Improved Visual Inspection of Advanced Gas-Cooled Reactor Fuel Channels

Graeme M. West, Paul Murray, Stephen Marshall, and Stephen D. J. McArthur
Publication Target: 
Publication Issue: 
Special Issue Nuclear Energy PHM
Submission Type: 
Full Paper
Supporting Agencies (optional): 
EDF Energy
ijphm_15_012.pdf893.59 KBApril 30, 2015 - 2:32am

Visual inspection of fuel channels is an important technique used in assessing the health of the UK’s fleet of Advanced Gas-Cooled Reactor (AGR) power plants. For each fuel channel inspected, any defects which are identified need to be classified and assessed by a panel of experts and documented before the plant can be returned to service. For each defect, part of the current inspection process involves extracting relevant frames from video footage captured during visual inspection and manually assembling these frames to form a crack montage image. As the plants age, there is an increasing pressure to inspect more and more fuel channels during planned, periodic outages. Dealing with this increase in inspection requirement needs the development of new techniques to support the analysis of an increased volume of gathered video data so that crack montages can be made within the tight timescales of the outages.
Recent work by the authors has led to the development of a technique for automatically processing inspection videos in order to extract the relevant frames and produce so called chanoramas from which any required defect montages can be cropped. Chanoramas are 360° panoramic images, which show the entire inside surface of the fuel channel inspected and this provides a completely new way for plant operators to view their visual inspection data and understand and analyse the condition of fuel channels within the AGR cores. The algorithms used to create these chanoramas have been deployed for use in a system called ASIST (Automated Software Image Stitching Tool), which is currently being evaluated by inspection engineers in parallel with the existing manual process during planned periodic outages.
In this paper we present an industrial case study which first introduces the concept of a chanorama and summarises some initial findings of testing ASIST. Then, based on the initial testing results, new and advanced image processing techniques which have been designed to improve the quality of the final chanoramas are presented. The paper then expands upon the use of the raw data and describes techniques for rendering it to allow 3D visualisations of the fuel channels. Firstly, techniques for generating anaglyph 3D images are explained before this principle is extended to allow the construction of 3D “pivot” videos which allow inspection engineers to view features of interest from a range of different angles.

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Submission Keywords: 
condition monitoring
visual inspection
Lifetime Extension
image processing
Submission Topic Areas: 
Technology maturation
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