Replacement of the criticality accident alarm system in the Tokai Reprocessing Plant

Sanada, Yukihisa; Ishii, Masato*; Hasegawa, Ichiro; Kanazawa, Nobuyuki; Chikazawa, Tatsuya*; Momose, Takumaro

NEA/CSNI/R(2010)4 (Internet), p.351 - 370, 2010/11

https://www.oecd-nea.org/nsd/docs/2010/csni-r2010-4.pdf

A criticality accident alarm system (CAAS) was installed in the 1980s as part of criticality safety management at the Tokai Reprocessing Plant (TRP) to reduce the chance of workers being exposed to radiation in the rare case of a criticality accident. From a compliance point of view processing at TRP cannot take place without the criticality monitoring provided by the CAAS. This paper gives an overview of the process of the CAAS being replaced as part of aging management.

Performance tests of a melting system for miscellaneous solid wastes and corrosion tests of a long-life refractory material (Contract research)

Isobe, Motoyasu; Kameo, Yutaka; Nakashio, Nobuyuki; Wakui, Takuji*; Iwata, Keiji*; Kibayashi, Tatsuyuki*; Kanazawa, Katsuo; Nakashima, Mikio; Hirabayashi, Takakuni*

JAERI-Tech 2000-049, 29 Pages, 2000/09

JAERI-Tech-2000-049.pdf:2.87MB

no abstracts in English

Development of the improved criticality accident alarm system that achieves high reliability

Kanazawa, Nobuyuki; Sanada, Yukihisa; Suzuki, Hideki; Endo, Kuniaki; Ishii, Masato*; Hasegawa, Ichiro

no journal, , 

A Criticality Accident Alarm System (CAAS) was installed as part of criticality safety management for use in reducing the radiation workers could be exposed to in the rare case of a criticality accident. The initial CAAS version was installed to the Tokai Reprocessing Plant (TRP) in the 1980s. In this study, the new CAAS was developed for replacement at the Plutonium conversion development facility (PCDF).

Treatment test of decontamination wastes using a pilot-scale pyrolysis furnace, 1; Outline of test and furnace

Kanazawa, Shingo; Osugi, Takeshi; Nakashio, Nobuyuki; Ishihara, Keisuke; Yokobori, Tomohiko; Okoshi, Minoru; Tokizawa, Takayuki; Nakayama, Shinichi; Kimura, Takeshi*

no journal, , 

no abstracts in English

Effective dealing with aging alpha dust monitors

Imahashi, Atsushi; Sagawa, Naoki; Kanazawa, Nobuyuki*; Tamura, Toshinobu*; Hosomi, Kenji; Takashima, Hideki

no journal, , 

Alpha dust monitors are used for continuous measurering of airborne alpha contamination in radiation control area in NCL JAEA. In case of emergency, alarm is issued to evacuate workers. However, number of false alarms due to degradation of equipment are increasing year by year, because the equipment has been used more than 30 years. Now, we are updating our old silicon detectors to new ion-implanted silicon detectors with high endurance. We are also installing new preamplifier cercuits which is strong against electrical noise. As a result, reliability of alpha dust monitors has been ensured. In this talk, a report about our effective deal with the aging equipment will be given.