One of the crucial steps in the European Roadmap to the realisation of fusion energy is the design and construction of the Demo-orientated NEutron Source (DONES) facility. DONES is a fusion-like neutron source, based on the International Fusion Materials Irradiation Facility (IFMIF) concept, aimed at qualifying and testing the materials to be used in fusion reactors. The Target System (TSY) is a crucial system as it is the component where the interactions between deuterons and a liquid lithium target, flowing on a solid surface (i.e. the Back Plate), take place to produce neutrons for irradiating the testing materials. In this regard, an investigation campaign has been performed to evaluate the thermo-mechanical behaviour of the DONES TSY under selected steady state and transient loading conditions, in light of the most recent design updates (new bellows and connection systems). The first part of the assessment concerned the analysis of the TSY under the normal operation steady state loading scenario. A detailed 3D FEM model has been set up, considering the newest updates of the TSY geometry and of the operational parameters, and a thermo-mechanical analysis has been launched. Results have been mainly checked in terms of TSY global deformation, focusing on the Back Plate and on the connecting bellows displacements, in order to exclude overlapping with the High Flux Test Module and misalignments with the beam footprint. Afterwards, since the lithium inlet temperature has been increased from 250 °C to 300 °C, a transient thermo-mechanical analysis of the TSY under the start-up loading conditions has been performed to check if it is able to withstand the hotter lithium flow according to the RCC-MRx criteria. Therefore, the reference pre-heating strategy has been adopted, assessing the thermal and mechanical behaviour of the TSY, focusing on the Back Plate. The obtained results are presented and critically discussed, suggesting important recommendations for the follow-up of the design.

中文翻译：

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DONES 目标系统在稳态和瞬态负载条件下的热和结构分析

欧洲实现聚变能路线图的关键步骤之一是设计和建造面向演示的中子源（DONES）设施。 DONES 是一种类聚变中子源，基于国际聚变材料辐照设施 (IFMIF) 概念，旨在鉴定和测试聚变反应堆中使用的材料。靶系统（TSY）是一个至关重要的系统，因为它是氘核和在固体表面（即背板）上流动的液态锂靶之间发生相互作用以产生用于照射测试材料的中子的组件。在这方面，我们根据最新的设计更新（新的波纹管和连接系统）开展了一项调查活动，以评估 DONES TSY 在选定的稳态和瞬态负载条件下的热机械行为。评估的第一部分涉及 TSY 在正常运行稳态负载情况下的分析。考虑到 TSY 几何结构和操作参数的最新更新，详细的 3D FEM 模型已经建立，并已启动热机械分析。结果主要根据 TSY 整体变形进行检查，重点是背板和连接波​​纹管位移，以排除与高通量测试模块的重叠以及与梁足迹的错位。随后，由于锂入口温度从250℃升高到300℃，对TSY在启动加载条件下进行瞬态热机械分析，以检查其是否能够承受更热的锂流。根据 RCC-MRx 标准。因此，采用参考预热策略，评估 TSY 的热和机械行为，重点关注背板。所获得的结果被提出并进行了批判性讨论，为后续设计提出了重要建议。