| Autor: |
Itoh, Ayumi, Inoue, Kosuke, Kobayashi, Yoshinao, Sakamoto, Kan, Endo, Yoichi, Nozaki, Kenichiro, Chai, Penghui, Suehiro, Shoichi, Honda, Takeshi, Owada, Kenji, Mizokami, Masato, Hirai, Mutsumi, Ito, Kenichi, Mizokami, Shinya |
| Zdroj: |
Journal of Nuclear Science & Technology; Nov2024, Vol. 61 Issue 11, p1453-1469, 17p |
| Abstrakt: |
The early phase of the core degradation at the Fukushima Daiichi Nuclear Power Station Unit 2 was investigated in terms of a fuel-component degradation by materials interaction by carrying out the accident analysis, evaluation of chemical conditions and experimental works. First, the accident scenario was evaluated to specify a target period (from 18:40 to 22:40 on NaN Invalid Date NaN), and then the temperature and H2/H2O pressure ratio in the core region during this period were calculated based on plant parameters. Subsequently, semi-integral experiments were performed using the mocked-up fuel components of a boiling water reactor (BWR). Furthermore, separate-effects tests using Ni-alloy/Zircaloy4 were also performed to understand the phenomenon observed in the semi-integral experiments, where the Ni-Zr reaction occurred even with the oxide layer on the Zr-based alloy. Consequently, it was estimated that the Zr-Ni eutectic melting reaction above 1100°C under steam-starved conditions resulted in a fuel failure at 19:08, melting of spacer locations at 19:37, and upper-tie-plate at 21:26. The first and second degradations could have caused the release of radioactive elements or particles leading to the neutron detection at 21:00 in front of the main gate, and the third degradation could have resulted in the separation of the upper-tie-plate. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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