[1D05-07] Solubility

[1D07] Evaluation of dissolution rate of simulated high-level nuclear waste glass P0798 under Silica Dissolved Solution Conditions: long term behavior

*Noriyuki Yokoyama¹, Yaohiro Inagaki¹, Tatsumi Arima¹, Ryuta Matsubara² (1. Kyushu Univ., 2. NUMO)

Keywords:Nuclear waste glass, Dissolution rate, Dissolved Si concentration, Silicon isotope, Microchannel Flow-Through Test

High-level nuclear waste glass is predicted to begin to corrode by contact with groundwater a thousand years after closure of the repository, which leads to release of radioactive nuclides from the repository. The corrosion behavior of glass depends on the chemical properties of groundwater. In this study, microchannel flow-through test was conducted on a Japanese reference waste glass P0798 under Si-dissolved conditions ([Si]=50ppm) using Si-29 isotopes for up to 90 days. As a result, under the conditions of pH 9 and 90℃, the glass dissolution rate gradually decreased after 25 days, confirming that the alteration phase growing on the glass surface has a barrier function to inhibit glass corrosion.