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Journal Articles

Disposal and recycling; Safer disposal and reassuring recycling

Nishihara, Kenji

ImPACT Fujita Puroguramu Kokai Seika Hokokukai "Kaku Henkan Niyoru Koreberu Hoshasei Haikibutsu No Ohaba Na Teigen, Shigenka" Seika Hokokusho, Shiryoshu, p.28 - 31, 2019/03

In this project, long-lived fission products (LLFP) contained in conventional high-level radioactive wastes are separated and their life is reduced, and elements that can be used as resources are separated. By shortening the life of LLFP, it has been shown that it may be possible to dispose in intermediate depth of several tens of meters, meeting safety requirements, instead of geological disposal. In addition, for reassuring recycling of usable elements, possible exposure pathways were evaluated to estimate the safe concentration level of radioactivity.

Journal Articles

Investigation of system for volume-reduction and recycling of HLW

Nishihara, Kenji

ImPACT Fujita Puroguramu Kokai Seika Hokokukai "Kaku Henkan Niyoru Koreberu Hoshasei Haikibutsu No Ohaba Na Teigen, Shigenka" Seika Hokokusho, Shiryoshu, p.130 - 133, 2019/03

High level radioactive waste contains elements with various characteristics. It is possible to reduce the load on the disposal site by separating them according to those characteristics and appropriately dealing with them. In this project, we are working to shorten the life span of long-lived fission products (LLFP). When this technology is realized, high-level radioactive wastes will become new radioactive wastes with low radioactivity. As a result of investigation of disposal concept of new radioactive waste, it turned out that intermediate-depth disposal currently considered for low level radioactive waste may be suitable. Intermediate-depth disposal is a method of small-scale disposal in shallow locations as compared to geological disposal for conventional high-level radioactive waste. We conducted a safety assessment when this disposal is applied to new radioactive wastes, and found that it is possible to safely dispose of for the four LLFPs addressed by this project.

Journal Articles

Disposal of radioactive waste and partitioning-transmutation; Consideration of waste disposal from view point of source term

Nishihara, Kenji

Genshiryoku Bakkuendo Kenkyu (CD-ROM), 25(2), p.131 - 134, 2018/12

Impact of reduction of source term on design and safety assessment of disposal concept for high level radioactive waste is considered. Reduction of source term in partitioning and transmutation technology is shown with impact on disposal concept. Moreover, cost and technological readiness is outlined.

Journal Articles

Role of breakup processes in deuteron-induced spallation reactions at 100-200 MeV/nucleon

Nakayama, Shinsuke; Furutachi, Naoya; Iwamoto, Osamu; Watanabe, Yukinobu*

Physical Review C, 98(4), p.044606_1 - 044606_8, 2018/10

 Times Cited Count:7 Percentile:25.66(Physics, Nuclear)

Use of deuteron-induced spallation reactions at intermediate energies has recently been proposed for transmutation of several long-lived fission products (LLFPs). In the design study of a transmutation system using a deuteron primary beam, accurate cross section data of deuteron-induced reactions on the LLFPs are indispensable. In the present study, production cross sections of residual nuclei in the deuteron-induced reactions on $$^{93}$$Zr and $$^{107}$$Pd at $$100-200$$ MeV/nucleon are analyzed using DEURACS, in which the breakup processes are explicitly taken into account. The calculated values reproduced the experimental data quantitatively well. From a component-by-component analysis, it was found that the components of nucleon absorption make the significant contributions to residual nuclei production. This result strongly indicates that consideration of the breakup processes is essentially important to predict production of residual nuclei in deuteron-induced reactions.

Journal Articles

Release and transport behaviors of non-gamma-emitting fission products and actinides in steam and hydrogen atmospheres

Miwa, Shuhei; Ducros, G.*; Hanus, E.*; Bottomley, P. D. W.*; Van Winckel, S.*; Osaka, Masahiko

Nuclear Engineering and Design, 326, p.143 - 149, 2018/01

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

The release and transport behaviors of 13 non-gamma-emitting fission products (FPs) and actinides in steam and hydrogen atmospheres were investigated based on the chemical analysis of their deposits on the components of VERCORS test loops. The new findings were obtained; strontium release was significantly enhanced in hydrogen atmosphere and a part of released strontium was transported towards the lower temperature region, uranium release was enhanced in steam atmosphere but most of released uranium deposited at high temperature region.

Journal Articles

Estimation of $$Delta$$${it R}$/${it R}$ values by benchmark study of the M$"o$ssbauer Isomer shifts for Ru, Os complexes using relativistic DFT calculations

Kaneko, Masashi; Yasuhara, Hiroki*; Miyashita, Sunao*; Nakashima, Satoru*

Hyperfine Interactions, 238(1), p.36_1 - 36_9, 2017/11

AA2016-0447.pdf:0.46MB

 Times Cited Count:1 Percentile:29.73

We aim to evaluate the validity of density functional calculations to the bonding property for Ru and Os complexes. We performed the benchmarking of theoretical computational method with $$^{99}$$Ru, $$^{189}$$Os M$"o$ssbauer isomer shifts. As the result, the computational values of the electron densities at nucleus position correlated with the experimental M$"o$ssbauer isomer shifts.

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:9 Percentile:13.35(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

Present state of partitioning and transmutation of long-lived nuclides, 1; Significance of partitioning and transmutation and partitioning and transmutation systems

Minato, Kazuo; Tsujimoto, Kazufumi; Tanabe, Hiromi*; Fujimura, Koji*

Nippon Genshiryoku Gakkai-Shi, 59(8), p.475 - 479, 2017/08

no abstracts in English

Journal Articles

Current activities and future plans for nuclear data measurements at J-PARC

Kimura, Atsushi; Harada, Hideo; Nakamura, Shoji; Iwamoto, Osamu; Toh, Yosuke; Koizumi, Mitsuo; Kitatani, Fumito; Furutaka, Kazuyoshi; Igashira, Masayuki*; Katabuchi, Tatsuya*; et al.

European Physical Journal A, 51(12), p.180_1 - 180_8, 2015/12

 Times Cited Count:1 Percentile:81.58(Physics, Nuclear)

Journal Articles

Influence of boron vapor on transport behavior of deposited CsI during heating test simulating a BWR severe accident condition

Sato, Isamu; Onishi, Takashi; Tanaka, Kosuke; Iwasaki, Maho; Koyama, Shinichi

Journal of Nuclear Materials, 461, p.22 - 28, 2015/06

We observed one of the simplified processes by conducting primitive experiments. CsI was heated at 1323 K to be vaporized and deposited on sampling parts with a temperature range of 1023 - 423 K and then B$$_{2}$$O$$_{3}$$ was vaporized at 1973 K to be reacted with Cs/I there. After heating tests, each sampling part was soaked into alkali water to dissolve the surface-deposits for ICP-MS analysis. The results showed that CsI deposited at the sampling parts kept above approx. 850 K was striped by B$$_{2}$$O$$_{3}$$ vapour. This behaviour will be thermodynamically discussed to study the Cs/I/B chemistry in the severe accidents.

Journal Articles

Influence of boron vapor on transport behavior of deposited CsI during heating test simulating a BWR severe accident condition

Sato, Isamu; Onishi, Takashi; Tanaka, Kosuke; Iwasaki, Maho; Koyama, Shinichi

Journal of Nuclear Materials, 461, p.22 - 28, 2015/06

 Times Cited Count:6 Percentile:39.55(Materials Science, Multidisciplinary)

In order to evaluate B influence on the release and transport of Cs and I during severe accidents, basic experiments have been performed on the interaction between deposited Cs/I compounds and vapor/aerosol B compounds. CsI and B$$_{2}$$O$$_{3}$$ were utilized as a Cs/I compound and a B compound, respectively. Deposited CsI on the thermal gradient tube (TGT), which is exposed to temperatures ranging from 423 K to 1023 K was reacted with vapor/aerosol B$$_{2}$$O$$_{3}$$, and then observed to determine how it changed Cs/I decomposition profiles. As a result, vapor/aerosol B$$_{2}$$O$$_{3}$$ stripped a portion of deposited CsI within a temperature range from 830 K to 920 K to make gaseous CsBO$$_{2}$$ and I$$_{2}$$. In addition, gaseous I$$_{2}$$ was re-deposited at a temperature range from 530 K to 740 K, while CsBO$$_{2}$$ travelled through the sampling tubes and filters without deposition. It is implied that B influences Cs carriers such as CsBO$$_{2}$$ to transport Cs to the colder regions.

JAEA Reports

Handbook on Process and Chemistry of Nuclear Fuel Reprocessing, 3rd Edition

Committee of Handbook on Process and Chemistry of Nuclear Fuel Reprocessing

JAEA-Review 2015-002, 726 Pages, 2015/03

JAEA-Review-2015-002.pdf:43.63MB
JAEA-Review-2015-002(errata).pdf:0.21MB

The fundamental data on spent nuclear fuel reprocessing and related chemistry was collected and summarized as a new edition of "Handbook on Process and Chemistry of Nuclear Fuel Reprocessing". The purpose of this handbook is contribution to development of the fuel reprocessing and fuel cycle technology for uranium fuel and mixed oxide fuel utilization. Contents in this book was discussed and reviewed by specialists of science and technology on fuel reprocessing in Japan.

JAEA Reports

Status and future plan of research and development on partitioning and transmutation technology for long-lived nuclides in JAERI

Oigawa, Hiroyuki; Nishihara, Kenji; Minato, Kazuo; Kimura, Takaumi; Arai, Yasuo; Morita, Yasuji; Nakayama, Shinichi; Katakura, Junichi

JAERI-Review 2005-043, 193 Pages, 2005/09

JAERI-Review-2005-043.pdf:16.13MB

JAERI has been conducting research and development on partitioning and transmutation (P&T) technology for long-lived nuclides to develop the double-strata fuel cycle concept, in accordance with the Atomic Energy Commission's "Research and Development of Technologies for Partitioning and Transmutation of Long-lived Nuclides - Status and Evaluation Report" issued in 2000. The double-strata fuel cycle concept consists of four major processes: partitioning, fuel fabrication, transmutation, and fuel processing. The five-year achievement and future perspectives for the technology on these processes are presented in this report. It also provides an analytical study on impacts of introducing P&T technology on waste management, and on deployment of P&T for the future nuclear energy system.

Journal Articles

Analysis of nuclear fuel cycle related materials

Sato, Soichi*; Suzuki, Toru*; Hiyama, Toshiaki*; Watanabe, Kazuo

Bunseki, 2005(8), p.451 - 457, 2005/08

no abstracts in English

Journal Articles

Current status and newly introduced analytical techniques for safeguards environmental samples at JAERI

Magara, Masaaki; Usuda, Shigekazu; Sakurai, Satoshi; Watanabe, Kazuo; Esaka, Fumitaka; Hirayama, Fumio; Lee, C. G.; Yasuda, Kenichiro; Kono, Nobuaki; Inagawa, Jun; et al.

Proceedings of INMM 46th Annual Meeting (CD-ROM), 8 Pages, 2005/00

JAERI has been developing analytical techniques for ultra-trace amounts of nuclear materials in the environmental samples in order to contribute to the strengthened safeguards system. Development of essential techniques for bulk and particle analysis of the environmental swipe sample has been established as an ultra-trace analytical method of uranium and plutonium. In January 2003, JAERI was qualified as a member of the IAEA network analytical laboratories for environmental samples. Since then, JAERI has conducted the analysis of domestic and the IAEA samples. From Japanese fiscal year 2003, the second phase of the project was started for the development of advanced techniques, such as analyzing minor actinides and fission products as well as uranium and plutonium, particle analysis using fission-track technique, more efficient particle analysis using ICP-TOFMS and screening by X-ray fluorescent analysis. This paper deals with the progress in the development of the new techniques, applications and future perspective.

Journal Articles

Research and development activities for accelerator driven system at JAERI

Tsujimoto, Kazufumi; Sasa, Toshinobu; Nishihara, Kenji; Oigawa, Hiroyuki; Takano, Hideki*

Proceedings of International Conference on Physics of Fuel Cycles and Advanced Nuclear Systems; Global Developments (PHYSOR 2004) (CD-ROM), 8 Pages, 2004/04

The Japan Atomic Energy Research Institute (JAERI) is developing an Accelerator Driven System (ADS) for transmutation of nuclear waste such as minor actinide (MA) and long-lived fission product (LLFP). To study and evaluate the feasibility of ADS by physical and engineering viewpoints, the Transmutation Experimental Facility (TEF) is proposed under a framework of J-PARC (Japan Proton Accelerator Research Complex) project. The TEF consists of two facilities named as Transmutation Physics Experimental Facility (TEF-P) and ADS Target Test Facility (TEF-T). The TEF-P consists of a zero-power critical assembly which is operated with a low power proton beam to research the reactor physics and the controllability of ADS. The TEF-T is a facility for material irradiation and partial mockup of beam window which can accept a maximum 600MeV-200kW proton beam into the Pb-Bi eutectic target. The purposes, experimental items and the specifications of the facilities are described.

JAEA Reports

Photon and decay data libraries for ORIGEN2 code based on JENDL FP decay data file 2000

Katakura, Junichi; Yanagisawa, Hiroshi

JAERI-Data/Code 2002-021, 81 Pages, 2002/11

JAERI-Data-Code-2002-021.pdf:3.62MB

no abstracts in English

Journal Articles

Research and development on the nuclear fuels

Sawa, Kazuhiro; Yamashita, Toshiyuki; Minato, Kazuo; Arai, Yasuo; Konashi, Kenji*

Nippon Genshiryoku Gakkai-Shi, 44(9), p.657 - 662, 2002/09

no abstracts in English

Journal Articles

Evaluation of photon shielding capability for epithermal neutron detection during reactivity-initiated power burst experiments

Yanagisawa, Hiroshi; Nakajima, Ken; Ono, Akio; Miyoshi, Yoshinori

Journal of Nuclear Science and Technology, 39(7), p.800 - 803, 2002/07

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Determination of $$gamma$$-ray exposure rate from short-lived fission products under criticality accident conditions

Yanagisawa, Hiroshi; Ono, Akio; Aizawa, Eiju

Journal of Nuclear Science and Technology, 39(5), p.499 - 505, 2002/05

 Times Cited Count:4 Percentile:68.96(Nuclear Science & Technology)

no abstracts in English

194 (Records 1-20 displayed on this page)