Sodium Flow Test for Dummy Core Fuel Sudassemdlies of Prototype Fast Breeder Reactor MONJU (on Pressure Loss Increase of MONJU Dummy Core Fuel Subassemblies)

Fujimoto, Tetsuro*; Sato, Kazujiro*; Takahashi, June*

The 4,800-hours flow test for MONJU dummy core fuel subassemblies was carried out at sodium flow rate of 19.5 - 20.2 kg/sec. subassembly, sodium temperature of 600, oxygen impurities in sodium of 2 - 2.5ppm which are about the same condition as that for MONJU core fuel subassemblies. The result of this test showed that the pressure loss of dummy core fuel subassemblies increased up to 11% in 3,000 hours and became constant after that. The integrity of the dummy subassemblies is planned to be investigated by disassembling them and making a material examination. On the other hand,the pressure loss increase for these subassembkies was estimated at 5.4% in case of water flow test which was carried out before and after spdium test. The cause of this difference should be investigated hereafter.