Chemical composition of insoluble residue generated at the Rokkasho Reprocessing Plant

Yamagishi, Isao; Odakura, Makoto; Ichige, Yoshiaki; Kuroha, Mitsuhiko; Takano, Masahide; Akabori, Mitsuo; Yoshioka, Masahiro*

Proceedings of 21st International Conference & Exhibition; Nuclear Fuel Cycle for a Low-Carbon Future (GLOBAL 2015) (USB Flash Drive), p.1113 - 1119, 2015/09

The characteristics of insoluble residues in fine suspension at the Rokkasho Reprocessing Plant were analyzed. The insoluble residues were washed with oxalic acid solution to dissolve zirconium molybdate residues. XRD profiles of unwashed residues showed the presence of a noble metal alloy, zirconium molybdate, and zirconia, but zirconium molybdate was not found after washing. More than 50% of the Sb-125 and Pu in thee residues was washed out as well. The noble metal alloy composed of Mo, Tc, Ru, Rh, and Pd occupied more than 90% of the total weight of 12 elements (Ca, Cr, Fe, Ni, Zr, Mo, Tc, Ru, Rh, Pd, Te, and U) found in the residues. In consideration of the chemical forms of 12 elements, the alloy-to-residue weight ratio was evaluated to be 64% and 78% with and without 18% of an unknown component, respectively.

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

Ouchi, Jin; ; Kawamura, Kazuhiro; *; ; Sasage, Kenichi; Odakura, Makoto

PNC TN8410 97-044, 53 Pages, 1997/03

PNC-TN8410-97-044.pdf:1.36MB

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.

None

Okawa, Aoi; Kawamura, Kazuhiro; ; Yamada, Kazuo; Odakura, Makoto

Denki Kyokai Zasshi, 10, , 

None

Migration behavior of radionuclides from fully radioactive waste glass in compacted sodium bentonite

Fujiwara, Kenso; Iijima, Kazuki; Mitsui, Seiichiro; Odakura, Makoto; Kohara, Yukitoshi*; Kikuchi, Hiroshi*

no journal, , 

The in-diffusion experiment was carried out for about 15 years to evaluate the migration behavior of multivalent actinide and lanthanide elements by using fully radioactive waste glass and bentonite. The experimental concentrations of Am, Cm and Pu in contact with compacted sodium bentonite were good agreement with the solubilities calculated by thermodynamic data. The profiles of Am and Cm show two different slopes which be fitted by simple one-dimensional diffusion model each other.