New air cleaning technology in Japan

Application of the new techniques and improvements in air cleaning systems have been made to reduce release of radioactive materials from nuclear facilities based on the ALARA concept. For example, the reduction of release of radioactive gaseous effluents has been made by installation of a charcoal gas hold-up system and a clean steam supply system for a turbine gland seal in a BWR and of a gas decay tank system in a PWR. In connection with the effort for reduction of releases in plants, research and development on air cleaning technology have also been made. Some activities mentioned in the present paper are: removal of particulates, airborne radioiodine, noble gases and tritium; penetration characteristics of submicron DOP aerosol for HEPA filters; radioiodine removal from air exhausts; and operational performance of the incineration plants using ceramic filters