Congressional Record, Volume 134, Number 91, June 20, 1988

United States of America Congressional Record PROCEEDINGS AND DEBATES OF THE 100th CONGRESS, SECOND SESSION Washington, Monday, June 20, 1988 No 91 Senate SUBSEABED DISPOSAL OF NUCLEAR WASTE Mr. HECHT. Mr. President, last fall I spoke on the floor of the Senate about the need to resume United States participation in the international research on the possibility of sub-seabed disposal of nuclear waste. As a result of my efforts, and with the cooperation of several key Members of this body and the House of Representatives, there is now a special Office of Subseabed Disposal Research within the Department of Energy. Within a matter of a few weeks, at most, I expect to see the Woods Hole Oceanographic Institution delegated the responsibility to assemble a university-based subseabed consortium to plan and conduct this research. I have made no secret of my opposition to a deep geologic repository for high level nuclear waste at Yucca Mountain, NV, or anywhere else. Deep geologic disposal of unreprocessed spent nuclear fuel will be dreadfully expensive, in excess of $25 billion, and has never been proven safe anywhere in the world. I favor reprocessing and recycling nuclear waste so it can be burned for energy. At present, America's nuclear waste management strategy entirely depends on siting a repository at Yucca Mountain, NV. However, I am continually hearing report after report about how many problems there are with both the Yucca Mountain site, and the way the program is being run. If the technical problems turn out to be as serious as certain people think they are, or if the program suffers from proce-dureal inadequacies and quality control problems, then it is very much an open question in my mind as to whether the Nuclear Regulatory Commission will ever grant a license for a repository at Yucca Mountain. If Yucca Mountain is unlicensable, then dozens of nuclear powerplants all around the country may have to be shutdown, because they operate under State laws that allow them to operate only so long as the Nuclear Regulatory Commission has confidence that there is a solution to the nuclear waste management problem. If Yucca Mountain turns out to be no good, then there is no monitored retrievable storage facility, and there is no waste confidence. Mr. President, there are tens of millions of people in the eastern States who depend on nuclear power to run their factories and light their homes. I have no desire to see these people suddenly jobless in the dark because the Congress put all its nuclear waste eggs in a poorly conceived Yucca Mountain basket. I would think that even those here in the Senate, or the other body, who really think that Yucca Mountain is the answer to their own parochial nuclear waste problem, would see the value in taking out a little inexpensive public policy insurance. Without this insurance, known as continuing research on subseabed disposal, a number c^ people on Capitol Hill might just wake up one morning in about 10 years and discover that their State is being considered once again for a repository. If we continue research on sub-seabed disposal, then the factories can stay open, the lights can stay on, even if the Nuclear Regulatory Commission turns down a Yucca Mountain repository. As I stated during the nuclear waste debates last year, other countries have in fact borne the brunt of the cost of international subseabed research efforts. Other countries are very actively and aggressively pursuing any of several variations on the theme of disposing of nuclear waste under the seabed. Sweden has a facility mined under the sea near its coast where it stores low and medium level nuclear waste. There is active discussion in Great Britain about a similar concept which may soon be applied in that country. Earlier this year, the Washington Post reported how the chemistry of seawater might be used to dramatically improve our ability to isolate high level nuclear waste from the human environment, particularly if that waste is reprocessed first. In a waste management system involving reprocessing, the only sensible thing to do with any residual liquid waste is to vitrify it. Vitrification is a very effective way of keeping the waste from dissolving away into the ground water when the waste canister eventually corrodes. It turns out that the magnesium found naturally occurring in sea-water dramatically slows down the rate at which the vitrified waste dissolves. In other words, if you want to keep the waste out of the human environment, the best place for it is somewhere it will be in contact with sea water-saturated rock or sediment before it gets a chance to leak out into the environment more generally. If we proceed with a land-based repository, then we would need to put magnesium salts into the dry holes where the waste canisters would be located, to try to imitate conditions that are found underneath the seabed. Rather than trying to mimic the ocean, I would hope it would be obvious to everyone that it makes more sense to take a closer look at the ocean itself. Mr. President, I hope that Senators from States whose citizens rely on nuclear energy for their jobs and domestic energy needs, and Senators from States which may once again be considered for a land-based repository when the Yucca Mountain, NV, site turns out to be unacceptable, will support my efforts to get America once again to meaningfully participate in the cooperative international research effort on the subseabed disposal of nuclear waste. Mr. President, I ask that an article on subseabed disposal by Dr. Tulenko of the University of Florida, an article on subseabed work in Great Britain from New Scientist magazine, and the Washington Post article on the beneficial effects of magnesium found in sea-water in enhancing our ability to isolate nuclear waste from the human environment, be printed in the Record. The material follows: [From the Washington Post, Jan. 18,1988] Discovery Could Reduce Risks of Radioactive Waste Storage One of the risks of long-term storage of highly radioactive nuclear wastes could be reduced by a factor of 100 or more if the storage facility imitated the ocean chemically, a team of government and private researchers said last week. Their discovery, which has been tested only in the laboratory, would be a modification of a storage method now used in France and Belgium, but only under consideration for the United Stales and other nuclear-powered countries. The current method involves mixing the sludgelike wastes, partly dissolved in acid, with melted glass and then pouring the mixture into stainless steel canisters. After the glass cools and hardens, the sealed canisters would be buried. The steel is expected to resist corrosion for about 300 years. After that, however, it would be possible for ground water to reach the glass and slowly corrode it, releasing radioactive matter into the water table. The modification "will prevent the glass for corroding for at least 25,000 years," according to Sidney Alterescu of NASA's God-dard Space Flight Center in Greenbelt. The idea emerged from the work of John A. O'Keefe, a Goddard geophysicist who studies tektites, hardened droplets of natural glass formed when meteorites land with enough force to melt and splash rock. O'Keefe and his colleagues have found that tektites recovered from the ocean where some fell millions of years ago, are far less corroded than those of comparable age found on land. Experiments by Aaron Barkatt of the Catholic University of America have established that sea water's dissolved magnesium makes the difference. The magnesium-rich water forms a protective coating on the glass. One way to use the discovery, the scientists suggest, would be to mix nontoxic magnesium compounds, such as Epson salts, into the earth around the canisters. When the groundwater breaches the canisters, it will resemble the ocean chemically and coat the glass. Disposal of Waste; A Status Report (Session Organizer: J.S. Tulenko (Univ. of Florida) 1. Radiological Assessment of the Consequences of the Disposal of High-Level Radioactive Waste in Subseabed Sediments, G. de Marsily (Paris Sch of Mines-France), V. Behrendt, D.A. Ensminger, C. Flebus, B.L. Hutchinson, P. Kane. A Karpf, R.D. Klett, S. Mobbs, M. Poulin, D.A. Stanr ?rs. D. Wuschke, invited. introduction The radiological assessment of the seabed option consists in estimating the detriment to man and to the environment that could result from the disposal of high-level waste (HLW) within the seabed sediments in deep oceans. The assessment is made for the high-level waste (vitrified glass) produced by the reprocessing of 10* tons of heavy metal from spent fuel, which represents the amount of waste generated by 3333 reactor-yr of 900-MW(electric) reactors, i.e., 3000 GW (electric) yr. The disposal option considered is to use 14667 steel penetrators, each of them containing five canisters of HLW glass (0.15 m? each). These penetrators would reach a depth of 50 m in the sediments and would be placed at an average distance of 180 m from each other, requiring a disposal area on the order of 22 x 22 km. Two such potential disposal areas in the Atlantic Ocean were studied, Great Meteor East (GME) and South Nares Abyssal Plains (SNAP). A special ship design is proposed to minimize transportation accidents. Approximately 100 shipments would be necessary to dispose of the proposed amount of waste. methodology The assessment was done within the framework of the International Seabed Working Group of the Nuclear Energy Agency of the Organization for Economic Cooperation and Development, using the best models and data available at the end of 1986 (Ref. 1). Three types of calculations are made: 1. The base case, or "normal" scenario: the waste is assumed buried at its prescribed depth and all the barriers believe as anticipated. 2. Several "abnormal" scenarios, where one or more components of the system behave abnormally. 3. Scenarios of transportation accidents, occurring in coastal areas or in the deep seas: not only the consequences of such accidents are analyzed, but also their probability of occurrence is assessed given a special ship design. Probability of recovery actions is also studied. The assessments are made with both a deterministic and a stochastic methodology. This makes it possible to estimate not only the most likely doses resulting from each scenario, but also the range of uncertainty of this estimation, given the uncertainty in the available data. results No significant differences were found between the two sites (GM? and SNAP), although the quality of their sediments is slightly different. We will therefore not specify the site origin of the results. BASE CASE For the base case, the peak dose to the maximally exposed group of individuals is on the order of 2.8 x 10"* Sv.yr-1 for the complete repository of 10s tonne heavy metal (HM), occurring 150000 yr after disposal. This is ~3.6x 10s times smaller than the International Commission on Radiological Protection recommended limit (10"*5v.yr_I), and also 3.6x10* times smaller than background doses: such very small doses are therefore totally negligible and insignificant. The uncertainty on this value calculated by the stochastic analysis ranges between 3x10"16 and 3x10"' Sv.yr"1, and the highest dose ever calculated In the stochastic analysis is 2.5x10"* Sv.yr-1 in a sample of 500 runs. The radionuclides contributing most to these doses are the long-lived poorly sorbed fission products (?eTc, 7flSe, ??Sn, ?"I, 136Cs), and the major pathway is the consumption of mollusks, crustaceans, seaweed, and fish. The collective doses integrated to 10* yr is on the order of 2.2x10* person-Sv and to 10T yr of 2.8 xlO4 person-Sv. These figures can only be used for comparative purposes with other disposal options. abnormal scenarios For the various abnormal scenarios, it was found that the seabed option was extremely insensitive to a large number of assumptions or behaviors of the components of the system. In particular, for a properly em-placed penetrator, the corrosion and leaching properties of the waste are not significant. Only three scenarios were found to increase the doses significantly (factor of individual dose increase compared to the base case): 1. Emplacement of penetrators at a depth <10 m in the sediment (factor of 100 and higher). 2. Existence of an upward pore water velocity in the sediments: the base case scenario assumes, as presently observed, that no pore water velocity exists in the sediments above the detection limit, which is 10"* m.yr"1; causes of such movements of water could be compaction, natural convec- tive cells developing between the crustal bedrock and the ocean bottom, or other unknown mechansims (factors up to 10?). 3. Change in the retention properties of the sediments for the radionuclides (factor of 170). transportation accidents It was found that the doses arising from transportion accidents could be very severe, especially for accidents in coastal waters (in the order of 6.5x10"' Sv.yr"1 per metric tonne of heavy metal of waste lost In the sea, with an uncertainty range of 3.7x10"* to 1.1x10"* Sv.yr-1 tonne"1). However, it 1s possible to design a transportation vessel and organize recovery actions, so that the probability' of occurrence of such doses is extremely small and in practice, negligible. In none of the above scenarios does the dose to fauna appear to be significant. discussion The results of this radiological assessment seem to show that the disposal of HLW In subseabed sediments is radiologically a very acceptable option. This statement holds true as far as the assumptions, models, and data used in the calculations can be validated. A further research program on sub-seabed disposal should therefore aim at achieving such a validation. This task must be completed before the feasibility study of the subseabed option can be considered complete, along with other tasks that remain to be done (e.g., further site selection, engineering design and testing, etc.). Since, in many cases, conservative assumptions or data were used in this assessment, it is most likely that future research will show that the consequences of this disposal option may be even smaller thar. those described here. nuclear waste goes to sea Finding acceptable land-based sites for dumping radioactive waste is a headache for both the nuclear Industry and the British government. Underground burial, the strategy largely favoured by the agency responsible, the Nuclear Industry Radioactive Waste Executive (NIREX) is a very unwelcome prospect for those who may end up living close to the sites. Over the next 40 years, a final resting place must be found for nearly 1.2 million cubic metres of rubbish from nuclear power plants, nuclear reprocessing and a variety of research, medical, industrial and military sources. That is the estimated total of low-and intermediate-level waste (ilw and llw) which will be generated. Now, two British companies have produced competing solutions which sidestep the problem of winning approval for burial on land. Both proposals involve disposal under the seabed. And both methods rely heavily on conventional mining and offshore oil and gas technology. The rival companies are Wheeler Offshore and Consolidated Environment Technologies (CET). Wheeler's system is known as POWER, for Pipeline Operated Nuclear Waste Repository. Under this scheme can-nisters of radioactive waste would be "pumped" hydraulically down pipelines and placed, by remote control, in subsea wells. The waste would be loaded into the system at a shore station, possibly sited at a nuclear power plant. The canisters, up to 1.4 metres In diameter, would end up in wells 1,700 metres below the sea. Wheeler estimates that one of its repositories could hold as much as 50,000 cubic metres of packaged waste. CET's concept is on a much larger scale. It would involve sinking a shaft 15 metres in diameter under the seabed. Large modules of waste, up to 2,000 tonnes in weight could be lowered into the shaft. This could be sunk up to 3.000 met res deep. Th<> scheme would be suitable for bulky waste from decommissioned power plants and mothballed nuclear submarines. It would also cut down the radiation dose experienced by workers who would have to handle large volumes of waste. To date Wheeler has spent more than ?200.000 on developing their scheme. CET has spent just over ?120,000. Both systems require at least three or four years' development work before their commercial viability can be assessed. Wheeler has joined forces with a French company called ACB Alsthom. Together they are bidding to install a POWER system in Taiwan. The Soviet Union is also interested. CET says that the Japanese are interested in its system, but so far neither proposal has won the backing of NIREX. Pull-scale technical presentations of both schemes are due to be made to NIREX over the next 10 days. Both face formidable legal obstacles, as well as considerable political, public and diplomatic opposition to the use of the sea, and the seabed, for radioactive waste disposal.