Hinkley C is the first of the New Generation of Nuclear Power Stations in the UK for many years and has numerous unique features to ensure it is safe, environmentally friendly and operates reliably and efficiently. As with all thermal power plants, a key strategic element in the achievement of this is the design of the Heat Sink and the cooling water system. As with the other Nuclear Power stations in the UK, the system selected is a once through intake design, with the Pump House forming one of the largest civil work structures on the site.
The drum screen filters for the intake are some of the largest units in the world and are to be supplied by Ovivo UK Ltd, based in Colchester, Essex, a global leader in Intake Screening systems and supplier to the nuclear industry since the 1950’s.
The cooling water supply to nuclear power stations is of vital importance, both for safety related purposes and to provide a heat sink for condenser cooling. In the UK, the most obvious source of this cooling water is the ocean surrounding our island. However, with the abstraction of this water, there is inherently debris and marine, which needs to be removed before passing through the power plant.
There are two types of fine screening to be supplied by Ovivo on the Hinkley C site. The Bandscreens for the essential services water and the large Drumscreens for the filtration of the Condenser Cooling water.
Both types of screens are fitted with fish recovery features to reduce mortality on the marine life and return them to the sea unharmed.
The extremely high volumes of cooling water and the depth of the intake at Hinkley C make it necessary for the Ovivo drum screens to be some of the largest ever installed. Four drum screens are provided in total, two for each unit and each one being 27m diameter, 6.7m wide and can remove all particulates over 5mm in size at a flowrate of 44m³ per second each. To put this into context, the drum screens extend 9 stories down and each one treats half the average flow of the river Thames in London.
As with all nuclear power stations, safety is always the key priority and several measures have been factored into the design of the pump house screens including demanding Seismic Spectra and Air Plane Crash ( APC) loading which replicates the shock caused by an aircraft hitting the reactor building. This has led to some interesting challenges for Ovivo during the design phase, especially with the design life of 70 years.
Ovivo first started working on Hinkley C as far back as 2008, with some early studies carried out in 2009. The order was finally signed in April 2017 with the design phase nearing completion early in 2019. Ovivo plan to use the UK supply chain as much as possible when the fabrication begins next year, with first deliveries to site expected to start in June 2021.
Ovivo see a great future for New Nuclear in the UK and are excited at the prospect of working on future projects such as Sizewell C and Bradwell in the East of England as well as Wylfa B on Anglesey.
Article supplied by Jeremy Lee – Ovivo