Disposal Container Safety Assessment - The Comprehensive Performance Evaluation of a 'Yoyushindo Disposal' Waste Container by Drop Test - 10087

To be prepared for decommissioning nuclear power plants, the Federation of Electric Power Companies of Japan has undertaken studies into "yoyushindo disposal," whose concept is similar to "intermediate disposal" called by international organizations, of higher-activity low-level radioactive waste. One of the studies is the development of a disposal container to store radioactive waste. To assess drop events of a waste package in the safety assessment of power plants and disposal facility, the drop resistance performance of the disposal container was evaluated by conducting a drop test using the three disposal containers in the actual dimensions, drop analysis under conservative conditions, and fracture mechanics assessment. The lids of the full-scale specimens for drop test were welded by automated remote control using a welding machine without pre- and post-weld heat treatment, simulating the situation of manufacturing an actual waste package. Results of the drop test showed that the disposal container underwent no penetration crack and splash of its content, under such conditions as the maximum weight and height expected in the handling. Drop analysis and the fracture mechanics assessment indicate that the strain of the disposal container caused by the drop impact does not exceed the fracture strain and unstable fracture does not occur. These tests and evaluation show that the disposal container is sufficiently drop-resistant under expected handling conditions.