Loss of Electric Power Supply Transient in an Irradiation Test Loop of HFRR

High flux research reactor (HFRR) is a 40 MW pool type research reactor being developed at BARC for providing various facilities for basic and applied research in nuclear science and technology, neutron radiography, neutron transmutation doping and material irradiation studies. In this reactor, an irradiation test loop (ITL) is provided to support fuel and material testing under simulated conditions present in light water power reactors (PWR/BWR). It is a high pressure and high temperature loop with operating pressures reaching up to 17.5 MPa whereas the temperatures as high as 330 °C. Specific provisions are also made to simulate water chemistry environment as present in various PWR/BWR reactor types. To evaluate process system design of the ITL, thermal hydraulic transient analysis was carried out to assess thermal parameters and safety margins of the test fuel during loss of electric power supply using RELAP5/MOD 3.2. It was found that the ITL process system provides sufficient cooling flow to the test fuel cluster to maintain all the thermal hydraulic parameters and safety margins under the acceptable limits during loss of electric power supply.