The role of safety analysis in addressing environmental qualification of the NRU reactor safety systems

Atomic Energy of Canada Ltd (AECL) National Research Universal (NRU) reactor located at the Chalk River Laboratories (CRL) was designed in the early 1950's and went critical in 1957. With a current rating of 135 MW thermal, this year marks 57th years of operation and the NRU still provides a neutron source for a wide range of experiments and for medical isotopes production. In NRU, equipment credited to support systems required for reactor shutdown, heat removal, containment, and monitoring following design basis events require environmental qualification (EQ). This paper describes the role of safety analysis to establish EQ requirements for the components of safety-related systems that either perform a safety function or whose failure may prevent a safety system from performing its function when subjected to postulated accident conditions. EQ of safety equipment results in benefits for the NRU reactor in terms of demonstrating the compliance with regulatory requirements for preserving the safety systems capability to perform their postulated safety-related functions before, during and following a Design Basis Accident (DBA). (author)