Hinkley Point C is a mega-project that digs tunnels beneath the sea.

The latest phase of Hinkley Point C, located deep beneath the Bristol Channel is almost complete. Engineers in orange overalls are fine-tuning three tunnels that extend miles beneath the seabed.

Two of the tunnels will be filled with seawater to cool the plant when the plant is fully operational. They are 6m wide by 3.5km in length. The seawater will be returned to the ocean through a third tunnel.

The construction of all this was a complex task. Each tunnel is connected by 44m-long metal water heads that are designed to sucking in water, but not fish. A “fish return pipe”, designed to assist any unfortunate sprat, will help them get back to ocean.

Matt Blake, Hinkley’s head of tunnelling said, “Not to make anyone feel uncomfortable, there is 30m of ocean above us and then a few hundreds tonnes of steel right over our heads.”

We can see the water flowing down the walls and forming a large pool at our feet. Blake assures that this was part of the plan to reduce pressure on the building.

These tunnels are a testament to the engineering challenges of building Britain’s new nuclear power plant, which is Britain’s first in 30 years. Hinkley Point C will cost £46 billion when the first reactor is turned on in 2029, due to delays and overruns.

Hinkley has been built to about half its capacity, and the delivery of this plant will be left up to the new Labour Government. The party is pro nuclear, but will have to decide soon whether it gives the green light to a similar plant in Suffolk, Sizewell C, or a new breed of smaller reactors. Is it able to provide the political will and financial power required to support this new nuclear era?

The engineering team lifts a steel dome weighing 245 tonnes onto Hinkley Point C’s first reactor building with the help of the world’s largest crane, “Big Carl”.

Hinkley C was first conceived during the 2000s under the Labour government and given green light in 2016. The French utility EDF owns the majority of the project, while CGN from China holds 33 percent. CGN is no longer allowed to be involved in the nuclear industry of Britain due to political concerns. However, it still retains 30 engineers at Hinkley.

Hinkley, when fully operational will supply electricity to 6 million homes. Tom Greatrex is the current CEO of the Nuclear Industry Association and former Labour shadow minister for energy. He said that nuclear power can provide a large amount of zero-emissions electricity from a relatively small geographic footprint over a long period of times.

The date of Hinkley’s start-up has been repeatedly delayed, and the costs have risen from an initial estimate of £20billion. The latest delay was announced in January and blamed Covid for delaying construction and rising energy and material costs due to the Ukraine conflict.

EDF criticized British regulators as well for requiring 7,000 design changes in its reactors that were not necessary in other countries. The fish return pipe is one of the changes. Hinkley also has to have a “offline” backup system for its critical systems in order to protect against cyberattacks.

Some industry sources disagree and say that EDF is to blame. One senior official said that EDF had not done the right engineering design and construction plan before they began work.

EDF’s leadership, as is understandable, strikes a defensive note. Tamer Al-Bishawi said, “We are doing many things for the very first time.” He said that EDF had to restart its supply chain and train tens of thousands of employees. “We are building the capability to allow Britain to build new nuclear power plants.”

You can walk around Hinkley to see where some of the £46 billion went. The site has been designed as a town with roundabouts, traffic lights, and roads. The office buildings are huge and sprawling, with giant canteens or convenience stores.

A 500-bed university-style campus is located on the edge of site, and the central lodge has food, two bars, and a fitness center. All of this is part of a massive logistical operation to bring 12,000 workers daily to the site in an area without large towns or infrastructure.

Stuart Crooks is the managing director of Hinkley Point C. He said, “I find the sheer logistics of operating the site on top of local constraints a major challenge.”

EDF believes that one of the largest bus stations in the UK is located at the heart of Hinkley. The site is 176 hectares in size, which is equivalent to about 250 football fields.

Stuart Crooks (Managing Director of Hinkley Point C) claims that the Environment Agency is responsible for some delays in the project.

Hinkley is a city where you can walk miles on a footpath that rises and falls randomly, makes sharp turns around cranes in use, and crosses busy intersections with loaders trundling past.

Each fiefdom is controlled by a different contractor. To enter a new area, you need to swipe a card through the metal turnstiles. It’s like entering a soccer field. Sometimes the ground drops away from you, creating a huge chasm filled with mucky water or fresh concrete.

The slogans on the lanyards of workers indicate their role in the project or sound strangely communist, like “Humility” or “Making an impact”.

Hinkley’s Crooks attributes some of the delays to the Environment Agency’s strict measures. “The processes at the agency are extremely, very, challenging and long.” “Everything is open to legal challenges, which go on forever,” he said.

EDF and the agency are currently at odds over the company’s plans to remove underwater speakers designed to discourage fish from swimming close to the site. The two parties agree that these underwater speakers will not work. However, they disagree on what EDF should instead do. Hinkley will not be able to operate until the dispute is resolved.

It is important to fix these issues because EDF intends to copy Hinkley’s design for Sizewell. It claims that the project will benefit from lessons learned at Hinkley. Crooks stated: “I am highly confident Sizewell is going to be faster and cheaper than this project.”

Sizewell is still being supported by the UK government. A final investment decision, which was supposed to be made before the elections but never happened, has not been reached. Ed Miliband, the energy secretary, has put this project at the top his list. The project is likely to be closely scrutinized by Ed Miliband, since electricity bill payers will bear the majority of the costs.

Miliband will also have to decide on how much money the UK is willing to spend for a smaller breed of modular reactors.

When completed, this site will supply electricity to 6 million homes. The view is not pleasant for now

Steve Thomas, professor emeritus of energy policy at Greenwich University notes that the reactor used at Hinkley is a model that has encountered problems and caused delays in China, Finland, and France. He said that pursuing Sizewell C was a risky and expensive venture, and would divert resources from options which would help us achieve our climate change goals faster, cheaper and more reliably.

Even more immediate concerns exist. CGN refuses to invest any additional money in Hinkley for the cost overruns. EDF will not give a specific number but, according to industry sources, the project faces a funding gap up to £5billion. Crooks said that they were actively seeking investors to help reduce the cash requirements. According to the contract, EDF, or more specifically, the French government, will be responsible for the bill.

The power station, when completed, will consist of two towering concrete buildings: unit one and two. Huge dome-shaped roofing will cover the reactors beneath. Last December, the 47m-wide unit one dome was winched in place over an hour and a half. It was a breeze compared to the two-and-a half day crane operation that will be required to install the reactor later in the year. The 500-ton, 30m high, torpedo shaped heart of this power station, which is 30m tall, will be lifted into the reactor hall through a giant opening, tilted at 90 degrees, and then lowered in the gap. It will remain there for the 60 years of operation of the station.

The reactor building has a maze of passageways, stairs and scaffolding. It’s a maze of narrow passageways and gantries, with plastic squares nailed to the floor that warn of “gaps beneath”.

The brick-lined cradle that would be used to catch a molten nuclear core in case of a meltdown is visible from the middle of the structure.

Matt Abbott, supervisor of the reactor hall, said: “We had a brickie team in there — 16 000 bricks.” “They had to do it all by hand.”

The care and attention that was lavished upon Hinkley Point C is evident once more. It’s a shame that the brickies’ work will be hidden, but we hope they are appreciated.