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Okabe, Ayao; Onuki, Koji; Kikuchi, H.; M.Uchihashi; Nishibayashi, Yohei; Ikeda, Makinori; Miyake, Osamu
JNC TN2400 2003-005, 62 Pages, 2004/03
JNC-TN2400-2003-005.pdf:2.41MB
Sodium combustion analyses were performed using ASSCOPS version 2.1 in order to obtain background data for evaluating validity of the mitigation system against secondary sodium leak of MONJU. The analytical results of floor temperature and hydrogen concentration were summarized in this report.In the sodium combustion analyses under the detailed design conditions, it was confirmed that the temperature rise of the floor liner was reduced In addition, as for the hydrogen concentration in sodium leak process which is formed by the reaction of sodium and moisture, it was confirmed that it is restricted under 4% of the hydrogen burn criterion. Concerning the hydrogen concentration due to the reaction with sodium and sodium hydroxide in the sodium pool after the storing, in the same way, it was confirmed that it is restricted under 4% of the criterion.
Nakai, Satoru; Kaneko, Yoshihisa; Uchihashi, Masaya
no journal, ,
Nakai, Satoru; Kaneko, Yoshihisa; Uchihashi, Masaya
no journal, ,
FBR can breed fuel and use minor actinide in the radioactive waste as a fuel, so that reduce environmental burden. Monju play a key role in the development of demonstration reactor in the aspects of demonstration of reliable operability and establishment of operation and maintenance method of FBR. In this paper describes the activities towards the establishment of Monju maintenance program and FBR maintenance method.
Nakai, Satoru; Nishio, Ryuichi; Uchihashi, Masaya; Kaneko, Yoshihisa; Yamashita, Hironobu*; Yamaguchi, Atsunori*; Aoki, Takayuki*
no journal, ,
A sodium cooled fast breeder reactor (FBR) has unique systems and components and different degradation mechanism from light water reactor (LWR) so that need to establish maintenance technology in accordance with its features. The examination of the FBR maintenance technology is carried out in the special committee for considering the maintenance for Monju established in the Japan Society of Maintenology (JSM). As a result of the study such as extraction of Monju maintenance feature, maintenance technology benchmark between Monju and LWR components and survey of LWR maintenance experience, it is clear that principles of maintenance are same as LWR, necessity of LWR maintenance experience reflection and points to be considered in Monju maintenance. The road map to establish a FBR maintenance technology in the technical aspect became clear and it is vital to acquire operation and maintenance experience of the plant to implement this road map, and to establish a fast reactor maintenance.
Kawabata, Mamoru; Sawa, Mamoru; Ono, Fumiyasu; Shimosaka, Mitsuo; Muto, Keitaro; Uchihashi, Masaya
no journal, ,
As a replacement for the analog camera system which has become difficult to repair, a digital transmission system using VDSL technology was devised by reusing idle facilities such as the voice communication network. This paper presents an overview of the remote monitoring system that can flexibly respond to the installation of additional cameras for other remote monitoring needs such as decommissioning work and equipment operation status checks that will increase in the future MONJU, as well as the transmission of measurement data from temporary instruments at a low cost.
Ono, Fumiyasu; Fukushima, Tsubasa; Naruse, Keiji; Matsui, Kazuaki; Obata, Ikuhito; Sawazaki, Hiromasa; Goto, Takehiro; Jo, Takahisa; Uchihashi, Masaya
no journal, ,
By storing fuel assemblies in the fuel pond in Phase 1, MONJU eliminates the residual risk of fuel assemblies remaining in the core, which holds chemically active liquid sodium, and from April 2023, Have moved to Phase 2 of decommissioning. As the decommissioning progresses, plant risks will continue to change. Therefore, we will organize the plant status at each Phase of decommissioning and formulate the concept of performance maintenance facilities for MONJU, which will be necessary in Phase 2, and Performance maintenance facilities were Reconsidered.
Fukushima, Tsubasa; Ono, Fumiyasu; Kuramoto, Shimpei; Nishino, Yuki; Nishino, Hajime; Uchihashi, Masaya
no journal, ,
"Monju" is a nuclear reactor facility that uses sodium to cool the reactor core. In order to reduce the risk of decommissioning, all liquid sodium in the cooling system piping was transferred to the tank and solidified in order to reduce the range of liquid sodium that may leak. Since this was the first attempt of this project, we dealt with issues such as the assessment of the impact on related equipment, the formulation of dedicated procedure manuals, and various operational changes, and streamlined equipment maintenance due to the reduction of the range of liquid sodium ownership, and summarized the results.