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Journal Articles

Prototype manufacturing of small tritium target inside JAEA

Tanaka, Shigeru; Abe, Yuichi; Kawabe, Masaru; Kutsukake, Chuzo; Oginuma, Yoshikazu; Yamada, Masayuki; Suzuki, Takumi; Yamanishi, Toshihiko; Konno, Chikara

Journal of Plasma and Fusion Research SERIES, Vol.9, p.338 - 341, 2010/08

We have conducted a small tritium target production R&D for FNS inside JAEA. The tritium target is produced by adsorbing tritium in a thin titanium layer. Since titanium is very active to oxygen, glow discharge cleaning was carried out to remove an oxidation film of the titanium surface. Through many tests with deuterium, we found out that it was not an oxidation film but humidity to disturb tritium absorption. The following procedures were necessary; (1) to outgas the inside of an absorption chamber, (2) to keep environmental humidity under 3% in handling the titanium-deposited substrate, (3) to keep the titanium-deposited target substrate in the vacuum. The DT neutron generation performance of the tritium target produced with the above procedures was the same as that with discharge cleaning. The manufacture condition of the small target was established.

Journal Articles

Measurement of reaction rate distribution in partial mockups for the ITER TBM with DT neutrons

Sato, Satoshi; Takakura, Kosuke; Ochiai, Kentaro; Kondo, Keitaro; Tatebe, Yosuke; Onishi, Seiki; Wada, Masayuki*; Kutsukake, Chuzo; Tanaka, Shigeru; Abe, Yuichi; et al.

Fusion Science and Technology, 56(1), p.227 - 231, 2009/07

 Times Cited Count:1 Percentile:10.95(Nuclear Science & Technology)

Previously DT neutronics experiments were performed by using partial blanket mockups for Japanese ITER test blanket module at JAEA FNS, and tritium production rates (TPR) inside blanket mockups were measured in details. The calculation with the nuclear data library FENDL-2.1 and Monte Carlo code MCNP4C agreed well with most of the measured TPRs within uncertainty of 10%. On the other hand, overestimations were found for the TPR in the experiment with a reflector and the TPR around the boundary between the rear part of the breeder layer and the beryllium layer by more than 10%. In order to confirm this concern, we measured reaction rate distribution in the partial blanket mockups with DT neutrons with two solid breeder blanket partial mockups, (Be/Li$$_{2}$$TiO$$_{3}$$/Be, SS316/Li$$_{2}$$TiO$$_{3}$$/SS316). Experiments were performed with and without a neutron source reflector. In order to measure reaction rate distributions, the activation foil method was applied using Nb and Au foils in this study. Experimental analyses were performed by MCNP4C with FENDL-2.1. Calculation results to experimental ones (C/Es) on the Au reaction rate with a reflector were larger than those without one. Detailed results are presented in this conference.

Journal Articles

Positron annihilation lifetime measurements of vanadium alloy and F82H irradiated with fission and fusion neutrons

Sato, Koichi*; Inoue, Kazuya*; Yoshiie, Toshimasa*; Xu, Q.*; Wakai, Eiichi; Kutsukake, Chuzo; Ochiai, Kentaro

Journal of Nuclear Materials, 386-388, p.203 - 205, 2009/04

 Times Cited Count:2 Percentile:19.23(Materials Science, Multidisciplinary)

V-4Cr-4Ti F82H, Ni and Cu were irradiated with fission and fusion neutrons at room temperature and 473 K. Defect structures were analyzed and compared using positron annihilation lifetime measurement, and microstructural evolution was discussed. The mean lifetime of positrons (the total amount of residual defects) increased with the irradiation dose. The effect of cascade impact was detected in Ni at room temperature. The size and the number of vacancy clusters were not affected by the displacement rate in the fission neutron irradiation at 473 K for the metals studied. The vacancy clusters were not formed in V Cr Ti irradiated at 473 K in the range of 10$$^{-6}$$-10$$^{-3}$$ dpa. In F82H irradiated at 473 K, the defect evolution was prevented by pre-existing defects. The mean lifetime of positrons in fission neutron irradiation was longer than that in fusion neutron irradiation in V Cr Ti at 473 K. It was interpreted that more closely situated subcascades were formed in the fusion neutron irradiation and subcascades interacted with each other, and consequently the vacancy clusters did not grow larger.

JAEA Reports

Characterization of the DD-neutron source for the 80 degrees beam line of the Fusion Neutronics Source (FNS)

Kondo, Keitaro; Ochiai, Kentaro; Kutsukake, Chuzo; Konno, Chikara

JAEA-Technology 2008-088, 90 Pages, 2009/03

JAEA-Technology-2008-088.pdf:26.83MB

In order to utilize the d-D neutron source with a titanium deuteride target of the FNS facility for fusion neutronics researchs, the specification of the d-D neutron source was investigated. The characteristic of neutrons produced by the d-D reaction was described based on the reaction kinematics and the target assembly of the accelarator was detailedly modeled for the MCNP calculation. In order to validate the MCNP model, the angular distribution of the neutron strength was measured with the foil activation method. The measured reaction rates were well predicted by the MCNP calculation and the validity of the present model was confirmed. Based on the model, a MCNP source term was prepared for usual analysis calculations of experiments with DD neutrons.

Journal Articles

D-T neutron streaming experiment simulating narrow gaps in ITER equatorial port

Ochiai, Kentaro; Sato, Satoshi; Wada, Masayuki*; Iida, Hiromasa; Takakura, Kosuke; Kutsukake, Chuzo; Tanaka, Shigeru; Abe, Yuichi; Konno, Chikara

Fusion Engineering and Design, 83(10-12), p.1725 - 1728, 2008/12

 Times Cited Count:1 Percentile:10.92(Nuclear Science & Technology)

Under the ITER/ITA task, we have conducted the neutron streaming experiment simulating narrow and deep gaps at boundaries between ITER vacuum vessel and equatorial port plugs. Micro fission chambers and some activation foils were utilized to measure fission rates and reaction rates to evaluate the relative fast and slow neutron fluences along the gap in the experimental assembly. The MCNP4C, TORT and Attila codes were used for the experimental analysis. From comparing our measurements and calculations, the following facts were found: (1) In case of a such narrow and deep gap structure, the calculation with MCNP, TORT and ATTILA codes and FENDL-2.1 is sufficient to predict fast neutron field inside the gap.: (2) Angular quadrature set of upward biased U315 and last collided source calculation on TORT and Attila were very important technique for accurate estimation of neutron transport.

Journal Articles

Progress in neutronics studies for the water cooled pebble bed blanket

Nishitani, Takeo; Sato, Satoshi; Ochiai, Kentaro; Kutsukake, Chuzo; Tanaka, Shigeru; Abe, Yuichi; Konno, Chikara

Fusion Science and Technology, 52(4), p.791 - 795, 2007/11

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Neutronics experimental study on tritium production in solid breeder blanket mockup with neutron reflector

Sato, Satoshi; Verzilov, Y.*; Ochiai, Kentaro; Wada, Masayuki*; Kutsukake, Chuzo; Tanaka, Shigeru; Abe, Yuichi; Seki, Masakazu; Oginuma, Yoshikazu*; Kawabe, Masaru*; et al.

Journal of Nuclear Science and Technology, 44(4), p.657 - 663, 2007/04

 Times Cited Count:7 Percentile:49.85(Nuclear Science & Technology)

Neutronics experiments have been performed for the solid breeder blanket using a DT neutron source at the FNS facility in JAEA. We have applied the blanket mockup composed of two enriched Li$$_{2}$$TiO$$_{3}$$ and three beryllium layers, and measured the detailed spatial distribution of the tritium production rate (TPR) using enriched Li$$_{2}$$CO$$_{3}$$ pellets. TPRs in the pellets have been measured by a liquid scintillation counter. Experiments have been done under a condition with a neutron reflector surrounding the DT neutron source. Numerical simulations have been performed using the MCNP-4C with the FENDL-2.0 and JENDL-3.3. The ranges of ratios of calculation results to experimental ones (C/Es) are 0.97-1.17 concerning with local TPR, and 1.04-1.09 for the integrated tritium production. It is found that the total integrated tritium production, which corresponds to tritium breeding ratio, can be predicted within uncertainty of 10% using the Monte Carlo calculation code and latest nuclear data libraries.

Journal Articles

Surface analysis for the TFTR Armor tile exposed to D-T plasmas using nuclear technique

Kubota, Naoyoshi; Ochiai, Kentaro; Kutsukake, Chuzo; Hayashi, Takao; Shu, Wataru; Kondo, Keitaro; Verzilov, Y.*; Sato, Satoshi; Yamauchi, Michinori; Nishi, Masataka; et al.

Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 7 Pages, 2007/03

Fuel and impurity particles show complicated behavior on the surface of plasma facing components (PFC) in fusion devices. The study is important for the design of the fuel recycling, safety management of the tritium inventory, etc. Quantitative measurements of hydrogen and lithium isotopes together with other impurities on the PFC surface exposed to D-T plasmas in TFTR were performed using the deuteron-induced nuclear reaction analysis, imaging plate method, full combustion method and activation analysis. The tritium depth profile was different from deuterium one. The surface tritium largely contributed to the whole tritium in the sample. On the other hand, the retained amount of lithium-6 was lager than that of lithium-7. This relates to the injection of enriched lithium-6 pellets in some campaigns. No other impurities were detected. So the large amount of tritium remained near the surface and did not diffuse more deeply, which gives a bright prospect for tritium safety.

Journal Articles

Ion and neutron beam analyses of hydrogen isotopes

Kubota, Naoyoshi; Ochiai, Kentaro; Kutsukake, Chuzo; Kondo, Keitaro*; Shu, Wataru; Nishi, Masataka; Nishitani, Takeo

Fusion Engineering and Design, 81(1-7), p.227 - 231, 2006/02

 Times Cited Count:5 Percentile:38.34(Nuclear Science & Technology)

Hydrogen isotopes play important roles in the fuel recycling, the plasma condition etc. at the surface region of plasma facing components. The Fusion Neutronics Source (FNS) of Japan Atomic Energy Research Institute has started microanalysis studies for fusion components since 2002 by applying the beam analyses. In this study, we have measured tritium depth profiles of TFTR tiles exposed to the deuterium-tritium plasma to reveal the hydrogen isotope behavior at the surface region using some microscopic techniques for material analyses at FNS. As the result of the deuteron nuclear reaction analysis, four kinds of elements; deuterium, tritium, lithium-6 and lithium-7, were identified from the energy spectra. Using the spectra, depth profiles of each element were also calculated. The tritium profile had a peak at 0.5 micron, whereas the deuterium and lithium profiles were uniform from the surface to 1.0 micron depth. In addition, the surface region of the TFTR tile has retained the tritium more than one order of magnitude in the bulk.

Journal Articles

Development of a new fusion power monitor based on activation of flowing water

Verzilov, Y. M.; Nishitani, Takeo; Ochiai, Kentaro; Kutsukake, Chuzo; Abe, Yuichi

Fusion Engineering and Design, 81(8-14), p.1477 - 1483, 2006/02

 Times Cited Count:2 Percentile:18.25(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Deuterium depth profiling in JT-60U W-shaped divertor tiles by nuclear reaction analysis

Hayashi, Takao; Ochiai, Kentaro; Masaki, Kei; Goto, Yoshitaka*; Kutsukake, Chuzo; Arai, Takashi; Nishitani, Takeo; Miya, Naoyuki

Journal of Nuclear Materials, 349(1-2), p.6 - 16, 2006/02

 Times Cited Count:10 Percentile:59.81(Materials Science, Multidisciplinary)

Deuterium concentrations and depth profiles in plasma-facing graphite tiles used in the divertor of JT-60U were investigated by NRA. The highest deuterium concentration of D/$$^{12}$$C of 0.053 was found in the outer dome wing tile, where the deuterium accumulated probably through the deuterium-carbon co-deposition. In the outer and inner divertor target tiles, the D/$$^{12}$$C data were lower than 0.006. Additionally, the maximum (H+D)/$$^{12}$$C in the dome top tile was estimated to be 0.023 from the results of NRA and SIMS. OFMC simulation showed energetic deuterons caused by NBI were implanted into the dome region with high heat flux. Furthermore, the surface temperature and conditions such as deposition and erosion significantly influenced the accumulation process of deuterium. The deuterium depth profile, SEM observation and OFMC simulation indicated the deuterium was considered to accumulate through three processes: the deuterium-carbon co-deposition, the implantation of energetic deuterons and the deuterium diffusion into the bulk.

Journal Articles

Depth profile measurements of hydrogen isotopes near the surface of the TFTR plasma facing component using nuclear reaction analysis

Kubota, Naoyoshi; Ochiai, Kentaro; Kutsukake, Chuzo; Hayashi, Takao; Shu, Wataru; Nishi, Masataka; Nishitani, Takeo

Purazuma, Kaku Yugo Gakkai-Shi, 81(4), p.296 - 301, 2005/04

no abstracts in English

Journal Articles

Measurement of deuterium and tritium retentions on the surface of JT-60 divertor tiles by means of nuclear reaction analysis

Ochiai, Kentaro; Hayashi, Takao; Kutsukake, Chuzo; Goto, Yoshitaka*; Masaki, Kei; Arai, Takashi; Miya, Naoyuki; Nishitani, Takeo

Journal of Nuclear Materials, 329-333(Part1), p.836 - 839, 2004/08

 Times Cited Count:4 Percentile:30.82(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Measurement of radiation skyshine with D-T neutron source

Yoshida, Shigeo*; Nishitani, Takeo; Ochiai, Kentaro; Kaneko, Junichi*; Hori, Junichi; Sato, Satoshi; Yamauchi, Michinori*; Tanaka, Ryohei*; Nakao, Makoto*; Wada, Masayuki*; et al.

Fusion Engineering and Design, 69(1-4), p.637 - 641, 2003/09

 Times Cited Count:7 Percentile:47.54(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Tritium distribution measurement of FNS tritium targets by imaging plate

Kutsukake, Chuzo; Seki, Masakazu; Tanaka, Shigeru; Oginuma, Yoshikazu*; Abe, Yuichi; Yamauchi, Michinori*

Fusion Science and Technology, 41(3), p.555 - 559, 2002/05

no abstracts in English

Journal Articles

Oral presentation

ITER/TBM neutronics experiments at FNS, 1; Experiment

Ochiai, Kentaro; Sato, Satoshi; Takakura, Kosuke; Yamauchi, Michinori*; Kutsukake, Chuzo; Tanaka, Shigeru; Abe, Yuichi; Seki, Masakazu; Kawabe, Masaru*; Konno, Chikara; et al.

no journal, , 

The test blanket module (TBM), water cooled pebble bed type, which is to be installed in ITER has been designed in JAEA. The TBM is made up of water cooling system with a kind of low activation ferrite, beryllium as neutron breeder, $$^{6}$$Li enriched Li$$_{2}$$TiO$$_{3}$$ or Li$$_{2}$$O pebble as tritium breeding material. To evaluate the nuclear properties, we have carried out some DT neutronics experiments with TBM mock up assemblies in the Fusion Neutronics Source (FNS) and one of the TBM nuclear properties, the tritium production rate (TPR), in the Li$$_{2}$$TiO$$_{3}$$ layer has been clarified by means of a liquid scintillation counter method with Li$$_{2}$$CO$$_{3}$$ pellets or Li$$_{2}$$O pebbles.

Oral presentation

Progress on blanket neutronics study

Sato, Satoshi; Takakura, Kosuke; Ochiai, Kentaro; Wada, Masayuki*; Onishi, Seiki; Iida, Hiromasa; Kutsukake, Chuzo; Tanaka, Shigeru; Abe, Yuichi; Kawabe, Masaru; et al.

no journal, , 

no abstracts in English

Oral presentation

Manufacturing of small tritium target for DT neutron generator

Kutsukake, Chuzo; Tanaka, Shigeru; Abe, Yuichi; Kawabe, Masaru*; Suzuki, Takumi; Yamada, Masayuki; Yamanishi, Toshihiko; Konno, Chikara

no journal, , 

A small tritium target for Fusion Neutronics Source(FNS) was successfully produced at the Tritium Processing Laboratory(TPL) in JAEA for the first time and examined the performance of the target. The small tritium target is produced with absorbing tritium in evaporated titanium layer on copper alloy substrate. Titanium metal is very active to oxygen. The surface of titanium quickly oxidizes on exposure to air and the oxidized titanium does not absorb enough tritium. Trough many tests we found out that a glow discharge cleaning system with argon gas could remove the oxidizes titanium surface adequately. Tritium amount of about 400 GBq was successfully absorbed to the cleaned titanium layer at TPL. The produced tritium target performance was tested at FNS. The tritium distribution in titanium was almost flat, the initial DT neutron generation rate was 1.7E11 n/s/mA and the attenuation of DT neutron generation rate with beam irradiation quantity was small.

Oral presentation

The Production of a tritium target for FNS

Tanaka, Shigeru; Kutsukake, Chuzo; Abe, Yuichi; Kawabe, Masaru*; Suzuki, Takumi; Yamada, Masayuki; Yamanishi, Toshihiko; Konno, Chikara

no journal, , 

no abstracts in English

22 (Records 1-20 displayed on this page)