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Collaborative Laboratories for Advanced Decommissioning Science; The University of Tokyo*
JAEA-Review 2022-062, 121 Pages, 2023/03
JAEA-Review-2022-062.pdf:4.78MB
The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2021. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2021, this report summarizes the research results of the "Study on water stopping, repair and stabilization of lower PCV by geopolymer, etc." conducted in FY2021. The present study aims to propose a construction method to stop jet deflectors by improved geopolymer and ultra-heavy muddy water, and to repair the lower part of the dry well. In addition, in order to increase the options for on-site construction in unknown situations such as deposition conditions, we will examine a wide range of construction outside the pedestal, and evaluate the feasibility of the construction method by the latest thermal flow simulation method. When widely constructed, fuel debris and deposits discharged out of the pedestal are coated with water stop and repair materials and become waste ...
Iwasawa, Yuzuru; Sugiyama, Tomoyuki; Abe, Yutaka*
Nuclear Engineering and Design, 386, p.111575_1 - 111575_17, 2022/01
Times Cited Count：3 Percentile：53.91(Nuclear Science & Technology)Hayashi, Makoto*; Okido, Shinobu*; Suzuki, Hiroshi
Quantum Beam Science (Internet), 4(2), p.18_1 - 18_12, 2020/06
Abe, Yuta; Nakagiri, Toshio; Watatani, Satoshi*; Maruyama, Shinichiro*
JAEA-Technology 2017-023, 46 Pages, 2017/10
JAEA-Technology-2017-023.pdf:8.01MB
This is a report on Abrasive Water Jet (AWJ) cutting work carried out on specimen, which was used for Simulated Fuel Assembly Heating Examination by Collaborative Laboratories for Advanced Decommissioning Science (CLADS) molten core behavior analysis group in February 2016. The simulated fuel assembly is composed of Zirconia for the outer crucible/simulated fuel, stainless steel for the control blade and Zircaloy (Zr) for the cladding tube/channel box. Therefore, it is necessary to cut at once substances having a wide range of fracture toughness and hardness. Moreover, it is a large specimen with an approximate size of 300 mm. In addition, epoxy resin has high stickiness, making it more difficult to cut. Considering these effects, AWJ cutting was selected. The following two points were devised, and this specimen could be cut with AWJ. If it was not possible to cut at one time like a molten portion of boride, it was repeatedly cut. By using Abrasive Suspension Jet (ASJ) system with higher cutting ability than Abrasive Injection Jet (AIJ, conventional method) system, cutting time was shortened. As a result of this work, the cutting method in Simulated Fuel Assembly Heating Examination was established. Incidentally, in the cutting operation, when the cutting ability was lost at the tip of the AWJ, a curved cut surface, which occurs when the jet flowed away from the feeding direction, could be confirmed at the center of the test body. From the next work, to improve the cutting efficiency, we propose adding a mechanism such as turning the cutting member itself for re-cutting from the exit side of the jet and appropriate traverse speed to protect cut surface.
Nakamura, Yasuyuki; Iwai, Hiroki; Tezuka, Masashi; Sano, Kazuya
JAEA-Technology 2015-055, 89 Pages, 2016/03
JAEA-Technology-2015-055.pdf:17.54MB
It was reported that Fukushima Daiichi Nuclear Power Station (1F) had lost the cooling function of the reactor by the Tohoku Earthquake. It is assumed that the core internals became narrow and complicated debris structure mixed with the molten fuel. In consideration of the above situations, the AWJ cutting method, which has features of the long work distance and little heat effect for a material, has been developed for the removal of the molten core internals through cutting tests for 3 years since FY 2012. And it was confirmed that AWJ cutting method is useful for the removal of the core internals etc. The results in FY 2012 were reported in "R&D of the fuel debris removal technologies by abrasive water jet cutting technology (JAEA-Technology 2013-041)" and this report summarizes the results of FY 2012, 2013 and 2014 in this report. It was confirmed the possibility to apply the removal work of the fuel debris and the core internals.
Shimada, Hiroyuki*; Fukao, Taishi*; Minami, Hirotake*; Ukai, Masatoshi*; Fujii, Kentaro; Yokoya, Akinari; Fukuda, Yoshihiro*; Saito, Yuji
Journal of Chemical Physics, 141(5), p.055102_1 - 055102_8, 2014/08
Times Cited Count：16 Percentile：53.96(Chemistry, Physical)Shibamoto, Yasuteru
JAERI-Research 2005-016, 127 Pages, 2005/08
JAERI-Research-2005-016.pdf:4.54MB
no abstracts in English
Takeuchi, Suehiro; Nakanoya, Takamitsu; Kabumoto, Hiroshi; Yoshida, Tadashi
Nuclear Instruments and Methods in Physics Research A, 513(3), p.429 - 438, 2003/11
Times Cited Count：3 Percentile：27.69(Instruments & Instrumentation)At the JAERI Tandem accelerator, an acceleration tube replacing plan is proceeding to increase the acceleration voltage toward 20 MV. Lengthy conditioning is generally necessary for a large tube system. We had an idea to clean the tubes with high-pressure water-jet rinsing before installation. We cleaned tubes and tested them at 1 MV and 3 MV. The both results exhibited that the voltages went beyond the rated voltages and discharge activities were much less than the old records. During the test of new tubes at 3 MV, the conditioning proceeded well and an extremely stable condition was fulfilled within 24 hours. In conclusion, the cleaning was found to be a very promising way to improve high-voltage performance of the tubes in a large tube system.
Takeuchi, Suehiro; Nakanoya, Takamitsu; Kabumoto, Hiroshi; Ishizaki, Nobuhiro; Matsuda, Makoto; Tsukihashi, Yoshihiro; Kanda, Susumu; Tayama, Hidekazu; Abe, Shinichi; Yoshida, Tadashi
Dai-14-Kai Kasokuki Kagaku Kenkyu Happyokai Hokokushu, p.308 - 310, 2003/00
no abstracts in English
Koshizuka, Seiichi*; Ikeda, Hirokazu*; Liu, J.*; Oka, Yoshiaki*
JAERI-Tech 2002-013, 60 Pages, 2002/03
JAERI-Tech-2002-013.pdf:3.16MB
no abstracts in English
Tachibana, Mitsuo; Shiraishi, Kunio; Yanagihara, Satoshi
JAERI-Tech 2001-014, 42 Pages, 2001/03
In the JPDR dismantling demonstration project, the dismantling activities were conducted for the purpose of verification of remote dismantling machines and collection of various kinds of data on work activities. These lessons were categorized into safety consideration, waste treatment and work efficiency by analyzing the data on work activities. Exemplified are necessities of facility information, efficiency of mock-up tests for evaluation of remote dismantling procedures. There will be useful for implementing other decommissioning projects in safe and efficiency. This report describes the measure taken for remote dismantling activities and the lessons learned from the dismantling activities.
Nakamura, Hiroshi; Ida, Mizuho*; Nakamura, Hiroo; Nakamura, Hideo; Ezato, Koichiro; Akiba, Masato
JAERI-Research 2000-068, 30 Pages, 2001/02
JAERI-Research-2000-068.pdf:3.88MB
no abstracts in English
Ito, Kazuhiro*; Tsuji, Yoshiyuki*; Nakamura, Hideo; Kukita, Yutaka*
9th Int. Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-9)(CD-ROM), 16 Pages, 1999/00
no abstracts in English
Nakamura, Hideo; Ito, Kazuhiro*; Kukita, Yutaka*; *; ; Maekawa, Hiroshi; Katsuta, Hiroji
Journal of Nuclear Materials, 258-263, p.440 - 445, 1998/00
Times Cited Count：7 Percentile：53.8(Materials Science, Multidisciplinary)no abstracts in English
Nakamura, Hideo; *; Kukita, Yutaka*; *; ; Maekawa, Hiroshi
Eighth Int. Topical Meeting on Nuclear Reactor Thermal-Hydraulics (NURETH-8), 3, p.1268 - 1275, 1997/00
no abstracts in English
Noguchi, Hiroshi
Nihon Genshiryoku Gakkai-Shi, 39(11), p.915 - 916, 1997/00
no abstracts in English
Ogawa, Masuro; Kunugi, Tomoaki
Fusion Engineering and Design, 29, p.233 - 237, 1995/00
Times Cited Count：9 Percentile：66.33(Nuclear Science & Technology)no abstracts in English
Fujiki, Kazuo; ; ;
Proc. of the Int. Conf. on Dismantling of Nuclear Facilities; Policies-Techniques, p.219 - 232, 1992/00
no abstracts in English
Nakamura, Hisashi; *; Yanagihara, Satoshi
Nuclear Technology, 86, p.168 - 178, 1989/08
Times Cited Count：8 Percentile：67.28(Nuclear Science & Technology)no abstracts in English
; ; Yahiro, Teruo*
2nd Pacific RIM Int. Conf. on Water JET Cutting, 11 Pages, 1989/00
no abstracts in English
