Key role of temperature on delamination in solid-state additive manufacturing via supersonic impact

Wang, Q.*; Ma, N.*; Huang, W.*; Shi, J.*; Luo, X.-T.*; Tomitaka, Sora*; Morooka, Satoshi; Watanabe, Makoto*

Materials Research Letters (Internet), 11(9), p.742 - 748, 2023/09

https://doi.org/https://doi.org/10.1080/21663831.2023.2227221

Dynamic accommodation of internal stress and selection of crystallographic orientation relationship in pearlite

Amemiya, Yutaro*; Nakada, Nobuo*; Morooka, Satoshi; Kosaka, Makoto*; Kato, Masaharu*

Tetsu To Hagane, 105(2), p.314 - 323, 2019/02

https://doi.org/10.2355/tetsutohagane.TETSU-2018-086

For deeper understanding of a dynamic accommodation mechanism of internal stress in pearlite originated from the lattice misfit between ferrite and cementite phases, the lattice parameter ratios of cementite were locally analyzed in detail by using the electron backscatter diffraction (EBSD) technique. The EBSD analysis has revealed that lattice parameter ratios of cementite lamellae obviously differ from those of spheroidized cementite particles, which demonstrates that pearlite has a certain amount of internal stress as long as it maintains lamellar structure. The internal stress in pearlite gradually decreased during isothermal holding at 923 K after pearlitic transformation due to interfacial atomic diffusion of iron atoms. However, comparing with theoretical values under Pitsch-Petch orientation relationship, it was understood that large amount of internal stress had been already accommodated upon pearlitic transformation by introduction of misfit dislocations and structural ledges on ferrite/cementite lamellar interfaces. That is, the internal stress of pearlite is dynamically reduced by two different processes; built-in accommodation upon pearlitic transformation and additional time-dependent relaxation after pearlitic transformation. On the other hand, EBSD analysis and neutron diffraction technique gave remarkably different lattice parameters of cementite. From this result, it is concluded that various crystallographic orientation relationships between ferrite and cementite coexist in pearlite. Furthermore, elastic strain energy analysis suggests that the invariant-line criterion on ferrite/cementite interface plays an important role for the selection of orientation relationships in pearlite.

Preliminary examination about the seal leak using the photocoagulation resin (Joint research)

Ooka, Makoto; Maekawa, Yasunari; Tomizuka, Chiaki; Murakami, Tomoyuki*; Katagiri, Genichi*; Ozaki, Hiroshi*; Kawamura, Hiroshi

JAEA-Technology 2015-003, 31 Pages, 2015/03

JAEA-Technology-2015-003.pdf:3.95MB

An action for the decommissioning of the Fukushima Daiichi Nuclear Power Station (Tokyo Electric Power Company) is pushed forward now. For fuel debris Remove, it is necessary to fill the Primary Containment Vessel (PCV) with water. Because a coolant leaks out from the PCV, it becomes the most important problem to seal leak the coolant. Nuclear Plant Decommissioning Safety Research Establishment has examined the method of seal leak using the photocoagulation resin. However, originally the photocoagulation resin is used as coating or the painting, and the applicability to seal leak water is unknown. This report describes the result that examined the applicability to seal leak using photocoagulation resin.

Internship using nuclear facilities in Oarai Research and Development Center

Takemoto, Noriyuki; Itagaki, Wataru; Kimura, Nobuaki; Ishitsuka, Etsuo; Nakatsuka, Toru; Hori, Naohiko; Ooka, Makoto; Ito, Haruhiko

JAEA-Review 2013-063, 34 Pages, 2014/03

JAEA-Review-2013-063.pdf:8.46MB

Nuclear energy is important from a viewpoint of economy and energy security in Japan. However, the lack of nuclear engineers and scientists in future is concerned after the sever accident of TEPCO's Fukushima Daiichi Nuclear Power Station has occurred. Institute of National Colleges of Technology planned to carry out training programs for human resource development of nuclear energy field including on-site training in nuclear facilities. Oarai Research and Development Center in Japan Atomic Energy Agency cooperatively carried out an internship for nuclear disaster prevention and safety utilizing the nuclear facilities such as the JMTR. Thirty two students joined in total in the internship from FY 2011 to FY2013. In this paper, contents and results of the internship are reported.

Current status of JMTR for restart

Takemoto, Noriyuki; Kimura, Nobuaki; Ooka, Makoto

UTNL-R-0483, p.10_1_1 - 10_1_10, 2013/03

no abstracts in English

Development of simulator for materials testing reactors; Model overview

Kollryd, T.*; Romas, A.*; Porter-Peden, M.*; Takemoto, Noriyuki; Kimura, Nobuaki; Ooka, Makoto; Kaminaga, Masanori; Ishitsuka, Tatsuo*; Tamura, Kazuo*

Proceedings of 5th International Symposium on Material Testing Reactors (ISMTR-5) (Internet), 9 Pages, 2012/10

http://www.murr.missouri.edu/ismtr/papercall/Papers/GSE%20Power/Kollryd_T=PAPER_Dev%20of%20Simulator%20for%20MTRs-Model%20Overview.pdf

A simulator for materials testing reactors has been developed to be utilized for human resource development with an advancement of technology in mind. The simulator is designed based on the JMTR, and the reactor core is modeled with REMARK, in which a 3-dimensional, 4-energy group, time dependent, diffusion theory model is applied. The thermo-hydraulic properties in the reactor vessel are modeled using RELAP5-HD, which is the real-time version of RELAP5-3D code. REMARK interacts with the RELAP5-HD thermal hydraulic model by providing power to the moderator. The RELAP5-HD model, in return, provides thermal hydraulic feedback to the REMARK model. For the primary and secondary cooling loops, main heat exchangers, purification system and cooling towers, the 2-phase, 6-equation matrix solution modeling tool JTopmeret is used. The high fidelity level of modern simulators is not only a valuable tool for human resource training, but also an analysis tool for safety in normal/transient/accident conditions of materials testing reactors.

First test results for the ITER central solenoid model coil

Kato, Takashi; Tsuji, Hiroshi; Ando, Toshinari; Takahashi, Yoshikazu; Nakajima, Hideo; Sugimoto, Makoto; Isono, Takaaki; Koizumi, Norikiyo; Kawano, Katsumi; Oshikiri, Masayuki*; et al.

Fusion Engineering and Design, 56-57, p.59 - 70, 2001/10

https://doi.org/10.1016/S0920-3796(01)00235-6

no abstracts in English

Training for nuclear human resource development at JMTR

Takemoto, Noriyuki; Kimura, Nobuaki; Ooka, Makoto; Ishitsuka, Etsuo; Kaminaga, Masanori; Ishihara, Masahiro; Suzuki, Masahide

no journal, , 

In order to support global expansion of nuclear power industry, the nuclear Human Resource Development (HRD) is addressed one of urgent issues because of the lack of nuclear engineers. In this situation, the training course for foreign young researchers and engineers was held at JMTR in JFY 2012, and 16 trainees from Indonesia, Kazakhstan, Malaysia, Thailand and Poland had studied for 3 weeks. The training course contains basic lecture and practice on the neutronic and thermal calculations for irradiation tests in the JMTR, training of reactor operation by a simulator for materials testing reactors, lecture for Fukushima Dai-ichi NPP accident, etc. The nuclear HRD initiative program sponsored by the MEXT, the training course using the JMTR and the related facilities, has also been carried out in every year since JFY 2010 for domestic students and engineers. The 4th training course with 20 trainees and the 5th training course with 15 trainees were held in JFY 2012.

Current status toward the reoperation of JMTR

Kaminaga, Masanori; Tanimoto, Masataka; Ooka, Makoto; Ishihara, Masahiro; Kusunoki, Tsuyoshi; Komori, Yoshihiro; Suzuki, Masahide

no journal, , 

The Japan Materials Testing Reactor (JMTR) in Japan Atomic Energy Agency (JAEA) is a light water cooled tank type reactor with 50 MW thermal power. From its first criticality in March 1968, the JMTR has been utilized for fuel/material irradiation examinations of LWRs, HTGR, fusion reactor as well as for RI productions. In August 2006, the JMTR operation was once stopped in order to have a check & review for the reoperation which was discussed by internal as well as external committees. As a result of the national discussion, the JMTR was determined, finally, to restart after necessary refurbishment works. The refurbishment was started from the beginning of JFY 2007, and replaced were motors of primary and secondary cooling pumps, nuclear instrumentation system, process control system, safety protection system and so on. The refurbishment was finished in March 2011 taking four years 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, such as cooling system, reactor control system and so on, were delayed by the earthquake. Moreover, a detail inspection found some damages such as small cracks in the concrete structure. Consequently, the restart of the JMTR will delay from June 2011 to this year. Now, the safety evaluation 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. Expected utilization fields after reoperation will be a safety research of LWRs for materials/fuels, basic research for nuclear engineering such as HTGR fuels/materials, fusion reactor materials, industrial use such as production of Mo-99 for medical use, and education & training of nuclear scientists and engineers.

Current status toward the re-operation of JMTR

Kaminaga, Masanori; Tanimoto, Masataka; Ooka, Makoto; Ishihara, Masahiro; Kusunoki, Tsuyoshi; Naito, Akinori; Araki, Masanori

no journal, , 

JMTR in JAEA is a light water cooled tank type reactor with 50MW thermal power. From its first criticality in March 1968, the JMTR has been utilized for fuel/material irradiation examinations of LWRs, HTGR and fusion reactor as well as for RI productions under its transportation advantage that the JMTR and hot laboratory is connected by a canal. In August 2006, the JMTR operation was once stopped in order to have a check & review for the reoperation which was discussed by internal as well as external committees. As a result of the national discussion, the JMTR was determined, finally, to restart after necessary refurbishment works. The refurbishment was started from the beginning of JFY 2007, and replaced were motors of primary and secondary cooling pumps, nuclear instrumentation system, and so on. The refurbishment was finished in March 2011 as planned. 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. Seismic influence evaluation for the JMTR because of the 3.11 earthquake was carried out with directions of the government. As a result, integrity of the JMTR reactor facilities has been evaluated and verified for re-operation. Seismic influence evaluation results were reported to the regulatory agency on Sep.7, 2012. Validation evaluation of the seismic influence evaluation results is still underway by the NRA. On the other hand, new regulatory requirements for research and test reactors will be established on Dec.18, 2013 by the NRA. JMTR will be re-started after the completion of validation evaluation of the seismic influence evaluation results and confirmation of suitability against the new regulatory requirements for research and test reactors by the NRA. The renewed JMTR will be operated for a period of about 20 years until around JFY 2030.