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Journal Articles

Experiments of melt jet-breakup for agglomerated debris formation using a metallic melt

Iwasawa, Yuzuru; Sugiyama, Tomoyuki; Abe, Yutaka*

Nuclear Engineering and Design, 386, p.111575_1 - 111575_17, 2022/01

Journal Articles

Now is the time of fast reactor

Negishi, Hitoshi; Kamide, Hideki; Maeda, Seiichiro; Nakamura, Hirofumi; Abe, Tomoyuki

Nihon Genshiryoku Gakkai-Shi ATOMO$$Sigma$$, 62(8), p.438 - 441, 2020/08

Prototype Fast Breeder Reactor, Monju, was under decommission since April, 2018. It is the first time for Japan to make a sodium cooled reactor into decommission. It is significant work and will take 30 years. The Monju has provided wide spectrum and huge amount of findings and knowledge, e.g., design, R&D, manufacturing, construction, and operation up to 40% of full power over 50 years of development history. It is significant to utilize such findings and knowledge for the development and commercialization of a fast rector in Japan.

Journal Articles

Enhancement of element production by incomplete fusion reaction with weakly bound deuteron

Wang, H.*; Otsu, Hideaki*; Chiga, Nobuyuki*; Kawase, Shoichiro*; Takeuchi, Satoshi*; Sumikama, Toshiyuki*; Koyama, Shumpei*; Sakurai, Hiroyoshi*; Watanabe, Yukinobu*; Nakayama, Shinsuke; et al.

Communications Physics (Internet), 2(1), p.78_1 - 78_6, 2019/07

 Times Cited Count:5 Percentile:62.37(Physics, Multidisciplinary)

Searching for effective pathways for the production of proton- and neutron-rich isotopes through an optimal combination of reaction mechanism and energy is one of the main driving forces behind experimental and theoretical nuclear reaction studies as well as for practical applications in nuclear transmutation of radioactive waste. We report on a study on incomplete fusion induced by deuteron, which contains one proton and one neutron with a weak binding energy and is easily broken up. This reaction study was achieved by measuring directly the cross sections for both proton and deuteron for $$^{107}$$Pd at 50 MeV/u via inverse kinematics technique. The results provide direct experimental evidence for the onset of a cross-section enhancement at high energy, indicating the potential of incomplete fusion induced by loosely-bound nuclei for creating proton-rich isotopes and nuclear transmutation of radioactive waste.

Journal Articles

Formation of agglomerated debris in jet-breakup experiment using metallic melts

Iwasawa, Yuzuru; Sugiyama, Tomoyuki; Maruyama, Yu; Kaneko, Akiko*; Abe, Yutaka*

Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 6 Pages, 2019/05

Journal Articles

Current status of research for the accident of evaporation to dryness caused by boiling of reprocessed high level radioactive liquid waste

Tamaki, Hitoshi; Yoshida, Kazuo; Abe, Hitoshi; Sugiyama, Tomoyuki; Maruyama, Yu

Proceedings of Asian Symposium on Risk Assessment and Management 2017 (ASRAM 2017) (USB Flash Drive), 9 Pages, 2017/11

An accident of evaporation to dryness caused by boiling of high level radioactive liquid waste (HLLW) is postulated as one of severe accidents caused by the loss of cooling function at the fuel reprocessing plant. This accident can be divided into early boiling stage, late boiling stage and dry-out stage by characteristics of accident evolution. It is important to estimate the amount of fission product (FP) transport between the liquid and gas phases, and the amount of FP deposition on the walls in each stage in order to estimate the release amount of FP to the environment. Various research activities have been carried out for this issue. This paper reviews these activities and presents the recent activities at JAEA for development of simulation code for this type of accident.

Journal Articles

A New radiation hardened CMOS image sensor for nuclear plant

Watanabe, Takashi*; Takeuchi, Tomoaki; Ozawa, Osamu*; Komanome, Hirohisa*; Akahori, Tomoyuki*; Tsuchiya, Kunihiko

Proceedings of 2017 International Image Sensor Workshop (IISW 2017) (Internet), p.206 - 209, 2017/05

no abstracts in English

Journal Articles

Improvement of ex-vessel molten core behavior models for the JASMINE code

Matsumoto, Toshinori; Kawabe, Ryuhei; Sugiyama, Tomoyuki; Maruyama, Yu

Proceedings of 10th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-10) (USB Flash Drive), 9 Pages, 2016/11

During severe accident at nuclear power stations, molten core material jet could be discharged from the reactor pressure vessel into the water pool formed at the pedestal or cavity in the containment vessel. To improve the JASMINE code, The method for determining particle diameters which follow the Rosin-Rammler distribution was implemented. The jet breakup experiments, DEFOR-A conducted by KTH (Royal Institute of Technology, Sweden) were analyzed with the code. The influence of the experimental conditions, such as water subcooling, melt jet diameter and superheat were discussed. A crust layer formation model was also implemented in the code. The analyses using the model were carried out for the melt spreading experiments, PULiMS conducted by KTH. The spreading area was overestimated. Further improvement of the melt spreading model were discussed to close the gaps by introducing additional models such as heat conduction in the substrate materials, void formed inside the melt and so on.

Journal Articles

Development of the pump-integrated intermediate heat exchanger in advanced loop-type sodium-cooled fast reactor for demonstration

Amano, Katsunori; Enuma, Yasuhiro; Futagami, Satoshi; Inoue, Tomoyuki*; Watanabe, Sota*

Proceedings of 24th International Conference on Nuclear Engineering (ICONE-24) (DVD-ROM), 7 Pages, 2016/06

In the framework of GIF, SDC and SDG for the generation IV SFRs have been developed in the circumstance of worldwide deployment of SFRs. JAEA and MFBR have been investigating design study of an advanced loop-type SFR to satisfy SDC in the feasibility study of SDG for SFR. In this study, the ability of the pump/IHX in the advanced loop-type SFR for the safety measures has been evaluated. In addition to the safety measures, maintainability and reparability are taken into account in the advanced loop-type SFR design study. The pump/IHX has been modified to satisfy these requirements. This paper describes the modifications for the ability to withstand a severe earthquake, the reliability of the guard vessel in the primary coolant leak, and the reliability of expansion joints in a sodium-water reaction. The evaluations of thermal transient, structural vibration with pump rotation and wear-out of IHX tubes, that has been adversely effected by the modifications, were described as well.

JAEA Reports

Analysis of the radioactivity concentrations in low-level radioactive waste generated from JPDR facilities, 3

Yasuda, Mari; Tanaka, Kiwamu; Watanabe, Koichi; Hoshi, Akiko; Tsuji, Tomoyuki; Kameo, Yutaka

JAEA-Data/Code 2014-011, 59 Pages, 2014/08

JAEA-Data-Code-2014-011.pdf:16.84MB

Simple and rapid methods to evaluate the radioactivity concentrations are required to be established for the near surface disposal of radioactive wastes generated from research facilities at Japan Atomic Energy Agency. In order to establish the methods to evaluate the radioactivity concentrations of miscellaneous solid wastes generated from research and testing reactors, we collected and analyzed samples from miscellaneous solid wastes generated by the decommissioning of JPDR (Japan Power Demonstration Reactor). In the present paper, we summarized data about the radioactivity concentrations which accumulated by the analysis.

JAEA Reports

Analysis of the radioactivity concentrations in low-level radioactive waste generated from JPDR facilities, 2

Tanaka, Kiwamu; Yasuda, Mari; Watanabe, Koichi; Hoshi, Akiko; Tsuji, Tomoyuki; Higuchi, Hidekazu

JAEA-Data/Code 2013-008, 16 Pages, 2013/11

JAEA-Data-Code-2013-008.pdf:2.41MB

Simple and rapid methods to evaluate the radioactivity concentrations are required to be established for the near surface disposal of radioactive wastes generated from research facilities at Japan Atomic Energy Agency. In order to establish the methods to evaluate the radioactivity concentrations of miscellaneous solid wastes generated from research and testing reactors, we collected and analyzed samples from miscellaneous solid wastes generated by the decommissioning of JPDR (Japan Power Demonstration Reactor). In the present paper, we summarized data about the radioactivity concentrations which accumulated by the analysis.

Journal Articles

Oxygen potential analysis to evaluate irradiation behavior in MOX and MA-bearing MOX fuels

Kato, Masato; Abe, Tomoyuki

Journal of Energy and Power Engineering, 7(10), p.1865 - 1870, 2013/10

Journal Articles

Japanese FR deployment scenario study after the Fukushima accident

Ono, Kiyoshi; Shiotani, Hiroki; Ohtaki, Akira; Mukaida, Kyoko; Abe, Tomoyuki

Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Safe Technologies and Sustainable Scenarios (FR-13) (USB Flash Drive), 10 Pages, 2013/03

In parallel to the mid-term analyses by the AEC after the Fukushima-accident, JAEA implemented the long-term scenario analyses for the nuclear fuel cycle options including FR cycle deployment. As a result, it was revealed that FR cycle deployment brings great benefits to reduction of uranium demand, spent fuel storage, radioactive waste generation, and Pu stockpiles in addition to potential hazard of HLW in "20 GWe constant after 2030" case. Meanwhile, it was also revealed the benefits of reduction of radioactive waste generation and Pu stockpiles in "Gradual decrease from 20 GWe after 2030" case.

JAEA Reports

Analysis of the radioactivity concentrations in low-level radioactive waste generated from JPDR facilities

Hoshi, Akiko; Tsuji, Tomoyuki; Tanaka, Kiwamu; Yasuda, Mari; Watanabe, Koichi; Sakai, Akihiro; Kameo, Yutaka; Kogure, Hiroto; Higuchi, Hidekazu; Takahashi, Kuniaki

JAEA-Data/Code 2011-011, 31 Pages, 2011/10

JAEA-Data-Code-2011-011.pdf:1.7MB

Simple and rapid methods to evaluate the radioactivity concentrations are required to be established for the near surface disposal of radioactive wastes generated from research facilities at Japan Atomic Energy Agency. In order to establish the methods to evaluate the radioactivity concentrations of miscellaneous solid wastes generated from research and testing reactors, we collected and analyzed samples from miscellaneous solid wastes generated by the decommissioning of JPDR (Japan Power Demonstration Reactor). In the present paper, we summarized data (262 data) about the radioactivity concentrations of the 7 important nuclides ($$^{3}$$H, $$^{14}$$C, $$^{60}$$Co, $$^{59}$$Ni, $$^{63}$$Ni, $$^{90}$$Sr, $$^{137}$$Cs) which accumulated by the analysis.

Journal Articles

Study on effectiveness assessment of proliferation resistance

Kuno, Yusuke; Oda, Takuji*; Tanaka, Satoru*; Fukasawa, Tetsuo*; Tanabe, Tomoyuki*; Tamai, Hiroshi; Horio, Kenta*; Hamasaki, Manabu*; Shinohara, Nobuo*; Ikeda, Yuta*

Proceedings of INMM 52nd Annual Meeting (CD-ROM), 10 Pages, 2011/07

The substance and implication of PR from the viewpoints of risk evaluation on nuclear proliferation was studied in this paper. As an example, ten next-generation reprocessing technology candidates were evaluated with GIF PR and PP methodology to find degree of relative difference in PR from the presently available technology - PUREX. PR effectiveness in proliferation risk was also assessed and it was found that the effectiveness of PR measures is subject to the status of each nation.

Journal Articles

High-pressure Raman spectroscopy of transition metal cyanides

Moritomo, Yutaka*; Matsuda, Tomoyuki*; Fuchikawa, Ryota*; Abe, Yuta; Kamioka, Hayato*

Journal of the Physical Society of Japan, 80(2), p.024603_1 - 024603_5, 2011/02

 Times Cited Count:3 Percentile:29.52(Physics, Multidisciplinary)

Journal Articles

Stress and temperature dependence of the structure of the martensite and X-phase in Ni$$_{2}$$MnGa

Fukuda, Takashi*; Terai, Tomoyuki*; Kushida, Hiroaki*; Kakeshita, Tomoyuki*; Osakabe, Toyotaka; Kakurai, Kazuhisa

Philosophical Magazine, 90(14), p.1925 - 1935, 2010/05

 Times Cited Count:6 Percentile:40.78(Materials Science, Multidisciplinary)

The stress and temperature dependence of the structure of the X-phase in Ni$$_{2}$$MnGa has been investigated by neutron diffraction measurements under compressive stress to clarify the structural relationship among the P-, I-, M- and X-phases. The structure of the X-phase in Ni$$_{2}$$MnGa depends strongly on stress and temperature compared to the M- or I-phase. In association with the X $$rightarrow$$ M transformation, both the position and intensity of the satellite reflection changes drastically, regardless of stress and temperature, while with X $$rightarrow$$ P transformation, the intensity of the satellite reflection fades gradually. For the I $$rightarrow$$ X transformation, the position and intensity of the satellite changes drastically when transformation occur under compressive stress, while the changes are continuous under zero stress. These results strongly suggest the existence of a multicritical point in Ni$$_{2}$$MnGa.

Journal Articles

Structural relation between the X-phase and other phases in Ni$$_{2}$$MnGa

Kakeshita, Tomoyuki*; Fukuda, Takashi*; Terai, Tomoyuki*; Osakabe, Toyotaka; Kakurai, Kazuhisa

Materials Science Forum, 635, p.49 - 54, 2009/12

We have investigated stress and temperature dependences of the structure of the X-phase in Ni$$_{2}$$MnGa to understand structural relation between the X-phase and other phases. We found that the structure change associated with the transformation from the intermediate (I-) phase to the X-phase is discontinuous under a compressive stress, while it is continuous under zero stress. In addition, the transformation from the X-phase to the L2$$_{1}$$-type parent phase is continuous regardless of applied stress. These results strongly suggest the existence of multi-critical point in Ni$$_{2}$$MnGa.

Journal Articles

Experience on preparation of LSD spikes for MOX samples

Sumi, Mika; Abe, Katsuo; Kageyama, Tomio; Nakazawa, Hiroaki; Katchi, Tomokazu*; Murakami, Yoshiki*; Hishi, Tomoyuki*; Ai, Hironobu*

Proceedings of INMM 50th Annual Meeting (CD-ROM), 9 Pages, 2009/07

Currently, many laboratories who measure Pu and U concentration by isotope dilution mass spectrometry (IDMS) use Large Size Dried (LSD) spikes, which contain both Pu and U in individual vials. Plutonium Fuel Development Center (PFDC) prepared LSD spikes for MOX samples and has been used while LSD spikes prepared at inspection laboratories and commercially supplied are mainly aimed to measure input solution for reprocessing. Difficulties of importing reference materials are increasing though the needs of Pu reference materials are increasing. Stable securing Pu reference material is essential for facility operation and it is considered to be important to acquire technique to prepare domestic Pu reference material. Pu were prepared from MOX powder at PFDC and used for LSD spike preparation. Practical tests were performed with JNFL. Experience of preparation and utilization of LSD spike for MOX, consideration of certification method for MOX-Pu will be explained also in this paper.

Journal Articles

Incommensurate structures of intermediate phase and martensite phase in Ni$$_{2}$$MnGa

Kushida, Hiroaki*; Fukuda, Kodai*; Terai, Tomoyuki*; Fukuda, Takashi*; Kakeshita, Tomoyuki*; Oba, Takuya*; Osakabe, Toyotaka; Kakurai, Kazuhisa; Kato, Kenichi*

Journal of Physics; Conference Series, 165, p.012054_1 - 012054_4, 2009/06

Journal Articles

Neutron diffraction study on stress-induced X-phase in Ni$$_{2}$$MnGa

Kushida, Hiroaki*; Terai, Tomoyuki*; Fukuda, Takashi*; Kakeshita, Tomoyuki*; Osakabe, Toyotaka; Kakurai, Kazuhisa

Scripta Materialia, 60(4), p.248 - 250, 2009/02

 Times Cited Count:8 Percentile:49.11(Nanoscience & Nanotechnology)

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