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Watanabe, So; Senzaki, Tatsuya; Shibata, Atsuhiro; Nomura, Kazunori; Koma, Yoshikazu; Nakajima, Yasuo
Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 6 Pages, 2011/12
Extraction chromatography experiments with two promising flow-sheets on genuine high level liquid wastes were carried out for demonstrating the feasibility of the method. One flow-sheet consists of CMPO/SiO
-P and HDEHP/SiO-P adsorbent columns, and the other consists of TODGA/ SiO-P and isoHex-BTP/SiO-P adsorbent columns. Although recovery yields of MA and decontamination factors of FPs obtained by those experiments were lower than the required values, the second flow-sheet is expected to achieve the required performance providing that some minor improvements on the flow-sheet or the adsorbents are applied.
Suzuki, Tatsuya*; Nomura, Masao*; Fujii, Yasuhiko*; Ikeda, Atsushi; Takaoka, Toru*; Oguma, Koichi*
Nihon Ion Kokan Gakkai-Shi, 21(3), p.328 - 333, 2010/09
Zinc isotope fractionation in an anion exchange resin has been investigated in hydrochloric acid solution by chromatographic technique. It was found that the heavier zinc isotopes were located disproportionately in the solution phase. The isotope fractionation coefficient was varied from the order of 10
to 10
depending on the hydrochloric acid concentration. The maximum isotope fractionation coefficient was obtained in 1 
hydrochloric acid, while the distribution coefficient of zinc became maximum at around 2 hydrochloric acid. This difference has been further discussed based on the calculated speciation and structural information derived from X-ray absorption spectroscopy.
Nomura, Yasushi*; Takahashi, Satoshi*; Okuno, Hiroshi
JAEA-Technology 2008-009, 273 Pages, 2008/03
JAEA-Technology-2008-009.pdf:8.92MB
Safety demonstration analyses were conducted under contract with the Ministry of Economic, Trade and Industry of Japan from 2001 to 2004 for the purpose of assuaging public jitters concerning the transport. The current transport routes and the past accident/incident records were surveyed, three accident scenarios, i.e., a fall from an overpass, an open fire after collision with an oil tank trailer, a fire caused by collision with 2-ton truck inside a tunnel were set up. Mechanical damages and thermal failures were analyzed using the finite element codes LS-DYNA and ABAQUS. In addition, criticality safety analyses were made using the continuous energy Monte Carlo code MVP for the transport casks damaged in reference to the previous mechanical and thermal analyses. Thus, the integrity of packaging against leakage of radioactive material was shown in the case of severe accidents anticipated to occur during transportation without any harmful effect to the public and environment.
Yamamura, Osamu; Yamamoto, Ryuichi; Nomura, Shigeo; Fujii, Yasuhiko*
Progress in Nuclear Energy, 50(2-6), p.666 - 673, 2008/03
Times Cited Count：4 Percentile：29.38(Nuclear Science & Technology)The application of safeguards to the Tokai Reprocessing Plant(TRP), the world's first reprocessing plant with a sole objective of commercial use, was made on try and error basis because it was the first experience for both the plant and the inspection sides. Through thirty years' faithful cooperation to the IAEA-initiated safeguards program, TRP contributed also to the developments of the international credibility upon the concept of safeguards system of Reprocessing plant in non-nuclear weapon countries. TRP also has been processing over 1,123 ton of spent fuels from the beginning of its active operation in Sept.'77. For 30 years operation of TRP, many technological problems have been overcome to obtain the stable and reliable operation. The process for establishments of maintenance technology in TRP was evaluated through the analysis of significant plant equipment failures reported to the Government and so on. Discussion in this paper is also emphasized that the safeguards system and the maintenance technologies developed by TRP have been applied to the first Rokkasho commercial reprocessing plant (RRP). Furthermore, this operation knowledge base can contribute to the design and construction of the next generation reprocessing plant.
Nomura, Yasushi*; Okuno, Hiroshi; Miyoshi, Yoshinori
Nuclear Technology, 148(3), p.235 - 243, 2004/12
Times Cited Count：3 Percentile：23.45(Nuclear Science & Technology)no abstracts in English
Nomura, Yasushi*; Okuno, Hiroshi; Miyoshi, Yoshinori
JAERI-Tech 2004-030, 64 Pages, 2004/03
JAERI-Tech-2004-030.pdf:4.59MB
no abstracts in English
Suyama, Kenya; Nouri, A.*; Mochizuki, Hiroki*; Nomura, Yasushi*
JAERI-Conf 2003-019, p.890 - 892, 2003/10
Isotopic composition is one of the most relevant data to be used in the calculation of burnup of irradiated nuclear fuel. Since autumn 2002, the Organisation for Economic Co-operation and Development/Nuclear Energy Agency OECD/NEA) has operated a database of isotopic composition; SFCOMPO, initially developed in Japan Atomic Energy research Institute. This paper describes latest version of SFCOMPO and the future development plan in OECD/NEA.
Okuno, Hiroshi; Ryufuku, Susumu*; Suyama, Kenya; Nomura, Yasushi; Tonoike, Kotaro; Miyoshi, Yoshinori
JAERI-Conf 2003-019, p.116 - 121, 2003/10
This paper outlines the data prepared for the 2nd version of Data Collection of the Nuclear Criticality Safety Handbook. These data are discussed in the order of its preliminary table of contents. The nuclear characteristic parameters (k
, M
, D) were derived, and subcriticality judgment graphs were drawn for eleven kinds of fuels which were often encountered in criticality safety evaluation of fuel cycle facilities. For calculation of criticality data, benchmark calculations using the combination of the continuous energy Monte Carlo criticality code MVP and the Japanese Evaluated Nuclear Data Library JENDL-3.2 were made. The calculation errors were evaluated for this combination. The implementation of the experimental results obtained by using NUCEF facilities into the 2nd version of the Data Collection is under discussion. Therefore, related data were just mentioned. A database is being prepared to retrieve revised data easily.
Kuroishi, Takeshi; Nomura, Yasushi
Journal of Nuclear Science and Technology, 40(6), p.433 - 440, 2003/06
Times Cited Count：2 Percentile：18.89(Nuclear Science & Technology)Effective source acceleration method is studied in criticality safety analysis for realistic spent fuel transport cask. Various axial burnup profiles based on in-core flux measurements are proposed in the OECD/NEA/BUC benchmark Phase II-C. In some cases, calculations by ordinary Monte Carlo method show very slow convergence of fission source distribution, and unacceptably large skipped cycles are needed. The matrix eigenvector calculation that has been developed and incorporated in the ordinary Monte Carlo calculation to improve the slow convergence is applied to the benchmark. The efficiency of this method depends on the precision of matrix elements. In a certain stage of insufficient convergence of fission source distribution, especially for this benchmark of very slow convergence, more acceleration procedure causes anomalous results because of large statistical fluctuations of matrix elements corresponding to low source levels. Therefore, we propose effective source acceleration method with less calculation time than increasing histories for the estimation of matrix elements.
Kuroishi, Takeshi; Hoang, A.; Nomura, Yasushi; Okuno, Hiroshi
JAERI-Tech 2003-021, 60 Pages, 2003/03
JAERI-Tech-2003-021.pdf:4.56MB
The reactivity effect of the asymmetry of axial burnup profile is studied for PWR spent fuel transport cask proposed in OECD/NEA Phase II-C benchmark. The axial burnup profiles are based on in-core flux measurements. Criticality calculations are performed with the continuous energy Monte Carlo code MCNP-4B2 and the nuclear data library JENDL-3.2. Calculations are carried out not only for cases in the benchmark but also for symmetric burnup cases. Both actinide-only approach and actinide plus fission product approach is considered. The end effect is more sensitive to higher burnup asymmetry. The axial fission distribution becomes strongly asymmetric as its peak shifts toward the fuel top end. The peak of fission distribution gets higher with the increase of either the burnup asymmetry or the assembly-averaged burnup. The conservatism of uniform axial burnup assumption for the actinide-only approach is estimated quantitatively in comparison with the keff result calculated with experiment-based strongest asymmetric axial burnup profile for the actinide plus fission product approach.
Nomura, Yasushi; Takada, Tomoyuki; Kadotani, Hiroyuki*; Kuroishi, Takeshi
JAERI-Tech 2003-020, 88 Pages, 2003/03
JAERI-Tech-2003-020.pdf:4.31MB
no abstracts in English
Nomura, Yasushi; Mochizuki, Hiroki*
JAERI-Tech 2002-068, 131 Pages, 2002/11
JAERI-Tech-2002-068.pdf:5.59MB
no abstracts in English
Kuroishi, Takeshi; Nomura, Yasushi
Proceedings of International Conference on the New Frontiers of Nuclear Technology; Reactor Physics, Safety and High-Performance Computing (PHYSOR 2002) (CD-ROM), 10 Pages, 2002/10
To accelerate the slow convergence of the fission source distribution, the matrix k calculation has been developed and incorporated in the ordinary Monte Carlo method. The acceleration can be performed by the fission source correction using the eigenvector of the fission matrix, if the coupling coefficients are approximately evaluated in the middle of Monte Carlo calculation. In this paper, we propose two effective applications of the matrix k, that is, the acceleration repetition method and the source generation method. The former simply repeats the matrix k calculation, and the result for the irradiated fuel pin cell shows enough effective to accelerate the fission source on the criticality estimation. However, in some cases of the loosely coupled multi unit system, the repetition of matrix k more than twice could not be carried out to get into convergence because of many units of low source level. The latter is newly devised here to apply to such cases. The checkerboard fuel storage rack is one of the typical cases, and the calculated results show the effectiveness of this method.
Suyama, Kenya; Katakura, Junichi; Kiyosumi, Takehide*; Kaneko, Toshiyuki*; Nomura, Yasushi
Journal of Nuclear Science and Technology, 39(1), p.82 - 89, 2002/01
Times Cited Count：8 Percentile：47.73(Nuclear Science & Technology)no abstracts in English
Suyama, Kenya; Murazaki, Minoru*; Mochizuki, Hiroki*; Nomura, Yasushi
JAERI-Tech 2001-074, 119 Pages, 2001/11
JAERI-Tech-2001-074.pdf:4.21MB
no abstracts in English
Nomura, Yasushi; Murazaki, Minoru*; Okuno, Hiroshi
JAERI-Data/Code 2001-029, 120 Pages, 2001/11
JAERI-Data-Code-2001-029.pdf:6.16MB
no abstracts in English
Okuno, Hiroshi; Nomura, Yasushi
Proceedings of the 2001 Topical Meeting on Practical Implementation of Nuclear Criticality Safety (CD-ROM), 8 Pages, 2001/11
The nuclear criticality safety handbook of Japan was first published in 1988, which was translated into English in 1995. This paper intends to introduce the American community of nuclear criticality safety to activities for revising the Japanese handbook, putting an emphasis on practical use of code validation. They include (1) publication of "Nuclear Criticality Safety Handbook, Version 2" and its English translation, (2) publication of "A Guide Introducing Burnup Credit, Preliminary Version," and (3) preparation of "Nuclear Criticality Safety Handbook, -Data Collection-, Version 2."
Mochizuki, Hiroki*; Suyama, Kenya; Nomura, Yasushi; Okuno, Hiroshi
JAERI-Data/Code 2001-020, 394 Pages, 2001/08
JAERI-Data-Code-2001-020.pdf:17.99MB
no abstracts in English
Hayashi, Takafumi*; Suyama, Kenya; Mochizuki, Hiroki*; Nomura, Yasushi
JAERI-Tech 2001-041, 158 Pages, 2001/06
JAERI-Tech-2001-041.pdf:5.15MB
no abstracts in English
Nomura, Yasushi; Tamaki, Hitoshi; Ito, Chihiro*; Saegusa, Toshiari*
JAERI-Data/Code 2001-012, 118 Pages, 2001/03
JAERI-Data-Code-2001-012.pdf:5.71MB
no abstracts in English
