UK Sales Manager at Serck, Steve Wright, shares a case study on the problems nuclear power stations can face being situated next to the sea.
Nuclear power stations are shining examples of very efficient, controlled, clean and precise systems. Importantly, they’re also a key component in the battle against climate change, as power companies move along their decarbonisation journeys.
But whether carbon-fuelled or not, generating electricity always generates heat, and a nuclear power station requires cooling just as much as a conventional station. As such, many power stations are situated on or near natural supplies of abundant water. Many are on a river or reservoir, and in the UK most nuclear power stations are located near the sea.
And it is the ever-changing nature of the sea that’s caused a challenge for one nuclear power station in the UK.
Power stations are often fitted with Plate Heat Exchangers (PHEs) to cool their power plants. PHEs are thermally very efficient and economically attractive, and take up a minimal footprint. However, they’re extremely sensitive to changes in service conditions. If a process isn’t running exactly as designed, they can deteriorate quickly due to clogs, leaks, etc.
The PHEs at this station are part of an internal cooling system, where there is a closed circuit of water going through various equipment in the station’s power plant, picking up heat, and going through the heat exchangers. The cooling medium is sea water, taking heat away from the process water before being returned to the sea.
Unfortunately, the sea water side of this particular system has been plagued with fine, hair-like seaweed, coming in and fouling the small spaces between the plates. This seaweed has resisted multiple attempts at filtration. Chemical treatment options cannot be considered as the water goes back into the ecosystem.
Because of the heavy maintenance burden due to dealing with the seaweed, these PHEs were being taken offline at frequent intervals. Elsewhere in the station they had successful operational experience with other heat exchangers with 1” od titanium tubes that weren’t blocking with this hair-like seaweed. But it’s no small issue to replace one heat exchanger type with another.
Replacement heat exchangers would have to be sized to navigate through a very constrained navigation route and weigh a maximum of 5 tonnes per exchanger, while meeting the original duty and design specifications. Thermal design also had to meet the multiple safety factors & fault test cases. Seismic and structural assessments had also to be checked and verified
Serck won a competitive tender process to design & manufacture the 16 heat exchangers and to supervise the installation and commissioning. Serck is one of this customers’ top 100 suppliers, and experts in cooling for power stations and other industrial applications.
Eight of the 16 heat exchangers have already been built to the customer’s program. Design and Manufacture was to ASME Section III Division 1, Subsection ND and NF standard [Ref 6.3] & TEMA, seismic category 1. The heat exchangers are of an AEM construction with carbon steel shell, titanium clad tubesheets and tubes and SA 240 S32750 Duplex Channels.
Serck provides specialist design, manufacture, installation, service, and global export of heat transfer technology across a range of sectors and geographies. Operational capabilities include industrial and marine heat exchangers, climate control and heat recovery products and efficiency coatings, as well as specialist, heavy-duty, high-performance, and heritage automotive radiators.
Trusted by a global roster of clients including F1 teams, national utilities, petrochemical producers, military, marine, and rail organisations. Headquartered in the UK with additional facilities in the US and Middle East, Serck is part of the Unipart Group of Companies.
Find out more at https://serckglobal.com/