The Transient Multi-Level method for Monte Carlo reactor statics calculations

IF 1.9 3区工程技术 Q1 NUCLEAR SCIENCE & TECHNOLOGY

Annals of Nuclear Energy Pub Date : 2024-11-16 DOI:10.1016/j.anucene.2024.111021

Evan S. Gonzalez , Brian C. Kiedrowski , Gregory G. Davidson

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引用次数: 0

Abstract

The Transient Multi-Level (TML) method is applied to a time-dependent Monte Carlo transport solver to offload some of the computational burden of the expensive Monte Carlo solve to lower-order Coarse Mesh Finite Difference (CMFD) and Exact Point Kinetics Equations (EPKE) solvers via factorization of the neutron flux at the transport and CMFD levels using the Predictor Corrector Quasi-Static Method (PCQM). The Monte Carlo transient is solved by a modified fission source iteration scheme that introduces a single transient source bank. The method is implemented in the production-level Monte Carlo code, Shift, and verified with prescribed reactivity ramps from the two-dimensional version of the C5G7-TD reactor benchmark. The results show that, as compared to other quasi-static methods, the TML reduces the stochastic noise inherent to the transient Monte Carlo solver by factors of

\sim

2 to 6 for various norm comparisons of the reactor power amplitude. The TML additionally reduces the number of Monte Carlo evaluations needed to simulate the transient, leading to roughly an order of magnitude improvement in CPU time relative to the standard PCQM for the problems tested.

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用于蒙特卡罗反应堆静态计算的瞬态多级法

将瞬态多级（TML）方法应用于随时间变化的蒙特卡洛传输求解器，通过使用预测器校正器准静态方法（PCQM）对传输和蒙特卡洛传输级的中子通量进行因式分解，将昂贵的蒙特卡洛求解的部分计算负担卸载到低阶粗网格有限差分（CMFD）和精确点动力学方程（EPKE）求解器。蒙特卡洛瞬态求解采用修正的裂变源迭代方案，该方案引入了单个瞬态源库。该方法在生产级蒙特卡罗代码 Shift 中实施，并利用 C5G7-TD 反应堆基准二维版本的规定反应性斜坡进行了验证。结果表明，与其他准静态方法相比，对于反应堆功率幅值的各种规范比较，TML 可将瞬态蒙特卡罗求解器固有的随机噪声降低 2 至 6 倍。此外，TML 还减少了模拟瞬态所需的蒙特卡罗评估次数，与标准 PCQM 相比，在测试问题上的 CPU 时间大约提高了一个数量级。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Annals of Nuclear Energy 工程技术-核科学技术

CiteScore

4.30

自引率

21.10%

发文量

632

审稿时长

7.3 months

期刊介绍： Annals of Nuclear Energy provides an international medium for the communication of original research, ideas and developments in all areas of the field of nuclear energy science and technology. Its scope embraces nuclear fuel reserves, fuel cycles and cost, materials, processing, system and component technology (fission only), design and optimization, direct conversion of nuclear energy sources, environmental control, reactor physics, heat transfer and fluid dynamics, structural analysis, fuel management, future developments, nuclear fuel and safety, nuclear aerosol, neutron physics, computer technology (both software and hardware), risk assessment, radioactive waste disposal and reactor thermal hydraulics. Papers submitted to Annals need to demonstrate a clear link to nuclear power generation/nuclear engineering. Papers which deal with pure nuclear physics, pure health physics, imaging, or attenuation and shielding properties of concretes and various geological materials are not within the scope of the journal. Also, papers that deal with policy or economics are not within the scope of the journal.