Application of phosphate modified CAC for incorporation of simulated secondary aqueous wastes in Fukushima Daiichi NPP, 1; Characterization of solidified cementitious systems with reduced water content

Garcia-Lodeiro, I.*; Lebon, R.*; Machoney, D.*; Zhang, B.*; Irisawa, Keita; Taniguchi, Takumi; Namiki, Masahiro*; Osugi, Takeshi; Meguro, Yoshihiro; Kinoshita, Hajime*

Proceedings of 3rd International Symposium on Cement-based Materials for Nuclear Wastes (NUWCEM 2018) (USB Flash Drive), 4 Pages, 2018/11

Heat treatment of phosphate-modified cementitious matrices for safe storage of secondary radioactive aqueous wastes in Fukushima Daiichi Nuclear Power Plant

Irisawa, Keita; Taniguchi, Takumi; Namiki, Masahiro; Garca-Lodeiro, I.*; Osugi, Takeshi; Sakakibara, Tetsuro; Nakazawa, Osamu; Meguro, Yoshihiro; Kinoshita, Hajime*

Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 6 Pages, 2017/04

A solidification technique with minimized water content is being developed using phosphate cements for the safe storage of secondary radioactive wastes in the Fukushima Daiichi Nuclear Power Plant. Conventional cement systems become solidified via hydration reactions, and need a certain water content. Phosphate cement systems, however, become solidified via an acid-base reaction, and so they only require water mainly for reasons of workability. A reduced water content of phosphate cement systems is beneficial for the immobilization of the radioactive wastes from mitigating the potential to generate hydrogen gas by the radiolysis of water by radioactive wastes. The current study investigated the water content and mineralogy of calcium aluminate cement (CAC) and phosphate-modified CAC (CAP) cured in open systems at 60, 90 and 120 C and in a closed system at 20 C as a reference case. Water contents in both the CAC and the CAP were seen to decrease as curing progressed. For 90 C, the CAP contained less water than CAC. Free water in CAC converted to structural water by heat treatment, but this was not the case for CAP. An orthophosphate hydrate salt, a precursor phase of hydroxyapatite, was found in CAP when cured at 20 and 60 C, and a mixture of the orthophosphate hydrate salt and hydroxyapatite, Ca(PO)(OH), were formed in the CAP when cured at 90 C. Phosphate products in CAP cured at 120 C appears to consist of a different phosphate phase compared with the CAP cured at 20, 60 and 90 C.

Research and development of CAE system for geological disposal, 2

Kurihara, Yuji*; Tokunaga, Masahiro*; Miyazaki, Kiyoshi*; Makabe, Y.*; Fukaya, Masaaki*; Ono, O.*; Namiki, Kazuto*

PNC TJ1201 92-001, 151 Pages, 1992/02

PNC-TJ1201-92-001.pdf:5.61MB

None

Development of solidification techniques with minimised water content for secondary radioactive aqueous wastes in Fukushima, 5; Leaching rate of Sr and Cl

Irisawa, Keita; Taniguchi, Takumi; Namiki, Masahiro*; Garca-Lodeiro, I.*; Osugi, Takeshi; Nakazawa, Osamu; Kinoshita, Hajime*

no journal, , 

no abstracts in English

Insolubilization of halogens using cementitious materials

Taniguchi, Takumi; Irisawa, Keita; Namiki, Masahiro*; Nakazawa, Osamu

no journal, , 

no abstracts in English

Hydrogen gas measurements of phosphate solidified products during dehydration

Irisawa, Keita; Kudo, Isamu*; Taniguchi, Takumi; Namiki, Masahiro*; Osugi, Takeshi; Nakazawa, Osamu

no journal, , 

no abstracts in English

Research and development on preceding processing methods for contaminated water management waste at Fukushima Daiichi Nuclear Power Station, 1; Examination of Task on processing

Kato, Jun; Taniguchi, Takumi; Namiki, Masahiro*; Imaizumi, Ken*; Terasawa, Toshiharu*; Osugi, Takeshi; Sone, Tomoyuki; Nakazawa, Osamu; Kuroki, Ryoichiro; Koma, Yoshikazu

no journal, , 

Regarding solidification technologies with applied performance for radioactive waste processing, tasks for applicability evaluation of these technologies to contaminated water treatment secondary waste at Fukushima Daiichi Nuclear Power Station was extracted in FY2017. This report introduces the examination for the extracted tasks implemented in FY2018.

Research and development on preceding processing methods for contaminated water management waste at Fukushima Daiichi Nuclear Power Station, 16; Consideration of quantification of method for screening test of contaminated water management waste applied to solidification by cement and Alkali Activated Material

Kakuda, Ayaka; Taniguchi, Takumi; Namiki, Masahiro*; Kikuchi, Michio*; Yamamoto, Takeshi*; Kaneda, Yoshihisa*; Osawa, Norihisa*; Osugi, Takeshi; Sone, Tomoyuki; Kuroki, Ryoichiro

no journal, , 

no abstracts in English

Research and development on preceding processing methods for contaminated water management waste at Fukushima Daiichi Nuclear Power Station, 30; Evaluation of radiation effects on solidified products containing chemical admixtures

Kakuda, Ayaka; Namiki, Masahiro*; Tabata, Koichi; Osawa, Norihisa*; Kaneda, Yoshihisa*; Kikuchi, Michio*; Yamamoto, Takeshi*; Sone, Tomoyuki; Osugi, Takeshi; Kuroki, Ryoichiro

no journal, , 

no abstracts in English