Experiences of an Air Bubble Rise in the HANARO Reactor Pool

HANARO is an open-tank-in-pool type research reactor operated by KAERI. Its thermal power is 30 MW and the core is immersed in the reactor pool whose depth is about 12 m. It also has a service pool used for services such as an irradiation target change and the visual inspection of targets or fuel, and a spent fuel storage pool. During a normal operation, the reactor pool and the service pool is connected There are several paths through which the air could permeate into the primary cooling system and the pool water. If air bubbles which have radioactive isotopes, rise through the pool, the radiation level at the pool surface may increase. This is not desirable for a stable and safe operation. This paper describes the experiences of an air bubble rise through the pool and the counter measures undertaken to prevent a bubble rise