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Journal Articles

Successful visualization of internal structures of reactor core in the HTTR; Non-destructive inspection by cosmic-ray muon radiography

Takamatsu, Kuniyoshi

Hihakai Kensa, 65(5), p.207 - 210, 2016/05

JP, 2010-166333   Patent publication (In Japanese)

In our study, we focused on a nondestructive inspection method by cosmic-ray muons which could be used to observe the internal reactor from outside the RPV and the CV. We conducted an observation test on the HTTR to evaluate the applicability of the method to the internal visualization of a reactor. We also analytically evaluated the resolution of existing muon telescopes to assess their suitability for the HTTR observation, and were able to detect the major structures of the HTTR based on the distribution of the surface densities calculated from the coincidences measured by the telescopes. Our findings suggested that existing muon telescopes could be used for muon observation of the internal reactor from outside the RPV and CV.

Journal Articles

Current status and future prospects of industrial application for the neutron, Neutron radiography

Matsubayashi, Masahito; Kawabata, Yuji*

Hoshasen To Sangyo, (107), p.4 - 15, 2005/09

no abstracts in English

Journal Articles

Non-Distructive Testing of Target Plate Model for Fusion Experimental Reactor by Neutron Radiography

Ishiyama, Shintaro; Matsubayashi, Masahito; Akiba, Masato

Nippon Genshiryoku Gakkai Wabun Rombunshi, 1(4), p.439 - 448, 2002/12

no abstracts in English

Journal Articles

Economic scale of utilization of radiation, 1; Industry: Comparison between Japan and the U. S. A.

Makuuchi, Keizo; Tagawa, Seiichi*; Kashiwagi, Masayuki*; Kamada, Toshimitsu*; Sekiguchi, Masayuki*; Hosobuchi, Kazunari*; Tominaga, Hiroshi*; Ooka, Norikazu

Journal of Nuclear Science and Technology, 39(9), p.1002 - 1007, 2002/09

 Times Cited Count:3 Percentile:73.46(Nuclear Science & Technology)

no abstracts in English

Journal Articles

The Method for decrease of helium gas leak with O-ring rubber gasket

Oba, Toshihiro; Inoue, Hiromi*; Kikuchi, Taiji; Taka, Isamu; Chiba, Masaaki; Ishikawa, Kazuyoshi; Tsuda, Kazumi*; Takeyama, Tomonori; Isozaki, Futoshi*; Terunuma, Isao*; et al.

NIFS-MEMO-36, p.121 - 124, 2002/06

no abstracts in English

Journal Articles

Latest instruments for neutron imaging and recent research results

Matsubayashi, Masahito

Hihakai Kensa No Saizensen (CD-ROM), 7 Pages, 2002/00

no abstracts in English

Journal Articles

Manufacturing and maintenance technologies developed for a thick-wall structure of the ITER vacuum vessel

Onozuka, Masanori*; Alfile, J. P.*; Aubert, P.*; Dagenais, J.-F.*; Grebennikov, D.*; Ioki, Kimihiro*; Jones, L.*; Koizumi, Koichi; Krylov, V.*; Maslakowski, J.*; et al.

Fusion Engineering and Design, 55(4), p.397 - 410, 2001/09

 Times Cited Count:17 Percentile:20.85

Development of welding, cutting and non-destructive testing (NDT) techniques, and development of remotized systems, have been conducted for on-site manufacturing and maintenance of the thick wall structure of the ITER vacuum vessel (VV). Conventional techniques, including TIG (tungsten inert gas) welding, plasma cutting and ultrasonic inspection, have been improved and optimized for the application to thick austenitic stainless steel plates. In addition, advanced methods have been investigated including reduced-pressure electron-beam and multi-pass NdYAG (neodymium-doped yttrium aluminum garnet) laser welding, NdYAG laser cutting, and EMAT (electro-magnetic acoustic transducer) inspection to improve cost and technical performance. Two types of remotized systems with different payloads have been investigated and one of them has been fabricated and demonstrated in field joint welding, cutting, and NDT tests on test mockups and full-scale ITER VV sector models. The progress and results of this development to date provide a high level of confidence that the manufacturing and maintenance of the ITER VV is feasible.

Journal Articles

Ultrasonic non-destractive testing on CFC monoblock divertor mock-up

Ezato, Koichiro; Taniguchi, Masaki; Sato, Kazuyoshi; Araki, Masanori; Akiba, Masato

Physica Scripta, T91, p.110 - 112, 2001/07

 Times Cited Count:1 Percentile:86.18(Physics, Multidisciplinary)

no abstracts in English

Journal Articles

Aging degradation of light water reactor materials; Reactor internal and pressure vessel materials

Tsukada, Takashi; Ebine, Noriya

Nippon AEM Gakkai-Shi, 9(2), p.171 - 177, 2001/06

no abstracts in English

JAEA Reports

Long-term durability test of acid recovery evaporators made of Ti-5% Ta aIloy and zirconium

; *; *; ; Koyama, Tomozo

JNC-TN8410 2001-013, 255 Pages, 2001/05

JNC-TN8410-2001-013.pdf:24.24MB

Mock-ups of acid recovery evaporators which are made of Ti-5% Ta alloy and Zr were tested under inactive condition for forty thousands hours to improve a corrosion resistance of acid recovery evaporator in Tokai reprocessing plant (TRP). The mock-up unit was designed and produced referring to the specification of acid recovery evaporator in TRP and the evaporation performance of the mock-up was 1/27 of TRP. A long-term durability of both evaporators was demonstrated by results of operation data, evaporation performance and corrosion resistance. The mock-up unit did not suffer from any trouble during the running test and the operation data such as temperature, flow, concentrations of nitric acid and metal ions were fairly stable within standard condition. As for the corrosion resistance, cracks and local corrosion such as intergranular attack were not observed on both evaporators after the running test, and a corrosion of weld was not selective. The average corrosion rates at measuring points were less than 0.1mm/yr, respectively, however, thickness of the Ti-5% Ta alloy evaporator was slightly reduced at all points of vapor phase region. In addition, from the result by test coupon, it is found that both materials have low susceptibility to stress corrosion cracking in this environment. The destructive inspection showed that the mechanical properties of both materials were not degraded during the running test. Finally, the total running time of the mock-up unit is much more than a maximum running time of acid recovery evaporator made of stainless steel in TRP (nearly 15,000 hours). On the basis of the test results, an excellent durability of Ti-5% Ta alloy and Zr evaporators under was successfully demonstrated throughout the mock-up test from an engineering perspective.

JAEA Reports

None

*

JNC-TN1400 2000-006, 68 Pages, 2000/07

JNC-TN1400-2000-006.pdf:2.18MB

no abstracts in English

JAEA Reports

None

*

JNC-TN1400 2000-004, 0 Pages, 2000/07

JNC-TN1400-2000-004.pdf:4.27MB

None

JAEA Reports

None

*; *; ; Aoto, Kazumi

JNC-TY9400 2000-010, 138 Pages, 2000/03

JNC-TY9400-2000-010.pdf:5.15MB

None

JAEA Reports

Enhancement of Nondestructive Evaluation Technique for Magnetic and Nonmagnetic Structural Components

JNC-TN9400 2000-021, 104 Pages, 2000/03

JNC-TN9400-2000-021.pdf:5.21MB

ln this report, research works performed in the Structura1 Safety Engineering Group of OEC/JNC are summarized as the final report of the doctoral fellowship. The main objective of this study is for the enhancement of the nondestructive evaluation techniques for structural components of both magnetic and nonmagnetic material. Studies in three topics have been carried out aiming at the quantitative evaluation of crack with the eddy current testing and the validation of a natural magnetic field based NDE method for detecting mechanical damages in a paramagnetic material. ln the first part of the study, an approach to the reconstruction of the natural crack was proposed and implemented with an idealized crack model for its validation. ln the second part, the correlation of the natural magnetization and the mechanical damages in the SUS304 stainless steel was investigated by using an experimental approach. ln part 3, an inverse method of the measured magnetic fields is proposed for the reconstruction of magnetic charges in the inspected material by using an optimization method and wavalet. As the first work, an approach to the reconstruction of an idealized natural crack of non-vanishing conductivity is proposed with use of signals of eddy current testing. Two numerical models are introduced at first for modeling the natural crack in order to represented it with a set of crack parameters. A method for the rapid prediction of the eddy current testing signals coming from these idealized cracks is given then by extending a knowledge based fast forward solver to the case of a non-vanishing conductivity. Based on this fast forward solver, the inverse algorithm of conjugate gradient method is updated to identify the crack parameters. Several examples are presented finally as a validation of the proposed strategy. The results show that both the two numerical models can give reasonable reconstruction results for signal of low noise. The model concerning the touch of ...

JAEA Reports

Damage evaluation of vessel model under thermal transient loading; Detection of damage by wavelet analysis for ultrasonic waveform

; *

JNC-TN9400 2000-018, 37 Pages, 2000/03

JNC-TN9400-2000-018.pdf:1.34MB

The damage evaluation for the vessel model on the cyclic thermal transient loading in sodium were performed by the ultrasonic detection method. The wavelet analysis that was an analysis method of the waveform was applied to detect the micro damage before a sign of the crack initiation. The time-frequency analysis by the wavelet transform was performed to evaluate the ultrasonic parameter for the micro damage. As the results, the ultrasonic echo was analyzed by some mother wavelet, and Gabor wavelet was reasonable. The analysis of ultrasonic echo by Gabor wavelet showed drop of the sound velocity at higher frequency than the peak frequency because of attenuation in the high frequency component. The difference of the peak frequency △fp between B1 and B2 echoes increased with the amount of damage, and △ fp was available as a parameter for the micro damage detection. The correlation between the sound velocity and the micro hardness for the amount of damage was also found, and each method suggested to available alternately. ln this study, it was indicated that an ultrasonic wave characteristic value that can detect damaged state before crack initiation was obtained from the wavelet analysis.

JAEA Reports

Report of lower endplug welding, and testing and inspecting result for MONJU 1$$^{st}$$ reload core fuel assembly

; ; ; *; *; *; *

JNC-TN8440 2000-008, 34 Pages, 2000/02

JNC-TN8440-2000-008.pdf:2.13MB

The procedure and result of lower endplug welding, Test and Inspection and Shipment of the 1$$^{st}$$ reload core fuel assembly (80 Fuel Assemblies) for the fast breeder reactor MONJU should be report, which had examined and inspected in Tamatsukuri Branch, Material Insurance office, Quality Assurance Section, Technical Administration Division, Plutonium Fuel Center (before: Inspection Section, Plutonium Fuel Division), from June 1994 to January 1996. The number of cladding tubes welded to the endplug were total to 13,804, 7,418 for Core - Inside of 43 fuel Assemblies and 6,386 for Core-Outside of 37 fuel Assemblies. 13,794 of them, 7,414 Core-Inside and 6,379 Core-Outside were approved by the test and sent to Plutonium Fuel Center. 10 of them weren't approved mainly because of default welding. Disapproval rating is 0.07%.

JAEA Reports

Trial manufacturing of titanium-carbon steel composite overpack

*; *; Tanai, Kenji

JNC-TN8400 99-048, 85 Pages, 1999/11

JNC-TN8400-99-048.pdf:4.31MB

This paper reports the results of design analysis and trial manufacturing of full-scale titanium-carbon steel composite overpacks. The overpack is one of the key components of the engineered barrier system, hence, it is necessary to confirm the applicability of current technique in their manufacture. The required thickness was calculated according to mechanical resistance analysis, based on models used in current nuclear facilities. The Adequacy of the calculated dimensions was confirmed by finite-element methods. To investigate the necessity of a radiation shielding function of the overpack, the irradiation from vitrified waste has been calculated. As a result, it was shown that shielding on handling and transport equipment is a more reasonable and practical approach than to increase thickness of overpack to attain a self-shielding capability. After the above investigation, trial manufacturing of full-scale model of titanium-carbon steel composite overpack has been carried out. For corrosion-resistant material, ASTM Grade-2 titanium was selected. The titanium layer was bonded individually to a cylindrical shell and flat cover plates (top and bottom) made of carbon steel. For the cylindrical shell portion, a cylindrically formed titanium layer was fitted to the inner carbon steel vessel by shrinkage. For the flat cover plates (top and bottom), titanium plate material was coated by explosive bonding. Electron beam welding and gas metal arc welding were combined to weld of the cover plates to the body. No significant failure was evident from inspections of the fabrication process, and the applicability of current technology for manufacturing titanium-carbon steel composite overpack was confirmed. Future research and development items regarding titanium-carbon steel composite overpacks are also discussed.

Journal Articles

Neutron and $$gamma$$ ray radiography using a multi-color converter

Iwata, Hideki*; Mochiki, Koichi*; Murata, Yutaka*; Nitto, Koichi*; Tamura, Toshiyuki*; Kobayashi, Hisao*; Matsubayashi, Masahito

Dai-3-Kai Hoshasen Ni Yoru Hihakai Hyoka Shimpojiumu Koen Rombunshu, p.142 - 147, 1999/11

no abstracts in English

JAEA Reports

An Approach to Reconstruction of a Natural Crack using Signals of Eddy Current Testing, 1; Reconstruction of an Idealized Crack

JNC-TN9400 99-009, 39 Pages, 1998/12

JNC-TN9400-99-009.pdf:1.12MB

In this paper, an approach to the reconstruction of an idealized natural crack of non-vanishing conductivity is proposed with use of signals of eddy current testing. Two numerical models are introduced at first for modeling a Stress Corrosion Crack (SCC) in order it possibly to be represented by a set of crack parameters. A method for rapid prediction of the eddy current testing signals arisen from these idealized cracks is given then by extending a knowledge based fast forward solver developed by authors to the case of a non-vanishing conductivity. On the other hand, the inverse algorithm of conjugate gradient method is improved to reconstruct the crack parameters and is implemented with the pick-up signals and gradients calculated by using the rapid forward solver. Several examples are presented finally for validating the proposed strategy. The results verified that both of the models can give reasonable reconstruction results in case of a low noise level. The model concerning the touch of crack surfaces with a conducting band region surrounded by the crack edge, however, is proved more efficient than the model using a conductivity distribution from the point of view of both reconstruction speed and accuracy.

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