Report of the design examination and the installation work for the radiation shield at the beam injection area in the 3 GeV synchrotron

Nakanoya, Takamitsu; Kamiya, Junichiro; Yoshimoto, Masahiro; Takayanagi, Tomohiro; Tani, Norio; Kotoku, Hirofumi*; Horino, Koki*; Yanagibashi, Toru*; Takeda, Osamu*; Yamamoto, Kazami

JAEA-Technology 2021-019, 105 Pages, 2021/11

JAEA-Technology-2021-019.pdf:10.25MB

Since a user operation startup, the 3 GeV synchrotron accelerator (Rapid-Cycling Synchrotron: RCS) gradually reinforced the beam power. As a result, the surface dose rate of the apparatus located at the beam injection area of the RCS, such as the magnet, vacuum chambers, beam monitors, etc., increases year by year. The beam injection area has many apparatuses which required manual maintenance, so reducing worker's dose is a serious issue. To solve this problem, we have organized a task force for the installation of the shield. The task force has aimed to optimize the structure of the radiation shield, construct the installation procedure with due consideration of the worker's dose suppression. As the examination result of the shield design, we have decided to adopt removal shielding that could be installed quickly and easily when needed. We carried out shield installation work during the 2020 summer maintenance period. The renewal work required to install the shielding has been carried out in a under high-dose environment. For this reason, reducing the dose of workers was an important issue. So, we carefully prepared the work plan and work procedure in advance. During the work period, we implemented various dose reduction measures and managed individual dose carefully. As a result, the dose of all workers could be kept below the predetermined management value. We had installed removal shielding at the beam injection area in the 2020 summer maintenance period. We confirmed that this shield can contribute to the reduction of the dose during work near the beam injection area. It was a large-scale work to occupy the beam injection area during almost of the summer maintenance period. However, it is considered very meaningful for dose suppression in future maintenance works.

Initiatives to address the lifetime improvement of HBC stripper foil for 3GeV synchrotron of J-PARC

Yoshimoto, Masahiro; Nakanoya, Takamitsu; Yamazaki, Yoshio; Saha, P. K.; Kinsho, Michikazu; Yamamoto, Shunya*; Okazaki, Hiroyuki*; Taguchi, Tomitsugu*; Yamada, Naoto*; Yamagata, Ryohei*

Proceedings of 18th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.850 - 854, 2021/10

no abstracts in English

Proceedings of 2nd JAERI-JNC Joint Conference on Nuclear Safety Research; February 6, 2004, Tokyo

Secretariat of Second JAERI-JNC Joint Conference on Nuclear Safety Research

JAERI-Conf 2004-013, 97 Pages, 2004/08

JAERI-Conf-2004-013.pdf:18.89MB

no abstracts in English

Data list of nuclear power plants in Japan; PWR edition, 1992

Izumi, Fumio; ; Kobayashi, Kensuke;

JAERI-M 92-204, 532 Pages, 1993/01

JAERI-M-92-204.pdf:15.06MB

no abstracts in English

The JAERI tandem accelerator facility

Nuclear Instruments and Methods in Physics Research A, 244, p.13 - 19, 1986/00

https://doi.org/10.1016/0168-9002(86)90729-1

no abstracts in English

Socially constructed resilience by multiple organizations; The Case of Tokai No.2 Power Station

Oba, Kyoko; Yoshizawa, Atsufumi*; Kitamura, Masaharu*

no journal, , 

This paper focuses on the Tokai No.2 Nuclear Power Station, which was hit by earthquakes and subsequent tsunami in the Great East Japan Earthquake in 2011 but swiftly achieved cold shutdown. The earthquake struck the power station just before the scheduled completion of engineering work to raise the walls of the room housing a seawater intake pump. The fact that the work had been applied helped continuous operation of the seawater intake pump, a key piece of equipment for achieving cold shutdown. The power station followed its pre-defined procedure to bring its reactors to cold shutdown. Focusing on the background of the engineering work, which was not mentioned in past reports, this paper analyzes multiple organizations (main actors) based on the concept of Resilience Engineering to reveal how the collaboration between these organizations enhanced the power station's resilience, and considers the potential of such collaboration in boosting the resilience of our society.