Thermal-hydraulic analysis of small break local for indian phwrs with relap-cobra

摘要

Small Break Loss of Coolant Accident (SBLOCA) Analysis has been carried out for the break at Reactor Inlet Feeder (RIF) for 220 MWe Indian PHWRs. A break size of 0.25percent has been selected for the study which cause a low flow situation in the reactor channel associated witht he brocken feeder along with delayed reactr trip. The study involves a global simulation of the reactor with a break with the safety analysis code RELAP4/MOD6 followed by the affected reactor channel analysis with subchannel analysis code COBRA IV-I. The reactor channel end boundary conditions botained from the RELAP4/MOD6 simulation has been used in the transient module of COBRA IV-I. The transient thermal-hydraulic parameters during LOCA and the effect of the subchannel flows on the clad surface temperatures are discussed in the paper.