Science in Christian Perspective
From: JASA 32
Courtesy Of Sierra, The Sierra Club Bulletin.
For many determined proponents of nuclear power, finding a solution to the nuclear-waste problem has become the bottom line. Even after Harrisburg, they have faith that reactors can he made safe, if only the nuclear industry will shape up and follow the advice of experts. But without a solution for the waste-disposal dilemma, legions of smoothly running reactors will only compound the problem. Radioactive wastes from commercial and military production are already more abundant than all the water in the world's oceans could dilute without risking dangerous concentrations of radioactivity in marine organisms and sediments.
The tragic limit over which human hubris may have tripped is that nuclear waste stays poisonous practically forever; nobody has vet invented a container for it that won't leak, sooner or later. Environmental concern about radioactive waste has focused on four areas: the difficulty of containment, the different kinds of radiation, different forms of existing waste and the locations of radioactive waste.
For more than 35 years nuclear promoters have been saying that safely isolating nuclear wastes would be easy. Until very recently they were saying it would be so easy' that it wasn't necessary to bother with et. But even before the valve failed in the Three Mile Island plants cooling system, nuclear engineers were becoming less confident about their ability to contain ionizing radiation under any and all conditions.
In mid-March the federal government's Interagency Review Group (IRG) on nuclear-waste management reported to the President that the scientific feasibility of government's and industry's favorite waste-disposal concept, dry storage in geologic repositories constructed deep in salt beds or hard nick, "remains to he established." This admission, though pitched in a low key, strikingly contrasts with an earlier draft's optimism about the feasibility of geologic storage for thousands of years. The final report, produced by representatives of fourteen federal agencies, further advised the President, who is expected to make the key' decision (01 geologic storage before this article is published, that "the preferred approach to long-term nuclear-waste disposal may prove difficult to implement in practice and may involve residual risks for future generations which may be significant." The report stressed that the safety' of disposing of high-level wastes in mined repositories could only be assessed by specific investigation at particular sites.
So far, only a few potential waste-repository sites have been subjected to rigorous geologic investigation: bedded salt deposits near Lyons. Kansas; granite formations in Sweden; and salt beds near Carlsbad, New Mexico (the Waste Isolation Pilot Plant, WI PP). The Kansas salt beds were found to be riddled with holes from con1nmercial exploratory' operations. In February, geologists advising the Swedish Nuclear Power Inspectorate gave a failing grade to a proposed storage site in granite. Geologists have raised basic questions about the safety' of storing radioactive waste in any salt formations. The WIPP site, the most thoroughly studied by the United States Department of Energy (DOE), is currently the focus of heavy' criticism from environmental scientists as well as from government nuclear scientists outside the DOE.
How Low is Low Enough?
So far, all the design concepts for geologic repositories plan for what at best amounts to slow' leaks and not for zero discharge of radioactive wastes. But this is not enough. A scientific consensus appears to be forming that any amount of radiation can cause cancer in man.
An unverifiable amount of cell damage is caused by already existing "background radiation" from cosmic rays, from emanations of the natural uranium and thorium in the earth's crust, and from residual radiation from certain natural elements in granite and other rock. Estimates of this natural radiation range from 100 to 250 millirem per person a year for whole-body doses Since the average medical and dental exposure is 70 millirens annually, human exposure can quickly multiply above the natural background level with no increase from nuclear power or weaponry. Even a transcontinental airplane flight acids four millirem to the body's burden of exposure.
As more research is published on how much radiation is "safe" for human beings, scientists learn more about how unsafe even tiny increases above the background level can be. With no control possible, the damage done by the latter cannot be measured. Even lung cancer induced by tobacco smoking may be traced to the effect of particles of polonium, a radioactive element collected from the air by tobacco leaves and deposited in the lungs of smokers.
Different kinds of ionizing radiation-labelled alpha, beta, gamma and neutron-pose different hazards to living cells. Alpha-emitters such as polonium and fissile plutonium 239 can be transported in any kind of sealed container, even pockets or briefcases, without harming anyone because alpha particles can travel only short distances and cannot pass through the protective outer layer of human skin. But if an alpha particle is inhaled into the lungs, or otherwise given a chance to reach internal organs, it adheres where it is deposited and damages cells by accumulated radiation over the years. As little as 10-100 micrograms of plutonium 239 in the lung is probably enough to produce a 50% chance of inducing lung cancer. Reactor-grade plutonium is so highly refined that one tenth as much will do the same.
Alpha-emitting elements have very long half-lives; they include most of the actinides: actinium, thorium, protactinium, uranium, neptunium, plutonium, americium, curium and heavier elements, many isotopes of which are fissile. (Transuranic elements, a classification often used in the media, are actinides heavier than uranium.)
Beta particles, more than 7000 times lighter than alpha particles, can travel farther and penetrate skin more easily. Nevertheless, like alphas, they are most dangerous absorbed inside the body. Most products of nuclear fission, like those that threatened the countryside around the Three Mile Island reactor in March, emit beta radiation. Two that have received much attention are iodine 131, which concentrates in the thyroid gland, and strontium 90, particularly dangerous for infants and children because it is most readily absorbed by bone. Another betaemitter, tritium, is a radioactive form of hydrogen that, as a constituent of-water, spreads easily in the body and is therefore more easily diluted and less toxic. Radioactive krypton, routinely released from reactors, diffuses through the atmosphere and adds to the average total external dose of low-level radiation received by the public.
Most fission products also emit gamma rays. Like the neutrons produced by nuclear fission and fusion, gammas penetrate through skin, sinew and bone-as well as through heavy lead, steel and concrete shielding. X-rays are a lower-energy form of electromagnetic radiation, similar to gamma rays, that can penetrate the body and can also cause biological damage. Doctors and dentists are now encouraged to keep X-rays to a minimum.
New information is released almost daily concerning the heightened cancer incidence among workers exposed to low-level radiation in uranium mining and milling, military reprocessing (which recovers uranium fuel used in nuclear-powered ships and plutonium for bomb fabrication), nuclear shipyards, soldiers involved in nuclear bomb testing and civilians caught in its downwind fallout. Recently Ralph Nader's Health Research Group asked President Carter to act on a National Academy of Sciences recommendation that allowable occupational exposure to low-level radiation he reduced ten fold, from 5 rem to 0.5 rem per year, the equivalent of 20 to 50 times the level of exposure of a chest X-ray.
The Nader group cited a British study that showed increased chromosomal damage in workers exposed to only 2 to 3 rein a year. Dr. Alice Stewart of the University of Birmingham, who has been working with a study of 35,000 living Hanford workers, says that prolonged low-dose exposure leads to proportionately more damage than a single, larger dose. At lower doses., the body is able to repair slightly damaged cells well enough for them to reproduce, passing on the damage to succeeding generations, or to make other damaged cells that weaken the body's resistance to disease and injury. Children born in southern Utah during the years when atomic bombs were exploded above ground have been reported by a University of Utah medical team to suffer 2.5 times the number of leukemia deaths as children born before and after the testing.
For 22 years the accepted wisdom has been that annual exposure of 170 millirem above background radiation levels was a permissible level for the general population. However, in 1977 the Environmental Protection Agency suggested 25 millirem as the annual limit. The Nuclear Regulatory Commission (NRC) has adopted that figure as the permissible dose to the public created by the nuclear fuel cycle.
Meanwhile cancer mortality is on the rise in the United States among all age groups. Chemical air and water pollution, food additives and increased ionizing radiation from bomb-test fallout, medical procedures and nuclear reactor operation all appear to he culprits, each synergistically augmenting the carcinogenic effect of the others. Given this knowledge, it seems evident that the release of carcinogens into air, water or the food chain should he reduced rather than permitted to escalate over time-as ionizing radiation from increasing quantities of badly stored wastes is all too likely to do. (The radio
activity of commercial waste began to exceed that of military waste last year).
The problem of containing radiation from nuclear wastes begins at the uranium mine and at its adjacent mill, where uranium-bearing rock is crushed and processed and tailings are chemically separated from uranium. Currently 16 uranium mills in the United States process 10 million to 15 million tons of ore annually. Good ore contains 0.2 uranium by volume. The rest is tailings; about 140 million tons have accumulated so far in the United States, almost uranium-free--but not radiation free. Uranium, decaying through the ages, has produced thorium and thorium's "daughter" radioactive elements, including radium and radon, which are sources of gamma radiation.
Because of thorium 230's long half-life (180,000 years), its daughter products will remain active pollutants for hundreds of thousands of years. N 01 until fifteen years ago, when alert public-health personnel discovered a higher incidence of cancer in people who lived in houses built with or on mill tailings, was their use in the construction industry and for road building in the West curtailed. But the problem with mill tailings persists; tailing dumps cover many acres of ground. Wind whips the tailing dust high into the atmosphere, where it is carried for long distances.
Covering existing tailings with asphalt or burying them and safely sequestering new tailings is an expensive project the Department of Energy's Nuclear-Waste Management Program is currently working on. The progress of its efforts to protect the atmosphere from radon, and groundwater from leached radium, will need continued public attention.
As part of its study of nuclear waste, the IRE; postulated several energy futures for the nationdifferent estimates of energy use that would result in varying amounts of nuclear waste. Under IRG's "Case 1" postulate of 148 gigawatts (GW) of installed nuclear electric generating capacity in the year 2000 (the higher Case 2 scenario projects 380 gigawatts-today the U.S. has about 50 GW of nuclear capacity), 1.9 billion tons of tailings will have been produced by then. Legislation is before Congress that would authorize EPA to issue standards and criteria for milltailings disposal, and would establish the Nuclear Regulatory Commission's (NBC) licensing authority over active sites and DOE's authority over inactive sites. Assigning authority, however, cannot guarantee a solution of the gargantuan problem posed by the tailings.
Low-Level Wastes (LLW)
Next to mill tailings, low-level wastes, which contain small amounts of radioactivity and require no shielding, produce the largest physical mass of "nuclear junk" to be disposed of. They start accumulating at the mine shaft. Used equipment and such miscellaneous debris as gas filters, lab coats, paper towels and some liquid wastes solidified in concrete continue to accumulate through the entire fuel cycle. Some of it-trucks, parts of decommissioned reactors-is very bulky.
During most of the history of military and commercial use of the atom, low-level wastes have been buried in shallow trenches. A few years ago at the burial site at Maxey Flats, Kentucky, plutonium was found to have migrated as far as two miles from the site. Of six burial sites for commercial wastes, two (West Valley, New York, and Maxey Flats) are now closed. A third site, at Sheffield, Illinois, is already filled to its licensed capacity. The NRC had to order the Sheffield operator to continue patrolling fences and maintaining trenches after the site had been, in effect, abandoned.
Currently, commercial LLW is buried at Barnwell, South Carolina (where the state government limits quantities), at Beatty, Nevada, and at Hanford, Washington. The DOE has fourteen other burial grounds. No coordinated national program for LLW management exists yet. Niagara Mohawk Utility has applied for a permit to build a commercial LLW incinerator at a reactor near Oswegn, New York, but the local Sierra Club is worried that scrubbers won't keep radioactive cobalt and cesium out of the air.
The DOE has selected a contractor to build an incinerator at the Idaho National Engineering Laboratory. Intended for operation by late 1986, the incinerator will take eight years to process the existing backlog of LLW. The rock-like radioactive slag residue will go to ... wherever the government may decide to build a permanent waste repository.
Almost all low-level wastes are either solids or made solid with concrete, but some low-level liquid wastes at a DOE facility at the test site near Mercury, Nevada, are pumped 1000 feet do,,,,n into an underground cavity created by a nuclear explosion. Unknown quantities of lowlevel liquids were solidified in cement and dumped at sea in the early days of nuclear development. It is worth asking whether the Nevada test-site disposal of liquid wastes could pass the skeptical scrutiny geologists, geochemists and hydrologists are currently giving to concepts for using geologic formations to isolate spent fuel and high-level wastes encased in steel and titanium.
Intermediate Waste Liquids
Intermediate-level waste liquids produced at the Oak Ridge National Laboratory are injected into a deep underground shale bed after first being mixed with grout. The grout solidifies and is intended to fix the wastes in place. Whether it does or not, over the very long periods that some of the waste remains radioactive, will remain in question for many thousands of years.
Transuranic (TRU) Wastes
Since both TRU waste (which contains more than ten nanocuries of transuranic activity per gram) and high-level waste contain long-lived actinides, they pose similar lung-term containment problems and should be disposed of with equal care. Yet all existing commercial TRU waste is buried, along with much larger volumes of associated materials, in shallow trenches at commercial burial sites (except at Barnwell, where the government of South Carolina ruled against it). Only Hanford continues to receive commercial THU waste for burial.
The transuranic content of the DOE's THU waste is mainly plutonium. Until recently most of it was buried, but several years ago, at Hanford, enough plutonium was found to have migrated from one burial trench to make a chain reaction possible. As a result, since 1970 DOE has stored THU waste in a retrievable form. The major purpose of the proposed WTPP disposal site is to store DOE THU waste produced at Hock) Flats in the fabrication of bombs and currently stored at the Idaho National Engineering Laboratory. The state of Idaho has repeatedly pressured DOE to remove this waste.
The fact that radioactive particles can travel through the air has been widely known since Hiroshiosa. It became more immediately apparent at Three Mile Island, What is less widely known is that nuclear reactors routinely vent into the air small amounts of gaseous radioactivity, including the nuclides krypton-85, xenon-133, iodine-131 and carbon-14. To reduce air pollution as much as possible, airborne emissions from reactors, spent-fuel storage, fuel reprocessing, weapon-related activities and waste treatment processes such as incineration and vitrification are filtered through sand, fiberglass and other appropriate materials that themselves then become radioactive wastes.
A supposedly typical DOE chart of a filtration system in a spent-fuel reprocessing facility claims 99.97% efficiency before the gases go up a 200-foot stack, Emissions of radio-iodine are controlled by special absorbers. The DOE Nuclear Waste Management Program aims to develop "new capability in areas where more restrictive standards seem likely to apply in the future." It seems a virtuous intention.
High-Level Wastes (HLW)
High-level wastes are either spent-fuel assemblies or the fission products and actinides that remain in spent fuel after plutonium and uranium have been recovered in reprocessing. Approximately 73 million gallons of liquid high-level wastes, among the must toxic and hazardous substances known, are now on hand awaiting a permanent method of disposal. They are in various forms: extremely corrosive acid liquids; salt cakes; sludge in underground tanks; and granular, calcined solids stored in underground bins. They consist of fission products, including strontium 90 and cesium 137 (30-year half-lives), actinides and certain other radioisotopes. The relatively short lifetimes of the fission products produce rapid disintegration; most of the wastes' heat and radiation are dissipated within 600 years of their existence. But the slower disintegrating actinides may persist for millions of years.
Originally, HLWs are liquids produced during the reprocessing of defense-program reactor fuel or the commercial reprocessing of spent fuel. Since the United States' only commercial reprocessing plant, owned by Nuclear Fuel Services and located in West Valley, New York, has been closed, high-level wastes are new produced only at DOE military facilities in Savannah River, South Carolina; Richmond, Washington; and Idaho Falls, Idaho.
New double-shell steel tanks are being constructed to replace leaking tanks at the Hanford Nuclear Reservation and to provide additional interim storage. High-heatgenerating cesium-137 and strontium 90 are being isolated from other wastes and encapsulated separately to make handling the remaining wastes easier.
Problems other than leakage have arisen with high-level waste storage. Waste at West Valley neutralized with an alkaline solution has turned out to be very difficult if not impossible to remove from a carbon steel tank. After a dispute arose between the state of New York and the federal government over who was financially responsible for 600,000 gallons of waste and for the cost of dismantling the Nuclear Fuel Services plant at West Valley, both parties arrived at a tentative agreement that has been rejected by environmental groups. Under the agreement, DOE would accept major financial responsibility for West Valley and would use its spent-fuel pool to store up to 1000 tons of spent fuel, and its waste-burial grounds would be reopened. Environmental groups, including the Sierra Club's Nuclear Waste Task Force, can he expected to mount an effective campaign against any new scheme to encourage the accumulation of nuclear waste by storing it at West Valley while means for its disposal remain unknown.
Since the United States has deferred indefinitely reprocessing of commercial spent fuel, owing to concern over keeping plutonium out of the hands of hostile military powers or terrorists, commercial facilities for glassifying-vitrifying-wastes have not been developed here, as they have been at France's Cogeuma plant and soon will he at Britain's Windscale plant. Both plants, and the nations planning to use their reprocessing facilities, are counting on the development of geologic storage for these vitrified wastes.
Reprocessing contracts such as Cogema's promise to remove all but 0.5% of the plutonium from wastes, but experts view the promise as optimistic. Moreover, approximately three times as much americium is also left in the wastes; it decays into plutonium, so the plutonium content actually increases over the first 20,000 years. All of the other actinides and fission products are left in the reprocessed waste product. If recovered plutonium is used as fuel and is again cycled through more reprocessing, it will he added to successive waste streams to accumulate wherever the waste is stored, a fact generally overlooked by the proponents of "burning tip" the actinides.
Nuclear reactor fuel rods, each about twelve feet long, consist of a packing of uranium-oxide fuel pellets and a zircaloy casing, called "cladding." Approximately 40,000 of them are arranged in assemblies for encasement in the core of a large reactor. After about three years of fission, radioactive by-products slow down the fuel pellets' ability to sustain a nuclear reaction; the whole assembly is then considered 'spent" and removed to a water tank for cooling and storage. Each year a 1001) MW light water reactor discharges about 25.4 metric tons of spent fuel into storage pools adjacent to the reactors. Only one storage pool in the United States, operated h General Electric at Morris, Illinois (originally intended to store spent fuel for reprocessing), has accepted spent fuel from distant reactors, some 300 tons of it.
The storage pools at first were intended to store spent fuel rods for five years, but since no alternative system of storage has been devised, some spent fuel from our oldest commercial reactors has been cooling in them for 20 years. The spent-fuel rods must he carefully separated from each other to prevent the start of a chain reaction in the pool. The rods grow brittle with age; their cladding weakens; their cooling water is vulnerable to cutoff; they contain higher levels of radioactive strontium and cesium than the reactor itself; and no one in his right mind considers permanent storage in a pool a good idea, whether at the generating plant or in a very large, centralized, "away from reactor" pool. Unfortunately no one has yet developed and demonstrated a better plan.
Meanwhile, nuclear engineers have designed methods for increasing the load in existing storage pools by reracking; and some NRC spokesmen believe that the United States could continue existing and planned reactor operation with no storage other than the pools until the end of the century. According to the IEG, the U.S. has about 5000 metric tons of spent fuel now, with at least 71,000 tons anticipated by the end of the century.
From the point of view of the nuclear industry, all spent fuel is an energy resource that should be kept available for reprocessing into plutonium and uranium to be refabricated into nuclear fuel. Nuclear critics worry about keeping spent fuel cool and containing its radiation while adequate permanent isolation technologies are developed.
Decontamination and Decommissioning
All operating nuclear reactors and all nuclear-fuel processing facilities, including buildings, will sooner or later become nuclear wastes. Nuclear reactors themselves have an expected operating life of 30 to 35 years. The DOE has identified 560 nuclear facilities currently obsolete or expected to become obsolete in a few years. Nobody really knows how they ill be decommissioned-if they can be-or how much it would cost. Estimates of decommissioning costs are not included in the rates of utilities using nuclear power. Closing obsolete facilities and guarding them forever "mothballing"-has been suggested. So has encasing them in concrete. Neither idea sounds like a winner.
Dismantling the reactors is probably the only option that will he acceptable to environmentalists, but it does not answer the question of where and how the chopped-up reactor will be contained. The NBC's Peter B. Erickson is quoted in Business Week as saying that any mothballing plan must take into consideration an entire range of elements, including short-lived isotopes such as cobalt 60, dangerously radioactive for 100 sears, and such longlived substances as niobium 94 and nickel 59, with halfl-ives of 20,000 and 80.000 years, respectively, that require isolation for at least a half-million years.
Nuclear reactors looming through the mist on hillsides or the coastal horizon look as sturdy (and as eerie) as Stonehenge; 72 commercial reactors were operating in the United States at the time of the Harrisburg accident, with over 500 operating or in the planning stages worldwide. Like the other nuclear wastes, they wont go away by themselves.
The two plans for intermediate and permanent storage of high-level wastes or spent fuel have received considerable attention: the Swedish plan for storage in granite and the WIPP site in salt. They aim, at best, for 100 years of absolute containment by multiple harriers of casks, clay and rock or salt. During that time sonic fission products would decay to very low levels, but long-lived materials, the heavy-metal actinides capable of fission themselves, will probably slowly leach through corroded casings and dissolved glasses, through fissures in rock and underground aquifers into rivers and waterways. Eventually they will reach the oceans.
DOE is considering another plan to emplace nuclear wastes in clays on the sea floor far from any continental boundary. In case of a failure of containment, radioactive pollutants could reach the oceans even sooner.
The gamble with any plan yet proposed for storage of nuclear wastes is (1) that none of our descendants will breach the repositories through war or drilling for minerals; (2) that water and heat will not concentrate fissile materials to form inadvertent nuclear reactors capable of producing larger quantities of unconfined radioactivity; (3) that ice sheets, the geologic folding of the earth, or other unforeseen processes will not uncover the wastes; and (4) that none of the anticipated processes will happen faster than expected, causing the wastes to "hobble up through the earth two decades from now because in 1979 we made a wrong technical decision," as Senator Glenn worried aloud at a hearing no the IRC recommendations. It is a most unusual gamble; no one now alive is expected to lose, if all goes according to plan -unless a sense of guilt over endangering the future for our present comfort and convenience is a kind of loss.
A thousand years ago, the finest architectural and engineering talents in the western world w eye mobilized to build cathedrals. It is ironic and disheartening that comparable talents and even more sophisticated skills must today he devoted to devising foolproof garbage dumps.