Calculation of Hydraulic Transients in SRP Reactors by the GRASS Code

摘要

Four types of postulated hydraulic transients were calculated for Savannah River Plant (SRP) reactors. The GRASS computer code was used, which calculates a three-dimensional reactor model with fully coupled neutronics and engineering feedback. The four types of transients calculated were: (1) a primary coolant pump shaft break, (2) loss of ac power to primary coolant pumps, (3) loss of power to secondary coolant pumps, and (4) closure of main coolant isolation valves. Nine cases of the four types of transients were calculated; calculations were continued beyond primary scram action until the backup shutdown system acted. The serices of GRASS calculations verified that the safety systems would terminate the transients before any steaming or assmbly damage occurred, indicate good agreement between calculated and experimentally measured flow in all cases where data were available, and verified analyses of some cases that were previously calculated by simpler codes. (ERA citation 06:010932)