Considerations in Implementing Earthquake Design Extension Condition (DEC)

Abstract

Lessons from the Fukushima accident have focused international attention on efforts in developing prevention and mitigation strategies for the accident scenarios beyond those design basis accidents (DBA) normally considered during the design of nuclear facilities. A subset of these beyond design basis accident (BDBA) scenarios are termed design extension conditions (DECs). The Canadian Nuclear Safety Commission (CNSC) is aligning with the international nuclear community especially IAEA to identify and adopt best practices as considerations regarding DECs. This paper provides an overview review of Canadian and international approaches being discussed to develop requirement for implementing DECs with regards to earthquake hazard and highlights key considerations that should be taken in implementing DECs to achieve plant safety with reasonable degree of confidence.