基于核数据的中子诱发原子离位损伤截面评估方法  

Evaluation Methods of Neutron-induced Atomic DisplacementDamage Cross Section Based on Nuclear Data

作　　者：陈胜利 袁岑溪 CHEN Shengli;YUAN Cenxi(Sino-French Institute of Nuclear Engineering and Technology,Sun Yat-sen University,Zhuhai 519082,Guangdong,China)

机构地区：[1]中山大学中法核工程与技术学院,广东珠海519082

出　　处：《原子核物理评论》2023年第2期303-313,共11页Nuclear Physics Review

基　　金：国家重点研发计划项目(2018YFB1900405);国家自然科学基金资助项目(12205390);广东省基础与应用基础研究重大项目(2021B0301030006,2019B030302011);广东省基础与应用基础研究基金项目(2023A1515010800);广东省科技计划国际科技合作项目(2019A050510022)。

摘　　要：中子辐照损伤是核能系统面临的重要挑战之一。中子辐照损伤是由中子核反应诱发的,通常通过离位损伤(用平均每原子离位数DPA计)量化。离位损伤的过程为中子核反应产生的反冲核,在辐照损伤中称为初级碰撞原子(Primary Knock-on Atom,PKA),引发材料中原子级联碰撞产生,因此其评估需要基于中子核反应理论或相关核数据。由于现有评价核数据库中未包含全部反冲能谱分布,中子辐照导致的离位损伤截面需要基于已有微分截面与守恒方程计算。本工作回顾了中子辐照诱发离位损伤的两种计算思路、系统地归纳了不同核反应类型(包括离散与连续的两体反应、中子俘获反应以及多体反应)导致的离位损伤截面计算理论方法、并指出了现有方法的不足。最后,以事故容错包壳材料FeCrAl为例,基于ENDF/B-Ⅷ.0数据库计算了多组不同Cr与Al含量的离位损伤截面。初步研究结果表明FeCrAl的中子辐照离位损伤评估对其中Cr与Al含量的敏感性较低且高出Fe单质的DPA截面约3%~4%,因此DPA评估中可暂不考虑不同Cr与Al含量的影响。但Cr与Al的含量可能会影响离位阈能与损伤能量。Neutron-induced irradiation damage is a major challenge for nuclear energy systems.Neutron irradiation damage is initiated by neutron-induced nuclear reactions and often quantified by the displacement damage,of which the conventional unit is the number of Displacements per Atom(DPA).Displacement damage is a consequence of atomic collision cascades in materials induced by recoil nuclei,which are referred to Primary Knock-on Atoms(PKAs)in radiation damage.Therefore,nuclear reaction data or nuclear reaction models are required to evaluate the neutron-induced displacement damage.Due to the lack of complete recoil spectra in the current evaluated nuclear data files,the calculation of displacement damage cross section(and thus the subsequent evaluation of irradiation damage level)should be based on the available differential cross sections and conservation laws.After the presentation of the two paths for evaluating neutron-induced displacement damage,the present work thoroughly summarizes the methods for computing displacement damage cross sections induced by different nuclear reaction types,including discrete and continuum binary reactions,neutron capture reaction,and the detailed discussion on many-body reactions.Then,the DPA cross sections of potential accident tolerant cladding material FeCrAl are calculated for various Cr and Al contents based on the recently evaluated ENDF/B-VIII.0 nuclear data library.Preliminary results show that the evaluation of neutron irradiation-induced DPA for FeCrAl is not sensitive to the content of Cr and Al,whereas the DPA in FeCrAl should be about 3%~4%higher than that in pure iron.The former conclusion implies that the evaluation of neutron irradiation-induced displacement damage can be performed with“arbitrary”contents of Cr and Al.However,it should be noted that the content of Cr and Al may influence the threshold displacement energies or the damage energy.

关 键 词：核数据 中子核反应 中子辐照损伤 DPA截面 FECRAL 

分 类 号：TL752.2[核科学技术—辐射防护及环境保护]