Basic test on sodium fire protection systems

Kawabe, Ryuhei*; Himeno, Yoshiaki; not registered; not registered; not registered

At Sodium Leak-Fire Basic Test Rig (SOFT-1), three tests were performed, which were : (1)Run-A1 : For the aim of understanding the sodium combustion phenomena, 180 sodium was burnt in an open pool, and temperature transients in sodium was measured and burning rate were determined. (2)Run-B1 : For the evaluation of efficiency of fire suppression board, burning sodium was covered by a slitted board and change in burning rate was observed and drain test was performed using 530 C sodium to confirm the function and integrity of draining pipe. (3)Run-B2 : In order to clarify the burning-hydraulic behavior of sodium on liner, 505C, 180 sodium was discharged onto 1.2m2.4m steel plate with 1/100 gradient, and temperature transients and mass of residuum were measured. Following results were obtained. (i)When sodium was heated up to 400C and exposed to air, the sodium was ignited. (ii)The surface temperature reached 650 C, 7 min. after the ignition and the temperature was almost constant from that. (iii)Under a conservative condition where air flowed over the fire suppression board by forced convection, the sodium burning rate and the aerosol generating rate where pool surface were covered by fire suppression board (opening area 1%) was about 3 % and 5 % of those in open pool burning respectively. (iv)The maximum heat flux to the draining pipe wall reached 1.210 W/m. Any cracking, however, was not found on the draining pipe wall even by color check. (v)In the liner test Run-B2, on the liner there remained large amount of sodium oxide, which worked as wick, and the soaked sodium burned after sodium supplying finished, resulting liner temperature 643 C which was higher than the supplied sodium temperature. The amount of sodium oxide was 8.7kg/m on the liner after the test. (vi)The maximum temperature, flow velocity and burning rate of sodium on liner and maximum heat ...