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Journal Articles

Nitride fuel cycle, 2; R&D for minor actinides transmutation

Takano, Masahide

NSA/Commentaries, No.24, p.163 - 167, 2019/03

This article summarizes R&D status of the nitride fuel cycle for minor actinides (MA) transmutation. Status of nitride fuel fabrication, material properties and fuel performance code, pyrochemical reprocessing, and nitrogen-15 enrichment are described.

Journal Articles

Measurements of gamma-ray emission probabilities in the decay of americium-244g

Nakamura, Shoji; Terada, Kazushi*; Kimura, Atsushi; Nakao, Taro*; Iwamoto, Osamu; Harada, Hideo; Uehara, Akihiro*; Takamiya, Koichi*; Fujii, Toshiyuki*

Journal of Nuclear Science and Technology, 56(1), p.123 - 129, 2019/01

 Percentile:100(Nuclear Science & Technology)

Accurate data of $$gamma$$-ray emission probabilities are frequently needed when one quantitatively determines the amount of isotope by $$gamma$$-ray measurements or obtains neutron capture cross-sections using them. Americium-243, one of the most important minor actinides, produces $$^{244}$$Am after neutron capture. The 744-keV $$gamma$$-ray decaying from the ground state of $$^{244}$$Am has a relatively large $$gamma$$-ray emission probability c.a. 66%, however, its uncertainty is as large as 29%. The uncertainty of the $$gamma$$-ray emission probability leads to a major factor of the systematic uncertainty on determining an amount of isotope, and therefore the $$gamma$$-ray emission probability was measured by using an activation method and an examined level structure of $$^{244}$$Cm. In this study, the emission probability of 744-keV $$gamma$$ ray was derived as 66.5$$pm$$1.1%, and its uncertainty was improved from 29% to 2%.

Journal Articles

Evaluation of mean time between accidental interruptions for accelerator klystron systems based on the reliability engineering method

Takei, Hayanori; Furukawa, Kazuro*; Yano, Yoshiharu*; Ogawa, Yujiro*

Journal of Nuclear Science and Technology, 55(9), p.996 - 1008, 2018/09

 Percentile:100(Nuclear Science & Technology)

Experiences with existing high-power proton accelerators indicate that frequent beam trips are inevitable. One of the reasons for such frequent beam trips is the accidental interruption to protect accelerators against fatal failures. Generally, the failure frequency for the general machinery can be evaluated based on a reliability database for its components. On the other hand, the beam-trip frequency for the accidental interruption was not evaluated based on the reliability database because it has not yet been established. A principal reason for the lack of this reliability database is the inconsistency of data collection and analysis methods among laboratories. For example, there are at least three methods to estimate Mean Time Between accidental Interruptions (MTBI) for klystron systems. In the present study, the MTBI of the klystron systems of an electron/positron injector linac at the High Energy Accelerator Research Organization (KEK) was evaluated based on the reliability engineering method, in order to build the reliability database using the unified data collection and analysis method. As the result, the mean values of the MTBI by the traditional three methods were evaluated as 30.9, 32.0, and 50.4 hours. On the other hand, that by the reliability engineering method was evaluated as 57.3 hours, i.e., more than 1.14 times of the traditional results. Although these results are obviously different from traditional results, it appears that the present estimation based on the reliability engineering method is suitable for the MTBI of accelerator components as typified by the klystron system.

Journal Articles

Study on heterogeneous minor actinide loading fast reactor core concepts with improved safety

Ohgama, Kazuya; Oki, Shigeo; Kitada, Takanori*; Takeda, Toshikazu*

Proceedings of 21st Pacific Basin Nuclear Conference (PBNC 2018) (USB Flash Drive), p.942 - 947, 2018/09

Journal Articles

Target test facility for ADS and cross-section experiment in J-PARC

Meigo, Shinichiro; Iwamoto, Hiroki; Matsuda, Hiroki; Takei, Hayanori

Journal of Physics; Conference Series, 1021(1), p.012072_1 - 012072_4, 2018/06

no abstracts in English

Journal Articles

Conceptual design study of beam window for accelerator-driven system with subcriticality adjustment rod

Sugawara, Takanori; Eguchi, Yuta; Obayashi, Hironari; Iwamoto, Hiroki; Tsujimoto, Kazufumi

Nuclear Engineering and Design, 331, p.11 - 23, 2018/05

 Times Cited Count:1 Percentile:38.14(Nuclear Science & Technology)

This study aims to perform the coupled analysis for the feasible beam window concept. To mitigate the design condition, namely to reduce the necessary proton beam current, subcriticality adjustment rod (SAR) was installed to the ADS core. The burnup analysis was performed for the ADS core with SAR and the results indicated that the maximum proton beam current during the burnup cycle was reduced from 20 to 13.5 mA. Based on the burnup analysis result, the coupled analysis; particle transport, thermal hydraulics and structural analyses, was performed. As the final result, the most robust beam window design; the hemisphere shape, the outer radius = 235 mm, the thickness at the top of the beam window = 3.5 mm and the factor of safety for the buckling = 9.0, was presented. The buckling pressure was 2.2 times larger than the previous one and more feasible beam window concept was presented through this study.

Journal Articles

Design of LBE spallation target for ADS Target Test Facility (TEF-T) in J-PARC

Saito, Shigeru; Obayashi, Hironari; Wan, T.; Okubo, Nariaki; Sugawara, Takanori; Endo, Shinya; Sasa, Toshinobu

Proceedings of 13th International Topical Meeting on Nuclear Applications of Accelerators (AccApp '17) (Internet), p.448 - 457, 2018/05

JAEA proposes transmutation of minor actinides by accelerator-driven systems (ADS). To obtain the data for ADS design, JAEA plans to construct the ADS Target Test Facility (TEF-T) within the framework of the J-PARC project. In TEF-T, a 250 kW proton-beam-driven LBE (Lead-Bismuth Eutectic) spallation target will be installed to prepare an irradiation database for candidate ADS structural materials. Design activities of the LBE target and target trolley have been progressed. Conceptual design of hot-cells for LBE target loop maintenance and PIE (Post Irradiation Examination) of irradiated samples have been finished. Two LBE loops were manufactured. One is a loop for TEF-T target mock-up and the other is that for collection of material corrosion characteristics in flowing LBE. Oxygen potential control systems for LBE flow have been also developed. Remote handling tests for the target exchange are underway. In this paper, current activities and studies to realize TEF-T will be presented.

Journal Articles

Cross section measurement in J-PARC for neutronics of the ADS

Meigo, Shinichiro; Matsuda, Hiroki; Iwamoto, Hiroki

Proceedings of 13th International Topical Meeting on Nuclear Applications of Accelerators (AccApp '17) (Internet), p.396 - 402, 2018/05

no abstracts in English

Journal Articles

Beam extraction by the laser charge exchange method using the 3-MeV LINAC in J-PARC

Takei, Hayanori; Hirano, Koichiro; Tsutsumi, Kazuyoshi; Meigo, Shinichiro

Plasma and Fusion Research (Internet), 13(Sp.1), p.2406012_1 - 2406012_6, 2018/03

The Japan Proton Accelerator Research Complex (J-PARC) has a plan to build the Transmutation Physics Experimental Facility (TEF-P), in which a 400-MeV negative proton (H$$^{-}$$) beam will be delivered from the J-PARC linac. Since the TEF-P requires a stable proton beam with a power of less than 10 W, a stable and meticulous beam extraction method is required to extract a small amount of the proton beam from the high power beam using 250 kW. To fulfil this requirement, the Laser Charge Exchange (LCE) method has been developed. To demonstrate the charge exchange of the H$$^{-}$$, a preliminary LCE experiment was conducted using a linac with energy of 3 MeV in J-PARC. As a result of the experiment, a charge-exchanged H$$^{+}$$ beam with a power of about 8 W equivalent and an accuracy of about 2% was obtained under the J-PARC linac beam condition.

Journal Articles

Beam extraction by the laser charge exchange method using the 3-MeV linac in J-PARC

Takei, Hayanori; Hirano, Koichiro; Meigo, Shinichiro; Tsutsumi, Kazuyoshi*

Proceedings of 6th International Beam Instrumentation Conference (IBIC 2017) (Internet), p.435 - 439, 2018/03

The Japan Proton Accelerator Research Complex (J-PARC) has a plan to build the Transmutation Physics Experimental Facility (TEF-P), in which a 400-MeV negative proton (H$$^{-}$$) beam will be delivered from the J-PARC linac. Since the TEF-P requires a stable proton beam with a power of less than 10 W, a stable and meticulous beam extraction method is required to extract a small amount of the proton beam from the high power beam using 250 kW. To fulfil this requirement, the Laser Charge Exchange (LCE) method has been developed. To demonstrate the charge exchange of the H$$^{-}$$, a preliminary LCE experiment was conducted using a linac with energy of 3 MeV in J-PARC. As a result of the experiment, a charge-exchanged H$$^{+}$$ beam with a power of about 8 W equivalent and an accuracy of about 2% was obtained under the J-PARC linac beam condition.

Journal Articles

Method to reduce long-lived fission products by nuclear transmutations with fast spectrum reactors

Chiba, Satoshi*; Wakabayashi, Toshio*; Tachi, Yoshiaki; Takaki, Naoyuki*; Terashima, Atsunori*; Okumura, Shin*; Yoshida, Tadashi*

Scientific Reports (Internet), 7(1), p.13961_1 - 13961_10, 2017/10

 Times Cited Count:2 Percentile:42.02(Multidisciplinary Sciences)

Transmutation of long-lived fission products (LLFPs: $$^{79}$$Se, $$^{93}$$Zr, $$^{99}$$Tc, $$^{107}$$Pd, $$^{129}$$I, and $$^{135}$$Cs) into short-lived or non-radioactive nuclides by fast neutron spectrum reactors without isotope separation has been proposed as a solution to the problem of radioactive wastes disposal. Despite investigation of many methods, such transmutation remains technologically difficult. To establish an effective and efficient transmutation system, we propose a novel neutron moderator material, yttrium deuteride (YD$$_{2}$$), to soften the neutron spectrum leaking from the reactor core. Neutron energy spectra and effective half-lives of LLFPs, transmutation rates, and support ratios were evaluated with the continuous-energy Monte Carlo code MVP-II/MVP-BURN and the JENDL-4.0 cross section library. With the YD$$_{2}$$ moderator in the radial blanket and shield regions, effective half-lives drastically decreased from 10$$^{6}$$ to 10$$^{2}$$ years and the support ratios reached 1.0 for all six LLFPs. This successful development and implementation of a transmutation system for LLFPs without isotope separation contribute to developing a self-consuming cycle of LLFPs using fast spectrum reactors to reduce radioactive waste.

Journal Articles

Measurement of aluminum activation cross section and gas production cross section for 0.4 and 3-GeV protons

Meigo, Shinichiro; Nishikawa, Masaaki; Iwamoto, Hiroki; Matsuda, Hiroki

EPJ Web of Conferences (Internet), 146, p.11039_1 - 11039_4, 2017/09

 Percentile:100

no abstracts in English

Journal Articles

Research and development in Japan Atomic Energy Agency

Tsujimoto, Kazufumi

Enerugi Rebyu, 37(9), p.11 - 14, 2017/09

no abstracts in English

Journal Articles

Present status of the laser charge exchange test using the 3-MeV linac in J-PARC

Takei, Hayanori; Chishiro, Etsuji; Hirano, Koichiro; Kondo, Yasuhiro; Meigo, Shinichiro; Miura, Akihiko; Morishita, Takatoshi; Oguri, Hidetomo; Tsutsumi, Kazuyoshi

Proceedings of 5th International Beam Instrumentation Conference (IBIC 2016) (Internet), p.736 - 739, 2017/03

The Accelerator-driven System (ADS) is one of the candidates for transmuting long-lived nuclides, such as minor actinide (MA), produced by nuclear reactors. For efficient transmutation of the MA, a precise pre-diction of neutronics of ADS is required. In order to obtain the neutronics data for the ADS, the Japan Pro-ton Accelerator Research Complex (J-PARC) has a plan to build the Transmutation Physics Experimental Facility (TEF-P), in which a 400-MeV negative proton (H$$^{-}$$) beam will be delivered from the J-PARC linac. Since the TEF-P requires a stable proton beam with a power of less than 10W, a stable and meticulous beam extraction method is required to extract a small amount of the proton beam from the high power beam using 250kW. To fulfil this requirement, the Laser Charge Exchange (LCE) method has been developed. The LCE strips the electron of the H$$^{-}$$ beam and neutral protons will separate at the bending magnet in the proton beam transport. To demonstrate the charge exchange of the H$$^{-}$$, a preliminary LCE experiment was conducted using a linac with energy of 3MeV in J-PARC. As a result of the experiment, a charge-exchanged H$$^{+}$$ beam with a power of about 5W equivalent was obtained under the J-PARC linac beam condition, and this value almost satisfied the power requirement of the proton beam for the TEF-P.

Journal Articles

Preliminary results of the laser charge exchange test using the 3-MeV linac in J-PARC

Takei, Hayanori; Hirano, Koichiro; Tsutsumi, Kazuyoshi; Chishiro, Etsuji; Miura, Akihiko; Kondo, Yasuhiro; Morishita, Takatoshi; Oguri, Hidetomo; Meigo, Shinichiro

Proceedings of 13th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.987 - 991, 2016/11

Accelerator-driven system (ADS) is one of candidates to transmute long-lived nuclides such as minor actinide (MA) produced at nuclear reactor. For efficient transmutation of the MA, precise prediction of neutronics of ADS is indispensable. In order to obtain the neutronics data for the ADS, J-PARC has a plan to build the Transmutation Physics Experimental Facility (TEF-P). Since the TEF-P requires stable power of the beam and will operate with thermal power less than 500 W and the proton beam power of 10 W so that a stable and meticulous beam extraction method is required to extract small amount of the beam from the high power LINAC beam with 250 kW. To fulfill requirement, Laser charge exchange method (LCE) has been developed for delivery of 400-MeV proton beam with 25Hz to the TEF-P. The LCE strips the electron of H$$^{-}$$ beam and H$$^{0}$$ will separate at the bending magnet at the proton beam transport. The LCE device consists of YAG-laser with high power as 1.6 J/shot and 25 Hz and transport control system with high accuracy of the beam position. For the demonstration of the charge exchange of the H$$^{-}$$, the further LCE tests is conducted using H$$^{-}$$ beam with energy of 3-MeV at RFQ test stand in J-PARC. In this paper, present status of LCE tests is presented.

Journal Articles

Feasibility study of nuclear transmutation by negative muon capture reaction using the PHITS code

Abe, Shinichiro; Sato, Tatsuhiko

EPJ Web of Conferences (Internet), 122, p.04002_1 - 04002_6, 2016/06

 Percentile:100

Nuclear transmutation has been investigated to reduce long-lived fission products (LLFPs) in high level radioactive wastes. However, the nuclear transmutation is difficult for some LLFPs (e.g., $$^{90}$$Sr, $$^{126}$$Sn and $$^{137}$$Cs) having small cross-sections of fission and neutron capture. Negative muon is examined to be applied for the nuclear transmutation. Low energy negative muon is captured on an atom, and then it can decay or be further captured on its nucleus. When negative muon is captured on nucleus, some light particles and residual nucleus are produced. Negative muon capture process has been implemented into latest version of PHITS. In this study, we studied the feasibility of nuclear transmutation by negative muon capture reaction for LLFPs using PHITS. Negative muon capture reaction on 90Sr is simulated. It is found that 94% of negative muons are captured on nucleus, and 66% of $$^{90}$$Sr become stable nuclides or radioactive nuclides having less than 20 days. It is also found that 15% of $$^{90}$$Sr become $$^{87}$$Rb having longer half-life than that of $$^{90}$$Sr.

Journal Articles

Current status and future plan of research and development on partitioning and transmutation based on double-strata concept in JAEA

Tsujimoto, Kazufumi; Sasa, Toshinobu; Maekawa, Fujio; Matsumura, Tatsuro; Hayashi, Hirokazu; Kurata, Masaki; Morita, Yasuji; Oigawa, Hiroyuki

Proceedings of 21st International Conference & Exhibition; Nuclear Fuel Cycle for a Low-Carbon Future (GLOBAL 2015) (USB Flash Drive), p.657 - 663, 2015/09

To continue the utilization of the nuclear fission energy, the management of the high-level radioactive waste is one of the most important issues to be solved. Partitioning and Transmutation technology of HLW is expected to be effective to mitigate the burden of the HLW disposal by reducing the radiological toxicity and heat generation. The Japan Atomic Energy Agency (JAEA) has been conducting the research and development on accelerator-driven subcritical system (ADS) as a dedicated system for the transmutation of long-lived radioactive nuclides. This paper overviews the recent progress and future R&D plan of the study on the ADS and related fuel cycle technology in JAEA.

Journal Articles

Design study of accelerator-driven system for minor actinide transmutation in JAEA

Tsujimoto, Kazufumi; Nishihara, Kenji; Takei, Hayanori; Sugawara, Takanori; Iwamoto, Hiroki; Sasa, Toshinobu

NEA/NSC/R(2015)2 (Internet), p.254 - 261, 2015/06

The Japan Atomic Energy Agency (JAEA) has been conducting the research and development (R&D) on accelerator-driven system (ADS) as a dedicated transmutation system of long-lived radioactive nuclides. The ADS proposed by JAEA is a lead-bismuth eutectic (LBE) cooled fast subcritical reactor with thermal output of 800 MW. For ADS to play important roles in the nuclear fuel cycle, several critical issues have to be resolved. The critical issue in the design of the ADS is the engineering feasibility of the beam window for the high power spallation target. Although a feasible concept of the beam window for the ADS was proposed in our previous work. To mitigate the thermal load of the beam window not only in the normal operation but also in the transient situations, the R&D for the mechanism of reactivity adjustment and the accelerator design have been performed in JAEA.

JAEA Reports

Effect of experiments using Transmutation Physics Experimental Facility on the reduction of uncertainties in reactor physics parameters of an accelerator-driven system

Iwamoto, Hiroki; Nishihara, Kenji; Katano, Ryota*; Fukushima, Masahiro; Tsujimoto, Kazufumi

JAEA-Research 2014-033, 82 Pages, 2015/03

JAEA-Research-2014-033.pdf:6.53MB

The effect of experiments using Transmutation Physics Experimental Facility (TEF-P) is analysed from the viewpoint of the reduction of uncertainties in reactor physics parameters (criticality and coolant void reactivity) of an accelerator-driven system (ADS). The analysis is conducted by the nuclear-data adjustment method using JENDL-4.0 on the assumption that ve types of reactor physics experiments (a total of 44 experiments) are performed in TEF-P: (1) criticality experiment, (2) lead void reactivity experiment, (3) reaction rate ratio experiment, (4) sample reactivity experiment, and (5) fuel replacement reactivity experiment. As the result, 1.0% of uncertainty in criticality is found to be reduced to approximately 0.4%, and effective experiments for the reduction of uncertainty in criticality and coolant void reactivity are shown to be fuel replacement reactivity experiments and lead void reactivity experiments, respectively. Although these effects depend largely on the composition and amount of minor-actinide (MA) fuels, it is found that a combination of different types of experiments and database of existing experiments is effective in reducing the uncertainties.

Journal Articles

Transmutation experimental facility for research and development of accelerator-driven system in JAEA

Tsujimoto, Kazufumi; Sasa, Toshinobu; Nishihara, Kenji; Sugawara, Takanori; Iwamoto, Hiroki; Takei, Hayanori

Proceedings of Joint IGORR 2014 & IAEA Technical Meeting (Internet), 10 Pages, 2014/00

Partitioning and Transmutation technology is expected to be effective to mitigate the burden of the HLW disposal. The Japan Atomic Energy Agency (JAEA) has been conducting the research and development (R&D) on accelerator-driven system (ADS) as a dedicated transmutation system of long-lived radioactive nuclides. For ADS to play important roles in the nuclear fuel cycle, several critical issues have to be resolved. To foster the R&D for most of above mentioned technical issues, JAEA plans to build the Transmutation Experimental Facility (TEF) which consists of two buildings: the Transmutation Physics Experimental Facility (TEF-P) and the ADS Target Test Facility (TEF-T). TEF-P is a zero-power critical facility which is operated with a low power proton beam to research the reactor physics and the controllability of ADS. Using this TEF-P facility, many experimental studies are planned.

139 (Records 1-20 displayed on this page)