氢同位素在辐照损伤低活化钢中渗透滞留行为的实验和模拟研究

Reduced activation ferritic/martensitic (RAFM) steel is considered to be the first choice of the structural material of ITER and future fusion blanket. The permeation and retention behavior of fuel tritium (T) in fusion reactor materials is vital for the economy and safety of the reactor. The high fluence radiation of 14MeV fusion neutrons will produce various kinds of defects in material with centimeter scale thickness, these irradiation defects will definitely influence the behavior of D/T permeation and retention in materials. So far, this issue has not yet been investigated systematically, due to both the extreme lack of 14MeV neutron sources and the activation of the neutron irradiated samples. In this project, high energy heavy ion beams from the HIRFL-SFC line and high-energy electron beams will be used to produce quasi-uniformly distributed irradiation defects in RAFM steels and get samples with different defects types and damage in different level. Gas-driven permeation and thermal desorption spectroscopy experiments are performed to study the effect of permeation and retention of hydrogen isotopes inirradiated RAFM steel sample. A series of multi-scale simulation methods are applied to analyze experimental results, explain the interaction mechanism of hydrogen isotopes with defects, and simulate the permeation and retention behavior of the hydrogen isotope in irradiated materials. This project will provide direct support for the R&D acitvities towards new grades of materials involving with tritium, which will surely contributes significantly to the development of fusion undertaking in China.

低活化铁素体/马氏体钢被认为是ITER和未来聚变堆包层首选结构材料。聚变堆燃料氚在聚变堆材料中的渗透与滞留行为直接关系到未来聚变堆运行的经济性与安全性。聚变堆高通量的14MeV中子辐照将在厘米厚度的材料中产生各种缺陷积累，这些辐照缺陷将会严重影响到氢同位素在材料中的渗透和滞留行为。由于14MeV中子源极度缺乏以及中子辐照样品活化的原因，这些问题到目前为止尚缺乏系统研究。本项目拟利用HIRFL-SFC高能重离子辐照端口、高能电子辐照装置，在低活化钢中引入宏观尺度均匀分布的辐照缺陷，制备不同缺陷类型和损伤程度的辐照样品；通过气相渗透-热脱附谱联合实验平台，研究辐照缺陷对低活化钢中氢同位素渗透和滞留行为的影响；结合一系列多尺度模拟手段，分析实验结果、解释缺陷与氢同位素相互作用机理，并模拟氢同位素在辐照损伤材料中的渗透滞留行为。为聚变堆涉氚材料的研发提供直接支持，为我国的聚变事业的发展做出贡献。

低活化铁素体/马氏体钢被认为是ITER和未来聚变堆包层首选结构材料。聚变堆燃料氚在聚变堆材料中的渗透与滞留行为直接关系到未来聚变堆运行的经济性与安全性。聚变堆高通量的14MeV中子辐照将在厘米厚度的材料中产生各种缺陷积累，这些辐照缺陷将会严重影响到氢同位素在材料中的渗透和滞留行为。由于14MeV中子源极度缺乏以及中子辐照样品活化的原因，这些问题到目前为止尚缺乏系统研究。本项目开展了多种低活化钢辐照样品的制备工作，主要借助北京大学的4.5MV静电加速器进行氦离子辐照实验、辅助其他氘等离子体辐照手段。系统研究了辐照缺陷对氢同位素在CLF-1钢、HUST4钢和Fe-Cr-Al铁素体钢样品中的渗透滞留行为。针对辐照缺陷对氢扩散系数的影响机理，模拟了各种辐照缺陷与氢的相互作用，获得了氢的结合能和扩散能垒，以及缺陷对H在Fe中扩散系数的影响。相关结果可以为ITER及CFETR氚输运分析提供基础数据，为聚变堆涉氚材料的研发提供直接支持，为我国的聚变事业的发展做出贡献。