Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Fukuchi, Taira; Sanyoshi, Hirotaka; Yatogi, Hideo; Fukuari, Yoshihiro; Inami, Shinichi
Dai-7-Kai Saishori, Risaikuru Bukai Semina Tekisuto, p.170 - 171, 2011/01
no abstracts in English
Takeuchi, Kenji; Sanyoshi, Hirotaka; Fukuari, Yoshihiro; Inami, Shinichi
Proceedings of 7th International Conference on NDE in relation to Structural Integrity for Nuclear and Pressurized Components (CD-ROM), p.37 - 44, 2010/00
In the Tokai Reprocessing Plant (TRP), lots of blowers are used for enclosing radioactive materials in a controlled area, and pumps are used for circulating cooling water to keep temperature under appropriate conditions of vessels, which contain high-level radioactive liquid waste. These rotating equipments play an important role in safety management of the nuclear facilities, where they are required stable conditions all the time. To improve the reliability of rotating equipments, the condition based maintenance for detecting the deterioration is one of the effective measures. According to the analyses of the past maintenance data obtained in TRP, it has been found that about 90% troubles related to the rotating equipment are caused in the bearing works, in which the lubrication was defective in almost every case. So, it is very important for stable operation of the rotating equipment to monitor the lubrication conditions in bearings. The vibration method facilitates to detect defects and abrasion of bearings by measuring a vibration signal. However, this method has a disadvantage that quantitative management for the lubrication conditions of bearings is not possible. Therefore, the shock pulse method, which is widely used for diagnosis of the bearings, is applied to assess the deterioration of rolling bearing. The shock pulse method can detect the change of the lubrication condition and the presence of defects in bearings, by a pressure wave generated from rotating rolling bearing. The method can also evaluate the oil slick thickness and the condition of deterioration in the bearing. As one of maintenance activities performed after monitoring, replenishment with a suitable amount of oil for a lubricant was able to be conducted with a proper timing. As a result, the number of the troubles on bearings has significantly reduced because proper maintenance for keeping the oil slick thickness can be carried out, which resulted in stable operation of the rotary equipmen
Terunuma, Tomohiro; Ozeki, Tatsuya; Fukuari, Yoshihiro
Nihon Hozen Gakkai Dai-5-Kai Gakujutsu Koenkai Yoshishu, p.129 - 132, 2008/07
The two dissolvers installed in the Tokai reprocessing plant had failed occurred successively in 1982 and 1983. Then, remote-controlled equipment for repair and inspection has been developed because the dissolvers were installed under the high dose of radiation and cannot access easily. After repair of the dissolvers, the periodic inspection by remoteness is periodically carried out once per year for soundness confirmation of the vessels. Moreover, the remote inspection equipment for periodic inspection was developed, which time required for inspection is too short compared with former equipment.
Yasuo, Kiyoshi; Seto, Nobuhiko; Watahiki, Seiichi; Fukuari, Yoshihiro
Nihon Hozen Gakkai Dai-5-Kai Gakujutsu Koenkai Yoshishu, p.385 - 387, 2008/07
The nitric acid solution including nuclear fuel material is transferred by the three way valve called VCV (VCV: vide-casse-vide in Fr.) using vacuum in the Tokai Reprocessing Plant. The reliability of initial three way valve was not obtained because failure occurred by use for one or two years. The cause of failure was damage of the plastic diaphragms in the moving parts. Then, the new three way valve with stainless-steel bellows was developed. there is no failure in moving parts, reliability improved significantly.
Domura, Kazuyuki; Sanyoshi, Hirotaka; Fukuari, Yoshihiro; Inami, Shinichi
no journal, ,
no abstracts in English
Kawasumi, Hiroyuki; Sanyoshi, Hirotaka; Yatogi, Hideo; Fukuari, Yoshihiro; Inami, Shinichi
no journal, ,
In the ventilation facilities of the Tokai reprocessing plant, particle filters are generally installed both in air-intake and exhaust systems. In the air-intake system, atmospheric dust is filtered and the cleaned air is supplied into radiation controlled areas, whereas in the exhaust system, radioactive materials are filtered and discharge it to the environment. Because the filter of the exhaust system serves to prevent radiological release to the environment, a high-efficiency particle air (HEPA) filter that a decontamination factor is extremely high, is used for filtering radioactive particles. The HEPA filter is usually exchanged with new one when the filter is carried over with particles, or it is exchanged by the limit as an anti-aging deterioration measure in time. This report reviews the exchange period of a periodical filter by confirming the integrity of a filter installed in investigation and the enforcement of the past filter exchange results and reports the result that planned adequacy.
Domura, Kazuyuki; Morimoto, Kenji; Seto, Nobuhiko; Iwasaki, Shogo; Fukuari, Yoshihiro; Inami, Shinichi
no journal, ,
A leak occurred from the sea release pipe buried in the bottom of the sea of the Tokai reprocessing plant. The plumbing of the leak point was cut to investigate the cause of the leak and was collected ashore. Then the investigations such as surface observation and other analyses were performed. As a result of this investigation, the plumbing was scratched at the time of construction from the outside. In the service of approximately 17 years, a damaged part changed with age, and it was estimated that it led to a crack. It was estimated for the leak of the plumbing that hydrogen produced with electrolytic protection caused hydrogen embrittlement cracking and hydrogen induced cracking. This paper reports the details of the investigations.