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Journal Articles

Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex, 2; Neutron scattering instruments

Nakajima, Kenji; Kawakita, Yukinobu; Ito, Shinichi*; Abe, Jun*; Aizawa, Kazuya; Aoki, Hiroyuki; Endo, Hitoshi*; Fujita, Masaki*; Funakoshi, Kenichi*; Gong, W.*; et al.

Quantum Beam Science (Internet), 1(3), p.9_1 - 9_59, 2017/12

The neutron instruments suite, installed at the spallation neutron source of the Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC), is reviewed. MLF has 23 neutron beam ports and 21 instruments are in operation for user programs or are under commissioning. A unique and challenging instrumental suite in MLF has been realized via combination of a high-performance neutron source, optimized for neutron scattering, and unique instruments using cutting-edge technologies. All instruments are/will serve in world-leading investigations in a broad range of fields, from fundamental physics to industrial applications. In this review, overviews, characteristic features, and typical applications of the individual instruments are mentioned.

Journal Articles

Outline of Japan Atomic Energy Agency's Okuma Analysis and Research Center, 3; Laboratory-2

Ito, Masayasu; Ogawa, Miho; Inoue, Toshihiko; Yoshimochi, Hiroshi; Koyama, Shinichi; Koyama, Tomozo; Nakayama, Shinichi

Proceedings of 54th Annual Meeting of Hot Laboratories and Remote Handling (HOTLAB 2017) (Internet), 7 Pages, 2017/00

Laboratory-2 of the Okuma Analysis and Research Center will be used for the technological development of techniques to treat and dispose fuel debris, etc. The specific analytical content and its importance has been discussed by an experts committee in FY 2016. The committee regarded fuel debris retrieval and criticality control related topics as the most important content. As a result, it will be a priority to introduce equipment to perform examination such as shape and size measurement, compositional and nuclide analysis, hardness and toughness test, and radiation dose rate measurement. In addition, since sample will have high dose rates (1 Sv/h or more) at the time of reception, hot cells with enough radiation shielding ability will be used. In the hot cell, the pre-processing will be performed, such as cutting and dissolution of samples. Processed samples will be examined in concrete cells, steel cells, glove boxes and fume hoods. Detail design of Laboratory-2 started on FY 2017.

Journal Articles

Study on magnetic property change on neutron irradiated austenitic stainless steel

Nemoto, Yoshiyuki; Oishi, Makoto; Ito, Masayasu; Kaji, Yoshiyuki; Keyakida, Satoshi*

Hozengaku, 14(4), p.83 - 90, 2016/01

Authors previously reported that magnetic data obtained by using Eddy current method and AC magnetization method showed correlation with the increase of susceptibility of the irradiation assisted stress corrosion cracking (IASCC) on neutron irradiated austenitic stainless alloy specimens. To discuss the mechanism of the correlation, microstructure observation was conducted on the irradiated specimen, and magnetic permalloy phase (FeNi$$_{3}$$) formation along grain boundary was revealed in this work. From this result, the radiation induced magnetic phase formation along grain boundary seems to be a factor of the magnetic property change of the irradiated materials, and related to the correlation between magnetic data and IASCC susceptibility. In addition, sensor probe development was conducted in this work to obtain higher sensitivity and resolution. It was applied for magnetic measurement on type304 stainless steel irradiated up to different doses. In this case, magnetic ferrite phase was existed in the type304 stainless steel sample before irradiation therefore it was concerned that magnetic measurement on the irradiated ones would be disturbed by the magnetic signal from the pre-existing ferrite phase. In the magnetic measurements, increase of the magnetic data was clearly seen on the irradiated specimens. Thus, it was thought that the developed magnetic measurement technics can be applied for the irradiated austenite stainless steels which contain certain quantity of ferrite phase before irradiation.

Journal Articles

Study on magnetic property change on neutron irradiated austenitic stainless steel

Nemoto, Yoshiyuki; Oishi, Makoto; Ito, Masayasu; Kaji, Yoshiyuki

Nippon Hozen Gakkai Dai-12-Kai Gakujutsu Koenkai Yoshishu, p.105 - 112, 2015/07

Authors previously reported that Eddy current method and AC magnetization method have potential to be applied for development of diagnostic technics to detect the sign of material degradation before cracking on the austenitic stainless steels used as structural material in nuclear power plants. In typical austenitic stainless steels such as type304, magnetic ferrite phase would exist in the alloy before irradiation, and it is concerned to disturb the magnetic measurement on irradiated material. Magnetic measurements were conducted in this work on type304 austenitic stainless steel specimens irradiated up to different doses. In addition, microstructure observation was conducted on the area including grain boundary to discuss the correlation of magnetization on irradiated austenitic stainless alloy and grain boundary cracking. Obtained magnetic data on irradiated type304 stainless steel were seen clearly different from that on un-irradiated specimen, and showed positive correlation with radiation dose, therefore it was thought that magnetic measurement technics can be applied for the material which contains certain quantity of ferrite phase before irradiation. In the microstructural observation, magnetic phase (FeNi$$_{3}$$) formation along the grain boundary was revealed.

Journal Articles

Current post irradiation examination techniques at the JMTR Hot laboratory

Shibata, Akira; Kato, Yoshiaki; Oishi, Makoto; Taguchi, Taketoshi; Ito, Masayasu; Yonekawa, Minoru; Kawamata, Kazuo

KAERI/GP-418/2015, p.151 - 165, 2015/05

The JMTR stopped its operation in 2006 for refurbishment. The reactor facilities have been refurbished from 2007. After refurbishment, JMTR Hot laboratory is expected to perform various post irradiation examinations. In this report, installations of experimental apparatuses and recent experimental method are introduced. (1) A nano-indenter with radius spherical indenter. Inverse analysis using FEM could presume material constants from load-depth curve of indentation. Mechanical properties of oxide layer of zirconium alloy and irradiated stainless steel will be analyzed. (2) Transmission Electron Microscope (TEM). TEM is capable of imaging at a significantly higher resolution than light microscopes or normal SEM. JAEA installed a TEM apparatus (JEOL JEM-2800) in JMTR Hot laboratory. The maximum magnification is 150,000,000 times. It can be operated from a remote location using a computer network. This contributes to the convenience of remote researchers and reducing the amount of exposure.

Journal Articles

Evaluation of selected grades of beryllium metal as reflector materials for extended lifetime performance

Dorn, C. K.*; Tsuchiya, Kunihiko; Takemoto, Noriyuki; Ito, Masayasu; Hori, Junichi*; Chekushina, L.*; Hatano, Yuji*; Chakrov, P.*; Kawamura, Hiroshi

Proceedings of 6th International Symposium on Material Testing Reactors (ISMTR-6) (Internet), 9 Pages, 2013/10

no abstracts in English

JAEA Reports

Conceptual design of multipurpose compact research reactor; Annual report FY2011

Watahiki, Shunsuke; Hanakawa, Hiroki; Imaizumi, Tomomi; Nagata, Hiroshi; Ide, Hiroshi; Komukai, Bunsaku; Kimura, Nobuaki; Miyauchi, Masaru; Ito, Masayasu; Nishikata, Kaori; et al.

JAEA-Technology 2013-021, 43 Pages, 2013/07

JAEA-Technology-2013-021.pdf:5.12MB

The number of research reactors in the world is decreasing because of their aging. On the other hand, the necessity of research reactor, which is used for human resources development, progress of the science and technology, industrial use and safety research is increasing for the countries which are planning to introduce the nuclear power plants. From above background, the Neutron Irradiation and Testing Reactor Center began to discuss a basic concept of Multipurpose Compact Research Reactor (MCRR) for education and training, etc., on 2010 to 2012. This activity is also expected to contribute to design tool improvement and human resource development in the center. In 2011, design study of reactor core, irradiation facilities with high versatility and practicality, and hot laboratory equipment for the production of Mo-99 was carried out. As the result of design study of reactor core, subcriticality and operation time of the reactor in consideration of an irradiation capsule, and about the transient response of the reactor to the reactivity disturbance during automatic control operation, it was possible to do automatic operation of MCRR, was confirmed. As the result of design study of irradiation facilities, it was confirmed that the implementation of an efficient mass production radioisotope Mo-99 can be expected. As the result of design study with hot laboratory facilities, Mo-99 production, RI export devised considered cell and facilities for exporting the specimens quickly was designed.

JAEA Reports

Preliminary accident analysis for a conceptual design of a 10 MW multi-purpose research reactor

Park, C.; Tanimoto, Masataka; Imaizumi, Tomomi; Miyauchi, Masaru; Ito, Masayasu; Kaminaga, Masanori

JAEA-Technology 2012-039, 87 Pages, 2013/01

JAEA-Technology-2012-039.pdf:3.55MB

Preliminary accident analysis has been carried out for a LOFA (Loss of Flow Accident) and RIAs (Reactivity Insertion Accidents) of the conceptual 10 MW MRR (multi-purpose research reactor) under design study by using the RELAP5/MOD3 code in order to provide the preliminary evaluation of safety margin as well as the intuitions to the design of the MRR. Input and modeling for the RELAP5/MOD3 simulations have also been described. The analysis results indicate that the concept of the MRR is feasible with practical safety margins. The same events have been also analyzed by using the PARET/ANL and the EUREKA-2/RR codes to compare the codes suitability, which have been widely used for the analysis of research reactors. Same geometric and modeling data used for the RELAP5/MOD3 have been used as long as they correspond to each code's input requirements. The three codes show the same or similar overall trends for the events analyzed, but show a small difference in a specific condition.

Journal Articles

Basic study on surface chemical combination between beryllium metal and hydrogen isotope gas, 2

Ito, Masayasu; Kitagishi, Shigeru; Hanawa, Yoshio; Tsuchiya, Kunihiko; Hatano, Yuji*; Matsuyama, Masao*; Nagasaka, Takuya*; Hishinuma, Yoshimitsu*

Annual Report of National Institute for Fusion Science; April 2011 - March 2012, P. 535, 2012/12

Beryllium has been utilized as a moderator and/or reflector in a number of material testing reactors. Beryllium is also supposed to be widely used in fusion reactors as neutron multiplier and protective walls of plasma facing components. It is important to perform the characterization of the different grade beryllium such as the productivity, mechanical and chemical properties and the interaction under water and/or gas environment. In this study, three kinds of beryllium (S-200F, S-65H, I-220H) were prepared, and corrosion test and surface analysis of these beryllium samples were carried out for life time expansion under pure water. As a result, the surface change of each Be sample was observed by the corrosion test and influenced by the content of BeO and the grain size.

Journal Articles

Neutron irradiation tests for beryllium material selection of neutron reflector in JMTR

Tsuchiya, Kunihiko; Ito, Masayasu; Kitagishi, Shigeru; Endo, Yasuichi; Saito, Takashi; Hanawa, Yoshio; Dorn, C. K.*

JAEA-Conf 2012-002, p.111 - 114, 2012/12

no abstracts in English

Journal Articles

Current status of a new polarized neutron reflectometer at the intense pulsed neutron source of the Materials and Life Science Experimental Facility (MLF) of J-PARC

Takeda, Masayasu; Yamazaki, Dai; Soyama, Kazuhiko; Maruyama, Ryuji; Hayashida, Hirotoshi; Asaoka, Hidehito; Yamazaki, Tatsuya; Kubota, Masato; Aizawa, Kazuya; Arai, Masatoshi; et al.

Chinese Journal of Physics, 50(2), p.161 - 170, 2012/04

JAEA Reports

Research of flaw assessment method for beryllium reflector elements

Shibata, Akira; Ito, Masayasu; Takemoto, Noriyuki; Nakatsuka, Masafumi*; Ohara, Hiroshi*; Kodama, Mitsuhiro*; Tanimoto, Masataka; Tsuchiya, Kunihiko

JAEA-Technology 2011-034, 67 Pages, 2012/02

JAEA-Technology-2011-034.pdf:6.94MB

Reflector elements made from metal beryllium is widely used as neutron reflectors to increase neutron flux in test reactors. When beryllium reflector elements are irradiated by neutron, bending of reflector elements caused by swelling occurs, and beryllium reflector elements must be replaced in several years. In this report, investigation for non-destructive inspection method of metal Beryllium and experiments for Preliminary inspection to establish post irradiation examination method for research of characteristics of metal beryllium under neutron irradiation were reported.

JAEA Reports

Conceptual design of multipurpose compact research reactor; Annual report FY2010 (Joint research)

Imaizumi, Tomomi; Miyauchi, Masaru; Ito, Masayasu; Watahiki, Shunsuke; Nagata, Hiroshi; Hanakawa, Hiroki; Naka, Michihiro; Kawamata, Kazuo; Yamaura, Takayuki; Ide, Hiroshi; et al.

JAEA-Technology 2011-031, 123 Pages, 2012/01

JAEA-Technology-2011-031.pdf:16.08MB

The number of research reactors in the world is decreasing because of their aging. However, the planning to introduce the nuclear power plants is increasing in Asian countries. In these Asian countries, the key issue is the human resource development for operation and management of nuclear power plants after constructed them, and also the necessity of research reactor, which is used for lifetime extension of LWRs, progress of the science and technology, expansion of industry use, human resources training and so on, is increasing. From above backgrounds, the Neutron Irradiation and Testing Reactor Center began to discuss basic concept of a multipurpose low-power research reactor for education and training, etc. This design study is expected to contribute not only to design tool improvement and human resources development in the Neutron Irradiation and Testing Reactor Center but also to maintain and upgrade the technology on research reactors in nuclear power-related companies. This report treats the activities of the working group from July 2010 to June 2011 on the multipurpose low-power research reactor in the Neutron Irradiation and Testing Reactor Center and nuclear power-related companies.

Journal Articles

Basic study on surface chemical combination between beryllium metal and hydrogen isotope gas

Tsuchiya, Kunihiko; Kitagishi, Shigeru; Ito, Masayasu; Hanawa, Yoshio; Hatano, Yuji*; Matsuyama, Masao*; Nagasaka, Takuya*; Hishinuma, Yoshimitsu*

Annual Report of National Institute for Fusion Science; April 2010 - March 2011, P. 545, 2011/11

no abstracts in English

JAEA Reports

Neutron shielding reinforcement in the JMTR hot laboratory

Ito, Masayasu; Kawamata, Kazuo; Tayama, Yoshinobu; Kanazawa, Yoshiharu; Yonekawa, Minoru; Nakagawa, Tetsuya; Omi, Masao; Iwamatsu, Shigemi

JAEA-Technology 2011-022, 44 Pages, 2011/07

JAEA-Technology-2011-022.pdf:3.29MB

Hot laboratory are facilities that execute the post irradiation examination of sample irradiated in material testing reactors etc. The handling of high burn-up fuel is scheduled in the JMTR (Japan Materials Testing Reactor) hot laboratory with JMTR re-operate in FY 2011. This report describes evaluation, production and installation of shielding of the hot cells in the JMTR hot laboratory.

Journal Articles

Event structure and double helicity asymmetry in jet production from polarized $$p + p$$ collisions at $$sqrt{s}$$ = 200 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Y.*; Al-Bataineh, H.*; Alexander, J.*; Aoki, K.*; Aphecetche, L.*; Armendariz, R.*; et al.

Physical Review D, 84(1), p.012006_1 - 012006_18, 2011/07

 Times Cited Count:23 Percentile:28.51(Astronomy & Astrophysics)

We report on the event structure and double helicity asymmetry ($$A_{LL}$$) of jet production in longitudinally polarized $$p + p$$ collisions at $$sqrt{s}$$ = 200 GeV. Photons and charged particles were measured by the PHENIX experiment. Event structure was compared with the results from PYTHIA event generator. The production rate of reconstructed jets is satisfactorily reproduced with the next-to-leading-order perturbative QCD calculation. We measured $$A_{LL}$$ = -0.0014 $$pm$$ 0.0037 at the lowest $$P_T$$ bin and -0.0181 $$pm$$ 0.0282 at the highest $$P_T$$ bin. The measured $$A_{LL}$$ is compared with the predictions that assume various $$Delta G(x)$$ distributions.

JAEA Reports

Investigation for methods of micro-structural observation of beryllium metals by TEM

Ito, Masayasu; Kawamata, Kazuo; Sozawa, Shizuo; Shibata, Akira; Tsuchiya, Kunihiko; Kitsunai, Yuji*; Kodama, Mitsuhiro*

JAEA-Testing 2011-003, 22 Pages, 2011/06

JAEA-Testing-2011-003.pdf:9.16MB

In JMTR, beryllium metal is used for neutron reflector. However, the periodical exchange of the neutron reflector is necessary due to degradation of strength and swelling under neutron irradiation. So it is required to select the material that bears long term from the viewpoint of the utilization rate improvement and the radioactive waste decrease in JMTR. It is important to evaluate the characteristics of beryllium metals precisely. This report describes the preparation method of the sample and observation results by the transmission electron microscope that is being examined as a evaluation method of the beryllium metal.

Journal Articles

Identified charged hadron production in $$p + p$$ collisions at $$sqrt{s}$$ = 200 and 62.4 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Armendariz, R.*; et al.

Physical Review C, 83(6), p.064903_1 - 064903_29, 2011/06

 Times Cited Count:144 Percentile:0.62(Physics, Nuclear)

Transverse momentum distributions and yields for $$pi^{pm}, K^{pm}, p$$, and $$bar{p}$$ in $$p + p$$ collisions at $$sqrt{s}$$ = 200 and 62.4 GeV at midrapidity are measured by the PHENIX experiment at the RHIC. We present the inverse slope parameter, mean transverse momentum, and yield per unit rapidity at each energy, and compare them to other measurements at different $$sqrt{s}$$ collisions. We also present the scaling properties such as $$m_T$$ and $$x_T$$ scaling and discuss the mechanism of the particle production in $$p + p$$ collisions. The measured spectra are compared to next-to-leading order perturbative QCD calculations.

Journal Articles

Azimuthal correlations of electrons from heavy-flavor decay with hadrons in $$p+p$$ and Au+Au collisions at $$sqrt{s_{NN}}$$ = 200 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Aramaki, Y.*; et al.

Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04

 Times Cited Count:8 Percentile:46.17(Physics, Nuclear)

Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled $$p+p$$ collisions. Here we extend these studies to two particle correlations where one particle is an electron from the decay of a heavy flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interaction between heavy quarks and the quark-gluon matter. We find the away-side-jet shape and yield to be modified in Au+Au collisions compared to $$p+p$$ collisions.

Journal Articles

Measurement of neutral mesons in $$p$$ + $$p$$ collisions at $$sqrt{s}$$ = 200 GeV and scaling properties of hadron production

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Y.*; Al-Bataineh, H.*; Alexander, J.*; Aoki, K.*; Aphecetche, L.*; Armendariz, R.*; et al.

Physical Review D, 83(5), p.052004_1 - 052004_26, 2011/03

 Times Cited Count:140 Percentile:1.52(Astronomy & Astrophysics)

The PHENIX experiment at RHIC has measured the invariant differential cross section for production of $$K^0_s$$, $$omega$$, $$eta'$$ and $$phi$$ mesons in $$p + p$$ collisions at $$sqrt{s}$$ = 200 GeV. The spectral shapes of all hadron transverse momentum distributions are well described by a Tsallis distribution functional form with only two parameters, $$n$$ and $$T$$, determining the high $$p_T$$ and characterizing the low $$p_T$$ regions for the spectra, respectively. The integrated invariant cross sections calculated from the fitted distributions are found to be consistent with existing measurements and with statistical model predictions.

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