Leak Detection – Hinkley Point Power Station
Hinkley Point C is in the news a lot at the moment thanks to the recent deal with China and a growing concern over the rising costs. In the mean time Hinkley Point B is still operational until 2023 and Pipefix have recently been selected as the Water Repairs & Maintenance contractor for the station which has been generating electricity since 5 February 1976.
Hinkley Point B is an Advanced Gas-cooled Reactor (AGR) which was designed to generate 1250 MW of electricity. It is the only one of four nuclear power stations in the area which is operational, the others being decommissioned are the adjacent Hinkley Point A together with Oldburyand Berkeley on the banks of the River Severn. As of 2013 it provided 1% of the UK’s total power output.
First things first, Hinkley Point is a very secure site. We have been working on MOD bases for over 12 years, and our experience to date has been that getting onto site here has been one of the trickiest to date. The level of scrutiny our paperwork has undergone is as detailed as the highest security Military bases we have been on, and we are really pleased that we have been able to pass the criteria for Health & Safety, Personnel Management and Quality Procedures. It has taken a long time – we started the process in March and are due on site in November!
Full Risk Assessments and Method statements are required for each step of every process that we are undertaking. Nothing is left to chance, and the client wants to know every possible outcome of our work activity long before we actually get to site. This includes detailed interrogation of any electrical equipment we use and any electrical devices that we plan to install to ensure they do not conflict with sensitive equipment on site. As an example of this level of detail the initial loggers we specified were rejected by the site engineers because of a frequency clash, and we even had to alter some of our standard procedures to meet the clients site protocols.
As an active power station there are a number of operational water matters that need constant attention, including the monitoring of water flow around the site and tracing and repairing leaks on the water distribution system around the site. The life expectancy of water distribution pipes varies according to the material, the environment and the operating regime. This is a relatively demanding environment, and so it is within normal expectation that the system would have leaks after 40 years of constant use.
Piepfix are deploying the latest electronic listening equipment to accurately trace the leaks on site. As you can imagine, on a site like this there is not much scope for making mistakes with intrusive trial excavations, so we need to be as sure as we can before taking action. The Seba Correlux P-250 kit utilises the latest, most sophisticated correlation methods to help the operator to avoid incorrect measurements and unnecessary digging. Automatic plausibility tests make measurement even more reliable. The integrated damage sketch program means leaks can be easily recorded in detail. The P-250 allows us to quickly and efficiently locate leaks in pipes of any material with its innovative automated frequency analysis that adjusts for changes in material without any input from the operator.
We are also installing two ultrasonic water flow meters to help the engineers gather data about the water movement around site. Ultrasonic meters are useful in retro-fit scenarios when it is not practical to interrupt the water supply to install a mechanical meter. In this instance we are fitting the meters to the outside of two ductile iron mains that would otherwise have required excavation and required us to shut off critical supplies for up to half a day.
