Performance and Verification Test of Filtered Containment Venting System for Kashiwazaki-Kariwa NPP Unit 6 and 7

(3) Measurement of Decontamination Factor for Iodine Gas on Air Condition

Abstract

After the Fukushima Daiichi nuclear disaster, Tokyo Electric Power Company (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 Kasshiwazaki-Kariwa NPS unit 6 and 7 are the first reactors applied the FCVSs. Performance of the FCVS has been verified by an extensive test program which includes scaled filter venting test under various conditions. In this paper we show schematic of our test facility and some test results on Iodine gas decontamination factor (DF). The test results clearly show that the DF of the system is above the FCVS design target value (DF>1000).