Wall temperature variation during water reflood

In a nuclear reactor system, the emergency core cooling system (ECCS) provides backup to the cooling system for prevent the melt of core and fuel assembly especially at the Loss of coolant accident (LOCA). In this state as like LOCA, firstly blowdwon occurred in the reactor core after that control rod is inject to the core for shutdown for core. But decay heat emitted in fuel assembly it is 6% of operating power. It can be cooled by injected coolant by the reflooding. If it doesn’t rapidly removed by coolant, nuclear fuel can be melted by high temperature and exposed by fission gas.

Injected water interacts with heated wall. In this situation, reflood shows phase change. We investigate reflood state with phenomenon. Furthermore, we research the enhanced coolant by using nanofluid. Enhanced coolant can be adopted for coolant for ECCS. It can useful to increase of operation time in the accident.

Facility of reflood experiment

Cladding surface temperature during LOCA

Wall temperature variation during water reflood