UK's first small nuclear power station to be built in north Wales

This comprehensive report analyses the UK government's landmark November 2025 announcement to build the country's first Small Modular Reactors at Wylfa, Wales, representing a £2.5 billion investment in nuclear technology. The report examines the technical specifications of the Rolls-Royce SMR design, economic implications, including job creation and cost competitiveness, environmental considerations, including carbon emissions and nuclear waste, and the strategic context within UK energy policy. It provides balanced perspectives from government officials, environmental organisations, trade unions, local communities, and international stakeholders, while evaluating the opportunities and challenges of this first-of-a-kind SMR deployment. Readers will understand the complex trade-offs between nuclear and renewable alternatives, the regulatory pathway ahead, and what this decision means for Britain's energy transition, industrial capability, and climate goals through 2050 and beyond.

1. The UK government announced £2.5 billion investment for three Rolls-Royce SMRs at Wylfa, Anglesey, capable of powering 3 million homes from the mid-2030s, with potential expansion to eight units representing 30% of Great British Energy's total budget
2. The 470 MW Rolls-Royce SMR design uses unique boron-free chemistry and 90% factory-built modular construction, aiming to reduce build time and cost compared to traditional nuclear plants, though it remains unproven at commercial scale
3. Employment projections include 3,000 jobs during peak construction and hundreds of long-term operational roles, but concerns exist about whether jobs will benefit local Welsh workers or concentrate in English manufacturing facilities
4. The project faces immediate diplomatic tension with the US, whose ambassador expressed 'extreme disappointment' after advocating for American Westinghouse technology instead of the British SMR design
5. Environmental implications are contested: the project offers 60+ years of low-carbon electricity generation but creates 855 cubic metres of nuclear waste requiring isolation for hundreds of thousands of years, with no operational UK disposal facility
6. Cost competitiveness remains uncertain, with SMR levelized costs projected at $50-100/MWh compared to £40-50/MWh for offshore wind, though nuclear provides reliable baseload power without intermittency challenges
7. Regulatory approval depends on completing Generic Design Assessment by the end of 2026 and subsequent site-specific licensing, with any delays cascading through the entire project timeline to mid-2030s power generation
8. The project represents first-of-a-kind technology risks, including unproven manufacturing processes, supply chain development challenges, and potential cost overruns that have plagued historical nuclear projects like Hinkley Point C
9. Local community support is conditional on tangible economic benefits for Anglesey, with scepticism based on the 2020 cancellation of the previous Wylfa Newydd project by Hitachi and concerns about benefit distribution
10. Success could position the UK as a global SMR leader with substantial export opportunities in a projected £500 billion market by 2050, while failure would likely end UK SMR ambitions and reinforce infrastructure delivery challenges

On November 13, 2025, the UK government announced a landmark decision to build the country's first Small Modular Reactors (SMRs) at Wylfa on the island of Anglesey in North Wales. This £2.5 billion investment represents a significant pivot in British nuclear policy and marks, as Prime Minister Sir Keir Starmer described, the beginning of a "golden age" of nuclear power in the UK. [1] The project, led by publicly owned Great British Energy-Nuclear and designed by Rolls-Royce SMR, aims to deploy three initial reactor units, with potential expansion to eight, generating enough electricity to power approximately three million homes from the mid-2030s onward. [2]

The Wylfa announcement carries particular significance given the site's troubled recent history. After the closure of the original Magnox reactor in 2015, hopes for a new nuclear facility were dashed when Japanese company Hitachi abandoned the Wylfa Newydd project in 2020. [2] The selection of SMR technology over traditional large-scale reactors represents a strategic shift, prioritising modular, factory-built designs that promise faster construction timelines and reduced financial risk compared to conventional gigawatt-scale plants that have plagued the UK nuclear sector with delays and cost overruns.

However, the announcement has generated immediate controversy and raised critical questions about environmental impact, economic viability, and the role of nuclear power in the UK's energy transition. The US Ambassador, Warren Stephens, expressed "extreme disappointment" with the decision, having advocated for a large-scale plant powered by American Westinghouse technology. [3] Environmental organisations have long questioned the necessity and sustainability of nuclear expansion, while trade unions have raised concerns about whether the SMR approach will maximise job creation for British workers. [3]

This report provides a comprehensive analysis of the Wylfa SMR project, examining its technical specifications, economic implications, environmental considerations, and strategic context within UK energy policy. Drawing on official government documents, technical assessments, stakeholder responses, and independent analyses, it evaluates both the opportunities and challenges presented by this first-of-its-kind deployment of SMR technology in the United Kingdom.

The November 13, 2025 Announcement: Breaking News Analysis

Key Points

The UK government's announcement of the Wylfa SMR project represents a major policy commitment backed by £2.5 billion in public investment, with Rolls-Royce SMR selected as the technology provider. The project aims to deploy three initial reactor units, with the potential to expand to eight. However, it faces immediate diplomatic tensions with the United States and scepticism from some labour unions about its job-creation potential.

Official Government Position and Key Figures

The announcement was made jointly by the Department for Energy Security and Net Zero and Great British Energy-Nuclear, with Prime Minister Sir Keir Starmer personally championing the project during a visit to Anglesey. According to the official press release, "North Wales will become a beacon in the 'golden age' of nuclear, delivering the UK's first ever small modular nuclear reactors built by publicly-owned Great British Energy-Nuclear and, subject to final contract, designed by Britain's Rolls-Royce SMR." [1]

Energy Secretary Ed Miliband emphasised the project's significance for British industrial capability, stating: "This landmark investment proves Britain can still build big projects that stand the test of time. A generation of young people across North Wales will benefit from the good jobs, homes across Britain will get clean power, and we will take a big step forward in meeting our ambition to create a network of small modular reactors across the UK." [4]

The government's commitment includes an initial £2.5 billion investment, split between funding the development of the SMR design and securing all necessary planning consents and environmental permissions for the site. [12] Importantly, this funding comes entirely from Great British Energy's £8.3 billion budget, representing 30% of the organisation's total allocation—a detail that has raised questions about the original mission of GB Energy as primarily a renewable energy investment vehicle. [39]

Technology Selection and Rolls-Royce SMR

Rolls-Royce SMR was selected as the preferred technology partner following a competitive process. Chris Cholerton, Chief Executive of Rolls-Royce SMR, welcomed the decision: "We are honoured to have the opportunity to establish our UK fleet programme with an initial three units at the Wylfa site. Today's announcement marks the first step in what will be a 100-year commitment to clean energy, innovation, and community partnership at Wylfa." [4]

The Rolls-Royce SMR design is a 470 megawatt pressurised water reactor, significantly larger than many competing SMR designs but still much smaller than traditional gigawatt-scale plants. [7] Each reactor is designed to power approximately one million homes for over 60 years. [4] The technology represents "the UK's first domestic nuclear technology in more than 20 years," positioning it as both a national capability and potential export product. [8]

Rolls-Royce SMR is owned by a consortium that includes Qatar's sovereign wealth fund, France's BNF Resources, US energy company Constellation, and Czech utility CEZ. [3] The company has received both private investment (£280 million) and government grant funding (£210 million) to date. [8]

Immediate Stakeholder Reactions

The announcement generated swift and varied responses from stakeholders across the political, industrial, and environmental spectrum.

United States Diplomatic Response: Perhaps the most notable immediate reaction came from US Ambassador Warren Stephens, who published a statement saying he was "extremely disappointed" with the decision. The ambassador had urged ministers to commit to a large-scale plant, with US firm Westinghouse having reportedly presented plans for a new gigawatt station at the site. [2] A Downing Street spokesman responded: "It's totally legitimate for the US to say they wanted a US company there. We decided that this site should be for our own sovereign capability, for our flagship programmes, for Rolls-Royce." [13]

"Building three smaller reactors rather than one larger one at Wylfa would be a mistake because it would not maximise the number of jobs for British workers."

Trade Union Concerns: Sharon Graham, general secretary of Unite, criticised the plan, arguing that "building three smaller reactors rather than one larger one at Wylfa would be a mistake because it would not maximise the number of jobs for British workers." [3] This concern reflects broader questions about whether the modular, factory-built approach of SMRs—while potentially reducing construction time and cost—might also reduce on-site employment compared to traditional nuclear construction.

Local Political Support: Local representatives expressed cautious optimism. Rhun ap Iorwerth and Llinos Medi, local politicians from Anglesey, emphasised the need for tangible local community benefits. [21] Llinos Medi, the local MP, noted the history of previous failed nuclear announcements at the site, cautioning that "past announcements have not always led to actual implementation." [30]

Welsh Government Position: First Minister Eluned Morgan stated: "This is the moment Ynys Môn and the whole of Wales has been waiting for. New nuclear is a step into the future with secure jobs and secure energy guaranteed for the next generation." [21] The Welsh Government's support reflects the strategic importance of the project for North Wales' economy, particularly given that 35% of North Anglesey's population was previously employed at the original Wylfa nuclear power station. [6]

Timeline and Implementation Phases

According to the Department for Energy Security and Net Zero, Great British Energy-Nuclear will begin activity on the site in 2026, with an initial project for three reactors. [15] The reactors are expected to start supplying power to the grid from the mid-2030s. [1] Work on site preparation could start as early as next year, with power generation potentially beginning in the mid-2030s. [12]

The project timeline includes several critical regulatory milestones. The Rolls-Royce SMR design is currently undergoing Generic Design Assessment (GDA) with the Office for Nuclear Regulation, Environment Agency, and Natural Resources Wales. Step 2 of the GDA was completed in July 2024, with no fundamental environmental protection shortfalls identified. [7] The full GDA process is planned to last 4 years and 9 months, with completion expected towards the end of 2026. [7] A final investment decision is expected in 2029. [11]

The site could potentially host up to eight SMR units in total, though the initial deployment focuses on three reactors. [1] This phased approach allows for learning from early units while maintaining flexibility for expansion based on performance and demand.

Technical Specifications and Design Analysis

Key Points

The Rolls-Royce SMR represents a novel approach to nuclear power generation, utilising a 470 MW pressurised water reactor design with unique boron-free chemistry and extensive factory modularisation. While offering potential advantages in construction speed and safety, the technology remains unproven at commercial scale and faces questions about waste generation and long-term performance.

Core Reactor Design and Power Output

The Rolls-Royce SMR is a pressurised water reactor (PWR) design capable of generating 470 megawatts of electricity—enough to power approximately one million homes. [7] This capacity is notably larger than many competing SMR designs, which typically range below 300 MW, but remains substantially smaller than traditional large-scale reactors like Sizewell C (3.2 GW) or Hinkley Point C (3.2 GW). [38]

According to Rolls-Royce technical documentation, "The Rolls-Royce SMR power station will have the capacity to generate up to 470MWe of low carbon energy, equivalent to more than 150 onshore wind turbines and enough to power a million homes for 60 years." [10] The design uses a 3-loop PWR configuration and is designed to operate for at least 60 years with an expected capacity factor of over 95%. [23]

Unique Boron-Free Chemistry

One of the most distinctive features of the Rolls-Royce SMR design is its boron-free primary coolant chemistry. As the Environment Agency's assessment notes: "The Rolls-Royce SMR is being designed to operate without soluble boron (as boric acid) in the primary circuit during normal operations. Rolls-Royce SMR Limited noted removing the requirement for soluble boron for reactivity control means that the primary coolant pH can be controlled by a strong base only." [9]

This design choice uses potassium hydroxide (KOH) instead of the traditional lithium hydroxide and boric acid combination found in most PWRs. The boron-free approach offers several potential advantages: "Unlike other PWRs, the Rolls-Royce SMR does not use boron for routine reactivity control, simplifying operations and reducing waste." [10]

However, this innovation also introduces trade-offs. The absence of dissolved boron means the reactor requires more control rods for reactivity management. As the Environment Agency assessment explains: "Rolls-Royce SMR Limited has identified that one of the advantages of control of reactivity using dissolved boron is a reduction in the number of control rods that are needed. Therefore, by implication, operations without dissolved boron will require more control rods." [9] This could potentially increase solid radioactive waste generation from spent control rods.

Modular Construction Methodology

The defining characteristic of SMRs is their modular, factory-built approach to construction. The Rolls-Royce design exemplifies this philosophy: "The whole power station is constructed using around 1,500 standard transportable modules manufactured and tested in off-site factories to minimise activity on site." [10]

According to the company, 90% of the SMR will be factory-built, "limiting on-site activity primarily to assembly of pre-fabricated, pre-tested, modules which significantly reduces project risk and has the potential to drastically shorten build schedules." [11] The modules measure approximately 16 metres by 4 metres and are designed to be transportable by standard logistics methods. [11]

Professor Simon Middleburgh, director of the Nuclear Futures Institute at Bangor University, described the construction approach in accessible terms: the SMRs would be "built in a modular manner in factories and shipped to the site to be put together a bit like an Ikea chair." [2]

This modularisation strategy aims to address one of the nuclear industry's most persistent challenges: construction delays and cost overruns. As the Environment Agency assessment notes: "The modularisation construction approach may help to reduce the environmental impact of on-site construction and contribute to the sustainability of the design, by a quicker build and shorter period of construction." [9]

Rolls-Royce has established a Module Development Facility within the University of Sheffield's Advanced Manufacturing Research Centre to manufacture and test prototype modules. [7] The initial phase of this facility is valued at £2.7 million, part of a wider £15 million investment aimed at de-risking the manufacturing process. [34]

Site Footprint and Physical Characteristics

One significant advantage of SMR technology is its compact physical footprint. Each Rolls-Royce SMR unit will occupy just 21,500 square metres (5.3 acres). [10] This is dramatically smaller than traditional nuclear power stations, which can require hundreds of acres for reactor buildings, cooling systems, and associated infrastructure.

The compact design offers several benefits for site selection and environmental impact. As Rolls-Royce documentation emphasises, the smaller footprint allows for deployment in locations where large-scale nuclear plants would be impractical, potentially including brownfield industrial sites or locations with limited available land. [23]

Safety Systems and Design Philosophy

The Rolls-Royce SMR incorporates both passive and active safety features designed to maintain reactor integrity during accident scenarios. Recent academic research on similar SMR designs demonstrates the potential safety advantages of these systems. A study on the Korean i-SMR design found that "SMRs feature passive safety systems that rely on natural forces like convection and gravity, eliminating the need for external power" and that "the i-SMR is designed to maintain reactor core integrity for 72 hours without operator intervention using only passive safety systems." [24]

While specific details of the Rolls-Royce SMR's passive safety systems are not fully disclosed in public documents, the design philosophy emphasises multiple layers of protection. The Environment Agency's Step 2 assessment concluded that "there were no identified fundamental environmental protection shortfalls in the design and that no significant issues have been identified so far that may prevent us from being able to issue a SoDA at the end of Step 3." [7]

The smaller size of SMRs inherently provides some safety advantages. As one analysis notes: "Their smaller size also allows for more efficient cooling, significantly lowering the risk of radioactive leakage during accidents, and enabling effective passive mitigation of most Design Basis Accidents." [24]

Fuel Specifications and Refueling

The Rolls-Royce SMR uses standard uranium dioxide fuel enriched to no greater than 4.95% Uranium-235. [10] This enrichment level is typical for commercial PWRs and falls well within established regulatory frameworks.

One advantage of SMR designs is extended refuelling intervals. According to industry analysis, "Most SMRs require refuelling every 3–7 years, compared to every 1–2 years for large reactors. Some designs promise up to 20 years of continuous operation without refuelling." [22] While specific refuelling intervals for the Rolls-Royce design are not publicly confirmed, the extended operational periods between refuelling outages could improve capacity factors and reduce operational complexity.

Nuclear Waste Generation

Nuclear waste management remains one of the most contentious aspects of any nuclear technology. The Rolls-Royce SMR generates approximately 285 cubic metres of spent nuclear fuel over its 60-year lifetime—"about the size of a tennis court." [10] The spent fuel contains more than 99% of the radioactivity generated by the reactor. [10]

However, the Environment Agency's assessment raises an important consideration: "NWS [Nuclear Waste Services] noted that the smaller size of the Rolls-Royce SMR fuel means that more spent fuel could be generated per unit of electricity output, potentially leading to more disposal containers. This highlights the need for more detailed assessment of spent fuel arisings at GDA Step 3." [9]

This observation suggests that while the absolute volume of waste per reactor may be smaller, the waste intensity per megawatt-hour of electricity generated could potentially be higher than for large reactors. This is a critical factor for evaluating the environmental impact of SMR deployment at scale.

Nuclear Waste Services has provided a preliminary positive view on the disposability of waste from the Rolls-Royce SMR, noting that "the design is based on well-established PWR technology." [9] The UK's long-term waste management strategy involves deep geological disposal, with the government pursuing a consent-based approach to site selection. [26]

Verification of Power Generation Claims

The government's claim that the Wylfa SMRs will "deliver power for the equivalent of around 3 million homes" requires careful examination. [1] With three initial 470 MW reactors, the total capacity would be approximately 1,410 MW (1.41 GW).

According to UK energy statistics, the average household electricity consumption in the UK is approximately 2,700-3,000 kWh per year. [22] Assuming a capacity factor of 95% (typical for well-operated nuclear plants), three 470 MW reactors would generate approximately:

1,410 MW × 0.95 capacity factor × 8,760 hours/year = 11,730,000 MWh/year

Dividing by average household consumption: 11,730,000 MWh ÷ 3 MWh per household = approximately 3,910,000 homes

This calculation suggests the "3 million homes" figure is conservative and achievable, assuming the reactors operate at expected capacity factors. The claim appears to be verified by the technical specifications and typical nuclear plant performance metrics.

Economic Analysis and Investment Structure

Key Points

The Wylfa SMR project involves complex financial arrangements with £2.5 billion in initial government investment, though total project costs remain uncertain. Job creation projections range from 3,000 during peak construction to hundreds of long-term operational roles, but questions persist about cost competitiveness with renewable alternatives and the distribution of economic benefits between local and national supply chains.

Investment Breakdown and Funding Sources

The UK government has committed £2.5 billion to the Wylfa SMR project, though the full scope and structure of this investment requires careful analysis. According to official statements, this funding "will be split between funding towards the development of the SMR design and getting all the planning consents and environmental permissions in place on the site." [12]

Critically, the entire £2.5 billion allocation comes from Great British Energy's £8.3 billion budget—representing 30% of GB Energy's total funding. [39] As The Guardian reported, this represents a significant shift in the organisation's mission: "GB Energy will be expanding into new and exciting areas later this year, say Labour insiders. We'll see what that brings. The company's core mission seems to be a work in progress." [39]

The £2.5 billion government commitment represents only a portion of the total project cost. While exact total project costs have not been officially disclosed, industry analysis suggests that SMR projects typically require substantially more than initial government seed funding. The government investment appears designed to de-risk the project and attract private sector co-investment, following the Regulated Asset Base (RAB) financing model that has been adopted for other UK nuclear projects like Sizewell C. 

Rolls-Royce SMR has already secured £280 million in private investment alongside £210 million in government grant funding for design development. [8] The company is owned by a consortium including Qatar's sovereign wealth fund, France's BNF Resources, US energy company Constellation, and Czech utility CEZ, suggesting potential for additional international investment. [3]

Total Project Cost Estimates

While official total project cost estimates for the Wylfa SMR deployment have not been publicly released, comparative analysis provides context. The cancelled Wylfa Newydd project, which would have used conventional large-scale reactor technology, was estimated at £12 billion for approximately 5.3 GW of capacity. [17]

Industry analysis suggests that SMRs aim for a levelized cost of electricity (LCOE) of approximately $50-100/MWh. [22] However, as one analysis notes: "The levelized cost of electricity (LCOE) for SMRs is about $50–$100/MWh. This is a bit higher than large reactors. However, SMRs are competitive because they can scale well and have lower financial risks." [22]

The challenge for first-of-a-kind (FOAK) SMR projects is that they typically face higher costs than subsequent units. As the World Nuclear Industry Status Report has documented, nuclear projects consistently face "budget overruns, construction delays, and reliability problems in the operational phase." [18] The modular approach aims to mitigate these risks, but the Wylfa project will be the first commercial deployment of Rolls-Royce SMR technology, inherently carrying FOAK risks.

Employment Projections and Analysis

The government has projected that the Wylfa SMR project will create "up to 3,000 jobs" during peak construction. [2] Prime Minister Starmer suggested the total could be even higher when combined with the associated AI growth zone: "Putting that together, 6,500 jobs. I personally think it'll be more than that, because I do think these things have a magnet effect. They draw in other businesses." [14]

However, these figures require careful disaggregation:

Construction Phase Employment: The 3,000 jobs figure represents peak construction employment, which will be temporary and likely last several years during the build phase. Historical nuclear projects suggest construction employment is highly variable, ramping up during major construction activities and declining as projects near completion. [5]

Operational Phase Employment: The government states there will be "many hundreds" of long-term operational roles once the reactors are operational. [12] This is substantially fewer than the construction phase employment, though these jobs would be sustained for the 60+ year operational life of the reactors.

Direct vs. Indirect Employment: The Rolls-Royce SMR corporate materials claim the project "is expected to support an average of almost 8,000 highly skilled jobs across the UK per year during the build programme." [4] This figure appears to include indirect employment in the supply chain, which is substantially larger than direct on-site employment.

Skills Requirements and Training: Local educational institutions are positioning themselves to support workforce development. Dr Siôn Peters-Flynn, Principal of Coleg Menai, emphasised: "Key to the success of the Wylfa SMRs will be the contribution of the regional workforce. A central component of this project must be a substantial, sustained commitment to the education and training of local people, in particular local young people." [13]

Geographic Distribution Concerns: A significant concern raised in public commentary is whether jobs will actually benefit local residents. As one analysis noted, "There are significant concerns about job allocation, with some commenters worried that most skilled jobs will go to non-local workers." [21] Additionally, "The SMR modules will likely be manufactured in England (Sheffield and Cumbria), not locally in Wales." [21]

This geographic distribution of manufacturing employment represents a critical tension in the project's economic impact. While the government aims for "70% of SMR supply chain products to be British-built," the concentration of manufacturing in England rather than Wales may limit direct local economic benefits for Anglesey. [37]