Months of media speculation about a new era of nuclear power plant may have generated all the heat– but it’s the teams working tirelessly to keep the old plant running who are creating all the light.

One in every five homes in the UK today runs on electricity from the second generation of nuclear power plant.

These are the Advanced Gas-Cooled Reactors (AGRs), whose design dates from the 1960s, and they are found at seven sites in England and Scotland.

Together with a more recent Pressurised Water Reactor, these plant make up the UK’s total nuclear generating capacity, accounting for some 20 per cent of all supply.

Their continued operation over the next decade or so until new plant comes on stream is a vital part of UK energy security and the country’s low-carbon climate change strategy.

The fleet is owned and operated by EDF Energy, which is extending the lifetimes of the AGRs by an average of seven years.

And just as much as the country needs EDF Energy to keep the reactors up and running, so too does EDF Energy need the original equipment manufacturers to keep servicing their installations and guaranteeing the replacement parts until the reactors finally reach the end of their operating life.

One of these is Cavendish Nuclear, the UK’s largest nuclear services business and holder of the fuel route knowledge and design for the AGR fleet.

It’s a relationship that dates back to the 1970s and commissioning of the first commercial AGR – the twin-reactor site at Dungeness B in Kent.

Paul Bates, EDF Energy account director at Cavendish Nuclear, acknowledges the challenge that lifetime extensions bring – and how it has brought client and contractor even closer together to see each reactor through to the end.

“As plant becomes older, it becomes even more important to retain and transfer the knowledge and experience from one generation to the next,” he says. “We need to address issues of obsolescence and maintain a supply chain capable of staying true to the original design so that our spares and equipment continue to be compliant and the risk of plant breakdown is mitigated.

“We’re delighted that EDF Energy and Cavendish Nuclear have committed to a long-term relationship through a partnering agreement that will take us through to the end of life for each reactor. This strategic approach brings a level of collaboration that is good for the customer and good for us. It’s how we like to do business.”

Cavendish Nuclear employs about 300 people full-time on its work supporting the EDF Energy fleet. In addition to its OEM role, the teams carry out graphite inspections and provide engineering and technical support for reactor operations, while the company maintains the only test rig of its kind for the AGR gas circulators at its engineering base in Leicestershire.

During maintenance outages, the Cavendish Nuclear presence at a station can swell to 200. The company has interests at every nuclear site in the UK, including the decommissioning of every first-generation Magnox, research and breeder reactor plants, giving it an unrivalled pool of 6000 staff to call upon and the back-up of being part of the Babcock International Group with its major stake in the UK’s submarine reactor programme.