Sykes Pumps installs dewatering solution at UK’s Hinkley Point C nuclear project
One of the first tasks for Sykes was to provide a solution to manage the large surges in flow caused by the tide during construction of the sea wall at the site, which is located on the coast of England, UK.
A spokesperson for the contractor explained: “At high tide we needed to be able to pump 350 litres of water per second away from the site. The best approach for this was a submersible pump designed for high flow rates and high heads, which is exactly what Sykes Pumps provided.
“The provision for each WMZ is based on 100-year storm levels; using data from the last century, we have considered what the worst case scenario would be if rainfall were to be as bad as it has ever been over that 100-year period and we then provided Sykes Pumps with the maximum flow rate requirements based on those calculations.
“Some of the excavations are as deep as 35 metres, which means a lot of water silt and sediment. That’s why water storage lagoons are a critical element of the water management strategy, allowing us to test the water before it’s returned to natural water courses.”
Sykes Pumps provide three PX30 heavy-duty electric submersible pumps able to pump 350 litres per second with heads of up to 70m. These low-maintenance pumps are simple to install and very robust, which makes them ideal for the busy Hinkley Point C site.
Adhering to these requirements, the contractor hired super silenced Super Wispaset 100 4-inch diesel pumps and super silences Super Wispaset 150 6-inch pumps from Sykes for various locations around the site, to pump groundwater and rainwater into ‘dirty’ water storage lagoons.
Most of the pumps on site have been provided with a float switch-based control system to ensure that they will kick in automatically should water levels rise, without running unnecessarily during drier periods. This reduces energy costs and simplifies day-to-day management of the pumps.
The company has additionally purchased specially-modified surface mounted electric pumps to manage the groundwater in each WMZ. These will be used in combination with specialist filtration units designed to separate suspended solids and sediment from water before it is released back into natural water courses. The cleaned water can then be tested for impurities before being discharged.
A total of 14 modified electric surface mounted pumps have subsequently been ordered: seven 22kW units and seven 55kW units. They have been modified to include an automated priming system, as well as ultra-sonic control systems with a control room housed in a container unit for each WMZ.
“The control systems mean they are extremely low maintenance and will respond rapidly to water conditions in real time,” explained Bob Lima, the engineer at Sykes responsible for the modifications. “Each WMZ has been specified with a pumping capacity that meets the maximum 100-year resilience required for the specific location, with automated adjustments to flow rates and rapid start of up of the pumps with automated priming.
“The system also provides fault monitoring and the flow will automatically switch from duty pump to standby in real time if a fault is detected, enabling the on-site team to call our engineers out for a maintenance visit.”
A spokesperson for the project concluded: “This is much more than a pump hire agreement because of the size and complexity of the site. In addition to the right equipment, Sykes Pumps has provided us with a consultancy-based service that ensures we have the right solutions in place for different areas of the site and the varying pumping needs of different elements of the construction programme.”