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Journal Articles

Void reactivity evaluation by modified conversion ratio measurements in LWR critical experiments

Yoshioka, Kenichi*; Kikuchi, Tsukasa*; Gunji, Satoshi*; Kumanomido, Hironori*; Mitsuhashi, Ishi*; Umano, Takuya*; Yamaoka, Mitsuaki*; Okajima, Shigeaki; Fukushima, Masahiro; Nagaya, Yasunobu; et al.

Journal of Nuclear Science and Technology, 52(2), p.282 - 293, 2015/02

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

We have developed a void reactivity evaluation method by using modified conversion ratio measurements in a light water reactor (LWR) critical lattice. Assembly-wise void reactivity is evaluated from the "finite neutron multiplication factor", $$k^ast$$, deduced from the modified conversion ratio of each fuel rod. The distributions of modified conversion ratio and $$k^ast$$ on a reduced-moderation LWR lattice, for which the improvement of negative void reactivity is a serious issue, were measured. Measured values were analyzed with a continuous-energy Monte Carlo method. The measurements and analyses agreed within the measurement uncertainty. The developed method is useful for validating the nuclear design methodology concerning void reactivity.

Journal Articles

Verification and validation procedures of calculation codes for determining corrosive conditions in the BWR primary cooling system based on water radiolysis and mixed potential models

Uchida, Shunsuke*; Wada, Yoichi*; Yamamoto, Seiji*; Takagi, Junichi*; Hisamune, Kenji*

Journal of Nuclear Science and Technology, 51(1), p.24 - 36, 2014/01

 Times Cited Count:4 Percentile:55.17(Nuclear Science & Technology)

ECP in the BWR primary cooling system can be measured only in the restricted region. In order to determine ECP at any location, ECP should be evaluated by computer simulation codes consisting of water radiolysis models to determine the concentrations of corrosive radiolytic species and mixed potential models to determine ECP based on corrosive species. Mitigation of SCC crack growth rate due to decreasing ECP can be authorized by the JSME Standards, while mitigation of ECP due to hydrogen addition has not been authorized yet. In the paper, standard procedures to authorize the computer simulation codes based on the verification and validation method are proposed. The numerical justification of every code applied as a standard code should be verified and its accuracy and applicability for plant analysis should be validated. Benchmark problems for verification processes are proposed and comparison of the calculated results with the measured ones for the plant of evaluation is required.

Journal Articles

Effect of salt-containing filter paper attached to osmotic membrane

Sano, Kenji*; Yamada, Arisa*; Matsui, Akihiro*; Tsuji, Hideyuki*; Hasegawa, Shin; Sawada, Shinichi; Maekawa, Yasunari

Desalination, 324, p.34 - 36, 2013/09

 Times Cited Count:1 Percentile:100(Engineering, Chemical)

Anchored osmotic pressure inducer was examined. Salt-containing filter paper attached to an osmotic membrane increased the water flux to more than 10% at 1 MPa. The salt-containing filter paper was fabricated via graft polymerization of acrylic acid onto a filter paper followed by alkaline treatment. The filter paper was characterized by thermo gravimetric analysis (TGA), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), scanning electronic microscopy-energy dispersive X-ray spectrometry(SEM-EDS).

Journal Articles

Intra-pellet neutron flux distribution measurements in LWR critical lattices

Yoshioka, Kenichi*; Kikuchi, Tsukasa*; Gunji, Satoshi*; Kumanomido, Hironori*; Mitsuhashi, Ishi*; Umano, Takuya*; Yamaoka, Mitsuaki*; Okajima, Shigeaki; Fukushima, Masahiro; Nagaya, Yasunobu; et al.

Journal of Nuclear Science and Technology, 50(6), p.606 - 614, 2013/06

 Times Cited Count:1 Percentile:85.59(Nuclear Science & Technology)

We have developed an intra-pellet neutron flux and conversion ratio distribution measurement method. A foil activation method with special foils was used for the neutron flux distribution measurement. A $$gamma$$-ray spectrum analysis method with special collimators was used for the conversion ratio distribution measurement. Using the developed methods, intra-pellet neutron flux distributions and conversion ratio distributions were measured in critical experiments on a reduced-moderation LWR. Measured values were analyzed with a deterministic method and a Monte Carlo method. The neutron flux distribution measurements and analyses agreed within the range of 1% to 2%. The conversion ratio distribution measurements and analyses were consistent with each other. We found that the measurement methods are useful for the validation of neutron behavior in a fuel pellet, which is known as micro reactor physics.

Journal Articles

Outline of research and development of thermal-hydraulics and safety of Japanese Supercritical Water Cooled Reactor (JSCWR) project

Nakatsuka, Toru; Mori, Hideo*; Akiba, Miyuki*; Ezato, Koichiro; Yasuoka, Makoto*

Proceedings of 5th International Symposium on Supercritical Water-Cooled Reactors (ISSCWR-5) (CD-ROM), 12 Pages, 2011/03

In the thermal-hydraulic area of Japanese Supercritical Water Cooled Reactor (JSCWR) project, the main objective is to provide high-precision heat transfer and hydraulics resistance correlations of supercritical water which are necessary for the conceptual design of the core and fuel. For this purpose, a database was constructed from literature survey and previous research results. The most suitable correlation applied for circular tubes was selected based on the database and the range of application and predictive accuracy were defined. A thermal-hydraulics analysis code has been developed based on large eddy simulation, which is selected for simulation of the heat transfer deterioration, to give detailed information of thermal-hydraulics phenomena in a fuel bundle.

Journal Articles

Advanced orient cycle; Progress on fission product separation and utilization

Yamagishi, Isao; Ozawa, Masaki; Mimura, Hitoshi*; Kanamura, Shohei*; Mizuguchi, Koji*

Proceedings of 13th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2010) (CD-ROM), p.107 - 116, 2010/10

The present paper describes the progress on Fission Product (FP) separation in the Adv.-ORIENT (Advanced Optimization by Recycling Instructive Elements) cycle. The AMP-SG adsorbent (silica gel loaded with ammonium molybdophosphate) and CE-ALG microcapsule (alginate gel polymer enclosed with crown ether) were developed for separation of heat-generating elements, Cs and Sr, respectively. The AMP-SG adsorbed more than 99% of Cs from a simulated High-level Liquid Waste (HLLW). The CE-ALG adsorbed 0.0249 mmol/g of Sr. An electrodeposition is advantageous for both recovery and utilization of PGMs (Ru, Rh, Pd) and Tc. Pd was easily deposited on a Pt electrode. Reduction of Ru and Tc was accelerated in the presence of Pd or Rh. In the simulated HLLW, the redox reaction of Fe(III)/Fe(II) disturbed deposition of elements except for Pd. The deposit on Pt electrode from the simulated HLLW showed higher catalytic reactivity on electrolytic hydrogen production than that from solution containing only PGM.

Journal Articles

From waste to resource; Nuclear rare metals as a dream of modern alchemists

Koyama, Shinichi; Suzuki, Tatsuya*; Ozawa, Masaki

Energy Conversion and Management, 51(9), p.1799 - 1805, 2010/09

Journal Articles

Measured and simulated transport of 1.9 MeV laser-accelerated proton bunches through an integrated test beam line at 1 Hz

Nishiuchi, Mamiko; Sakaki, Hironao; Hori, Toshihiko; Bolton, P.; Ogura, Koichi; Sagisaka, Akito; Yogo, Akifumi; Mori, Michiaki; Orimo, Satoshi; Pirozhkov, A. S.; et al.

Physical Review Special Topics; Accelerators and Beams, 13(7), p.071304_1 - 071304_7, 2010/07

 Times Cited Count:25 Percentile:15.58(Physics, Nuclear)

A laser-driven repetition-rated 1.9 MeV proton beam line composed of permanent quadrupole magnets (PMQs), a radio frequency (rf) phase rotation cavity, and a tunable monochromator is developed to evaluate and to test the simulation of laser-accelerated proton beam transport through an integrated system for the first time. In addition, the proton spectral modulation and focusing behavior of the rf phase rotationcavity device is monitored with input from a PMQ triplet. In the 1.9 MeV region we observe very weakproton defocusing by the phase rotation cavity. The final transmitted bunch duration and transverse profile are well predicted by the PARMILA particle transport code. The transmitted proton beam duration of 6 ns corresponds to an energy spread near 5% for which the transport efficiency is simulated to be 10%. The predictive capability of PARMILA suggests that it can be useful in the design of future higher energy transport beam lines as part of an integrated laser-driven ion accelerator system.

Journal Articles

Laser-driven proton accelerator for medical application

Nishiuchi, Mamiko; Sakaki, Hironao; Hori, Toshihiko; Bolton, P.; Ogura, Koichi; Sagisaka, Akito; Yogo, Akifumi; Mori, Michiaki; Orimo, Satoshi; Pirozhkov, A. S.; et al.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.88 - 90, 2010/05

The concept of a compact ion particle accelerator has become attractive in view of recent progress in laser-driven ion acceleration. We report here the recent progress in the laser-driven proton beam transport at the Photo Medical Research Center (PMRC) at JAEA, which is established to address the challenge of laser-driven ion accelerator development for ion beam cancer therapy.

Journal Articles

Numerical simulations on turbulent heat transfer characteristics of supercritical pressure fluids

Nakatsuka, Toru; Takase, Kazuyuki; Yoshida, Hiroyuki; Misawa, Takeharu

Proceedings of 2009 ASME International Mechanical Engineering Congress & Exposition (IMECE 2009) (CD-ROM), 8 Pages, 2009/11

As one of next generation nuclear reactors, development of a supercritical pressure water reactor (SCWR) has been performed. In order to design the SCWR, it is necessary to investigate thermal-hydraulic characteristics in the SCWR core precisely. As for those characteristics, many experimental studies have been conducted from the former in each country using circular tubes, annular channels and the simulated fuel bundles. An objective of this study is to clarify the prediction accuracy of the turbulent heat transfer characteristics in the supercritical pressure fluids for the SCWR design. From the experimental results of the supercritical pressure fluids flowing upward in a vertical circular tube, it was confirmed that the turbulent heat transfer coefficient suddenly decreases under the high heat flux condition. Although many numerical studies have been done in order to confirm the deterioration of turbulent heat transfer in supercritical pressure fluids, it is important to choose a suitable turbulence model to obtain high prediction accuracy. Then, the prediction accuracy on the deteriorated turbulent heat transfer was investigated numerically using four kinds of turbulence models, SKE, MKE, RSM and LES. The predicted result of each turbulence model was compared with the experimental results of the concentric smooth annulus and vertical circular tube. From the results of the present study, it was found that LES is the most effective to simulate the deterioration of the turbulent heat transfer at the supercritical pressure fluids.

Journal Articles

Assessment of applicability of LES model for heat transfer deterioration

Nakatsuka, Toru; Yoshida, Hiroyuki; Takase, Kazuyuki

Nippon Kikai Gakkai 2009-Nendo Nenji Taikai Koen Rombunshu, Vol.3, p.141 - 142, 2009/09

In the thermal hydraulic design of supercritical water-cooled reactor, it is required to establish a design technique which can precisely predict heat transfer deterioration of supercritical water as the core coolant. The mechanism of heat transfer deterioration has not been figured out yet. In the present study, results of preliminary surveys on several turbulence models are reported. Large eddy simulation shows the most promising results for predictions of the heat transfer deterioration with a high accuracy.

Journal Articles

Adv.-ORIENT cycle; Its scientific progress and the engineering feasibility

Ozawa, Masaki; Suzuki, Tatsuya*; Koyama, Shinichi; Yamagishi, Isao; Fujita, Reiko*; Okada, Ken*; Tatenuma, Katsuyoshi*; Mimura, Hitoshi*; Fujii, Yasuhiko*

Proceedings of International Conference on Advanced Nuclear Fuel Cycle; Sustainable Options & Industrial Perspectives (Global 2009) (CD-ROM), p.1117 - 1126, 2009/09

Journal Articles

Focusing and spectral enhancement of a repetition-rated, laser-driven, divergent multi-MeV proton beam using permanent quadrupole magnets

Nishiuchi, Mamiko; Daito, Izuru; Ikegami, Masahiro; Daido, Hiroyuki; Mori, Michiaki; Orimo, Satoshi; Ogura, Koichi; Sagisaka, Akito; Yogo, Akifumi; Pirozhkov, A. S.; et al.

Applied Physics Letters, 94(6), p.061107_1 - 061107_3, 2009/02

 Times Cited Count:43 Percentile:14.2(Physics, Applied)

A pair of conventional permanent magnet quadrupoles is used to focus a 2.4 MeV laser-driven proton beam at a 1 Hz repetition rate. The magnetic field strengths are 55 T/m and 60 T/m for the first and second quadrupoles respectively. The proton beam is focused to a spot size (full width at half maximum) of 2.7$$times$$8 mm$$^{2}$$ at a distance of 650 mm from the source. This result is in good agreement with a Monte Carlo particle trajectory simulation.

Journal Articles

Development of a pyrochemical process in molten salts for treating radioactive waste from nuclear fuel cycle facilities

Fujita, Reiko*; Nakamura, Hitoshi*; Mizuguchi, Koji*; Utsunomiya, Kazuhiro*; Amamoto, Ippei

Proceedings of 2008 Joint Symposium on Molten Salts (USB Flash Drive), p.886 - 891, 2008/10

Pyrochemical treatment in molten salts is a promising process for decontamination of radioactive wastes without producing large amounts of secondary waste. In this report, the fundamental experiment was carried out to treat the wastes which had complicated shapes such as Magnoxend corps, metallic waste contaminated by uranium, spent chemical trap fillers and spent Zircaloy channel boxs from BWR and acquired good results.

JAEA Reports

Description of "Design guideline for gas entrainment prevention using CFD method" (Cooperative research)

Ohshima, Hiroyuki; Sakai, Takaaki; Kamide, Hideki; Kimura, Nobuyuki; Ezure, Toshiki; Uchibori, Akihiro; Ito, Kei; Kunugi, Tomoaki*; Okamoto, Koji*; Tanaka, Nobuatsu*; et al.

JAEA-Research 2008-049, 44 Pages, 2008/06


Japan Atomic Energy Agency has conducted a conceptional design study of a sodium-cooled fast reactor in a frame work of the FBR feasibility study. The plant system concept for a commercial step is intended to minimize a vessel diameter to achieve an economical competitiveness. Therefore, the coolant in the vessel has relatively higher velocity and gas entrainment (GE) prevention from a liquid surface in the reactor vessel becomes one of important issues for the thermal-hydraulic design. In order to establish a design criteria for the GE prevention, the GE from vortex dimples at the liquid surface was investigated by a working group. The 1st proposal of "Design Guideline for Gas Entrainment Prevention Using CFD Method" was established based on the knowledge gained from the working group activities. This report introduces each study in the working group to clarify the basis of the design guideline.

Journal Articles

Advanced ORIENT cycle, toward realizing intensified transmutation and utilization of radioactive wastes

Ozawa, Masaki; Koyama, Shinichi; Suzuki, Tatsuya*; Fujita, Reiko*; Mimura, Hitoshi*; Fujii, Yasuhiko*

Proceedings of International Conference on Advanced Nuclear Fuel Cycles and Systems (Global 2007) (CD-ROM), p.451 - 457, 2007/09

To minimize the ecological burden originating in nuclear fuel recycling, a new R&D strategy, Adv.-ORIENT (Advanced Optimization by Recycling Instructive ElemeNTs) cycle, was set forth. A key separation tool is ion exchange chromatography (IXC) by a tertiary pyridine resin having soft donor nitrogen atoms. This method has provided individual recovery of pure Am and Cm products with a Pu/U/Np fraction from irradiated fuel in just a 3-step separation. A catalytic electrolytic extraction (CEE) method by Pd$$_{adatom}$$ has been employed to separate, purify and fabricate RMFP catalysts. High separation efficiency of RMFP proved hydrochloric acid as a suitable media for their recovery. Different functioned ion exchangers, e.g., ammonium molybdophosphate (AMP), have been investigated for the separation of Cs$$^{+}$$. Theoretical and laboratory studies on the isotope separation of LLFPs were begun for $$^{79}$$Se, $$^{126}$$Sn and $$^{135}$$Cs.

Journal Articles

Vibro-packing experiment of non-spherical uranium dioxide particles with spherical metallic uranium particles

Matsuyama, Shinichiro*; Ishii, Katsunori; Hirai, Mutsumi*; Tsuboi, Yasushi*; Kihara, Yoshiyuki

Journal of Nuclear Science and Technology, 44(3), p.317 - 322, 2007/03

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

Japan Atomic Energy Agency has been developing vibro-packed fuel as one candidate for commercial fast breeder reactor fuels. In this study, vibro-packing experiments were carried out to investigate particle behavior during vibro-packing and particle distribution after vibro-packing in a cladding tube. Non-spherical uranium dioxide particles and spherical metallic uranium particles were used to simulate mixed oxide particles and oxygen getter particles. These experiments revealed that it is important to feed each size of fuel particles uniformly into a cladding tube without size segregation in order to obtain a vibro-packed fuel pin with oxygen getter particles uniformly dispersed. "Simultaneous feeding" with volumetric powder feeders is useful to obtain a vibro-packed fuel pin with oxygen getter particles uniformly dispersed.

Journal Articles

Development of the 170GHz gyrotron and equatorial launcher for ITER

Sakamoto, Keishi; Kasugai, Atsushi; Takahashi, Koji; Minami, Ryutaro*; Kariya, Tsuyoshi*; Mitsunaka, Yoshika*; Kobayashi, Noriyuki

Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 8 Pages, 2007/03

no abstracts in English

Journal Articles

High power and high efficiency operation of 170GHz gyrotron

Kasugai, Atsushi; Minami, Ryutaro*; Takahashi, Koji; Kobayashi, Noriyuki; Kariya, Tsuyoshi*; Mitsunaka, Yoshika*; Sakamoto, Keishi

Fusion Science and Technology, 51(2T), p.213 - 216, 2007/02

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

no abstracts in English

Journal Articles

Optimization of 28GHz gyrotron output performance for ECRH experiment of the GAMMA 10

Kariya, Tsuyoshi*; Mitsunaka, Yoshika*; Imai, Tsuyoshi*; Saito, Teruo*; Tatematsu, Yoshinori*; Sakamoto, Keishi; Minami, Ryutaro*; Watanabe, Osamu*; Numakura, Tomoharu*; Endo, Yoichi*

Fusion Science and Technology, 51(2T), p.397 - 399, 2007/02

 Times Cited Count:5 Percentile:58.15(Nuclear Science & Technology)

no abstracts in English

235 (Records 1-20 displayed on this page)