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Geological Disposal Research and Development Department
JAEA-Evaluation 2022-007, 81 Pages, 2022/11
JAEA-Evaluation-2022-007.pdf:2.06MB
JAEA-Evaluation-2022-007-appendix(CD-ROM).zip:37.06MB
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 post- and pre-review assessment 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 and the efficiency of the project implementation during the period of the current and next plan. This report summarizes the results of the assessment by the Committee with the Committee report attached.
Shiba, Tomooki; Tomikawa, Hirofumi; Yamaguchi, Tomoki
Dai-41-Kai Nihon Kaku Busshitsu Kanri Gakkai Nenji Taikai Kaigi Rombunshu (Internet), 4 Pages, 2020/11
Shiba, Tomooki; Tomikawa, Hirofumi
Nihon Kaku Busshitsu Kanri Gakkai Dai-40-Kai Nenji Taikai Puroshidhingusushu, 3 Pages, 2019/11
no abstracts in English
Fukaya, Yuji; Goto, Minoru; Ohashi, Hirofumi; Nishihara, Tetsuo; Tsubata, Yasuhiro; Matsumura, Tatsuro
Annals of Nuclear Energy, 116, p.224 - 234, 2018/06
Times Cited Count：2 Percentile：20.93(Nuclear Science & Technology)Optimization of disposal method and scenario to reduce volume of High Level Waste (HLW) and the footprint in a geological repository for High Temperature Gas-cooled Reactor (HTGR) has been performed. It was found that HTGR has great advantages to reducing HLW volume and its footprint, which are high burn-up, high thermal efficiency and pin-in-block type fuel, compared with those of LWR and has potential to reduce those more in the previous study. In this study, the scenario is optimized, and the geological repository layout is designed with the horizontal emplacement based on the KBS-3H concept instead of the vertical emplacement based on KBS-3V concept employed in the previous study. As a result, for direct disposal, the repository footprint can be reduced by 20 % by employing the horizontal without change of the scenario. By extending 40 years for cooling time before disposal, the footprint can be reduced by 50 %. For disposal with reprocessing, the number of canister generation can be reduced by 20 % by extending cooling time of 1.5 years between the discharge and reprocessing. The footprint per electricity generation can be reduced by 80 % by extending 40 years before disposal. Moreover, by employing four-group partitioning technology without transmutation, the footprint can be reduced by 90 % with cooling time of 150 years.
Fukaya, Yuji; Nishihara, Tetsuo
Nuclear Engineering and Design, 307, p.188 - 196, 2016/10
Times Cited Count：4 Percentile：36.53(Nuclear Science & Technology)Reduction of High Level Waste (HLW) and footprint in a geological repository due to high burn-up and high thermal efficiency of High Temperature Gas-cooled Reactor (HTGR) has been investigated. A helium-cooled and graphite-moderated commercial HTGR was designed as a Gas Turbine High Temperature Reactor (GTHTR300), and the features are significantly high burn-up of approximately 120 GWd/t, high thermal efficiency around 50%, and pin-in-block type fuel. The pin-in-block type fuel was employed to reduce processed graphite volume in reprocessing, and effective waste loading method for direct disposal is proposed by applying the feature in this study. As a result, it is found that the number of canisters and its repository footprint per electricity generation can be reduced by 60% compared with LWR representative case for direct disposal because of the higher burn-up, higher thermal efficiency, less TRU generation, and effective waste loading proposed in this study for HTGR. For disposal with reprocessing, the number of canisters and its repository footprint per electricity generation can be reduced by 30% compared with LWR because of the 30% higher thermal efficiency of HTGR.
Kitamura, Akira; Chikazawa, Takahiro*; Akahori, Kuniaki*; Tachi, Yukio
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 23(1), p.55 - 72, 2016/06
The Japanese geological disposal program has started researching disposal of spent nuclear fuel (SF) in deep geological strata (hereafter "direct disposal of SF") as an alternative management option other reprocessing followed by vitrification and geological disposal of high-level radioactive waste. We conducted literature survey of dissolution rate of SF matrix and constructing materials (e.g. zircaloy cladding and control rods) selected in safety assessment reports for direct disposal of SF in Europe and United States. We also investigated basis of release rate determination and assignment of uncertainties in the safety assessment reports. Furthermore, we summarized major conclusions proposed by some European projects governed by European Commission. It was found that determined release rates are fairly similar to each other due to use of similar literature data in all countries of interest. It was also found that the determined release rates were including conservativeness because it was difficult to assign uncertainties quantitatively. It is expected that these findings are useful as fundamental information for determination of the release rates for the safety assessment of Japanese SF disposal system.
irradiationYukawa, Takuji*; Inoue, Hiroyuki*; Kojima, Takao*; Iwase, Akihiro*; Taniguchi, Naoki; Tachikawa, Hirokazu*
Zairyo To Kankyo 2016 Koenshu (CD-ROM), p.359 - 362, 2016/05
The immersion tests of pure titanium were carried out in aqueous solution containing carbonate/bicarbonate with 50 mM-chloride ion under gamma irradiation. The effect of pH on general corrosion rate of titanium were studied. The experimental results showed that the concentration of hydrogen preoxide was increased with pH, and the corrosion rate increased with the hydrogen preoxide concentration. The corrosion rate in pH12 and 13 were 5 to10 times larger than those under unirradiated conditions.
Radioactive Waste Processing and Disposal Research Department
JAEA-Research 2015-016, 327 Pages, 2015/12
JAEA-Research-2015-016.pdf:41.98MB
The Japan Atomic Energy Agency has prepared the technical progress report on preliminary assessment of geological disposal for spent fuel (hereinafter referred to as "First Progress Report on Direct Disposal"). This report is aiming to examine the technical feasibility of the direct disposal of spent fuel in Japan, based on the results of research and development (R&D) on SF direct disposal carried out during FY 2013. In the First Progress Report on Direct Disposal, the available technology for the direct disposal of spent fuel in Japan was discussed through the preliminary design and safety assessment for the geological disposal system which were made under the limited conditions of representative characteristics of geological environment and spent fuel. Through R&D, the challenges and concerns on the engineering technology and the safety assessment, to be resolved for the Second Progress Report on Direct Disposal, were identified and classified.
Hatanaka, Koichiro; Shibata, Masahiro
Tekisuto "Kakunenryo Saikuru" (Internet), 6 Pages, 2014/06
no abstracts in English
Yamashita, Toshiyuki
Seramikkusu, 39(10), p.817 - 821, 2004/10
no abstracts in English
Yamashita, Toshiyuki
Look Japan, 49(567), P. 24, 2003/06
no abstracts in English
*; Okubo, Hiroo*
PNC TJ9222 95-002, 111 Pages, 1995/03
There are two methods of handling the spent fuel generated from the light water reactor; they are (l)direct disposal and (2)reprocessing-plutonium recycling. At present, Japan is following the line of "Reprocessing-Plutonium Recycling," but in the rest of the world, the movement for reviewing the Plutonium recycling is spreading, and in the future, the world opinion and pressure from overseas countries will increase against this method. Under these circumstances, Japan must compare the two methods to clarify the meaning of plutonium recycling. In this investigation, an overseas document by which the spent fuel had directly examined disposal was investigated. And, the content of those documents was arranged. The case of which directly disposed in Japan was set and the basic specification and the cost were evaluated. As a result of the investigation, the disposal cost became 54,900,000 yen/tU in the case with our country. This evaluation value is about 25% higher than Sweden and Finland where the cost is the highest in an overseas case. In cost items, the ratio which the article expense occupies is high. Moreover, the cost of construction and the close of underground facilities occupies the entire half for our country. This investigation is an evaluation based on in the case of the evaluation the current. Therefore, I want you to note going as for a technical detailed examination. However, the guess of the cost when directly disposing in Japan pounded. Moreover, the nuclear material control of the spent fuel is not evaluated. I want you to note cannot the comparison for that with the disposal of the glass solidification body.
*; Okubo, Hiroo*
PNC TJ9222 94-003, 120 Pages, 1994/06
There are two methods of handling the spent fuel generated from the light water reactor; they are (1)direct disposal and (2)reprocessing-plutonium recycling. At present, Japan is following the line of "Reprocessing-Plutonium Recycling," but in the rest of the world, the movement for reviewing the plutonium recycling is spreading, and in the future, the world opinion and pressure from overseas countries will increase against this method. Under these circumstances, Japan must compare the two methods to clarify the meaning of plutonium recycling. For this reason, the present investigation first studied the concept and trend of spent fucl disposal in overseas countries to find out what factors were regarded as important in the spent fuel policies of various countries. Further, in the present investigation, comparative evaluations were made on the results of examinations in various countries regarding "direct disposal." Examinations have also been made as to whether there is a significant merit or demerit in direct disposal and plutonium recycling, and whether it is possible to generally apply the direct disposal method adopted in overseas countries to Japan. The investigation has revealed that there are factors such as techniques, energy, resources, economy, environment, institutions, safety, etc., which influence the spent fuel disposal policy. The five countries including the United States and Sweden, which have clearly taken up the direct disposal policy have so by laying importance on different factors according to the situations of the respective countries. Further, the comparative evaluation concerning the economy, safety, etc. has shown small difference between direct disposal and plutonium recycling and neither has any significant merit or demerit. Further, regarding the disposal concept, there are great differences according to the actual states of various countries; hence it is considered that Japan should carry out comparative evaluation of direct ...
Ishitani, Kazuki; Shibata, Masahiro; Ebashi, Takeshi; Wakasugi, Keiichiro; Makino, Hitoshi; Ebina, Takanori*
no journal, ,
There are a variety of spent fuels on reactor types, fuel types, burnup, and cooling periods, in Japan. On the direct disposal study, to set model inventories for design and performance assessment, we have to categorize many kinds of spent fuels considering with its characteristics and volumes. Spent fuels volume estimation has been performed based on model calculation, and then, it was discussed about characteristic grasp of fuels and view point of categorization to set model inventories.
Suda, Kazunori; Kokaji, Lisa; Tazaki, Makiko; Tamai, Hiroshi; Kuno, Yusuke*
no journal, ,
no abstracts in English
and spent fuel; A ReviewKitamura, Akira; Akahori, Kuniaki*
no journal, ,
Since dissolution rate of UO matrices will be depend on carbonate concentration due to promoting oxidative dissolution of spent nuclear fuel by formation of carbonate complexes of uranium(VI), effect of carbonate concentration on dissolution rate of UO and spent nuclear fuel has been reviewed. It is found that a systematic study on dissolution rate of UO and/or spent fuel as a function of carbonate concentration is recommended.
Suda, Kazunori; Tazaki, Makiko; Shimizu, Ryo; Kokaji, Lisa; Tamai, Hiroshi
no journal, ,
The spent fuel of the plutonium burner reactors from nuclear security perspective is considered in accord with previous discussion of regulatory body on physical protection for low-level radioactive waste including plutonium.
Suyama, Kenya; Akie, Hiroshi; Kataoka, Masaharu*; Yamamoto, Kento*
no journal, ,
no abstracts in English
Akie, Hiroshi; Kataoka, Masaharu*; Suyama, Kenya
no journal, ,
no abstracts in English
irradiationYukawa, Takuji*; Inoue, Hiroyuki*; Kojima, Takao*; Tachikawa, Hirokazu*; Taniguchi, Naoki
no journal, ,
no abstracts in English
