2019 Fall Meeting

Presentation information

Oral presentation

III. Fission Energy Engineering » 304-1 Thermal Hydraulics, Energy Conversion, Energy Transfer, Energy Storage

[3F05-08] Fukushima Daiichi Accident

Fri. Sep 13, 2019 10:50 AM - 12:00 PM Room F (Common Education Bildg. 2F C21)

Chair:Chiaki Kino(IAE)

11:20 AM - 11:35 AM

[3F07] Inverse analysis of steam and hydrogen generation history of Fukushima Daiichi Nuclear Power Plant unit 3

*Shinji Yoshikawa1, Ikken Sato1 (1. Japan Atomic Energy Agency)

Keywords:FDNPP, leakage

Steam and hydrogen generation history and gas leakage area are inversely evaluated by a thermal hydraulic analysis code GOTHIC.

The analyzed period in the accident progression is from the arrival of reactor liquid level at the top of active fuel(TAF) until start of depressurization of reactor pressure vessel(RPV) by activation of automatic depressurization system(ADS). Based on the measured behaviors of the RPV and PCV pressures from 6:30 of March 13th until the ADS activation, some leakage from RPV to PCV is supposed during this period. The leakage path and area are inversely derived on plural possible accident scenarios. The leakage area are estimated to be no greater than 1 cm2.

This result suggests that the gas flow at the time of the main slumping would have been through S/C, where vapor condensation was effective, thus certain contribution of non-condensable gases like hydrogen seems necessary to explain the observed D/W pressure increase.