This paper proposed a method for the calculation of assembly bowing reactivity coefficients in sodium fast reactor. Firstly, in the core-analysis nodal method, a fuel assembly and a thin layer of sodium around it are treated as a node in the radial plane. Then the assembly bowing is discretized to radial displacements of the assembly region in each axial segment. Based on perturbation theory, the reactivity change caused by radial displacement can be expressed as the difference of reaction rates and leakage. The difference of total, scattering and fission reaction rates can be calculated by flux reconstruction and the corresponding cross sections. To take the leakage into account, this paper proposed a scheme to approximately evaluate the change of leakage by the gradient change of flux. Finally, the numerical results of the 2D and 3D problem show that this method achieves acceptable accuracy in these problems.

本文提出了一种钠快堆反应堆弯曲反应系数的计算方法。首先，在岩心分析节点法中，燃料组件和围绕它的钠薄层被视为径向平面中的节点。然后，将装配弓形离散化为每个轴向段中装配区域的径向位移。基于扰动理论，由径向位移引起的反应性变化可以表示为反应速率和泄漏的差。总通量，散射和裂变反应速率的差可以通过通量重建和相应的横截面来计算。考虑到泄漏，本文提出了一种通过通量梯度变化来近似评估泄漏变化的方案。最后，