DEVELOPMENT OF A COUPLED CODE SYSTEM BASED ON SPACE SAFETY ANALYSIS CODE AND RAST-K THREE-DIMENSIONAL NEUTRONICS CODE

摘要

Recently, a new system thermal hydraulic analysis code named SPACE (Safety and Performance Analysis Code for Nuclear Power Plants) has been developed by the Korean nuclear industry. Similar to other system thermal hydraulic analysis codes, the SPACE code uses point kinetics for core power calculation. To model asymmetric core power distribution, 3-dimensional neutron kinetics calculation is required. A coupled code system of SPACE/RAST-K has been developed for simulation of interactions between a three-dimensional reactor core kinetics code, RAST-K and the system safety and performance analysis code, SPACE. The linkage is direct and explicit coupling of the two codes. The coupling provides a method of executing the RAST-K three-dimensional neutronics using the nuclear steam supply system boundary conditions, such as the core inlet temperatures, core inlet flow distribution, core outlet pressure, trip information and control rod movements, calculated by the SPACE thermal hydraulics code. The RAST-K calculates suitable core conditions based on the boundary conditions provided by the SPACE code. The results of the RAST-K code, such as the local power and reactivity, are transferred to the core heat structures of SPACE code. The soundness of the coupled code system is confirmed by simulating the main steam line break (MSLB) benchmark problem developed to verify the performance of a coupled kinetics and system transient codes by OECD/NEA. The calculation results show that the developed coupled code system works well as predicted.