高能中子环境下水的辐射分解机制研究

As the development of advanced nuclear system (e.g. Fusion reactor) and deep space exploration, the staff and equipment are under the increasing threat of high energy neutrons. The high energy neutron-induced water radiolysis can enhance the material corrosion, which would compromise the equipment and the health of operators. The mechanism of water radiolysis is closely related to the neutron energy. Nowadays, the research of water radiolysis is confined in hot and fast neutrons, due to the lack of high energy neutron source. However the lack of the fundamental data of high energy neutron-induced water radiolysis hinders the research on the corrosion controlling for fusion reactors and the radiation damage assessment. This proposal proposed experimental measurements for the primary g value of high energy neutron-induced water radiolysis, using high intensity D-T fusion neutron generator and free radical scavenger systems. The mechanism will provide via different adsorbed dose rate and temperature. Based on which, a water radiolysis model can be established. In addition, the radiation chemistry fundamental database would be improved and the radiation effects on the interface between water and materials can be in-depth understood. The proposed researches would provide guidelines for the fusion reactor corrosion controlling and the protection of high energy neutron.

随着以聚变堆为代表的新型核能系统和深空探索的发展，人员与设备正越来越多的面临高能中子的威胁。水在高能中子辐射场下会发生辐射分解，其产物会加剧结构材料腐蚀，影响设备寿命，增加人员所受剂量，对于设备与人员安全影响重大。水的辐解机制与中子能量密切相关，鉴于强流高能中子源的匮乏，现有研究局限在热中子和快中子领域，缺少高能中子环境下水的辐射分解机制研究，严重影响了聚变堆腐蚀控制和高能中子辐射损伤评估。本研究拟利用强流氘氚聚变中子源，通过不同自由基清除体系测定高能中子环境中水的辐解初级产物产额基础数据，研究剂量率、温度等对高能中子水辐解机制的影响，建立水辐射分解模型，同时探索水辐射产物对材料界面性质的影响，完善辐射化学基础数据库，充实电离辐射对液相作用的原理，对于指导聚变堆设计和高能中子防护具有重要意义。

随着核能、核技术、太空探索的发展，人员和设备正越来越多的面临高能中子的威胁。其中水在高能中子辐射场下会发生辐射分解，加剧材料腐蚀，影响各类部件的性能。本项目基于强流氘氚中子源HINEG，搭建了中子辐解水产物的实验平台，利用自由基清除剂完成了水辐解初级产额g值测定的实验工作，同时也研究了质子（利用质子束）和β射线（利用氚水）对石墨烯材料界面的影响实验、结果表征与机制研究，并拓展应用于放射性氘氚同位素分离领域，测定了氚分离的效率。研究发现，在现有高能中子源的情况下，中子辐解水的产物产量依然极低，尚不能准确完成g值的测定工作。在此情况下，研究组选定了对辐射较为敏感的单层石墨烯作为研究对象，发现在质子束轰击下，石墨烯的自修复效应可有效降低其辐射损伤，同时发现在β射线环境下（放射性氚水中），石墨烯可以长期的保持稳定。相关成果发表论文3篇，培养博士生2名（毕业1名），硕士生1名（毕业1名）。研究组同时将相关实验结果拓展应用于氢同位素（氕氚，H/T）分离领域，利用放射性氚水完成了氕氚分离实验并测定了同位素分离效率，单次循环即可实现氚水浓度富集10倍以上，通过多级并联的手段，未来可尝试应用于大量低浓度含氚废水的减容富集中。