CYCLE SPECIFIC BWR RELOAD ANALYSIS USING SIMULATE-3K

Several organizations, utilities, fuel suppliers and code developers are performing cycle-specific transient predictions for BWRs. The accuracy of the prediction depends on code approximations and code-specific validation results. The penalty that has to be taken in safety analysis depends on the extent and success of the validation method. This paper presents applications of SIMULATE-3K (S3K) to operational transient calculations and results of validation efforts in the Finnish Olkiluoto 1 and 2 plants. The validation models actual events that have occurred at Olkiluoto and includes a fast pressurization and a fast flow reduction that are typical of internal-pump BWRs. Furthermore, the paper discusses the capability that offers S3K to evaluate Operating Limit Minimum CPR (OLMCPR) directly based on 3D transient methods, without the approximations used in traditional