International Seminar on Final Disposal of Radioactive Waste
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to distinguish between disposal options. Various waste disposal approaches were explained. Characterization of Waste Products All countries have expanded efforts to produce a detailed characterization of the types of radioactive wastes. About 20papers in this category discussed different characteristics for multiple barrier systems. Volume reduction and solidification are used for most wastes. The spectrum of proposed and investigated conditioned waste forms for shallow-land burial and deep geologic disposal included as immobilization marices: bitumen, plastics, cement, glass, and synroc. Also considered was the suitability of solidified waste products for transportation, operation phase of the repository, and long-term disposal. Most emphasis was on the leaching resistance of the waste forms, but some reports dealt with the waste package behavior in mechanical and thermal impacts. The experimental results were mostly used for theoretical investigations to improve long-term predictions. This implies the need for investigations under site-specific conditions. To obtain comparable results for essential waste form characteristics, the investigation methods have to be standardized for both laboratory experiments and full-scale investigations. The methods for waste form characterizations and their suitability for predictions were discussed, as were solidification techniques. Waste Acceptance Requirements It seems that the waste package properties that are determined in the waste characterization can fulfill the waste acceptance requirements. The establishment of waste acceptance requirements is not well advanced in most countries, though, because the safe storage of waste packages is often the first priority. The various countries, of course, used
different approaches to define criteria for repositories and the performance of waste packages. Details of the criteria reached from the formulation of an overall criterion (e.g., the maximum permissible radiation exposure) to highly specific instructions on the performance of the repository and waste packages (which may over-fulfill the actual requirements). Waste acceptance requirements were generally developed from a specific analysis. The qualitative and quantitative requirements for the disposal of waste packages were presented for the Konrad iron ore mine (West Germany) and the WIPP facility (United States). Quality Control International agreement was found on the following aspects: • The waste producer/conditioner is responsible for the quality of waste packages. • The repository will control the fulfillment of the waste acceptance requirements. • The demonstration of waste package quality can preferably be performed by a qualification and instrumentation of a conditioning process with subsequent inspections. • Nondestructive tests on waste packages should be preferred over destructive tests. The concepts and methods for quality control of waste packages were elaborated; the waste producers used examples to show that it is possible to fulfill the demand of quality contro
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