Putting Radioactive Wastes on Ice

Abstract

The permanent disposal of high-level radioactive wastes accumulating from the growing production of nuclear energy is of vital concern to the international community and needs a worldwide commitment to a solution to this problem. As the number of nations who are turning to nuclear energy as a power source increases and as the world's fossil fuel resources are depleted, there will be greater dependence on nuclear energy and a greater accumulation of waste materials. Before the problem of high-level radioactive waste disposal evolves into a serious problem, all possible solutions should be investigated on a long-term basis, beginning immediately.Many waste disposal methods have been proposed and several are under investigation; however no permanent depository for these high-level radioactive wastes has been constructed in any country now accumulating the hazardous waste materials. Consideration must be given to the safety and world-wide environmental effects of the disposal method selected; thus as waste material buildup continues, the problem of its disposal assumes worldwide significance.Permanent disposal of the waste under the Antarctic ice cap would remove the wastes from populated areas and—if the depository were properly designed—would remove the wastes from all contact with the biosphere. The polar climate and the low temperature of the ice would furnish a sink for the heat given off by the radioactive waste canisters, and the large subsurface area of the ice would provide adequate space so that the canisters would not be in close contact with each other.All available evidence indicates that if the wastes were fused into a solid glass matrix, they could be practicably and safely transported to the interior of the ice cap. If placed on the surface of the ice, they would melt their own emplacement shafts which would rapidly reseat by freezing and plastic flow. The containers would sink slowly to the ice-rock interlace where they would remain safely isolated from the biosphere for more than 250,000 years. Scientific studies have indicated that the average temperature in Antarctica has remained below freezing for more than a million years so that the large thickness of polar ice may be expected to provide a good seal for at least a similar period into the future.Tentatively selected disposal sites are 600 to 1,000 kilometers inland from the nearest natural flora or fauna, isolated from the sea by mountain ranges as well as by long horizontal thicknesses of ice and frozen ground. The sites were selected to effectively eliminate the chance of any harmful effects due to ice movements.The Antarctic Treaty of 1959 prohibits radioactive waste disposal there, but it also provides specifically for amendments that are desired by the signatories, many of whom have or will have high-level waste disposal problems. This problem is one of truly international character, and Antarctica is the only “international” land territory which holds maximum promise of a practical and safe solution. Disposal under the Greenland ice cap, which is Danish territory, also appears to be possible from the technical viewpoint. This discussion however is concentrated on Antarctica because of its international accessibility. Similar technical considerations could be applied to the Greenland alternative.The major problems to be solved to establish the feasibility of this approach include complete literature and laboratory studies of the basic principles involved, followed by field surveys and experiments to achieve the following: (1) determine ice-canister interactions; (2) survey detailed ice thicknesses, movements and sub-ice topography; (3) determine temperature gradients down to the rock-ice interface; and (4) design, construct and field-test both engineering models and prototypes of an operating fail-safe transport and emplacement system.A brief comparison of the ice-cap approach with other methods which have been suggested for ultimate disposal indicates that it holds promise of being the most practical and safest solution. It thus deserves early and careful consideration by appropriate United States and international agencies. (Abstract presented at Symposium on Management of Radioactive Wastes from Fuel Reprocessing, sponsored by European Nuclear Energy Agency and IAEA, Nov. 27-Dec. 1, 1972, Paris, France.)