RADWASTE MANAGEMENT | COVER STORY
The HAIS system is a precision robotic platform that allows
high precision repeatable image capture with high quality images, so it can be used to inspect nuclear waste products in storage
The changes are anything that changes the appearance of
an image. That can be displacement or surface deformation, but also additions and subtractions that occur between images. This is what allows things like corrosion, cracking and loss of components to also be measured. Areas of concern can then be highlighted and monitored, or a closer inspection carried out since the position is accurately recorded.
Human in the loop The human operator is an important part of the HAIS system. The system has been developed to identify areas of significant change. This augments an inspection by highlighting only those areas of significant change and — most importantly — not showing areas of little or no change to an operator. NPL says this means that the system does what a
computer does best: identifying change. It then lets the human operator make a decision as to the nature and significance of the change. This allows a seamless connection with current safety cases for inspection and still requires the ability of a skilled inspector to sign-off the case, but without the boredom of surveying areas of no change. It could be possible for alternative techniques using machine learning to be used in place of the human operator, but in practice they require too much data on too many different types of defects to allow reliable detection and confidence in the black-box decision making. There are many benefits of deploying HAIS to monitor and inspect waste stores, including gaining a greater understanding of the evolution of the nuclear materials stored and how it affects long-term safe storage. For example, measuring the properties of materials in-situ allows for a greater understanding of how much heat is being generated by the material and what the storage system needs to tolerate it. These measurements will ultimately underpin the storage strategy. For existing stores, HAIS is able to obtain a better
understanding of how store environments can change under a range of scenarios for different waste packages. Having accurate in-situ measurements increases the predictability of the environment and therefore helps to infer waste behaviour. The system also provides the tools for monitoring the environment to provide an early indication of deviation from the predicted environment, including temperature, humidity and chloride. Understanding the long-term optimum storage conditions for a range of products enables the system to provide information that could be vital in influencing new store design and improve existing store conditions.
Using the wider history The history and experience of using DIC in other civil engineering structures helped guide NPL in developing and testing the HAIS system. This included road and rail structures, oil and gas plant but some measurements were much more diverse — NPL says it has even used DIC techniques to measure setting chocolate for factory production lines. Clearly there are also different options for deploying
HAIS, for example continuous monitoring or regular inspection, depending on the nature of the objects being monitored. An alternative, fixed cameras that can make
measurements frequently, has been demonstrated by NPL in regard to CCTV used for monitoring assets belonging to the UK’s Environment Agency. NPL is also developing DIC applications that capture data on railway tunnel walls whilst moving along the track. Its most recent development is using a camera within a mobile phone for repeatable measurements, this could be used for monitoring widely distributed assets like bulkheads in ships. NPL says both types of strategy are possible but
generally, for lots of repeated objects that need to be monitored intermittently as at Sellafield, a single device that can be moved around is preferred.
Better efficiency What are the benefits of the HAIS system? Using DIC is expected to increase efficiency across the Sellafield Ltd site by enabling very small changes to be detected and far sooner than using traditional manual inspection techniques. The inspection and measurement techniques, enabled through HAIS, uses in-situ automated technologies in dark store environments where traditional communication channels or power sources are absent and allows the detection of signs of unexpected degradation. In addition, NPL points to the objective nature of the
measurement, and the ability to remotely record data, which can then be archived. When the data has been analysed, different inspectors can contribute improving the quality of the measurement and removing subjective and systematic biases. The system also more effectively uses the time of a trained inspector and reduces fatigue. Dr Robert Bernard, Senior Technology Manager, Sellafield
Ltd, said: “Sellafield Ltd are happy to be working on introducing new technology to support our mission of reducing the risk of storage of the special nuclear material we’re entrusted with by the nation. Having scientific organisations such as NPL partnering in our work ensures we’re at the cutting edge of deploying practical technology to maintain safe storage.” ■
www.neimagazine.com | October 2021 | 35
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53
