Study on solubility and leaching property of Iodine-129 waste-forms for geological disposal

Yanagisawa, Ichiro*; Katsurai, Kiyomichi*; Izumi, Jun*; Saigusa, Moriyuki*; *; *; *; Ueta, Shinzo*

JNC TJ8400 2000-038, 202 Pages, 2000/02

JNC-TJ8400-2000-038.pdf:15.12MB

(1)Sodalite and tourmaline are natural-occurring minerals, which can contain halide in their aluminosilicate lattices. Therefore, these materials have possibilities of immobilization of I-129. In this study, solubility measurements for these materials were carried out. It was confirmed from dissolution behaviors obtained for some kinds of sodalite and calculated results of solubilities based on thermodynamic data that dissolution of sodalite to aqueous solution could be limited by its solubility. Solubility of sodalite had tendencies of "synthesized one natural one" and "chloride iodide". Immobilized iodine in sodalite crystalline lattice was not replaced by chlolide ion in the solution. It was indicated that tourmaline has a possibility as a waste material containing I-129 from comparison of dissolution behavior of element with sodalite. (2)Leaching property of a multi-layered waste-form, that is composed of (1)iodine bearing material (zeolite), (2)coating layer (silica and apatite) and 3)low solubility matirx (apatite), was studied under reducing condition. The following results were obtained by the leaching experiments: (1)The coating layer of hidroxyapatite can reduce the iodine leaching rate by 4 order compared with that of bare iodine bearing material. (2)Ca and P concentration after one-month dipping reached the solubility estimated by the theoretical calculation using PHREEQE code. As a conclusion, it was indicated that this waste-form concept has potential to show low leaching rate.

Reliability study on the assessment method for the geochemical phenomena of geological disposal

*; Katsurai, Kiyomichi*; Saigusa, Moriyuki*; *; Kitao, Hideo*; Tsuzuki, Yasuo*

JNC TJ8400 2000-012, 333 Pages, 2000/02

JNC-TJ8400-2000-012.pdf:11.14MB

In this study, technical review, laboratory experiment and modeling calculations were implemented in order to reliability of geochemical assessment technique for the second progress report. The summary of this study is as follows: (1)We have implemented the technical review of the second progress backup report geochemical modeling and some data. We have extracted a subject about groundwater evolution modeling and thermodynamic data. (2)We have implemented multivariable analysis based on database of deep groundwater sampled in geoscientofic investigation in other countries. We have considered validity of peculiar model groundwater of SRLP, FRLP and MRNP. (3)We have researched on redox reaction of a coastal sedimentary layer, and was cleared geochemical mechanism of dedox reaction. (4)We have studied thermodynamic of Se in laboratory. We have confirmed condition, which SRB was not in experimental system, initial solid transformed to solid phase (FeSe). And we have clarified chemical species of Se in the liquid phase. (5)We have researched on degradation of the engineered barrier material. We have prepared natural analogue data set that related to the iron and cooper. And we have acquired basic property of buffer material (Kunipia-F) in laboratory. (6)We have studied on dissolution kinetic of UO in order to extract geochemistry technical factor for site selection. The dissolution rates in oxidized groundwater may be much slower than previously believed by most scientists. Therefore, oxidized environments, as well as reduced environments, may be considered as possible sites for underground repository sites.

Development of Equipment for Disposal of Contaminated Sodium (2)

Tomioka, Yutaka*; Saigusa, Moriyuki*; Nakajima, Nobuo*; Osawa, Yasutaka*

PNC TN251 77-13, 32 Pages, 1977/05

PNC-TN251-77-13.pdf:2.95MB

The transport behavior of trace-amount of radio nuclides such as I and Cs (Cs) in sodium have been studied on both conditions of normal sodium-steam reaction and sodium burning brought by excess steam supplying. trapping of these radio nuclides transported into gas phase in gas bubbler or scrubber, which is a component of waste gas treatment system, was also discussed. main experimental results were as follows: (1) under the normal sodium-steam reaction, partition ratio of Cs trans-ported into gas phase was 410, while those of I and Na were one hundred times smaller than that of 134cs. Chemical forms of Cs and I transported into gas phase were estimated to be cesium hydroxide and inorganic iodine such as nai, respectively. (2) when the sodium burning occurred by excess steam supplying, partitionratios of Na, I increased 250500 times larger than those under the normal sodium-steam reaction, while for Cs, it increased about 25 times larger than that under normal reaction. sma

Evaluation of radioactivity in wastes from Tokai reprocessing plant, 5; Correlation between activation products and Co-60, 1

Kino, Kenichiro*; Saigusa, Moriyuki*; Sakashita, Akira*; Kuroda, Kazuhiko*; Sakakibara, Tetsuro; Kohanawa, Osamu; Akutsu, Shigeru; Kojima, Hiroshi

no journal, , 

no abstracts in English