Study on the structural integrity of overpacks

not registered; not registered; Kawahara, Kenichi*; not registered; not registered; not registered; not registered

In this study, a research and development plan for overpacks has been proposed by identifying issues for developing overpacks and organizing approaches for resolving them, as well as investigating a structural design methodology for overpacks and a quality control method in manufacturing them. The results are summarized as follows: (1)Technical Requirements for overpacks. Tentative technical requirements for overpacks are summarized on the survey of overseas literatures and performance assessment models discussed so far. (2)Determination of Reference Design. Handling and manufacturing methods for overpacks are discussed. Reference overpack structures are determined considering the discussion on the structural strength. (3)Approach to assuring structural integrity of overpacks. Load conditions and rupture modes after backfill are reviewed. A structural design methodology for overpacks was discussed based on FEM analyses. In addition, inspection items, which are necessary to assure that technical requirements are satisfied. (4)Destructive test. Destructive test is carried out in order to validate FEM analysis and others for basing a structural design methodology. As a consequence of the test, we could verify the sufficient reliability of FEM analysis and conservatism of the design methodology. (5)Quality control method. R&D items for quality control of overpacks are summarized based on the ideas of the order No. 73 issued by the Prime Minister's Office. Validation of measurement reliability for ultrasonic tests is the major R&D items in the future. (6)Preparation for R&D plan. A R&D plan for developing technical criteria for overpacks is summarized.