Material system issues in the next fusion device

在这个项目中，在实验反应堆，如ITER的材料问题将提取的观点不仅是个别材料，但材料系统集成在一个连贯的功能组件。为讨论该项目的基本战略，举行了小组会议：1991年两次，1992年两次，1993年三次。1991年举行了两次大会，约有50人参加，1993年举行了四次，1994年举行了两次。由于这项活动，每种材料的使用条件的分类和定义已经完成，并提取了各种材料问题。特别是对下一个装置所采用的奥氏体钢在辐照下的极端塑性损失和非稳态低温辐照蠕变进行了研究，并讨论了可能的对策。在ITER/EDA的概念设计中，钒合金被认为是一种候选结构材料。在本项目中也对这一概念进行了审查。虽然钒合金/液态锂系统已被总结为具有非常吸引人的特征，但已指出缺乏用于构建大规模构件的数据库和制造技术的过早工程化。因此，ITER主要结构件采用钒合金还为时尚早，DEMO可能采用钒合金，ITER试验模块采用钒合金是必要的。

In this project, matererials issues in experimetal reactors, e.g.ITER will be extracted from view points not only of individual materials but of material system to be integrated in a coherent functioning components. Small group meetings were held to discuss the basic strategy of this project : two times in 1991, two time in 1992 and three times in 1993. General meetings with approximately 50 participants were held two times in 1991, four times in 1993 and two times in 1994. As a result of this activity, categorization and definition of the service conditions of each material has been accomplished and a variety of material isses have been extracted. In particular, extreme ductility loss of austenitic steels to be adopted in the next device by irradiation and non-steady-state low temperature irradiation creep have been examined and possible contermeasures have been discussed. In the conceptual design examined in ITER/EDA,vanadium alloy has been considered as a candidate structural material. This concept has been also examined in this project. Although the system of vanadium alloy/liquid lithium has been concluded to have very attractive features, the lack in database for constructing large scale components and premature engineering in fabrication tchnique have been pointed out. As a result, it has been also concluded that it is still too early to adopt a vanadium alloy in major structural components in ITER.Vanadium alloys may well be adopted in DEMO and it has been also concluded that it is essential to adopt vanadium alloy test module in ITER.