Safety analysis of HWRR test fuel assembly in Tehran Research Reactor core using open loop test facility

HWRR element is an instrumented fuel assembly constructed based on JCPOA conceptual design parameters for Arak reactor. The in-core experiments of the fuel are carried out in TRR core to evaluate neutronic and thermal-hydraulic parameters using an experimental facility called Open Loop Test Facility (OLTF). Safety analysis of the OLTF anticipated incidents is one of the necessary steps before its implementation. Therefore, three severe anticipated accident scenarios have been simulated, including two LOFA scenarios and the instant post SCRAM cooling by natural circulation. The neutronic calculation has been carried out by MCNPX code to determine fuel rods power and thermal-hydraulic analysis using CFD method. The analysis results show that the clad surface temperature violates coolant saturation temperature and void will arise in both LOFA scenarios. However, both clad and fuel temperatures keep significant margins to their design criteria and fuel rod integrity would be retained completely. The results also show that the coolant temperature remains lower than saturation temperature in the case of decay heat removing via natural cooling scenario.