World First! Development and use of PackScan® technology for monitoring fill pack fouling
KKL is a 1275MWel. nuclear power plant between Basel and Zürich in Switzerland, with a 120m span / 144m high natural draft cooling tower. Following problems with fill replacement at a sister plant, the project team sought to learn from previous mistakes by testing several designs of new anti-foul fill pack. After proceeding with pack replacement in 2012 attention then turned to ensuring fouling build-ups are kept to a minimum. This involves varying strategies for on-going water treatment but also requires accurate monitoring of the pack condition. This will provide valuable data to the maintenance and chemistry teams on condition and performance that can then be used going forward to combat further accumulations or take remedial action in good time.
EPSCO and KKL: The development of PackScan®
KKL engaged with EPSCO – cooling tower specialists – who were in the final stages of developing an innovative remotely operated scanning system that assesses fouling accumulations across entire fill pack areas. After discussions, both parties agreed that this would be the ideal opportunity to demonstrate the system and carry out an initial pilot scanning process. In late 2012 EPSCO mobilised the prototype system and operatives to carry out the PackScan® process on the refurbished tower – this would provide a clear baseline for comparison. EPSCO has since deployed the system across a wide spectrum of induced draft and natural draft towers in the UK. Where fouling was present the system was able to provide 3D models that accurately identify patterns and differences across pack areas. EPSCO recently re-visited KKL for a follow up scan – one year on – to monitor for initial fouling. Fortunately deposition was minimal – but there were areas of note identified with scanning and verified by endoscope images.
“In our opinion this PackScan technique, supported with our weight measurement is currently the best way of monitoring our cooling tower"
Peter Graf Project Manager (KKL)
An on-going regime for entire tower fill pack monitoring
Following the initial pilot and more recent output examples from other fouled assets, KKL have decided to use PackScan® once annually to monitor the fill pack. The system offers several gains for the KKL Maintenance and Chemistry Teams:-
- coverage of the entire fill pack with 3D visual representations and images
- comparison and trending with other monitoring such as weigh stations
- recognises distinct fouling patterns, anomalies and areas of concern
- targeted cleaning or water treatment adjustments at effective intervals
- Identify deposit build-ups and exact surface and depth locations