The UK and US are set to sign an agreement focused on accelerating the development of nuclear power.

The agreement aims to generate thousands of jobs and strengthen Britain’s energy security.

It is expected to be signed off during US President Donald Trump’s state visit this week, with both sides hoping it will unlock billions in private investment.

However, the designs behind some of the deals are relatively new and it could take many years before the nuclear projects generate energy for homes and businesses.

The key focus of the so-called Atlantic Partnership for Advanced Nuclear Energy is to make it quicker for companies to build new nuclear power stations in both the UK and the US.

The hope is to halve the time it takes to gain regulatory approval for nuclear projects from up to four years to two.

In practice, it means that if a reactor has already passed safety checks in one country, that work can be used to support the work of the other.

The UK’s nuclear programme already includes plans for small modular reactors (SMRs), which are a scaled-down version of larger plants. Britain’s engineering firm Rolls Royce has been selected to design and build the first in the country.

One of the commercial deals set to be signed this week is with US nuclear group X-Energy and the UK’s Centrica, which owns British Gas, to build up to 12 advanced modular reactors (AMRs) in Hartlepool.

Unlike SMRs, which are water-cooled nuclear reactors, advanced modular reactors use gases such as helium as a coolant.

There are very few AMRs in the world operating on a commercial basis such as China’s HTR-PM reactor.

X-Energy wants to build one in the US but, after announcing a partnership with US chemicals and plastics giant Dow in 2021, it has taken until March this year to submit a construction permit application to the Nuclear Regulatory Commission for the project in Texas.

X-Energy has said it hopes the reactor at a Dow site could be a blueprint for others and “manufacturers worldwide could replicate this model”.

The government said the Hartlepool deal has the potential to power 1.5 million homes and create up to 2,500 jobs.

Energy Secretary Ed Miliband said: “Nuclear will power our homes with clean, homegrown energy and the private sector is building it in Britain, delivering growth and well-paid, skilled jobs for working people.”

But Greenpeace questioned the UK’s focus on nuclear power.

“If these proposals for new reactors scattered around Britain really materialise, the net effect will be higher bills from nuclear’s relentlessly spiralling costs, and more CO2 as we wait for the builders to overcome their inevitable construction delays,” said Dr Douglas Parr, chief scientist for Greenpeace UK.

The cost of building large nuclear plants in the UK, such as Sizewell C in Suffolk, has jumped to £38bn from a previous estimate of £20bn. Centrica is one of the key investors in Sizewell C.

SMRs work on the same principle as large reactors, using a nuclear reaction to generate heat that produces electricity, but have around a third of the generating output.

The modular element means they could be built to order in factories – as a kit of parts – then transported and fitted together, like a flat-packed power station.

However, the SMR industry is still young, and many different designs are being investigated.

Centrica’s chief executive Chris O’Shea told the BBC’s Today programme that increased costs and delays “can happen in all large projects”.

But he said: “What you need to do is you need to do more than just one every 20 years in order to get better. So, the more you practice, the better you get which is why small and advanced modular reactors are particularly interesting because they’ll be repetitive so you’ll produce the same thing over and over again.

“That should bring improvements both in terms of cost and schedule and reliability and cost as well.”

Prime Minister Sir Keir Starmer has previously said he wants the UK to return to being “one of the world leaders on nuclear”.

In the 1990s, nuclear power generated about 25% of the UK’s electricity but that figure has fallen to around 15%, with no new power stations built since then and many of the country’s ageing reactors due to be decommissioned over the next decade.

In November 2024, the UK and 30 other countries signed a global pledge to triple their nuclear capacity by 2050.