Thermo-Hydraulic Analysis of Passive Heat Removal System (PHRS) in VVER-1000 Nuclear Reactor Using RELAP5 Code

The design and use of passive safety systems as one of the effective ways to increase reliability and safety level of nuclear power plants in new generation reactors has received much attention. In this paper, using RELAP5 computational code, the thermo-hydraulic analysis of the Passive Heat Removal System (PHRS) in the VVER-1000 reactor is investigated to ensure the capability of its performance under various conditions. For this purpose, the system nodalization is first extracted according to the available documentation and then the RELAP5 code input is developed. The results show that for 6.27 MPa pressure in steam generators and air temperature of 36 ° C, the system is able to remove 95.52 MW heat.