压水堆棒状燃料氧化与吸氢模型开发及验证

Development and validation of models for fuel rod oxidation and hydrogen pick-up behaviors in pressurized water reactor

核反应堆长期运行过程中,锆合金包壳与冷却水接触会发生氧化反应、吸氢脆化行为,使包壳的导热性能和力学性能恶化,威胁燃料元件的安全特性。因此,开展棒状燃料氧化与吸氢行为研究具有重要意义。本文实现了MOOSE-BEEs燃料性能分析程序中压水堆棒状燃料堆内腐蚀计算模型的开发,主要包括氧化腐蚀模型和吸氢腐蚀模型。基于相关的实验数据和BISON程序计算结果,对氧化腐蚀、氢扩散、氢析出等单个模型及耦合模型开展了验证。验证结果表明BEEs的模拟结果与实验数据和BISON程序吻合较好,说明BEEs能够准确模拟燃料棒的氧化与吸氢行为。

[Background]During the long-term operation of a nuclear reactor,the contact between zirconium alloy cladding and cooling water results in oxidation reactions and hydrogen uptake-induced embrittlement behavior,which deteriorates the thermal and mechanical properties of the cladding,posing a threat to the safety characteristics of fuel elements.Therefore,conducting research on the oxidation and hydrogen uptake behavior of rod-shaped fuels is of significant importance.MOOSE is an object-oriented finite element multi-physics coupling platform developed using the C++programming language.BEEs,developed based on MOOSE,is programmed in C++and operates under the Linux system.[Purpose]This study aims to integrate a corrosion model into MOOSE-BEEs fuel performance code and verify its adaptability,consisting of an oxidation corrosion model and a hydrogen absorption corrosion model.[Methods]Firstly,a corrosion calculation model for pressurized water reactor rod-shaped fuel in the MOOSE-BEEs program was developed and integrated into the MOOSE platform to enhance the functionality of the BEEs program.The corrosion model primarily included an oxidation corrosion model and a hydrogen absorption corrosion model.The oxidation model served as the boundary of the hydrogen absorption model to provide hydrogen uptake.The hydrogen at the boundary diffused under the action of concentration gradient and temperature gradient.Then,according to the relationship between the concentration in the region and the terminal solid solubility,predictions was made regarding the occurrence of precipitation phenomena at this location.The terminal solid solubility and precipitation rate are related to temperature.Subsequently,simple geometric structures were established to perform coupled calculations of fuel thermal conductivity,oxidation,hydrogen absorption corrosion,hydrogen diffusion and precipitation.Finally,the calculated results were compared with the BISON program and experimental values,and the hydrogen precipitation was verified in terms of terminal solid solubility and precipitation rate.[Results]Based on experimental data and computational results from the BISON program,separate models and coupled models for oxidation corrosion,hydrogen diffusion and hydrogen precipitation have been validated.The oxidation corrosion model is in good agreement with REP Na10 experiment results and Katheren calculation results.Hydrogen diffusion verification includes concentration gradient verification and temperature gradient verification.The diffusion model and hydrogen precipitation model are in good agreement with the results of BISON simulation and Kammenzind experiment.The coupling model of oxidation and hydrogen absorption corrosion is in good agreement with the results of BISON simulation and Gravelines reactor experiment.The difference between the calculated results of most corrosion models and the experimental values and BISON program is less than 10%.[Conclusions]The validation results demonstrate that the BEEs predictions are in good agreement with the experimental data and BISON program,indicating that BEEs is capable of accurately simulating the oxidation and hydrogen absorption behavior of fuel rods.