Given harsh operating conditions and physical constraints in reactors, nuclear applications cannot afford to equip the physical asset with a large array of sensors. Therefore, it is crucial to carefully determine the placement of sensors within the given spatial limitations, enabling the reconstruction of reactor flow fields and the creation of nuclear digital twins. Various design considerations are imposed, such as predetermined sensor locations, restricted areas within the reactor, a fixed number of sensors allocated to a specific region, or sensors positioned at a designated distance from one another. We develop a data-driven technique that integrates constraints into an optimization procedure for sensor placement, aiming to minimize reconstruction errors. Our approach employs a greedy algorithm that can optimize sensor locations on a grid, adhering to user-defined constraints. We demonstrate the near optimality of our algorithm by computing all possible configurations for selecting a certain number of sensors for a randomly generated state space system. In this work, the algorithm is demonstrated on the Out-of-Pile Testing and Instrumentation Transient Water Irradiation System (OPTI-TWIST) prototype vessel, which is electrically heated to mimic the neutronics effect of the Transient Reactor Test facility (TREAT) at Idaho National Laboratory (INL). The resulting sensor-based reconstruction of temperature within the OPTI-TWIST minimizes error, provides probabilistic bounds for noise-induced uncertainty and will finally be used for communication between the digital twin and experimental facility.

翻译：鉴于反应堆内恶劣的运行条件和物理约束，核应用无法为物理设备配备大量传感器。因此，在给定的空间限制内仔细确定传感器的布局至关重要，这有助于重建反应堆流场并创建核数字孪生。我们面临各种设计考量，例如预定的传感器位置、反应堆内的禁区、分配给特定区域的固定传感器数量，或以指定距离间隔放置的传感器。我们开发了一种数据驱动技术，将约束条件集成到传感器布局的优化过程中，旨在最小化重建误差。该方法采用贪心算法，能够在网格上优化传感器位置，同时遵守用户定义的约束。通过计算从随机生成的状态空间系统中选取一定数量传感器的所有可能配置，我们证明了该算法的近似最优性。在本研究中，该算法在堆外测试与仪表化瞬态水辐照系统(OPTI-TWIST)原型容器上进行了验证，该容器采用电加热方式模拟爱达荷国家实验室(INL)瞬态反应堆测试设施(TREAT)的中子效应。基于传感器的OPTI-TWIST内部温度重建结果不仅误差最小化，还提供了噪声引起不确定性的概率边界，最终将用于数字孪生与实验设施之间的通信。