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Journal Articles

Verification of a probabilistic fracture mechanics code PASCAL4 for reactor pressure vessels

Lu, K.; Katsuyama, Jinya; Li, Y.; Miyamoto, Yuhei*; Hirota, Takatoshi*; Itabashi, Yu*; Nagai, Masaki*; Suzuki, Masahide*; Kanto, Yasuhiro*

Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 9 Pages, 2019/05

Journal Articles

Analytical studies of three-dimensional evaluation of radionuclide distribution in zeolite wastes through gamma scanning of adsorption vessels

Matsumura, Taichi; Nagaishi, Ryuji; Katakura, Junichi*; Suzuki, Masahide*

Nuclear Science and Engineering, 192(1), p.70 - 79, 2018/10

 Percentile:100(Nuclear Science & Technology)

The gamma-scanning of SDS (submerged demineralizer system) vessel used as a typical vessel for decontamination of radioactive water at Three Mile Island Unit 2 (TMI-2) accident was simulated in the axial and radial directions of real and cylindrical-shaped vessels by using a Monte Carlo calculation code (PHITS) on the basis of the geometrical and compositional information of vessel and gamma-scanning available in the previous reports at the accident. In the axial simulation, the true distribution of radioactive $$^{137}$$Cs in the zeolite packed bed of vessel was successfully evaluated when a correction function derived from a virtual constant distribution of $$^{137}$$Cs was applied to the reported gamma-scanning profile. In the radial simulation, the virtual disk-formed and shell-formed sources of $$^{137}$$Cs displaced in the packed bed were clearly observed from the top and bottom views of vessel. This new radial gamma-scanning indicates that the radial localization of $$^{137}$$Cs could be well observed by measuring gamma-ray from the top view of vessel during storage. We further examined the radial gamma-scanning from the side view whether the radial localization of $$^{137}$$Cs can be confirmed in the normally existing gamma-scanning room or not.

Journal Articles

Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex, 2; Neutron scattering instruments

Nakajima, Kenji; Kawakita, Yukinobu; Ito, Shinichi*; Abe, Jun*; Aizawa, Kazuya; Aoki, Hiroyuki; Endo, Hitoshi*; Fujita, Masaki*; Funakoshi, Kenichi*; Gong, W.*; et al.

Quantum Beam Science (Internet), 1(3), p.9_1 - 9_59, 2017/12

The neutron instruments suite, installed at the spallation neutron source of the Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC), is reviewed. MLF has 23 neutron beam ports and 21 instruments are in operation for user programs or are under commissioning. A unique and challenging instrumental suite in MLF has been realized via combination of a high-performance neutron source, optimized for neutron scattering, and unique instruments using cutting-edge technologies. All instruments are/will serve in world-leading investigations in a broad range of fields, from fundamental physics to industrial applications. In this review, overviews, characteristic features, and typical applications of the individual instruments are mentioned.

Journal Articles

Verification of probabilistic fracture mechanics analysis code PASCAL

Li, Y.; Katsumata, Genshichiro*; Masaki, Koichi*; Hayashi, Shotaro*; Itabashi, Yu*; Nagai, Masaki*; Suzuki, Masahide*; Kanto, Yasuhiro*

Proceedings of 25th International Conference on Nuclear Engineering (ICONE-25) (CD-ROM), 10 Pages, 2017/07

In Japan, a PFM analysis code PASCAL (PFM Analysis of Structural Components in Aging LWR) has been developed by the Japan Atomic Energy Agency to evaluate the through-wall cracking frequencies of Japanese reactor pressure vessels (RPVs) considering neutron irradiation embrittlement and pressurized thermal shock transients. In this study, as a part of the verification activities, a working group was established in Japan, with seven organizations from industry, universities and institutes voluntarily participating as members. The source program of PASCAL was released to the members of the working group. Through one year activities, the applicability of PASCAL for structural integrity assessments of domestic RPVs was confirmed with great confidence. This paper presents the details of the verification activities of the working group including the verification plan, approaches and results.

JAEA Reports

Activities of working group on verification of PASCAL; Fiscal year 2015

Li, Y.; Hayashi, Shotaro*; Itabashi, Yu*; Nagai, Masaki*; Kanto, Yasuhiro*; Suzuki, Masahide*; Masaki, Koichi*

JAEA-Review 2017-005, 80 Pages, 2017/03


For the improvement of the structural integrity assessment methodology on reactor pressure vessels (RPVs), the probabilistic fracture mechanics (PFM) analysis code PASCAL has been developed and improved in JAEA based on latest knowledge. The PASCAL code evaluates the failure probabilities and frequencies of Japanese RPVs under transient events such as pressurized thermal shock considering neutron irradiation embrittlement. In order to confirm the reliability of the PASCAL as a domestic standard code and to promote the application of PFM on the domestic structural integrity assessments of RPVs, it is important to verify the probabilistic variables, functions and models incorporated in the PASCAL and summarize the verification processes and results as a document. On the basis of these backgrounds, we established a working group, composed of experts on this field besides the developers, on the verification of the PASCAL3 which is a PFM analysis module of PASCAL, and the source program of PASCAL3 was released to the members of working group. Through one year activities, the applicability of PASCAL in structural integrity assessments of domestic RPVs was confirmed with great confidence. This report summarizes the activities of the working group on the verification of PASCAL in FY2015.

Journal Articles

Development of inspection and repair techniques for reactor vessel of experimental fast reactor "Joyo"; Replacement of upper core structure

Takamatsu, Misao; Kawahara, Hirotaka; Ito, Hiromichi; Ushiki, Hiroshi; Suzuki, Nobuhiro; Sasaki, Jun; Ota, Katsu; Okuda, Eiji; Kobayashi, Tetsuhiko; Nagai, Akinori; et al.

Nippon Genshiryoku Gakkai Wabun Rombunshi, 15(1), p.32 - 42, 2016/03

In the experimental fast reactor Joyo, it was confirmed that the top of the irradiation test sub-assembly of "MARICO-2" (material testing rig with temperature control) had been broken and bent onto the in-vessel storage rack as an obstacle and had damaged the upper core structure (UCS). This paper describes the results of the in-vessel repair techniques for UCS replacement, which are developed in Joyo. UCS replacement was successfully completed in 2014. In-vessel repair techniques for sodium cooled fast reactors (SFRs) are important in confirming its safety and integrity. In order to secure the reliability of these techniques, it was necessary to demonstrate the performance under the actual reactor environment with high temperature, high radiation dose and remained sodium. The experience and knowledge gained in UCS replacement provides valuable insights into further improvements for In-vessel repair techniques in SFRs.

Journal Articles

Development status of the NMR system for the polarized $$^{3}$$He Neutron Spin Filter (NSF) in the MLF at J-PARC

Sakai, Kenji; Oku, Takayuki; Hayashida, Hirotoshi*; Kira, Hiroshi*; Hiroi, Kosuke; Ino, Takashi*; Oyama, Kenji*; Okawara, Manabu*; Kakurai, Kazuhisa; Shinohara, Takenao; et al.

JPS Conference Proceedings (Internet), 8, p.036015_1 - 036015_6, 2015/09

The polarized $$^{3}$$He filter, which polarizes neutrons due to a large neutron absorption cross section of $$^{3}$$He with strong spin selectivity, becomes a convenient neutron spin filter (NSF) because it is operated immediately after its installation in beam lines without any neutron beam adjustments. For realizing such the NSF, a nuclear magnetic resonance (NMR) system is indispensable for monitoring $$^{3}$$He nuclear spin polarization ${it P}$ of the NSF. We have developed the flexible NMR system based on adiabatic fast passage (AFP) and pulse NMR methods by using their complementary features. In comparing with the values of ${it P}$ obtained by neutron transmission measurement at the beam line 10 of the J-PARC, we measured the correlations between the AFP and pulse NMR signals as changing condition of temperature, amplitude and applying period of the radio frequency field for the pulse NMR, and so on. As the results, we confirmed that our system would function enough as the ${it P}$ monitor.

Journal Articles

On-site background measurements for the J-PARC E56 experiment; A Search for the sterile neutrino at J-PARC MLF

Ajimura, Shuhei*; Bezerra, T. J. C.*; Chauveau, E.*; Enomoto, T.*; Furuta, Hisataka*; Harada, Masahide; Hasegawa, Shoichi; Hiraiwa, T.*; Igarashi, Yoichi*; Iwai, Eito*; et al.

Progress of Theoretical and Experimental Physics (Internet), 2015(6), p.063C01_1 - 063C01_19, 2015/06

 Times Cited Count:1 Percentile:81.9(Physics, Multidisciplinary)

The J-PARC E56 experiment aims to search for sterile neutrinos at the J-PARC Materials and Life Science Experimental Facility (MLF). In order to examine the feasibility of the experiment, we measured the background rates of different detector candidate sites, which are located at the third floor of the MLF, using a detector consisting of plastic scintillators with a fiducial mass of 500 kg. The gammas and neutrons induced by the beam as well as the backgrounds from the cosmic rays were measured, and the results are described in this article.

Journal Articles

Effects of irradiation induced Cu clustering on vickers hardness and electrical resistivity of Fe-Cu model alloys

Tobita, Toru; Nakagawa, Sho*; Takeuchi, Tomoaki; Suzuki, Masahide; Ishikawa, Norito; Chimi, Yasuhiro; Saito, Yuichi; Soneda, Naoki*; Nishida, Kenji*; Ishino, Shiori*; et al.

Journal of Nuclear Materials, 452(1-3), p.241 - 247, 2014/09

 Times Cited Count:8 Percentile:25.95(Materials Science, Multidisciplinary)

Three kinds of Fe-based model alloys, Fe-0.018 atomic percent (at.%) Cu, Fe-0.53at.%Cu, and Fe-1.06at.%Cu were irradiated with 2 MeV electrons up to the dose of 2$$times$$10$$^{-5}$$ dpa at 250$$^{circ}$$C. After the irradiation, the increase in Vickers hardness and the decrease in electrical resistivity were observed. The increase in hardness by electron irradiation is proportional to the product of the Cu contents and the square root of the electron dose. The decrease in electrical resistivity is proportional to the product of the square of Cu contents and the electron dose. Cu clustering in the materials with electron irradiation and thermal aging was observed by means of the three dimensional atom probes (3D-AP). The change in Vickers hardness and electrical resistivity is well correlated with the volume fraction of Cu clusters.

Journal Articles

Effects of thermal aging on microstructure and hardness of stainless steel weld-overlay claddings of nuclear reactor pressure vessels

Takeuchi, Tomoaki; Kakubo, Yuta*; Matsukawa, Yoshitaka*; Nozawa, Yasuko*; Toyama, Takeshi*; Nagai, Yasuyoshi*; Nishiyama, Yutaka; Katsuyama, Jinya; Yamaguchi, Yoshihito; Onizawa, Kunio; et al.

Journal of Nuclear Materials, 452(1-3), p.235 - 240, 2014/09

 Times Cited Count:19 Percentile:5.58(Materials Science, Multidisciplinary)

Microstructures and hardness of stainless steel weld overlay cladding of reactor pressure vessels subjected to the thermal aging at 400 $$^{circ}$$C for 100-10,000 h were investigated using atom probe tomography and nanoindentation technique. The Cr concentration fluctuation in the $$delta$$-ferrite phase caused by spinodal decomposition rapidly progressed by the 100 h aging while NiSiMn clusters increased in number density at 2,000 h and coarsened at 10,000 h. The hardness of the $$delta$$-ferrite phase also rapidly increased at the short aging time. The Cr concentration fluctuation and the hardness were in good correlation with the degree of the Cr concentration fluctuation rather than the formation of the NiSiMn clusters. These results strongly suggested that the dominant factor of the hardening of the $$delta$$-ferrite phase by the thermal aging was Cr spinodal decomposition.

Journal Articles

Development of portable polarized $$^{3}$$He neutron spin filter and its application to magnetic field imaging at J-PARC

Sakai, Kenji; Oku, Takayuki; Hayashida, Hirotoshi; Kira, Hiroshi*; Shinohara, Takenao; Oikawa, Kenichi; Harada, Masahide; Kakurai, Kazuhisa; Aizawa, Kazuya; Arai, Masatoshi; et al.

Journal of Physics; Conference Series, 528, p.012016_1 - 012016_7, 2014/07


In polarized neutron experiments, it is interested in expanding measurable neutron energy region up to epithermal neutrons. For realizing this situation, a Polarized $$^{3}$$He Spin Flipper (PHSF) has a key role because it can polarize from cold to epithermal neutrons, and flip neutron spins by flipping the $$^{3}$$He nuclear spin direction. We have developed the portable PHSF consisting of a cylindrical glass cell filled with $$^{3}$$He gas which is installed a solenoid coil of 20 cm in diameter and 30 cm long. After polarizing the $$^{3}$$He gas by irradiating a laser light based on a SEOP technique, the PHSF is brought by hands to experimental areas with kept its polarization. We carried out the feasibility test on our portable PHSF in the MLF of J-PARC and demonstrated it worked well by evaluating flipping ratios of polarized neutrons and attempting to visualize magnetic fields generated by sample coils.

Journal Articles

Feasibility demonstration of a new Fermi chopper with supermirror-coated slit package

Nakamura, Mitsutaka; Kambara, Wataru; Krist, T.*; Shinohara, Takenao; Ikeuchi, Kazuhiko*; Arai, Masatoshi; Kajimoto, Ryoichi; Nakajima, Kenji; Tanaka, Hiromichi; Suzuki, Junichi*; et al.

Nuclear Instruments and Methods in Physics Research A, 737, p.142 - 147, 2014/02

 Times Cited Count:2 Percentile:72.96(Instruments & Instrumentation)

The efficiency of inelastic neutron scattering measurements using a chopper spectrometer can be markedly improved by utilizing multiple incident energies (Multi-Ei method). However, in conventional chopper systems, optimization of the experimental condition for all incident energies is absolutely impossible. We developed a new Fermi chopper with a supermirror-coated slit package in order to overcome the problem and experimentally demonstrated that the full optimization of the experimental condition for multiple incident energies is nearly achieved.

Journal Articles

Effect of neutron irradiation on the microstructure of the stainless steel electroslag weld overlay cladding of nuclear reactor pressure vessels

Takeuchi, Tomoaki; Kakubo, Yuta*; Matsukawa, Yoshitaka*; Nozawa, Yasuko*; Nagai, Yasuyoshi*; Nishiyama, Yutaka; Katsuyama, Jinya; Onizawa, Kunio; Suzuki, Masahide

Journal of Nuclear Materials, 443(1-3), p.266 - 273, 2013/11

 Times Cited Count:8 Percentile:29.95(Materials Science, Multidisciplinary)

Investigation on irradiation effects of weld-overlay claddings is necessary for safety assessment of reactor pressure vessels. We investigated microstructural changes in the cladding, which was composed of about 90% austenite and 10% $$delta$$-ferrite phases, subjected to the neutron irradiation to 7.2$$times$$10$$^{19}$$ n/cm$$^{2}$$ at 290$$^{circ}$$C, by 3D atom probe tomography technique. In the ferrite phase, the amplitude of the Cr and Si concentration fluctuation was increased by the irradiation and Ni and Mn concentration fluctuations were newly occurred. In the austenite phase, $$gamma$$'(Ni$$_{3}$$Si) -like clusters were formed. In contrast, the results of our previous work on the cladding subjected to thermal aging showed the amplitude of the Cr fluctuation was significantly increased and G (Ni-Si-Mn) phase was formed in the ferrite phase. Moreover, no changes were observed in the austenite by the aging.

JAEA Reports

Study of cable ageing mechanism for nuclear power plant (Contract research)

Seguchi, Tadao*; Tamura, Kiyotoshi*; Watashi, Katsumi; Suzuki, Masahide; Shimada, Akihiko; Sugimoto, Masaki; Idesaki, Akira; Yoshikawa, Masahito; Oshima, Takeshi; Kudo, Hisaaki*

JAEA-Research 2012-029, 158 Pages, 2012/12


The degradation mechanisms of ethylene-propylene rubber (EPR), crosslinked polyethylene (XLPE), polyvinylchloride (PVC), and silicone rubber (SiR) as the cable insulation materials were investigated for the cable ageing research of the nuclear power plant. The materials as same insulations for the practical cable (practical formulation) and as the model formulation containing specific additive were selected. They were exposed to the accelerated radiation and thermal environments. The mechanical properties, the crosslinking and chain scission, and the distribution of antioxidant and of oxidative products were measured and analyzed.

JAEA Reports

Proceedings of 2012 JAEA/KAERI Joint Seminar on Advanced Irradiation and PIE Technologies; March 28-30, 2012, Mito, Japan

Ishihara, Masahiro; Ishitsuka, Etsuo; Suzuki, Masahide

JAEA-Conf 2012-002, 179 Pages, 2012/12


Under the "Arrangement for Corporation in the field of peaceful uses of Nuclear Energy between the Japan Atomic Energy Agency (JAEA) and the Korean Atomic Energy Research Institute (KAERI)", the 2012 JAEA/KAERI Joint Seminar on Advanced Irradiation and PIE (post-irradiation examination) Technologies has been held at Mito, Japan from March 28 to 30, 2012. This triennial seminar is the seventh in series of bilateral exchange of irradiation and PIE technologies and research reactor management. Since the first joint seminar on the PIE Technology between JAERI (Japan Atomic Energy Research Institute, former agency of JAEA) and KAERI was held at JAERI Oarai Research Institute, Japan in 1992, the international cooperation program between JAEA and KAERI has been actively carried out in the field of neutron irradiation. At the fifth seminar in 2005 and sixth in 2008, the irradiation technology and the research reactor management fields were included, respectively, to the joint seminar, and it covers whole areas of irradiation using research reactors. In this seminar total 37 presentations were made in three technical sessions, which are "research reactor management", "advanced irradiation technology" and "post-irradiation examination technology", and active information exchange was done among participants. Papers or manuscripts presented in the 2012 JAEA/KAERI Joint Seminar on Advanced Irradiation and PIE Technologies are contained in the proceedings.

Journal Articles

Current status of JMTR

Ishihara, Masahiro; Kimura, Nobuaki; Takemoto, Noriyuki; Ooka, Makoto; Kaminaga, Masanori; Kusunoki, Tsuyoshi; Komori, Yoshihiro; Suzuki, Masahide

Proceedings of 5th International Symposium on Material Testing Reactors (ISMTR-5) (Internet), 7 Pages, 2012/10

The JMTR has been utilized for fuel/material irradiation examinations of LWRs, HTGR, fusion reactor as well as for RI productions. The refurbishment of the JMTR was started from the beginning of JFY 2007, and finished in March 2011 as planned schedule. Unfortunately, at the end of the JFY 2010 on March 11, the Great-Eastern-Japan-Earthquake occurred, and functional tests before the JMTR restart were delayed by the earthquake. Moreover, a detail inspection found some damages such as small cracks in the concrete structure, ground sinking around the reactor building. Consequently, the restart will delay from June 2011. Now, the safety evaluation of the facility after the earthquake disaster is being carried out aiming at the restart of the JMTR. The renewed JMTR will be started from JFY 2012 and operated for a period of about 20 years until around JFY 2030. The usability improvement of the JMTR is also discussed with users as the preparations for re-operation.

JAEA Reports

Maintenance of used components in spallation neutron source; Moderator $$cdot$$ reflector and proton beam window

Teshigawara, Makoto; Kinoshita, Hidetaka; Wakui, Takashi; Meigo, Shinichiro; Seki, Masakazu; Harada, Masahide; Ito, Manabu; Suzuki, Toru; Ikezaki, Kiyomi; Maekawa, Fujio; et al.

JAEA-Technology 2012-024, 303 Pages, 2012/07


3 GeV Protons with 1 MW beam power are irradiated to mercury target of spallation neutron source in Materials and Life science Facility (MLF), which is one of facilities of J-PARC. Irradiated components, such as target container, moderator, reflector and proton beam window, are needed to replace periodically due to irradiation damage of high energy protons and neutrons. These used components are replaced remotely because of highly activated. Maintenance scenario was settled so as to handle these components. Required remote handling machines were designed and installed in hot cell and other room of the MLF. We performed remote handling tests by using actual components to confirm the design. We report results, such as replacement procedure, trouble and its solution, etc., for moderator, reflector and proton beam window in order to provide the handling of actual used components.

JAEA Reports

Proceedings of the Specialist Meeting on Mo-99 Production by (n,$$gamma$$) Method; March 9-10, 2012, Yurakucho Asahi Hall, Tokyo, Japan

Ishitsuka, Etsuo; Ishihara, Masahiro; Suzuki, Masahide

JAEA-Review 2012-030, 247 Pages, 2012/07


This report summarizes the documents presented in the Specialist Meeting on $$^{99}$$Mo Production by (n,$$gamma$$) Method, which was held on March 9 to 10, 2012, at the Yurakucho Asahi Hall in Tokyo, hosted by Japan Atomic Energy Agency. The objective of the meeting is to exchange the information of current status, future plan for the $$^{99}$$Mo production, and to make a discussion of "How to cooperate" in each research and test reactors. There were 27 participants from Poland, Kazakhstan, Indonesia, Thailand, Malaysia, Netherlands, Korea and Japan. As a result of this meeting, it was recognized that to push forward the development of $$^{99}$$Mo production by (n,$$gamma$$) method is necessary for the future steady supply of $$^{99}$$Mo. Moreover, an irradiation test using the high density MoO$$_{3}$$ pellet developed by the Japan Atomic Energy Agency was proposed from a viewpoint of a merit for the common irradiation target in each research and test reactors.

JAEA Reports

Proceedings of the 4th International Symposium on Material Testing Reactors; December 5-9, 2011, Oarai, Japan

Ishihara, Masahiro; Suzuki, Masahide

JAEA-Conf 2011-003, 297 Pages, 2012/03


This report is the Proceedings of the 4th International Symposium on Materials Testing Reactors hosted by Japan Atomic Energy Agency (JAEA). The 4th symposium was originally scheduled to be held INVAP in Argentina. However, the aftermath of volcanic explosion at Chili forced the symposium to change place. Total 111 participants attended from Argentina, Belgium, France, Germany, Indonesia, Malaysia, Korea, South Africa, Switzerland, the United State and Japan. This symposium addressed the general topics of "status and future plan of materials testing reactors", "advancement of irradiation technology", "expansion of industry use(RI)", "facility, upgrade, aging management", "new generation MTR", "advancement of PIE technology", "development of advanced driver fuel", and "nuclear human resource development(HRD) for next generation", and 39 presentations were made.

Journal Articles

Training program for students and young engineers in JMTR

Takemoto, Noriyuki; Izumo, Hironobu; Hori, Naohiko; Ishitsuka, Etsuo; Suzuki, Masahide

JAEA-Conf 2011-003, p.265 - 269, 2012/03

The JMTR is expected to be a key infrastructure to contribute the nuclear Human Resource Development (HRD) by a research and On-Job-Training (OJT) in order to support global expansion of nuclear power industry. The training program for Asian young researchers and engineers were started from JFY 2011 in JAEA, and ten trainees from Kazakhstan and Thailand had attended in this program in JFY 2011. In addition, in the nuclear HRD initiative program sponsored by the MEXT, the training course was newly established for domestic students and young engineers from JFY 2010 to JFY 2012. In this course, basic understanding on irradiation test and post irradiation examination is aimed to achieve by overall and practical training such as the neutronic/thermal designs of irradiation capsule, post irradiation examination, measurement and evaluation of neutron fluence, etc. using the JMTR and the related facilities. The 1st training course was held with 10 trainees in JFY 2010. The 2nd and 3rd training courses were also held with 19 trainees and 16 trainees in JFY 2011. From JFY 2012, two courses will be held in every year, and 20 trainees will be accepted in each course.

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