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Taguchi, Shigeo; Taguchi, Katsuya; Makino, Risa; Yamanaka, Atsushi; Suzuki, Kazuyuki; Takano, Masato; Koshino, Katsuhiko; Ishida, Michihiko; Nakano, Takafumi; Yamaguchi, Toshiya
Nihon Hozen Gakkai Dai-17-Kai Gakujutsu Koenkai Yoshishu, p.499 - 502, 2021/07
In 2018, Tokai Reprocessing Plan (TRP) shifted to the decommissioning stage. In order to proceed with steady decommissioning work, TRP effort to enhance project management function. This paper describes the establishment and role of the Decommissioning Project Management Office, effectiveness of applying the project management tool and its utilization concept, and the method of materialize the equipment dismantling plan.
Shirai, Nobutoshi; Miura, Yasushi; Tachibana, Ikuya; Omori, Satoru; Wake, Junichi; Fukuda, Kazuhito; Nakano, Takafumi; Nagasato, Yoshihiko
JAEA-Technology 2016-007, 951 Pages, 2016/07
JAEA-Technology-2016-007-01.pdf:11.93MBJAEA-Technology-2016-007-02.pdf:4.7MB
The periodic safety review of TRP is to confirm the safety activities and get effective additional measures the facility safety and its reliability. We implemented 4 items; for (1) evaluation of safety activity implementation, we confirmed we are adequately expanding its safety activities by the necessary documents and schemes. For (2) evaluation of status of safety activities reflecting the latest technical knowledges, we confirmed we reflect latest knowledges for improvement of safety and reliability. For (3) technical evaluation about aging degradation, we can keep the safety of the facilities important to safety and the sea discharge line, under assumption of the present maintenance, because of "focuses for aging degradation". For (4) planning measures about a 10-years-plan that the operator shall implement to keep the facility condition, by the technical evaluation, we found no additional safety plans into maintenance strategies.
Nakano, Takafumi; Sato, Fuminori; Shirozu, Hidetomo; Nakanishi, Ryuji; Fukuda, Kazuhito; Tachibana, Ikuya
Nihon Genshiryoku Gakkai-Shi ATOMO
, 57(1), p.14 - 20, 2015/01
no abstracts in English
Fukuda, Kazuhito; Tomioka, Kenichiro*; Omori, Satoru; Nakano, Takafumi; Nagasato, Yoshihiko
JAEA-Technology 2014-032, 566 Pages, 2014/11
JAEA-Technology-2014-032.pdf:32.45MBJAEA-Technology-2014-032(errata).pdf:9.54MB
The Periodic Safety Review of TRP is assessment of the validity of safety activities in order to get assurance for continuous operation by adding effective items to extract and to execute for TRP safety. We performed 4 items; for (1) evaluation of safety activity at TRP, as we confirmed organization was ordered and managed. For (2) evaluation of status of safety activities reflecting the latest knowledge, we confirmed improvement of safety was continued adequately reflecting from the experience for safety. For (3) technical review on aging for the safety related structures, systems and components, we evaluated the guaranty of safety under assumption of continuous maintenance till the next Periodic Safety Review. For (4) establishment of long term maintenance program, we found no additional activities into maintenance programs, however, for several installations we established a plan and utilized them for reliability.
collisions at 
= 200 and 62.4 GeVAdare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Armendariz, R.*; et al.
Physical Review C, 83(6), p.064903_1 - 064903_29, 2011/06
Times Cited Count：189 Percentile：99.42(Physics, Nuclear)Transverse momentum distributions and yields for 
, and 
in collisions at = 200 and 62.4 GeV at midrapidity are measured by the PHENIX experiment at the RHIC. We present the inverse slope parameter, mean transverse momentum, and yield per unit rapidity at each energy, and compare them to other measurements at different collisions. We also present the scaling properties such as 
and 
scaling and discuss the mechanism of the particle production in collisions. The measured spectra are compared to next-to-leading order perturbative QCD calculations.
and Au+Au collisions at 
= 200 GeVAdare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Aramaki, Y.*; et al.
Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04
Times Cited Count：10 Percentile：52.22(Physics, Nuclear)Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled collisions. Here we extend these studies to two particle correlations where one particle is an electron from the decay of a heavy flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interaction between heavy quarks and the quark-gluon matter. We find the away-side-jet shape and yield to be modified in Au+Au collisions compared to collisions.
Takafumi, Nakano,; Ishida, Michihiko; Kazuyuki, Morimoto,; Inano, Masatoshi; Nojiri, Ichiro
JNC TN8410 2003-017, 190 Pages, 2004/03
JNC-TN8410-2003-017.pdf:6.61MB
Probabilistic Safety Assessment (PSA) methodology has been applied to evaluate the relative importance of safety functions that prevent the progress of event causing to postulate accidents.
The Working Team for Examination of the Sample from Core Shrouds and Primary Loop Recirculation Pipi; Nakajima, Hajime*; Shibata, Katsuyuki; Tsukada, Takashi; Suzuki, Masahide; Kiuchi, Kiyoshi; Kaji, Yoshiyuki; Kikuchi, Masahiko; Ueno, Fumiyoshi; Nakano, Junichi; et al.
JAERI-Tech 2004-015, 114 Pages, 2004/03
JAERI-Tech-2004-015.pdf:38.06MB
The Tokyo Electric Power Company (TEPCO) visually inspected the weld joint of core shroud at Fukushima Dai-ni Nuclear Power Station Unit-2 by a direction of the Nuclear and Industrial Agency, cracks were observed at outer side of the ring weld joint (H3) between a core shroud middle trunk and a middle ring. TEPCO has conducted a material examination with Nippon Nuclear Fuel Development Co. Ltd. (NFD) on the specimen including cracks sampled from the core shroud. The present examination has been performed with the objective to independently investigate and evaluate the materials by jointly attending the examination with NFD from the planning stage. Based on results of the present examination, the probable presence of tensile residual stress by welding process and dissolved oxygen contents in the cooling water, it was shown that the cracks were considered to be stress corrosion cracking (SCC). However, the cause of the cracks needs more consideration on the way of shroud construction.
Nakanishi, Ryuji; Sato, Fuminori; Kosaka, Ichiro; Nakano, Takafumi; Nagasato, Yoshihiko
no journal, ,
no abstracts in English
Taguchi, Katsuya; Nakabayashi, Hiroki; Nakano, Takafumi
no journal, ,
The Tokai Reprocessing Plant (TRP) was taken out of service of spent fuel reprocessing operation and the first decommissioning plan was authorized by the Nuclear Regulatory Agency (NRA) at June 2018. Due to the complexity, numerousness of facilities and various condition of contamination, it would be expected the decommissioning plan requires over 70 years. In the view of maintenance following three major issues were arisen at this time, temporary increase of maintenance and testing works with additional equipment for safety enhancement to the storage of HAW, the ageing management for over 70 years decommissioning period and optimizing the replacement strategy for existing equipment considering of the risk level reduction with progress of the decommissioning plan. The presentation shows our perspective and conceptual procedures to take up these issues.
Nakano, Takafumi
no journal, ,
no abstracts in English
Nakano, Takafumi; Inano, Masatoshi; Aoshima, Atsushi
no journal, ,
no abstracts in English
Tsukada, Takashi; Motooka, Takafumi; Nakano, Junichi; Sato, Tomonori; Hata, Kuniki; Yamamoto, Masahiro
no journal, ,
At the Fukushima Daiichi (1F) nuclear power plant (NPP), the seawater was injected to cool down the reactor cores and fuel assemblies in Spent Fuel Pool (SFP) after the accident in March 2013. Therefore, steel components of Primary Containment Vessel (PCV) and Reactor Pressure Vessel (RPV) and also Zircaloy cladding of fuel assemblies in SFP will be exposed to corrosion environment of diluted seawater and high dose radiation during storage. At JAEA, based on the mid-and-long-term roadmap for decommissioning of the unit 1-4 of 1F NPP, research on the long term integrity of RPV/PCV and fuel assemblies have been carried out from a viewpoint of the effect of seawater and radiation on corrosion. Outline and results of irradiation corrosion test will be presented.
Koshino, Katsuhiko; Shirai, Nobutoshi; Sakaguchi, Shinobu; Shirozu, Hidetomo; Otaki, Miyuki*; Kosaka, Ichiro; Nakano, Takafumi; Nagasato, Yoshihiko; Tachibana, Ikuya
no journal, ,
no abstracts in English
Fukuda, Kazuhito; Tomioka, Kenichiro*; Tachibana, Ikuya; Shirai, Nobutoshi; Kosaka, Ichiro; Nakano, Takafumi; Nagasato, Yoshihiko
no journal, ,
no abstracts in English
Nakano, Takafumi; Fukuda, Kazuhito; Sato, Fuminori; Kosaka, Ichiro; Nagasato, Yoshihiko
no journal, ,
no abstracts in English
Sato, Fuminori; Nakanishi, Ryuji; Kosaka, Ichiro; Nakano, Takafumi; Nagasato, Yoshihiko
no journal, ,
no abstracts in English
Yamamoto, Masahiro; Motooka, Takafumi*; Nakano, Junichi*; Kato, Chiaki; Sato, Tomonori
no journal, ,
About 10 years have passed after Higashi-Nihon earthquake. Decommissioning process of Fukushima Dai-ichi NPS have been continuing day by day. However, some corrosion problems were revealed at the early stage after the accident, because sea water was used for emergency cooling of reactor vessel. In this report, research and development against those corrosion problems by JAEA researchers are introduced briefly. For example, corrosion mechanism and mitigation procedure for spent nuclear fuel pool, reactor vessel and equipment for removal of radioactive materials are summarized.
-ray irradiation on inhibition of steel corrosion in diluted sea waterSato, Tomonori; Kato, Chiaki; Motooka, Takafumi; Ueno, Fumiyoshi; Nakano, Junichi; Kaneko, Tetsuji*; Tanaka, Norihiko*; Kawaharada, Yoshiyuki*; Fujii, Kazumi*; Iwanami, Masaru*; et al.
no journal, ,
no abstracts in English
Nakazawa, Yutaka; Murakami, Manabu; Taguchi, Katsuya; Nakano, Takafumi; Nagasato, Yoshihiko
no journal, ,
JAEA will make a TRP safety policy necessary to adequate the new standard of legal regulation for nuclear facilities and to improve the action based on the decommissioning phase of TRP that counting the nuclear material and importance to control it. I will explain the present TRP situation, selection of important facilities in viewpoint of safety and credible accidents, and the safety policy now planning.
