Comparative molecular simulation studies of oxidation reactions and hydrogen release for zirconium metals and silicon carbide under severe accident conditions

Masahiko Machida, Hiroki Nakamura, S. G. Srinivasan, Adri C.T. Van Duin

Research output: Contribution to conferencePaper

Abstract

Zircalloy has been widely employed as an excellent material covering the fuel rod. The mechanical and thermal properties have been explored by various experiments [1]. In terms of its use as the fuel cladding, its response to oxidation reactions is an important topic when it is exposed to high temperature and high pressure steam during severe accidents. Especially, the hydrogen production accompanied by the oxidation is critical because it can lead to the crisis of the hydrogen explosion, as observed in the Fukushima nuclear power plant accidents. Silicon carbide (SiC) has been considered as an alternative cladding material owing to an advantage that hydrogen production is much suppressed in the equivalent condition compared to Zircalloy. Therefore, we simulate the oxidation reaction for both materials, i.e. Zirconium metal and SiC in atomistic level by using the ReaxFF reactive force field method to simulate the chemical reaction molecular dynamics. Through such comparative studies between Zirconium and SiC in the same condition, we clarify how the temperature and the steam pressure accelerates the oxidation reaction and the resultant hydrogen production in both materials at typical severe accident conditions. The advantage using ReaxFF is that it allows us to directly trace the oxygen diffusion inside the Zirconium metal and SiC depending on the temperature and vapor pressure together with the oxidation reaction. We can compare the reaction processes in both materials. Especially, we paid attention to the rate of hydrogen production in both materials.

Original languageEnglish (US)
StatePublished - Jan 1 2015
Event23rd International Conference on Nuclear Engineering: Nuclear Power - Reliable Global Energy, ICONE 2015 - Chiba, Japan
Duration: May 17 2015May 21 2015

Other

Other23rd International Conference on Nuclear Engineering: Nuclear Power - Reliable Global Energy, ICONE 2015
CountryJapan
CityChiba
Period5/17/155/21/15

All Science Journal Classification (ASJC) codes

  • Nuclear Energy and Engineering

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    Machida, M., Nakamura, H., Srinivasan, S. G., & Van Duin, A. C. T. (2015). Comparative molecular simulation studies of oxidation reactions and hydrogen release for zirconium metals and silicon carbide under severe accident conditions. Paper presented at 23rd International Conference on Nuclear Engineering: Nuclear Power - Reliable Global Energy, ICONE 2015, Chiba, Japan.