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Hanamachi, Yuji*; Walker, C.*; Sasamoto, Hiroshi; Mihara, Morihiro
NIMS Bisai Kozo Kaiseki Purattofuomu Riyo Hokokusho (Internet), 2 Pages, 2023/12
A High-volume Fly ash Silica fume Cement (HFSC) has been considered as the use of concrete support of drift in deep disposal of radioactive wastes. JAEA has been carried out experiments and modeling studies to evaluate chemical stability of C-A-S-H gel synthesized which would be believed as the dominant component of the HFSC. For the modeling purpose, it is necessary to evaluate the chemical composition both of C-A-S-H gel synthesized and accompanied minerals in the experiment. In the year of 2020, 
Al and 
Si NMR measurement were performed to identify Al and Si distribution in the sample and chemical composition of C-A-S-H gel was derived. However, it was impossible to derive the C-A-S-H gel composition having the expected Al/Si molar ratio since there were several accompanied minerals produced in the experiment due to the short term of immersion. This time similar approach to derive C-A-S-H gel composition is adopted using NMR measurement for the sample of longer time (6 months).
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.
Nakayama, Masashi
JAEA-Technology 2018-006, 43 Pages, 2018/08
JAEA-Technology-2018-006.pdf:5.32MB
JAEA-Technology-2018-006-appendix(CD-ROM).zip:29.19MB
The Horonobe URL Project has being pursued by JAEA to enhance the reliability of relevant disposal technologies through investigations of the deep geological environment within the host sedimentary formation at Horonobe, Hokkaido. The URL Project proceeds in 3 overlapping phases, "Phase I: Surface-based investigations", "Phase II: Investigations during tunnel excavation" and "Phase III: Investigations in the underground facilities", over a period of around 20 years. The OP corrosion test was prepared from 2013 FY at Niche No.3, and heating by electric heater in simulated overpack started in November, 2014. The objective of the test is acquiring data concerned with corrosion of carbon steel OP. These data will be used in order to confirm the performance of engineered barrier system. In the OP corrosion test, the diameter of simulated OP and buffer material are 100 mm and 300 mm, respectively. Concrete support using low alkaline cement was used in order to investigate the effect of cementitious materials to OP corrosion behavior. We will measure corrosion potential of carbon steel, natural potential, pH in buffer material for several years. In this report, we describe how to make simulated OP and buffer material blocks, and set sensors, and so on.
Nakayama, Masashi; Niunoya, Sumio*; Miura, Norihiko*; Takeda, Nobufumi*
JAEA-Research 2017-016, 62 Pages, 2018/01
JAEA-Research-2017-016.pdf:19.99MB
The Horonobe URL Project has being pursued by JAEA to enhance the reliability of relevant disposal technologies through investigations of the deep geological environment within the host sedimentary formation at Horonobe, Hokkaido. The URL Project consists of 2 major research areas, "Geoscientific Research" and "Research and Development on Geological Disposal Technologies", and proceeds in 3 overlapping phases, over a period of around 20 years. Phase III (Investigations in the underground facilities) investigation was started in 2010 FY. The in-situ experiment for performance confirmation of engineered barrier system (EBS experiment) had started 2013 at GL-350 m gallery, and heating by electric heater in simulated overpack had started in January, 2015. One of objectives of the EBS experiment is acquiring data concerned with THMC coupled behavior. These data will be used in order to confirm the performance of engineered barrier system. This report shows consideration of concrete-type plug composition. The low alkaline cement developed by JAEA, called HFSC, was used for the plug. HFSC has used in construction test at the gallery as shotcrete in Horonobe URL.
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.
Cs(
= 1.63 m) by ABMRPinard, J.*; Duong, H. T.*; Marescaux, D.*; Stroke, H. H.*; Redi, O.*; Gustafsson, M.*; Nilsson, T.*; Matsuki, S.*; Kishimoto, Yasuaki*; Kominato, K.*; et al.
Nuclear Physics A, 753(1-2), p.3 - 12, 2005/05
Times Cited Count：4 Percentile：35.96(Physics, Nuclear)The hfs separation 
of Cs(
m) in the 6s 
S ground state was obtained in a precision measurement near zero magnetic field by means of atomic beam magnetic resonance with laser optical pumping on-line with the CERN-PSB-ISOLDE mass separator. The result, 
MHz, corrects significantly a previous published value from a high-field experiment. With our result, the precision of the nuclear magnetic moment, 
Cs)
, is now limited by the influence of extended nuclear structure on the hfs (the Bohr-Weisskopf effect).
Suganuma, Kazuaki; Anami, Shozo*; Chishiro, Etsuji; Kubota, Chikashi*; Shinohara, Kibatsu*; Tsuruoka, Shigetsugu*; Yamaguchi, Seiya*
Proceedings of 1st Annual Meeting of Particle Accelerator Society of Japan and 29th Linear Accelerator Meeting in Japan, p.275 - 277, 2004/08
A 972MHz circlator is currently developed. In the high-power test of the prototype,rf breakdown was observed at the matching post. Rf characterristics obtained by simulations and low-power tests will be presented.
Suganuma, Kazuaki; Anami, Shozo*; Kubota, Chikashi*; Chishiro, Etsuji; Yamaguchi, Seiya*
Proceedings of 28th Linear Accelerator Meeting in Japan, p.78 - 80, 2003/08
This report a design and adjustment of 324MHz Waveguide System of The J-PARC LINAC.
; Sekine, Toshiaki; Oshima, Masumi; ; Nakahara, Yoshinori
Nuclear Instruments and Methods in Physics Research B, 70, p.93 - 100, 1992/00
Times Cited Count：15 Percentile：78.33(Instruments & Instrumentation)no abstracts in English
Ozawa, K.; Kawatsura, Kiyoshi; *; *; *
Atomic Collision Res.,Prog.Rep., (4), p.62 - 63, 1978/04
no abstracts in English
Walker, C.*; Anraku, Sohtaro; Sasamoto, Hiroshi; Mihara, Morihiro
no journal, ,
A thermodynamically credible calcium(-aluminate)-silicate-hydrate (C(-A)-S-H) gel solubility model has to consider a variety of features, including structure, composition, phase boundaries, measured/estimated thermodynamic properties, molar volumes, and, of course, solubility behavior in terms of pH values and Ca, Al and Si concentrations expressed as a function of C(-A)-S-H gel composition, temperature and ionic strength. This study provides an account of the rapidly growing body of data that are concerned with these features and of the more promising approaches that can be used to develop a C(-A)-S-H gel solubility model. JAEA research on the degradation of high content fly ash silica fume cement (HFSC) provides a good working example that highlights the need to develop a C(-A)-S-H gel solubility model.
Matsui, Hiroya; Motoshima, Takayuki*; Shibata, Masahito*; Sakamoto, Ryo*; Mochizuki, Akihito
no journal, ,
no abstracts in English
