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Murase, Kiyoka*; Kataoka, Ryuho*; Nishiyama, Takanori*; Nishimura, Koji*; Hashimoto, Taishi*; Tanaka, Yoshimasa*; Kadokura, Akira*; Tomikawa, Yoshihiro*; Tsutsumi, Masaki*; Ogawa, Yasunobu*; et al.
Journal of Space Weather and Space Climate (Internet), 12, p.18_1 - 18_16, 2022/06
Times Cited Count：1 Percentile：22.72(Astronomy & Astrophysics)We identified two energetic electron precipitation (EEP) events during the growth phase of moderate substorms and estimated the mesospheric ionization rate for an EEP event for which the most comprehensive dataset from ground-based and space-born instruments was available. The mesospheric ionization signature reached below 70 km altitude and continued for ~15 min until the substorm onset, as observed by the PANSY radar and imaging riometer at Syowa Station in the Antarctic region. We also used energetic electron flux observed by the Arase and POES 15 satellites as the input for the air-shower simulation code PHITS to quantitatively estimate the mesospheric ionization rate. Combining the cutting-edge observations and simulations, we shed new light on the space weather impact of the EEP events during geomagnetically quiet times, which is important to understand the possible link between the space environment and climate.
Kobayashi, Fuyumi; Sumiya, Masato; Kida, Takashi; Kokusen, Junya; Uchida, Shoji; Kaminaga, Jota; Oki, Keiichi; Fukaya, Hiroyuki; Sono, Hiroki
JAEA-Technology 2016-025, 42 Pages, 2016/11
JAEA-Technology-2016-025.pdf:17.88MB
A preliminary test on MOX fuel dissolution for the STACY critical experiments had been conducted in 2000 through 2003 at Nuclear Science Research Institute of JAEA. Accordingly, the uranyl / plutonium nitrate solution should be reconverted into oxide powder to store the fuel for a long period. For this storage, the moisture content in the oxide powder should be controlled from the viewpoint of criticality safety. The stabilization of uranium / plutonium solution was carried out under a precipitation process using ammonia or oxalic acid solution, and a calcination process using a sintering furnace. As a result of the stabilization operation, recovery rate was 95.6% for uranium and 95.0% for plutonium. Further, the recovered oxide powder was calcined again in nitrogen atmosphere and sealed immediately with a plastic bag to keep its moisture content low and to prevent from reabsorbing atmospheric moisture.
Shinoda, Yoshihiko; Tsuchida, Shoji*; Kimura, Hiroshi*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 13(3), p.94 - 112, 2014/09
Fukushima Daiichi Nuclear Power Plant accident (Fukushima accident) has brought about a great change in many people's perceptions about nuclear power plant safety. When discussing future energy options for Japan, it is important to have a full grasp of the attitude of a large number of people towards nuclear energy. The Atomic Energy Society of Japan has conducted annual questionnaire survey of 500 adults who live within 30 kilometers of Tokyo Station. The aim of this survey is to assess trends in public attitude towards nuclear energy. The authors that designed the questionnaire entries of this survey have been managing questionnaire data as members of the Data Management Working Group under the Social and Environmental Division of the Atomic Energy Society of Japan. We confirmed the change in public attitude towards nuclear energy through this periodical survey after the Fukushima accident. In particular, public concerns about the use of nuclear energy increased after the Fukushima accident, and many people have raised doubts over the use of nuclear energy in the future.
Shibata, Takanori; Koga, Shojiro*; Terasaki, Ryo*; Inoue, Takashi; Dairaku, Masayuki; Kashiwagi, Mieko; Taniguchi, Masaki; Tobari, Hiroyuki; Tsuchida, Kazuki; Umeda, Naotaka; et al.
Review of Scientific Instruments, 83(2), p.02A719_1 - 02A719_3, 2012/02
Times Cited Count：2 Percentile：12.31(Instruments & Instrumentation)In the NBI for large fusion devices, production of uniform negative ion beam is one of important issues. A physical model is proposed to understand the non-uniformity. It has been qualitatively shown that the non-uniform beam intensity is due to the following process; (1) formation of non-uniform EEDF, (2) localized production of hydrogen atoms/ions (H
/H
) due to (1), (3) non-uniform flux of H/H to the PG and (4) localized surface production of negative ions. However, in the past studies, the EEDF was assumed as two temperature Maxwellian distribution from measurements. Thus effects of high energy electrons are not taken into account precisely. In the present research, local EEDF is calculated by the 3D Monte-Carlo kinetic model which takes into account the spatial and magnetic configurations of the real negative ion source. The numerical result show that high energy component of the EEDF enhances the spatial non-uniformity in the production rate of H/H.
collisions at 
= 200 GeVAdare, 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：29 Percentile：72.31(Astronomy & Astrophysics)We report on the event structure and double helicity asymmetry (
) of jet production in longitudinally polarized collisions at = 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 = -0.0014 
0.0037 at the lowest 
bin and -0.0181 0.0282 at the highest bin. The measured is compared with the predictions that assume various 
distributions.
collisions at = 200 and 62.4 GeVAdare, 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：184 Percentile：99.44(Physics, Nuclear)Transverse momentum distributions and yields for 
, and 
in collisions at = 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 collisions. We also present the scaling properties such as 
and 
scaling and discuss the mechanism of the particle production in collisions. The measured spectra are compared to next-to-leading order perturbative QCD calculations.
and Au+Au collisions at 
= 200 GeVAdare, 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：49.7(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 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 collisions.
+ collisions at = 200 GeV and scaling properties of hadron productionAdare, 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：175 Percentile：98.48(Astronomy & Astrophysics)The PHENIX experiment at RHIC has measured the invariant differential cross section for production of 
, 
, 
and 
mesons in collisions at = 200 GeV. The spectral shapes of all hadron transverse momentum distributions are well described by a Tsallis distribution functional form with only two parameters, 
and 
, determining the high 
and characterizing the low 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.
Ishii, Junichi; Kobayashi, Fuyumi; Uchida, Shoji; Sumiya, Masato; Kida, Takashi; Shirahashi, Koichi; Umeda, Miki; Sakuraba, Koichi
JAEA-Technology 2009-068, 20 Pages, 2010/03
JAEA-Technology-2009-068.pdf:2.49MB
At Nuclear Fuel Cycle Safety Engineering Research Facility, the cerium mediated electrolytic oxidation method which is a decontamination technique to decrease the radioactivity of TRU wastes to the clearance-level has been developed for the effective reduction of TRU wastes generated from the decommissioning of a nuclear fuel reprocessing facility and so on. This method corrodes the oxide layer and the surface of metallic TRU metal wastes by the strong oxidation power of Ce
in nitric acid. In this study, parameter tests were conducted to optimize the solution condition of Ce
initial concentrations and nitric acid concentrations. The target corrosion rate of metallic TRU wastes set to be 2
4
m/h for the practical use of this method. Under the optimized solution condition, a dissolution test of stainless steel simulating wastes was carried out. From the result of the dissolution test, the average corrosion rate was 3.3 
m/h during the test time of 90 hours. Based on the supposition that the corrosion depth of metallic TRU wastes was 20 m enough to achieve the clearance-level, the treatment time for the decontamination was about 6 hours. It was confirmed from the result that the decontamination could be performed within one day and the decontamination solution could repeatedly reuse 15 times.
Motoki, Riyozo; Aoki, Hiromichi; Uchida, Shoji; Nagaishi, Ryuji; Yamada, Reiji
JAEA-Technology 2008-014, 23 Pages, 2008/03
JAEA-Technology-2008-014.pdf:9.05MB
The study of producing hydrogen with a Sr-90/Y-90 source is planned to utilze the radioactive waste effectively. Therefore we developed two methods of caking Sr-90 and a catalyst for the production of hydrogen effectively. One is a method of caking 
SrTiO
and TiO
in a silica gel. And another is a method of caking SrSO
and TiO in a silica gel. These solid matters are porous materials, which has a radiation resistant and chemical resistant. In addition, Y-90 which is a daughter nuclide of Sr-90 can be also used for hydrogen production.
Chikazawa, Yoshitaka; Nakagiri, Toshio; Konomura, Mamoru; Uchida, Shoji*; Tsuchiyama, Yoshihiko*
Nuclear Technology, 155(3), p.340 - 349, 2006/09
Times Cited Count：5 Percentile：36.38(Nuclear Science & Technology)Hydrogen production with a fast breeder reactor is attractive as a long term energy source with nuclear fuel breeding. The thermochemical and electrolytic hybrid process is one of the hydrogen production methods using sulfuric acid cycle with the maximum temperature 500
C which can be supplied by a sodium cooled fast breeder reactor. In this study, a hydrogen production plant with the thermochemical and electrolytic hybrid process has been designed and the hydrogen production efficiency has been evaluated. In the present concept, components in hydrogen production system are designed to be made of steels such as high Si cast iron which has good toughness against sulfuric acid. High hydrogen production efficiency of 44% (high heating value) is achieved assuming development of high efficiency electrolysis.
W/Re generatorsMatsuoka, Hiromitsu; Hashimoto, Kazuyuki; Hishinuma, Yukio*; Ishikawa, Koji*; Terunuma, Hitoshi*; Tatenuma, Katsuyoshi*; Uchida, Shoji*
Journal of Nuclear and Radiochemical Sciences, 6(3), p.189 - 191, 2005/12
Applicability of Mo adsorbent PZC(Poly Zirconium Compound) for W/Re generator was investigated. Long term stability of adsorption of W to the PZC column, elution of Re from PZC column, desorption of 
from PZC column, and labeling of Hydroxyethylidene Diphosphonic Acid(HEDP) and Mercaptoacetyltriglycine(MAG3) with Re eluted from PZC column were tested. The PZC generator gave reproducible Re elution yields with low W parent breakthrough for a long period of time(about 5 months), that is the W/Re generator using PZC has a potential for practical use.
Chikazawa, Yoshitaka; Konomura, Mamoru; Uchida, Shoji*; Sato, Hiroyuki*
Nuclear Technology, 152(3), p.266 - 272, 2005/12
Times Cited Count：22 Percentile：80.31(Nuclear Science & Technology)None
Chikazawa, Yoshitaka; Hori, Toru*; Konomura, Mamoru; Hori, Toru*; Uchida, Shoji*
Proceedings of 2005 International Congress on Advances in Nuclear Power Plants (ICAPP '05) (CD-ROM), 0 Pages, 2005/05
The thermochemical and electrolytic hybrid cycle is one of hydrogen production methods using sulfuric acid cycle. The maximum temperature in all of the processes is kept lower than 500C because electrolysis is partially utilized in the thermochemical process. In this study, a hydrogen production plant with the thermochemical and electrolytic hybrid cycle has been designed and the hydrogen production efficiency has been evaluated. In this design, components in hydrogen production system are designed to be made of steels such as high Si cast iron which has good toughness against sulfuric acid. High hydrogen production efficiency of 42% (high heating value) is achieved assuming development of high efficiency electrolysis.
Chikazawa, Yoshitaka; Hori, Toru; Konomura, Mamoru; Sato, Hiroyuki*; Uchida, Shoji*
Proceedings of 12th International Conference on Nuclear Engineering (ICONE-12) (CD-ROM), 49076 Pages, 2004/04
Focusing on the cover layer materials (as the Radon Barrier Materials), which could have the effect to restrain the radon from scattering into the air and the effect of the radiation shielding, we produced the radon barrier materials with crude bentonite on an experimental basis, using the rotary type comprehensive unit for grinding and mixing, through which we carried out the evaluation of the characteristics thereof.
Chikazawa, Yoshitaka; Hori, Toru; Konomura, Mamoru; Sato, Hiroyuki*; Uchida, Shoji*
Saikuru Kiko Giho, (22), p.19 - 25, 2004/00
In phase II of a feasibility study of JNC, we are finding a concept of a multi-purpose small sized reactor with various requirements, such as, economical competitiveness and safety. In the previous study, hydrogen production using hydrogen separation reformer was studied as one of promising concepts. In this study, a conceptual design study of a hydrogen and electric co-production plant has been done. The reactor thermal output is 375 MW and 25% of the thermal output is used for hydrogen production (70000 Nm
/h). The hydrogen production cost is estimated 21 yen/Nm that is higher than the economical goal of 17 yen/Nm. The major reason of the high cost is the large hydrogen separation reformer because of the limit of hydrogen separation efficiency of palladium membrane. The development of a new high efficiency hydrogen separation membrane is needed.
Lu via the 
Yb(n,
)Yb
Lu processHashimoto, Kazuyuki; Matsuoka, Hiromitsu; Uchida, Shoji*
Journal of Radioanalytical and Nuclear Chemistry, 255(3), p.575 - 579, 2003/03
Times Cited Count：42 Percentile：91.79(Chemistry, Analytical)The 
emitter Lu is a promising therapeutic radioisotope for the treatment of cancer. It has a half-life of 6.73 days and maximum energy of 498 keV, resulting in a short range of radiation in tissue. The decay is accompanied by the emission of low energy -radiation with 
= 208 keV (11.0%) and 113 keV (6.4%) suitable for simultaneous imaging. Lutetium-177 can be usually produced at nuclear reactors with high yield and high specific radioactivity by the Lu(n,)Lu reaction. However, radioisotopes with higher specific radioactivity are required in the field of radioimmunotherapy using labeled monoclonal antibodies. Thus, an alternative production route, namely the Yb(n,)Yb Lu process was studied to produce no-carrier-added (nca) Lu in this work. The radiochemical separation of the nca Lu from the macroscopic ytterbium target was investigated by means of reversed-phase ion-pair HPLC. The nca Lu was obtained in radiochemical pure form with a separation yield of 80%.
Nishihara, Tetsuo; Shimizu, Akira; Tanihira, Masanori*; Uchida, Shoji*
JAERI-Tech 2002-101, 46 Pages, 2003/01
no abstracts in English
Keutgen, N.; Matsuhashi, Shimpei; Mizuniwa, Chizuko; Ito, Takehito*; Fujimura, Takashi; Ishioka, Noriko; Watanabe, Satoshi; Sekine, Toshiaki; Uchida, Hiroshi*; Hashimoto, Shoji
Applied Radiation and Isotopes, 57(2), p.225 - 233, 2002/09
Times Cited Count：10 Percentile：54.86(Chemistry, Inorganic & Nuclear)no abstracts in English
Nishihara, Tetsuo; Muto, Yasushi; Uchida, Shoji*; Yoshioka, Naoki*
JAERI-Tech 2001-077, 44 Pages, 2001/12
JAERI-Tech-2001-077.pdf:2.16MB
JAERI has conducted the feasibility study of the HTGR gas turbine system from 1996 to 2000 sponsored by MEXT. This report concludes the safety criteria and rationalization of the safety items in the HTGR system.With respect to the safety criteria, the same value for the LWR is selected as the limit of radiation exposure. Probability of the design basis event (DBE) and beyond design basis event (BDBE) is set lower than those for the LWR to get higher safety margin. Adequate initial events and mitigation system are selected to consider the event sequence. The concept of the probability analysis is applied to identify DBEs and BDBEs. It is found that some safety items can be rationalized in consideration of the safety features of the HTGR. Finally, the safety class and design category of the items in the HGTR-GT are classified.
