Multibarrier effectiveness as the expedient measure for selecting the appropriate stabilization and immobilization procedure for the various waste categories

The management of radioactive wastes has become a major concern particularly with regard to the release of radioactive material to the environment and possible risks of contamination. The development of rational and acceptable options for radioactive waste disposal requires a clear understanding of radiators protection objectives and their application in planning, regulation and licensing. Considerable progress has been made over the past three decades within many countries utilising nuclear power to develop strategies for the management of nuclear wastes. All wastes should be managed in such a way that high standards of conditioning are maintained and that potential hazards originating from their disposal are reduced to levels that are as low as reasonable and well below admissible levels. However, deficiencies are evident in some areas of nuclear weapon fabrication. The nuclear fuel cycle is associated in the military weapon fabrication sector as well as in the civilian energy production field with two rather similar types of risk: 1. the risk due to the operation of the nuclear reactors and the appertaining fuel facilities, and 2. the risk contribution originating from the generation of radioactive wastes. The difference between these two categories of risk is that the first one has only a short time factor associated with it, since the lifetime of the plants is relatively short and drops to zero after plant shutdown. The second category is, more or less, a permanent kind of risk which will be inherited by future generations. Actual health effects of waste on people and populations, particularly over long periods of time, are not necessarily related to the level of radioactivity. If intensely radioactive waste is effectively isolated, then the radiation dose it causes can be much less than that accumulating from widely-dispersed but low-activity waste, particularly if this includes long-lived radioisotopes. By far the most important producers of nuclear wastes are nuclear power plants and their supporting fuel cycle facilities. Compared to nuclear power and reprocessing plants, only very small waste contributions come from research establishments, industry and medical applications. An additional source of radioactive waste arises from nuclear weapons production and related testing activities. The problems associated with disarmament requirements, however, are not dealt with in this paper. 10 refs