Wasting Away: Radioactive Waste Disposal is the Achilles Heel of the Nuclear Industry
by Lorna Salzman
For decades the nuclear industry has been seeking a safe method of radioactive waste disposal. As yet their search has been a dismal failure. The longer the problem remains unsolved, the less credible are assurances that an acceptable solution will eventually be found.
If any issue has the power to shut down the nuclear industry, it is the disposal of radioactive wastes. To the general public it poses a more insidious and intractable threat than any other aspect of the nuclear fuel cycle. Hostility to dumping plans continues to mount, and is hitting the industry where it hurts.
In August, the Brookhaven National Laboratory, Long Island, announced that unless bans on the transport of nuclear waste through New York City and New London were lifted, it would be forced to shut down. Unable to ship the spent fuel elements from its experimental High Flux Beam reactor for reprocessing in South Carolina, the laboratory now finds its existing storage facilities dangerously close to overflowing. Brookhaven's problems reflect the extent to which the waste disposal issue has become the Achilles' Heel of the nuclear power programme. Earlier this year, for example, the California State Legislature vetoed plans for the $3 billion Sundesert nuclear power plant after the San Diego Gas and Electric Company had failed to convince them that adequate waste disposal facilities were available. That veto resulted in a nuclear moratorium in Californiaa lead that has since been followed by several other states. Indeed the depth of public hostility over the waste issue was revealed by a Harris Poll published last Spring: whilst residents in New York State opposed the siting of a reactor near their homes by two to one, they opposed the storage of radioactive waste anywhere in the state by an overwhelming four to one.
In the face of such widespread opposition, the nuclear industry's survival clearly depends on convincing the public that it can not only contain but also isolate the wastes indefinitely. That distinction is important, for whilst it is easy to propose methods of waste solidification, encapsulation and geological burial, it is difficult, if not impossible, to demonstrate effective long-term isolation. Yet failure to do so could well bring a national moratorium on the development of nuclear power. The industry's past record of waste management hardly inspires confidence. Almost without exception, the storage of wastes has been marked by clumsy handling, incompetent inspection procedures and shoddy containment practices. Staggeringly large amounts of high and low-level wastesin addition to plutoniumhave already been leaked (sometimes intentionally) into the soil and water, resulting in irreversible damage to both public health and the environment. What then is the extent of the USA's waste problem? And how likely is it to be solved?
Uranium Mill Tailings
Milling operations crush the uranium ore, separating the uranium-238 and its small uranium-235 component from the rest of the ore and leaving posterity to deal with vast quantities of finely powdered tailing that emit the same dangerous radioisotopes as uranium itself: thorium-230 and radon-226. The latter decays to gaseous radon-222 whose radon daughters are alpha emitters which cause lung cancer if inhaled. Since the thorium-230 that gives rise to the radon has a half-life of 80,000 years (and itself arises from uranium-238 with a half-life of 4.5 billion years) these tailing will continue to give our descendents does of alpha radiation for countless generations.
From 1948 to 1968, when uranium was mined for military and commercial purposes, about six thousand miners in the US were 'significantly and needlessly exposed to radioactive gases present in the air of uranium mines' (Rand Corporation). Several hundred have since died of lung cancer and the US Public Health Service estimate that a further eleven hundred deaths can be expected. In Canada dust levels in uranium mines near Ontario were consistently above the industry's safety guidelines over a period of fifteen years; nothing was done to curtail them. Over 100 million tons of mill tailings are presently stored in huge piles above ground in the Western States and some have leached into rivers used for drinking water or have simply blown away. Incredible as it now seems, there were many cases when they were simply given away; builders used them in foundations for schools, homes, roads and public buildings, until in the 1970s it was discovered that the inhabitants of these buildings were receiving the equivalent of up to 500 chest X-rays each year from the radon gas seeping up through the floor. Many foundations were dug up and carted away , but by then much damage had been done. As for the US government, it totally ignored the health hazards of radon in its reactor licensing procedures until Robert Pohl, a Cornell University physicist, forced it to admit that they had been underestimated by a factor of 100,000.
The solution to the tailings problem is well-known: burial to a depth of 100 feet (roughly the depth of the original body of ore) so that radon gas, with a half-life of 3.8 days, can decay before reaching the surface. Since this would drastically increase the costs of commercial nuclear power, the government plans instead to turn all tailings over to the state legislatures and is trying to enact laws absolving itself from all damage to health caused by tailings, including those already accumulated.
High-level wastes, mainly consisting of spent fuel elements and acid wastes (in some cases neutralized) left over from reprocessing, emit intense radiation that requires heavy shielding. The waste elements of greatest concern are the fission products, chiefly strontium-90, cesium-137, iodine-129 and technetium-99. Iodine-129 has a half-life of 10 million years; strontium-90 of 38 years; cesium-137 of 30 years; and technetium-99 of 200,000 years.
At present the volume of high-level wastes from commercial reactors is only a fraction of that previously generated by the military, largely through their plutonium production programme at Hanford, Washington. (It is estimated that by the 1980s the military alone will have produced nearly half a million tons of high-level wastes measured in solid form). Yet in terms of the radiation hazard they represent, commercial wastes are far more dangerous: per unit of volume, fission products from the commercial programme are one hundred times greater in radiotoxicity than those produced by the military programme. At the end of 1977, the inventory of curies of important nuclides generated from military and commercial operations was about equal, by 1985, the total inventory of fission products in high-level wastes alone is expected to be 100 million curies, mostly derived from the commercial programme. One microcurie is considered the maximum permissible body dose.
The Hanford tanks, with about 71 million gallons of neutralized high-level liquid wastes (some in salt cake or sludge form) have a dismal history. Over the thirty years of military activities, 450,000 gallons of high-level waste have leaked into the soil and in some areas into the ground water beneath the reservation which adjoins the Columbia River. The leaks were largely due to the tanks being corroded by acid wastes, as well as criminally lax inspection and monitoring techniques. The largest single leak115,000 gallonscontained nearly 270,000 curies of ruthenium-107, 40,000 curies of cesium-137, 4 curies of plutonium-239, 0.6 curies of americium-241 and 13,000 curies of strontium-90. Tritium and ruthenium have both been detected in the water table; strontium-90 and iodine-131 were found in the Columbia River itself; and large amounts of plutonium, stored in outside trenches, have had to be dug up and dispersed because the government feared a spontaneous explosion. Plutonium-239 also percolated into the covered cribs outside and recent studies indicate that the concentration of plutonium in the sediment beneath the cribs is as high as 0.5 microcuries per grammefive thousand times the maximum permissible concentration in the soil. After the leaks, the wastes were neutralized but this produced a fission product slurry on the bottom of the tank which no one knows how to remove. The high-level wastes in the Hanford tanks contain up to 10,000 curies of radioactivity per gallon.
Low-level wastes can either be liquid or solid, and include clothing, filters, tools and other material contaminated with plutonium and other transuranics. They have been buried in six shallow burial grounds dotted across the United States. At the Nuclear Fuel Services site at West Valley, New York, radioactive material leached into the nearby creeks that feed Lake Erie after some of the burial trenches were flooded with water; later a study undertaken by the Wood's Hole Biological Laboratory revealed that traces of curium-244 had been found in both Lake Erie and Lake Ontario. At Hanford, low-level wastes are deliberately percolated into the soil. At Maxey Flats, Kentucky, plutonium from burial trenches was found to have migrated in the soil to a distance of two miles within a few years of dumping, confounding the experts who claimed that absorption by soil particles would prevent such movement. A recent study in Science (June 30th, 1978) reports that trace quantities of certain radionuclides (primarily cobalt-60, but also isotopes of plutonium, thorium and cesium) are migrating from both solid and liquid waste disposal pits at Oak Ridge National Laboratory (ORNL), Tennesseedespite the predominant bedrock of the burial ground being Conasauga shale, which is supposed to have an extremely high absorption capacity for most fission products. The cobalt-60 had been transported into the groundwater from the burial trenches in an organic form. The researchers, James Duguid of Battelle-Columbus Laboratory and Jeffrey Means and David Crerar from Princeton University, pointed out that organic chelates used in decontamination operations (not only at ORNL but at nuclear establishments throughout the world) in combination with natural organic acids in the soil, reduce the capacity of the soil to absorb radionuclides. Still worse, chelates increase the uptake of the numerous trace elements by plants, and thus increase the possibility of certain radionuclidesnotably plutonium-239 and americium-241entering the human food chain.
In addition, there have been innumerable losses of low-level wastes through transportation accidents. Last spring, for example, 40,000 pounds of yellow cake (uranium oxide) were spilt when a truck carrying it in metal drums collided with three horses on a deserted Colorado road, and overturned, rupturing the containers and spewing the contents a foot deep across the road.
What does one do with a nuclear power station that has reached the end of its life? What is the best way to get rid of the fifteen to twenty per cent of its contents that is still highly radioactive? As yet no one knows the ultimate technical, financial and health costs of complete reactor decommissioning. So far the twenty reactors that have been closed down in the western world have all been prototypes which have only been in operation for relatively short periods. Their radioactivity levels are only a fraction of the levels forecast for the large commercial reactors due to be closed down in the next twenty years. Even so, when a small research reactor was recently dismantled (under water to minimize radiation exposure) the cost of the operation was about equal to the cost of its construction.
Dismantling a commercial plant may cost anywhere from $31 million to more than $100 million in 1977 dollarsbetween three and ten percent of the $1 billion capital cost, predicts a recent U.S. Congress report, Nuclear Power Costs. Those figures do not include the perpetual care costs for tending the rubble from the plant which contains radioactive nickle that may remain hazardous for up to 1.5 million years.
Reactors are dismantled in three stages: mothballing, entombment and complete removala process that for a large reactor may take anything from fifty to a hundred years. Only five prototype plants have gone beyond the mothballing stage, at which the plant is kept intact but the reactor is sealed off with anti-contamination barriers. In the second and third stage, reports The Economist (May 6th, 1978) 'workers will need to remove from a typical magnox reactor radioactive parts consisting of 2,500 tonnes of mild steel, 100 tonnes of stainless steel, and 2,500 tonnes of graphite. The inner layer of the concrete shield around the plant will also be radioactive to a depth of 1.5 metres. All this must be dismantled, shipped and stored.' It may well be that the US government merely intends to 'mothball' all reactors. If so, the American landscape will some day be dotted with monuments, even entire zones, requiring perpetual surveillance. Although an EEC committee is looking into the problem, nobody yet knows how a reactor will be dismantled in the case of an emergency.
The Disposal Dilemma
For the ordinary citizen, caught up in the waste disposal controversy, separating myth from reality is extremely difficult. The government persists in asserting that a solution is in hand and simply needs some hard decisions and hard money to be implemented. Yet one need only refer to some of the government's own studies to realize that what exists are not demonstrated technologies but merely concepts of waste handling, containment and burial. In fact the more research that is done into methods of waste disposal, the more scientists are realizing the extent of the gaps in their knowledge. A recent report, prepared by the Office of Science and Technology Policy, admits that 'the knowledge and technological base available today is not yet sufficient to permit complete confidence in the safety of any particular repository design or the suitability of any particular site.'
No commercial waste has yet been solidified in the U.S. and although some fission products have been solidified into glass blocks in France, it has since been revealed that they have already begun to leach. Not surprisingly vitrification has come under attack; 'In the opinion of the materials community, glass is relatively unstable and thermodynamically badin short it "chews up" easily', says Rustum Roy, Director of the US National Academy of Science's Committee on Radioactive Waste Management, whose highly critical report was published in August.
As yet no satisfactory terminal geological repository has been located. Indeed the deadline set by the government for deep-earth isolation has already been postponed until the early 1990s, and many believe that it will be further postponed until the beginning of the next century. The government's main disposal strategy at present is a rather pathetic plan to construct two Away-From-Reactor (AFR) siteseffectively oversize ponds in which spent fuel elements can be temporarily stored. Without these AFRs the nation's reactors, already rapidly exhausting their own fuel ponds, will soon have to shut down.
In fact, the AFR policy is merely a return to an earlier, discredited concept of waste disposal known as Retrievable Surface Storage (RSS) which was intended to keep spent fuel within easy reach for eventual reprocessing. At the time the RSS method was severely criticized by many Federal Agencies which feared that it could well become a permanent solution. Those fears are now confirmed; with permanent burial a distant chimera, the RSS, in the guise of AFRs, will be the sole means of waste disposal for the foreseeable futurea series of high-level waste repositories above ground, but without the multiple barriers of geological sites to contain the radioactivity. Not surprisingly critics of nuclear power see the decision to opt for AFRs as an admission that a permanent solution is remote. Or is it a cynical and none too subtle move not to solve or even ease the waste problem, but to prop up a failing industry?
In a desperate attempt to calm public fears by digging a hole in the ground and getting some waste in there fast to demonstrate a 'solution', a plan for a terminal repositorythe Waste Isolation Pilot Project (WIPP)is being pushed through in New Mexico. At first the State (whose largest employers are the Los Alamos weapons laboratory and the Sandia Laboratory) welcomed the project but withdrew their support when they discovered that they would receive not only low- and high-level military wastes but high-level commercial wastes and 1,000 spent fuel assemblies as well. Even formerly enthusiastic officials are now balking at the idea and one of them has introduced legislation in Congress designed to give states the right of veto over waste repositories. Many other Senators would also like to give their states guaranteed right of veto on which the government could never renege. But whilst the DOE claims that it will honor any state refusal to accept waste, it clearly could not tolerate such refusals from all fifty states. Understandably, Secretary of Energy James Schlesinger is not keen to give the states a statutory right of veto: 'I think the matter would be best left unresolved,' he told a House Committee on Internal Affairs. 'It is a grey area of the law and I think that it is more convenient to leave it there rather than trying to define it too precisely.'
Many of the government's efforts at deep-earth burial have gone into the exploration of salt formations, primarily in New Mexico, Louisiana, New York, Ohio and Michigan. Salt was generally viewed as the most promising of all geological media, mainly because of its plasticity which, it was believed, could help seal the repository. As recently as 1976, officials from the Energy Research and Development Administration (ERDAnow the Department of Energy) were predicting confidently that burial in salt would require 'only straightforward technological and engineering development'. Now, however, salt is seen to have major drawbacks, all of which have been minimized by the industry: it is highly corrosive, not entirely free of water as had been assumed, and is usually located in areas of oil, gas and potash which could mean that there are uncharted drilling holes that would weaken the integrity of the salt formation. (Precisely that happened at Lyons, Kansas, where the Oak Ridge National Laboratory was storing spent fuel in 1965. In 1970, the government announced that Lyons would be the first Federal waste repository, but over the next few years old oil and gas holes were discovered near the site and the plans were abandoned).
The use of salt deposits has come in for strong criticism from both the Office of Science and Technology Policy (OSTP) and the U.S. Geological survey (USGS). The OSTP report that whilst salt is the best understood of all geological media and 'with conservative engineering' might be an acceptable repository, it has unique problems: 'Because of salt's highly corrosive nature, currently planned waste containers would seem to be breached and substantially corroded by all but the very driest salt within months to years.' They add that salt is soluble and 'does not provide the absorptive qualities of other rocks nor is it benign to interactions with the waste and container'. These, it states, could prove 'troublesome' in the event of a canister breaking. The OSTP also stresses the great gaps in technical knowledge of waste disposal.
The same point is taken up in the USGS's recent circular on geological disposal: 'Many of the interactions (between waste, canister and geological medium) are not well understood, and this lack of understanding contributes considerable uncertainty to evaluations of the risks of geological disposal of high-level waste.' The circular also pinpoints three major problems that are likely to occur in salt formations: disturbance of the medium caused by the actual mining; chemical disturbances created by introducing new fluids not in chemical equilibrium with the salt; thermal disturbances from hot wastes that will in turn compound the two other problems. It also expresses concern for unknown geological faults, ground water conduits and abandoned excavationsall of which could allow water into the repository. In addition, hot canisters tend to attract brine towards them.
Salt was not the only geological medium the USGS was worried about; in rock deposits chemical change due to the introduced thermal energy, could lead to thermal expansion and contraction that would fracture the canisters. This thermal energy could also break down hydrated minerals and form new ones, with significant increases in the permeability of the rock. 'Given the current state of our knowledge,' warns the USGS, 'the uncertainties associated with hot wastes that interact chemically and mechanically with the rock and fluid system appear very high.'
In June a brutally honest report from the US Environmental Protection Agency gave what may be the death blow to the use of salt for disposal. This report explodes the common belief that many salts do not contain water; close inspection of even the driest salts reveals 'significant amounts of water in fluid inclusions and intergranular boundaries.' The waste canisters are 'likely to be bathed in water soon after emplacement' and, worse still, the moisture will actually cause the crystals to burst at temperatures half that of the canister. As for the canister itself, the report states that 'no tests have shown that any of the candidate metals will resist corrosion by the salt solutions that are likely to be at the canister surface for a significantly long time. Under these circumstances it is likely that the canister could be breached within time scales of a decade or less.'
Neither the government nor the nuclear industry will countenance discussion of a nuclear moratorium until waste isolation technology has been demonstrated, nor will they admit that continued production of wastes could conceivably make the situation worse. They respond that even if the industry shuts down, we will still have large amounts of waste to deal with. This is an argument which totally misses the point; not only is it easier to deal with a fixed quantity of wastes than with a quantity ten times as large; but also there may be very fewperhaps only onegeologically acceptable burial sites in the US. Only a limited amount of waste could then be accommodated, and continued production will require additional burial sites that may be totally unsatisfactory.
The key questions are: how much is the problem compounded by not stopping waste production? How many tons of uranium tailings will blow in the wind? How many more thousands of annual truck and rail shipments of uranium and spent fuel will be needed? How many more derailment accidents will there be? How many additional AFRs must be built? And how many permanent burial sites?
If after twenty years of nuclear power no single example of effective containment has been demonstrated, what hope is there of future success? Can there possibly be any justification for allowing the nuclear industry to go on manufacturing waste products whose potential for destruction neither scientists nor government can begin to calculate? Can it be permitted to prop itself up with the myth rather than the reality of safe waste disposal?
- Radioactive Wastes at the Hanford Reservation: A Technical Review (National Research Council - National Academy of Sciences, 1978)
- Geological Disposal of High-Level Radioactive Wastes: Earth Science Perspectives. (US Geological Survey Circular 779)
- Nuclear Energy's Dilemma: Disposing of Hazardous Radioactive Wastes Safely. (Controller General report to Congress 9/9/77)
- Alternative Processes for Managing Existing Commercial High-Level Radioactive Wastes (NUREG-0043, Nuclear Regulatory Commission. April 1976, by Battelle Pacific NorthWest Laboratory)
- Status of Nuclear Fuel Reprocessing, Spent Fuel Storage and High-Level Waste Disposal (California Energy Resources Conservation and Development Commission, 1978)
- Report of the Task Force for Review of Nuclear Waste Management. (US Dept. of Energy, February 1978)
Source: New Ecologist, Number 6, Nov/Dec 1978.