Design Concepts for Passive Heat Rejection in CANDU Reactors

Abstract

A study has steed at AECL to assess the safety and capital cost implications of a more extensive use of passive safety design features in CANDU reactors. The passive designs avoid reliance on electrical power and on operator action for three days following an accident. A further goal is to minimize periodic testing by designing systems that function during normal operation, and therefore continually demonstrate their availability. At this stage, a number of concepts have been identified for passive heat removal and some preliminary sizing has been completed based on a CANDU 6 reactor design. The paper describes the more attractive concepts and the results of preliminary performance assessments. The next step in the study is to prepare cost and safety assessments. The latter will include an estimate of the improvement in core melt frequency. A positive assessment would lead to a more detailed design study.