[3L01-04] Fukushima NPPs Accident

[3L03] Fukushima Daiichi NPP Unit 2 Suppression Chamber Lower Part Leak Caused by Seismic Ground Motion

-Hypothesis examination and consequence-

*FUMIYA TANABE¹ (1. Sociotechnical Systems Safety Research Institute)

Keywords:Fukushima Daiichi NPP accident, Unit 2, suppression chamber, leak, seismic ground motion

The seismic ground motion on March 11^th, 2011 should have broken some pipe connected to the lower part of 1F2 S/C. The hypothesis is examined through detailed investigation into the S/C water level behavior until SBO. And then consequence is studied. Calculated result reveals that the S/C water level decreasing by the leak should have resulted in loss of safety functions such as RCIC on March 14^th due to uncovering of the pump suction line inlet.