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JAEA Reports

Analysis of the radioactivity concentrations in low-level radioactive waste generated from JRR-2, JRR-3 and hot laboratory facilities

Tobita, Minoru*; Haraga, Tomoko; Sasaki, Takayuki*; Seki, Kotaro*; Omori, Hiroyuki*; Kochiyama, Mami; Shimomura, Yusuke; Ishimori, Kenichiro; Kameo, Yutaka

JAEA-Data/Code 2019-016, 72 Pages, 2020/02

JAEA-Data-Code-2019-016.pdf:2.67MB

In the future, radioactive wastes which generated from research and testing reactors in Japan Atomic Energy Agency are planning to be buried for the near surface disposal. Therefore, it is required to establish the method to evaluate the radioactivity concentrations of radioactive wastes by the time it starts disposal. In order to contribute to this work, we collected and analyzed the samples generated from JRR-2, JRR-3 and Hot laboratory facilities. In this report, we summarized the radioactivity concentrations of 25 radionuclides ($$^{3}$$H, $$^{14}$$C, $$^{36}$$Cl, $$^{60}$$Co, $$^{63}$$Ni, $$^{90}$$Sr, $$^{94}$$Nb, $$^{93}$$Mo, $$^{99}$$Tc, $$^{108m}$$Ag, $$^{126}$$Sn, $$^{129}$$I, $$^{137}$$Cs, $$^{152}$$Eu, $$^{154}$$Eu, $$^{233}$$U, $$^{234}$$U, $$^{238}$$U, $$^{238}$$Pu, $$^{239}$$Pu, $$^{240}$$Pu, $$^{241}$$Pu, $$^{241}$$Am, $$^{243}$$Am, $$^{244}$$Cm) which were obtained from radiochemical analysis of those samples.

JAEA Reports

Evaluation report of research and development on "Geological Disposal of High-level Radioactive Waste" (Interim report)

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.

Journal Articles

Research on activation assessment of a reactor structural materials for decommissioning

Seki, Misaki; Ishikawa, Koji*; Nagata, Hiroshi; Otsuka, Kaoru; Omori, Takazumi; Hanakawa, Hiroki; Ide, Hiroshi; Tsuchiya, Kunihiko; Sano, Tadafumi*; Fujihara, Yasuyuki*; et al.

KURNS Progress Report 2018, P. 257, 2019/08

no abstracts in English

JAEA Reports

Study on the evaluation method to determine the radioactivity concentration in radioactive waste generated from the dismantling of research reactors

Murakami, Masashi; Hoshino, Yuzuru; Nakatani, Takayoshi; Sugaya, Toshikatsu; Fukumura, Nobuo*; Sanda, Toshio*; Sakai, Akihiro

JAEA-Technology 2019-003, 50 Pages, 2019/06

JAEA-Technology-2019-003.pdf:4.42MB

Toward the establishment of a common approach to determine the radioactivity concentrations in dismantling wastes arising from research reactors, radionuclide concentrations in the reactor structure materials of aluminum, carbon steel, shield concrete, and graphite of TRIGA Mark II reactor at Rikkyo University, Japan, were evaluated with both radiochemical analysis and theoretical calculation. The measured nuclides by the radiochemical analysis were $$^{3}$$H, $$^{60}$$Co, and $$^{63}$$Ni in aluminum, $$^{3}$$H, $$^{60}$$Co, $$^{63}$$Ni, and $$^{152}$$Eu in carbon steel, $$^{3}$$H, $$^{60}$$Co, and $$^{152}$$Eu in shield concrete, and $$^{3}$$H, $$^{14}$$C, $$^{60}$$Co, $$^{63}$$Ni, and $$^{152}$$Eu in graphite. Neutron-flux distributions and neutron-induced activities were computed with DORT and ORIGEN-ARP codes, respectively. Using the results of material composition analysis, radioactivity concentrations were conservatively predicted with good accuracy except for graphite material.

Journal Articles

Risk communication at Horonobe Underground Research Center, using the Public Information House and Underground Research Laboratory

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.

Journal Articles

Effects of trust and procedural fairness on public acceptance of siting a repository for high-level radioactive waste

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.

Journal Articles

Importance of root uptake of $$^{14}$$CO$$_{2}$$ on $$^{14}$$C transfer to plants impacted by below-ground $$^{14}$$CH$$_{4}$$ release

Ota, Masakazu; Tanaka, Taku*

Journal of Environmental Radioactivity, 201, p.5 - 18, 2019/05

 Times Cited Count:2 Percentile:37.68(Environmental Sciences)

$$^{14}$$CH$$_{4}$$ released from deep underground radioactive waste disposal facilities can be a belowground source of $$^{14}$$CO$$_{2}$$ owing to microbial oxidation of $$^{14}$$CH$$_{4}$$ to $$^{14}$$CO$$_{2}$$ in soils. Environmental $$^{14}$$C models assume that the transfer of $$^{14}$$CO$$_{2}$$ from soil to plant occurs via foliar uptake of $$^{14}$$CO$$_{2}$$. Nevertheless, the importance of $$^{14}$$CO$$_{2}$$ root uptake is not well understood. In the present study, belowground transport and oxidation of $$^{14}$$CH$$_{4}$$ were modeled and incorporated into an existing land surface $$^{14}$$CO$$_{2}$$ model (SOLVEG-II) to assess the importance of root uptake on $$^{14}$$CO$$_{2}$$ transfer to plants. Performance of the model in calculating the belowground dynamics of $$^{14}$$CH$$_{4}$$ was validated by simulating a field experiment of $$^{13}$$CH$$_{4}$$ injection into subsoil. The model was then applied to $$^{14}$$C transfer in a hypothetical ecosystem impacted by continuous $$^{14}$$CH$$_{4}$$ input from the water table (bottom of one-meter thick soil). In a shallowly rooted ecosystem with rooting depth of 11 cm, foliar uptake of $$^{14}$$CO$$_{2}$$ was significant, accounting for 80% of the $$^{14}$$C accumulation in the leaves. In a deeply rooted ecosystem (rooting depth of 97 cm), where the root penetrated to depths close to the water-table, more than half (63%) the $$^{14}$$C accumulated in the leaves was transferred by the root uptake. We found that $$^{14}$$CO$$_{2}$$ root uptake in this ecosystem depended on the distribution of methane oxidation in the soil; all $$^{14}$$C accumulated in the leaves was transferred by the root uptake when methane oxidation occurred at considerable depths (e-folding depths of 20 cm, or 80 cm). These results indicate that $$^{14}$$CO$$_{2}$$ root uptake contributes significantly to $$^{14}$$CO$$_{2}$$ transfer to plants if $$^{14}$$CH$$_{4}$$ oxidation occurs at great depths and roots penetrate deeply into the soil.

JAEA Reports

Study on the basic system of the common non-destructive radioactivity measuring equipment for disposal of radioactive wastes generated from research, industrial and medical facilities

Izumo, Sari; Hayashi, Hirokazu; Nakata, Hisakazu; Amazawa, Hiroya; Motoyama, Mitsushi*; Sakai, Akihiro

JAEA-Technology 2018-018, 39 Pages, 2019/03

JAEA-Technology-2018-018.pdf:2.8MB

JAEA has planed the near surface disposal of LLW generated from research, industrial, and medical facilities. Maximum radioactivity concentration of each waste and total radioactivity of disposed wastes are needed to be less than the permitted values in the license of disposal facility. Thus, it is important not to evaluate the radioactivity of each waste in unduly conservative ways so as to dispose of the total amount of the waste that is originally planned. Accordingly, the detection limit is required to be as low as the clearance level for the very low level radioactive waste planned to be disposed of trench-type. In this report, the feasibility of the non-destructive assay method is studied by model calculations for gamma emitters. It is confirmed that the detection limit less than the clearance level can be achieved as regards the box type metal container that is difficult to measure. This report summarizes the requirements for the non-destructive measuring equipment.

JAEA Reports

Biosphere assessment methodology commonly applicable to varouis disposal concepts

Kato, Tomoko; Fukaya, Yukiko*; Sugiyama, Takeshi*; Nakai, Kunihiro*; Oda, Chie; Oi, Takao

JAEA-Data/Code 2019-002, 162 Pages, 2019/03

JAEA-Data-Code-2019-002.pdf:2.78MB

The radioactive waste generated from Fukushima Daiichi Nuclear Power Plant (FDNPP) accident have features such as wide range of contamination level (from low to high) and huge amount etc. It would be necessary for the waste from the FDNPP accident to construct suitable disposal concept and dispose safely and reasonably. To develop suitable disposal concepts for the waste from the FDNPP accident, applicability of the present disposal concepts (deep geological disposal, sub-surface disposal, near-surface disposal (trench type and concrete pit type), etc) is being discussed. For such disucssion it would be expected to be able to use common scenarios, models and parameter sets for various disposal concepts. Therefore, as a preliminary study to standardize such scenarios, models and parameter sets, a standardized biosphere model and parameter set which are applicable to the biospohere assessment for various disposal concepts were developed as an example refering to the existing biosphere models, parameters defined for present disposal concepts and latest findings. And, a set of flux-to-dose conversion factors calculated with the standardized biosphere model and parameter set was also demonstrated.

Journal Articles

Decision-making process on selection of management policy for high-level radioactive waste; As an example of Switzerland and United Kingdom

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.

Journal Articles

Decision-making process on site selection for the deep geological repository of high-level radioactive waste; As an example of Switzerland and United Kingdom

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.

JAEA Reports

Report on cause investigation and countermeasure of leakage trace from the drum

Shimomura, Yusuke; Sato, Takuya; Fukui, Yasutaka; Kudo, Kenji; Yoshioka, Tatsuji

JAEA-Review 2018-023, 220 Pages, 2019/01

JAEA-Review-2018-023.pdf:15.6MB

On September 11, 2015, leaky traces of bituminized wastes were confirmed from four drums filled with bituminization in waste packages storage yard (II) of waste management facility in Oarai Research and Development Center. Moreover, even after the subsequent investigation, a leakage trace was found from one bituminous drum on November 10, 2015. Furthermore, on December 2, 2015, there was no a leakage trace in one bituminous drum, however the upper lid was found to be intensely corroded. To investigate the causes and the countermeasures for leakages of bituminized wastes from the drums, we have set up a Work Group to investigate the causes and the countermeasures to leakage traces from the drums. This report is based on "Report on Cause Investigation and Countermeasure of Leakage Trace from the Drum" summarized by this working group, the report was reconstructed including the contents clarified in the subsequent document investigation.

Journal Articles

A Spectroscopic technique for analysis developed in the field of unclear energy

Kusaka, Ryoji

Bunko Kenkyu, 67(6), p.239 - 240, 2018/12

A spectroscopic technique for analysis developed by collaboration between Japan Atomic Energy Agency (JAEA) and Quantum and Radiological Science and Technology (QST) is discussed for readers outside the field of nuclear energy. This paper introduces a quantitative analysis for $$^{107}$$Pd radioisotope contained in a spent nuclear fuel by using laser-induced photoreduction and inductively coupled plasma mass spectrometry (ICP-MS). The importance and problems of quantitative analysis for radioisotopes in spent nuclear fuels are described, and the principle, advantages, and future applications of the spectroscopic technique are discussed.

Journal Articles

Can the decision way by the "veil of ignorance" promote public acceptance?; A Hypothetical scenario survey about selecting a candidate site for geological disposal of high level radioactive waste in Japan

Onuma, Susumu*; Hirose, Yukio*; Osawa, Hideaki; Otomo, Shoji*; Yokoyama, Miki*

Nippon 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.

Journal Articles

Development of cement based encapsulation for low radioactive liquid waste in Tokai Reprocessing Plant

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).

Journal Articles

Diffusion behavior of D$$_{2}$$O in Fe$$_{3}$$O$$_{4}$$ film on Fe formed in an NaOH solution containing oxidants

Haruna, 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 Fe$$_{3}$$O$$_{4}$$ 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 D$$_{2}$$O in the Fe$$_{3}$$O$$_{4}$$ film at room temperature. The results were obtained as follows. It was confirmed that Fe$$_{3}$$O$$_{4}$$ 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. D$$_{2}$$O 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 D$$_{2}$$O 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 D$$_{2}$$O constant. The constant amount of D$$_{2}$$O 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 D$$_{2}$$O absorbed into the film was analyzed on the basis of Fick's law for diffusion, and diffusion coefficients of D$$_{2}$$O were obtained to be 5.1$$times$$10$$^{-15}$$ cm$$^{2}$$ s$$^{-1}$$ and 9.9$$times$$10$$^{-15}$$ cm$$^{2}$$ s$$^{-1}$$ for the films formed for 1.2 and 3.6 ks, respectively. Therefore it was estimated that the diffusion coefficient of the Fe$$_{3}$$O$$_{4}$$ film was in the region from 5.1$$times$$10$$^{-15}$$ cm$$^{2}$$ s$$^{-1}$$ to 9.9$$times$$10$$^{-15}$$ cm$$^{2}$$ s$$^{-1}$$.

JAEA Reports

Horonobe Underground Research Laboratory Project; Investigation program for the 2018 fiscal year

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).

JAEA Reports

Study on the evaluation methodology of the radioactivity concentration in low-level radioactive wastes generated from JRR-2 & JRR-3

Hayashi, Hirokazu; Izumo, Sari; Nakata, Hisakazu; Amazawa, Hiroya; Sakai, Akihiro

JAEA-Technology 2018-001, 66 Pages, 2018/06

JAEA-Technology-2018-001.pdf:4.12MB
JAEA-Technology-2018-001(errata).pdf:0.54MB

It is necessary to establish evaluation methodology of radioactivity concentrations of each radionuclide in waste packages for operation of the Near-surface Trench disposal and Sub-surface Pit disposal facility in near future, which has been preparing for low-level radioactive wastes generated from research facilities in JAEA. The radionuclides containing in waste packages generated from both JRR-2 and JRR-3, which are H-3, C-14, Cl-36, Co-60, Ni-63, Sr-90, Nb-94, Tc-99, Ag-108m, I-129, Cs-137, Eu-152, Eu-154, U-234, U-238, Pu-239+240, Pu-238+Am-241, Cm-243+244, were evaluated their density based on radiochemical analysis data, and the Evaluation Methodology of the Radioactivity Concentration such as Scaling Factor method and mean activity concentration method was studied in this report.

Journal Articles

Decontamination of radioactive concrete waste and reuse of aggregate using pulsed power technology

Sakamoto, Hiroyuki*; Akagi, Yosuke*; Yamada, Kazuo*; Tachi, Yukio; Fukuda, Daisuke*; Ishimatsu, Koichi*; Matsuda, Mikiya*; Saito, Nozomi*; Uemura, Jitsuya*; Namihira, Takao*; et al.

Nippon Genshiryoku Gakkai Wabun Rombunshi, 17(2), p.57 - 66, 2018/05

Concrete debris contaminated with radioactive cesium and other nuclides have been generated from the accident in the Fukushima Dai-ichi Nuclear Power Plant and there will be generated due to the decommissioning of nuclear power plants in the future. Although conventional decontamination techniques are effective for flat concrete surfaces such as floors and walls, it is not clear what techniques to apply for decontaminating radioactive concrete debris. In this study, focusing on a pulsed power discharge technique, fundamental experimental works were carried out. Decontamination of concrete by applying the aggregate recycling technique using the pulsed power discharge technique was evaluated by measuring radioactivity of aggregate and sludge separated from the contaminated concrete. The results suggest that the separation into aggregate and sludge of the contaminated concrete debris could achieve decontamination and volume reduction of the radioactive concrete debris.

Journal Articles

Temporal trend in excavation disturbed zone around a modeled disposal pit in Horonobe Underground Research Laboratory

Aoyagi, Kazuhei; Miyara, Nobukatsu; Ishii, Eiichi; Matsuzaki, Yoshiteru

Shigen, Sozai Koenshu (Internet), 5(1), 7 Pages, 2018/03

no abstracts in English

873 (Records 1-20 displayed on this page)