一种结合物理模型与数据驱动方法的氙振荡代理模型

A Hybrid Physics-informed Surrogate Model Approach for Xenon-induced Power Oscillation in Nuclear Reactor

  • 摘要: 针对现有氙振荡预测方法存在模型适用性局限、计算成本高及数据依赖性强等问题,本文提出一种融合物理模型与数据驱动的代理模型,旨在基于少量的Bamboo-C程序计算结果,实现不同功率瞬变工况下氙振荡演化规律的高效预测。模型基于核反应堆两群一维扩散模型及氙-碘动力学方程,构建轴向功率形状指数(ASI)的简化物理模型,使用DE-SLSQP混合算法结合若干工况的Bamboo-C程序计算结果对简化物理模型的关键参数进行搜索,最终获得一套可用于氙振荡预测的代理模型。结果表明:代理模型对于不同初始功率水平的工况均具备良好的泛用性。模型在初始功率40%FP~100%FP工况下,预测曲线与参考曲线的ASI最大相对差值小于0.1,均方误差(MSE)低于10−4;功率瞬变(ΔP)与关键参数的线性及指数拟合决定系数(R2)达到0.99以上,且对大功率瞬变工况(ΔP≥60)预测精度较高。本文模型显著降低了氙振荡预测的计算复杂度,具有简化堆芯功率能力分析计算量的潜力,但其对小功率瞬变工况的适应性及控制棒扰动下的拓展仍需进一步优化。

     

    Abstract: The prediction of xenon-induced power oscillations in nuclear reactors is crucial for operational safety and efficiency. However, existing methodologies are often constrained by limitations in model applicability across diverse conditions, high computational costs associated with high-fidelity codes, or a heavy reliance on extensive datasets for purely data-driven models. This study presents the development and validation of a surrogate model designed to mitigate these challenges. The model integrates a physics-informed structure with a data-driven parameterization to enable efficient and accurate prediction of xenon-induced power oscillation dynamics under various power transients, utilizing a limited number of reference simulations from the Bamboo-C code. The methodological framework was established upon a simplified physical model for the axial shape index (ASI), which was derived from the one-dimensional, two-group neutron diffusion theory and the associated xenon-iodine dynamics equations. To parameterize this model, a hybrid optimization algorithm, which combined the global search capabilities of the differential evolution (DE) algorithm with the local convergence efficiency of the sequential least squares programming (SLSQP) method, was implemented. This algorithm identified the key unknown parameters of the model by assimilating a small set of reference ASI transient data, which was generated by Bamboo-C for five training scenarios originating from a 100%FP (full power) initial condition. Following the parameter identification, functional relationships between the key model parameters and the magnitude of the power transient (ΔP) were established via regression analysis. The analysis shows that these relationships can be accurately characterized by simple linear and exponential functions, with all corresponding coefficients of determination (R2) exceeding 0.99. This enables the surrogate model to calculate the necessary parameters for new, unsimulated transient scenarios by using ΔP as the sole input. The model’s predictive performance and generalization capability were subsequently evaluated across a comprehensive range of operating conditions, with initial power levels from 100%FP down to 40%FP. The validation results indicate that the surrogate model can effectively reproduce the reference ASI dynamics. For transients originating from 40%FP to 100%FP, the maximum relative difference between the predicted and reference ASI curves is maintained below 0.1, and the mean squared error (MSE) is below 10−4. The model demonstrates higher predictive accuracy for scenarios involving large-magnitude power transients (e.g., ΔP≥60), where the oscillation characteristics are more distinct. While the proposed framework substantially reduces the computational burden of xenon-induced power oscillation analysis, its performance for small-magnitude transients indicates an area for further refinement. Future work will be directed toward improving the model’s accuracy in these specific regimes and extending its scope to include the effects of control rod perturbations.

     

/

返回文章
返回