X-ray Computed Tomography for Nuclear Power Plant Maintenance

Abstract

As part of the scheduled maintenance of nuclear power plants, specialist tools are deployed into the reactor core, for example to inspect the moderator. It is imperative that these tools operate correctly, and that no element of the tool remains in the reactor when the reactor resumes operation. The current processes for ensuring this are hugely labour intensive, and hence costly, involving a full teardown before and after deployment. This paper describes the development of a novel X-ray Computed Tomography (CT) system and workflow for ensuring the integrity of specialist reactor tools without the need for disassembly. The system hardware must be able to deal with the challenge of tools that are up to 6 metres in length and contain a significant amount of dense componentry. On the other hand, the system software must be able to confirm the correct and comprehensive assembly of the tool based on the obtained CT scan, and despite numerous potential, but benign, differences in the tool appearance. The presented approach overcomes both challenges: the hardware uses a gantry design with a high-powered X-ray source (see Fig. 1), the software employs a machine learning implementation.