Source: United Kingdom – Executive Government & Departments

June 10, 2025

Scientists comment on news that the UK government is investing in a nuclear plant at the Sizewell C site and a small modular reactor programme. 

Prof Patrick Regan, Professor of Nuclear Metrology, University of Surrey, said:

“The announcement that the UK government has committed £14.2bn of investment to build European Pressurized Reactors (EPRs) at the Sizewell C site will contribute to the UK tackling the delicate balance between ever-increasing secure energy requirements and our commitment to achieving net-zero. The EPRs planned at Sizewell C represent Generation 3+ technology and build on more than 70 years of operational reactor experience worldwide to provide the cleanest, safest and most efficient form of nuclear power yet.

“This large investment, however, brings with it the obvious need to produce and maintain a highly skilled, expert workforce related to all phases of the Sizewell C project. Science and Engineering Apprentice, Graduate and Post-Graduate training in areas such as chemical engineering, material science, nuclear physics & radiochemistry, environmental monitoring,  radiation measurement and health physics will be key in enabling ‘life-long’ UK-based careers in this industry, in line with such a far horizon project. This is a long-term investment in the UK’s national infrastructure, and it needs a skilled workforce to ensure its ultimate success.”

Dr Phil Johnstone, Principal Research Fellow, University of Sussex Science Policy Research Unit, Patron of Nuclear Information Service, Member of Sussex Energy Group, and Member of Nuclear Consultation Group:

Is this a good move? 

“The decision on Sizewell C is a bad move. It will likely lead to increasing costs for UK electricity consumers and represents a significantly slower means of combatting climate change than alternative options. The announcement comes alongside the decision to select submarine reactor manufacturer Rolls Royce as the winning bidder to develop Small Modular Reactors. These are part of the same underlying goal: to sustain the UK military nuclear industrial base via subsidies from civil nuclear power, with democratic scrutiny of this strategy almost entirely absent.”

Prof Andy Stirling, professor of science and technology policy at the University of Sussex Science Policy Research Unit:

Is this a good move (or not) when it comes to energy and fossil fuels?

“It is well acknowledged behind the scenes (but denied in public), that this move is more intended to support the kind of nuclear industrial base needed for military than for climate reasons. Nuclear power stations like Sizewell C are so slow and expensive compared to renewables and storage strategies, that they erode rather than enhance climate action.”

What does this mean for UK energy production?  Is there overspeculation?

“This will make UK energy production needlessly more expensive, less secure and less effective in climate terms, than if the same money had been spent on renewables and energy storage.”

What does the science say?

“On this as on many other policy issues, what counts as ‘the science’ is more uncertain and context-dependent than any side typically implies. If either nuclear advocates or critics claim their arguments to be uniquely or unequivocally science-based then that is a sign that they are seeking to mislead.”

Dr Sarah Darby, Emerita Research Fellow, Energy Programme, Environmental Change Institute, University of Oxford, said:

“The argument that building Sizewell C will be markedly cheaper and quicker than Hinkley C is weak. Hinkley C is ‘first of a kind’ in the UK but has the same design as Olkiluoto in Finland and Flamanville in France. These two have been, respectively, over 10 years late and almost four times over budget [1] and over 12 years late and over four times over budget in real terms [2,3]. Neither is yet working reliably [4,5].

“The unfinished Hinkley C was reported by EdF last year as already 90% over budget and 7 years late – and EdF do not expect it to be finished before 2029-31.

“In the light of these figures from three power plants of the same design as SZC, Ed Miliband’s forecast of a 10-year build time looks wildly optimistic. Where cost and complexity are concerned, there is the additional concern about the SZC site being on a flood-prone and eroding coastline, with sea levels on the rise.

“EdF are now wholly owned by the French government, following their extreme financial difficulties, and it is unclear whether they will take any stake at all in SZC. This is hardly a vote of confidence in the prospects of their own design.

“The argument that nuclear build helps with climate goals is similarly weak. New nuclear would arrive too late to assist – renewables already supply over half of UK generation [6] –  and are on the rise. The massive sums involved are money not spent on quicker and more effective moves towards energy transition. Bloomberg NEF’s latest assessment of energy transition investment trends* refers to renewables, energy storage, electric vehicles, and power grids as ‘proven, commercially scalable [and with] established business models’, yet categorises nuclear power as an ‘emerging’ technology, with investment held back by lack of affordability and technology maturity [7].

“Nuclear is being presented by the Government as complementary to renewables, for ‘when the sun doesn’t shine and the wind doesn’t blow’. But what we need for these times – and for times of abundant renewable supply – is flexibility from storage and demand-side response, not large-scale inflexible power plants that cannot easily be turned down or up and that can be shut down at a moment’s notice [5,8].

“As so often, the debate is focused on supply rather than demand – what we use energy for. The government are citing figures of a doubling of demand by 2050 that are certainly not set in stone and likely to be exaggerated. AI demands are the new kid on the block but, as DeepSeek has shown, they need not be nearly as high as is often made out. There is still plenty of scope to improve energy security through energy efficiency, allied with storage and demand-side response, without compromising quality of life [9].

“Successive governments have already sunk £6.4bn of taxpayers’ money into Sizewell C, but this is no reason to compound the error. A further £14.2bn is substantial but falls a long way short of the £40bn ‘overnight’ cost estimated by the FT [10]. Further, this £40bn estimate does not take into account the costs of capital, decommissioning and disposal of waste. The last of these is itself a topic of major concern to the Public Accounts Committee [11].

“It is not too late to avoid a FID for Sizewell C and to steer funding in more productive directions, including modernisation of the electricity grid, energy efficient buildings and transport systems, and storage. Such investment could create jobs and improve living conditions around the country.”

References

1 – https://reneweconomy.com.au/big-batteries-and-evs-to-the-rescue-again-as-faults-with-new-nuclear-plant-cause-chaos-on-nordic-grids/

2 – https://www.thetimes.com/world/europe/article/delays-debts-and-false-promises-inside-frances-nuclear-nightmare-h2wpfhx0w

3 – https://www.edf.fr/sites/groupe/files/2023-04/edf-urd-annual-financial-report-2022-en.pdf

4 – https://www.reuters.com/business/energy/newest-french-reactor-faces-further-delays-due-new-issues-2025-04-11/

5 – https://eandt.theiet.org/2025/03/12/radioactive-coolant-leak-europes-largest-nuclear-reactor

6 – https://www.gov.uk/government/statistics/total-energy-section-1-energy-trends

7 – https://about.bnef.com/insights/finance/global-investment-in-the-energy-transition-exceeded-2-trillion-for-the-first-time-in-2024-according-to-bloombergnef-report/

8 – https://royalsocietypublishing.org/doi/full/10.1098/rsta.2016.0462

9 – https://www.creds.ac.uk/publications/strategy-and-policy-statement-for-energy-policy-in-great-britain-creds-response/

10 – https://www.ft.com/content/0b483728-de5b-4f2e-8d00-c49885c572c9)

11 – https://committees.parliament.uk/committee/127/public-accounts-committee/news/207132/sellafields-race-against-time-nuclear-waste-cleanup-not-going-quickly-enough-pac-warns/

Stephanie Baxter, Head of Policy, Institution of Engineering and Technology, said:

“The £14.2 billion of funding announced today for the development of Sizewell C, alongside selecting Rolls-Royce SMR as the preferred bidder to develop the UK’s first small modular reactors, marks an important step forward towards nuclear playing a significant role in the UK’s energy mix.

“Nuclear infrastructure, both large and small, will be needed in our energy system if the UK is to have a secure, affordable and sustainable energy system for 2030 and beyond. However, the Government must also take a whole system view of the wider energy system to ensure new nuclear infrastructure compliments other energy generation and distribution resources currently deployed and being developed.

“Significant infrastructure projects such as these rely on long-term stability – in the supply chain, regulations and the skills pipeline. That is why today’s announcements must be backed up by clear plans for delivery, including engagement with local communities.

“These ambitions will also not be met without the skilled engineering and technician workforce that will be critical to delivering and maintaining new nuclear infrastructure.

“Great British Energy must work closely with Skills England to ensure that these plans are backed by a long-term workforce strategy to deliver skilled job opportunities across the country – both by training up new workers in schools and colleges, and upskilling/reskilling the existing workforce through flexible funding in the Growth and Skills Levy.”

Will Davis, Nuclear Expert and a Member of the Institution of Engineering and Technology’s Sustainability and Net Zero Policy Centre, said:

“Today’s announcements are a clear demonstration of the government’s long-term commitment to low-carbon energy security, extending beyond the 2030 clean power target and taking concrete steps toward achieving net zero by 2050.

“To meet our net zero ambitions, we must significantly scale up electricity generation – by two to three times current levels – and this will only be possible through large-scale projects like Sizewell C and the Small Modular Reactor (SMR) programme.

“While these developments are both welcome and necessary, the UK nuclear industry must address its ongoing credibility challenges around delivering projects on time and within budget. Unlike the UK’s Hinkley Point C, nuclear projects in countries like China and the UAE have avoided major delays. Learning from these international examples is essential if we are to attract private investment and reduce reliance on gas-fired power stations.

“The selection of a preferred bidder for the SMR fleet is a long-awaited milestone – over a decade in the making – and we’re pleased to see it finally progressing.

“The clarification of roles between Great British Energy and Great British Energy – Nuclear, with NESO overseeing the critical upgrades to our national electricity infrastructure is welcomed. These upgrades are vital and must be properly funded, not treated as an afterthought.

“With the announcements on Sizewell C and SMRs, we urge the government to clarify its position on future gigawatt-scale nuclear projects, such as the previously proposed development at Wylfa.

“New nuclear power stations require a high-tech supply chain and a highly skilled workforce. Investment in key manufacturers like Sheffield Forgemasters is encouraging, but broader supply chain investment hinges on project certainty – contracts must be signed.

“The IET continues to support the sector through initiatives like the Nuclear Skills Taskforce. We’re also pleased to see continued investment in STEP, the UK’s prototype fusion power plant. A £2.5 billion commitment is significant and deserves more visibility.

“However, we note the absence of updates on advanced nuclear technologies, which could play a crucial role in decarbonising hard-to-abate sectors such as steelmaking and hydrogen production. We hope to see further clarity on this soon.”

Dr Lewis Blackburn, Lecturer in Nuclear Materials, University of Sheffield, said: 

“Today the UK government demonstrated a clear and renewed commitment to nuclear fission as a means to achieve Net Zero, a key goal that was outlined in the 2024 White Paper “Civil Nuclear: Roadmap to 2050”. This comes in the form of an approximately £14B commitment to the Sizewell C project, comprising two EPR (European Pressurised Reactors) delivering a total of 3.2 GWe. The project is forecast to support 70k jobs and produce enough energy to power 6M UK homes. Today’s news also comes alongside an announcement that Rolls-Royce have been identified as the preferred bidder to construct the UK’s first Small Modular Reactors (SMR) – a fleet of smaller fission reactors designed to be built ‘modular’ on a production line, prior to shipping and assembly on-site. 

“The UK faces a potential skills challenge in the field of nuclear engineering and projects like Sizewell C and Rolls-Royce SMR offer an exciting opportunity to build a skills pipeline, increasing the number and diversity of people entering the nuclear workforce, and bolstering the supply chain.

“In order for the UK to maintain its international reputation as a leader in civil nuclear, it must continue to invest heavily in new infrastructure, the wider industrial supply chain and R&D. Thus, producing the next generation of nuclear expertise in both the industrial and academic sectors, equipping them with the skills required for the UK to continue to utilise nuclear fission, safely, for generations to come. 

“An important aspect of this is ensuring that highly radioactive waste, generated as a by-product of nuclear fission, is not passed onto future generations and is permanently disposed of. In this area, the UK is in the process of siting a geological disposal facility – a dedicated site wherein intermediate and high-level radioactive waste will be isolated from the wider environment permanently. The international consensus in the wider scientific and technical community is that this is the only feasible way to safely manage such wastes, ensuring passive safety. This is the focus of significant R&D in both the technical and academic space.”

Dr Mark Foreman, Associate professor of Nuclear Chemistry / Industrial Materials Recycling, Chalmers University of Technology, Sweden, said:

“Building a new power plant based on light water reactors at Sizewell is a good idea, it will provide a reliable supply of electric power which will help society reduce its dependency on fossil fuels. I hold the view that it will be a safe means of providing for the energy needs of society. Many critics of nuclear power use the example of the Chornobyl accident to argue that all nuclear power plants are unsafe. This is unreasonable, operating the Chornobyl reactor in the same way as it was just before the accident can be thought of as like roller blading along the M1. While running modern (or even a 1980s era) light water reactor is like calmly driving a Volvo equipped with all the latest safety features along the M1.”

Prof Robin Grimes FRS FREng, Professor of materials physics, Imperial College London, said:

“Large plants such as Hinckley, currently under construction and this announced plant at Sizewell are very good at providing constant base load electricity capacity. They are also good for supporting grid stability and providing inertia. Of course they offer generation diversity and energy security. They will offer these benefits for many decades. As we turn to more electricity use to reduce carbon emissions we will need more nuclear electrify. However, large plant are less good at helping with the inherent intermittency of renewables. For this we need the greater flexibility as provided by small modular reactors or the higher temperatures of advanced modular reactors which offer access to more technology options for decarbonisation. I therefore see this announcement as part of the systems approach by which we progress to greater energy security and decarbonisation.”

Prof David Armstrong, Professor of Materials Science and Engineering (Department of Materials), University of Oxford, said:

“This is excellent news for the UK energy landscape. As the UKs aging AGR fleet retires new baseload energy is required. Sizewell C will sit alongside Hinkley Point B to provide sustainable emission free baseload energy complementing the growing wind and solar power and making a significant contribution to UK energy security.”

Dr Iain Staffell, Associate Professor of Sustainable Energy at the Centre for Environmental Policy, Imperial College London, said:

“Today’s decision is an important one, but even with Hinkley C and Sizewell C, the UK’s nuclear capacity in the 2030s will still be below its 1990s peak.

“After a decade of dithering, Sizewell C is a litmus test of the UK’s ability to deliver complex infrastructure on schedule.

“This deal lives or dies on its delivery.  Sizewell C must be built on time and on budget, learning from the (many) mistakes from Hinkley Point C and other UK mega-projects.

“Nuclear power offers a strong energy security hedge.  Fuel and key parts can be stockpiled, insulating consumers from foreign instability and gas price spikes.

“Sizewell C won’t start generating for nearly a decade if it is built on time, so it only just contributes towards the Government’s 2035 clean-power goal.  But, it is building for the long-term, and will deliver carbon-free electricity well into the 2080s.

“People are rightly concerned by the environmental impacts and emissions from the enormous construction project, but compared to the scale of energy production over the next six decades, nuclear remains one of the cleanest power sources we have.

“The upfront cost is undoubtedly high.  £14 billion could fund around 10 GW of offshore wind versus just 3.2 GW of nuclear.  But, these reactors will run day and night, especially valuable when the wind is not blowing.”

Louis Barson, the Institute of Physics Director of Science, Innovation and Skills said:  

“It is good to see this decision made about developing Sizewell C. New nuclear will play a vital role in bringing reliable, secure and affordable power to new markets, decarbonising industry and helping countries meet their net zero commitments – as part of our future low-carbon energy mix.

“But we need to make sure we also pay attention to the desperate need for hundreds of thousands of skilled workers to support both this project and the development of smaller, modular, nuclear reactors. 

“Signing off on Sizewell C is only half the picture, we need the nuclear-ready scientific workforce to make it a reality: that means more physics teachers, well-funded physics departments in universities and a healthy pipeline of physics talent.” 

Tom Greatrex, Chief Executive, Nuclear Industry Association, said:

On Sizewell C Given Go-Ahead from Government

“This is a momentous day for Sizewell C and for the British nuclear programme. Sizewell C is one of Britain’s most important clean power projects, and will give the country the jobs, the economic growth and the energy security we need to ensure a secure and reliable power supply for the future. This record investment confirms the government is serious about building new nuclear and all the economic benefits that come with it, and will be welcomed in communities the length and breadth of Britain.”

On Rolls-Royce SMR Winning the UK SMR Competition

“This is a hugely significant moment for Rolls-Royce SMR and for the British nuclear programme. These SMRs will provide essential energy security and clean power alongside large scale reactors, all the while creating thousands of well-paid, skilled jobs, opportunities for growth right across the country and significant export potential. We look forward to working with Rolls-Royce SMR and all other potential SMR vendors, including those not successful today, on making Britain the best place to build new nuclear anywhere in the world.”

Prof Mark Wenman, Professor in Nuclear Materials, Imperial College London, said:

“This is a big step forward.  Since the 1990s the amount of nuclear energy the UK produces has been steadily declining from around 12 to 4.5 GWe today.  Sizewell C will help reverse this trend and  further provide the UK with energy security. It will help balance the grid with the increase of renewables, replace fossil fuel plants and protect us against potential blackouts, as recently seen in Spain.  Whilst the costs may seem high initially, this needs to be balanced against the fact that these reactors will produce low carbon electricity  for 80 or possibly 100 years, 24/7, providing around a tenth of the current  UK electricity needs.  Once paid for, nuclear reactors produce the cheapest  electricity of any kind, so this investment should be seen as future proofing the UK electricity system.”

Prof Adrian Bull, Chair in Nuclear Energy and Society, Dalton Nuclear Institute, University of Manchester, said:

“It’s very welcome news to see the announcements today of Government support for a new wave of nuclear power in this country.  We’ve known for decades that reliance on imported gas could ruin the environment – but recent years showed us that it can ruin the economy too.  Nuclear gives much-needed resilience against global fossil fuel prices, without emitting the gases that cause climate change, so it’s excellent news that we are going to see new plants – both large and small – built.

“I’m especially pleased that we have finally got over our national phobia of replicating a previous project.  We’ve never done that in our UK nuclear fleet before, but the rest of the world learned ages ago that series construction is the route to certainty over the time and budget for such projects.  Doing the same things at Sizewell which we have already done at Hinkley Point is much easier than starting from scratch to build a massively complex plant for the first time.

“The announcement of Rolls Royce as the winner of the SMR competition is a welcome sign of progress, but it’s disappointing to see only one winner selected, when we had all anticipated more.  Government has long been supporting the Rolls Royce SMR project – with over £200m of public funds provided already – so it was inconceivable they would not be on the podium at the end of the race.  Seeing them there alone makes the two years spent by Great British Nuclear on running a competition look like time and effort that could have been better spent.

“Overall though, these nuclear plants – whilst not cheap – will produce reliable, low carbon electricity around the clock and will most likely do so for the best part of a century.  This is an investment in our grandchildren’s future as well as helping towards our 2050 climate goal.”

Prof Dame Sue Ion GBE FREng FRS, a Fellow of the Royal Academy of Engineering, said:

“It’s really good news that the Government is finally taking steps to ensure that nuclear energy plays the vital role it should in achieving significant quantities of stable low carbon electricity.  Perhaps as importantly, if not more so, is the news that Rolls Royce’s Small Modular Reactor has been selected as the technology of choice to progress the opportunity presented by SMRs.  These systems are designed from the outset to be modular, with modern construction techniques using much more factory fabrication, so they will be faster and easier to build.”

Prof Tom Scott, Professor in Materials, University of Bristol, said:

“This is an extremely important strategic step for the UK towards achieving net zero carbon emissions.  Nuclear energy is a safe, secure and reliable form of electricity generation.  With the lessons learnt from the Hinkley Point C project, and with the experienced workforce and supply chain that has been established because of it, my expectations are high for the delivery of Sizewell C at a much lower cost and shorter timescale.

“The announcement about Government investment in Sizewell C and more excitingly, about the investment in Small Modular Reactors (SMRs), really shows the Government’s understanding and commitment towards nuclear as a key part of the solution towards achieving zero carbon emissions in the UK.

“SMRs offer the potential for providing new nuclear power stations much faster and more cheaply than conventional large-scale light water reactors like Hinkley Point C.  Ultimately, the roll-out of SMRs delivered by British companies like Rolls-Royce will help to keep our electricity prices low whilst also generating high-value jobs across the U.K.  This is a smart investment for the UK.”

Dr Mark Foreman, Associate professor of Nuclear Chemistry / Industrial Materials Recycling, Chalmers University of Technology, Sweden, said:

“Building a new power plant based on light water reactors at Sizewell is a good idea, it will provide a reliable supply of electric power which will help society reduce its dependency on fossil fuels.  I hold the view that it will be a safe means of providing for the energy needs of society.  Many critics of nuclear power use the example of the Chornobyl accident to argue that all nuclear power plants are unsafe.  This is unreasonable, operating the Chornobyl reactor in the same way as it was just before the accident can be thought of as like roller blading along the M1.  While running modern (or even a 1980s era) light water reactor is like calmly driving a Volvo equipped with all the latest safety features along the M1.”

**https://www.bbc.co.uk/news/articles/c4gr3nd5zy6o

Declared interests

Prof Adrian Bull: “I am a (paid) part time Professor at the Dalton Nuclear Institute, part of the University of Manchester; I am a (paid) consultant for US nuclear communications consultancy Full On Communications; I am an (unpaid) Board member of the Northern Nuclear Alliance; I am an (unpaid) Trustee of the Nuclear Institute; and am also the President-Elect, taking over in Jan 2026.”

Prof Dame Sue Ion: “Sue is Honorary President of the National Skills Academy for Nuclear.” “Sue is also a member of the Nuclear Regulatory Task Force.”

Prof Tom Scott: “In terms of interests, I am Director of the Spur West Nuclear Hub and Professor of Nuclear Materials at the University of Bristol sponsored by the Royal Academy of Engineering and the UK Atomic Energy Authority.

The nuclear hub is a consortium of academic, industrial and governmental partners coalescing around the requirement for research, skills and innovation in the UK nuclear sector.”

Dr Mark Foreman: “I have worked on advanced nuclear reprocessing for years and have also have worked on nuclear reactor safety issues.  I have done and supervised research on the chemistry of nuclear accidents.”

Prof Mark Wenman “I have previously received funding for research from EDF Energy, Rolls-Royce, the UK National Nuclear Lab”

Tom Greatrex “The NIA is funded by its 320 member companies from across the civil nuclear industry.”

Dr Iain Staffell “I receive industry funding from a several companies in the UK and European energy sector, I try to keep this balanced so as not to over-represent any one technology or organization.  Recent funding sources include: Drax, Octopus, SSE, HM Government, NESO (National Grid), EWE, Aurora, Baringa, Shell, Uniper, SLB, and the World Bank.”

Prof David Armstrong “I’ve had funding from UKAEA, Rolls Royce and EdF for research and students over the last 20 years.”

Prof Robin Grimes “I am a non-executive director of UKAEA and receive research funding from the UK national nuclear laboratory.”

Dr Mark Foreman “I do not currently get any money from the nuclear industry, I do not stand to make any money from the sales of nuclear products / technology. I have not been employed by the nuclear industry. I think that in terms of conflicts of interest I have none.”

Dr Lewis Blackburn “He receives funding from industry via Nuclear Decommissioning Authority, National Nuclear Laboratory, and Nuclear Waste Services”

Stephanie Baxter “No conflicts of interest.”

Will Davis “No conflicts of interest.”

Prof Andy Stirling “no conflicts of interest to declare.”

Dr Phil Johnstone “no conflicts of interest to declare.”

Dr Sarah Darby “I have no conflicts of interest to declare.”

For all other experts, no reply to our request for DOIs was received.