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JAEA Reports

Removal and storage of asbestos-containing materials used in radiation controlled areas

Ishida, Reiya; Aoki, Emi; Sonobe, Hiroshi; Oto, Tsutomu; Kimura, Akihiro

JAEA-Review 2026-019, 50 Pages, 2026/07

JAEA-Review-2026-019.pdf:5.3MB

Subsequent to a leakage incident in October 2012 involving the SFC waste liquid transfer piping in the C Trench, additional leakage incidents occurred in the No. 4 drainage system piping and the SFC waste resin transfer piping. Furthermore, leakage incidents occurred in the tank yard, including seepage at welded joints in the waste liquid piping, as well as leakage from the waste liquid tanks. Since these incidents, the transfer of liquid waste from the hot laboratory facility to the JMTR tank yard has been suspended. Currently, as the waste liquid piping in the JMTR tank yard and the waste liquid tanks receiving liquid waste from the hot laboratory have been replaced and in sound condition, a plans is being developed to resume liquid waste transfer. To confirm the integrity of the waste liquid piping system, which runs from the hot laboratory through the C Trench to the tank yard, radiographic testing (hereafter referred to as "RT") of the pipe welds will be conducted. As it has been confirmed that the waste liquid piping is wrapped with asbestos-containing thermal insulation materials, these materials will be removed from the piping prior to RT. During this removal work, it is essential to comply with applicable laws and regulations and to ensure worker safety. This report summarizes the plan for removal of asbestos-containing thermal insulation materials in radiation controlled areas in order to minimize asbestos-related risks, as well as the procedures for the removal work and the methods for storage management.

Journal Articles

High-temperature gaseous reaction of cesium with siliceous thermal insulation; The Potential implication to the provenance of enigmatic Fukushima cesium-bearing material

Rizaal, M.; Nakajima, Kunihisa; Saito, Takumi*; Osaka, Masahiko; Okamoto, Koji*

ACS Omega (Internet), 7(33), p.29326 - 29336, 2022/08

https://doi.org/10.1021/acsomega.2c03525

Times Cited Count：7 Percentile：33.68(Chemistry, Multidisciplinary)

Journal Articles

Investigation of high-temperature chemical interaction of calcium silicate insulation and cesium hydroxide

Rizaal, M.; Nakajima, Kunihisa; Saito, Takumi*; Osaka, Masahiko; Okamoto, Koji*

Journal of Nuclear Science and Technology, 57(9), p.1062 - 1073, 2020/09

https://doi.org/10.1080/00223131.2020.1755733

Times Cited Count：10 Percentile：61.25(Nuclear Science & Technology)

The interaction of cesium hydroxide and a calcium silicate insulation material was experimentally investigated at high temperature conditions. A thermogravimetry equipped with differential thermal analysis was used to analyze thermal events in the samples of mixed calcium silicate and cesium hydroxide under Ar-5%H $_{2}$ and Ar-4%H $_{2}$ -20%H $_{2}$ 0 with maximum temperature of 1100 $^{circ}$ C. Prior being mixed with cesium hydroxide, a part of calcium silicate was pretreated at high temperature to evaluate the effect of possible structural changes of this material due to a preceding thermal history and also the sake of thermodynamic evaluation to those available ones. Based upon the initial condition (preliminary heat treatment) of calcium silicate, it was found that if the original material consisted of xonotlite (Ca $_{6}$ Si $_{6}$ 0 $_{17}$ (0H) $_{2}$ ), the endothermic reaction with cesium hydroxide occurred over the temperature range 575-730 $^{circ}$ C meanwhile if the crystal phase of original material was changed to wollastonite (CaSi0 $_{3}$ ), the interaction occurred over temperature range 700-1100 $^{circ}$ C. Furthermore, the X-ray diffraction analyses have indicated on both type of pretreated calsils that regardless of Ar-5%H $_{2}$ and Ar-4%H $_{2}$ -20%H $_{2}$ 0 atmosphere, cesium aluminum silicate, CsAlSi0 $_{4}$ was formed with aluminum in the samples as an impurity or adduct.