Issues in recent court cases; Treatment of risk and nuclear safety

Takada, Tsuyoshi  ; Horiike, Hiroshi*; Miyano, Hiroshi*; Ebisawa, Katsumi*

Trials related to seismic safety of nuclear power plants are being held in many places in Japan. Among many controversial issues, the study group on trials on nuclear power plants in JSM has studied the recent court decisions on nuclear safety against future earthquakes; that of the Osaka District Court, the Mito District Court, and the Sendai District Court. The concept of "substantial safety" and "procedural safety", along with the concept of "Defense in Depth (DiD)" proposed by International Atomic Energy Agency (IAEA), particularly the fifth protection level namely effective evacuation planning are discussed herein. Finally, the probabilistic risk assessment (PRA) study must be done to treat the substantial safety of nuclear power plants and to cover all levels of protection described in the DiD concept.