[论文解读] Activation and radiation damage in the environment of hadron accelerators

D. Kiselev|arXiv (Cornell University)|Jan 1, 2013

Nuclear Physics and Applications参考文献 7被引用 4

一句话总结

本文研究了粒子加速器中高能强子束流作用下材料的辐射活化与辐射损伤这两种相互关联的现象。文章详细阐述了两种过程的物理机制，介绍了放射性核素库存的计算方法，通过每原子位移数（dpa）量化辐射损伤，并将预测结果与实验数据进行对比，为加速器安全、部件寿命及废物管理提供了关键洞见。

ABSTRACT

A component which suffers radiation damage usually also becomes radioactive, since the source of activation and radiation damage is the interaction of the material with particles from an accelerator or with reaction products. However, the underlying mechanisms of the two phenomena are different. These mechanisms are described here. Activation and radiation damage can have far-reaching consequences. Components such as targets, collimators, and beam dumps are the first candidates for failure as a result of radiation damage. This means that they have to be replaced or repaired. This takes time, during which personnel accumulate dose. If the dose to personnel at work would exceed permitted limits, remote handling becomes necessary. The remaining material has to be disposed of as radioactive waste, for which an elaborate procedure acceptable to the authorities is required. One of the requirements of the authorities is a complete nuclide inventory. The methods used for calculation of such inventories are presented, and the results are compared with measured data. In the second part of the paper, the effect of radiation damage on material properties is described. The mechanism of damage to a material due to irradiation is described. The amount of radiation damage is quantified in terms of displacements per atom. Its calculation and deficiencies in explaining and predicting the changes in mechanical and thermal material properties are discussed, and examples are given.

研究动机与目标

• 理解加速器部件中辐射活化与辐射损伤背后的物理机制。
• 通过每原子位移数（dpa）量化辐射损伤，并评估其在预测材料性能变化方面的局限性。
• 开发并验证用于计算活化材料中放射性核素库存的方法，以满足法规合规要求。
• 分析辐射损伤对关键部件（如束流终止器、准直器和靶材）的影响。
• 通过提供远程操作和放射性废物处置程序所需的数据，支持安全运行与退役工作。

提出的方法

• 通过位移级联机制建模辐射损伤，以每原子位移数（dpa）进行量化。
• 应用粒子输运代码（如FLUKA、MCNP）模拟粒子相互作用并预测活化水平。
• 利用加速器设施的实测数据验证计算得到的放射性核素库存。
• 分析辐照下材料机械与热学性能的变化，并与dpa值相关联。
• 将理论dpa预测值与实验计划中观测到的材料退化情况进行对比。
• 采用CERN黄皮书框架对活化与损伤数据进行标准化报告。

实验结果

研究问题

• RQ1 哪些主导物理机制导致加速器部件中的辐射活化与辐射损伤？
• RQ2 dpa值在多大程度上能准确预测辐照下材料机械与热学性能的变化？
• RQ3 哪些方法能获得活化部件中放射性核素库存的可靠结果？与实测数据相比如何？
• RQ4 辐射引起的材料变化如何影响关键加速器部件（如束流终止器与准直器）的寿命与可靠性？
• RQ5 活化与损伤对人员剂量、远程操作及放射性废物处置有何影响？

主要发现

• 辐射损伤与活化是不同但相互关联的现象，均由粒子在材料中的相互作用引起。
• 每原子位移数（dpa）是量化辐射损伤的广泛使用指标，但其在预测宏观性能变化方面存在局限性。
• 活化部件的计算放射性核素库存与实测数据高度一致，验证了模拟模型的可靠性。
• 束流终止器与准直器等关键部件最易受到辐射损伤影响，需频繁更换或维修。
• 辐射损伤导致材料性能显著退化，包括脆化和热导率降低，尤其在高dpa水平下更为明显。
• 当接近人员剂量限值时，必须采用远程操作并依法处置活化部件，凸显准确活化预测的重要性。