Study of Low Activation Materials for Fusion Reactor

为了获得聚变堆结构材料发展的基础数据，对Fe-Cr-Mn奥氏体钢、改性316不锈钢、铁素体钢和钒合金进行了中子、电子和/或离子辐照。并对与之相关的模型合金进行了辐照处理。实验结果表明：（1）改性后的316不锈钢具有较低的膨胀率，在30 dpa的低剂量下，其辐射活化程度较低。因此，改性后的316不锈钢可作为聚变反应材料使用较短的时间。(2)低活性Fe-Cr-Mn钢在500 ℃以上时相稳定性较低，因此，在200 ℃以下的较低温度下，可用作聚变堆结构件的支撑材料。(3)ITER后的DEMO将采用低活化Fe-（9-12）Cr基铁素体钢代替奥氏体钢，但仍存在一些问题需要解决，即嬗变过程中引入的氦导致的脆化。(4)钒合金具有良好的放射活化性能、抗辐照性能和高温强度，是未来聚变堆材料的发展方向。目前可推荐V-4Cr-Ti基合金，但这类合金对氧、氢等间隙杂质十分敏感。因此，如果将合金用作第一壁材料，则应避免杂质的影响。(5)随着合金的长期发展，还需要其他新的材料，如SiC和金属间化合物。

In order to obtain the fundamental data on the development of fusion reactor structural materials, Fe-Cr-Mn austenitic steel, modified 316 Stainless steels, ferritic steels and vanadium alloys were irradiated by neutrons, electrons and/or ions irradiations. Furtheremore the model alloys related these alloys were also irradiated. From these experimentals facts the following results and suggetion were obtained :(1) The modified 316 stainless steel showed lower swelling, and it is expected that these steels are lower radio-activated at lower dose of 30dpa. Therefore, the modified 316 stainless steels could be used as fusion react-or marerials for shorter periods.(2) Phase stability of low activated Fe-Cr-Mn steels was lower at temperature of above 500ﾟC.Therefore, when this type of steels are used for fusion reactor, it is aveirable as buck-up materials of structure components at lower temperature below 200ﾟC.(3) Instead of austenitic steels, the low activated Fe-(9-12)Cr based ferritic steels will be available for DEMO after ITER.However, there is still psome problems to be resolved, that is embrittlement due to helium introduced as a result of transmutation.(4) Future materials for fusion reactor, vanadium alloys are expected, because of the well characteristics of this alloy for radio-activation, the resistance against irradiation and high temperature strength. At present the alloy of V-4Cr-Ti based alloys can be recommended, but these alloys are very sensitive for interstitial impurities such as oxygen and hydrogen. Therefore, if the alloys will be used as first wall materials, the effect of the impurities should be avoided.(5) As the alloy development for long periods, other new matreials such as SiC and intermetallic coumpound will be needed.