中子辐照条件下的反常氚渗透机制研究

In order to realize the sustainable tritium cycle of fusion energy reactor, a large number of studies on tritium breeding module for fusion reactor have been carried out internationally. Tritium permeation is a crucial problem in the self-sustainable tritium cycle design. Excessive tritium permeation not only reduces the fuel cycle efficiency, but also accelerates the aging of structural materials. Experiments have confirmed that the abnormal phenomenon of significant increase in tritium permeation occurs under strong neutron irradiation, which can not be explained by the existing tritium permeation theory. In this project, recoil tritium is regarded as an important mechanism of anomalous tritium permeation. Based on the generalized semi-Markov process theory, a numerical simulation method of tritium permeation is developed to analyze the physical processes related to tritium permeation under neutron irradiation, and to study the behavior of tritium and helium-3 behind anomalous tritium permeation. The purpose of this study is to reveal the physical mechanism of abnormal tritium permeation under neutron irradiation, which is not only helpful for the research and design of tritium breeding module for fusion reactor, but also provides theoretical reference for the research and development of tritium permeation barrier under neutron irradiation.

为实现聚变能源堆的自身可持续氚循环，国际上开展了大量的聚变堆氚增殖模块研究，氚渗透是其中的关键问题，过高的氚渗透率既会降低燃料循环效率，又会加速结构材料的老化失效。实验已经证实，强中子辐照会引起氚渗透率出现显著增大的反常现象，现有的氚渗透理论无法对此做出合理的解释。本项目将反冲氚作为重要的反常氚渗透机制，基于广义半马尔科夫过程理论，发展氚渗透数值模拟方法，分析中子辐照条件下的氚渗透相关的物理过程，研究反常氚渗透现象背后的氚和氦-3行为规律。本研究力图揭示中子辐照条件下的反常氚渗透物理机制，既有助于聚变能源堆氚增殖模块的研究设计，又可为中子辐照条件下的防氚渗透涂层研发提供理论参考。

为实现聚变能源堆的自身可持续氚循环，国际上开展了大量的聚变堆氚增殖模块研究，氚渗透是其中的关键问题，过高的氚渗透率既会降低燃料循环效率，又会加速结构材料的老化失效。实验已经证实，强中子辐照会引起氚渗透率出现显著增大的反常现象。本项目在理论计算上构建了描述中子与氚相互作用模型，该模型耦合了热扩散、缺陷捕获/逃逸、衰变、核反冲/核反应等影响反常氚渗透的物理过程；采用弹性碰撞理论以及反冲氚能谱处理方式，将氚-中子的相互作用转化为高能氚的研究，同时基于对称性对涉氚材料模型进行了降维处理，实现了反常氚渗透模型的加速计算与快速收敛分析；以锆合金、UO2、低活化铁素体/马氏体钢为研究对象，提供了这三种材料中氚的反常渗透模拟结果；在实验上提供了锆合金、低活化铁素体/马氏体钢中氚的渗透率、扩散率等参数。本项目揭示了中子辐照环境下氚的反常渗透物理机制，提供了中子辐照条件下涉氚材料及部件的反常氚渗透数据。研究结果为快堆、聚变堆氚安全与防护提供了有效的理论参考。