GREENCDT Structural damage assessment using infrared detectors in fusion environments

Plasma facing components in planned fusion powerplants will experience significant structural and functional degradation in service. The proposed approach for inspection and maintenance of plasma facing components relies on the establishment of periodic inspection intervals, which are costly as they require extended plant outages. The frequency of in-vessel inspections will be heavily influenced by estimates of plasma facing component lifetimes, which are amongst the lowest of all in-vessel components. This dictates an urgent need for the development of structural health monitoring systems for plasma facing components, which can identify and track material degradation without the need for plant shutdown, while providing the ability to signal unplanned maintenance at the earliest sign of component failure.

In this project it is proposed to use infrared detectors for structural health monitoring. Infrared detectors are routinely deployed in fusion vessel diagnostics; however, their use is limited to measurement of surface temperatures and heat loads [1]. Recently, there has been promising work on the use of infrared sensors for structural health monitoring in the aerospace industry [2]. Work conducted by Eann Patterson and William Christian at the University of Liverpool has demonstrated the ability to automate damage identification and tracking fields of data acquired with infrared [2] and visual [3] sensors.  Hence, there is an untapped potential for utilising infrared detectors for in-situ damage detection in plasma facing components in fusion powerplants. The aim of the proposed work is to extend infrared functionality to serve as a structural monitoring tool for plasma facing components in fusion plant.

It is anticipated that the project will progress via the following three workpackages:

WP1: Method development and uncertainty quantification for IR-based damage detection in the fusion environment

• Use the extreme thermo-mechanical test facility at Liverpool to develop a new method for identifying defects in PFC materials using samples with known defect sizes 
• Perform a thorough uncertainty quantification of the method

WP2: Component mock-up manufacture and testing on HIVE/HHFTVF

• Apply the method to actively cooled divertor mono-blocks tested on HIVE/HHFTVF using a series of mock-ups with known defects
• Test divertor mono-blocks without defects to failure on HIVE/HHFTVF and assess the methods ability to detect failure.

WP3: Demonstration on MAST-U IR data

• Use existing IR imaging data of PFCs from MAST-U and apply the methodology to identify damaged tiles.
• Apply the method to IR imaging data from the CHIMERA machine and feed into PEGASUS validation activities