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Kakehi, Isao; Nakabayashi, Hiroki
JNC TN9400 2000-051, 237 Pages, 2000/04
In this study, we have proposed the concept of safety systems (solutions of safety problems) in pyrochemical reprocessing systems (lt consists of pyrochemical reprocessing methods and the injection casting process for the metal fuel fabrication, or vibro-packing process for the oxide fuel fabrication.) which has different concept from the existing PUREX reprocessing method and pellet fuel fabrication process. And we performed its safety evaluations. FoIlowing the present Japanese safety regulations for reprocessing facilities, we pointed out functions, design requirements and equipments relating to its safety systems and picked up subjects. For the survey of safety evaluations, we first selected anticipated events and accident events, and second by evaluated 6the correspondence of the limitation of the public exposure to the accidents above, by using two parameters, the safety design parameter (the filter performance to confine radioactive matelials) and the leak inventory of radioactivities, and last by picked up its problems. ln addition to the above evaluations we performed basic criticality analyses for its systems to utilize these results for the design and evaluation of the criticality safety management system. Thus this study specified the concept of safety systems for pyrochemical reprocessing processes and then issues in order to establish safety design policies (matters which must consider for the safety design) and guides and to advance more definite safety design.
*; *; Tanai, Kenji
JNC TN8400 99-050, 94 Pages, 1999/11
This paper reports on the evaluations of operational activities for a High Level Radioactive Wastes Disposal Facility, from initial acceptance of vitrified waste at a surface facility to emplacement engineered barriers in underground facilities. The purpose of this analysis is to confirm the technical feasibility of geological disposal. First, the basic design and repository system requirements are identified. Second, operational activities in surface facilities, access facilities and underground facilities are described. The required procedures and equipment, suitable for specific emplacement concepts and configurations for engineered barrier systems are discussed for specific examples. Countermeasures for potential adverse events or conditions are based on extensive civil engineering and mining experiences in Japan and abroad. The time schedule is also evaluated on the basis of these concepts. In addition, the concept of stationary and mobile radiation control areas is studied based on experiences and practice in current nuclear facilities. Finally future research and development items are summarized.