Investigation for the sodium leak Monju; Sodium fire test-II

not registered; Takai, Toshihide  ; not registered ; not registered  ; Miyake, Osamu; Tanabe, Hiromi

As a part of the work for investigating the sodium leak accident which occurred in the Monju reactor (hereinafter referred to as Monju), sodium fire test-II was carried out using, the SOLFA-1 (Sodium Leak, Fire and Aerosol) facility at OEC/PNC. ln the test, the piping, ventilation duct, grating and floor liner were all full-sized and arranged in a rectangular concrete cell in the same manner as in Monju. The main objectives of the test were to confirm the leak and burning behavior of sodium from the damaged thermometer, and the effects of the sodium fire on the integrity of the surrounding structure. The main conclusions obtajned from the test are shown below: (1)Burning Behavior of Leaked Sodium : lmages taken with a cameras in the test reveal that in the early stages of the sodium leak, the sodium dropped down out of the flexible tube in drips. (2)Damage to the ventilation Duct and Grating: The temperature of the ventilation duct's inner surface fluctuated between approximately 600C and 700C. The temperature of the grating began rising at the outset of the test, then fluctuated betvveen roughly 600C and 900C. The maximum temperature was about 1000C. After the test, damage to the ventilation duct and the grating was found. Damage to the duct was greater than that at Monju. (3)Effects on the Floor Liner : The temperature of the floor liner under the leak point exceed l,000C at 3 hours and 20 minutes into the test. A post test inspection of the liner revealed five holes in an area about 1m 1m square under the leak point. There was also a decrease of the liner thickness on the north and west side of the leak point. (4)Effects on Concrete: The post test inspection revealed no surface damage on either the concrete side walls or the ceiling. However, the floor concrete was eroded to a maximum depth 8 cm due to a sodium-concrete reaction. The compressive strength of the ...