Analysis of Loss of Coolant Accident in MTR Pool Type Research Reactors

Abstract During the operation lifetime of a Nuclear Research Reactors, the frequency of occurrence of LOCA event is expected to be very seldom. In case of MTR pool type research reactor, a loss of coolant accident could occur as consequence of a rupture of a pipe of the primary cooling system or a break of an experimental beam tube. The objective of the present work is to investigate the behaviour of the fuel elements during a total loss of coolant accident. Under these conditions, the internal natural circulation of the fluid is suppressed due to total loss of the coolant but there still convection by air of the containment. This hypothetical scenario has been simulated by applying the RELAP5/Mod 3.2 code system to the IAEA 10MW benchmark research reactor. The obtained results has shown that in case of complete loss of coolant in the pool, the maximum cladding temperature reached is below the melting point (~ 500°C) for a research reactor operating at nominal power of 4 MW. For A 10MW operating reactor, the melting is observed few seconds after the complete pool drainage after only 16 min of the beginning of the acciden