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Sasagawa, Tsuyoshi; Mukai, Masayuki; Sawaguchi, Takuma
JAEA-Data/Code 2021-012, 122 Pages, 2022/01
JAEA-Data-Code-2021-012.pdf:3.87MB
Reducing public dose is required when radioactive wastes such as high-level and from reactor core internals etc. are disposed of by means of multi barrier system consist of engineered and natural barriers. In these barriers, engineered barrier is expected to bring out confinement function of waste's radionuclides in the barrier. Materials used as the engineered barriers are altered and performances of the barrier materials are degraded in course of time. To estimate properly the degraded performances, analytical evaluation of long-term change of the engineered barrier state is important. Change state of the engineered barrier is given by mass-transport and geochemical-reaction inside the barrier materials and these phenomena are interrelated, it is necessary to calculate the state by means of coupled analysis procedure. We have developed a coupled mass-transport and geochemical-reaction calculation code (MC- BUFFER) to evaluate alteration of engineered barrier specially targeted for water permeability of bentonite buffer material as one of most important performances to engineered barrier. This report describes functions expected for the engineered barrier, influence parameters for the functions, implementation models in MC-BUFFER, structure and functions of MC-BUFFER, input file format and output examples, execution method of MC-BUFFER, and sample run with MC-BUFFER.
Walker, C.*
NIMS Bisai Kozo Kaiseki Purattofuomu Riyo Hokokusho (Internet), 2 Pages, 2021/09
High content fly ash silica fume cement (HFSC) has been considering a candidate low alkali cements for the geological disposal of radioactive waste in Japan. JAEA has been currently performing many experiments and modeling studies relevant to validation for the long-term stability of the C-A-S-H gel which is a dominant component of the HFSC. For developing the C-A-S-H model of hydration and degradation, it is necessary to determine the composition of C-A-S-H gel and accompanied minerals when it reacts with water. In the present subject, the synthesized sample of C-A-S-H gels were analyzed by using the NMR spectra of 
Al and 
Si to determine the coordination of these element in the C-A-S-H gel.
Kobayashi, Keita; Nakamura, Hiroki; Yamaguchi, Akiko; Itakura, Mitsuhiro; Machida, Masahiko; Okumura, Masahiko
Computational Materials Science, 188, p.110173_1 - 110173_14, 2021/02
Times Cited Count：14 Percentile：73.11(Materials Science, Multidisciplinary)no abstracts in English
Sawaguchi, Takuma
"Yugai Haikibutsu, Hoshasei Haikibutsu Eno Semento, Konkurito Gijutsu No Tekiyo Kenkyu Iinkai" Hokokusho (CD-ROM), p.165 - 173, 2020/12
no abstracts in English
Guo, B.*; Xiong, Y.*; Chen, W.*; Saslow, S. A.*; Kozai, Naofumi; Onuki, Toshihiko*; Dabo, I.*; Sasaki, Keiko*
Journal of Hazardous Materials, 389, p.121880_1 - 121880_11, 2020/05
Times Cited Count：43 Percentile：90.61(Engineering, Environmental)Mihara, Morihiro; Harasawa, Shuichi*; Torii, Kazuyuki*
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 26(1), p.15 - 23, 2019/06
Hardened cement pastes (HCPs) of water/cement ratio (W/C) 50% and 30% using fly ash (FA), blast furnace slag (BFS) and silica fume (SF) for 28 days were prepared. Apparent diffusion coefficients (D
) of Cs and I in HCPs were obtained using electron probe microanalysis. For Cs, BFS and SF contributed to a reduction of D for W/C=50% and 30%, respectively. For I, BFS reduced D for W/C=50%, however a significant reduction in D for W/C=30% was not observed. Using SF enhanced sorption of Cs on HCP, and using BFS slightly improved sorption of Cs on HCP. It was also confirmed that the pore structures of HCP using SF and BFS were connected by fine pores. It was therefore considered that using SF and BFS contributes to the reduction of D in HCP.
Iwatsuki, Teruki; Shibata, Masahito*; Murakami, Hiroaki; Watanabe, Yusuke; Fukuda, Kenji
Doboku Gakkai Rombunshu, G (Kankyo) (Internet), 75(1), p.42 - 54, 2019/03
In order to clarify the influence of shotcrete in the underground facility on the groundwater chemistry, an in-situ closed test was conducted in the mock-up tunnel at the depth of 500 m. Brucite, Ettringite, Ca(OH) 
, Gibbsite, KCO
, NaCO 
10HO, SiO (a) and Calcite were identified as the dominant minerals affecting the water chemistry. Furthermore, the shotcrete constructed in the tunnel has a reaction capacity which can produce about 570 m
of alkaline groundwater (pH12.4) saturated with Ca(OH). The estimation would improve the accuracy of prediction analysis of the long-term chemical influence of cement materials after the closure of the tunnel.
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
Matsushima, Ryotatsu; Sato, Fuminori; Saito, Yasuo; Atarashi, Daiki*
Proceedings of 3rd International Symposium on Cement-based Materials for Nuclear Wastes (NUWCEM 2018) (USB Flash Drive), 4 Pages, 2018/10
At TRP, LWTF was constructed as a facility for processing low radioactive liquid waste and solid waste generated at TRP, and a cold test is been carrying out. In this facility, initially, nitrate waste liquid after separation of nuclides generated with treatment of low radioactive liquid waste was to be solidified by using borate. However, at present, it is necessary to decompose the nitrate in the liquid waste to reduce the environmental burden. For the reason, as a plan to replace the nitrate with the carbonate and to make it as a cement based encapsulation, we are studying for the introduction of the facility. Currently, as a cement solidification technology development for this liquid waste, we are studying the application of cement material based on blast furnace slag (BFS) as a main component. In this report, we show the results of the test conducted on the actual scale (200 L drum can scale).
Hamamoto, Takafumi*; Matsubara, Ryuta*; Shibutani, Sanae*; Suyama, Tadahiro*; Tachi, Yukio
JAEA-Data/Code 2017-014, 31 Pages, 2018/03
JAEA-Data-Code-2017-014.pdf:2.1MB
JAEA-Data-Code-2017-014-appendix(CD-ROM).zip:0.61MB
NUMO and JAEA have developed the methodology of post-closure safety assessment for the geological disposal. For this purpose, NUMO and JAEA have conducted a collaborative research project for developing the safety assessment methodology based on international state of the art knowledge. The present report focuses on investigation of sorption and diffusion data reported and their QA evaluation for updating sorption and diffusion database (SDB and DDB) as the collaborative research project between NUMO and JAEA. This report includes sorption and diffusion data for mainly sedimentary rocks and cement materials. As a result, 1,746 sorption data from 19 references and 593 diffusion data from 25 references were extracted and prepared in the datasheet of SDB and DDB.
-ray during dehydrationIrisawa, 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 
Co -ray. The G(H) for the phosphate cement decreased with time during dehydration, and was not detected after 7 days. Moreover, the Co -ray irradiation during dehydration did not change the crystalline and amorphous phases of the phosphate cement.
Ito, Yoshiyuki; Matsushima, Ryotatsu; Sato, Fuminori
QST-M-8; QST Takasaki Annual Report 2016, P. 69, 2018/03
no abstracts in English
Sato, Junya; Kikuchi, Hiroshi*; Kato, Jun; Sakakibara, Tetsuro; Matsushima, Ryotatsu; Sato, Fuminori; Kojima, Junji; Nakazawa, Osamu
QST-M-8; QST Takasaki Annual Report 2016, P. 62, 2018/03
no abstracts in English
Shirase, Mitsuyasu*; Abe, Akimasa*; Nago, Makito*; Ishii, Eiichi; Aoyagi, Kazuhei; Wakasugi, Shinichi*
Doboku Gakkai Heisei-29-Nendo Zenkoku Taikai Dai-72-Kai Nenji Gakujutsu Koenkai Koen Gaiyoshu (DVD-ROM), p.1795 - 1796, 2017/09
JAEA has executed the underground facility construction operation from February 2011 to June 2014, while carrying out the maintenance and research project until 2018. This report is about the extra high head pump which was able to drain the high specific gravity grout drainage, which develops during grouting operation at this facility, directly from 250m underground to the surface.
Mihara, Morihiro; Hirano, Fumio; Takayama, Yusuke; Kyokawa, Hiroyuki*; Ono, Shintaro*
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 24(1), p.15 - 25, 2017/06
A computer program MACBECE has been developed to provide rigorous calculations of the long-term mechanical behavior of a TRU waste geological repository. Consideration is given to the expected chemical alteration of repository components, including cementitious materials and bentonite, and the mechanical interactions between repository and host rock. The long-term mechanical behavior of a TRU waste repository was evaluated in a deep soft rock site, where creep deformation is likely to occur from the initial construction phase to 10
years after repository closure. It was found that the stress didn't fall into a singularity of yield surface of the EC model applied to the mechanical behavior model of bentonite. The calculated displacement of the inner diameter of the repository, considering mechanical interaction between repository and host rock, was about half that of a result in 2nd progress report on R&D for TRU waste disposal in Japan.
Seno, Yasuhiro*; Nakayama, Masashi; Sugita, Yutaka; Tanai, Kenji; Fujita, Tomoo
JAEA-Data/Code 2016-011, 164 Pages, 2016/11
JAEA-Data-Code-2016-011.pdf:8.45MBJAEA-Data-Code-2016-011-appendix(CD-ROM).zip:0.1MB
The cementitious materials are used as candidate materials for the tunnel support of the deep geological repository of high-level radioactive wastes (HLW).Generally the pH of leachate from concrete mixed Ordinary Portland Cement (OPC) shows a range of 12 to 13. The barrier function of bentonite used as a buffer material and that of host rock might be damaged by the high alkaline leachate from cementitious materials. Therefore, low alkalinity that does not damage each barrier function is necessary for cementitious materials used for the tunnel support system of the HLW geological repository. JAEA has developed a low alkaline cement named as HFSC (Highly Fly-ash contained Silicafume Cement) which the pH of the cement leachate could lower approximately 11. We have confirmed the applicability of HFSC for the tunnel support materials, by using experimentally as the shotcreting materials to the part of gallery wall at 140m, 250m and 350m depth in Horonobe Underground Research Laboratory. And moreover, HFSC has been used as the cast-in-place concrete for the shaft lining concrete at the depth of 374m-380m. This Data/Code summarized the past HFSC mix proportion test results about the fresh concrete properties and hardened concrete properties, in order to offer the information as a reference for selecting the mix proportion of HFSC concrete adopted to the disposal galleries et al. in the future.
Seno, Yasuhiro*; Noguchi, Akira*; Nakayama, Masashi; Sugita, Yutaka; Suto, Shunkichi; Tanai, Kenji; Fujita, Tomoo; Sato, Haruo*
JAEA-Technology 2016-011, 20 Pages, 2016/07
JAEA-Technology-2016-011.pdf:7.56MB
Cementitious materials are expected to be used for the construction of an underground repository for the geological disposal of radioactive wastes. Ordinary Portland Cement(OPC) would conventionally be used in the fields of civil engineering and architecture, however, OPC has the potential to generate a highly alkaline plume (pH
12.5), which will likely degrade the performance of other barriers in the repository such as the bentonite buffer and/or host rock. Low alkaline cementitious materials are therefore being developed that will mitigate the generation of a highly alkaline plume. JAEA has developed a High-volume Fly ash Silica fume Cement (HFSC) as a candidate low alkaline cementitious material. The workability of the HFSC shotcrete was confirmed by conducting In-situ full scale construction tests in the Horonobe underground research laboratory. This report summarizes the results of immersion tests to assess the long-term pH behavior of hardened HFSC cement pastes made with mix designs that are expected to be able to be used in the construction of an underground repository in Japan.
Nakayama, Takuya; Kawato, Yoshimi; Osugi, Takeshi; Shimazaki, Takejiro; Hanada, Keiji; Suzuki, Shinji; Sakakibara, Tetsuro; Nakazawa, Osamu; Meguro, Yoshihiro
JAEA-Technology 2014-046, 56 Pages, 2015/03
JAEA-Technology-2014-046.pdf:7.61MB
The combustible and flame-retardant radioactive wastes generated as a result of the research activities in Japan Atomic Energy Agency (JAEA) are incinerating to reduce their volume. The incinerated ash is planned to be solidified using cement for disposal. Since the properties of ashes generated in each institute of JAEA are varied with the type of incinerator and the wastes to be incinerated, it is necessary to do fundamental solidification tests in each institute to decide operating conditions of the planning cement solidification facility. It is important to standardize evaluating methods of cement and solidified waste because some characters depend on measuring method. This user's guide have been prepared how to decide the cement solidifying conditions of ash to design the cement solidification facility in JAEA. Requirements on the regulations of solidified radioactive waste have been examined and seven technical criteria, e.g. compressive strength, fluidity, have been selected as characters to be evaluated. Some empirical notes about selection of cement, admixtures, procedure on making a test piece, evaluation of expanding, compressive strength, solubility have been described. The strategy of tests and tips for finding optimized solidification condition has been summarized. Finally the example of optimized conditions satisfied the requirements and some problems to be solved have been described.
Otani, Hiroshi; Mizui, Hiroyuki; Higashiura, Norikazu; Bando, Fumio*; Endo, Nobuyuki*; Yamagishi, Ryuichiro*; Kume, Kyo*
Heisei-25-Nendo Koeki Zaidan Hojin Wakasawan Enerugi Kenkyu Senta kenkyu Nempo, 16, P. 66, 2014/10
no abstracts in English
Maeda, Toshikatsu; Bamba, Tsunetaka*; Mizuno, Tsuyoshi*; Terakado, Shogo; Kitagawa, Isamu; Numata, Masami
Haikibutsu Gakkai Rombunshi, 17(4), p.271 - 281, 2006/07
no abstracts in English
