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，用中子、电子和离子对Fe-Cr-Mn奥氏体钢、变质316不锈钢、铁素体钢和钒合金进行了辐照。此外，还对与这些合金相关的模型合金进行了辐照。根据这些实验事实，得到了以下结果和建议：(1)改性316不锈钢表现出较低的膨胀率，预计这些钢在较低剂量30dpa时具有较低的放射性活化度。(2)低活性Fe-Cr-Mn钢在500ﾟC以上时相稳定性较低。因此，当用于聚变反应堆时，在200ﾟC以下可作为结构部件的增压材料。(3)低活性Fe-(9-12)Cr基铁素体钢可替代奥氏体钢用于ITER后的演示。由于钒合金具有良好的辐射激活特性、耐辐照性能和高温强度，因此有望成为聚变堆的未来材料。目前可以推荐使用V-4Cr-Ti基合金，但这些合金对氧、氢等间隙杂质非常敏感。因此，如果要将合金用作第一壁材料，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，如碳化硅和金属间化合物。

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.