Long-term nuclear options They all pose threats to the environment. The degree of hazard, however, is substantially different for each
Kerry O’Banion Lawrence Livermore Nutional Laboratory Livermore. Culil: 94550 With its fiscal year 1982 budget, the Reagan administration has hegun to reorient energy research and development in the US. toward a nuclear future. While the Department of Energy’s (DOE) research and development funds for coal, solar, and conservation were cut 50%. 60%. and 65%. respectively, the funds for fission breeders and magnetic fusion increased 15% and 20%. Although federal money for energy-related environmental research may be reduced to a low level for at least the next four years, it appears that substantial funds will he appropriated for nuclear technology. Moreover, since it is now DOE policy to limit its own R&D role to long-term ventures, while leaving to industry the task of developing and commercializing near-term technology, fusion and breeder fission are expected to capture the hulk of funds in the nuclear category. The purpose of this article is to give a brief overview of how fusion and fission breeder reactors work, and the environmental consequences they pose. Although both technologies are in developmental stages, and the commercial versions of both may differ in many respects from today’s prototypes, we can at least identify their potential Fe01are n r r i c l n i n
ES&T how by-linrr. rep-
nww1 rhr r i r w of !he ourhorr. ond om edited hy ]he Wurhinlrlon .sla/f Ifyou are inliwrrled in umrriht,riug on o r ~ i c l econrocr Ihc monuying rdiror. 1130
Environmental Science 8 Technology
1 A structural crane with afuel-handling device loadsfuel into a nuclear reactor core operated by TVA
problems and make some order-ofmagnitude comparisons based on the intrinsic features of each that are visible today.
How do fusion reactors work? The primary fuel for nuclear fusion is deuterium, an isotope of hydrogen; its nucleus is composed of one proton (positive charge) and one neutron (no charge). In a fusion reactor, deuterium is made to combine, or Fuse, with tritium, another isotope of hydrogen (one proton and two neutrons), in order to form helium (two protons and two neutrons). In the reaction, kinetic energy is imparted to the extra neutron,
which zips away until it strikes the “blanket” of lithium that surrounds the reactor core, at which point it gives up its kinetic energy as heat. As in other types of reactors, the heat is then utilized to drive a conventional steam turbine to generate electricity. However, in order for deuterium and tritium to fuse, they must first be heated to extreme temperatures. The steps to obtaining power from nuclear fusion, then, are: heating the fuel to a temperature in the range of IO8 K, confining the fuel for a long enough time so the number of fusion reactions taking place produces more energy than is consumed in heating the fuel, and converting the energy to a usable form. At lo8 K, the fuel exists as an ionized plasma. The major problem with nuclear fusion is that no material container can be used for the fuel, since contact of the fuel and the container surface would instantly cool it helow the fusion temperature. Magnetic-confinement reactors (MCRs) are based on the fact that plasmas are conductive media and can be shaped by electromagnetic forces. In an MCR, the fuel is contained and insulated from the blanket surface by a strong magnetic field; creating and sustaining such a field, of course, requires substantial amounts of input energy (Figure 1). Of the two approaches to fusion energy now being pursued, magnetic confinement is the clear leader over inertial confinement, and thus discussion of fusion in this article is limited to the former. Nuclear Fusion is not inexhaustible in absolute terms, since it does consume nonrenewable resources as fuel. However, these resources are so large,
0013-936X/81/0915-1130$01.25/0
@
1981 American Chemical Societv
FIGURE 1
sdwrmaic of a fuslon power plant showing liquid llthlum as blanket medlum and primary coolant
Heat exchang,
A Generator Turbine
-__I__
Cooling water
Condenser
Fuel injector
and the amounts required so miniscule in comparison, that fusion may be considered inexhaustible on any time scale of human relevance. Deuterium exists in all waters at about 150 ppm. Tritium exists in nature only in trace amounts, hut it is “bred” within the reactor blanket. When struck by the neutrons produced in fusion reactions, the lithium in the blanket fissions to yield tritium and helium; the tritium is recycled into the core. The lithium required for MCR blankets is the resource most limited in availability; yet the U S . land-based resources alone would provide over 1000 years of energy at the present world consumption rate. The estimated quantity in the Oceans is -lo5 times this figure. Deuterium in Ocean water is about 200 times as abundant as lithium, and cheaper to extract (I). Despite the advances made in the past few years, the feasibility of a contained fusion reaction yielding a net output of energy remains to be demonstrated. Such a “break-even’’ reaction is expected to be achieved by the Tokamak test reactor due to be completed at Princeton in 1982. Beyond this milestone, a host of formidable problems in design and materials will remain to be resolved, but, based in part on the conclusions of D O E S Fusion Review Panel of prominent scientists, Congress last September enacted and President Carter signed an act establishing as a national goal the
completion of a demonstration MCR by the year 2000.
How do fission breeders work? In contrast to the MCR, the technological feasibility of the fast breeder reactor (FBR) is proven, and several nations other than the U S . have programs well underway. Last year, the Soviets began operation of a 600-MWe breeder, the USSR‘s fourth. Prototypes exist or are underway in the U.K., France, West Germany, and Japan, and the first commercial-scale device, the 1200-MWe SUPERPHENIX, is scheduled to be completed in France in 1983. All nuclear plants now in existence produce energy byfission. It is possible to split very heavy atomic nuclei, such as uranium, by bombarding them with free neutrons. When the nucleus is hit by a neutron, it splits into two major “fission products,” clumps of protons and neutrons in any of myriad pair combinations, plus two or three free neutrons. The kinetic energy imparted to the fission products is captured as heat, which is then utilized to drive a conventional steam turbine. A reactor is designed so that, on the average, one of the free neutrons goes on to split another nucleus; a stable chain reaction is thus set in motion, and the reactor hums along. Present-day reactors are fueled by uranium, which in its natural form consists of 0.7% of the isotope 235U and
99.3% 238U.While 23sU can be split very easily, 238U can only be split by neutrons above a certain range of kinetic energy (>1 MeV). Unfortunately, the free neutrons produced in fission reactions drop below this range very rapidly, into a second, lower range in which neutrons striking 238Unuclei tend to be absorbed or “captured,” dousing the chain reaction. To get around this problem, the cores of present-day reactors are submerged in water. The water acts as a “moderator,” slowing the neutrons down to an even lower kinetic energy .range, at which they can no longer becaptured. The water also acts as the heat transfer fluid; it absorbs the heat produced in the fission reactions and is then run through a heat exchanger to drive the turbine. Because reactors in the U S . use ordinary water as the moderator-instead of carbon, deuterium (“heavy water”), or some other material-they are known as “light water” reactors (LWRs). In order to be usable as LWR fuel, natural uranium must be “enriched” to a 235U content of 3-4%, heavy water reactors (the Canadian CANDU model), on the other hand, can be run on natural uranium. The alternative to the use of a moderator to slow the neutrons is to increase the percentage of more easily s lit, or “fissile,” nuclei in the fuel. 5U IS one such fissile isotope; 233U and the plutonium isotope 239Puare
P ‘
Volume 15, Number 10, October 1981 1131
the others. The FBR is based on this second concept (Figure 2). It utilizes a fuel composed of z39Pu and 238U, placed inside a blanket of 238U.Fission of the 239Pusustains the chain reaction, and the excess neutrons leak ogt to the blanket where;as in an LWR, they are captured by the 238U. When 238Ucaptures a neutron it becomes 239U,but this isotope decays in about two days to the fissile isotope 239Pu;thus, fuel is created as well as destroyed in both LWRs and FBRs. However, the ratio of 239Pucreated to 235Udestroyed is only about 0.6 in an LWR. FBRs, on the other hand, can be designed to create (in theory) up to 1.4 times the amount of 239Pu they destroy. Once provided with an initial amount of 239Pu, FBRs would from then on roduce all they required, and more. 23 U would have to be provided on a continuous basis, but the FBRs utilization of uranium is so efficient (60 or more times as efficient as an LWR) that its supply may be considered inexhaustible in human terms. U S . land-based resources would provide almost 3000 years of energy at the present world rate of consumption, and the oceans are estimated to contain
!
-300 times this amount ( I ) . year and be completed as early as Because the FBR requires fast 1989. neutrons, water must be replaced by some other heat transfer fluid, or Inherent problems of nuclear energy coolant, which does not slow them All forms of nuclear energy down. All FBRs under development (LWRs, FBRs, and MCRs) entail today use liquid sodium as the coolant. large inventories of radioisotopes and At regular intervals, the core and thus subject citizens in the reactor viblanket fuel elements in an FBR must cinity to both low-level “routine” rebe removed and reprocessed-as the leases and the risk of far larger reinventory of fission products and 239Pu leases due to mishaps; all produce rain the blanket builds up and as the dioactive waste that must be isolated 239Puin the core and the 238Uin the from the biosphere for long periods of blanket are depleted. The plutonium time; and all utilize information and and.uranium are separated and recy- materials that can also be used to cled into new fuel. The fission products fabricate nuclear weapons. But FBRs comprise the radioactive waste and and MCRs are quantitatively different must be isolated from the biosphere for from one another in all these respects, thousands of years. and bofh are substantially different The next step in the development of from LWRs. FBRs in the U S . is to begin conRadioactive inventories. MCRs have struction of the long-delayed 375 MW, two sources of radioisotopes-the triClinch River demonstration reactor at tium used as fuel and the neutrons Oak Ridge, Tenn. While former produced by the MCRs, which create President Carter prevented construca wide variety of radioisotopes by action for four years by halting licensing tivation of the blanket and other maof the project, Congress continued to terials near the reactor core. Tritium fund design work and the purchase of is both consumed and produced in a reactor parts. With no new technoclosed cycle within the reactor. Once logical or legal obstacles, work on the the initial fuel has been delivered and Clinch River plant could begin next the reactor started up. only the non-
Tokamak fusion test reactor’
Ohmic heating coils
Shielding
/
/
Variable curvature -coils
I
I
Neutral beam /
I
Vacuum vessel
E uilibrium f i j d coils
Vhetokamak will belheli~~lm~gn~licl~rion~y~te~inlhe U.S. capable olproducinglurionenergyi?any~ignilicanlquanlihl.l t i ~ ~ c h e d ~ l ebe dto Wwational at Princeton in 1982 and will cost an estimaled $239 million
1132
Environmental Science 8 Technology
radioactive materials deuterium and lithium must be provided; no further tritium would be transported to or from the plant. The only source of radioactive waste from an MCR is the activated reactor materials. Fusion reactions emit very energetic neutrons (14 MeV); while most of them would react with the lithium in the blanket to produce tritium, some would unavoidably react instead with structural materials near the core. Because of the strain put on these materials by the intense neutron flux and extreme temperatures, some components would have to be replaced at periodic intervals; and because many of the radioisotopes present in the worn-out components have long half-lives, they would have to be stored in isolation. The isolation time varies with the material, but austenitic stainless steel, the most likely material for the first commercial reactors, would require isolation for several thousand years. By far the major sources of radioisotopes in the FBR are the fuel and blanket elements. As described above, in the course of operation of an FBR, a wide variety of fission products (the fragments into which 239Punuclei are split) accumulate in the core. When the spent fuel is removed for reprocessing, these fission products, virtually all of which are radioactive to some degree, must be separated from the uranium and plutonium so the latter can be recycled into fuel. Also removed are the “actinides,” or isotopes of heavy elements, which are not usable in fuels (i.e., neptunium, americium, curium, and about 1% of the plutonium and uranium). Actinides and fission products comprise the radioactive waste of an FBR and require tens of thousands of years of isolation. Radioisotopes are extremely variable both in their toxicity and in their rates of decay; thus, it is not of much use to speak of total inventories of radioactive materials. A sounder basis of comparison for MCRs and FBRs is the biological hazard potential, an index of the hazard of radioisotopes to human health. The biological hazard potential for a given radioisotope equals the number of curies present (in the reactor, in a given volume of waste, in a hypothetical release, etc.) divided by the amount of air or water required to dilute it to the maximum concentration allowed by federal regulations. A study released in 1977 by the International Institute for Applied Systems Analysis of Laxenburg, Austria, compared the biological hazard po-
tentials of MCRs and FBRs of similar features of the two nuclear options, size and materials, broken down by A certain amount of radioisotopes inhalation and ingestion hazard, as a would be released to the air and water function of time after reactor shut- by MCRs, FBRs, and the FBRs’ down. The inhalation hazard is more fuel-cycle plants in the normal course important before long-term waste of operation. The only substance of storage, when the potential exists for concern for MCRs is tritium; tritium airborne dispersion due to a mishap; would also be released by FBRs and after long-term storage, the only dis- their reprocessing plants, but their inpersion pathway for radioisotopes is ventories, and thus the controls rethrough groundwater, and thus the quired, would be far lower than for ingestion hazard is the only relevant MCRs. Tritium is extraordinarily hard index. The study concludes that, on the to contain, due to its ability to perbasis of reactor inventory alone, the meate heated metal. Once it encouninhalation hazard is -10-100 times ters water in the steam loop, it oxidizes, greater for an FBR than for a stain- becoming far more hazardous to man less-steel MCR, up to the point of fuel (by a factor of 200) and, at least from reprocessing. Beyond this point, the a cost standpoint, unrecoverable from ingestion hazard is greater for FBR the water. In order to meet the Nuwastes by factors ranging from -2, clear Regulatory Commission’s expojust after reprocessing, up to -200 at sure criterion for fission fuel cyclesthe end of 1000 years. The cumulative 170 mrem at the site boundary-tribiological hazard potential of radiotium release from an MCR would have isotopes, integrated over the lifetimes to be kept to an average of 350 Ci/d; of the various isotopes produced, was systems that promise control an order found to be -10 times greater for the of magnitude better than this goal have FBR than for the MCR ( I ) . been designed but, obviously, remain Note, however, the above figures to be proven (3). represent a “worst case” for the MCR While the FBR fuel cycle would with respect to waste. With the FBR, release far less tritium to the environmost of the waste consists of fission ment than would the MCR, unlike the products, the quantity and radioac- MCR it would also release a host tivity of which are fixed by the capac- of other radioisotopes, a-emitters ity of the reactor and the random out- (238-242pu, 241,243Am, 242,244Cm) as comes of fission reactions, respectively. well as @-emitters other than tritium With fusion, on the other hand, the (14C, 55Kr, 129,1311, 133Xe).Based on quantity and radioactivity of the acti- experience with pilot-scale facilities, vation products can be significantly controls to within EPA exposure limits reduced by the use of materials less seem to be achievable for both a- and prone to neutron activation than p-emitters but, like tritium control for stainless steel: Niobium and alloys of MCRs, remain to be proven in comvanadium, titanium, and aluminum ercial-size plants ( 3 ) . are all potential candidates for more FBR wastes are more susceptible to advanced MCRs. accidental release than are wastes Probability of release. The biologi- from the MCR. All the radioactive cal hazard potential refers only to the waste produced by an MCR would be size of the radioactive inventory, of in solid form: namely, the neutroncourse, and says nothing about the activated structural components. FBR probability of its release. The problem waste, on the other hand, emerges is that we have no operating experience from the reprocessing plant as an with commercial-scale MCRs or acidic liquid and must radioactively FBRs, and thus no actual data on “cool” in tanks for several years before which to base estimates of risk. it can be vitrified and placed in longMoreover, while basic FBR technology term storage. Liquid wastes are obis now in hand, this does not by any viously more difficult to contain safely means rule out refinements and im- than solid wastes. provements in the near future, particBecause FBRs entail far more ularly with respect to safety devices. handling and transporting of radioacAs for the MCR, the risk picture is far tive fuels, the risk of accidental FBR more uncertain: A variety of coolants, f u e l release is much greater than for blanket materials, and reactor con- MCRs. Once the initial charge of trifigurations remain under consideration tium is delivered to an MCR, from for the demonstration facility ( 2 ) . (As then on the only time radioactive masuch, fusion presents a unique oppor- terials would be handled outside the tunity for biomedical and environ- plant would be when structural commental scientists to suggest ways to ponents had to be replaced, at intervals reduce risk.) With those caveats in of about two to 10 years. Again, they mind, however, we can make general are in solid form and thus can be observations based on the intrinsic compacted and stored directly. The Volume 15, Number 10, October 1981
1133
FIGURE 2
schematic of a nquld d u m fasl breeder power plant
FBR fuel cycle, on theother hand, involves at least four distinct locations: Fuel is manufactured at a fabrication plant and transported to the reactor; spent fuel is removed from the reactor, at the rate of %-‘I2of the core elements per year, and transported to the reprocessing plant; the spent fuel is separated, and the uranium and plutonium are returned to the fabrication plant; the liquid waste is transported to a disposal facility. Unlike FBRs, MCRs pose almost no risk of a breach in containment due to meltdown or explosion. In an FBR, as in an LWR, in the event of a coolant loss and a failure of backup control systems, the heat of decay of the fission products cwld build up to produce a core meltdown. Unlike the LWR, the FBR is designed to run on “fast” neutrons; therefore, reactivity in the core increases rather than decreases in the absence of coolant. Ultimately, if backup control systems fail, the core could conceivably go on to explode with the force of up to a fraction of a ton of TNT. Any imaginable mishap in an MCR would result in a failureof plasma confinement, thus dousing the reaction. But even if all the fuel in the plasma at any given time could somehow react in a few seconds, the energy released would merely be absorbed by the blanket with a minor rise in temperature (-100 “C). The only sources of decay heat in an MCR are the structural activation products; in the ii3h
Envlronmental science a Technology
event of a coolant loss, the resultant temperatures would be one to two orders of magnitude lower than in an FBR (4). It is expected that enough of this heat would be removed by thermal radiation and conduction alone to prevent reactor damage. The most straightforward means of producing and recovering tritium in an MCR is to use liquid lithium as both blanket material and primary coolant. But the problem with both liquid lithium and liquid sodium, the FBR coolant, is their extreme reactivity in the presence of air or water; under favorable conditions, both lithium-air and sodium-air reactions can produce flame temperatures hot enough to melt many reactor mateiials, stainless steel among them. This could lead both to a breach in reactor containment and to a mobilization of activation products by oxidation of structural materials (5). For this reason, a number of relatively nonreactive forms of lithium are under consideration for MCRs, including solid blanket media, such as Liz0 and LiAIOz, as well as other liquids such as Li-Pb eutectic. Helium is the most likely primary coolant for use with solid blankets. Potential for nuclear weapons proliferation. What sets FBRs apart from all other energy alternatives, even LWRs in their current mode of operation in the US., is the presence of “weapons-grade” fuel-namely, pure 239Pu-in its fuel cycle. It has been
repeatedly demonstrated that an undergraduate-level knowledge of nuclear physics and mechanics is all that is required to design an atomic bomb with a reasonable chance of exploding, using only declassified information and specifying parts available from hardware suppliers. The only item that is currently unavailable to the ordinary citizen is z39Pu or some other fissile material. LWR fuel itselfcontains too low a percentage of fissile nuclei (235U) to make a workable bomb. While 239Pu is produced in today’s LWRs, chemical reprocessing is required to separate it from the other, nonfissile isotopes in the spent fuel. On thegrounds that it increased the riskof weapons proliferation, the Carter administration imposed a moratorium on spent-fuel reprocessing in the US. and tried to discourage its growth in Western Europe and Japan. To date, LWRs in the U S . continue to operate on a “once-through” fuel cycle, with spent fuel retrievably stored in ponds at reactor sites. Other nations are forging ahead, however, and largescale plant expansions are underway in France (La Hague), the U.K. (Windscale), and Japan (Tokaimura) (6). Since the raison d’etre of the FBR is that it produces its own supply of 239Pu,there is no point in building an FBR unless the 239Puit produces can be recycled into fuel. Thus, a decision to go ahead with FBRs is also a de
facto decision to lift the US.moratorium on reprocessing and, as a consequence, put large amounts of weapons-grade plutonium into circulation within the US.The flow of plutonium through a single lOOO-MW, FBR would be at least 1500 kg/y. The spectre of the plutonium fuel cycle is ominous not only with respect to the consequences of diversion of weapons-grade material, but also with respect to the methods necessary to prevent its diversion and the implications o f these methods for civil liberties. Positions on this question have predictably been staked out at both extremes, with the pronuclear forces waving it away with vague references to technological fixes and the antinuclear forces conjuring up visions of a police state. But even moderate observers, including the more reasonable representatives of the nuclear industry, concede that, at the least, powers of search and seizure, pre- and postemployment checks, and both open and covert surveillance would be required to secure weapons-grade material against diversion ( 7 ) . The most vulnerable points of the FBR fuel cycle are the transport routes between the reprocessing and fabrication plants and, to a lesser extent, between the fabrication plant and the reactor. It has been proposed to reduce the risk of 239Putransport by locating the entire fuel cycle in a single, large site; however, since one set of recycling plants, of optimal size, is adequate to service at least 40 GW, of capacity, such an “integrated fuel-cycle facility” would have to contain at least 40 lOOO-MW, FBRs to be economical. While such multireactor facilities may be the only reasonably secure way to operate an FBR economically, they pose massive environmental impacts as discussed below. There are fusion-based as well as fission-based weapons, of course; the “hydrogen bomb” derives its power from fusion. But the situation with respect to materials and knowledge is reversed. Fusion bombs are far harder to design and build, and their spread has been limited not by a lack of fuels, but rather by a lack of knowledge. Any group or nation sophisticated enough to manufacture a fusion bomb would almost certainly be sophisticated enough to produce fuel for it without access to an MCR. Moreover, the knowledge entailed in magnetic-confinement reactors is not relevant to bomb design, as reflected by the fact that all magnetic-confinement research has been declassified since 1958 by international agreement. Inertial confinement remains classified, how-
ever, because it does have relevance to weapons design. Other environmental problems While the hazards of radiation and (for the FBR) weapons proliferation are unquestionably the issues most critical to the future of nuclear energy in the U S . , there are a number of other environmental issues which are not peculiar to nuclear energy. Thermal waste. The first FBRs and MCRs would drive the same type of steam turbines now used in LWRs and fossil plants, at a similar power conversion rate of -40%. The balance of thermal energy produced in the reactor would be rejected to the cooling water flowing through the condenser. Since “once-through” cooling is not expected to be available 20-30 years from now, systems based on either artificial cooling ponds or “wet” or “dry” cooling towers are expected to be the norm. The only advantage MCRs may have, with respect to thermal waste, is that they promise to be qualitatively safer than FBRs; if they are perceived as safe enough to site near urban areas, the heat they reject could be “cascaded” to lower-temperature uses, such as space heating. Materials use. FBRs are comparable to LWRs and coal-fired plants in terms of structural materials, but the nuclear islands of MCRs (but not the balance of the plants) would be about four times more materials-intensive over their lifetimes, due both to their lower power density and to the shorter lifetimes of some reactor components ( 3 ) . Moreover, some of the materials contemplated for advanced MCRs, in particular vanadium and niobium, are relatively scarce in the U S . On the other hand, at an energy conversion rate of lo%, an array of photovoltaic cells could require up to -1 0 times the amount of materials in an FBR (8); improvements in photovoltaic materials and the use of concentrators could reduce this discrepancy significantly. Land use. FBR and MCR sites would each occupy 1- 1.5 km2-comparable to an LWR site but about half as large as a coal-fired plant site. The aforementioned photovoltaic system would require -100 times as much surface area, although it would not preclude multiple use of the land, as would coal and nuclear plants; again, improved photovoltaic conversion would lower this discrepancy. While the land despoiled by mining of fuel would be on the order of fractions of (ha/y)/GW, for both FBRs and MCRs, and a few (ha/y)/GW, for LWRs, land disturbance due to surface mining of coal is (0.5-1.5 km2/
y)/GW, (for typical western and eastern seams, respectively) ( 9 ) . Yet, if the nonradiological impacts of both long-term nuclear options seem unremarkable, this would only be true if they are dispersed in the same manner as are nuclear plants today, i.e., from one to four reactors per site. In the case of FBRs, this would require that the public be amenable,to the frequent and widespread transport of weapons-grade fuel on open roads. While minds can and do change over time, from today’s vantage point, widespread opposition to such a prospect seems a virtual certainty. For this reason, the aforementioned integrated fuel-cycle facility concept is sure to be advocated as a means to lower the risk of plutonium diversion. Such a facility would have some advantages over dispersed sites, notably a stable work force. Construction of reactors in a 40-FBR facility could be staged at yearly intervals, so that by the time the last reactors were completed, the first ones would be due to be replaced. The “boomtown” syndrome, and its consequent fiscal and social impacts observed in large, isolated energy projects, would thus be eliminated. But the land use and waste heat impacts of an integrated fuel-cycle facility would be enormous. A Nuclear Regulatory Commission study estimated that a 40-FBR facility, employing an artificial lake for cooling, would cover as much land as the city of Washington, D.C., and discharge 10 times as much waste heat. Use of “wet” cooling towers instead of a lake would reduce the land required by up to 80%, but not the waste heat discharged (IO).The heat produced by a 40-FBR integrated fuel-cycle facility would cause localized changes in meteorology, Le., more clouds, fog, and rain, increased temperatures, and the potential for more frequent storms. Moreover, at an evaporative loss rate of (-1 m3/s)/GW,, wet towers serving 40 FBRs would consume 40 m3/s. Given a withdrawal limit of lo%, only a few rivers in the US.could sustain such a demand. Thus, most such facilities would have to either be sited on the coast, unquestionably a poor use of valuable land, or use dry towers, at some penalty in cost. The larger picture What has been presented thus far is no more than a cursory scan of the most salient environmental issues posed by FBRs and MCRs. Yet, there is a far more basic question we must face before we can hope to utilize either technology on a wide scale: Do we Volume 15, Number 10, October 1981
1135
I
!
put^-
McKesson
tOWOrkfOryou,
--
Priority pollutants-GUMS NPDES and RCRA permits Total organic halides and TOC Hazardous waste characterization hmpling -soils. effluents, ground water
* Soils/sediments/leachates Why rot join the many ccinpanies that have put ForemMt-h+zKesm to work for them. Call of M i t e for m r e information. Foremolt-McKesm RescirCh Center 6363 Clark Ave.. Dublin, CA94566 (415) 828.1440 CIRCLE 3 ON READER SERVICE C A R 0 1136 Environmental Science 8 Technology
want it in the first place? Or, more precisely, do we want it enough to incur the risks it poses? For all the billions of dollars spent on the LWR in this country, we have yet to make this most basic decision and, consequently, find ourselves unable either to get on with this technology or give it up. The problem is that risk defined in a societal context is perceived in an individual context. In other words, while a majority of us may favor nuclear energy in the abstract-as evidenced in a number of state referenda-hardly any of us want a reactor in our own backyard. The fact that countries such as France and Britain, as well as the Soviet Union, have strong nuclear programs and are much further along the road to FBR utilization is often taken to mean that they have in some way solved or escaped this problem. In reality, the problem is not escapable or solvable; France and Britain-impelled in large part by an energy situation far more precarious than ours-have simply made the decision that nuclear energy is in the national interest and that the national interest is to prevail over individual or group concerns. As a result, the system of financing, licensing, and building new reactors is, compared to U S . standards, a fast track indeed. The national government defines the nuclear program; the national government builds (and guards) the plants: and the lay Aizenry is excluded from the regulatory process. The only recourse for one who objects either to a particular project or to nuclear energy in general IS to vote the government out at the next election (I I). On the other hand, the US.system Jf (relatively) weak and decentralized :overnment, undercapitalized private Industry, and regulatory hearings open to myriad "intervenors" may never %llow for another LWR, let alone FBRs, which pose most of the risks of LWRs plus a few others-notably Autonium diversion. Public reception If MCRs is unknown at this point; but while they are inherently much safer .han FBRs, their potential impacts are mly comparatively minor. The coniequences of a mishap at an MCR, iuch as a lithium fire resulting in the .elease of tritium and volatized actiiation products, could be quite serious; and radiation exposure is a risk to which most of us have a strong, subconscious aversion, which can be eliminated only partly by scientific argument (12). Although the European model has obvious advantages in overcoming public resistance to national goals, it also runs counter to
some very basic American traitsindividualism and the mistrust of authority. The future 'of FBRs and MCRs in the US.may ultimately depend on how far we are willing to compromise in return for inexhaustible, storable energy. Acknowledgment This article was read for technical accuracy by Charles C. Coutant, Oak Ridge N a tional Laboratory, Oak Ridge, Tenn. The research for this article was performed under theauspices ofthe US. Department of Energy by the Lawrence Livermore Laboratory under Contract W-7405-
Eng-48.
References (1) Hifele. W..etal."Fusionand Fast Breeder Reactors"; RR-77-8; International Institute for Applied System Analysis: Laxenburg. Austria. 1977. (2) Clarke, J. F. Science 1980,2/0,967-972. (3) Kulcinski. C. L., et 81. Am. Sci. 1979.67,
78-89.
(4) "Environmental Readiness Document: Magnetic Fusion"; 'Teknckron Research. Inc.. Deuartment of Enerev: Washinetan..~ D.C.. 1980, draft in press. ( 5 ) Holdrcn, J. P. "Contribution of Activation Pralucts to Fusion Accident Risk Part 1. A Preliminarv Invertisation": llCRI.-R1694 ~... . Lawrence iivermo; N&A i a toratory: Livermore. Calif.. 1980. (6)I), Salaff, S. Bull. At. Sei. 1980, 36(9). IS-
".
~.
~
L...
_- __
(7) Sicghart. P. Bull. At. Sci. 1980, 36(5). I?.?
