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Shibata, Ryodai; Amano, Tsukasa; Yamada, Hiroyuki; Miyaji, Noriko; Nakamura, Hironobu
Dai-44-Kai Nihon Kaku Busshitsu Kanri Gakkai Nenji Taikai Kaigi Rombunshu (Internet), 4 Pages, 2023/11
In April 2020, JAEA has been introduced Physical Protection Corrective Action Program (PPCAP) with full-scale. It was needed to introduce unified operation for six sites with different business scales, and headquarters developed the common guideline. There was an impression that physical protection activities were carried out by a limited number of employees. Therefore, a problem was to root and activate PPCAP activities among all employees in order to make them effective. Five activities were implemented to solve this problem. As a result, more than 3,700 condition reports (CR) have been collected for 4 years. This paper reports on the activities related to the PPCAP that have been implemented at JAEA.
Amano, Tsukasa; Shibata, Ryodai; Sato, Yoshiharu; Yamazaki, Katsuyuki; Shiromo, Hideo; Nakamura, Hironobu
Proceedings of INMM & ESARDA Joint Annual Meeting 2023 (Internet), 6 Pages, 2023/05
In Japan, about 10 years have passed since the law obligated nuclear operators to develop and maintain a nuclear security culture. During this period, the global nuclear situation has changed significantly, and it is becoming important to maintain a stance that emphasizes compliance with regulations and nuclear security culture. In JAEA, the policy of legal compliance and developing nuclear security culture is determined by the president of JAEA. For legal compliance and developing nuclear security culture, many activities are carried out based on that policy. Finally, these activities are evaluated and improved it every year. Case study is the one of activities that can obtain skills for legal compliance and developing nuclear security culture, such as sensitivity of nuclear security risks, correct understanding of the laws. The procedure for the case study was created with reference to a method called KY-Training which is often applied to safety training program in Japan. KY-Training is a training that participants (groups) can reach the conclusion how to respond to cases through four questions. Firstly, participants are given illustrations and descriptions which has potential of nuclear security risks. Then, participants make discussion according to four questions. Consequently, participants can effectively become aware of nuclear security risks. In the 2022 case study, we prepared 23 cases so that they can select choose freely according to role of participants such as in charge of nuclear security, guards, general employees. Finally, participants are asked to fill a questionnaire to evaluate effectiveness of case study. The result of questionnaires indicated that the case study was able to lead to improvement sensitivity of nuclear security risks and correct understanding of the laws. Overall, case study results suggested that JAEA's efforts were implying sufficiently to develop and maintain a nuclear security culture.
Amano, Tsukasa; Sato, Yoshiharu; Shibata, Ryodai; Yamazaki, Katsuyuki; Shiromo, Hideo; Nakamura, Hironobu
Dai-43-Kai Nihon Kaku Busshitsu Kanri Gakkai Nenji Taikai Kaigi Rombunshu (Internet), 4 Pages, 2022/11
About ten years have passed since the introduction of nuclear security compliance and security culture development activities. While there have been changes in domestic and international situations, it is essential for nuclear security that the entire organization maintains an attitude that emphasizes compliance with laws and regulations and nuclear security. JAEA has been effectively implementing various activities with evaluation and improvement. Especially, e-learning which combines education and awareness, case studies, and internal audits are considered effective in maintaining nuclear security compliance and security culture development activities.
Yuki, Kazuhisa*; Hasegawa, Shunsuke*; Sato, Tsukasa*; Hashizume, Hidetoshi*; Aizawa, Kosuke; Yamano, Hidemasa
Nuclear Engineering and Design, 241(11), p.4544 - 4550, 2011/11
Times Cited Count：32 Percentile：89.69(Nuclear Science & Technology)Ebara, Shinji*; Aoya, Yuta*; Sato, Tsukasa*; Hashizume, Hidetoshi*; Yuki, Kazuhisa*; Aizawa, Kosuke; Yamano, Hidemasa
Journal of Fluids Engineering, 132(11), p.111102_1 - 111102_7, 2010/11
Times Cited Count：9 Percentile：44.78(Engineering, Mechanical)A multi-elbow piping system is adopted for the Japan Sodium-cooled Fast Reactor (JSFR) cold-legs. Flow Induced Vibration (FIV) is considered to appear due to complex turbulent flow with very high Reynolds number in the piping. In this study, pressure measurement for a single elbow flow is conducted to elucidate pressure fluctuation characteristics originated from turbulent motion in the elbow, which lead potentially to the FIV. Two different scale models, 1/7 and 1/14-scale simulating the JSFR cold-leg piping, are tested experimentally to confirm whether a scale effect in pressure fluctuation characteristics exists. A distinguishing peak can be seen in each power spectrum density (PSD) profile of pressure fluctuation obtained in and downstream of the flow separation region for both scaled models. When nondimensionalized, the PSD profiles show good correspondence regardless of scale model and even of Reynolds number simulated in this study.
Ebara, Shinji*; Aoya, Yuta*; Sato, Tsukasa*; Hashizume, Hidetoshi*; Yuki, Kazuhisa*; Aizawa, Kosuke; Yamano, Hidemasa
Proceedings of 18th International Conference on Nuclear Engineering (ICONE-18) (CD-ROM), 9 Pages, 2010/05
In this study, pressure measurement test is conducted to find out the FIV characteristic features related to the elbow turbulent flow, using 1/7 scale experimental loop simulating the JSFR cold leg piping. As the first step of multielbow piping, pressure measurement for single elbow was performed. The same measurement procedure was taken as a 1/15 scale experiment to assess the influence originated from the different scale flow at the same Reynolds number.
Yuki, Kazuhisa*; Hasegawa, Shunsuke*; Sato, Tsukasa*; Hashizume, Hidetoshi*; Aizawa, Kosuke; Yamano, Hidemasa
Proceedings of 13th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-13) (CD-ROM), 11 Pages, 2009/09
In this study, the flow structures in a 3-dimentionally connected dual elbow, which simulates a part of the cold leg, are visualized by PIV measurement, and it is discussed on the detailed flow transition from the 1st elbow to the 2nd elbow and the generation of unsteady flow such as a separation that influences flow-induced vibration. Experimental apparatus has a 1/15 scale test section of actual design whose inner diameter and curvature radius ratio are 56mm and 1.0, respectively. For visualization without any image distortion, matched refractive-index PIV measurement is carried out using NaI solution as the working fluid. The Reynolds number is 50,000, and the inlet flow condition to the test section is a fully developed turbulent flow. It is confirmed that it generates a separation along the inner wall of the 1st elbow and one large swirling flow in the 2nd elbow. Furthermore, unsteady flow formed in and/or behind the separation region is transported downstream and flows into the center area of the 2nd elbow.
Yoshida, Kazuhiro*; Yuki, Kazuhisa*; Sato, Tsukasa*; Hashizume, Hidetoshi*; Yamano, Hidemasa; Kotake, Shoji
no journal, ,
Flow dynamics in an elbow pipe has been observed by a PIV flow visualization experiments with a 1/15 scale test facility simulating a cold-leg piping in a sodium-cooled fast reactor. This paper also reports the overview of the facility of an upcoming 1/7 scale test and its plan.
Yuki, Kazuhisa*; Sato, Tsukasa*; Yoshida, Kazuhiro*; Hashizume, Hidetoshi*; Aizawa, Kosuke; Yamano, Hidemasa
no journal, ,
To investigate the flow pattern in the cold-leg (multi-elbow geometry) of a sodium-cooled fast reactor, a 1/7-scale water experimental facility was made in this study. First of all, the flow pattern in a single elbow was measured by a PIV technique.
Sato, Tsukasa*; Ebara, Shinji*; Hashizume, Hidetoshi*; Yusa, Noritaka*; Yuki, Kazuhisa*; Aizawa, Kosuke; Yamano, Hidemasa
no journal, ,
To clarify a flow pattern in a multiple elbow pipe of cold-leg in sodium-cooled fast reactor, the 1/7 scale flow experiment was performed as the first step to measure the flow velocity distribution in a single elbow pipe under Re=1
10 by using the PIV technique.
Aoya, Yuta*; Sato, Tsukasa*; Ebara, Shinji*; Hashizume, Hidetoshi*; Yuki, Kazuhisa*; Aizawa, Kosuke; Yamano, Hidemasa
no journal, ,
In order to clarify the hydraulic and vibration behaviors in the primary cooling piping, a flow-induced vibration test with water has been begun using a 1/7-scale and a 1/15-scale L-shaped elbow test section, which simulated the JSFR hot-leg piping. The peak of St number 0.5 was confirmed in both experiments.
Ebara, Shinji*; Sato, Tsukasa*; Hashizume, Hidetoshi*; Aizawa, Kosuke; Yamano, Hidemasa
no journal, ,
To clarify a complex flow in a cold-leg piping of a sodium-cooled fast reactor, flow experiments were conducted by using a 1/7-scale model of the piping with single and dual elbow. Flow fields with intense unsteadiness including flow separation and separation vortices in high Reynolds number region were evaluated by means of PIV measurement. In addition, an effect of multiple elbows was verified by comparing results of the single elbow to those of the dual elbow.
Tokiwa, Tetsuya; Niizato, Tadafumi; Amano, Kenji; Akamine, Shinnosuke*; Tanabe, Kinya*; Nakatsukasa, Masashi*; Yamada, Yasuhiro*
no journal, ,
no abstracts in English
Matsuzaki, Tatsuji; Tokiwa, Tetsuya; Nakatsukasa, Masashi*; Yamada, Yasuhiro*; Akamine, Shinnosuke*; Amano, Kenji; Niizato, Tadafumi
no journal, ,
no abstracts in English
Nakamura, Hironobu; Amano, Tsukasa
no journal, ,
At the request of the University of Tokyo, we conduct a lecture entitled "The Physical Protection of Nuclear Material in the Nuclear Facilities" at the "2020 Nuclear Special Lecture". In this lecture, each physical protection measures stipulated by domestic laws will be explained. In the explanation, specific examples will be given for each physical protection measures such as area-setting and access-control for the physical protection of nuclear materials. Especially, among the physical protections measures, nuclear-security-culture-activities and measures against insider-threats will be introduced together with the efforts of JAEA.
