The Nuclear Fleet, from AGR Retirements to Wylfa SMR

Current Nuclear Fleet Position

Three commitments in the last twelve months have reshaped the new-build picture, and they sit front because every other paragraph below builds on top of them. The DESNZ written statement of 13 November 2025 set out the Wylfa site selection for three Rolls-Royce Small Modular Reactors, with a budget envelope of 2.5 billion pounds; the formal contract followed in April 2026, with Final Investment Decision expected in 2029 and in-service mid-2030s.⁶ The Sizewell C consortium reached Final Investment Decision on 22 July 2025 under the Nuclear Energy (Financing) Act 2022 Regulated Asset Base model, with 14.2 billion pounds of equity from the Crown, EDF, La Caisse de depot et placement du Quebec and Centrica, and 36.6 billion pounds of debt at financial close, against a headline capital estimate of 38 billion pounds in 2024 prices for the 3.2 gigawatt EPR pair. Hinkley Point C remained the only large reactor pair physically under construction, with EDF's reconfirmation in February 2026 pointing to first power on Unit 1 in 2030 and Unit 2 around 2032, against a nominal cost estimate of 46 to 47 billion pounds.

The operating fleet picture is different. Sizewell B (1.2 gigawatts, pressurised water reactor, in service since 1995) continues to run; the operator has a study under way against a possible licence extension to 2055, which would follow the international pressurised water template that has carried the United States and French fleets past forty years. The four Advanced Gas-cooled Reactor stations close inside a tight window after EDF's September 2025 lifetime review: Heysham 1 and Hartlepool target retirement in March 2028; Heysham 2 and Torness in March 2030. Hinkley Point B retired in 2022 and Hunterston B retired in 2022; Dungeness B has been defuelling since 2021. The system-level result is that firm nuclear capacity holds at about 6 gigawatts through early 2028, then steps down toward 1.2 gigawatts of Sizewell B alone by around 2030, and recovers as Hinkley Point C Unit 1 reaches first power on EDF's 2030 target.¹

The Connections Reform Gate 2 outcomes in April 2026 (283 gigawatts of generation and storage progressed to firm offers across Phase 1 to 2030 and Phase 2 to 2035) sit alongside the nuclear picture rather than inside it.⁵ The new-build nuclear pipeline sits outside the Capacity Market auction cycle because the procurement mechanism for a Final Investment Decision-stage large reactor is the Contract for Difference (for Hinkley Point C) or the Regulated Asset Base (for Sizewell C), and the procurement mechanism for the Wylfa Small Modular Reactor trio is the GBN site contract route. The relevant arithmetic for a planner reading the 2030 trajectory is: 1.2 gigawatts of Sizewell B firm into the late 2020s, plus the Hinkley Point C ramp from Unit 1 in 2030 to Unit 2 around 2032 (3.2 gigawatts when both units run), plus a single-digit percent of annual energy contribution from nuclear that holds the floor while the variable-renewable share lifts through the action plan window.

The operating fleet and the AGR retirement window

The operating fleet sits in one paragraph so the entire set is in view before the per-station detail. Great Britain runs five reactor units across five stations as of May 2026: one pressurised water reactor at Sizewell B (1.2 gigawatts, in service since 1995), and four Advanced Gas-cooled Reactor twin-reactor stations at Heysham 1, Hartlepool, Heysham 2 and Torness (combined 4.79 gigawatts). Sizewell B is the only commercial pressurised water reactor in the Great Britain fleet; the four Advanced Gas-cooled Reactor stations represent the second-generation domestic design that the Central Electricity Generating Board commissioned through the 1980s. Two further Advanced Gas-cooled Reactor stations have retired in the recent past: Hunterston B in January 2022 and Hinkley Point B in August 2022. One further station, Dungeness B, has been defuelling since June 2021 after the operator determined the safety case no longer supported a return to service. Hinkley Point A (Magnox, retired 2000) and Hunterston A (Magnox, retired 1990) sit in care and maintenance on the Nuclear Decommissioning Authority estate.

Why the Advanced Gas-cooled Reactor closures cluster across 2028 to 2030

The closure dates are set by the inspectable condition of the graphite core, not by a chosen retirement age. An Advanced Gas-cooled Reactor uses carbon dioxide gas as the coolant and graphite as the moderator. The graphite bricks that form the core sit inside a pre-stressed concrete pressure vessel at an outlet temperature of around 650 degrees Celsius, the design choice that gives the Advanced Gas-cooled Reactor its higher steam-cycle efficiency than a pressurised water reactor (the pressurised water reactor outlet is around 320 degrees Celsius). Over a working life of forty years and more, the graphite oxidises and the bricks shrink and crack on a measurable curve. The operator inspects the core through a sub-set of fuel channels on a scheduled cadence; the Office for Nuclear Regulation reviews the inspection record and the safety case. When the graphite condition reaches the limit set out in the site safety case, the station closes.

The Advanced Gas-cooled Reactor stations have run longer than the original Central Electricity Generating Board design life of thirty years. Hunterston B and Hinkley Point B ran from 1976 to 2022, forty-six years. Dungeness B ran from 1983 to 2021. Heysham 1 and Hartlepool have run from 1983 toward a March 2028 target, forty-five years. Heysham 2 and Torness have run from 1988 toward a March 2030 target, forty-two years. The cluster across 2028 to 2030 reflects the construction sequence of the 1980s; the graphite curves track the calendar back to the same period for the four remaining stations. Defuelling each Advanced Gas-cooled Reactor takes about six years after closure; care and maintenance under the Nuclear Decommissioning Authority follows for decades before the final demolition step.¹

The contractual picture sits underneath the table. Sizewell B operates under a station licence held by EDF Energy Nuclear Generation Limited. Hinkley Point C operates under a station licence held by NNB Generation Company (HPC) Limited, an EDF-led joint venture. Sizewell C operates under a station licence held by Sizewell C Limited, a joint venture among the Crown (through DESNZ), EDF, La Caisse de depot et placement du Quebec and Centrica. The Wylfa Small Modular Reactor site contract sits between DESNZ, Great British Nuclear and Rolls-Royce SMR Limited, with the licensee structure to be settled before Final Investment Decision in 2029. The Office for Nuclear Regulation holds each licence and judges each safety case on its own terms.

Hinkley Point C: the EPR pair in commissioning

Hinkley Point C is the first new nuclear station to enter the Great Britain build pipeline since Sizewell B reached first power in 1995. The site is in Somerset, on the same coastal strip as the retired Hinkley Point A and Hinkley Point B stations. The technology is the EPR, a third-generation pressurised water reactor of 1.6 gigawatts gross per unit; the pair gives 3.2 gigawatts of gross capacity, around 3.0 gigawatts of net. The station is contracted under a 35-year Contract for Difference at a strike price of 92.50 pounds per megawatt-hour in 2012 prices, indexed annually; the equivalent strike in 2024 prices sits around 126 pounds per megawatt-hour. Final Investment Decision was reached in September 2016; first concrete on Unit 1 followed in March 2017.

The cost line has moved upward through the construction period. The 2013 strike-price agreement carried a 14 billion pound headline in 2012 prices. The 2016 Final Investment Decision update settled at 18 billion pounds in 2015 prices. The 2019 review brought the estimate to 21 to 22 billion pounds in 2015 prices on the civils-stage schedule. The 2022 review settled at 25 to 26 billion pounds in 2015 prices after the pandemic-period schedule revisions. The 2024 operator update set the cost in nominal terms at 46 to 47 billion pounds, with first power then expected on Unit 1 in 2029; EDF's February 2026 reconfirmation moved Unit 1 to 2030, with Unit 2 around 2032. The cost increase has not been carried by the consumer through the strike price (which is fixed in real terms under the Contract for Difference), but by the equity holders in the project (EDF, with China General Nuclear Power Corporation having exited the equity position).

The reading from the cost trajectory is two-part. First, the headline number has moved across the construction period in line with the schedule slip; a year-on-year construction cycle on a large pressurised water reactor carries financing cost, schedule contingency and labour rates that compound when civils stages extend. Second, the cost has landed on the equity holders rather than on the consumer, because the Contract for Difference fixed the strike price in real terms. The Sizewell C consortium chose the Regulated Asset Base model in part to put this cost-overrun risk into a regulated framework, where the Crown takes a position alongside the private equity and Ofgem sets the allowed revenue. The next section works through that contractual choice.

Sizewell C: the Regulated Asset Base FID of July 2025

Sizewell C reached Final Investment Decision on 22 July 2025 under the Regulated Asset Base model authorised by the Nuclear Energy (Financing) Act 2022. The site is on the Suffolk coast, adjacent to the operating Sizewell B station. The technology is the EPR, an exact sibling of the Hinkley Point C reactors, giving a 3.2 gigawatts gross EPR pair. The headline capital estimate at Final Investment Decision is 38 billion pounds in 2024 prices; the equity stack closed at 14.2 billion pounds across the Crown (through DESNZ at around 44 percent), EDF (at around 12.5 percent), La Caisse de depot et placement du Quebec (at around 20 percent) and Centrica (at around 15 percent), with the residual taken by smaller institutional investors; the debt stack closed at 36.6 billion pounds at financial close.

The Regulated Asset Base model is the contractual mechanism that distinguishes Sizewell C from Hinkley Point C. Under a Contract for Difference, the developer carries the cost-overrun risk and earns a fixed strike price on each delivered megawatt-hour from commissioning. Under a Regulated Asset Base, the developer recovers an allowed revenue stream during construction (the consumer pays a small per-bill construction levy from financial close) and an allowed revenue stream after commissioning, with the allowed revenue set by Ofgem under the framework of the Nuclear Energy (Financing) Act 2022. The model carries three primary effects: it lowers the cost of capital because the construction-stage cash flow reduces the discount rate the project finance can sustain; it shares the cost-overrun risk between developer, debt holders and consumer; and it transfers procurement discipline to Ofgem's allowed-revenue determination.

The 22 July 2025 financial close also confirmed the Special Administrator regime under the Nuclear Energy (Financing) Act 2022. The regime sits as the consumer-protection backstop: if the licence holder is unable to continue financing the construction, the Secretary of State may appoint a Special Administrator to run the project on a contractual basis until either the licence is transferred or the project is wound up. The Special Administrator regime is the equivalent of the regime in the Energy Act 2011 for energy supply licence holders, adapted for the long-dated construction profile of a new pressurised water reactor pair. The Act sits within the Section 6 licence regime under the Electricity Act 1989, which holds the Generation Licence that Sizewell C Limited has secured.⁴

The reading on the procurement step is that the Sizewell C consortium took the lessons from the Hinkley Point C cost line and rebuilt the financial structure to fit. The Regulated Asset Base model brings the financing cost down, brings the Crown into the equity, and brings Ofgem in to set the allowed revenue. The headline 38 billion pound estimate sits below the 46 to 47 billion pound nominal Hinkley Point C estimate in like-for-like terms after price-base alignment, mostly because the Sizewell C site benefits from the design-replication learning and the civils-stage acceleration that the Hinkley Point C build absorbed. The in-service window remains mid-2030s.

The Wylfa Small Modular Reactor site contract of April 2026

The Wylfa Small Modular Reactor site contract is the single largest commitment in the new-build picture inside the last twelve months, and it sits at the front of the nuclear conversation alongside the Sizewell C Final Investment Decision. The site is on the north coast of Anglesey, the location of the former Magnox station Wylfa A (operated 1971 to 2015) and the abandoned Hitachi Wylfa Newydd project (cancelled January 2019 when Hitachi withdrew). The Anglesey site retains the cooling-water and grid-connection assets that the Magnox station and the Newydd planning consent established.

The DESNZ written ministerial statement of 13 November 2025 set out the site selection. The April 2026 contract announcement confirmed the structure: three Rolls-Royce Small Modular Reactor units, each rated at 470 megawatts gross (1.41 gigawatts gross for the trio), under a procurement led by Great British Nuclear with a 2.5 billion pound budget envelope to Final Investment Decision. The Small Modular Reactor design is the Rolls-Royce SMR, a 470-megawatt pressurised water reactor that completed Step 2 of the Generic Design Assessment in 2024 and is in Step 3. Step 3 closure is the gateway to a site licence application; the licensee structure is expected to be settled before Final Investment Decision in 2029. The in-service window for the first unit sits in the mid-2030s.⁶

The procurement mechanism differs from both Hinkley Point C and Sizewell C. The Small Modular Reactor route runs through a Great British Nuclear-led site contract rather than a stand-alone Contract for Difference or a stand-alone Regulated Asset Base designation. The procurement choice reflects the smaller unit size (470 megawatts versus 1.6 gigawatts), the design replication that the Small Modular Reactor concept is built around (a factory-built reactor module shipped to site rather than a stick-built civils stage), and the lower per-unit cost-overrun envelope. Great British Nuclear sits as the public procurement vehicle authorised by DESNZ in March 2023 with the explicit remit to bring the Small Modular Reactor pipeline through procurement and to Final Investment Decision.¹

The reading from the Wylfa contract is that the Small Modular Reactor route is the procurement mechanism that the Great Britain new-build pipeline needs alongside the large pressurised water reactor route. The large reactor route at Hinkley Point C and Sizewell C is sized for the bulk firm capacity that the carbon-zero electricity system needs at the 3 gigawatt scale. The Small Modular Reactor route at Wylfa is sized for the modular factory-build cycle, the smaller per-unit overrun envelope, and the lighter civils footprint. The combined trio at Wylfa gives 1.4 gigawatts of firm capacity at the mid-2030s window, on a procurement schedule that DESNZ, Great British Nuclear, Rolls-Royce SMR Limited and the Office for Nuclear Regulation will hold through the Final Investment Decision step in 2029.

The statutory frame: the 1965 Act, ONR site licences and the Generic Design Assessment

Every commercial nuclear site in Great Britain holds a Nuclear Site Licence issued by the Office for Nuclear Regulation under the Nuclear Installations Act 1965. The Act, originally enacted to give effect to the Paris Convention on third-party liability in the field of nuclear energy, set out the licensing regime that has governed the Great Britain nuclear estate for more than sixty years. The licence is held by the operator of the site (Sizewell B by EDF Energy Nuclear Generation Limited, Hinkley Point C by NNB Generation Company (HPC) Limited, Sizewell C by Sizewell C Limited) and carries thirty-six standard conditions covering safety case, design, construction, operation, decommissioning, security, emergency arrangements, and inspection. Each licence runs without time limit but is conditional on the operator's continuing compliance with the conditions and on the safety case the Office for Nuclear Regulation accepts on each Periodic Safety Review.

Alongside the site licence sits the Generic Design Assessment, the four-step technical review by which the Office for Nuclear Regulation and the Environment Agency together assess a reactor design before any site-specific construction proposal. The Generic Design Assessment runs across Steps 1 to 4 over a typical period of three to four years and produces a Design Acceptance Confirmation from the Office for Nuclear Regulation and a Statement of Design Acceptability from the Environment Agency. The EPR design that sits at Hinkley Point C and Sizewell C completed the Generic Design Assessment in December 2012. The Rolls-Royce Small Modular Reactor design completed Step 2 in 2024 and is in Step 3 in 2026. The GE Hitachi BWRX-300 design completed the Generic Design Assessment in December 2025. The Holtec SMR-300 design completed the Generic Design Assessment in March 2026.

The Office for Nuclear Regulation was established as an independent statutory regulator under the Energy Act 2013, taking over from the Health and Safety Executive's Nuclear Directorate that had carried the nuclear regulatory function across the previous decades. The Energy Act 2013 also rebuilt the funding model for new nuclear, introducing the Contract for Difference that Hinkley Point C uses as its strike-price mechanism, and rebuilt the planning regime under the Planning Act 2008 (with the EN-6 Nuclear National Policy Statement first published in 2011 and revised through to the 2025 EN-7 successor). The Nuclear Energy (Financing) Act 2022 added the Regulated Asset Base model that Sizewell C uses. The statutory stack therefore has the 1965 Act at the base for the site licence regime, the Energy Act 2008 for the modern nuclear regime, the Energy Act 2013 for the Office for Nuclear Regulation and the Contract for Difference, the Nuclear Energy (Financing) Act 2022 for the Regulated Asset Base, and the Energy Act 2023 for the wider planning and procurement reform that underpins Great British Nuclear.^{4 1}

The Climate Change Act 2008 sits alongside the nuclear statutory stack and gives the carbon binding for the firm low-carbon dispatchable role that nuclear plays. The Act, amended in June 2019 to set the net-zero greenhouse gas emissions target by 2050, established the Committee on Climate Change as the independent statutory advisor and the carbon budget regime that holds the Crown to a five-year accounting cycle. The Sixth Carbon Budget (covering 2033 to 2037) was adopted in 2021. The Climate Change Act is the parent instrument behind the Clean Power 2030 commitment, behind the Connections Reform Gate 2 outcomes, and behind the firm-capacity arithmetic that nuclear delivers into 2030.¹

Decommissioning: the NDA estate, Magnox closure and the Sellafield wind-down

The Great Britain decommissioning legacy is owned by the Nuclear Decommissioning Authority, a non-departmental public body created by the Energy Act 2004. The Authority holds seventeen sites: the eleven Magnox stations (all closed; the last to close was Wylfa A in December 2015), the two early commercial sites at Berkeley and Bradwell, the research sites at Harwell and Winfrith, the Dounreay fast-reactor site in Caithness, and Sellafield in West Cumbria. The estate sits inside a 149 billion pound lifetime decommissioning cost estimate in the Authority's 2025 annual report, on a discounted basis at a multi-decade discount cadence. The estate management contractor for each site is held under a Parent Body Organisation arrangement, with the Authority retaining ownership of the assets and the contractual relationship with the operator. The Office for Nuclear Regulation regulates the safety of each decommissioning site under the same site licence framework that governs the operating fleet.

The Magnox stations represent the first generation of commercial pressurised gas-cooled reactors in Great Britain. The fleet ran from 1956 (Calder Hall, the world's first commercial nuclear station) through to the December 2015 closure of Wylfa A. Each station holds a Nuclear Site Licence and progresses through defuelling, then care and maintenance, then Final Site Clearance under the Authority's lifetime plan. The defuelling step removes the irradiated Magnox fuel for reprocessing or interim storage; the care and maintenance step protects the reactor structure and the contaminated water systems until the final demolition window opens, typically eighty to one hundred years after closure to allow short-lived activation products to decay. The cost of each station's lifetime plan sits inside the Authority's total estate estimate.

Sellafield in West Cumbria carries the largest single element of the decommissioning workload, on the order of 70 percent of the Authority's lifetime cost estimate. The site holds the historical nuclear fuel reprocessing facilities (the Magnox Reprocessing Plant, which closed July 2022 after sixty-six years of operation, and the Thermal Oxide Reprocessing Plant, which closed November 2018), the High Level Waste Plants that vitrify the residual high-level waste into glass blocks for interim storage, the Magnox spent fuel storage ponds, and the historical First Generation Magnox Storage Pond and First Generation Magnox Storage Silo (both on the High Hazard Risk Reduction programme). The legacy plant inventory sits across hundreds of buildings and tens of thousands of separate items.

The Authority's annual report sets the lifetime cost estimate against a long horizon. The 149 billion pound figure spans the next century and a half on a discounted basis. The reprocessing wind-down at Sellafield is now complete; the remaining work is the dismantling of the reprocessing plants, the retrieval of historical waste from the legacy pond and silo, the vitrification of remaining liquid high-level waste, and the long-term geological disposal facility that Nuclear Waste Services (the Authority subsidiary established in February 2022) is developing under the Managing Radioactive Substances and Nuclear Decommissioning National Policy Statement.¹

The firm dispatchable role in the carbon arithmetic to 2030

Nuclear sits inside the Clean Power 2030 commitment as the firm low-carbon dispatchable layer alongside long-duration storage, hydrogen-ready dispatchable plant and interconnector imports. The action plan published by DESNZ and NESO on 5 December 2024 sets a target of 95 percent low-carbon electricity by the end of 2030, with up to 5 percent of annual energy from unabated gas retained as a resilience buffer for low-renewables weeks. The annual energy split that the action plan profiles has variable renewables (offshore wind, onshore wind, solar) at around 60 to 65 percent of annual generation, firm low-carbon dispatchable at around 30 to 35 percent, and the residual unabated gas at the 5 percent cap. Nuclear holds the bulk of the firm low-carbon dispatchable share through 2030.³

The capacity arithmetic to the early 2030s reads as a step-down and then a recovery. Through early 2028 the operating fleet is Sizewell B at 1.2 gigawatts plus the four Advanced Gas-cooled Reactors at 4.79 gigawatts: a total of about 6 gigawatts of firm dispatchable nuclear. In March 2028 Heysham 1 (1.18 gigawatts) and Hartlepool (1.18 gigawatts) close, taking the firm total down to about 3.6 gigawatts. In March 2030 Heysham 2 (1.23 gigawatts) and Torness (1.20 gigawatts) close, taking it down to 1.2 gigawatts, Sizewell B alone. The Hinkley Point C commissioning ramp, on EDF's targets, brings Unit 1 (1.6 gigawatts) in 2030 and Unit 2 (1.6 gigawatts) around 2031 to 2032. The firm nuclear total therefore bottoms at Sizewell B alone around early 2030 and recovers to about 2.8 gigawatts once Hinkley Point C Unit 1 is in service, lifting to about 4.4 gigawatts when Unit 2 follows; the depth and length of the Sizewell-B-only trough depend on the Hinkley Point C schedule holding to 2030.

The annual energy contribution sits below the capacity total because the Hinkley Point C ramp takes nine to twelve months from first synchronisation to full commercial output, and because the maintenance and refuelling outage cycle on each station reduces the available factor by a few percentage points. Reading across the action plan window, nuclear delivers approximately 35 to 40 terawatt-hours of annual generation while the full fleet runs to 2028, sliding to about 8 to 10 terawatt-hours around 2030 (Sizewell B alone), then recovering to about 22 to 28 terawatt-hours during 2031 to 2032 with the Hinkley Point C ramp; this is in the range of 8 to 10 percent of annual generation against a 285 to 300 terawatt-hour total demand window. The firm dispatchable role sits at about 2.8 gigawatts once Hinkley Point C Unit 1 is in commercial service, with Unit 2 to follow. The Wylfa Small Modular Reactor pipeline and Sizewell C do not contribute in the 2030 window; both deliver in the mid-2030s.⁵

The dispatchable nature of nuclear in the system is the operational complement to its low-carbon contribution. Sizewell B and the Advanced Gas-cooled Reactor fleet run at base-load through the day with a small load-following capability between minimum stable generation and full output; Hinkley Point C will run on the same operational pattern. The Capacity Market T-4 auction for 2029 to 2030 procures the dispatchable layer that sits alongside nuclear (40.1 gigawatts of de-rated capacity cleared at 27.10 pounds per kilowatt year on 25 February 2026); nuclear sits outside the Capacity Market because its long-dated procurement runs through the Contract for Difference at Hinkley Point C, the Regulated Asset Base at Sizewell C and the Great British Nuclear site contract at Wylfa. The firm low-carbon dispatchable share that nuclear holds is therefore a discrete component of the action plan trajectory, sized through the reactor commissioning schedule rather than through the annual auction cycle.¹

How the firm dispatchable contribution reads against the December 2024 action plan

The 95 percent low-carbon commitment reads usefully as a layered annual energy budget. Around 60 to 65 percent of the annual energy comes from variable renewables. The variable share is supported by long-duration storage discharge into the low-renewables windows, by demand-side response, by interconnector imports from linked systems with low marginal cost, and by the firm low-carbon dispatchable layer. The firm low-carbon dispatchable layer sits at around 30 to 35 percent of annual energy. Of that 30 to 35 percent, nuclear holds the largest single share through 2030, at around 8 to 10 percent of annual generation; the residual is taken by long-duration storage discharge, by interconnector imports and by hydrogen-ready dispatchable plant. The remaining 5 percent of annual energy is the unabated gas residual under the action plan envelope.

Reading the action plan against the operating fleet, two structural points sit at the front. First, the firm dispatchable contribution from nuclear narrows around 2030 to a single station (Sizewell B at 1.2 gigawatts) before the Hinkley Point C ramp lifts it. The window around 2030 therefore depends on the dispatchable layer carrying the firm role through long-duration storage, hydrogen-ready dispatchable plant and interconnector imports while the Hinkley Point C commissioning step closes. Second, the recovery to about 2.8 gigawatts of firm nuclear once Hinkley Point C Unit 1 is in service sits below the about 6 gigawatts the fleet carried in mid-2026, and the remaining shortfall is taken by the other components of the firm low-carbon dispatchable layer. The action plan profiles both layers together; reading the procurement results against the layer-by-layer envelope is the way to check whether the trajectory holds.

The Wylfa Small Modular Reactor trio and Sizewell C lift the firm nuclear capacity in the mid-2030s window. The combined contribution of the three new reactors at Wylfa (1.4 gigawatts gross) plus the Sizewell C EPR pair (3.2 gigawatts gross) brings the firm nuclear total to around 9 gigawatts in the mid-2030s, before any further life-extension decision on Sizewell B and before any further Small Modular Reactor deployment under the Great British Nuclear pipeline. Reading the firm nuclear contribution into 2035 and beyond sits in a different policy window from the Clean Power 2030 commitment; the procurement results for the 2030 window are the Hinkley Point C completion and the Sizewell B continuation, and the procurement results for the 2035 window are the Sizewell C completion and the Wylfa Small Modular Reactor commissioning.