourth level of nuclear safety defense.

The fifth level of of nuclear safety defense is nuclear safety research, and safe reactor design coupled with the actual replacement with reactors designed to current safety standards by reactors designed with even higher levels of safety. Nuclear safety is something that happens in time. Nuclear safety has a history. It has evolved during its history, and can be expected to continue to do so. It is perhaps unfortunate that the Light Water Reactior emerged early on as the predominant power reactor type. Light Water Reactors have inherent safety flaws. Those flaws can be largely worked around, by engineering reactor modifications, but those modifications are expensive. To much of the history of nuclear safety has been the history of increasingly expensive safety developments for the light water reactor.

Reactor scientist have known since the 1940's that it is possible to eliminate the very possibility of the most serious of reactor accident, the core melt down. Reactors designs developed over 50 years ago posses inherent safety feature that far surpass those of light water reactors. Furthermore one of those two advanced reactor designs, the Liquid Flouride Thorium Reactor,relies on an abundant nuclear fuel, Thorium, which it uses so efficiently that it will provide sustainable nuclear power for millions of years to come. Because of its efficient use of the Thorium fuel cycle, the LFTR also virtually eleminates the long term nuclear waste. Developing and implementing the LFTR reactor designs would not be inordinately expensive, or require an extensive period of time. The development cost for either reactor design would cost less than the cost of two light water reactors, or less than the cost of the imported oil the United States consumes in one week. The manufacturing cost for the LFTR would also be lower that the current cost of building Light Water Reactors. Thus at a relatively small cost the United States could acquire a fifth level of nuclear defense, one which would make the most serious reactor accident impossible, and solve other problems related to the use of nuclear energy in the generation of electrical power.

Nuclear researcher Ralph Moir and famed nuclear physicist Edward Teller reviewed the safety features of Molten Salt Reactor technology. They concluded that Molten Salt Reactors had outstanding safety characteristic. Some time ago I wrote an essay on LFTR/Molten Salt Reactor safety from the prospective of a system of barriers to radiation release. My agenda was to argue that LFTR safety could be achieved through a system of barriers to the release of radioactive materials. This argument assumed that a fuel spill was the over riding safety issue. However, the classic texts on MSR safety (Gat and Dodds) do not examine MSR safety primarily in terms of a system of barriers. Gat and Dodds believed that
The Ultimate Safe Reactor (USR) is a special concept of a molten-salt reactor with prime and complete emphasis on safety. The USR uses a processing frequency, yet to be developed, that is about an order of magnitude higher from that contemplated for the molten salt breeder reactor (MSBR). The MSBR had a ten-day inventory turn around in the fuel processing. The USR uses a one day or less of turnaround of the fuel inventory. This rather fast turnaround reduces the build up of all fission products with half-lives of a few days or longer. The reactor is an epithermal spectrum reactor and uses no moderator per se in the core. The clean core consists solely of a low-pressure vessel. Freeze valves are used throughout. The prime circulating pump is sized to assure no critical cold slug accident can occur. Furthermore, the USR uses the Th-U fuel cycle with a breeding ratio of exactly one. Thus, the USR has all the safety benefits that are passive, inherent and non-tamperable and, in addition, has proliferation-resistant attributes and simplified waste that is free of fissile material, which can be transported in any arbitrary size or quantity from the processing part of the plant.
Beyond the ultimate safe reactor Gat and Dodd argued that there could be an absolute and ultimate safe reactor:
The absolute and ultimate safe reactor (A+USR) is a special concept of the USR which utilizes natural convection to transfer the heat from the core to the heat exchanger. The A+USR has no safety-related mechanical operating parts nor any externally-actuated controls, it becomes the ultimate in PINT-safety. The reactor responds internally and inherently to a change in power demand via its temperature response.
Frequent processing of the fuel increases the fuel inventory in the processing part and puts high demand on the performance of the processing units. The removal of the fission products from the fuel stream occurs at low concentrations, which requires precision and sophistication. In an actual plant, an optimization between performance, inventory and safety is needed.Thus Gat and Dodd saw MSR (and LFTR) safety in terms of reactor design features, that prevented accidents from happening, and prevented bad things from happening in the rare event of an accident. Gar and Dodds, argue, in effect that absolute and ultimate safety can be manufactured into Molten Salt Reactors, and can be implemented through low cost mass production manufacturing methods.

As a consequence of the Gat and Dodds argument is that an elaborate and costly system of barriers is not required. to assure absolute and ultimate nuclear safety. Mass produced, factory manufactured features can in most cases be low priced. Thus from the Gat and Dodds perspective LFTRs can be more safe at trivial costs than LWRs can be with the massive expenditure of money on safety features. This leads us to consider drastic, cost lowering changes in the way reactors are built.

Even the worst sort of reactor disaster, say an aircraft attack on a reactor, would not cause a massive release of radioisotopes, because the nuclear fuel would be continuously cleaned of radioisotopes. Since an attack on a reactor no longer poses great danger for a civilian population, the reactor holds little value as a target for terrorist. Furthermore, Moir and Teller suggest the underground siting of Molten Salt Reactors. This underground reactor could not be damaged by aircraft attacks or even massive truck bombs.

It would appear then if Molten Salt Reactors could be brought to market, there would appear to be little doubt about its safety. The Molten Salt Reactor is capable of producing power at a safety level that will satisfy any rational person.

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