Irradiation experiments of simulated wastes of carbonate slurry

Nagaishi, Ryuji; Motooka, Takafumi; Yamagishi, Isao

Proceedings of 2016 EFCOG Nuclear & Facility Safety Workshop (Internet), 6 Pages, 2016/09

BB2016-0884.pdf:1.24MB

Overflow of water from waste storage tanks of High Integrity Containers (HIC) in the multi-nuclide removal equipment (ALPS) was discovered at Fukushima Daiichi NPS in April of last year. The mechanism of overflow was not understood very much at that time. To elucidate that for chemical safety in the waste storage, irradiation experiments of simulated carbonate slurry by Co-60 -rays have been conducted in CLADS, JAEA in cooperation with TEPCO, TOSHIBA and KURITA. Hydrogen molecule was the main radiolytic gas product in the slurry, and its amount was enhanced by dissolved species of not only halide ions as seawater components but also carbonate ion as an additive for co-precipitation at a basic condition. The bubbles of molecules were further formed and almost held in the slurry without stirred. These sequentially led to the expansion of slurry, and then to its separation into the shrunk one and supernatant water, which was little accumulated without irradiated.

Development of solidification techniques with minimised water content for secondary radioactive aqueous wastes in Fukushima, 1; Synthesis and evaluation of simulated wastes

Taniguchi, Takumi; Irisawa, Keita; Ito, Yuzuru; Namiki, Masahiro; Osugi, Takeshi; Abe, Tomohisa; Sato, Junya; Sakakibara, Tetsuro; Nakazawa, Osamu; Meguro, Yoshihiro; et al.

no journal, , 

no abstracts in English

Research and development on preceding processing methods for contaminated water management waste at Fukushima Daiichi Nuclear Power Station, 9; Synthesis of simulated carbonate slurry

Nakashio, Nobuyuki*; Kawasoe, Takahiro*; Aikawa, Kohei*; Kikuchi, Michio*; Yamamoto, Takeshi*; Kaneda, Yoshihisa*; Haga, Kazuko*; Osugi, Takeshi; Sone, Tomoyuki; Kuroki, Ryoichiro

no journal, , 

Simulated carbonate slurry was synthesized to obtain basic data for the low temperature processing of the waste generated from contaminated water treatment at Fukushima Daiichi Nuclear Power Station. An overview of the study and some of the results obtained are reported here.

Research and development on preceding processing methods for contaminated water management waste at Fukushima Daiichi Nuclear Power Station, 11; Dissolution test of solidified body of cement and Alkali Activated Material

Kaneda, Yoshihisa*; Haga, Kazuko*; Shibata, Masahito*; Osawa, Norihisa*; Kikuchi, Michio*; Yamamoto, Takeshi*; Kawato, Takaya*; Osugi, Takeshi; Sone, Tomoyuki; Kuroki, Ryoichiro

no journal, , 

Solidified cement and alkali activated material blending carbonated slurry were prepared and their dissolution tests were carried out in order to obtain basic data for the low temperature processing of the waste generated by contaminated water treatment at Fukushima Daiichi Nuclear Power Station. An overview of the study and some of the results obtained are reported here.

Research and development on preceding processing methods for contaminated water management wasteat Fukushima Daiichi Nuclear Power Station, 24; Experimental and modeling studies on the dissolution behavior of cement solidified body with modified wastes

Kobayashi, Yutaro*; Haga, Kazuko*; Kaneda, Yoshihisa*; Sato, Tsutomu*; Kakuda, Ayaka; Osugi, Takeshi; Sone, Tomoyuki; Kuroki, Ryoichiro

no journal, , 

no abstracts in English

Radiolysis studies on H retention with changing hydrophilicity of carbonate slurry, 1; Estimation of hydrophilicity on the surface of suspended solid

Kuwano, Ryo*; Nagaishi, Ryuji; Ito, Tatsuya

no journal, , 

The overflow event occurred in carbonate slurry wastes emitted from the 1F ALPS co-precipitation system is due to the highly viscous slurry retaining hydrogen molecules (H) formed by its radiolysis. Since this high viscosity is caused by the hydrophilicity (water absorption) of surface of suspended solid (SS) particle in the slurry, it is expected that H retention would be repressed by coating (modifying) this surface with much lower hydrophilic materials (molecules). In order to discuss the degree of repression quantitatively, it is important to estimate the hydrophilicity of SS particle surface. In this report as the first in a series of presentations, the water vapor adsorption behavior on the SS particle surface was measured under two conditions of drying and moisture adsorption by using a gas adsorption measurement apparatus, and the hydrophilicity of SS particle surface was estimated for the current and hydrophilicity-lowered slurries to be compared with each other.

Radiolysis studies on H retention with changing hydrophilicity of carbonate slurry, 2; Pulse radiolysis measurement of local (partial) viscosity of pore water

Nagaishi, Ryuji; Kuwano, Ryo*; Ito, Tatsuya; Godo, Masao*; Yoshida, Yoichi*; Tamaki, Ryoya*

no journal, , 

Hydrogen molecules (H) retained by highly viscous suspension such as a carbonate slurry exist in the pore water of suspension in the form of gas (bubble). The H behaviors such as the reaction of dissolved species of H and the process forming H bubble are mainly determined by the viscosity of pore water, while the H retention by the macroscopic viscosity of suspension. Such local (partial) viscosity is generally unclear. In order to clarify the H retention/release mechanism in the suspension, it is important to estimate this viscosity. In this report as the second in a series of presentations, the reaction (decay) rate of hydrated electrons (e) formed as a radiolysis radical of pore water was transiently measured by using ns-pulse radiolysis, and the viscosity of pore water was estimated for the current and hydrophilicity-lowered slurries to be compared with each other.

Characterization of carbonate slurry prepared by coagulation and sedimentation process with sludge circulating, 2; Bubble formation and retention in the irradiated slurry

Yamagishi, Isao; Kato, Tomoaki

no journal, , 

no abstracts in English