[2K06-07] Fukushima Daiichi Nuclear Power Plant Accident

[2K07] Temperature change due to radiative cooling under the fuel rod exposure in Fuku-Ichi No.1 Reactor

Recursive calculation of temperature using a simplified 3-D model(1)

*Kiyoshi Yoneyama¹, Yuji Horie, Kazuo Watanabe² (1. H.O.Yoneyama, 2. WNR-Cx Watanabe Lab)

Keywords:Fuku-Ichi No.1 Reactor, Radiative cooling (heat transfer), Numerical analysis, Zirconium oxidative reaction

The No.1 reactor of Fuku-Ichi experienced a hydrogen gas explosion on 3/12/2011, resulting in a severe nuclear catastrophe. It was due to the same cause as No. 3 reactor, in which hydrogen gas was produced from zirconium cover of the fuel rod by oxidation reaction. However, the time of gas production remains uncertain because of the absence of temperature calculation on the reactor core. The authors set up a simple model approximating the fuel core by 10 consecutive spherical shells. A numerical analysis of radiative heat transfer under the condition of decay heat 1% indicated that the core temperature reached in 35 minutes 1500 Celsius, which is high enough to trigger oxidation reaction of zirconium.