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Morita, Hisashi; Daigo, Fumihisa; Sayato, Natsuki; Watahiki, Shunsuke; Kojima, Kazuki; Nakayama, Kazuhiko; Ide, Hiroshi
JAEA-Technology 2021-030, 166 Pages, 2022/05
JAEA-Technology-2021-030.pdf:3.65MB
When the roof of the JMTR Hot Laboratory (HL) building was repaired for rain leaks in January, 2015, thinning was found at one of the anchor bolts on base of the HL exhaust stack. Moreover, the thinning of some anchor bolts and gaps between the anchor bolt nuts and flange plate was found in the later investigation for the exhaust stack. Since the possibility of the exhaust stack collapsing cannot be denied, it was removed. Therefore, it became necessary to rebuild a new exhaust stack as soon as possible. The design of the new exhaust stack was based on the measures to prevent rainwater intrusion into the base, which was the cause of the thinning of the anchor bolts found in the investigation, and on the new regulatory standards established after the accident at the Fukushima Daiichi Nuclear Power Station. Furthermore, since the new exhaust stack corresponds to buildings and structures that must undergo building confirmation, the soundness of the new exhaust stack against seismic force and wind load was evaluated based on the Building Standards Law and the Stack Structure Design Guideline. This report described the basic design of the new exhaust stack.
Ishitsuka, Etsuo; Motohashi, Jun; Hanawa, Yoshio; Komeda, Masao; Watahiki, Shunsuke; Mukanova, A.*; Kenzhina, I. E.*; Chikhray, Y.*
JAEA-Technology 2014-025, 77 Pages, 2014/08
JAEA-Technology-2014-025.pdf:43.46MB
It has been shown that tritium concentration in the primary coolant of the JMTR and JRR-3M increases during its operation. In this report, to clarify the tritium sources, the tritium release rate into the primary coolant in each operation cycle for the JMTR, JRR-3M and JRR-4 was evaluated. As a result, the tritium release rate is 
8 Bq/Wd in the JRR-4, which has not the beryllium core components installed, and no increase in the tritium concentration during reactor operation is observed. In contrast, the tritium release rate is about 10
95 and 60140 Bq/Wd in the JRR-3M and JMTR respectively, which cores contain beryllium components, and where the tritium content increases while reactor operates. It is also observed that the amount of released tritium is lower in the case of new beryllium components installation, and increases with the reactor operating cycle.
Kawamata, Takanori; Oto, Tsutomu; Ogasawara, Yasushi; Watahiki, Shunsuke; Araki, Daisuke
UTNL-R-0486, p.8_1 - 8_10, 2014/03
no abstracts in English
Watahiki, Shunsuke; Hanakawa, Hiroki; Imaizumi, Tomomi; Nagata, Hiroshi; Ide, Hiroshi; Komukai, Bunsaku; Kimura, Nobuaki; Miyauchi, Masaru; Ito, Masayasu; Nishikata, Kaori; et al.
JAEA-Technology 2013-021, 43 Pages, 2013/07
JAEA-Technology-2013-021.pdf:5.12MB
The number of research reactors in the world is decreasing because of their aging. On the other hand, the necessity of research reactor, which is used for human resources development, progress of the science and technology, industrial use and safety research is increasing for the countries which are planning to introduce the nuclear power plants. From above background, the Neutron Irradiation and Testing Reactor Center began to discuss a basic concept of Multipurpose Compact Research Reactor (MCRR) for education and training, etc., on 2010 to 2012. This activity is also expected to contribute to design tool improvement and human resource development in the center. In 2011, design study of reactor core, irradiation facilities with high versatility and practicality, and hot laboratory equipment for the production of Mo-99 was carried out. As the result of design study of reactor core, subcriticality and operation time of the reactor in consideration of an irradiation capsule, and about the transient response of the reactor to the reactivity disturbance during automatic control operation, it was possible to do automatic operation of MCRR, was confirmed. As the result of design study of irradiation facilities, it was confirmed that the implementation of an efficient mass production radioisotope Mo-99 can be expected. As the result of design study with hot laboratory facilities, Mo-99 production, RI export devised considered cell and facilities for exporting the specimens quickly was designed.
Watahiki, Shunsuke; Hanawa, Yoshio; Asano, Norikazu; Hiyama, Kazuhisa; Ito, Sachito; Tsuboi, Kazuaki; Fukasaku, Akitomi
JAEA-Review 2012-013, 92 Pages, 2012/03
JAEA-Review-2012-013.pdf:6.74MB
This replacement work was carried out under refurbishment plan of JMTR for beryllium distortion draw to acceptable limit. And gamma-ray shield refurbishment was carried out the view point of prevention maintenance in consideration of operation plan. Fabrication of beryllium frame and gamma-ray shield was spent for two years it was finished in February, 2010. It took five months to replacement work from January 2010. In this report is presented fabrication and replacement work of beryllium frame and gamma-ray shield.
Imaizumi, Tomomi; Miyauchi, Masaru; Ito, Masayasu; Watahiki, Shunsuke; Nagata, Hiroshi; Hanakawa, Hiroki; Naka, Michihiro; Kawamata, Kazuo; Yamaura, Takayuki; Ide, Hiroshi; et al.
JAEA-Technology 2011-031, 123 Pages, 2012/01
JAEA-Technology-2011-031.pdf:16.08MB
The number of research reactors in the world is decreasing because of their aging. However, the planning to introduce the nuclear power plants is increasing in Asian countries. In these Asian countries, the key issue is the human resource development for operation and management of nuclear power plants after constructed them, and also the necessity of research reactor, which is used for lifetime extension of LWRs, progress of the science and technology, expansion of industry use, human resources training and so on, is increasing. From above backgrounds, the Neutron Irradiation and Testing Reactor Center began to discuss basic concept of a multipurpose low-power research reactor for education and training, etc. This design study is expected to contribute not only to design tool improvement and human resources development in the Neutron Irradiation and Testing Reactor Center but also to maintain and upgrade the technology on research reactors in nuclear power-related companies. This report treats the activities of the working group from July 2010 to June 2011 on the multipurpose low-power research reactor in the Neutron Irradiation and Testing Reactor Center and nuclear power-related companies.
Watahiki, Shunsuke; Asano, Norikazu; Hanawa, Yoshio; Gorai, Shigeru; Nishiyama, Yutaka; Tsuboi, Kazuaki
JAEA-Review 2010-019, 65 Pages, 2010/07
JAEA-Review-2010-019.pdf:7.25MB
JMTR secondary cooling system piping and a cooling tower were inspected from the view point of long term utilization before the renewal work for the secondary cooling system of the JMTR on FY 2008. As the result, it was confirmed that crack, swelling, and exfoliations in inner of piping lining, and decay and dryness of wood in the upper part of the cooling tower. From the result of this inspection some facilities and machinery were repaired or replaced from the view point of preventive maintenance.
Ebisawa, Hiroyuki; Hanakawa, Hiroki; Asano, Norikazu; Kusunoki, Hidehiko; Yanai, Tomohiro; Sato, Shinichi; Miyauchi, Masaru; Oto, Tsutomu; Kimura, Tadashi; Kawamata, Takanori; et al.
JAEA-Technology 2009-030, 165 Pages, 2009/07
JAEA-Technology-2009-030.pdf:69.18MB
The condition of facilities and machinery used continuously were investigated before the renewal work of JMTR on FY 2007. The subjects of investigation were reactor building, primary cooling system tanks, secondary cooling system piping and tower, emergency generator and so on. As the result, it was confirmed that some facilities and machinery were necessary to repair and others were used continuously for long term by maintaining on the long-term maintenance plan. JMTR is planed to renew by the result of this investigation.
Watahiki, Shunsuke; Saito, Takashi; Tsuchiya, Kunihiko; Ohara, Hiroshi; Iimura, Koichi
JAEA-Technology 2008-044, 42 Pages, 2008/06
JAEA-Technology-2008-044.pdf:5.43MB
This report is described for the development of nicrosil-nisil type multi-paired thermocouple which was usable at over 1000 degrees under the neutron irradiation environment. Developed nicrosil-nisil type multi-paired thermocouple has maximum 7 hot junctions in axial direction in a sheath. Though the design, trial production and out-pile tests, its productivity and electric performances were confirmed, and the production method was established.
Taguchi, Taketoshi; Hanawa, Yoshio; Watahiki, Shunsuke; Tsuchiya, Kunihiko
JAEA-Technology 2008-041, 23 Pages, 2008/06
JAEA-Technology-2008-041.pdf:3.76MB
Beryllium has been utilized as a reflector in a number of material testing reactors because of low parasitic capture cross section for thermal neutrons and good neutron elastic scattering characteristics. Beryllium frames and beryllium reflectors, which have been utilized as neutron reflector in Japan JMTR, were fabricated beryllium metals. Especially, it is necessary to exchange the beryllium frames every fixed period. Therefore, preliminary irradiation test of beryllium metals (S-200F and S-65C) was performed in JMTR for development on long life of beryllium reflectors. The post irradiation examinations (PIEs) were carried out for the effect on the properties of these irradiated beryllium metals. In these PIEs, size change of the irradiated beryllium was measured with the specimens for bending. This report is described development of the high accuracy measurement device.
Hanawa, Yoshio; Taguchi, Taketoshi; Tsuboi, Kazuaki; Saito, Takashi; Ishikawa, Kazuyoshi; Watahiki, Shunsuke; Tsuchiya, Kunihiko
JAEA-Technology 2008-039, 53 Pages, 2008/06
JAEA-Technology-2008-039.pdf:6.18MB
Beryllium has been utilized as a moderator and/or reflector in a number of material testing reactors. Beryllium frames and beryllium reflectors, which have been utilized as neutron reflector in Japan Materials Testing Reactor (JMTR) in JAEA, were fabricated beryllium metals of S-200F grade. Especially, it is necessary to exchange the beryllium frames every fixed period and there frames were exchanged six times up to the JMTR operation periods of 165 cycles. Therefore, preliminary irradiation test of beryllium metals was performed from 162 to 165 cycles of JMTR operations as a part of development on long life of beryllium reflectors. Two kinds of beryllium metals (S-200F and S-65C) were prepared in this test. This report is described the design study and fabrication of irradiation capsule of beryllium metals and dismount device of irradiation capsule.
Hanakawa, Hiroki; Watahiki, Shunsuke; Echigoya, Shinichi; Miyazawa, Masataka
no journal, ,
no abstracts in English
Watahiki, Shunsuke; Nakamichi, Masaru; Naka, Michihiro; Saito, Takashi; Ide, Hiroshi; Miyazawa, Masataka; Ishihara, Masahiro; Kawamura, Hiroshi
no journal, ,
The development of in-core remote sensing Technology is essential to aim at the realizayion of advanced irradiation examination in the new JMTR. By observing the in-core on real time and taking out nucleus and thermal information as optical information, the technology may be able to detect a very small change of the in-core, which is undetectable by the usual instrumentation. As a result, a highly accurate irradiation examination can be done. In the present study(work), the spent fuel kept in the spent fuel rack in the canal(water way) of JMTR was recorded with a video camera(visible light), and the brightness of Cherenkov radiation was evaluated from the radiation the obtained image.
Ide, Hiroshi; Ishitsuka, Etsuo; Watahiki, Shunsuke; Saito, Takashi; Inaba, Yoshitomo; Kawamura, Hiroshi
no journal, ,
no abstracts in English
Oto, Tsutomu; Nemoto, Hiroyoshi; Kimura, Tadashi; Watahiki, Shunsuke; Hasegawa, Teiji; Ouchi, Takuya; Echigoya, Shinichi; Fukasaku, Akitomi
no journal, ,
no abstracts in English
Asano, Norikazu; Kurosawa, Akihiko; Yanai, Tomohiro; Watahiki, Shunsuke; Kameyama, Yasuhiko; Onoue, Ryuji; Tobita, Kenji; Fukasaku, Akitomi
no journal, ,
no abstracts in English
Watahiki, Shunsuke; Yamaura, Takayuki; Kusunoki, Tsuyoshi
no journal, ,
The Japan Materials Testing Reactor (JMTR) had been operated for 38 years with 165 cycles for various users since the first criticality in 1968. Japan Atomic Energy Agency (JAEA) decided to refurbish the JMTR for long-term operation. The JMTR has been in an extended shutdown period since August, 2006 for its refurbishment, and will restart in 2012. In order to enhance the operational capability of JMTR, equipments to be renewed were selected based on the evaluation on its damage and wear in term of aging and so on. As for the safety management during reactor operation, the facility periodical own inspection and daily inspection is carried out for the purpose of maintaining soundness and reliability of facility and equipments. The safety management during reactor shutdown is also carried out as well as it of reactor operation term. Long-term safety operation of the JMTR will be realized by the refurbishment on the appropriate components with the justified inspection and the renewal work. For the influence of the earthquake, the investigation into integrity of JMTR facilities has been carried out until now.
Watahiki, Shunsuke; Ide, Hiroshi; Hanakawa, Hiroki; Yamaura, Takayuki; Kaminaga, Masanori
no journal, ,
no abstracts in English
Hanakawa, Hiroki; Watahiki, Shunsuke; Ide, Hiroshi; Kitagishi, Shigeru; Imaizumi, Tomomi; Araki, Daisuke; Tobita, Masahiro; Yamaura, Takayuki; Kaminaga, Masanori
no journal, ,
On 18th December 2013, the new regulatory requirements for Japanese research reactor were enforced by the Nuclear Regulation Authority in Japan. This new regulatory requirements are also applied to any research reactor in Japan, even if licensed research reactor. Thus the verification of conformity in the JMTR facilities to the new regulatory requirements was carried out. In this reports, the safety assessment against the beyond design basis accident will be described. At first, events tree analyses were carried out to select beyond design basis accidents. From these analyses, it was confirmed that 8 events can be representative cases. These events were analyzed from the viewpoints of public dose exposer. As the result of analysis, it was confirmed that 3 events out of 8 has a possibility to give the considerable public dose exposer so that the counter measerments were taken account to reduce the dose exposer to acceptable limit.