The neutron irradiation-induced mechanical property change is a major challenge for nuclear materials. For a Pressurized Water Reactor (PWR), neutron irradiation embrittlement of the reactor pressure vessel is one of the most important issues that determine the whole nuclear power plant lifetime. The present work focuses thus on the uncertainty assessment for the neutron irradiation displacement damage of a PWR vessel. The uncertainties of neutron flux, nuclear data, and atomic displacement models are propagated to Displacement per Atom (DPA) rates with a special emphasis on the importance of correlation matrices. In addition to the uncertainty propagated from the threshold displacement energy, the total uncertainty of damage energy rate is about 10% (at 1σ), whereas the uncertainty is largely underestimated if the correlations of damage cross section and neutron flux are not considered. Apart from the complete uncertainty propagation shown in this paper, combining the damage energy rate uncertainty and the displacement threshold energy uncertainty is recommended for estimating the calculated DPA rate uncertainty. Besides the uncertainty, the biases induced by the model defects are preliminarily estimated.

中子辐照引起的机械性能变化是核材料面临的主要挑战。对于压水堆（PWR）而言，反应堆压力容器的中子辐照脆化是决定整个核电站寿命的最重要问题之一。因此，目前的工作重点是对压水堆容器中子辐照位移损伤的不确定性评估。中子通量、核数据和原子位移模型的不确定性被传播到每原子位移 (DPA) 率，并特别强调了相关矩阵的重要性。除了从阈值位移能量传播的不确定性外，损伤能量率的总不确定性约为 10%（在 1 σ)，而如果不考虑损伤截面和中子通量的相关性，则很大程度上低估了不确定性。除了本文所示的完全不确定性传播外，建议结合损伤能量率不确定性和位移阈值能量不确定性来估计计算的 DPA 率不确定性。除了不确定性之外，还初步估计了模型缺陷引起的偏差。