Application of STREAM/RAST-K 2.0 Toward Nuclear Design Report Generation

Abstract

STREAM/RAST-K 2.0 is a two-step approach nuclear reactor analysis code system for the design and analysis of Light Water Reactors (LWRs) that is currently under development by the Computational Reactor Physics & Experiment Lab (CORE) research group at the Ulsan National Institute of Science and Technology (UNIST). RAST-K 2.0 is a nodal diffusion reactor core analysis code for Pressurized Water Reactor (PWR) analysis. It can be used for steady-state and transient analysis of the reactor core, in-core fuel management, core design calculations, and load follow simulations. The lattice physics code, STREAM, solves the transport equation to generate the few-group constants (i.e.,2-group cross section and group constant data) of the fuel assemblies and reflector models which is to be used in RAST-K 2.0. The STN files, containing the cross section and group constant data (output of STREAM), is collected by STORA and then combined and reformatted for use in RAST-K 2.0. The current study aims to apply the STREAM/RAST-K 2.0 code system to reproduce all the data contained in the existing Nuclear Design Report (NDR) for Shin-Kori Unit 1 Cycle 1. Shin-Kori Unit 1 is a PWR with thermal core power of 2,815 MWth. It is designed to provide 13,800 MWD/MTU of energy extraction during Cycle 1. The NDR, compiled by Kepco Nuclear Fuel Co., Ltd. (KNF), describes the nuclear characteristics of the reactor core with respect to core components, depletion characteristics, operational capabilities, reactivity parameters, and reactivity control. Attempting to recreate all this data with the STREAM/RAST-K 2.0 code system provides a good opportunity to test the accuracy, capabilities, and user friendliness of the code system. The current STREAM/RAST-K 2.0 code system is capable of performing most of the data analysis contained in the NDR. During this study, the shortcomings of the code can be identified, so that the additional required capabilities may be incorporated. Furthermore, in the current version of the code system, some of the data (such as the temperature coefficients, temperature defects, and highest worth rod) can be calculated manually. For commercial application, it is preferred that such functions be automated. The results of this study will thus help to demonstrate the accuracy and improve the quality of the STREAM/RAST-K 2.0 code system.