On “immortal” nuclear power plants

On “immortal” nuclear power plants

Technology in Society 26 (2004) 447–453 www.elsevier.com/locate/techsoc On ‘‘immortal’’ nuclear power plants Alvin M. Weinberg  Oak Ridge Associated...

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Technology in Society 26 (2004) 447–453 www.elsevier.com/locate/techsoc

On ‘‘immortal’’ nuclear power plants Alvin M. Weinberg  Oak Ridge Associated Universities, P.O. Box 117, Oak Ridge, TN 37831-0117, USA

Abstract US nuclear reactors have demonstrated that they can continue to operate well beyond their thirty or forty year operating licenses which, at the time they were issued, were based on criteria for large fossil fuel power plants. Accordingly, a longevity criterion for 21st century reactors is proposed here, designed to last 100 years or more. Cheap electricity from a fully amortized long-life reactor is a gift from the generations that paid for the reactor to future generations that benefit from it, and they compensate (to a degree) for the burden of geologically sequestered wastes. # 2004 Elsevier Ltd. All rights reserved. Keywords: Nuclear reactors; Operating licenses; Energy systems; Depreciation; Energy costs; CO2 reduction

At the end of World War II, many of us who had worked at the Chicago Met Lab turned our attention to possible applications of fission energy. Our New Piles Committee examined many possible reactors and many possible applications. Serious effort focused on one application, submarine propulsion, whose design hardly involved economic consideration. High-pressure water as coolant and moderator was chosen for this application—not because it was cheap or particularly safe, but because such a reactor could fit into a cramped submarine. When Admiral Rickover’s Nautilus was moved to dry land at Shippingport, Pennsylvania, economic reality set in: nuclear kilowatt hours (kWh) were expensive, not cheap. I remember Karl Cohen, Chief Nuclear Scientist at GE, and the original proponent of slightly enriched, light water reactors (LWR), expressed his doubt that nuclear power would ever be economical—unless, at the very least, plants were much larger that the paltry 60 megawatts of energy (MWe) at 

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0160-791X/$ - see front matter # 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.techsoc.2004.01.025

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Shippingport. Karl warned that we were rushing the technology by building 500 MWe monsters before we had learned all the lessons of 60 MWe. A key to economical nuclear power has been the scaling law: Bigger is Cheaper. Indeed, Phil Hammond preached that if reactors were large enough, the unit cost per kWh would go down to, say 1¢/kWh, where nuclear electricity could be used to power heavy chemical processing. This was the era of mythical nuclear-powered agro-industrial complexes, and Sen. Howard Baker’s brave Senate resolution urging that ‘‘cheap’’ nuclear power based on huge LWRs could make the deserts of the Middle East bloom. Since the scaling laws were presumably based on sound engineering principles, I and others had accepted the doctrine of ‘‘Bigger is Cheaper.’’ As it turned out, large LWRs eventually did produce electricity that was competitive in the US and in France. Thus, despite the skepticism expressed by the nuclear community at my speech in 1977 at the 20th anniversary of the International Atomic Energy Agency (IAEA), in which I preached the doctrine of ‘‘Bigger is Cheaper,’’ as things have turned out, this doctrine has been verified. One purpose of this paper is to argue that just as ‘‘Bigger is Cheaper’’ was a key to producing competitive nuclear electricity, or to produce nuclear electricity cheap enough to desalt the sea, or to manufacture H2 from water, today we may have to invoke another design principle. So I propose that longevity be the design criterion for the 21st century. Reactors in the coming century should be designed to last 100 years or more. When I joined the Manhattan Project in 1941, I was 26 years old. My life expectancy was about 60-odd years. Today, I am near 88, and my life expectancy is around 90—in short, during these 60 years my personal life expectancy has increased about 30 years. To a remarkable degree, nuclear reactors also seem to be lasting longer than their design lifetime. First I will speculate on how long power reactors might last, and if they indeed turn out to be ‘‘immortal,’’ what this might imply for the future of fission power.

1. Are reactors outliving their design lifetime? The present generation of US reactors have 30- or 40-year operating licenses. Why 40 years? As near as I can fathom, because large fossil power plants of that period were unable to compete against more efficient plants after 40 years or so. But thermal efficiency in a nuclear plant affects the cost of generation much less than does efficiency in a fossil plant, so there was no intrinsic benchmark for setting the licensing time. Forty years was the projected lifetime of fossil plants—and essentially by default, that became the licensing period for nuclear plants as well. Now that the Nuclear Age is 60 years old, we are realizing that LWRs (like humans) are lasting longer than their design lifetime. To date, 14 LWRs have been re-licensed for another 20 years, 16 more are in process of being re-licensed, and Chairman Richard Meserve predicts that almost all US plants (approximately 100)

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will apply for renewal. Indeed, current proposed reactors are designed to last 50 to 60 years. 2. The economic advantage of long life In a sense, time annihilates capital costs. Total production cost in a nuclear power plant should radically diminish when the original debt is paid off. Maurizio Cumo, a proponent of the very long-lived, modified, pressurized water reactor (PWR) (the so-called MARS reactor), claims that after the debt service period is over, the price of electricity from MARS falls to less than 1.4 ¢/kWh depending on the load factor (see Fig. 1). During the debt service period, the cost of electricity is, of course, higher, around 5–6 ¢/kWh depending on the interest rate (see Fig. 2). The economic advantage of full amortization is, on the face of it, impossible to realize since cheap electricity is generated not today but, say, thirty years from now—but has to be paid for now. As we see the matter today, no utility executive will buy a reactor whose full cost advantage accrues only in the next generation. In a paper I wrote in 1985, ‘‘Immortal Energy Systems and Inter-Generational Justice,’’ I pointed out that cheap electricity from a fully amortized, long-lived reactor is a gift that the generation paying for the plant bestows on future generations. To a degree, this gift to future generations compensates for the burden of geologically sequestered wastes. Whether an equitable compensation scheme, which ‘‘pays’’ the price of geologic wastes with low-priced electricity from long-lived reactors, can be devised remains to be seen. 3. Is a 100-year reactor realistic? My most embarrassing experience in nuclear energy was the plenary talk I gave at the IAEA in 1977, on the 20th anniversary of the founding of IAEA. At the

Fig. 1. Average cost of kWh after the debt service period.

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Fig. 2. Average cost of kWh during debt service period versus debt service period duration (load factor, 85%).

time, I was enchanted by the scaling law: that total cost of a nuclear plant should scale as the 0.3 power of the unit size, and therefore the cost per unit of output would diminish as the 0.7 power of the size. I spoke therefore of nuclear power plants as large as 10,000 MW of heat, and cost per kWh of a few mills (in 1970 dollars). I predicted a nuclear ‘‘Eden’’ in which monstrous nuclear plants would supply electricity at a few mills/kWh. My euphoria was further increased by the loss leader at Oyster Creek and the claim by GE and Westinghouse of around $100/kw even in modestly sized LWRs—this at a time when reality was dawning and capital costs were escalating far more sharply that any scaling law could defeat. No wonder that after the routine applause at the break following my talk, the word ‘‘charlatan’’ was heard frequently. I must be brave indeed, 25 years after that infamous talk where I preached ‘‘very big was very cheap,’’ to claim that very long life might mean even cheaper nuclear power. But this time I am resting my case on experience: the re-licensing of many American reactors, and the expectation that essentially all 100+ LWR reactors will be re-licensed. What is the cost per kWh from re-licensed nuclear power plants? Even in this age of $2000/kW for a new plant, re-licensing costs are only tens of dollars per kW and the cost per additional kWh from a re-licensed reactor is correspondingly low. But suppose the new generation of LWRs last, say, 100 years without serious refurbishing costs. Then, as Cumo estimates, the cost per kWh might come to around 1 ¢/kWh.

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When we were enchanted by the illusion of very cheap nuclear power, we speculated on how the most basic heavy chemicals could be based on cheap electricity. We estimated how low the price of a kWh would have to fall for electrical processing to displace conventional processing. We claimed we could desalt the sea, produce H2 by electrolysis, or ammonia, if only electricity were cheap enough. My message in 2003 is therefore simple: just as size and then inherent safety become a design criterion for the present generation of reactors, so I believe longevity should be a design criterion for the coming generation of LWRs. I am suggesting that we develop reactors that will last 100 years or longer, and that we invent economic and technological practices that allow us to exploit the cost advantages of reactors that have outlived their original licensing periods. In particular, any new reactor ought to be designed ab initio for easy, and therefore cheap, replacement of all parts.

4. Carbon dioxide and nuclear reactors When I first began my work in the 1940s, the underlying reason for developing nuclear reactors was a perceived ultimate shortage of energy. But in the past ten years or so, an important—if not the important—incentive for nuclear is now CO2 abatement. Since the original aim—electricity at a competitive cost—has been achieved, we have now made CO2 abatement a primary aim. Whether or not one accepts the Kyoto Protocol, all can concede that the increase in atmospheric CO2 of approximately one ppm/yr, or about 3 GTC/yr (gigatons of carbon), must be dealt with. Alfred Perry has asked the question: how much CO2 can be saved if energy is derived from uranium instead of from fossil fuel? Perry calculates that 5.5 GTC can be saved per 106 tons of uranium burned in power reactors that use 0.5% of the uranium fuel. This is the efficiency of fuel use in today’s LWRs. The atmosphere contains 770 GTC and man injects roughly 6 GTC/yr, of which about 3 GTC remains in the atmosphere. The amount of uranium in the reserve available at $100/kg is estimated to be 20  106 tons of uranium. Thus, even if all the reserve was burned in today’s LWRs, the amount of carbon saved would be only about 110 GTC compared to the 770 GTC already in the atmosphere. Thus nuclear energy helps the CO2 problem but only if more uranium is discovered, or if the efficiency of use is, say, 70%, not 0.5%. Moreover, as many as 5000 reactors would be needed to really control the CO2 in the atmosphere by using uranium rather than fossil fuel. The strategy for using CO2 as the primary incentive for nuclear power seems to hang either on finding more uranium (possibly from seawater) or developing a breeder that burns uranium with 70% efficiency, as well as the acceptability of a large fleet of reactors. Ever since Szilard, Wigner, and Fermi invented the breeder, this has been the basic strategic decision: can we extract the 2  109 tons of uranium from seawater economically, or can we develop a 70% efficient breeder? The breeder has been demonstrated (and EBR-II showed no signs of wear even

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after 30-odd years of operation). Has economical uranium from seawater been demonstrated? This is still an open issue.1 5. Possible show stoppers: Fermi’s warning At a meeting of the New Piles Committee in 1944, Fermi voiced his reservations about nuclear power. This warning, uttered 58 years ago, has reverberated in my mind ever since Fermi voiced it. How have we responded to Fermi’s warning? We have developed a miraculous new source of energy, but it is encumbered with vast radioactivity and the threat of proliferation. Will the public accept an energy source so encumbered? This topic is far too large to cover in this venue, and I can only state briefly my thoughts about making nuclear energy acceptable to the public. When I spent 1974 in Washington, I realized that in a certain sense, a nuclear power plant preempts the land on which it stands. Therefore new reactors will have to be built on sites already occupied by old reactors. Cal Burwell, Jack Ohanian, and I argued that 80 existing sites in the US could be expanded. In short, ‘‘nuclear parks’’ have a certain logic, and I predict they will likely become the norm—indeed, probably immortal—at least in the US.

6. Nonproliferation? As for non-proliferation, we are holding our collective breath as we watch the Iraq situation. Is preemptive war the only way to live in a world populated by several thousand nuclear reactors? Dr. H. Feiveson views a large fleet of reactors as so prone to proliferation that he advises rejection of nuclear power. I cannot believe that US ingenuity is unequal to the task of controlling nuclear energy, even a worldwide fleet of several thousand reactors located at several hundred heavily guarded nuclear plants under international control. Indeed, this may amount to returning to the Lilienthal/Acheson proposal of the 1940s.2 Perhaps as mutual assured destruction lapses into irrelevance in the age of America’s superiority, we shall accept more stringent and intrusive ways of controlling fissile material. Does such international control of fissile material imply a weakening of national sovereignty? Some 10 years ago, Secretary of State George Shultz suggested that 1

If the primary incentive for building new nuclear plants is carbon abatement, Larry Foulke, President of the American Nuclear Society, argues that just as TVA paid for its dams to control floods, then the government must finance reactors built for an analogous social purpose— CO2 abatement. 2 David Lilienthal and former Secretary of State Dean Acheson wrote a report, published on March 28, 1946, which suggested that international control of atomic energy might work ‘‘if the element of rivalry between nations were removed.’’ This could be done, the document proposed, by assigning ‘‘the intrinsically dangerous phases of the development of atomic energy to an international organization responsible to all peoples.’’ This authority would have a monopoly on uranium; it would license the use of ‘‘denatured’’ plutonium, which is difficult to convert into an explosive; and it would spread its mines and factories around the world so that the benefits they brought would be dispersed.

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development of accurate missiles may presage just such a world. The price of using nuclear energy to control carbon may be a loss of national sovereignty. In a way, what is happening in Iraq is an example: Iraq’s national sovereignty is being challenged in a preemptive war. Let me close on a somewhat different note. As I see the 21st century unfolding in terrible directions, I ask myself two questions: . Were early pioneers right to invent nuclear weapons? This is a no-brainer—we had no choice, given our knowledge of Hitler’s bomb project. . Will the coming generation be up to the task of living safely with thousands of reactors? I shall not be here to see the answer. I can only wish the coming generation as much luck as my generation had in avoiding nuclear war in the second half of the 20th century.

Acknowledgements I am grateful to Charles Forsberg, Gregg Marland, Alfred Perry, and Richard Weinberg for suggesting improvements in this manuscript. Alvin Weinberg received his BS, MS and PhD degrees in Physics at the University of Chicago. In 1941 he joined the original group that developed the first chain reactors at the University of Chicago. He has since been a leading figure in the development of nuclear energy. Among his accomplishments was the proposal to use pressurized water reactors for submarines. He served as Research Director and then Director of the Oak Ridge National Laboratory from 1948 to 1973; Director in 1974 of the Office of Energy Research & Development in the Federal Energy Administration; from 1975 to 1985 as Director of the Institute for Energy Analysis of the Oak Ridge Associated Universities, where he is now a Distinguished Fellow. He is a member of the National Academy of Sciences, the National Academy of Engineering, the American Academy of Arts & Sciences, the American Philosophical Society, and a Foreign Member of the Royal Netherlands Academy of Sciences. He collaborated with Eugene Wigner on the standard book on nuclear reactor theory, The Physical Theory of Neutron Chain Reactors, and he has been a prolific writer on the interactions between modern technology and society, coining phrases that have become part of our everyday language, such as ‘‘big science,’’ ‘‘technological fix,’’ and ‘‘Faustian bargain.’’