Studies of the setting of engineered barrier configuration utilized in geologic disposal, 1; Dissolution life-time of vitrified waste glass

Oe, Toshiaki*; Wakasugi, Keiichiro

Genshiryoku Bakkuendo Kenkyu (CD-ROM), 24(1), p.27 - 32, 2017/06

https://doi.org/10.3327/jnuce.24.1_27

The report estimates the life-time of the waste glass dissolution in the geologic disposal environment. The overall safety report on the geologic disposal in Japan showed very short life-time of approximately 70,000 years under pessimistic assumptions ignoring the temperature decrease due to radioactive decay and dissolution rate reduction due to surface shrinkage. These factors are physically established phenomena and may not be excluded. The dissolution models including these factors of temperature and surface area decreases are discussed and used for re-evaluation. Three fracture models are presented for evaluating the surface area decreases; a single plate, monotonic spheres, spheres having power-law distribution. All models have the same initial volume as the waste glass block for mass conservation and the total surface areas are 10 times higher than the initial pristine block because of the fracture development during production. The results indicate the retention time of 50% of initial mass exceed 100,000 years even by different fracture models and the dissolution life-times are expected for 260,000700,000 years depending on models. These results imply more strong isolation capability of the waste glass than that estimated in the overall safety report.

Burning of MOX fuels in LWRs; Fuel history effects on thermal properties of hull and end piece wastes and the repository performance

Hirano, Fumio; Sato, Seichi*; Kozaki, Tamotsu*; Inagaki, Yaohiro*; Iwasaki, Tomohiko*; Oe, Toshiaki*; Kato, Kazuyuki*; Kitayama, Kazumi*; Nagasaki, Shinya*; Niibori, Yuichi*

Journal of Nuclear Science and Technology, 49(3), p.310 - 319, 2012/03

AA2011-0278.pdf:0.56MB

https://doi.org/10.1080/00223131.2012.660021

The thermal impacts of hull and end piece wastes from the reprocessing of MOX spent fuels burned in LWRs on repository performance were investigated. The heat generation rates in MOX spent fuels and the resulting heat generation rates in hull and end piece wastes change depending on the fuel histories including the burn-up of UO spent fuels, the cooling period before reprocessing, the storage period of fresh MOX fuels. The heat generation rates of hull and end piece wastes from the reprocessing of MOX spent fuels with any of those histories are significantly larger than those from UO spent fuels with burn-ups of 45 GWd/THM. If a temperature below 80C is specified for cement-based materials used in waste packages after disposal, the allowable number of canisters containing compacted hull and end pieces in a package for 45 GWd-MOX needs to be limited to a value of 0.7 to 1.6, which is significantly lower than the value of 4.0 for 45 GWd-UO.

6th International Conference on Chemistry and Migration Behavior of Actinides and Fission Products in the Geosphere (Migration '97)

Oe, Toshiaki*; Yamaguchi, Tetsuji

Nihon Genshiryoku Gakkai-Shi, 40(1), p.47 - 49, 1998/01

no abstracts in English

Symmetric mass division process in the reactions Cl + Zn and O + Y

Nagame, Yuichiro; Ikezoe, Hiroshi; Otsuki, Tsutomu*; Yokoyama, Akihiko*; ; ; ; Sekine, Toshiaki; Ideno, K.

Physics Letters B, 249(1), p.13 - 17, 1990/10

https://doi.org/10.1016/0370-2693(90)90520-G

no abstracts in English

Statistical emission of complex fragments produced in the reaction Cl + Zn

Nagame, Yuichiro; Ikezoe, Hiroshi; ; ; Sekine, Toshiaki; ; ; Ideno, K.; Yokoyama, Akihiko*; ; et al.

Nuclear Physics A, 510, p.518 - 532, 1990/00

https://doi.org/10.1016/0375-9474(90)90064-S

no abstracts in English

Effect of substrate surface conditions before anodization on shape of Si micro-nano rolls

Qiao, Y.*; Arai, Taiki*; Suzuki, Toshiaki*; Yoshigoe, Akitaka; Niwa, Masaaki*; Motohashi, Mitsuya*

no journal, , 

Roll-like structures with a thickness of about 1 m fabricated by anodization of the surface of single-crystalline Si wafers have the potential to be applied to a variety of devices. With the aim of controlling the thickness and length of the rolls, the influence of the surface condition of the Si substrate before anodization was investigated. It was found that Pt coating before anodization was effective in controlling the thickness of rolls. Furthermore, it was found that this result was not affected by the doping types.

Surface structure of Anodic Oxide Layer with Si Micro-Nano Rolls

Arai, Taiki*; Qiao, Y.*; Suzuki, Toshiaki*; Yoshigoe, Akitaka; Niwa, Masaaki*; Motohashi, Mitsuya*

no journal, , 

In this study, it was found that the relationship between anodisation time and surface morphology after anodic oxidation of silicon oxide layers on p-type Si substrates. The unique meso-materials (Si rolls) are formed by using extremely diluted HF solution for anodization. The resistance between the electrodes during anodization initially increased with increasing anodization time and then becomes constant value. After some time, it gradually increased again. It seems to consider an important parameter to control the formation of Si rolls and those numbers.

A Study of evaluation of influence of long term topographic perturbations on groundwater flow conditions

Saegusa, Hiromitsu; Onoe, Hironori; Kinoshita, Hirohisa*; Sasao, Eiji; Kosaka, Hiroshi*; Tokusu, Mitsuhiro*; Yoden, Toshiaki*

no journal, , 

no abstracts in English

Development of micro-chemical probe for geological environment diagnosis, 15; Application of micro-chemical probe to Mizunami Undergoround Research Laboratory Project

Uchida, Masahiro; Amano, Kenji; Hama, Katsuhiro; Takeuchi, Ryuji; Yoshida, Takuma*; Noshita, Kenji*; Futakuchi, Katsuhito*; Oe, Toshiaki*; Nagasaki, Shinya*

no journal, , 

no abstracts in English

Development of micro-chemical probe for characterization of geological environment

Hama, Katsuhiro; Uchida, Masahiro; Amano, Kenji; Takeuchi, Ryuji; Hagiwara, Hiroki; Yoshida, Takuma*; Noshita, Kenji*; Nagasaki, Shinya*; Oe, Toshiaki*; Futakuchi, Katsuhito*

no journal, , 

The micro-chemical probe for characterization of geological environment has been developed. The performance test shows that this equipment can be applicable for the in-situ experiment.