Initial dissolution rate of a Japanese simulated high-level waste glass P0798 as a function of pH and temperature measured by using micro-channel flow-through test method

Inagaki, Yaohiro*; Makigaki, Hikaru; Idemitsu, Kazuya*; Arima, Tatsumi*; Mitsui, Seiichiro  ; Noshita, Kenji*

Dissolution tests were performed for a simulated HLW glass by using a Micro-Channel Flow-Through (MCFT) test to evaluate the initial dissolution rate, , as a function of pH and temperature. The results indicated that the shows a "V-shaped" pH dependence at 25C, which is almost consistent with the previous results measured by using other test methods including Single Pass Flow-Through (SPFT) test. At elevated temperatures, however, the shows a "U-shaped" pH dependence with a flat bottom at neutral pH, which differs from the previous results. The results also indicated that the MCFT provided a higher value of the with a steep slope of pH dependence than the SPFT results at basic pH from 8 to 11 at 90C. With respect to the temperature dependence, the increases with temperature according to an Arrhenius law at any pH, and the apparent activation energy increases with pH, which suggests that the dissolution mechanism can change depending on pH.