基于PBR的核电金属材料腐蚀释放模型研究

Research on corrosion release model for nuclear metallic materials based on PBR

核电金属材料在高温高压水环境中发生腐蚀,其腐蚀产物将会在堆芯内沉积,并对燃料运行、堆芯反应性及一回路放射性等产生影响。本文基于腐蚀释放动力学理论,结合金属氧化物体积比(Pilling-Bedworth Ratio,PBR)假设,建立了一种核电金属材料腐蚀释放模型,并基于因科镍690的实验数据,对该模型进行了验证。结果表明:该腐蚀释放模型具有科学性及合理性,可定量分析核电金属材料主要的腐蚀释放产物。本文提出的腐蚀释放模型可量化腐蚀产物主要元素,为反应堆腐蚀产物影响分析提供基础要素,对微量元素的量化后续还需做进一步的研究。

[Background]The metallic materials utilized for nuclear reactors undergo corosion due to the inherient high-temperature and high-pressure environment.Consequently,the corrosion products may be deposited in the core,called crud,and impact the fuel operation,core reactivity,and primary radioactivity,such as crud-induced localized corrosion or crud-induced power shift.[Purpose]Thus,this study aimed to establish a model that can quantitatively analyze these corrosion products,the results of which can then be used to evaluate the impact of these products.[Methods]Based on the corrosion and release dynamic theory,combined with the assumption of metallic oxide volume ratio(Pilling-Bedworth Ratio),a corrosion and release model of metallic materials was developed.The model was validated based on experimental data from Inconel 690.[Results]The verification result indicates that the proposed model is reasonable and scientific,and hence can be used to quantify the amount of main corrosion and release products of metallic materials for nuclear reactors.[Conclusions]This study provides a model of the main elements of corrosion products including Ni and Fe ferrite for PWR plants,which can be used for evaluating the impact of corrosion products.However,some of the microelements of corrosion cannot be quantified by using this model as the corresponding equations were over-determined.Hence this aspect requires further research in the future.