Taipower's Transient Analysis Methodology for Pressurized Water Reactors

Abstract

The methodology presented in this paper is a part of the Taipower's Reload Design and Transient Analysis Methodologies for Light Water Reactors developed by the Taiwan Power Company (TPC) and the Institute of Nuclear Energy Research. This methodology utilizes four computer codes developed or sponsored by Electric Power Research Institute: system transient analysis code RETRAN-02, core thermal-hydraulic analysis code COBRAIIIC, three-dimensional spatial kinetics code ARROTTA, and fuel rod evaluation code FREY. Each of the computer codes was extensively validated. Analysis methods and modeling techniques were conservatively established for each application using a systematic evaluation with the assistance of sensitivity studies. The qualification results and analysis methods were documented in detail in TPC topical reports. The topical reports for COBRAIIIC, ARROTTA, and FREY have been reviewed and approved by the Atomic Energy Council (AEC). TPC's in-house transient analysis methodology have been successfully applied to provide valuable support for many operational issues and plant improvements for TPC's Maanshan Units 1 and 2. Major applications include the removal of the resistance temperature detector bypass system, the relaxation of the hot full-power moderator temperature coefficient design criteria imposed by the ROCAEC due to a concern on Anticipated Transients Without Scram, the reduction of boron injection tank concentration and the elimination of the heat tracing, and the reduction of reactor coolant system flow.