基于高效偶阶离散纵标法的全堆粒子输运模拟方法研究

The neutron physical calculation of reactor core plays an important role during both reactor design and reactor operation. High-precise reactor calculation can control safety allowance and optimize design, which improves the economy on the basis of ensuring safety. In traditional calculation, the two-step method based on diffusion theory has been widely used. With the increase of the heterogeneity of reactor core, the calculation accuracy of the diffusion theory faces significant challenges. Compared to the first-order transport equations, the even-parity transport theory decreases the storage and increases the efficiency vastly by solving only half of the angular domain. The discrete ordinates method is applied to even-parity equations and the conventional method is optimized and improved. A new high-efficiency even-parity SN method is proposed and applied to the whole-core transport calculation. It solves the bottleneck problem of SN method when applied to the whole-core transport engineering issue. Advanced acceleration method and large-scale parallel technology are introduced to improve the calculation efficiency. A high-precision and high-efficiency whole-core transport theory system is proposed and provides strong support for the high precision whole-core transport calculation.

核反应堆堆芯中子物理计算在反应堆设计和运行阶段都扮演着重要角色。高精度的堆芯计算能有效控制安全裕量、优化设计，在保证安全的基础上提升经济性，为反应堆安全运行提供重要支持等。基于扩散理论的两步法堆芯物理计算曾被广泛应用，但随着堆芯非均匀性的增强，计算精度受到巨大挑战。偶阶输运方程的求解相比一阶输运方程只需求解一半的角度空间，有效减小了计算存储、提升了计算效率。因此，本项目拟采用偶阶输运方程的离散纵标法思路，并在此基础上进行优化改进，开展高效偶阶离散纵标法HEPSn（High-efficiency Even-Parity Discrete Ordinates Method）的全堆粒子输运模拟方法研究，推动解决限制Sn方法全堆输运工程应用的瓶颈问题，探索先进加速方法和并行计算策略以提高计算效率，形成一套高精度、高效率的全堆粒子输运模拟方法体系，从而为高精度的全堆输运模拟计算提供有力支持。

核反应堆堆芯中子物理计算在反应堆设计和运行阶段都扮演着重要角色。基于扩散理论的两步法堆芯物理计算曾被广泛应用，但随着堆芯非均匀性的增强，计算精度受到巨大挑战，基于一阶输运方程的传统离散纵标方法又面临计算效率及存储的难题。本项目结合偶阶输运方程的离散纵标法及极角对称思想，研究建立高效偶阶离散纵标法HEPSN（High-efficiency Even-Parity Discrete Ordinates Method）的粒子输运模拟方法，在保证精度的前提下极大提高输运计算的效率，减小存储规模；实现了适用于大规模 HEPSN 输运方程的扩散综合加速技术；研究了基于区域分解的并行计算方法。在本项目的资助下，在国内外本领域杂志发表论文20篇，其中SCI收录11篇，EI收录6篇，中文核心期刊3篇。培养已毕业硕士研究生3 名，博士生1名，在读博士生2名，在读硕士生2名。本项目的研究有助于推动解决限制SN 全堆输运工程应用的技术瓶颈问题，提高大规模三维输运计算的效率，工程应用前景广阔。