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Aoyagi, Kazuhei; Ishii, Eiichi
Environmental Earth Sciences, 83(3), p.98_1 - 98_15, 2024/02
Times Cited Count：0 Percentile：0.04(Environmental Sciences)The long-term geological disposal of high-level radioactive waste relies on predictions of future changes in a disposal facility's hydro-mechanical characteristics to assess potential leakage through fractures in the excavation damaged zone (EDZ) after backfilling the facility. This study evaluated the transmissivity of EDZ fractures using in situ hydraulic tests around the area of a full-scale, experimental, engineered barrier system in the Horonobe Underground Research Laboratory, Hokkaido, Japan. After their installation, the buffer blocks swelled, altering the stresses within the EDZ fractures. The effects of these changing stresses on the fractures' transmissivity were assessed over a period of 4 years. The transmissivity continuously decreased in this period to about 41% of its value measured prior to the swelling. Using the Barton-Bandis normal-stress-dependent fracture-closure model, the decrease in transmissivity is quantitatively attributed to closure of the EDZ fractures, which was caused by the swelling pressure increasing up to 0.88 MPa. Evidence of fracture closure came from seismic tomography surveying, which revealed a slight increase in seismic velocity in the study area with increasing swelling pressure. The results show that EDZ fractures were closed by swelling of the full-scale buffer material. They also demonstrate the applicability of the Barton-Bandis model to preliminary estimation of the long-term transmissivity of EDZ fractures in facilities for the geological disposal of radioactive waste.
Tachi, Yukio
Kagaku To Kyoiku, 71(10), p.420 - 423, 2023/10
no abstracts in English
Osawa, Hideaki; Matsui, Hideki
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 28(2), p.18 - 25, 2021/12
The Japan Atomic Energy Agency had offered visitor's tour to the underground and surface facilities of the Mizunami Underground Research Laboratory (URL) at the Tono Geoscience Center in order to promote the understanding of the R&D of geological disposal technology and geological disposal for the public. We analyzed questionnaires distributed after visiting these facilities from FY2010 to FY2019, except for FY2016, in the hopes of using risk communication for geological disposal. Results suggest that visiting these facilities is a valuable experience to understand geological disposal because some people, knew even just a little bit about it, have positively evaluated appropriateness of geological disposal by a tour of the Mizunami URL. While some people who have negatively evaluated safety of geological disposal are highly interested in issues of nuclear power and site selection, some people who have positively evaluated safety of geological disposal are highly interested in public understanding of geological disposal. Furthermore, both these groups believe that long-term safety is a technical issue.
Ogawa, Yusuke*; Suzuki, Satoru*; Taniguchi, Naoki; Kawasaki, Manabu*; Suzuki, Hiroyuki*; Takahashi, Rieko*
Materials and Corrosion, 72(1-2), p.52 - 66, 2021/01
Times Cited Count：2 Percentile：12.73(Materials Science, Multidisciplinary)Cast steel is one of the promising alternative to forged steel that is the current reference material for carbon steel overpack. In this study, the full-scale cast steel overpack was produced experimentally and the distribution of casting defects were investigated. The corrosion test regarding corrosion rate and stress corrosion cracking (SCC) susceptibility were also conducted using samples taken from the full-scale cast steel overpack and the corrosion resistance of cast steel was compared with that of forged steel. From above two corrosion tests, it can be said that the corrosion resistance of cast steel is mostly the same as that of forged steel.
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
Geological Disposal Research and Development Department
JAEA-Evaluation 2019-010, 69 Pages, 2020/01
JAEA-Evaluation-2019-010.pdf:2.54MB
JAEA-Evaluation-2019-010-appendix(CD-ROM).zip:13.88MB
Japan Atomic Energy Agency (JAEA) consulted the advisory committee, "Evaluation Committee on Research and Development (R&D) Activities for Geological Disposal of High-Level Radioactive Waste", for an interim review of R&D activities on high-level radioactive waste disposal in accordance with "General Guideline for the Evaluation of Government Research and Development (R&D) Activities" by the Cabinet Office, Government of Japan, "Guideline for Evaluation of R&D in Ministry of Education, Culture, Sports, Science and Technology" and JAEA's "Regulation on Conduct for Evaluation of R&D Activities". In response to JAEA's request, the Committee reviewed mainly the progress of the R&D project on geological disposal, the relevance of the project outcome during the period of FY2015-2018. This report summarizes the results of the assessment by the Committee with the Committee report attached.
Osawa, Hideaki; Nogami, Toshinobu; Hoshino, Masato; Tokunaga, Hiroaki*; Horikoshi, Hidehiko*
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 26(1), p.45 - 55, 2019/06
Japan Atomic Energy Agency has performed risk communication at Horonobe Underground Research Center, using the Public Information House and Underground Research Laboratory (URL), to promote understanding R&D of geological disposal technology and waste disposal against public. In this paper, we conducted the analysis of questionnaire investigation performing after visiting those facilities from FY2013 to FY2017. The results show that long-term safety would gain prominent attention as agita factor by growing understanding. The results also shows that visiting to those facility would become valuable experience to understand geological disposal because, for example, respondents with visiting to URL positively evaluated necessity, appropriates and safety of geological disposal, compared with those without visiting URL.
Osawa, Hideaki; Otomo, Shoji*; Hirose, Yukio*; Onuma, Susumu*
Ningen Kankyogaku Kenkyu, 17(1), p.59 - 64, 2019/06
This study examined the determinants of public acceptance of siting a repository for High-level radioactive waste (HLW), focusing on procedural fairness and trust. To examine the presumption, the study implemented a hypothetical scenario experiment that manipulated two factors: an opportunity of voice as an antecedent of procedural fairness and similarity value to the authority as a component of trust. Results indicated that affective reaction, procedural fairness, and trust determined public acceptance. A process analysis indicated that the effect of procedural fairness was strengthened when the trust on similarity was negative.
Osawa, Hideaki; Hirose, Yukio*; Onuma, Susumu*; Otomo, Shoji*
Shakai Anzengaku Kenkyu, 9, p.145 - 160, 2019/03
We compared decision-making process on selection of management policy for high-level radioactive waste between Switzerland and UK by document review. The decision-making was performed extraction of options, establishment of comparative criteria, assessment and selection of options in turn. As comparative criteria, safety and intergenerational fairness etc. were considered to be important. The position of 'Deal with it now by waste disposal' emphasizing the responsibility of the present generation had a trade-off relation with that of 'Leave it until later by long-term storage' emphasizing the rights of future generations. The sense of values, recusing HLW repository as so-called troublesome facility against future and present generation, appeared to be mitigated through the consideration of trade-off relation described above. As a result, both countries have chosen waste disposal considering reversibility of decisions and retrievability of radioactive waste.
Osawa, Hideaki; Hirose, Yukio*; Onuma, Susumu*; Otomo, Shoji*
Shakai Anzengaku Kenkyu, 9, p.161 - 176, 2019/03
We compared site selection process by a voluntarism and partnership approach in UK, and that by screening based primarily on technical criteria with the main emphasis on safety in Switzerland, by document review. The voluntarism and partnership approach in UK is based on the ethical consideration that fairness in siting facilities could only be achieved by the enhancement of well-being and public acceptability based on a willingness to participate and a right to withdraw from a siting process. On the other hand, it could be interpreted that the screening approach with the main emphasis on safety in Switzerland would be based on the concept of the ignorance of veil, hypothesized that people would accept the decision if they consent the decision way beforehand under condition everyone could be involved in as a potential interest party.
Onuma, Susumu*; Hirose, Yukio*; Osawa, Hideaki; Otomo, Shoji*; Yokoyama, Miki*
Nihon Risuku Kenkyu Gakkai Dai-31-Kai Nenji Taikai Koen Rombunshu (USB Flash Drive), 6 Pages, 2018/11
One reason of not being decided a candidate site for geological disposal of high level radioactive waste is that strong opposition occurs once a name of the place where residents live even if they can understand the necessity of the facility. Therefore, we hypothesized that people would accept the decision if they consent the decision way beforehand under the condition everyone can be involved in as a potential interest party (the ignorance of veil). A hypothetical scenario survey was conducted in Japan. The results revealed that the decision way and the decision under the ignorance of veil were likely to be accepted more than the current decision way even if they became candidate site. Moreover, the decision way under the ignorance of veil was evaluated higher procedural fairness, while the current way was low procedural fairness.
O in Fe
O
film on Fe formed in an NaOH solution containing oxidantsHaruna, Takumi*; Miyataki, Yuki*; Hirohata, Yohei*; Shibata, Toshio*; Taniguchi, Naoki; Tachikawa, Hirokazu*
Zairyo To Kankyo, 67(9), p.375 - 380, 2018/09
This research aimed to confirm the formation of FeO film on Fe immersed in aqueous 45 mass% NaOH solution containing some oxidants at the boiling temperature, to recognize the optimum immersion time for the formation of thick and protective film, and to reveal the absorption behavior of DO in the FeO film at room temperature. The results were obtained as follows. It was confirmed that FeO film was formed on Fe immersed in the NaOH solution for a time more than 0.6 ks, and the film thickness increased parabolically with an increase in the immersion time. DO absorption test was carried out to the films formed in the NaOH solution for immersion times of 1.2 and 3.6 ks. An amount of DO absorbed into the film increased with an increase in an absorption time up to 1000 ks, and an absorption time more than 1000 ks made an amount of DO constant. The constant amount of DO was larger for the film formed on Fe immersed in the NaOH solution for 3.6 ks than that for 1.2 ks. The transient of the amount of DO absorbed into the film was analyzed on the basis of Fick's law for diffusion, and diffusion coefficients of DO were obtained to be 5.1
10
cm
s
and 9.910 cm s for the films formed for 1.2 and 3.6 ks, respectively. Therefore it was estimated that the diffusion coefficient of the FeO film was in the region from 5.110 cm s to 9.910 cm s.
Hanamuro, Takahiro
JAEA-Review 2018-011, 20 Pages, 2018/08
JAEA-Review-2018-011.pdf:2.77MB
As part of the research and development program on geological disposal of high-level radioactive waste (HLW), the Horonobe Underground Research Center, a division of the Japan Atomic Energy Agency (JAEA), is implementing the Horonobe Underground Research Laboratory Project (Horonobe URL Project) with the aim at investigating sedimentary rock formations. According to the research plan described in the 3rd Mid- and Long-term Plan of JAEA, according to the Horonobe URL Project, "Near-field performance study", "Demonstration of repository design option", and "Verification of crustal-movement buffering capacity of sedimentary rocks" are the top priority issues, and schedule for finishing the project and backfill plan will be decides by the end of 2019 Fiscal Year. The Horonobe URL Project is planned to extend over a period of about 20 years. This report summarizes the investigation program for the 2018 fiscal year (2018/2019).
Aoyagi, Kazuhei; Miyara, Nobukatsu; Ishii, Eiichi; Matsuzaki, Yoshiteru
Shigen, Sozai Koenshu (Internet), 5(1), 7 Pages, 2018/03
no abstracts in English
Amamoto, Ippei
Journal of the Society of Inorganic Materials, Japan, 24(391), p.393 - 401, 2017/11
Glass is a non-crystalline solid, as such, it is relatively easy to change its composition to control its characteristics. The borosilicate glass, which is produced by the addition of boron oxide into sodium-lime glass, possesses excellent heat-resistant properties and mechanical strength. It has a wide variety of uses. The borosilicate glass is applied as the vitrified medium for radioactive wastes to immobilize and stabilize them for long term. The glass form which is loaded with high-level radioactive waste is called the vitrified waste. This paper classified the radioactive waste and describes treatment and production methods of vitrified waste, its characteristics, disposal method and also introduces alternative vitrified medium.
Hanamuro, Takahiro
JAEA-Review 2017-013, 22 Pages, 2017/06
JAEA-Review-2017-013.pdf:2.85MB
As part of the research and development program on geological disposal of high-level radioactive waste (HLW), the Horonobe Underground Research Center, a division of the Japan Atomic Energy Agency (JAEA), is implementing the Horonobe Underground Research Laboratory Project (Horonobe URL Project) with the aim at investigating sedimentary rock formations. According to the research plan described in the 3rd Mid- and Long-term Plan of JAEA, according to the Horonobe URL Project, "Near-field performance study", "Demonstration of repository design option", and "Verification of crustal-movement buffering capacity of sedimentary rocks" are the top priority issues, and schedule for finishing the project and backfill plan will be decides by the end of 2019 Fiscal Year. The Horonobe URL Project is planned to extend over a period of about 20 years. This report summarizes the investigation program for the 2017 fiscal year (2017/2018).
Taniguchi, Naoki
Zairyo To Kankyo, 65(9), p.363 - 364, 2016/09
no abstracts in English
Hanamuro, Takahiro
JAEA-Review 2016-010, 22 Pages, 2016/07
JAEA-Review-2016-010.pdf:2.98MB
As part of the research and development program on geological disposal of high-level radioactive waste (HLW), the Horonobe Underground Research Center, a division of the Japan Atomic Energy Agency (JAEA), is implementing the Horonobe Underground Research Laboratory Project (Horonobe URL Project) with the aim at investigating sedimentary rock formations. According to the research plan described in the 3rd Mid- and Long-term Plan of JAEA, according to the Horonobe URL Project, "Near-field performance study", "Demonstration of repository design option", and "Verification of crustal-movement buffering capacity of sedimentary rocks" are the top priority issues, and schedule for finishing the project and backfill plan will be decides by the end of 2019 Fiscal Year. The Horonobe URL Project is planned to extend over a period of about 20 years. This report summarizes the investigation program for the 2016 fiscal year (2016/2017).
Nishio, Kazuhisa*; Osawa, Hideaki
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 23(1), p.9 - 24, 2016/06
Japan Atomic Energy Agency (JAEA) has promoted the Mizunami Underground Research Laboratory (Mizunami URL) as one of generic URL to perform basic research of waste disposal technology for about twenty years. JAEA had carried out consultation activities with local people and community from 1995 when the plan of Mizunami URL opened at the time, because an early approach of JAEA caused a sense of social distrust and concern, which the study area of Mizunami URL would be candidate site of real repository. In this paper, we conducted normative analysis intended for the consultation activities from a viewpoint of procedural justice and distributed justice, used as the social psychological framework in terms of public NIMBY facility. The results show that it is important to develop local partnership, composed of representative local people and organization at early start and to support deliberation by local partnership in the aspect of information and financial administration.
Osawa, Hideaki; Otomo, Shoji*; Onuma, Susumu*; Hirose, Yukio*
Shakai Gijutsu Kenkyu Rombunshu, 13, p.86 - 95, 2016/05
This study examined determinants of public acceptance regarding siting a geological disposal facility for high-level radioactive waste (HLW) in France, where a candidate site has been selected following on a variety of public involvement activities. Data from 886 French residents were collected in 2014 by an internet survey that was performed near a district that is a candidate for a HLW repository and in an outlying region away from the candidate site. Results indicate that procedural fairness, intergenerational subjective norm, public benefit and personal benefit were significant factors for public acceptance in dealing with the NIMBY issue in addition to factors such as trust, risk perception and stigma, dealt with in previous research on risk analysis. Furthermore, personal benefit and affect had stronger impact on the acceptance than public benefit, procedural fairness and intergenerational subjective norm.
