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Journal Articles

Hydrogen gas measurements of phosphate cement irradiated during heat treatment

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

QST-M-16; QST Takasaki Annual Report 2017, P. 63, 2019/03

no abstracts in English

Journal Articles

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

Journal Articles

Characterization of phosphate cement irradiated by $$gamma$$-ray during dehydration

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

QST-M-8; QST Takasaki Annual Report 2016, P. 63, 2018/03

A solidification technique with minimized water content is being developed using a phosphate cement for safe storage of secondary radioactive wastes in the Fukushima Daiichi Nuclear Power Plant. To understand the applicability of the solidification technique for the actual secondary wastes, phosphate cement during dehydration was irradiated by $$^{60}$$Co $$gamma$$-ray. The G(H$$_{2}$$) for the phosphate cement decreased with time during dehydration, and was not detected after 7 days. Moreover, the $$^{60}$$Co $$gamma$$-ray irradiation during dehydration did not change the crystalline and amorphous phases of the phosphate cement.

Journal Articles

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; Garc$'i$a-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 $$^{circ}$$C and in a closed system at 20 $$^{circ}$$C as a reference case. Water contents in both the CAC and the CAP were seen to decrease as curing progressed. For $$geq$$ 90 $$^{circ}$$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 $$^{circ}$$C, and a mixture of the orthophosphate hydrate salt and hydroxyapatite, Ca$$_{10}$$(PO$$_{4}$$)$$_{6}$$(OH)$$_{2}$$, were formed in the CAP when cured at 90 $$^{circ}$$C. Phosphate products in CAP cured at 120 $$^{circ}$$C appears to consist of a different phosphate phase compared with the CAP cured at 20, 60 and 90 $$^{circ}$$C.

JAEA Reports

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 92-002, 45 Pages, 1992/02

PNC-TJ1201-92-002.pdf:2.93MB

None

JAEA Reports

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

Oral presentation

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

Oral presentation

Development of solidification techniques with minimised water content for secondary radioactive aqueous wastes in Fukushima, 5; Leaching rate of Sr$$^{2+}$$ and Cl$$^{-}$$

Irisawa, Keita; Taniguchi, Takumi; Namiki, Masahiro*; Garc$'i$a-Lodeiro, I.*; Osugi, Takeshi; Nakazawa, Osamu; Kinoshita, Hajime*

no journal, , 

no abstracts in English

Oral presentation

Influence of $$^{60}$$Co $$gamma$$-ray on characteristics of phosphate cements synthesized during dehydration

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

no journal, , 

no abstracts in English

Oral presentation

Insolubilization of halogens using cementitious materials

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

no journal, , 

no abstracts in English

Oral presentation

Application of phosphate modified CAC for incorporation of simulated secondary aqueous wastes in Fukushima Daiichi NPP, 2; Leaching test of simulated wasteforms with reduced water content

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

no journal, , 

Oral presentation

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

Oral presentation

Research and development on preceding processing methods for contaminated water management waste at Fukushima Daiichi Nuclear Power Station, 5; Gamma-ray irradiation test on solidified body of cement and Alkali Activated Material

Taniguchi, Takumi; Imaizumi, Ken*; Namiki, Masahiro*; Osugi, Takeshi; Kuroki, Ryoichiro; Kikuchi, Michio*; Yamamoto, Takeshi*; Kaneda, Yoshihisa*; Haga, Kazuko*

no journal, , 

It is important to understand fundamental solidification characteristics of contaminated water management waste at Fukushima Daiichi Nuclear Power Station. The Solidified bodies are fabricated with cementitious material and Alkali Activated Material, and are irradiated with Gamma-ray.

Oral presentation

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.

14 (Records 1-14 displayed on this page)
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