Performance and verification test of FCVS for Kashiwazaki-Kariwa Nuclear Power Station Unit 6 and 7. (2) Measurement of decontamination factor for aerosol on steam condition

After the Fukushima Daiichi nuclear disaster, TEPCO launched a project to develop the Filtered Containment Venting System (FCVS), in which our very bitter experiences in the accident are reflected. One of the main purposes of the development of the FCVS is to enhance operability of venting under the severe plant conditions such as the SBO during progressing of severe core damage, and another is to enhance removal performance of radio-nuclides with the newly added filtering equipment, which is installed in the venting line from the PCV to the outer. The Kashiwazaki-Kariwa NPS unit 6 and 7 are the first reactors applied the FCVS. Performance of the FCVS has been verified by an extensive test program includes scaled filter venting test under various conditions. In this paper, we show some test results on aerosol decontamination factor (DF) under steam condition. The test results show that the DF under steam condition is higher than air condition. (author)