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Journal Articles

Development of hydrogen oxidation reaction catalysts to overcome CO poisoning and elucidation of reaction mechanism

Inagawa, Kohei*; Matsumura, Daiju; Taniguchi, Masashi*; Uegaki, Shinya*; Nakayama, Tomohito*; Urano, Junnosuke*; Aotani, Takuro*; Tanaka, Hirohisa*

Journal of Physical Chemistry C, 127(24), p.11542 - 11549, 2023/06

JAEA Reports

Decommissioning of uranium handling facility for development of nuclear fuel manufacturing equipment

Kageyama, Tomio; Denuma, Akio; Koizumi, Jin*; Odakura, Manabu*; Haginoya, Masahiro*; Isaka, Shinichi*; Kadowaki, Hiroyuki*; Kobayashi, Shingo*; Morimoto, Taisei*; Kato, Yoshiaki*; et al.

JAEA-Technology 2022-033, 130 Pages, 2023/03

JAEA-Technology-2022-033.pdf:9.87MB

Uranium handling facility for development of nuclear fuel manufacturing equipment (Mockup room) was constructed in 1972. The Mockup room has a weak seismic resistance and is deteriorating with age. Also, the original purpose with this facility have been achieved and there are no new development plans using this facility. Therefore, interior equipment installed in this facility had been dismantled and removed since March 2019. After that, the Mockup room was inspected for contamination, and then controlled area in the Mockup room was cancelled on March 29th 2022. A total of 6,549 workers (not including security witnesses) were required for this work. The amount of non-radioactive waste generated by this work was 31,300 kg. The amount of radioactive waste generated by this work was 3,734 kg of combustible waste (103 drums), 4,393 kg of flame resistance waste (61 drums), 37,790 kg of non-combustible waste (124 drums, 19 containers). This report describes about the dismantling and removing the interior equipment in the Mockup room, the amount of waste generated by this work, and procedure for cancellation the controlled area in the facility.

JAEA Reports

Decommissioning of the Plutonium Research Building No.1 (Plan and Present Status)

Komuro, Michiyasu; Kanazawa, Hiroyuki; Kokusen, Junya; Shimizu, Osamu; Honda, Junichi; Harada, Katsuya; Otobe, Haruyoshi; Nakada, Masami; Inagawa, Jun

JAEA-Technology 2021-042, 197 Pages, 2022/03

JAEA-Technology-2021-042.pdf:16.87MB

Plutonium Research Building No.1 was constructed in 1960 for the purpose of establishing plutonium handling technology and studying its basic physical properties. Radiochemical research, physicochemical research and analytical chemistry regarding solutions and solid plutonium compounds had been doing for the research program in Japan Atomic Energy Agency (JAEA). In 1964, the laboratory building was expanded and started the researching plutonium-uranium mixed fuel and reprocessing of plutonium-based fuel, playing an advanced role in plutonium-related research in Japan. Since then, the research target has been expanded to include transplutonium elements, and it has functioned as a basic research facility for actinides. The laboratory is constructed by concrete structure and it has the second floor, equipped with 15 glove boxes and 4 chemical hoods. Plutonium Research Building No.1 was decided as one of the facilities to be decommissioned by Japan Atomic Energy Agency Reform Plan in September 2014. So far, the contamination survey of the radioactive materials in the controlled area, the decontamination of glove boxes, and the consideration of the equipment dismantling procedure have been performed as planned. The radioisotope and nuclear fuel materials used in the facility have been transfer to the other facilities in JAEA. The decommissioning of the facility is proceeding with the goal of completing by decommissioning the radiation controlled area in 2026. In this report, the details of the decommissioning plan and the past achievements are reported with the several data.

JAEA Reports

Carrying-out of whole nuclear fuel materials in Plutonium Research Building No.1

Inagawa, Jun; Kitatsuji, Yoshihiro; Otobe, Haruyoshi; Nakada, Masami; Takano, Masahide; Akie, Hiroshi; Shimizu, Osamu; Komuro, Michiyasu; Oura, Hirofumi*; Nagai, Isao*; et al.

JAEA-Technology 2021-001, 144 Pages, 2021/08

JAEA-Technology-2021-001.pdf:12.98MB

Plutonium Research Building No.1 (Pu1) was qualified as a facility to decommission, and preparatory operations for decommission were worked by the research groups users and the facility managers of Pu1. The operation of transportation of whole nuclear materials in Pu1 to Back-end Cycle Key Element Research Facility (BECKY) completed at Dec. 2020. In the operation included evaluation of criticality safety for changing permission of the license for use nuclear fuel materials in BECKY, cask of the transportation, the registration request of the cask at the institute, the test transportation, formulation of plan for whole nuclear materials transportation, and the main transportation. This report circumstantially shows all of those process to help prospective decommission.

JAEA Reports

Stabilization of uranium hexafluoride by hydrolysis method for decommissioning of safeguard laboratory facility

Inagawa, Jun; Hotoku, Shinobu; Oda, Tetsuzo; Aoyagi, Noboru; Magara, Masaaki

JAEA-Technology 2014-007, 48 Pages, 2014/03

JAEA-Technology-2014-007.pdf:5.76MB

In safeguard laboratory (SGL) facility of Nuclear Science Research Institute of JAEA, uranium hexafluoride (UF$$_{6}$$) of enriched uranium of various enrichment was used for research and development of a spectrometric method for the determination of the enrichment of uranium in April 1983 through March 1993. After completion of this R&D, the UF$$_{6}$$ has been stored in SGL facility. It was decided that the UF$$_{6}$$ is carried to out of the facility, because the SGL facility will be decommissioning until March 2015. To transport and store in safety after transportation, it is necessary that the UF$$_{6}$$ should be converted to stable chemical form. Hydrolysis of UF$$_{6}$$ to uranyl fluoride (UO$$_{2}$$F$$_{2}$$) and evaporation to solid state were selected for the stabilization method. The equipment for hydrolysis and evaporation was installed in the SGL facility. Stabilization was operated in this equipment, and all of the UF$$_{6}$$ in the SGL facility was converted to UO$$_{2}$$F$$_{2}$$ solid state in October 2012 through August 2013. In this report, results of examination and operation for stabilization of UF$$_{6}$$ were reported.

Journal Articles

Isotope dilution inductively coupled plasma mass spectrometry for determination of $$^{126}$$Sn content in spent nuclear fuel sample

Asai, Shiho; Toshimitsu, Masaaki; Hanzawa, Yukiko; Suzuki, Hideya; Shinohara, Nobuo; Inagawa, Jun; Okumura, Keisuke; Hotoku, Shinobu; Kimura, Takaumi; Suzuki, Kensuke*; et al.

Journal of Nuclear Science and Technology, 50(6), p.556 - 562, 2013/06

 Times Cited Count:11 Percentile:64.36(Nuclear Science & Technology)

The $$^{126}$$Sn content in a spent nuclear fuel solution was determined by ICP-MS for its inventory estimation in high-level radioactive waste. An irradiated UO$$_{2}$$ fuel was used as a sample to evaluate the reliability of the methodology. Prior to the measurement, Sn was separated from $$^{126}$$Te, which causes major isobaric interference in the determination of $$^{126}$$Sn content, along with highly radioactive coexisting elements using an anion-exchange column. The absence of counts attributed to Te in the Sn-containing effluent indicates that Te was completely removed. After washing, Sn retained on the column was readily eluted with 1 M HNO$$_{3}$$. The isotope ratios of Sn were successfully determined and showed good agreement with those obtained through ORIGEN2 calculations. The results reported in this paper are the first experimental values of $$^{126}$$Sn content in the spent nuclear fuel solution originating in spent nuclear fuel irradiated at a nuclear power plant in Japan.

Journal Articles

Application of a continuous heating method using thermal ionization mass spectrometry to measure isotope ratios of plutonium and uranium in trace amounts of uranium-plutonium mixture sample

Kokubu, Yoko; Suzuki, Daisuke; Lee, C. G.; Inagawa, Jun; Magara, Masaaki; Kimura, Takaumi

International Journal of Mass Spectrometry, 310, p.52 - 56, 2012/01

 Times Cited Count:20 Percentile:72.82(Physics, Atomic, Molecular & Chemical)

A method for measuring isotope ratios of Pu and U in Pu or Pu/U mixture samples was developed by using a continuous heating method of thermal ionization mass spectrometry (TIMS). In this method, temperature of an evaporation filament is increased sequentially. This leads to measure the ratios of Pu and U at different temperature in which each element is evaporated efficiently. In Pu/U mixture samples with pg-level masses and 0.01-10 Pu/U ratios, isotope ratios of $$^{240}$$Pu/$$^{239}$$Pu and $$^{235}$$U/$$^{238}$$U were measured simultaneously without chemical separation of samples. The relative standard deviation of the isotope ratios of $$^{240}$$Pu/$$^{239}$$Pu and $$^{235}$$U/$$^{238}$$U in the sample containing each 1 pg of Pu and U were better than 2% and 4%, respectively. Moreover, $$^{238}$$Pu/$$^{239}$$Pu ratios were obtained. The results suggest that the continuous heating method of TIMS will be effective tool as a method for measuring isotope ratios in the Pu/U mixture samples.

Journal Articles

Simple cation-exchange separation for ICP-MS measurement of $$^{79}$$Se in spent nuclear fuel sample

Asai, Shiho; Hanzawa, Yukiko; Suzuki, Hideya; Toshimitsu, Masaaki; Okumura, Keisuke; Shinohara, Nobuo; Kimura, Takaumi; Inagawa, Jun; Suzuki, Kensuke*; Kaneko, Satoru*

Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 5 Pages, 2011/12

Journal Articles

New ORIGEN2 libraries based on JENDL-4.0 and their validation for long-lived fission products by post irradiation examination analyses of LWR spent fuels

Kojima, Kensuke; Okumura, Keisuke; Asai, Shiho; Hanzawa, Yukiko; Okamoto, Tsutomu; Toshimitsu, Masaaki; Inagawa, Jun; Kimura, Takaumi; Kaneko, Satoru*; Suzuki, Kensuke*

Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 5 Pages, 2011/12

Accurate inventory estimation of long-lived fission products (LLFPs) in LWR spent fuels is important for the quality management and for long-term safety assessment of high-level radioactive vitrified wastes. In Japan, ORIGEN2 has been widely used to estimate the fuel compositions. However, equipped library data in the original ORIGEN2 are old and are not validated enough for LLFPs, such as $$^{79}$$Se, $$^{99}$$Tc, $$^{126}$$Sn and $$^{135}$$Cs, because available post irradiation examination (PIE) data are limited for these nuclides, which have difficulties in radiochemical analyses. For more accurate the estimation, new ORIGEN2 libraries are developed from the latest nuclear data library JENDL-4.0 for cross sections and fission yields, and from other libraries for half-lives, and so on. The new libraries are validated by PIE analyses of the sample fuels irradiated in Cooper, Calvert-Cliffs-1, H. B. Robinson-2, and Ohi-1. As a result, it was found that the new library gives good results for the estimation.

Journal Articles

Experience on implementation of the Integrated Safeguards approach for the MOX facility from the operator's point of view

Nomi, Takayoshi; Nagatani, Taketeru; Ninagawa, Junichi; Nakajima, Shinji; Maruyama, Hajime; Asano, Takashi; Fujiwara, Shigeo

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-32-Kai Nenji Taikai Rombunshu (Internet), 8 Pages, 2011/11

The IS approach for the JNC-1 site was implemented in August 2008, and this was the first experience in the world. This IS approach aimed not only to improve efficiency and effectiveness of safeguards but also to reduce burden of the plant operation by improvement of efficiency of the inspection activity. It was planned to review effectiveness of this new approach after three years from implementation. And JAEA also evaluated effects by application of the IS approach for two MOX fuel facilities in the JNC-1 site based on the three years experiences from the operator's view point. As the result of evaluation, it was confirmed that there were some difference of benefits by application of the IS approach depending on features of the facility, automation level of equipment and advance level of safeguards systems.

Journal Articles

Analyses of assay data of LWR spent nuclear fuels with a continuous-energy Monte Carlo code MVP and JENDL-4.0 for inventory estimation of $$^{79}$$Se, $$^{99}$$Tc, $$^{126}$$Sn and $$^{135}$$Cs

Okumura, Keisuke; Asai, Shiho; Hanzawa, Yukiko; Suzuki, Hideya; Toshimitsu, Masaaki; Inagawa, Jun; Okamoto, Tsutomu; Shinohara, Nobuo; Kaneko, Satoru*; Suzuki, Kensuke*

Progress in Nuclear Science and Technology (Internet), 2, p.369 - 374, 2011/10

For accurate inventory estimation of long-lived fission products in LWR spent fuels, a new burn-up chain model and decay data based on the latest nuclear data such as JENDL-4.0 was developed. MVP-BURN with the latest nuclear data was applied to several post irradiation examinations including inventory measurements of $$^{79}$$Se, $$^{99}$$Tc, $$^{126}$$Sn and $$^{135}$$Cs. One of them is a new measurement by JAEA. From the PIE analyses, it is found that the new PIE data obtained by JAEA is consistent with the other PIE data by different laboratory with different techniques. It is also confirmed that the present calculation results show good agreements with experimental ones within about 10% for productions of $$^{79}$$Se and $$^{135}$$Cs. In contrast, amounts of $$^{99}$$Tc and $$^{126}$$Sn are overestimated by about 50%. These discrepancies are likely due to the effect of insoluble residue produced during sample dissolution and/or errors of fission yields in the analyses.

Journal Articles

Validation of correlations between Nd isotopes and difficult-to-measure nuclides predicted with burn-up calculation code by post irradiation examination

Asai, Shiho; Okumura, Keisuke; Hanzawa, Yukiko; Suzuki, Hideya; Toshimitsu, Masaaki; Inagawa, Jun; Kimura, Takaumi; Kaneko, Satoru*; Suzuki, Kensuke*

Proceedings of 14th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2011) (CD-ROM), p.1437 - 1442, 2011/09

Journal Articles

Computational study for inventory estimation of Se-79, Tc-99, Sn-126, and Cs-135 in high-level radioactive wastes from spent nuclear fuels of light water reactors

Okumura, Keisuke; Asai, Shiho; Hanzawa, Yukiko; Okamoto, Tsutomu; Suzuki, Hideya; Toshimitsu, Masaaki; Inagawa, Jun; Kimura, Takaumi; Suzuki, Kensuke*; Kaneko, Satoru*

Proceedings of 14th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2011) (CD-ROM), p.1443 - 1450, 2011/09

Inventory estimation of long-lived fission products (LLFPs) in high-level radioactive wastes (HLW) from spent nuclear fuels of light water reactors is important for a safety assessment of their disposal. In order to develop an inventory estimation method of difficult-to-measure LLFPs (Se-79, Tc-99, Sn-126, and Cs-135), a parametric study was carried out by using a sophisticated burnup calculation code and data. In the parametric study, fuel specifications and irradiation conditions are changed in the conceivable range. The considered parameters are fuel assembly types (PWR / BWR), U-235 enrichment, moderator temperature, void fraction, power density, and so on. From the calculated results, we clarify the burnup characteristics of the target LLFPs and their possible ranges of generations. Finally, candidates of the key nuclide are proposed for the scaling factor method of HLW.

Journal Articles

Evaluation of application effect of the integrated safeguards approach for MOX fuel fabrication facilities from the operator's viewpoint

Ninagawa, Junichi; Asano, Takashi; Nagatani, Taketeru; Nakajima, Shinji; Nomi, Takayoshi; Fujiwara, Shigeo

Proceedings of INMM 52nd Annual Meeting (CD-ROM), 8 Pages, 2011/07

Japan was transferred to the Integrated Safeguards (IS) scheme in September 2004. The IS approach for JNC-1 site, including PFPF, was developed to improve the efficiency of safeguards while maintaining the effectiveness and has been implemented since August 2008. JAEA has evaluated the validity of the IS approach for PFPF based on the historical performance over about three-year period. As the result of evaluation, JAEA confirmed the improvement of efficiency of inspection activities and the reduction of the impact of inspection activities on plant operation. On the other hand, the IAEA has also evaluated the validity of IS approach and considered to modify based on the result of its evaluation. In order to maintain or improve the validity of the IS approach, JAEA thinks that it will be necessary to work very closely and honestly with the inspectorate to address this modification process.

Journal Articles

Determination of $$^{79}$$Se and $$^{135}$$Cs in spent nuclear fuel for inventory estimation of high-level radioactive wastes

Asai, Shiho; Hanzawa, Yukiko; Okumura, Keisuke; Shinohara, Nobuo; Inagawa, Jun; Hotoku, Shinobu; Suzuki, Kensuke*; Kaneko, Satoru*

Journal of Nuclear Science and Technology, 48(5), p.851 - 854, 2011/05

 Times Cited Count:24 Percentile:85.78(Nuclear Science & Technology)

Journal Articles

QA/QC activities and estimation of uncertainty for ultra-trace analysis of uranium and plutonium in safeguards environmental samples

Usuda, Shigekazu*; Magara, Masaaki; Esaka, Fumitaka; Yasuda, Kenichiro; Kokubu, Yoko; Lee, C. G.; Miyamoto, Yutaka; Suzuki, Daisuke; Inagawa, Jun; Sakurai, Satoshi; et al.

Journal of Nuclear and Radiochemical Sciences, 11(2), p.A5 - A9, 2011/01

In the analysis of IAEA safeguards environmental samples, isotope ratios of ultra-trace amounts of uranium and plutonium in samples taken from nuclear facilities are determined to detect undeclared nuclear materials and activities. In order to keep and enhance the reliability of the measurement results, validation of analytical methods and estimation of measurement uncertainty in such ultra-trace analysis should be properly done in accordance with worldwide standards. In this paper, the current activities on achievement of QA/QC (quality assurance and quality control) and estimation of measurement uncertainty in the ultra-trace analysis at a clean chemistry laboratory (CLEAR) of JAEA are reported.

Journal Articles

Post irradiation examination analyses with a continuous-energy Monte Carlo code MVP for long-lived fission products in LWR spent fuels

Okumura, Keisuke; Asai, Shiho; Hanzawa, Yukiko; Suzuki, Hideya; Toshimitsu, Masaaki; Inagawa, Jun; Katakura, Junichi; Shinohara, Nobuo; Kaneko, Satoru*; Suzuki, Kensuke*

Proceedings of Joint International Conference of 7th Supercomputing in Nuclear Application and 3rd Monte Carlo (SNA + MC 2010) (USB Flash Drive), 5 Pages, 2010/10

For accurate inventory estimation of long-lived fission products in LWR spent fuels, a new burn-up chain model and decay data based on the latest nuclear data were developed for MVP-BURN. They were applied to three post irradiation examinations including inventory measurements of $$^{79}$$Se, $$^{99}$$Tc, $$^{126}$$Sn and $$^{135}$$Cs. One of them is new measurements performed by JAEA. From the PIE analyses, it is found that the new measurements by JAEA are consistent with the other PIE data obtained by different laboratory with different techniques. It is also confirmed that the present calculation results show good agreements with experimental ones for $$^{79}$$Se and $$^{135}$$Cs within about 10%. In contrast, amounts of $$^{99}$$Tc and $$^{126}$$Sn are overestimated by about up to 50%. These discrepancies are likely due to the effect of insoluble residue in the measurements and/or errors of fission yields in the analyses.

Journal Articles

Research and development on environmental radionuclides for nuclear non-proliferation at Japan Atomic Energy Agency

Usuda, Shigekazu; Shinohara, Nobuo; Sakurai, Satoshi; Magara, Masaaki; Miyamoto, Yutaka; Esaka, Fumitaka; Yasuda, Kenichiro; Kokubu, Yoko; Hirayama, Fumio; Lee, C. G.; et al.

KEK Proceedings 2007-16, p.13 - 22, 2008/02

For the purpose of controlling and monitoring radiations and radioactive materials emitted from nuclear facilities to the environment and also evaluating their effects, various R&D on environmental radioactivity has been carried out at Japan Atomic Energy Agency (JAEA). Especially, for the abolition of nuclear weapons and for peaceful uses nuclear energy, ultra-trace analysis of environmental samples for safeguards and ultra-high sensitive monitoring of radionuclides for the CTBT verification, which have been scheduled in the middle of 1990s, have been promotted under the auspices of the Japanese Government at JAERI, the former of JAEA. In this presentation, the outline of R&D on environmental radioactivity for nuclear non-proliferation is introduced. In addition, applications of the developed techniques and future perspectives will be discussed.

Journal Articles

Development of analytical technique for safeguards environmental samples at JAEA; Current status and development of analytical method for isotope ratios of plutonium particles

Magara, Masaaki; Usuda, Shigekazu; Sakurai, Satoshi; Shinohara, Nobuo; Esaka, Fumitaka; Kokubu, Yoko; Suzuki, Daisuke; Yasuda, Kenichiro; Lee, C. G.; Inagawa, Jun; et al.

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-29-Kai Nenji Taikai Rombunshu (CD-ROM), 6 Pages, 2008/00

JAEA has been developing, under the auspices of the Ministry of Education, Culture, Sports, Science and Technology of Japan, analytical techniques for ultra-trace amounts of nuclear materials in the environmental samples in order to contribute to the strengthened safeguards system. In January 2003, JAEA was qualified as a member of the IAEA network analytical laboratories (NWAL) for environmental sample analysis. Since then, JAEA has conducted the analysis of domestic and the IAEA samples. Two techniques, bulk and particle analyses, are available for the environmental samples and the latter method generally provides more detailed information about history of nuclear materials in a facility. However, isotope ratios of uranium are measured in the particle analysis at present and it is wished to develop analytical method for isotope ratios of plutonium in individual particles. We commence the development of the plutonium particle analysis and the consideration of age-dating for plutonium particles through the atomic ratio of Pu-241 and Am-241.

Journal Articles

Development of safeguards environmental sample analysis techniques at JAEA as a network laboratory of IAEA

Sakurai, Satoshi; Magara, Masaaki; Esaka, Fumitaka; Hirayama, Fumio; Lee, C. G.; Yasuda, Kenichiro; Inagawa, Jun; Suzuki, Daisuke; Iguchi, Kazunari; Kokubu, Yoko; et al.

STI/PUB/1298 (CD-ROM), p.791 - 799, 2007/08

no abstracts in English

62 (Records 1-20 displayed on this page)