Hydrogen combustion management during a severe accident at the plant with the ice condenser type containment

In Japan, hydrogen mitigation measures inside the containment vessel during a severe accident are taken against the plant with the ice condenser type containment. Ohi Power Station Unit No.1 and 2, which Kansai Electric Power Co.,Inc. owns, are the only plants of this kind in Japan. Kansai has investigated the hydrogen mitigation measures in collaboration with Mitsubishi Heavy Industry Co.,Ltd. As a result of extensive experiments and analyses, the glow plug type igniter was selected as a hydrogen mitigation device. Environmental conditions were investigated for the purpose of selection of the device. To decide the location of installation, Kansai performed analysis of mixing behavior of hydrogen focusing on the results of small scale combustion testing conducted by Nupec (Nuclear Power Engineering Corporation). This paper will introduce the detailed results of Kansai's investigation of hydrogen mitigation measures for Ohi Power Station Unit No.1 and 2. (author)