In situ imaging of corrosion processes in nuclear fuel cladding
In situ imaging of corrosion processes in nuclear fuel cladding
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DOI：
10.1080/1478422x.2017.1344038
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发表时间：
2017-10
期刊：
影响因子：
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通讯作者：
A. Laferrere;R. Burrows;C. Glover;Ronald N. Clark;O. Payton;L. Picco;S. Moore;Geraint Williams
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文献类型：
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作者：
A. Laferrere;R. Burrows;C. Glover;Ronald N. Clark;O. Payton;L. Picco;S. Moore;Geraint Williams
英国的核废料储存在加入NaOH的池中，以抑制腐蚀，并且为了确保储存制度的效率，需要定义和量化在燃料包壳浸没期间涉及的腐蚀过程。在该项目中，采用最先进的表征技术对两种核燃料包壳材料（不锈钢和镁诺克斯）的腐蚀表面进行成像。先进气冷堆燃料包壳由20 Cr-25 Ni-Nb稳定化不锈钢组成，在辐照过程中，包壳的微观结构发生显著变化，包括晶界元素耗尽和偏析。具有纳米级分辨率的高速原子力显微镜能够对不锈钢中的沉淀物和凹坑形成进行成像。镁诺克斯是一种镁铝合金，在反应堆中辐照期间，外金属表面氧化，形成粘附的钝化层，随后在暴露于水时水合。腐蚀过程包括钝化和丝状腐蚀的击穿，这两者都是使用扫描振动电极技术在原位成像。
Spent nuclear fuel in the U.K. is stored within ponds dosed with NaOH in order to inhibit corrosion and, to ensure the efficiency of storage regimes, there is a need to define and quantify the corrosion processes involved during immersion of fuel cladding. In this project, state-of-the-art characterisation techniques were employed to image the corroding surfaces of two nuclear fuel cladding materials: stainless steel and Magnox. Advanced gas-cooled reactor fuel cladding consists of 20Cr-25Ni-Nb stabilised stainless steel and during irradiation the microstructure of the cladding undergoes significant changes, including grain boundary element depletion and segregation. High-speed atomic force microscopy with nanoscale resolution, enabled precipitates and pit initiation in stainless steel to be imaged. Magnox is a magnesium–aluminium alloy and during irradiation in a reactor the outer metal surface oxidises, forming an adherent passive layer which subsequently hydrates when exposed to water. Corrosion processes encompass breakdown of passivity and filiform-like corrosion, both of which were imaged in situ using the scanning vibrating electrode technique.