Optimization of the exchange period of high efficiency particulate air filter in Tokai Reprocessing Plant

Kawasumi, Hiroyuki; Sanyoshi, Hirotaka; Yatogi, Hideo; Fukuari, Yoshihiro; Inami, Shinichi

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.