Loss of External Load Analysis with RELAP5/MOD3.3 Patch 03 Code

摘要

By removing resistance temperature detectors (RTD) bypass manifold system with fast-response thermowell-mounted RTDs the reactor coolant system temperature measurement time may change, what influences the time delays for overtemperature DeltaT (OTDeltaT) and overpower DeltaT (OPDeltaT) trips. The total time delays should not exceed the value assumed in the accident analyses. In this paper we are presenting Krsko nuclear power plant specific analysis of loss of external load varying the total delay time for OTDeltaT trip. For simulations the latest RELAP5/MOD3.3 Patch 03 thermal hydraulic computer code was used. The verified standard RELAP5/MOD3.3 input model from 2008 (cycle 23) was delivered by Krko nuclear power plant. Base case calculation was compared to safety analysis report calculation to qualify the RELAP5 calculated results before the sensitivity analyses were performed.