Aspects of criticality emergency planning;criticality excursion yields and criticality incident detection and alarm system reliabilities

摘要

A BNFL eview of two key aspects of Criticality Emergency Planning has led to the following conclusions; (a) that Ccriticality Emergency Planning should continue to be based on an excursion yield of 10~(18) fissions, (b) that the excursion yield used in safety cases for the omission of Criticality Incident and Detection alarm Systems (CIDAS) should continue to be 2x10~(19) fissions and (c) that the target for probability of failure on demand of CIDAS should now be set at 10~(-2).