No.6（2003）16.Recovery of collection efficiency of the used HEPA filter in radiation facilities

Noriyuki MIYAZAKI, Masayuki SEKIGUCHI, Noboru SAKURAI, Kazunari HOSOBUCHI, Kazuyuki MORI and Hidehisa SAEKI

Recovery of collection efficiency of the used high efficiency particulate air (HEPA) filter in the exhaust equipment was examined for its reuse. The used filter was treated with corona discharge and electric dust precipitation to remove dust accumulated on the used filter. Its collection efficiency was determined by the count of particles or that of RI (35S-cysteine) activity. Both particle and RI collection efficiencies of the used filter treated with dust removal were significantly higher than those of the used filter showing that this dust removal treatment is useful for recovery of collection efficiency of the used HEPA filter in radiation facilities. Electric charge treatment of particle or RI with corona discharge enhanced collection efficiency of the used or the new filter (particularly the used filter). This suggests that electric charge of dust is effective in enhancement of collection efficiency.

Keywords
HEPA filter, RI, Corona discharge, Collection efficiency, Electric charge

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