Measurement of glass transition temperature of waste glass by differential thermal analysis (DTA); Research report on solidification of high-level liquid waste

Ouchi, Jin; not registered; Kawamura, Kazuhiro; not registered; not registered; Sasage, Kenichi; Odakura, Makoto 

The glass transition temperature of simulated waste glass was measured by DTA installed in CPF (Chemical Processing Facility) and HTS (High Level Waste Technology Section). This measurement was intended to confirm the agreement between hot and cold data as a part of characterization of high level waste glass. Glass transition temperature is an index of the temperature to keep thermal stability of high-level waste glass. Since devitrification deteriorates characteristics of waste glass above glass transition temperature, it is necessary to measure glass transition temperature and keep glass temperature below glass transition temperature. The conventional method to determine glass transition temperature is the measurement of thermal expansion, but DTA is adopted for radioactive sample because of easier preparation. We obtained following results by measuring glass transition temperature of simulated waste glasses after calibration with standard specimen : (1)The average glass transition temperature of TVF waste glass (P0798) measured by DTA in HTS and CPF was 494C (standard deviation 3 : 8.2C) and 495C (3: 1.8C), respectively. The difference between two analyzer was 1C. It shows the good agreement between hot and cold DTA data. (2)Glass transition temperature of P0798 measured by thermal expansion method was 495C(3: 8.1C) and it agrees well with that measured by DTA. (3)The average glass transition temperature of simulated highly waste-loading glass (P1102) measured by DTA in HTS and CPF was 510.5 2.5C.