Thermal and dimensional evaluation of a test plate for assessing the measurement capability of a thermal imager within nuclear decommissioning storage

TL;DR

This study developed and validated a thermal and dimensional test plate with known surface anomalies to evaluate the measurement capabilities of thermal imagers for nuclear storage applications, highlighting the potential and challenges of in-situ thermal imaging.

Contribution

It introduces a specially designed test plate with known defects for assessing thermal imager performance in nuclear storage environments, addressing current measurement uncertainties and methodological challenges.

Findings

Successful defect identification at 30-170°C

Temperature measurement uncertainties ranged from 1.0 to 6.8°C

Demonstrated feasibility of in-situ thermal imaging for nuclear containers

Abstract

In this laboratory-based study, a plate was designed, manufactured and then characterised thermally and dimensionally using a thermal imager. This plate comprised a range of known scratch, dent, thinning and pitting artefacts as mimics of possible surface anomalies, as well as an arrangement of higher emissivity targets. The thermal and dimensional characterisation of this plate facilitated surface temperature determination. This was verified through thermal models and successful defect identification of the scratch and pitting artefacts at temperatures from \SIrange{30}{170}{\celsius}. These laboratory measurements demonstrated the feasibility of deploying in-situ thermal imaging to the thermal and dimensional characterisation of special nuclear material containers. Surface temperature determination demonstrated uncertainties from \SIrange{1.0}{6.8}{\celsius} (\(k = 2\)). The principle challenges inhibiting successful deployment are a lack of suitable emissivity data and a robust defect identification algorithm suited to both static and transient datasets.