Abstract

The CASL reactor simulation package VERA has been adapted to provide high-fidelity simulation capabilities for modeling source range detector response during subcritical reactor configurations. New features include the activation and shuffling of secondary-source assemblies, use of burned fuel neutron emission data from the ORIGEN depletion solver to the MPACT deterministic neutron transport solver, allowance of user-defined sources in MPACT based on material composition, ability to solve the subcritical source-driven system with neutron multiplication using the MPACT diffusion solver, and transfer of the calculated fission source from MPACT to the continuous-energy Monte Carlo solver Shift for final detector response evaluation using the CADIS methodology for variance reduction. These new capabilities were benchmarked against Watts Bar Unit 1 plant operating data for the first few fuel loading steps and were found to demonstrate excellent agreement with the measured data.

摘要

CASL反应堆仿真程序包VERA已调整为提供高保真模拟功能，用于在亚临界反应堆配置期间对源范围探测器的响应进行建模。新功能包括激活和改组二次源组件，使用从ORIGEN耗竭求解器到MPACT确定性中子输运求解器的燃烧后的燃料中子排放数据，基于材料成分的MPACT用户自定义源的允许，解决问题的能力次临界源驱动系统，使用MPACT扩散求解器进行中子倍增，并将计算出的裂变源从MPACT转移到连续能量蒙特卡洛求解器Shift，以使用CADIS方法进行最终检测器响应评估，以减少方差。