SIMBRASS and Neutron Overpower Analysis

Abstract

CANDU reactors are equipped with two independent Shutdown Systems (SDSs) which may be initiated through a variety of measures. One of the principal means is the Neutron Overpower Protective System (NOP) which provides a direct measurement of the neutron flux throughout the reactor core. SIMBRASS is the Nuclear Safety Analysis code which has been used to establish the NOP trip setpoints implemented at Ontario Hydro, Ontario Power Generation (OPG) and Bruce Power nuclear stations for over 20 years. This paper describes the SIMBRASS code, its applications, and some of the capabilities of the newly developed code version, SIMBRASS 5.0.