Solidification and re-melting mechanisms of SUS-B4C eutectic mixture
Solidification and re-melting mechanisms of SUS-B4C eutectic mixture
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DOI：
10.1016/j.jnucmat.2020.152527
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发表时间：
2021
影响因子：
3.1
通讯作者：
Takehiro Sumita;T. Kitagaki;M. Takano;A. Ikeda-Ohno
中科院分区：
文献类型：
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作者：
Takehiro Sumita;T. Kitagaki;M. Takano;A. Ikeda-Ohno
对不锈钢（SUS）和B4 C之间的高温相互作用的基本理解对于估算和表征沸水反应堆（BWR）严重事故（例如日本的福岛第一核电站（FDNPS，也称为“1F”））期间产生的燃料碎片是必不可少的。本研究的目的是系统地表征固化产物的熔融SUS-B4 C混合物的粉末X射线衍射（PXRD），扫描电子显微镜-能量色散X射线光谱（SEM-EDS），和热重-差热分析（TG-DTA）与范围内的B4 C含量相关的燃料碎片组合物预期在1F，以阐明凝固和重熔机制。结果表明，当B4 C含量低于3mass%时，γ-Fe和（Cr，Fe）2 B是主要的凝固相;当B4 C含量超过3mass%时，（Cr，Fe）23（C，B）6作为附加的第三相形成。SUS-B4 C混合物的凝固和凝固后的重熔均为共晶，主要受Fe-B伪二元系控制，并受C、Cr含量和Mo等微量元素的影响。
Fundamental understanding of the high-temperature interaction between stainless steel (SUS) and B4C is indispensable for estimating and characterizing the fuel debris generated during severe accidents of boiling water reactors (BWR), such as Fukushima Dai-ichi Nuclear Power Station (FDNPS, also referred to as “1F”) in Japan. This study aims at systematically characterizing the solidified products of molten SUS-B4C mixtures by powder X-ray diffraction (PXRD), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), and thermogravimetry-differential thermal analysis (TG-DTA) with a range of the B4C content relevant to the fuel debris composition expected at 1F, in order to elucidate the solidification and re-melting mechanisms. The results indicated that γ-Fe and (Cr,Fe)2B are the major solidified phases when the B4C content is below 3 mass%, while (Cr,Fe)23(C,B)6is formed as an additional third phase when the B4C content exceeds 3 mass%. The solidification of molten SUS-B4C mixture and re-melting of solidified SUS-B4C melt are eutectic, which is mainly controlled by the pseudo-binary Fe–B system that is influenced by the C and Cr content and additional minor components such as Mo.