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JAEA Reports

Validation of repairing method for concrete wall of the JMTR tank-yard building

Sugaya, Naoto; Okada, Yuji; Nishimura, Arashi; Sonobe, Hiroshi; Kimura, Nobuaki; Kimura, Akihiro; Hanawa, Yoshio; Nemoto, Hiroyoshi

JAEA-Testing 2020-004, 67 Pages, 2020/08

JAEA-Testing-2020-004.pdf:8.17MB

In the Japan Materials Testing Reactor (JMTR), the leakage accidents of radioactive waste liquid were occurred from the tanks and pipes of the liquid waste disposal facility in the JMTR tank-yard building in JFY2014. In order to respond to the accident, the tanks and pipes were replaced from JFY2016 to 2019. On the other hand, a lot of cracks were occurred on the concreate wall of the tank-yard building when the frame structure supports were fixed to the concrete wall in the replacement work. Thus, it is necessary to repair the concreate wall of the tank-yard building. Especially, some cracks with swelling (cone-shaped fracture) were raised around some anchor bolts (the post-installed chemical anchor bolts) fixed the frame structure supports. The repairing method for the cone-shaped fracture of the concrete wall is standardized, but there was no reference value of tensile strength for the validation of the post-installed chemical anchor bolts after the repairing method. In this report, the repairing method was selected for the cone-shaped fracture on the concreate wall and the reference value of tensile strength for the validation of the post-installed chemical anchor bolts by this repairing method. The mock-ups for repairing cone-shaped fracture were fabricated by the selected repairing method and the tensile tests of the post-installed chemical anchor bolts were performed. From the results, the validation of the repairing method was obtained in this test and it was obvious the repairing of cone-shaped fracture is preferable method for the concreate wall of the JMTR tank-yard building.

Journal Articles

Improvement of plant reliability based on combining of prediction and inspection of crack growth due to intergranular stress corrosion cracking

Uchida, Shunsuke; Chimi, Yasuhiro; Kasahara, Shigeki; Hanawa, Satoshi; Okada, Hidetoshi*; Naito, Masanori*; Kojima, Masayoshi*; Kikura, Hiroshige*; Lister, D. H.*

Nuclear Engineering and Design, 341, p.112 - 123, 2019/01

 Times Cited Count:1 Percentile:50.57(Nuclear Science & Technology)

Improvement of plant reliability based on reliability-centered-maintenance (RCM) is going to be undertaken in NPPs. RCM is supported by risk-based maintenance (RBM). The combination of prediction and inspection is one of the key issues to promote RBM. Early prediction of IGSCC occurrence and its propagation should be confirmed throughout the entire plant systems which should be accomplished by inspections at the target locations followed by timely application of suitable countermeasures. From the inspections, accumulated data will be applied to confirm the accuracy of the code, to tune some uncertainties of the key data for prediction, and then, to increase their accuracy. The synergetic effects of prediction and inspection on application of effective and suitable countermeasures are expected. In the paper, the procedures for the combination of prediction and inspection are introduced.

JAEA Reports

XAFS measurement of simulated waste glass samples (Borosilicate glass including vanadium)

Nagai, Takayuki; Kobayashi, Hidekazu; Sasage, Kenichi; Ayame, Yasuo; Okamoto, Yoshihiro; Shiwaku, Hideaki; Matsuura, Haruaki*; Uchiyama, Takafumi*; Okada, Yukiko*; Nezu, Atsushi*; et al.

JAEA-Research 2016-015, 52 Pages, 2016/11

JAEA-Research-2016-015.pdf:37.48MB

The local structure of waste elements in simulated waste glasses including V was estimated by using synchrotron XAFS measurement in this study. The results are as follows. (1) V has a high possibility which exists in the glass phase in the case of frit, and V can regard both samples as stable 4 coordination structure. (2) Zn, Ce, Nd, Zr, and Mo exist in the glass phase, and the difference is admitted by the percentage of Ce(III) and Ce(IV) by the composition. (3) Ru is separated from the glass phase as RuO$$_{2}$$ crystalline, both of metal and oxide exist in Rh, and Pd is separated out as metal. (4) It was confirmed that the regularity of the local structure of Zr and Mo in the molten glasses retreats as a result of the XAFS measurement at high temperature. (5) The XAFS measurement of molten glasses were performed at 1200$$^{circ}$$C, so it would be possible to acquire excellent data by improving the shapes of the sample cell.

Journal Articles

Computations of stress intensity factors for semi-elliptical cracks with high aspect ratios by using the tetrahedral finite element; Fully automated parametric study

Okada, Hiroshi*; Koya, Hirohito*; Kawai, Hiroshi*; Li, Y.; Osakabe, Kazuya*

Engineering Fracture Mechanics, 158, p.144 - 166, 2016/06

 Times Cited Count:9 Percentile:46.17(Mechanics)

The stress intensity factor (SIF) solutions of semi-elliptical cracks with high aspect ratios in plate and thick wall cylinder have been investigated under various assumed stress distributions. The authors have developed an automated analysis procedure to perform parametric studies on crack shapes and loading conditions. It consists of programs to perform automatic mesh generation, analysis execution including assignments of boundary conditions and SIF evaluations by virtual crack closure integral method. It was also found that SIF solutions for the thick wall cylinder and for the complex structure could be estimated by those for the flat plate.

Journal Articles

Development of stress intensity factors for surface cracks with large aspect ratio in plates

Li, Y.; Hasegawa, Kunio; Katsumata, Genshichiro; Osakabe, Kazuya*; Okada, Hiroshi*

Journal of Pressure Vessel Technology, 137(5), p.051207_1 - 051207_8, 2015/10

 Times Cited Count:3 Percentile:74.2(Engineering, Mechanical)

A number of surface cracks with large aspect ratio have been detected in components of nuclear power plants in recent years. The depths of these cracks are even larger than the half of crack lengths. However, the solutions of the stress intensity factor were not provided for semi-elliptical surface cracks with large aspect ratio in the current fitness-for-service codes. In this study, in order to conduct integrity assessment for cracked components, the solutions of the stress intensity factor were calculated using finite element analysis for semi-elliptical surface cracks with large aspect ratio in plates. Solutions were provided at both the deepest and the surface points of the surface cracks. Some of solutions were compared with the available existing results. As the result, it was concluded that the solutions proposed in this paper are applicable in engineering applications.

JAEA Reports

Performance confirmation operation of water environment control facility

Magome, Hirokatsu; Okada, Yuji; Tomita, Kenji; Iida, Kazuhiro; Ando, Hitoshi; Yonekawa, Akihisa; Ueda, Haruyasu; Hanawa, Hiroshi; Kanno, Masaru; Sakuta, Yoshiyuki

JAEA-Technology 2015-025, 100 Pages, 2015/09

JAEA-Technology-2015-025.pdf:78.32MB

In Japan Atomic Energy Agency, in order to solve the problem in the long-term operation of a light water reactor, preparation which does the irradiation experiment of light-water reactor fuel and material was advanced. JMTR stopped after the 165th operation cycle in August 2006, and is advancing renewal of the irradiation facility towards re-operation. The material irradiation test facility was installed from 2008 fiscal year to 2012 fiscal year in JMTR. The material irradiation test facility is used for IASCC study, and that consists of mainly three equipments. This report is described performance operating test of the water environmental control facilities for IASCC study carried out 2013 fiscal year.

Journal Articles

Model magnet development of D1 beam separation dipole for the HL-LHC upgrade

Nakamoto, Tatsushi*; Sugano, Michinaka*; Xu, Q.*; Kawamata, Hiroshi*; Enomoto, Shun*; Higashi, Norio*; Idesaki, Akira; Iio, Masami*; Ikemoto, Yukio*; Iwasaki, Ruri*; et al.

IEEE Transactions on Applied Superconductivity, 25(3), p.4000505_1 - 4000505_5, 2015/06

Recently, development of superconducting magnet system with high radiation resistance has been demanded for application in accelerator facilities such as CERN LHC. In order to realize superconducting magnet system with high radiation resistance, it is necessary to develop electrical insulator with high radiation resistance because the electrical insulator is made of organic materials whose radiation resistance is inferior to that of inorganic materials. We developed a glass fiber reinforced plastic with bismaleimide-triazine resin. The developed material showed excellent radiation resistance; the material evolved gases of 5$$times$$10 $$^{-5}$$mol/g and maintained flexural strength of 640MPa (90% of initial value).

Journal Articles

High proton radiation tolerance of InAsSb quantum-well-based micro-Hall sensors

Abderrahmane, A.*; Ko, P. J.*; Okada, Hiroshi*; Sato, Shinichiro; Oshima, Takeshi; Shibasaki, Ichiro*; Sandhu, A.*

IEEE Electron Device Letters, 35(12), p.1305 - 1307, 2014/12

 Times Cited Count:0 Percentile:100(Engineering, Electrical & Electronic)

Tolerance of AlInSb/InAsSb/AlInSb heterostructures quantum-well-based micro-Hall sensors against proton irradiation of 380 keV and proton fluence in the range 10$$^{11}$$ and 10$$^{16}$$ (proton/cm$$^2$$) is reported. Defects and deep levels induced by proton irradiation into the heterostructures caused decreases in the mobility of the micro-Hall sensors. Degradation of the magnetic sensitivity started at a proton fluence of 10$$^{13}$$ (proton/cm$$^2$$) and continued with increasing proton fluence. The variation of the micro-Hall sensors sensitivity was minimal in low doped AlInSb/InAsSb/AlInSb heterostructure quantum wells. These micro-Hall sensors were operable even at proton fluence of 10$$^{16}$$ (proton/cm$$^{2}$$), which makes these devices suitable for space applications with lifetime of thousands of years in the outer space.

Journal Articles

Proton irradiation enhancement of low-field negative magnetoresistance sensitivity of AlGaN/GaN-based magnetic sensor at cryogenic temperature

Abderrahmane, A.*; Ko, P. J.*; Okada, Hiroshi*; Sato, Shinichiro; Oshima, Takeshi; Sandhu, A.*

IEEE Electron Device Letters, 35(11), p.1130 - 1132, 2014/11

 Times Cited Count:5 Percentile:60.86(Engineering, Electrical & Electronic)

The longitudinal and transverse magnetoresistances of AlGaN/GaN heterostructure-based micro-Hall sensors were compared with samples irradiated with protons with an energy of 380 keV and fluence of 10$$^{14}$$ (protons/cm$$^{2}$$). Increases in the elastic and inelastic scattering were deduced from weak localization behavior in both samples. The AlGaN/GaN micro-Hall sensors showed stable magnetic sensitivity in non and irradiated samples and increased resistivity after proton irradiation yielded an enhanced magnetoresistance sensitivity in nonirradiated sensors from 160 to 417 V/(A $$cdot$$ T). The minimum detectable magnetic field of irradiated micro-Hall sensors determined from magneto-voltage measurements at 4 K was similar to the minimum detectable magnetic field in the nonirradiated sensors.

JAEA Reports

Installation of the water environment irradiation facility for the IASCC research under the BWR/PWR irradiation environment, 2

Magome, Hirokatsu; Okada, Yuji; Hanawa, Hiroshi; Sakuta, Yoshiyuki; Kanno, Masaru; Iida, Kazuhiro; Ando, Hitoshi; Yonekawa, Akihisa; Ueda, Haruyasu; Shibata, Mitsunobu

JAEA-Technology 2014-023, 267 Pages, 2014/07

JAEA-Technology-2014-023-01.pdf:103.68MB
JAEA-Technology-2014-023-02.pdf:71.92MB

In Japan Atomic Energy Agency, in order to solve the problem in the long-term operation of a light water reactor, preparation which does the irradiation experiment of light-water reactor fuel and material was advanced. JMTR stopped after the 165th operation cycle in August 2006, and is advancing renewal of the irradiation facility towards re-operation. The material irradiation test facility was installed from 2008 fiscal year to 2012 fiscal year in JMTR. This report summarizes manufacture and installation of the material irradiation test facility for IASCC research carried out from 2012 to 2014 in the follow-up report reported before (JAEA-Technology 2013-019).

Journal Articles

HCM12A Cr-rich oxide layer investigation using 3D atom probe

Kikuchi, Kenji*; Okada, Noriyuki*; Kato, Mikio*; Uchida, Hiroshi*; Saito, Shigeru

Journal of Nuclear Materials, 450(1-3), p.237 - 243, 2014/07

 Times Cited Count:3 Percentile:67.39(Materials Science, Multidisciplinary)

Three-dimensional atom probe techniques were applied to the investigation on the oxide scale in 12Cr ferritic-martensitic steel, HCM12A. A duplex oxide scale was formed in lead bismuth eutectic at 450-500$$^{circ}$$C, during 5500 h. Samples were located 500-700 nm away from the boundary between magnetite and Fe-Cr spinel layers, while the total oxide layer thickness is 18 $$mu$$m. It detected super enrichment of Cr with a size of ten nm roughly, as well as depletion of Fe and enrichment of O at the same site. Surrounding the Cr super enrichment area, enrichment of Si was newly noticed due to the scanned profile of detected atom counts. It is also confirmed that Pb and Bi concentration in the observed spinel region is almost null or less than 0.01 atomic percent, which is possible detecting lowest limit.

Journal Articles

Development of the irradiation facility for simulating condition of light-water reactor

Kitagishi, Shigeru; Endo, Yasuichi; Okada, Yuji; Hanawa, Hiroshi; Matsui, Yoshinori

UTNL-R-0486, p.7_1 - 7_10, 2014/03

no abstracts in English

Journal Articles

Effect of annealing on proton irradiated AlGaN/GaN based micro-Hall sensors

Abderrahmane, A.*; Takahashi, Hiroki*; Tashiro, Tatsuya*; Ko, P. J.*; Okada, Hiroshi*; Sato, Shinichiro; Oshima, Takeshi; Sandhu, A.*

AIP Conference Proceedings 1585, p.123 - 127, 2014/02

 Times Cited Count:1 Percentile:41.7

The effect of annealing at 673 K on irradiated micro-Hall sensors irradiated with protons at 380 keV and fluences of 1$$times 10^{14}$$ cm$$^{-2}$$, 1$$times 10^{15}$$ cm$$^{-2}$$, 1$$times 10^{16}$$ cm$$^{-2}$$ is reported. Cathodoluminescence measurements were carried out at room temperature before and after annealing and showed improvement in the band edge band emission of the GaN layer. After annealing a sensor irradiated by 1$$times 10^{15}$$ cm$$^{-2}$$ the device became operational with improvements in its magnetic sensitivity. All irradiated sensors showed improvement in their electrical characteristics after annealing.

Journal Articles

Partial recovery of the magnetoelectrical properties of AlGaN/GaN-based micro-Hall sensors irradiated with protons

Abderrahmane, A.*; Tashiro, Tatsuya*; Takahashi, Hiroki*; Ko, P. J.*; Okada, Hiroshi*; Sato, Shinichiro; Oshima, Takeshi; Sandhu, A.*

Applied Physics Letters, 104(2), p.023508_1 - 023508_4, 2014/01

 Times Cited Count:4 Percentile:81.65(Physics, Applied)

The effect of annealing on the magnetoelectrical properties of proton-irradiated micro-Hall sensors at an energy of 380 keV and very high proton fluences was studied. Recovery of the electron mobility and a decrease in the sheet resistance of the annealed micro-Hall sensors, as well as an enhancement in their magnetic sensitivity were reported. Trap removal and an improvement in the crystal quality by removing defects were confirmed through current-voltage measurements and Raman spectroscopy, respectively.

JAEA Reports

Installation of the water environment irradiation facility for the IASCC research under the BWR irradiation environment, 1

Okada, Yuji; Magome, Hirokatsu; Hanawa, Hiroshi; Omi, Masao; Kanno, Masaru; Iida, Kazuhiro; Ando, Hitoshi; Shibata, Mitsunobu; Yonekawa, Akihisa; Ueda, Haruyasu

JAEA-Technology 2013-019, 236 Pages, 2013/10

JAEA-Technology-2013-019.pdf:45.07MB

In Japan Atomic Energy Agency, in order to solve the problem in the long-term operation of a light water reactor, preparation which does the irradiation experiment of light-water reactor fuel and material is advanced. JMTR stopped after the 165th operation cycle in August 2006, and is advancing renewal of the irradiation facility towards re-operation. This material irradiation test facility and power ramping test facility for doing the neutron irradiation test of the fuel and material for light water reactors is scheduled to be manufactured and installed between the 2008 fiscal year and the 2012 fiscal year. This report summarizes manufacture and installation of the material irradiation test facility for IASCC research carried out from the 2008 fiscal year to the 2010 fiscal year.

Journal Articles

Effect of proton irradiation on AlGaN/GaN micro-Hall sensors

Abderrahmane, A.*; Koide, Shota*; Okada, Hiroshi*; Takahashi, Hiroki*; Sato, Shinichiro; Oshima, Takeshi; Sandhu, A.*

Applied Physics Letters, 102(19), p.193510_1 - 193510_4, 2013/05

 Times Cited Count:6 Percentile:66.4(Physics, Applied)

The magnetoelectric properties of AlGaN/GaN micro-Hall effect sensors were studied after 380 keV proton irradiation. After irradiation the current-voltage measurements, stability of the magnetic sensitivity of the sensors, and the sheet electron density were degraded with a dramatic decrease of the electron mobility at high temperatures. Raman spectroscopy showed a degradation in the crystalline quality of GaN crystal, but there was no change in the strain.

Journal Articles

Effect of Proton Irradiation on 2DEG in AlGaN/GaN Heterostructures

Abderrahmane, A.*; Koide, Shota*; Tahara, Tomoyuki*; Sato, Shinichiro; Oshima, Takeshi; Okada, Hiroshi*; Sandhu, A.*

Journal of Physics; Conference Series, 433, p.012011_1 - 012011_8, 2013/04

 Times Cited Count:4 Percentile:18.2

We investigated the effect of high energy and high fluence proton irradiation on magnetoelectric properties of AlGaN/GaN micro-Hall sensors from 5.4 K to room temperature. The sensors show good resistance versus the irradiation translated by the stability of the sheet density therefore the stability of the absolute sensitivity of the sensor. However, the proton irradiation damaged the electrical properties of the sensor indicated by the dramatically decrease of the mobility at low temperature by rate of about 81% at 5.4 K. The existing of the 2DEG system either after irradiation with high energy was confirmed by investigation the magnetotransport measurements at low temperature and which show Shubnikov de Haas oscillations at high magnetic field. Damping of the Shubnikov de Haas oscillations and disappearance of Landau plateaus after irradiation were related to the degradation in the mobility causing by increasing the scattering at the interface.

Journal Articles

Development of new irradiation facility for BWR safety research

Okada, Yuji; Magome, Hirokatsu; Iida, Kazuhiro; Hanawa, Hiroshi; Omi, Masao

UTNL-R-0483, p.10_4_1 - 10_4_10, 2013/03

In JAEA(Japan Atomic Energy Agency), about the irradiation embrittlement of the reactor pressure vessel and the stress corrosion cracking of reactor core composition apparatus concerning the long-term use of the light water reactor (BWR), in order to check the influence of the temperature, pressure, and water quality, etc on BWR condition. The water environmental control facility which performs irradiation assisted stress corrosion-cracking (IASCC) evaluation under BWR irradiation environment was fabricated in JMTR. (Japan Materials Testing Reactor). This report is described the outline of manufacture of the water environmental control facility for doing an irradiation test using the saturation temperature capsule after JMTR re-operation.

Journal Articles

Robust Hall effect magnetic field sensors for operation at high temperatures and in harsh radiation environments

Abderrahmane, A.*; Koide, Shota*; Sato, Shinichiro; Oshima, Takeshi; Sandhu, A.*; Okada, Hiroshi*

IEEE Transactions on Magnetics, 48(11), p.4421 - 4423, 2012/11

 Times Cited Count:14 Percentile:34.53(Engineering, Electrical & Electronic)

Recent industrial trends indicate increasing demand for Hall effect sensors for monitoring magnetic fields under extreme conditions such as high temperatures and under harmful radiation conditions. In this study, robust and high sensitivity Hall effect sensors using AlGaN/GaN heterostructures with a two-dimensional electron gas at the heterointerface were fabricated, and their magnetic properties were investigated. The AlGaN/GaN 2DEG Hall sensors were stable to at least 400 $$^{circ}$$C and even after irradiation of 380 keV protons at the fluence of 1 $$times$$ 10$$^{14}$$ /cm$$^2$$. The results showed that the AlGaN/GaN 2DEG Hall sensors had superior radiation tolerance to AlGaAs/GaAs and AlInSb/InAsSb/AlInSb magnetic sensors.

Journal Articles

Effects of proton irradiation on the magnetoelectric properties of 2DEG AlGaN/GaN micro-hall sensors

Okada, Hiroshi*; Abderrahmane, A.*; Koide, Shota*; Takahashi, Hiroki*; Sato, Shinichiro; Oshima, Takeshi; Sandhu, A.*

Journal of Physics; Conference Series, 352, p.012010_1 - 012010_5, 2012/03

 Times Cited Count:5 Percentile:11.16

93 (Records 1-20 displayed on this page)