A review of neutronics and thermal hydraulics coupled codes SAC-RIT and RITAC

Safety analysis of a research reactor includes simulations of reactivity initiated accident (RIA), loss of coolant accident (LOCA) etc. For design and licensing of research reactors, computer codes with capability of analyzing those transients are needed. Many codes such as RELAP, RETRAN and ATHLET have been developed and widely used for safety analysis of power reactors operating under high temperature and high pressure conditions. Two computer codes namely SAC-RIT (Safety Analysis code for Reactivity Initiated transient) and RITAC (Reactivity Initiated Transients Analysis Code) based on coupling of point kinetics model with thermal-hydraulics model have been developed to analyze reactivity initiated transients related with upcoming projects like 2 MW Upgraded Apsara and 30 MW HFRR being designed at BARC. The codes have been developed to carry out reactivity initiated transient analysis for nuclear research reactors with plate/pin type fuel assemblies. This paper is aimed at presenting a review of the two codes. Both codes have been benchmarked against the transient analysis of 10 MW MTR (IAEA-BENCHMARK)