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JAEA Reports

Post-processor coding for large-scale transient simulation computer codes

Yoshikawa, Shinji

JAEA-Technology 2019-024, 22 Pages, 2020/03


In various technical fields of nuclear energy, computer codes are often used for transient simulations of target phenomena. Some of the codes were developed many years ago and have been revised with newly acquired findings, rather than newly developed, because of many encompassed numerical models and complexity of algorithms. In many cases, available outputs for users are output text files and graphs showing temporal variations of parameters, despite diversified and huge number of output information items are posing difficulty to the users in grasping the whole picture of the reproduced phenomena. This report compiles a series of know-hows in building a post-processor software for large simulation codes which serves as an interactive tool for code users in understanding the reproduced consequence with visually understandable information items. These know-hows are acquired through post-processor developments for LWR severe accident simulation codes RELAP/SCDAPSIM and MELCOR.

JAEA Reports

Inverse analysis of steam and hydrogen generation history of Fukushima Daiichi Nuclear Power Station unit 3

Yoshikawa, Shinji

JAEA-Research 2019-004, 32 Pages, 2019/09


Steam and hydrogen generation history and gas leakage area are inversely evaluated by a thermal hydraulic analysis code GOTHIC. The analyzed period in the accident progression is from the arrival of reactor liquid level at the top of active fuel (TAF) until start of depressurization of reactor pressure vessel(RPV) by activation of automatic depressurization system(ADS). Based on the measured behaviors of the RPV and PCV pressures from 6:30 of March 13th until the ADS activation, some leakage from RPV to PCV is supposed during this period. The leakage path and area are inversely derived on plural possible accident scenarios. The leakage area are estimated to be no greater than 1 cm$$^{2}$$. This result suggests that the gas flow at the time of the main slumping would have been through S/C, where vapor condensation was effective, thus certain contribution of non-condensable gases like hydrogen seems necessary to explain the observed D/W pressure increase.

Journal Articles

Progress of divertor simulation research toward the realization of detached plasma using a large tandem mirror device

Nakashima, Yosuke*; Takeda, Hisahito*; Ichimura, Kazuya*; Hosoi, Katsuhiro*; Oki, Kensuke*; Sakamoto, Mizuki*; Hirata, Mafumi*; Ichimura, Makoto*; Ikezoe, Ryuya*; Imai, Tsuyoshi*; et al.

Journal of Nuclear Materials, 463, p.537 - 540, 2015/08

 Times Cited Count:17 Percentile:7.48(Materials Science, Multidisciplinary)

Journal Articles

Development of divertor simulation research in the GAMMA 10/PDX tandem mirror

Nakashima, Yosuke*; Sakamoto, Mizuki*; Yoshikawa, Masayuki*; Oki, Kensuke*; Takeda, Hisahito*; Ichimura, Kazuya*; Hosoi, Katsuhiro*; Hirata, Mafumi*; Ichimura, Makoto*; Ikezoe, Ryuya*; et al.

Proceedings of 25th IAEA Fusion Energy Conference (FEC 2014) (CD-ROM), 8 Pages, 2014/10

Journal Articles

Trial visualization of fast reactor design knowledge

Yoshikawa, Shinji; Minami, Masaki*; Takahashi, Tadao*

Journal of Nuclear Science and Technology, 48(4), p.709 - 714, 2011/04

In design problems of large-scale systems like fast breeder reactors, inter-relations among design specifications are very important where a selected specification option is transferred to other specification selections as a premise to be taken account in engineering judgments. These inter-relations are also important in design case studies with hypothetical adoption of rejected design options for evaluation of deviation propagations among design specifications. Some of these rejected options have potential worth for future reconsideration by some circumstance changes (e.g., advanced simulations to exclude needs for mock-up tests, etc), to contribute for flexibility in system designs. In this study, a computer software is built to visualize design problem structure by representing engineering knowledge nodes on individual specification selections along with inter-relations of design specifications, to validate the knowledge representation method and to derive open problems.

Journal Articles

Thermal-hydraulic analysis of MONJU upper plenum under 40% rated power operational condition

Honda, Kei; Ohira, Hiroaki; Sotsu, Masutake; Yoshikawa, Shinji

Proceedings of 8th International Topical Meeting on Nuclear Thermal-Hydraulics, Operation and Safety (NUTHOS-8) (CD-ROM), 12 Pages, 2010/10

In this study, we calculated the thermal hydraulics of the upper plenum of MONJU by the detailed analysis model using commercial FVM code, FrontFlow/Red. The present analysis model simulates all structures with high resolution meshes. The 1st order upwind and 2nd order central difference scheme were applied to the advection and diffusion terms, respectively. And RNG $$k$$-$$epsilon$$ model was applied to turbulence modeling. These calculation results indicated that the structures installed in the plenum except for UIS did not affect largely to the temperature and velocity, the flow characteristics in the present results had similar tendencies with porous media approached applied to the UCS region and that the difference between the temperature measured in the UCS region and that of SA outlets is relatively small.

JAEA Reports

Nuclear Facilities Management Section Mutsu Office, Aomori Research and Development Center operations report; FY 2008

Nagane, Satoru; Matsuno, Satoru; Yamamoto, Makoto; Tobinai, Kazuhito; Ozaki, Shinji; Sato, Yasuo; Kitahara, Katsumi; Yoshikawa, Seiji

JAEA-Review 2009-018, 39 Pages, 2009/08


Nuclear Facilities Management Section is, Liquid nuclear waste facility, a small nuclear fuel treatment facility, operation, maintenance and decommissioning of the nuclear ship "MUTSU", which carried out the operation and maintenance services of solid waste facilities. This paper, the nuclear facilities Management Section, Office of FY2008 year (April 2008-March 2009) summarized results of operations.

Journal Articles

Hydrogen retention induced by ion implantation in tungsten trioxide films

Inoue, Aichi; Yamamoto, Shunya; Nagata, Shinji*; Yoshikawa, Masahito; Shikama, Tatsuo*

Nuclear Instruments and Methods in Physics Research B, 267(8-9), p.1480 - 1483, 2009/03

 Times Cited Count:9 Percentile:40.8(Instruments & Instrumentation)

We quantitatively studied the relation between hydrogen retention and optical properties induced by hydrogen ion implantation in tungsten trioxide (WO$$_{3}$$) films. Films of WO$$_{3}$$ (300 nm) covered with tungsten metal layers (200 nm) were prepared on transparent SiO$$_{2}$$ substrates by a reactive sputtering in Ar and O$$_{2}$$ mixture. When H$$_{2}$$$$^{+}$$ ions were implanted into the samples at an acceleration voltage of 10 kV, the concentration of hydrogen retaining in the WO$$_{3}$$ films increased up to 0.4 H/W in proportion to the fluence of H$$_{2}$$$$^{+}$$ ions. The optical absorption coefficient at 750 nm of samples increased linearly by 3 $$mu$$m$$^{-1}$$ with increasing the concentration of hydrogen implanted up to 0.1 H/W. And then, increased and saturated at 4 $$mu$$m$$^{-1}$$ with the increase of hydrogen concentration higher than 0.1 H/W. It was found that the hydrogen retention up to 0.1 H/W in tungsten trioxide layers can be monitored by measuring the optical absorbance.

JAEA Reports

Data description for coordinated research project on benchmark analyses of sodium natural convection in the upper plenum of the Monju reactor vessel under supervisory of Technical Working Group on Fast Reactors, International Atomic Energy Agency

Yoshikawa, Shinji; Minami, Masaki*

JAEA-Data/Code 2008-024, 28 Pages, 2009/01


A series of information required for numerical simulation of sodium thermal stratification observed at the plant trip test of "Monju" conducted in 1995 is provided, which consists of the test outline, geometry data of the reactor vessel upper plenum between the reactor core top and reactor outlet nozzles, and flow inlet boundary conditions at the reactor core top surface.

Journal Articles

Effects of catalyst on gasochromic properties in tungsten oxide films

Inoue, Aichi; Yamamoto, Shunya; Nagata, Shinji*; Yoshikawa, Masahito; Shikama, Tatsuo*

Transactions of the Materials Research Society of Japan, 33(4), p.1127 - 1130, 2008/12

We investigated effects of catalyst on gasochromic properties in tungsten oxide films. Amorphous WO$$_{3}$$ films coated with Pd and Pt catalysts were prepared on SiO$$_{2}$$ substrates by employing reactive RF magnetron sputtering. The field emission scanning electron microscope (FE-SEM) showed that particles with a dozes nm diameter of Pd and with a few nm of Pt grew on the surface at beginning of deposition. The continuous catalytic layers were observed with increasing the amounts of more than 2 nm for Pd and 0.2 nm for Pt catalysts, respectively. When the continuous layers formed on WO$$_{3}$$ surface, the excellent gasochromic properties were obtained. The results indicated that Pt catalysts were suitable for high sensitive hydrogen sensors consisting of gasochromic WO$$_{3}$$ films.

Journal Articles

Effects of composition and structure on hydrogen incorporation in tungsten oxide films deposited by sputtering

Inoue, Aichi; Yamamoto, Shunya; Nagata, Shinji*; Yoshikawa, Masahito; Shikama, Tatsuo*

Nuclear Instruments and Methods in Physics Research B, 266(15), p.3381 - 3386, 2008/08

 Times Cited Count:5 Percentile:58.28(Instruments & Instrumentation)

The effects of composition and structure on hydrogen incorporation property in tungsten oxide films were investigated. The tungsten oxide was deposited on carbon and SiO$$_{2}$$ substrates to form films by varying the temperature from 30 to 600 $$^{circ}$$C using a reactive sputtering in argon and oxygen mixture. We obtained amorphous structure in the films deposited below 400 $$^{circ}$$C and (0 1 0) oriented monoclinic WO$$_{3}$$ in the films deposited beyond 400 $$^{circ}$$C. Hydrogen concentration in the films increased from 0.1 to 0.7 H/W with changing the composition from WO$$_{0.25}$$ to WO$$_{3}$$. The hydrogen concentration in WO$$_{3}$$ films decreased to 0.4 H/W with increasing the substrate temperature during deposition. The Raman spectra of the WO$$_{3}$$ films revealed that decreasing of W$$^{6+}$$=O terminals was related to that of the hydrogen concentration. It was considered in detail that the incorporated hydrogen in tungsten oxide films was bonded at the end of W$$^{6+}$$=O terminals.

Journal Articles

Depositional records of plutonium and $$^{137}$$Cs released from Nagasaki atomic bomb in sediment of Nishiyama reservoir at Nagasaki

Kokubu, Yoko; Yasuda, Kenichiro; Magara, Masaaki; Miyamoto, Yutaka; Sakurai, Satoshi; Usuda, Shigekazu; Yamazaki, Hideo*; Yoshikawa, Shusaku*; Nagaoka, Shinji*; Mitamura, Muneki*; et al.

Journal of Environmental Radioactivity, 99(1), p.211 - 217, 2008/01

 Times Cited Count:14 Percentile:62.36(Environmental Sciences)

In a sediment core of Nishiyama reservoir at Nagasaki, depth profiles of $$^{240}$$Pu/$$^{239}$$Pu ratio, $$^{239+240}$$Pu and $$^{137}$$Cs concentrations were determined. Sediments containing plutonium and $$^{137}$$Cs, which were fallout deposited immediately after a detonation of Nagasaki atomic bomb, were identified in the core. Observed below the sediments were macroscopic charcoals, providing evidence for initial deposit of the fallout. This is the first entire depositional records of plutonium and $$^{137}$$Cs released from the Nagasaki atomic bomb together with those from atmospheric nuclear tests.

Journal Articles

Hydrogen behavior in gasochromic tungsten oxide films investigated by elastic recoil detection analysis

Inoue, Aichi; Yamamoto, Shunya; Nagata, Shinji*; Yoshikawa, Masahito; Shikama, Tatsuo*

Nuclear Instruments and Methods in Physics Research B, 266(2), p.301 - 307, 2008/01

 Times Cited Count:12 Percentile:31.78(Instruments & Instrumentation)

Changes in the composition and crystalline structure of gasochromic tungsten oxide films resulting from the incorporation of hydrogen were investigated. An uniaxial oriented films in the (0 1 0) plane of monoclinic WO$$_{3}$$ were obtained by reactive RF magnetron sputtering at 600 $$^{circ}$$C. The elastic recoil detection analysis for the films on glassy carbon revealed that the hydrogen impurity was uniformly distributed up to a concentration of 0.24 H/W. The Pd-coated films on SiO$$_{2}$$ turned to blue when they were exposed to a mixture of Ar and 5% H$$_{2}$$ gases. When the sample became colored, the hydrogen concentration in the film increased to 0.47 H/W and the crystalline structure of the film changed from monoclinic to tetragonal. These results indicated that the gasochromic coloration of the tungsten oxide films was accompanied by formation of hydrogen compounds called tungsten bronze (H$$_{x}$$ WO$$_{3}$$).

Journal Articles

Gasochromic properties of nanostructured tungsten oxide films prepared by sputtering deposition

Takano, Katsuyoshi; Inoue, Aichi; Yamamoto, Shunya; Sugimoto, Masaki; Yoshikawa, Masahito; Nagata, Shinji*

Japanese Journal of Applied Physics, Part 1, 46(9B), p.6315 - 6318, 2007/09

 Times Cited Count:7 Percentile:67.15(Physics, Applied)

The amorphous, polycrystalline, and oriented films of the tungsten oxide were fabricated by sputtering deposition. It is found that each film has different roughness in the surface. The films with rough surface show fast coloration in 1% hydrogen. There is possibility that the gasochromic properties are improved effectively by the control of the surface morphology, and the films with large grains on the surface have better gasochromic coloration.

Journal Articles

Gasochromic coloration of non-stoichiometric WO$$_{rm 3-x}$$ films

Inoue, Aichi; Yamamoto, Shunya; Nagata, Shinji*; Takano, Katsuyoshi; Yoshikawa, Masahito; Shikama, Tatsuo*

Transactions of the Materials Research Society of Japan, 32(1), p.107 - 110, 2007/03

We investigated the gasochromic coloration of amorphous tungsten oxide films having compositions between WO$$_{0.25}$$ and WO$$_{3.0}$$. The films were deposited on SiO$$_{2}$$ or glassy carbon substrates by the reactive radio frequency (r. f.) magnetron sputtering with varying oxygen partial pressure. The oxygen and hydrogen concentration of the tungsten oxide films were determined using the Rutherford Backscattering Spectrometry (RBS) and the Elastic Recoil Detection Analysis (ERDA), respectively. The optical transmission was examined for the films coated with palladium catalysis during the exposure of diluted hydrogen gas. Superior gasochromic properties were obtained for the films consisting of tungsten trioxide WO$$_{3}$$. For the films with lower oxygen concentration than WO$$_{3}$$, the optical transmission hardly changed during the hydrogen exposure. A large concentration of hydrogen about 0.7 per a tungsten atom was found in the WO$$_{3}$$ films. The hydrogen retention drastically decreased with a decrease of the oxygen concentration.

Journal Articles

Effects of hydrogen and hydroxyl on ion beam induced luminescence of ceramics

Nagata, Shinji*; Yamamoto, Shunya; Inoue, Aichi; Tsuchiya, Bun*; To, Kentaro*; Takano, Katsuyoshi; Yoshikawa, Masahito; Shikama, Tatsuo*

JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 148, 2007/02

no abstracts in English

Journal Articles

Blister formation in rutile TiO$$_{2}$$(100) films by helium irradiation

Yamamoto, Shunya; Nagata, Shinji*; Takeyama, Akinori; Yoshikawa, Masahito

Nuclear Instruments and Methods in Physics Research B, 249(1-2), p.374 - 376, 2006/08

 Times Cited Count:7 Percentile:50.16(Instruments & Instrumentation)

no abstracts in English

Journal Articles

Gasochromic property of oriented tungsten oxide thin films

Inoue, Aichi; Takano, Katsuyoshi; Yamamoto, Shunya; Yoshikawa, Masahito; Nagata, Shinji*

Transactions of the Materials Research Society of Japan, 31(1), p.227 - 230, 2006/03

no abstracts in English

Journal Articles

Structure of air-water two-phase flow in helically coiled tubes

Murai, Yuichi*; Yoshikawa, Shinji; Toda, Shinichi*; Ishikawa, Masaaki*; Yamamoto, Fujio*

Nuclear Engineering and Design, 236(1), p.94 - 106, 2006/01

 Times Cited Count:44 Percentile:4.7(Nuclear Science & Technology)

Air-water two-phase flow in helicallly coiled tube of 20mm in the internal diameter is investigated ezperimentally to elucidate the effect of centrifugal acceleration on the flow regime map and the local instantaneous flow structure. Three kinds of test tubes including a straight tube are used to compare the flow structure under turbulent flow condition. The superficial velocity up to 6 m/s is tested so that centrifugal Froude number covers a range from 0 to 3. The inter facial structure is visualized from two directions by a high-speed video system with a synchronized measurement of local pressure fluctuation. The results reveral that the flow transition line alters due to centrifugal force acting on liquid phase in the tube. Especially the bubbly fow regime is narrwed significantly. The pressure fluctuation amplitude gets large relatively to the average presure loww as void fraction increases. The Frequency spectra of the pressure fluctuation have plural peaks in the case of strong curvature, implying that the periodicity of slugging two-phase flow is collapsed by internal secondary flow actibated inside liquid phase. Moreover, the substantial velocity of gas phase is slower than the total superficial velocity in case of large Froude number because of biased distribution to the inner surface allowing liquid flow passing outside as like a radial stratified flow.

Journal Articles

Interlock systems for J-PARC LINAC

Sakaki, Hironao; Takahashi, Hiroki; Ishiyama, Tatsuya*; Kawase, Masato; Sako, Hiroyuki; Kato, Yuko; Ito, Yuichi; Yoshikawa, Hiroshi; Ueda, Shinji*; Suzuki, Takahiro*

Proceedings of 3rd Annual Meeting of Particle Accelerator Society of Japan and 31st Linear Accelerator Meeting in Japan (CD-ROM), p.367 - 369, 2006/00

This paper reports Personnel Interlock System, Machine Protection System, and other Interlock System in J-PARC LINAC. The noise measures is important in MPS, we describe the noise decreasing method. The number of accelerating particles in J-PARC LINAC that can be accelerated has been deciding by ministry's guideline. Therefore, it is necessary to do severe surveillance. Here we also explain this particle monitoring instrument.

121 (Records 1-20 displayed on this page)