Safety assessment of Tehran Research Reactor fuel test loop during loss of flow accident

In order to enhance applicability of Tehran Research Reactor (TRR) for irradiation test of nuclear fuels and materials and considering TRR potential to provide required neutronic and thermal-hydraulic conditions for irradiation tests on domestic nuclear fuel samples, TRR fuel test loop is designed and fabricated. This test loop with 10 bar nominal pressure and 20m3/h nominal volumetric flow rate is designed to simulate thermal-hydraulic conditions of the reactor core in which, the fuels will be used.  In this research, safety assessment of the consequences of loss of flow accident in the fuel test loop due to primary pump breakdown is performed and the functions of safety systems to provide continuous cooling for the test fuel samples and also to mitigate any undesirable consequences of this accident are evaluated. In this regard, the probable scenarios are simulated using a RELAP5 model and the ability of the safety features of the loop to prevent any damage to the test fuel rods is evaluated. The results reveal that safety systems of test loop can provide safe condition during the accident in which the meat and clad temperatures of test fuels remain within the permissible limits.