Abstract A depletion solver has been implemented in OpenMC and is described herein. The depletion solver is implemented in Python and interfaces with OpenMC’s transport solver through a C++ application programming interface, which enables an in-memory transport-depletion coupling. Multiple integration methods for advancing in time have been implemented and exhibit tradeoffs in cost, accuracy, and memory use. For all time integration methods, evaluation of the matrix exponential is performed by using the incomplete partial fraction form of the Chebyshev rational approximation method. Simulations of a pressurized water reactor (PWR) pincell and a sodium-cooled fast reactor (SFR) assembly were carried out with OpenMC and Serpent. For both problems, the use of a high-fidelity depletion chain results in predictions of k eff that agree within 20–30 pcm between OpenMC and Serpent. Predicted actinide concentrations were found to agree to a fraction of a percent, and most fission product concentrations were found to agree within 1%. The few cases where larger differences were observed can be attributed either to differences in how the energy dependence of fission product yields is handled or deficiencies in the nuclear data used. OpenMC simulations of the PWR and SFR problems using a simplified 228-nuclide depletion chain demonstrate that it achieves accuracy close to that of the full, high-fidelity depletion chain with respect to the studied responses.

中文翻译：

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OpenMC Monte Carlo 粒子传输代码中的耗尽能力

摘要 耗尽求解器已在 OpenMC 中实现并在此进行描述。耗尽求解器在 Python 中实现，并通过 C++ 应用程序编程接口与 OpenMC 的传输求解器接口，从而实现内存中传输耗尽耦合。已经实施了多种用于及时推进的集成方法，并在成本、准确性和内存使用方面进行了权衡。对于所有时间积分方法，矩阵指数的评估是通过使用 Chebyshev 有理逼近方法的不完全部分分数形式进行的。使用 OpenMC 和 Serpent 对压水反应堆 (PWR) pincell 和钠冷快堆 (SFR) 组件进行了模拟。对于这两个问题，使用高保真耗尽链导致 OpenMC 和 Serpent 之间在 20-30 pcm 内一致的 k eff 预测。发现预测的锕系元素浓度与百分之几一致，并且发现大多数裂变产物浓度一致在 1% 以内。观察到较大差异的少数情况可归因于裂变产物产量的能量依赖性处理方式的差异或所用核数据的缺陷。使用简化的 228 核素耗尽链对 PWR 和 SFR 问题进行的 OpenMC 模拟表明，就所研究的响应而言，它实现的精度接近于完整、高保真耗尽链的精度。并且发现大多数裂变产物浓度都在 1% 以内。观察到较大差异的少数情况可归因于裂变产物产量的能量依赖性处理方式的差异或所用核数据的缺陷。使用简化的 228 核素耗尽链对 PWR 和 SFR 问题进行的 OpenMC 模拟表明，就所研究的响应而言，它实现的精度接近于完整、高保真耗尽链的精度。并且发现大多数裂变产物浓度都在 1% 以内。观察到较大差异的少数情况可归因于裂变产物产量的能量依赖性处理方式的差异或所用核数据的缺陷。使用简化的 228 核素耗尽链对 PWR 和 SFR 问题进行的 OpenMC 模拟表明，就所研究的响应而言，它实现的精度接近于完整、高保真耗尽链的精度。