ICMST-Tohoku 2018
Oct. 23 - 26, 2018
Sendai, Japan
ICMST-Shenzhen 2016
Nov 1 - 4, 2016
Shenzhen, China
ICMST-Kobe 2014
Nov 2(Sun) - 5(Wed), 2014
Kobe, Japan
Nuclear Regulation Authority Outline of the New Safety Standards for Light Water Reactors for Electric Power Generation
For Public Comment
Outline of New Safety Standard (Design Basis)
For Public Comment
New Safety Standards (SA) Outline (Draft)
For Public Comment
Outline of New Safety Standard(Earthquake and Tsunami)(DRAFT)

Vol.10 No.2(Aug)
Vol.10 No.1(May)
Vol.9 No.4(Feb)
Vol.9 No.3(Nov)

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Occasional Topics
OTjapan Measures for Tsunami Striking Nuclear Power Station in Japan
Special Article: The Great Tohoku Earthquake (1)
OTjapan The Tragedy of “To Be” Principle in the Japanese Nuclear Industry
EJAMOT_CN3_Figure1_The_outside_view_of_CEFR OTChinaPlanning and Consideration on SFR R&D Activities in China
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Featured Articles
EJAM7-3NT72 A New Mechanical Condition-based Maintenance Technology Using Instrumented Indentation Technique
EJAM7-3NT73 Survey robots for Fukushima Daiichi Nuclear Power Plant

(in English)


Vol.11 No.1previous AASP19(150-151-152-153-154-155)-AA156 NT93

Academic Articles
Vol. 11, No. 1 (2019) p.1-p.45

Special Issue 19

The 4th International Conference on Maintenance Science and Technology (ICMST-Tohoku 2018)


ICMST-Tohoku 2018, the 4th International Conference on Maintenance Science and Technology was held at "Sakura Hall" on Tohoku University Katahira campus in Sendai, Miyagi, Japan between the 23rd and the 26th of October 2018. ICMST-Tohoku 2018 was the latest of a highly successful series which started in Tokyo (Japan, 2012) and continued in Kobe (Japan, 2014) and Shenzhen (China, 2016).

Maintenance is still an uncharted area for humankind, and we have to study energetically. After the Fukushima accident, the credibility of nuclear safety has been an important issue worldwide. The conference continues to be the key forum for scientists and engineers interested in maintenance science and technology for nuclear power plants.

ICMST-Tohoku 2018 featured 101 presentations given to 209 attendees from nine countries. Publication in these special issues was voluntary and after peer review. This could not have been achieved without the very significant efforts of both reviewers and authors. Without this work, these special issues could not exist, and I would like to thanks them on behalf of the Publication Committee. A total of 24 papers are included in two special issues, with 6 papers are included in this issue, and the other 18 papers will be published in the next issue. I hope that all those who attended would share my opinion that ICMST-Tohoku 2018 was a vibrant, exciting and productive conference and that these special issues give some sense of the success of ICMST-Tohoku 2018 to the reader.

Finally, I would like to thank the members of the ICMST International Steering Committee, the Organizing Committee, the Local Organizing Committee and the Secretariat without whose tireless work ICMST-Tohoku 2018 would not have succeeded.

Guest Editor,
Kenji Suzuki

Noriyasu KOBAYASHI, Fumikazu MORIKAWA, Tomoki FUJITA, Daisuke MATSUKAWA, Takashi KASUYAand Kentaro TSUCHIHASHI

We verified that eddy current testing (ECT) has enough detectability for a welded part position of in-core monitor (ICM) housing outside and defects on a heat affected zone (HAZ) in welding of the inner surfaces for a special inspection involved in long-term operation. It is difficult to determine an appropriate inspection area if an actual welded position of an ICM housing is different from a designed position. It is presumed that detectability of ECT is decreased because a HAZ of an ICM housing inner surface is deformed by welding. We conducted a full-scale mock-up test using a simulated ICM housing specimen with a welded part and an ECT system which consisted of a welded part detection probe, a rotational ECT probe and probe moving equipment and confirmed that the ECT detected a welded part position of outside and defects of about 0.5 mm in depth despite existences of inner surface deformations of approximately 1 mm.

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Masayuki KAMAYA and Takao NAKAMURA

Failure probability of static components is used for assessing plant safety or resilience index of nuclear power plants. In this study, a failure probability assessment model was developed that considers the effect of material degradation caused by low-cycle fatigue. Crack initiation due to fatigue damage was assumed and its depth was determined from the magnitude of fatigue damage. Then, crack growth was predicted for seismic loads consisting of a main earthquake and aftershocks. Finally, the failure probability was calculated for the seismic load of various magnitudes. The model was successfully applied to a pipe of the residual heat removal system of a pressurized water reactor power plant. It was shown that the failure probability was hardly affected by the degree of fatigue damage. Although the crack depth had little influence on the fracture strength of the cracked pipe, an increase in the number of aftershocks could increase the probability of leakage.

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Susumu MIURA, Shouji SEKIGUCHI and Kouzou HATTORI,
Ryota OGAWA, Hiroaki FUJIYOSHI, Mitsuyuki SAGISAKA and Yoshihiro ISOBE

Non-destructive evaluation technique was developed for embedded hardware using hammering inspection with AE (Acoustic Emission) sensor. The integrity of the embedded hardware is judged from both the vibration duration of the embedded hardware recorded by the AE sensor and the frequency analysis of the vibration signal. Mockup tests were carried out in order to verify the effectiveness of the technique and to obtain the diagnostic criteria. The technique was then applied to the field inspection.

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Takashi MATSUNAGA, Ryota OGAWA, Mitsuyuki SAGISAKA, and Hiroaki FUJIYOSHI, Yoshihiro ISOBE

Digital hammering inspection system with AE (Acoustic Emission) sensor has been developed and the effects of state, stiffness, etc. on the natural frequency of metal and concrete objects to be inspected were evaluated in terms of improper installations and age-related degradations. The system has been widely applied to social infrastructural diagnosis including expressways (West Nippon Expressway Company Limited, NEXCO-WEST), nuclear power plants (ex. Chubu Electric Power Co., Inc.), reprocessing plant of spent nuclear fuel (Japan Nuclear Fuel Limited) and a successful on-site trial of a new technology of i-Construction led by MLIT (the Ministry of Land, Infrastructure, Transport and Tourism).

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Hidenori SATO, Satoshi SUZUKI, Tsuyoshi UTAGAWA, Masato ITO and Hideo SAKURAI

In order to pursue safety and efficiently manage resources, we are improving our maintenance business process by using information technology (IT) and introducing a work management process (WM process). These efforts have resulted in improvements in managing the duration of safety-equipment unavailability and in addressing non-conformance backlogs.

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Hitomi Ono, Keisuke Takenaka, Tomoaki Kita, Masashi Taniguchi, Daiju Matsumura, Yasuo Nishihata, Ryutaro Hino, Ernst-Arndt Reinecke, Kazuyuki Takase, Hirohisa Tanaka

Safety management technology of hydrogen gas is extremely important not only for nuclear power generation but also for future society. This is international research and development on hydrogen safety technology in which industry, government and academia collaborate. A brand-new passive autocatalytic recombiner (PAR) system utilizing the monolithic “intelligent catalyst” has been studied for the long-term storage of high-concentration radioactive materials related to the decommissioning of nuclear reactors. In a small lab scale test, it was found that this monolithic catalyst can start a hydrogen oxidation reaction from a low temperature of minus 20 ℃. The monolith-type automotive catalyst showed high hydrogen conversion activity from a room temperature in a large-scale reactor of REKO-4 in Jülich (FZJ). It became clear that natural convection by reaction is greatly improved by roughening the cell density of the monolith catalyst especially under static environmental conditions such as in a storage container. Furthermore, this natural convection is strengthened by adopting a chimney, and the hydrogen oxidation reaction per unit time has improved about three times. Taking advantage of this superior catalytic property, we aim to complete the safety technology for storage containers at an early stage and advance the development of highly active catalyst from further low temperature.

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