Development of a Fast Neutron Computed Tomography System for Non-Invasive Testing

本研究项目旨在开发一种新型的计算机断层扫描系统，该系统能够测量复杂工程结构内部的三维相位分布。相变现象极大地影响了许多工程系统中的物理特性，但三维相场的直接测量历来涉及侵入式测量，并且/或者可能无法普遍应用于在高压和高温下沸腾条件下运行的系统。这项工作的工业合作伙伴是CANDU业主集团，他们的目标是获得CANDU燃料串模拟器内部相场的测量数据，在那里发生沸腾，压力可以超过10 MPa，以便为模型改进和多相计算流体动力学验证生成数据。对现有商业测量方法的回顾表明，在这一领域，需要在3D无损检测方面取得新的进展，并应用于核工业以及其他可能发生相变现象的部门。该项目将开发一种快中子计算机断层扫描（FCNT）系统，该系统能够成像复杂几何形状中涉及厚压力边界的三维相场分布。由于移动中子发生器技术的根本改进，在过去十年中，中子输出从1e7增加到1e10，新技术的发展今天成为可能。它将基于加速器的中子发生器领域的新发展、新的硅光倍增器（SiPM）技术与现有的CT方案相结合，以获得能够满足当前和未来研发需求的新型移动系统。目标是让该技术以1cm或更好的分辨率呈现分布，并且扫描时间为工业可接受的（大约1小时，而不是一些历史系统所需的数小时或数天）。这项工作代表了加拿大首个同类技术，并将在加拿大各个研发部门广泛应用。

This research grant aims to develop a novel computed tomography system which is capable of measuring 3-dimensional phasic distributions inside complex engineering structures. Phase-change phenomena greatly impact the physics in many engineering systems but direct measurement of the 3-dimensional phase field has historically involved intrusive measurements and/or may not be applied universally to systems that operate under boiling conditions at high pressure and temperatures. The industrial collaborator for this work is the CANDU Owners Group and their goal is to obtain measurements of the phase field inside a CANDU fuel string simulator where boiling occurs and pressures can exceed 10 MPa in order to generate data for model improvement and multi-phase computational fluid dynamics validation. A review of existing commercially available measurements has indicated that there is a need for new advancements in 3D non-destructive testing in this area with application to the nuclear industry as well as other sectors where phase change phenomena can occur. This project will develop a fast-neutron computed tomography (FCNT) system capable of imaging 3-dimensional phase-field distributions in complex geometries and involving thick pressure boundaries. The new technology development is possible today due to radical improvements in mobile nuetron generator technologies which have increased in neutron output from 1e7 to 1e10 over the last ten years. It integrates new developments in the area of accelerator based neutron generators, new Silicon-Photo multiplier (SiPM) technologies with existing CT schemes to obtain a new mobile system capable of meeting current and future R&D demands. The goal is to have the technology render distributions with 1cm or better resolution and scan times which are acceptable to industry (on the order of 1 hour as opposed to multiple hours or days required with some historical system). The work represents the first-of-its-kind technology in Canada and will have wide ranging applications across various R&D sectors in Canada.