An Evaluation of gas generation from metal wastes, III

Wada, Ryutaro*; Nishimura, Tsutomu*; Inaba, Masayuki*; Fujiwara, Kazuo*; Tateishi, Tsuyoshi*

In order to evaluate the hydrogen gas generation rate due to the corrosion of metallic materials contained in TRU wastes, the ampoule type immersion tests (the test specimen and test solution are enclosed into a glass ampoule) have been performed following the last year. The gas generation tests on single metal of zircaloy and stainless steel were continued for longer immersion time, and the gas generation tests on single metal of carbon steel and dissimilar metals were added in this year. (1)The hydrogen gas generation rate due to the corrosion of zircaloy in simulated underground water (pH103.5) decreased with the immersion time, and the equivalent corrosion rate after immersion of 230 days ranged in 10 10 m/y. (2)The hydrogen gas generation rate due to the corrosion of stainless steel (SUS304) in simulated underground water (PH103.5) generally tended to decrease with immersion time, but increasing tendency was also recognized in the high pH range. The equivalent corrosion rate after immersion of 230 days ranged in 1010 m/y. (3)The hydrogen gas generation rate due to the corrosion of carbon steel (SS400) in simulated underground water (pH1013.5) ranged in equivalent corrosion rate of about 0.023 m/y depending on the composition of test solution, and the ranking by pH of solution was pH10 pH13.5 PH12.5. (4)The effects of electrical contact of zircaloy or stainless steel on the hydrogen gas generation rate from carbon steel have not remarkably been recognized. (5)By continuing these tests for longer time hereafter, the reliability of these data must furthermore be raised. In addition as a thema nearafter, gas generation rate under unsaturated condition considering the first stage of disposal should be evaluated.