Thermal and dimensional evaluation of a test plate for assessing the measurement capability of a thermal imager within nuclear decommissioning storage. (October 2022)

• Record Type: Journal Article
• Authors: McMillan, J.; Hayes, M.; Hornby, R.; Korniliou, S.; Jones, C.; O'Connor, D.; Simpson, R.; Machin, G.; Bernard, R.; Gallagher, C.
• Is Part Of: Measurement. Volume 202(2022)
• Publication Date: 2022-10
• Subjects: Thermal imaging -- Infrared -- Radiation thermometry -- Thermography -- Temperature measurement -- Metrology -- Nuclear -- Material container -- SNM -- Decommissioning -- Environmental; Weights and measures -- Periodicals; Measurement -- Periodicals; Measurement; Weights and measures; Periodicals; 530.8
• DOI: 10.1016/j.measurement.2022.111903
• Languages: English
• ISSNs: 0263-2241

Abstract

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 30 °C to 170 °C. 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 1.0 °C to 6.8 °C ( 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. Highlights: Combined defect detection and temperature measurement of containers with thermal imaging was shown to be feasible. The smallest 0.50 mm diameter pits and 0.8 mm wide and 0.26 mm deep scratches were successfully detected. Poor understanding of the particular surface emissivities resulted in a large discrepancy between thermocouple and radiance temperatures.