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Journal Articles

Four-point-bend tests on high-burnup advanced fuel cladding tubes after exposure to simulated LOCA conditions

Narukawa, Takafumi; Amaya, Masaki

Journal of Nuclear Science and Technology, 57(7), p.782 - 791, 2020/07

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

Journal Articles

Experimental validation of tensile properties measured with thick samples taken from MEGAPIE target

Saito, Shigeru; Suzuki, Kazuhiro; Hatakeyama, Yuichi; Suzuki, Miho; Dai, Y.*

Journal of Nuclear Materials, 534, p.152146_1 - 152146_16, 2020/06

 Times Cited Count:0 Percentile:100(Materials Science, Multidisciplinary)

A post-irradiation examination (PIE) was performed on the tensile specimens prepared from the MEGAPIE (MEGAwatt Pilot Experiment) target which were irradiated in flowing lead-bismuth eutectic (LBE). Thicknesses of the specimens were over two times larger than that of the standard specimen. The PIE revealed that the T91 specimens showed a 1.5-2.0 times larger total elongation (TE) compared to the literature values for a specimen with standard t/w (ratio of thickness to width). It could be suggested that the t/w and TE were strongly correlated. Then, we tried to investigate the effects of the t/w on the TE by comparing unirradiated specimens. We found that there was no t/w dependence on the strength and uniform elongation. On the other hand, the TE increases with increasing t/w. Based on the experimental data, we correlated the TE with various specimens t/w to estimate appropriate TE values, including that for the standard specimen.

Journal Articles

Fracture limit of high-burnup advanced fuel cladding tubes under loss-of-coolant accident conditions

Narukawa, Takafumi; Amaya, Masaki

Journal of Nuclear Science and Technology, 57(1), p.68 - 78, 2020/01

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

Journal Articles

Behavior of high-burnup advanced LWR fuel cladding tubes under LOCA conditions

Narukawa, Takafumi; Amaya, Masaki

Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.912 - 921, 2019/09

Journal Articles

Behavior of LWR fuels with additives under reactivity-initiated accident conditions

Mihara, Takeshi; Udagawa, Yutaka; Amaya, Masaki; Taniguchi, Yoshinori; Kakiuchi, Kazuo

Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.544 - 550, 2019/09

Journal Articles

Behavior of high-burnup LWR-MOX fuel under a reactivity-initiated accident condition

Taniguchi, Yoshinori; Udagawa, Yutaka; Mihara, Takeshi; Amaya, Masaki; Kakiuchi, Kazuo

Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.551 - 558, 2019/09

Journal Articles

Quantitative estimation of exposure inhomogeneity in terms of eye lens and extremity monitoring for radiation workers in the nuclear industry

Yoshitomi, Hiroshi; Kowatari, Munehiko; Hagiwara, Masayuki*; Nagaguro, Seiji*; Nakamura, Hajime*

Radiation Protection Dosimetry, 184(2), p.179 - 188, 2019/08

 Times Cited Count:1 Percentile:58.8(Environmental Sciences)

Journal Articles

Oxidation behavior of high-burnup advanced fuel cladding tubes in high-temperature steam

Narukawa, Takafumi; Amaya, Masaki

Journal of Nuclear Science and Technology, 56(7), p.650 - 660, 2019/07

 Times Cited Count:5 Percentile:8.35(Nuclear Science & Technology)

JAEA Reports

Annual report of Nuclear Science Research Institute, JFY2013 & 2014

Nuclear Science Research Institute

JAEA-Review 2018-036, 216 Pages, 2019/03

JAEA-Review-2018-036.pdf:19.22MB

Nuclear Science Research Institute (NSRI) is composed of Planning and Coordination Office, Fukushima Project Team and six departments, namely Department of Operational Safety Administration, Department of Radiation Protection, Engineering Services Department, Department of Research Reactor and Tandem Accelerator, Department of Fukushima Technology Development and Department of Decommissioning and Waste Management, and each departments manage facilities and develop related technologies to achieve the "Middle-term Plan" successfully and effectively. In order to contribute the future research and development and to promote management business, this annual report summarizes information on the activities of NSRI of JFY 2013 and 2014 as well as the activity on research and development carried out by Nuclear Safety Research Center, Advanced Research Center, Nuclear Science and Engineering Center and Quantum Beam Science Center, and activity of Nuclear Human Resource Development Center, using facilities of NSRI.

Journal Articles

Behaviors of high-burnup LWR fuels with improved materials under design-basis accident conditions

Amaya, Masaki; Udagawa, Yutaka; Narukawa, Takafumi; Mihara, Takeshi; Taniguchi, Yoshinori

Proceedings of Annual Topical Meeting on Reactor Fuel Performance (TopFuel 2018) (Internet), 10 Pages, 2018/10

Journal Articles

Behavior of fuel with zirconium alloy cladding in reactivity-initiated accident and loss-of-coolant accident

Fuketa, Toyoshi*; Nagase, Fumihisa

Zirconium in the Nuclear Industry; 18th International Symposium (ASTM STP 1597), p.52 - 92, 2018/01

Extensive research programs have been performed for more than two decades in JAEA and a better understanding has been developed for fuel behavior under accident conditions. The program is comprised of: RIA studies including pulse-irradiation experiments in the NSRR, cladding mechanical tests, and development and verification of a computer code RANNS; LOCA tests including integral thermal shock tests, oxidation rate measurements, and cladding mechanical tests; development and verification of a computer code FEMAXI-6, etc. Data and findings from the research programs provided technical basis directly and indirectly for regulatory criteria in Japan and other countries. This paper reviews and summarizes the major outcome from the research programs and identifies further research needs, as the acceptance technical paper for the Kroll Medal award of ASTM.

Journal Articles

Behavior of high-burnup advanced LWR fuels under design-basis accident conditions

Amaya, Masaki; Udagawa, Yutaka; Narukawa, Takafumi; Mihara, Takeshi; Taniguchi, Yoshinori

Proceedings of 2017 Water Reactor Fuel Performance Meeting (WRFPM 2017) (USB Flash Drive), 10 Pages, 2017/09

JAEA Reports

Fabrication techniques of the sample supporting jigs for Post Irradiation Examination with 3 dimension printer

Miyai, Hiromitsu; Suzuki, Miho; Kanazawa, Hiroyuki

JAEA-Technology 2016-041, 46 Pages, 2017/03

JAEA-Technology-2016-041.pdf:5.54MB

In the Reactor Fuel Examination Facility (RFEF) of Japan Atomic Energy Agency (JAEA), Post Irradiation Examinations (PIEs) have been carried out for a long time in order to verify the reliability and the safety of the nuclear fuels irradiated in nuclear power plants. Samples for the PIEs are small and have various shapes. In order to facilitate the handling of the samples using a manipulator, the several kinds of jigs have been used for PIEs at RFEF those jigs are usually manufactured by machining process. We tried to make the jigs, which is PLA resin, with 3D printer and instead of machining process for the reduction of the manufacturing time and the improvement of the dimensional accuracy of the jig this time. It became clear that the actual dimensions of the jigs manufactured with 3D printer were roughly smaller at the concave section and larger at the convex section compared with the dimensions of the plan. So it is necessary to make a plan for the jigs after consideration of the characteristic of the 3D printer. The jigs can be applied to SEM observation, because the deposition of carbon film onto the jigs was well. And the jigs can be used to for the metallography, because the jigs were applicable without any harmful effects on polishing and etching processes.

Journal Articles

Behavior of high-burnup advanced LWR fuels under accident conditions

Amaya, Masaki; Udagawa, Yutaka; Narukawa, Takafumi; Mihara, Takeshi; Taniguchi, Yoshinori

Proceedings of Annual Topical Meeting on LWR Fuels with Enhanced Safety and Performance (TopFuel 2016) (USB Flash Drive), p.53 - 62, 2016/09

In order to evaluate adequacy of present safety criteria and safety margins in terms of advanced fuels and provide a database for future regulation on them, JAEA started an extensive research program called ALPS-II program, which has been sponsored by NRA, Japan. This program is primarily composed of tests simulating a RIA and a LOCA on the high-burnup advanced fuels irradiated in commercial PWR or BWR. Recently, the failure limits of the high-burnup advanced fuels under RIA conditions were investigated at NSRR, and post-test examinations on the fuel rods after the pulse irradiation tests are being performed. In terms of the simulated LOCA test, integral thermal shock tests and high temperature oxidation tests were carried out at RFEF, and the fracture limits, high temperature oxidation rate, etc. of the high-burnup advanced fuel cladding were investigated. This paper mainly describes some recent experimental results obtained in this program with respect to RIA and LOCA.

JAEA Reports

Assessment report of research and development on "Nuclear Safety Research" in FY2014 (Post- and pre-review report)

Kudo, Tamotsu; Onizawa, Kunio*; Nakamura, Takehiko

JAEA-Evaluation 2015-011, 209 Pages, 2015/11

JAEA-Evaluation-2015-011.pdf:10.36MB

Japan Atomic Energy Agency (JAEA) consulted an assessment committee, "Evaluation Committee of Research and Development (R&D) Activities for Nuclear Safety", for post- and pre-review assessment of R&D on nuclear safety research. In response to JAEA's request, the Committee assessed mainly the progress of the R&D project according to guidelines, which addressed the rationale behind the R&D project, the relevance of the project outcome and the efficiency of the project implementation during the period of the current and next plan. As a result, the Committee concluded that the progress of the R&D project is satisfactory. This report describes the results of evaluation by the Committee. In addition, the appendix of this report contains presentations used for the evaluation, and responses from JAEA on the comments from the member of the Committee.

Journal Articles

Behavior of high burnup advanced fuels for LWR during design-basis accidents

Amaya, Masaki; Udagawa, Yutaka; Narukawa, Takafumi; Mihara, Takeshi; Sugiyama, Tomoyuki

Proceedings of Annual Topical Meeting on Reactor Fuel Performance (TopFuel 2015), Part.2 (Internet), p.10 - 18, 2015/09

Advanced fuels which consist of cladding materials with high corrosion resistance and pellets with lower fission gas release have been developed by utilities and fuel vendors to improve fuel performance even in the high burnup region and also raise the safety level of current nuclear power plants to a higher one. In order to evaluate the adequacy of present safety criteria and safety margins in terms of such advanced fuels and provide a database for future regulation on them, Japan Atomic Energy Agency (JAEA) has started a new extensive research program called ALPS-II program (Phase II of Advanced LWR Fuel Performance and Safety program). This program is primarily composed of tests simulating a reactivity-initiated accident (RIA) and a loss-of-coolant accident (LOCA) on high burnup advanced fuels shipped from European nuclear power plants. This paper describes an outline of this program and some experimental results with respect to RIA and LOCA which have been obtained in this program.

JAEA Reports

Evaluation of the performance of the shields in the EPMAs used for radioactive samples

Matsui, Hiroki; Suzuki, Miho; Obata, Hiroki; Kanazawa, Hiroyuki

JAEA-Technology 2014-017, 57 Pages, 2014/06

JAEA-Technology-2014-017.pdf:20.43MB

The Reactor Fuel Examination Facility in JAEA has been used for Post Irradiation Examinations to verify the reliability and safety of the nuclear fuels irradiated in commercial reactors. EPMA (Electron Probe Micro Analyzer) has been utilized for the qualitative analysis of the fission product in the fuel pellet and the detailed observation of the oxide layers formed at the inner and outer surfaces of fuel cladding. Commercial EPMAs were remodeled so that the EPMAs can be applied for radioactive samples. Several shields was set in the EPMA to avoid the $$gamma$$-rays which radiate from a radioactive sample to the proportional counter in the EPMA. It is important to calculate this shielding performance adequately to maintain the precision of analysis. This report describes the results of re-evaluation of the performance of the shields in the EPMAs in the RFEF by using the Particle and Heavy Ion Transport Code System and the examination results of $$gamma$$-ray effect to the X-ray spectrum data by using a radioactive sample.

JAEA Reports

Design of auxiliary shield for remote controlled metallographic microscope

Matsui, Hiroki; Okamoto, Hisato

JAEA-Technology 2014-015, 43 Pages, 2014/06

JAEA-Technology-2014-015.pdf:7.71MB

The remote controlled optical microscope installed in the lead cell at the Reactor Fuel Examination Facility in Japan Atomic Energy Agency has been upgraded to a higher performance unit to study the effect of the microstructural evolution in clad material on the high burn-up fuel behavior under the accident condition. The optical pass of the new microscope requires a new through hole in the shielding lead wall of the cell. To meet safety regulations, auxiliary lead shieldings were designed to cover the lost shielding function of the cell wall. Particle and Heavy Ion Transport Code System (PHITS) was used to calculate and determine the shape and setting positions of the shielding unit. Seismic assessments of the unit were also performed.

Journal Articles

Examinations of fuel debris samples from Three Mile Island Unit 2

Nagase, Fumihisa

Enerugi To Doryoku, 62(279), p.1 - 7, 2012/11

In the accident at the Fukushima-Daiichi Nuclear Power Plants, fuels were molten due to loss of coolant and heat-up of the reactor core. Information on properties of molten fuels (debris) is important to analyze progress of the accident, estimate the status inside the damaged reactors and work on a plan for debris removal. Extensive examinations have been conducted after the accident at the Three Mile Island Unit 2 (TMI-2) in 1979. The Japan Atomic Energy Agency conducted a part of the examinations in the frame of the OECD/NEA Three Mile Island Vessel Investigation Program. This issue reports outline and the main results of the TMI-2 debris examination programs.

Journal Articles

Improvement of the center boring device for the irradiated fuel pellets

Toyokawa, Takuya; Usami, Koji; Shiina, Hidenori; Onozawa, Atsushi

Proceedings of 49th Conference on Hot Laboratories and Remote Handling (HOTLAB 2012) (Internet), 6 Pages, 2012/09

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