Analysis codes at EPRI

The Electric Power Research Institute (EPRI) has developed a Reactor Analysis Support Package (RASP) to provide utilities with computer programs and analysis guidelines for describing nuclear power plant behavior and performance. The objective of RASP is to provide an integrated, interlinked and validated code package, which includes analysis guidelines, that can be used by utilities for both fuel reload and plant safety analysis. RASP consolidates existing core physics, thermal-hydraulics and fuel performance computer codes into an integrated and self-consistent system. The RASP methodology consists of the following integral elements: individual computer codes, linkage and traceability software, analysis guidelines and utility seminars and workshops. The RETRAN system thermal-hydraulics computer code is used in this package to perform NSSS transient analyses. RETRAN has been used extensively to analyze both operational transients and small break loss-of-coolant accidents. RETRAN is applicable to both PWR and BWR plant transient analyses. The RETRAN nuclear kinetics models, which relate thermal-hydraulic changes to core power response (point or one-dimensional kinetics), require input from the physics codes via special RASP linkage codes and therefore truly demonstrate the need for a consistent, integrated physics and thermal-hydraulics package. The purpose of this paper is to give an overview of the RASP package with special emphasis on the NSSS transient analysis code RETRAN