COMPARISON OF PREDICTIONS FROM THE REACTOR PRIMARY SYSTEM DECOMPRESSION CODE (RELAP3) WITH DECOMPRESSION DATA FROM THE SEMISCALE BLOWDOWN AND EMERGENCY CORE COOLING (ECC) PROJECT

摘要

RELAP3, a computer code developed for predicting the thermal-hydraulic response of pressurized-water nuclear reactor systems to a loss-of-coolant accident (LOCA), was partially evaluated by comparing RELAP3-predicted transient pressures and residual water with experimental data from the Semi-scale Blowdown and Emergency Core Cooling (ECC) Project. The blowdown tests were conducted in a 6 ft3 cylindrical vessel having a height of approximately 5.3 feet and an inside diameter of approximately 1„2 feet. Initial test pressures and temperatures were about 2350 psia and 540°F.nRELAP3 predicted the pressure behavior as a function of time within a maximum deviation ±100 psi of the experimentally measured pressure data;agreement was generally much better. Agreement between analytical and experimental results depended on the value of discharge coefficient selected in the analysis. A discharge coefficient of 0.6 gave best agreement with experi-mental data for the 100% breaks (100% break of four-inch İD pipe) whereas a value of 0.8 gave the best agreement for the 2% breaks.nThe residual water in the semiscale vessel was predicted within a maximum deviation of ±20% of the measured residual water.