Experimental Study on Lithium Leakage Behavior

In the Japanese engineering validation activities on the target facility of the International Fusion Materials Irradiation Facility, two studies on the advanced lithium leak detection system and the fire-extinguishing behavior of lithium were performed. In the former study, the fluorescence was distinguishable from the background using the difference of decay curves from the results of the lithium fluorescence measurement under two lithium concentration (256 ng/L and 4.58 ng/L) in argon. This result shows the basic applicability of the laser based lithium measuring technique as the lithium detector could be confirmed. In the latter study, fire-extinguishing behavior of two kinds of carbon base fire extionguishishants — MITEX and GRAPHEX — to lithium was examined. The both extinguishants showed excellent fire-extinguishing performance, and there were equivalent to that of Natlex-L obtained in the previous study. Since the bulk densities of the both carbon based extinguishants were about equal to the density of lithium, the subsidence of the fire-extinguishings which was observed in the Natlex-L was not observed. In fact, it was considered that no dependency of lithium pool depth on the required thickness of the fire extinguishants was observed for the carbon based extinguishants.