Pumping solutions for HPC

EDF ENERGY’S NUCLEAR NEW-BUILD project at Hinkley Point C in the UK is being delivered by several teams working together including Bylor, Balfour Beatty and Kier Bam Joint Venture (KBJV). KBJV’s role is the site preparation and earthworks.

A key part of the work carried out by KBJV is excavation of the ‘heat-sink; a huge area that will eventually contain all the cooling water infrastructure and pump house.

KBJV took up an offer from James McKiver, strategic account manager at Selwood, for a free trial of a Selwood D150 drainer pump. During a period of heavy rain in October 2017, Selwood’s equipment continued to work as normal, without the breakdowns KBJV had experienced in similar conditions in the past.

Following this trial, KBJV turned to Selwood as the main pump supplier, phasing the replacement of the existing on-site pumps with the Selwood product.

Following an order for ten Selwood D Range pumps in December, Selwood developed a close partnership with Kier Bam’s water management team, working in close collaboration on design, pump positioning and optimal performance in the event of a flooding emergency, something which had occurred in previous years.

Selwood’s team then worked closely with KBJV to redesign the pipework runs and the positioning of the pumps on site.

The first major project was the dewatering of the heat sink for the first reactor unit. The pumping equipment had to keep up with a potential 45 litres of water a second, pump it up 39m to a booster pump and then on to a water management zone for treatment before discharge.

In dry conditions, where only groundwater was being cleared, a series of pumps and pipework carried the water from the heat sink to an onsite treatment plant 1.5km away. To keep fuel costs down, Selwood developed a pressure sensor for a booster pump that plugged into auto-start terminals on the pumps. This would automatically start the booster when water was detected, so the pump was only in operation when needed. Similar pressure sensors have been installed on boost pumps around the site that are pumping contaminated groundwater. This is a far more elegant and safer solution than the previous system, which used tanks and floats. These were regularly overflowed, leading to pollution events.

So far, Selwood’s specialist solutions team has assisted in sizing and calculating flows for more than 50 pumps on site and 54km of pipework. Selwood invested £2 million in equipment for Hinkley Point C, manufacturing 30 new pumps especially for the project, and at the peak of the works had 106 pumps on site. Selwood inducted at least ten new members of staff for the project and has logged 16,000 person hours in relation to it.

SelWatch, Selwood’s in-house developed remote telemetry technology, ensures equipment can be monitored at all times, with any issues flagged instantly by text message, phone call or email. This has minimised delays caused by flow breakdowns and power failures, assisting KBJV in keeping on schedule.

As well as installing its solutions, Selwood provided training to senior members of the KBJV team on technical aspects including flow curves, sweet spots of pump curves, working out friction loss and pipework sizing. Selwood delivered troubleshooting and basic maintenance training to all operatives using the pumps.

The KBJV team faced significant challenges in delivering this crucial stage, so Selwood’s work was under close scrutiny. In January 2019, a major milestone was reached when the platform was formally handed over from KBJV to the main civils contractor, Bylor. This allowed construction of the permanent civil works in the area to begin. The Selwood solution was a vital part of the puzzle in ensuring the works were delivered without penalties for lost time. Upon completion of the heat sink for unit 1, Selwood’s teams turned their attention to delivering a similar solution for the second unit.

Hinkley Point C is a textbook example of close collaborative relationships, delivering technical solutions from expert teams working round the clock. The project sees Selwood technical support teams, engineers, electricians and a project manager on site 24 hours a day, seven days a week.

Damion Hopkins, leader of the KBJV Water Management Team, said: “Removing the water from a site of this magnitude has been a challenge for the KBJV Water Management Team but it has been crucial in allowing the site to keep on track in all weathers.

Selwood is working with KBJV to future-proof the site in terms of pumping requirements until construction is completed. Selwood is providing both semi-permanent pumping systems and is providing rapid response pumps for extreme flooding events should they occur in future.