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Journal Articles

Thermodynamic and thermophysical properties of the actinide nitrides

Uno, Masayoshi*; Nishi, Tsuyoshi*; Takano, Masahide

Comprehensive Nuclear Materials, 2nd Edition, Vol.7, p.202 - 231, 2020/08

On the thermodynamic and thermophysical properties of the actinide nitrides in Comprehensive Nuclear Materials published by Elsevier as the first edition in 2012, we have revised them by adding some brand-new data. The main topics added are the solid solubility of the actinide nitrides into the zirconium nitride matrix for transmutation fuel, the lattice expansion of actinide nitrides induced by self-irradiation damage, the influence of defects accumulation on thermal conductivity, and the thermal expansion in curium nitride lattice.

Journal Articles

Research and development on pyrochemical treatment of spent nitride fuels for MA transmutation in JAEA

Hayashi, Hirokazu; Sato, Takumi; Shibata, Hiroki; Tsubata, Yasuhiro

NEA/NSC/R(2017)3, p.427 - 432, 2017/11

Transmutation of long-lived radioactive nuclides including minor actinides (MA: Np, Am, Cm) has been studied in Japan Atomic Energy Agency (JAEA). Pb-Bi cooled sub-critical accelerator-driven system (ADS) is regarded as one of the powerful tools for transmutation of MA under the double strata fuel cycle concept. Uranium-free MA-Pu nitride fuel was chosen as the first candidate for MA transmutation. Reprocessing of spent ADS fuel and reusing MA recovered from the spent ADS fuels is necessary to improve the transmutation ratio. A pyrochemical process has been proposed as the first candidate for reprocessing of the spent nitride fuel for MA transmutation, because this technique has some advantages over aqueous process, such as the resistance to radiation damage, which is an important issue for the fuels containing large amounts of highly radioactive MA, and feasibility for recovering expensive N-15 in the spent fuels to be reused. This paper overviews the current status of the technology development, including our recent study. Development of the anode suitable for electro-refining of nitride fuels and that of the apparatus for renitridation of the metals recovered in Cd cathode for 100g-Cd scale cold tests are main topics. Evaluation of the batch sizes of each process, which is necessary for estimating the scale of the engineering-apparatus, with considering the decay heat of MA and FP, will also be introduced.

Journal Articles

Local structure analysis of ZrN, and Dy$$_{0.5}$$Zy$$_{0.5}$$N surrogate materials for fast reactor nitride fuel

Yoneda, Yasuhiro; Tsuji, Takuya; Matsumura, Daiju; Okamoto, Yoshihiro; Takaki, Seiya; Takano, Masahide

Transactions of the Materials Research Society of Japan, 42(2), p.23 - 26, 2017/04

ZnN is a possible candidate for the diluent material for nitride fuels containing transuranium elements. Pellets of inert matrix material ZrN, and surrogate nitride fuel material Dy$$_{0.5}$$Zr$$_{0.5}$$N, are fabricated for the purpose of investigating the crystal structure. Lattice parameters of Dy$$_{1-x}$$Zr$$_x$$N followed the Vegard's low, in spite of the large lattice mismatch ($$sim$$ 7%) between DyN and ZrN. Local structure analysis was performed by X-ray absorption fine structure (XAFS) and atomic pair-distribution function (PDF) methods. The Zr-N nearest neighbor bond distance changed as changing the Dy composition. The complex local structure of DyN and ZrN is related to the preferable effects of ZrN.

Journal Articles

Development of nitride fuel cycle technology for transmutation of minor actinides

Hayashi, Hirokazu; Nishi, Tsuyoshi*; Sato, Takumi; Kurata, Masaki

Proceedings of 21st International Conference & Exhibition; Nuclear Fuel Cycle for a Low-Carbon Future (GLOBAL 2015) (USB Flash Drive), p.1811 - 1817, 2015/09

Transmutation of long-lived radioactive nuclides including minor actinides (MA: Np, Am, Cm) has been studied in Japan Atomic Energy Agency (JAEA). Accelerator-driven system (ADS) is regarded as one of the powerful tools for transmutation of MA under the double strata fuel cycle concept. Uranium-free nitride fuel was chosen as the first candidate fuel for MA transmutation using ADS. To improve the transmutation ratio of MA, reprocessing of spent fuel and reusing MA recovered from the spent fuels is necessary. Our target is to transmute 99% of MA arisen from commercial power reactor fuel cycle, with which the period until the radiotoxicity drops below that of natural uranium can be shorten from about 5000 years to about 300 years. A pyrochemical process has been proposed as the first candidate for reprocessing of the spent nitride fuel. This paper overviews the current status of the nitride fuel cycle technology. Our recent study on fuel fabrication, fuel property measurements, reprocessing of spent fuel, development of the property database of MA nitride fuel, and fuel behavior simulation code are introduced. Our research and development (R&D) plan based on the roadmap of the development is also introduced.

Journal Articles

Properties of minor actinide compounds relevant to nuclear fuel technology

Minato, Kazuo; Takano, Masahide; Nishi, Tsuyoshi; Ito, Akinori; Akabori, Mitsuo

Recent Advances in Actinide Science, p.317 - 322, 2006/06

To reduce the radiotoxicity of the high-level waste and to use the repository efficiently, recycling of minor actinides (MA: Np, Am, Cm) as well as plutonium is an option for the future nuclear fuel cycle. For MA-bearing fuel development, new facilities with inert atmosphere were installed and the thermal properties of minor actinide compounds, especially nitrides and oxides, were measured. Minor actinide nitrides were prepared by carbothermic reduction of the oxides. Lattice parameter and its thermal expansion were measured by high-temperature X-ray diffraction, and thermal diffusivity by laser flash method.

Journal Articles

Present status and future perspective of research and development on partitioning and transmutation technology at JAERI

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

Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 6 Pages, 2005/10

JAERI is engaging in the R&D on the Double-strata Fuel Cycle concept in accordance with the results of the check and review on the Partitioning and Transmutation (PT) technology made by the Atomic Energy Commission of Japan in 2000. As for the partitioning process, after the establishment of the "4-group Partitioning Process Concept", an innovative concept called ARTIST is also being studied. As for the fuel technology, minor actinide nitrides such as NpN and AmN were synthesized and their material properties have been measured. To reprocess the irradiated fuel, the pyrochemical process has been studied. The R&D of the accelerator-driven transmutation system are in progress for an accelerator, lead-bismuth, and a subcritical reactor. In addition, JAERI has started the high-intensity proton accelerator project (J-PARC), which includes the Transmutation Experimental Facility (TEF) as the Phase-II. The impact of PT technology on the backend of the nuclear energy utilization is also being discussed.

JAEA Reports

Fabrication of inert-matrix nitride fuel pins for the irradiation test at JMTR

Nakajima, Kunihisa; Iwai, Takashi; Kikuchi, Hironobu; Serizawa, Hiroyuki; Arai, Yasuo

JAERI-Research 2005-027, 42 Pages, 2005/09

JAERI-Research-2005-027.pdf:4.15MB

Nitride fuel pins containing inert matrix such as ZrN and TiN were fabricated for the irradiation test at JMTR, aiming at understanding irradiation behavior of nitride fuel for transmutation of minor actinides. Minor actinides are surrogated by plutonium in the present fuel pin. This report describes the preparation and characterization of fuel pellets, and fabrication of fuel pins. The irradiation for 11 cycles from May 2002 to November 2004 at JMTR was completed without any failure of fuel pins.

Journal Articles

Fabrication and electrochemical behavior of nitride fuel for future applications

Arai, Yasuo; Minato, Kazuo

Journal of Nuclear Materials, 344(1-3), p.180 - 185, 2005/09

 Times Cited Count:22 Percentile:82.13(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Diagnostics of pulsed plasma in laser ablation of boron compounds

Oba, Hironori; Saeki, Morihisa; Yokoyama, Atsushi

Proceedings of Plasma Science Symposium 2005/22nd Symposium on Plasma Processing (PSS-2005/SPP-22), p.331 - 332, 2005/01

A plasma produced by a XeCl laser ablation of boron compound was investigated using ion probes and a quadrupole mass spectrometer. Although the ablated neutral boron atoms had a natural abundance ratio, the isotope ratio of singly ionized boron atoms having a greatly different from the natural abundance ratio was observed. The observed isotope ratio of boron ions was different from the natural abundance.

JAEA Reports

Proceedings of the Symposium on Nitride Fuel Cycle Technology; July 28, 2004, JAERI, Tokai, Japan

Department of Materials Science

JAERI-Conf 2004-015, 143 Pages, 2004/12

JAERI-Conf-2004-015.pdf:17.09MB

This report is the Proceedings of the Symposium of Nitride Fuel Cycle Technology, which was held on July 28, 2004, at Tokai Research Establishment of Japan Atomic Energy Research Institute (JAERI). The purpose of this symposium is to exchange information and views on nitride fuel cycle technology among researchers from foreign and domestic organizations, and to discuss the recent and future research activities. The topics discussed in the symposium are Present State of the Technology Development in the World and Japan, Fabrication Technology, Property Measurement and Pyrochemical Process. The intensive discussion was made among 53 participants.

Journal Articles

Fission gas release and swelling in uranium-plutonium mixed nitride fuels

Tanaka, Kosuke*; Maeda, Koji*; Katsuyama, Kozo*; Inoue, Masaki*; Iwai, Takashi; Arai, Yasuo

Journal of Nuclear Materials, 327(2-3), p.77 - 87, 2004/05

no abstracts in English

Journal Articles

Research and development on accelerator-driven transmutation system at JAERI

Sasa, Toshinobu; Oigawa, Hiroyuki; Tsujimoto, Kazufumi; Nishihara, Kenji; Kikuchi, Kenji; Kurata, Yuji; Saito, Shigeru; Futakawa, Masatoshi; Umeno, Makoto*; Ouchi, Nobuo; et al.

Nuclear Engineering and Design, 230(1-3), p.209 - 222, 2004/05

 Times Cited Count:32 Percentile:88.72(Nuclear Science & Technology)

JAERI carries out research and development on accelerator-driven system (ADS) to transmute minor actinides and long-lived fission products. The system is composed of high intensity proton accelerator, lead-bismuth spallation target and lead-bismuth cooled subcritical core with nitride fuel. About 2,500 kg of minor actinide is loaded into the subcritical core. Annual transmutation amount using this system is 250 kg with 800MW of thermal output. A superconducting linear accelerator with the beam power of 30MW is connected to drive the subcritical core. Many research and development activities are under way and planned in the fields of subcritical core design, spallation target technology, lead-bismuth handling technology, accelerator development, and minor actinide fuel development. Especially, to study and evaluate the feasibility of the ADS from physics and engineering aspects, the Transmutation Experimental Facility (TEF) is proposed under a framework of the High-Intensity Proton Accelerator Project.

Journal Articles

Irradiation performance of uranium-plutonium mixed nitride fuel pins in JOYO

Inoue, Masaki*; Iwai, Takashi; Arai, Yasuo; Asaga, Takeo*

Proceedings of GLOBAL2003 Atoms for Prosperity; Updating Eisenhower's Global Vision for Nuclear Energy (CD-ROM), p.1694 - 1703, 2003/11

no abstracts in English

Journal Articles

Fabrication of nitride fuels for transmutation of minor actinides

Minato, Kazuo; Akabori, Mitsuo; Takano, Masahide; Arai, Yasuo; Nakajima, Kunihisa; Ito, Akinori; Ogawa, Toru

Journal of Nuclear Materials, 320(1-2), p.18 - 24, 2003/09

 Times Cited Count:50 Percentile:94.55(Materials Science, Multidisciplinary)

In the Japan Atomic Energy Research Institute, the concept of the transmutation of minor actinides (MA: Np, Am and Cm) with accelerator-driven systems is being studied. The MA nitride fuel has been chosen as a candidate because of the possible mutual solubility among the actinide mononitrides and excellent thermal properties besides supporting hard neutron spectrum. MA nitrides of AmN, (Am,Y)N, (Am,Zr)N and (Cm0.4Pu0.6)N were prepared from the oxides by the carbothermic reduction method. The prepared MA nitrides were examined by X-ray diffraction and the contents of impurities of oxygen and carbon were measured. The fabrication conditions for MA nitrides were improved so as to reduce the impurity contents. For an irradiation test of U-free nitride fuels, pellets of (Pu,Zr)N and PuN+TiN were prepared and a He-bonded fuel pin was fabricated. The irradiation test started in May 2002 and will go on for two years in the Japan Materials Testing Reactor.

Journal Articles

Research and development on nuclear transmutation, B; Transmutation fuel and reprocessing

Minato, Kazuo; Arai, Yasuo

Genshikaku Kenkyu, 47(6), p.31 - 38, 2003/06

no abstracts in English

Journal Articles

Research and development on accelerator-driven transmutation system at JAERI

Sasa, Toshinobu; Oigawa, Hiroyuki; Tsujimoto, Kazufumi; Nishihara, Kenji; Kikuchi, Kenji; Kurata, Yuji; Saito, Shigeru; Futakawa, Masatoshi; Umeno, Makoto*; Ouchi, Nobuo; et al.

Proceedings of 11th International Conference on Nuclear Engineering (ICONE-11) (CD-ROM), 9 Pages, 2003/04

JAERI carries out research and development on accelerator-driven system (ADS) to transmute minor actinides and long-lived fission products in high-level radioactive waste. The system is composed of high intensity proton accelerator, lead-bismuth spallation target and lead-bismuth cooled subcritical core with nitride fuel. About 2500 kg of minor actinide is loaded into the subcritical core. Annual transmutation amount using this system is 250 kg with 800MW of thermal output. A superconducting linear accelerator with the beam power of 20 - 30MW is connected to drive the subcritical core. The nitride fuel without uranium, such as (Np, Am, Pu)N, is selected. The fuel irradiated in the ADS is reprocessed by pyrochemical process followed by the re-fabrication of the fuel. Many research and development activities are under way. Especially, to study and evaluate the feasibility of the ADS from physics and engineering aspects, the Transmutation Experimental Facility (TEF) is proposed under a framework of the High-Intensity Proton Accelerator Project.

JAEA Reports

Post irradiation examination of (U,Pu)C and (U,Pu)N fuels for fast reactors; Destructive examination result of the fuel pins (Joint research)

Iwai, Takashi; Nakajima, Kunihisa; Kikuchi, Hironobu; Nagashima, Hisao; Kimura, Yasuhiko; Matsui, Hiroki; Arai, Yasuo

JAERI-Research 2002-038, 69 Pages, 2003/01

JAERI-Research-2002-038.pdf:12.46MB

Uranium-plutonium mixed carbide and nitiride fuel pins were fabricated in JAERI and irradiated at fast test rector JOYO based on the JAERI-JNC joint research program. The results of non-destructive and destructive post irradiation examinations cariied out at JNC were reported elsewhere. This report summarizes the results of destructive post irradiation examinations of (U,Pu)C and (U,Pu)N fuel pins carried out at JAERI.

Journal Articles

Study on the stability of AmN and (Am,Zr)N

Takano, Masahide; Ito, Akinori; Akabori, Mitsuo; Minato, Kazuo; Numata, Masami

Proceedings of GLOBAL2003 Atoms for Prosperity; Updating Eisenhower's Global Vision for Nuclear Energy (CD-ROM), p.2285 - 2291, 2003/00

Stability of AmN and (Am,Zr)N was studied comparatively from the viewpoints of the hydrolytic and evaporative behavior. AmN powder reacted with moisture to form hydroxide Am(OH)$$_{3}$$, while the solid solution (Am$$_{0.1}$$Zr$$_{0.9}$$)N remained stable as long as 1000 hours. Stabilization effect of ZrN was found to depend significantly on its mole fraction from the experiments on (Dy,Zr)N. In the oxidation experiments on (Dy,Zr)N by TG-DTA technique, rapid weight gain by the oxidation occurred above 700 K. Effect of ZrN on the stability against oxygen was slight. Nitrogen release by the evaporation of AmN and (Am$$_{0.1}$$Zr$$_{0.9}$$)N in He gas flow was measured by gas chromatography. Evaporation rate constants of AmN were obtained at 1623-1733 K. Although the evaporation rate constant of AmN in the solid solution were lower than those of the pure AmN, the selective evaporation of AmN from the solid slution were recognized, which resulted in a decrease in the Am mole fraction.

Journal Articles

Recovery of U by electrolysis of UN in LiCl-KCl eutectic melts

Shirai, Osamu; Uozumi, Koichi*; Iwai, Takashi; Arai, Yasuo

Journal of Nuclear Science and Technology, 39(Suppl.3), p.745 - 748, 2002/11

no abstracts in English

Journal Articles

Dissolution of uranium nitrides in LiCl-KCl eutectic melt

Hayashi, Hirokazu; Kobayashi, Fumiaki; Ogawa, Toru; Minato, Kazuo

Journal of Nuclear Science and Technology, 39(Suppl.3), p.624 - 627, 2002/11

The behavior of the dissolution of uranium nitrides, which is a component of the MA-U mixed nitride fuel, has been investigated. A mixture of uranium nitride, LiCl-KCl and CdCl$$_2$$ was contained in a double walled quartz reaction vessel. During the heating, the carrier gas helium was introduced to a gas chromatography apparatus equipped with an automatic gas sampler. A fraction of the gas was sampled and analyzed by a mass analyzer. Most of nitrogen is recovered as N$$_2$$ gas from uranium nitrides dissolving in the LiCl-KCl eutectic melt reacted with CdCl$$_2$$ above 550 $$^o$$C, which is higher than that for lanthanide nitrides.

76 (Records 1-20 displayed on this page)