From a riverside industrial hub in eastern France, a piece of steel engineering the size of a small house is beginning a carefully managed trip to the UK. The 500‑tonne reactor pressure vessel for Hinkley Point C’s second unit has been completed by Framatome at Saint-Marcel, near Chalon-sur-Saône, and is now bound for the massive nuclear construction site on the Somerset coast.
The component matters because it is designed to sit at the centre of an EPR (European Pressurised Reactor), helping to determine how much reliable, low‑carbon power Britain can count on in the 2030s—at a time when the grid is rapidly adding wind and solar but still needs firm generation.
Why this shipment is a milestone for Hinkley Point C
Framatome finished the reactor pressure vessel for Unit 2 on 28 November 2025. The vessel weighs around 500 tonnes and measures roughly 13 metres long. Once installed, it will house the reactor core—one of the most safety‑critical areas of the entire plant.
Hinkley Point C is being built with two EPR units. Each reactor is rated at 1,630 MW, which would make each unit more powerful than any current operational reactor in the UK. Together, the project is expected to supply around 7% of the country’s electricity demand.
A complex journey from Burgundy to the Somerset coast
Moving a component of this size is not a typical logistics job. The vessel’s route involves staged transport designed for extreme loads: it travels by barge, then by sea across the Channel, and finally by heavy‑haul convoy to the Hinkley Point C site.
The timing also aligns with other major steps at Unit 2. The reactor dome for the second unit had already been lifted into place shortly before the pressure vessel left France, reflecting the sequence required to assemble the reactor building.
What the reactor pressure vessel actually does
Although it looks like a giant steel cylinder, the reactor pressure vessel functions as a sealed barrier around the reactor core. It contains fuel assemblies and control components, while holding pressurised cooling water that circulates through the primary circuit.
Operating conditions are extreme: temperatures can exceed 300°C and pressure can exceed 150 bar. The materials must also withstand long-term neutron exposure. Because of this, fabrication is slow and tightly controlled, with extensive inspections of welds and interfaces before shipment.
At Saint-Marcel, large steel pieces are forged, heat treated, machined and checked through a multi‑stage process that can take years. The objective is long service life—up to decades of operation—with safety margins aligned with nuclear regulation.
How Unit 2 fits into the wider Hinkley construction timeline
This is the second reactor pressure vessel destined for Hinkley Point C. The first vessel reached Somerset in 2023 and was installed in its reactor building in December 2024. Unit 2 is expected to follow a similar installation sequence once the remaining associated components arrive on site.
Current project timing and milestones disclosed in the source include:
- Start of main construction works at Hinkley Point C: 2018
- Reactor dome installed on Unit 1: late 2023
- Reactor vessel 1 delivered: early 2023; installed in 2024
- Reactor vessel 2 completed in France: November 2025
- Planned commercial operation of Unit 1: 2030
- Planned commercial operation of Unit 2: 2031
Costs, controversy and why the UK is still pushing ahead
Hinkley Point C is the UK’s first new nuclear power station in more than 30 years, and it remains one of the country’s most debated infrastructure projects. According to the source, official cost estimates now sit at £31–34 billion in 2015 money, higher than earlier projections.
EDF, which leads the project, argues the cost reflects first‑of‑a‑kind challenges in the UK and the scale of the build. Supporters also position Hinkley as a learning project that could reduce risk, shorten schedules and lower costs for future EPR developments such as Sizewell C.
More giant components: steam generators are also on the move
The pressure vessel is only one of several oversized pieces required to build an EPR. Framatome also produces the steam generators—massive heat exchangers that transfer heat from the primary circuit to a secondary circuit that produces steam for the turbine.
Each steam generator is about 25 metres tall and weighs around 520 tonnes. The first steam generator for Hinkley Point C arrived in Somerset in May 2024 and was installed in Unit 1 two months later. For Unit 2, two generators have already left the factory, with remaining deliveries scheduled by 2026 to match the installation timetable.
France’s role inside a British energy strategy
The arrival of a French‑manufactured reactor vessel also highlights how international the UK’s nuclear supply chain is—something that continues to draw political attention, particularly in the post‑Brexit context. At the same time, UK‑France nuclear cooperation is long‑standing, and Hinkley Point C effectively deepens that relationship through a shared EPR technology base and a cross‑border industrial footprint.
The source also places Hinkley within the broader EPR landscape, where builds in France and Finland faced delays and overspends, while China delivered earlier units faster but experienced technical issues. Lessons from those projects have influenced tighter quality controls and updated standards as the UK build continues.
Why this 500‑tonne cylinder has climate and grid implications
At a systems level, the question is not only about engineering—it is about how the UK balances a grid increasingly powered by variable renewables. Without a new large plant like Hinkley Point C, Britain would likely rely more on gas-fired generation for firm capacity, or invest more heavily in long‑duration storage and grid reinforcement.
Nuclear’s trade‑offs remain: high upfront capital costs, long construction timelines, and challenging debates around waste and decommissioning. But once online, the plant is expected to operate for decades, providing a large block of low‑carbon electricity independent of weather conditions—an attribute policymakers often treat as strategic for the 2030s and beyond.
Keys
- Framatome completed the Unit 2 reactor pressure vessel for Hinkley Point C on 28 November 2025 at Saint-Marcel near Chalon-sur-Saône.
- The component weighs around 500 tonnes and is roughly 13 metres long, and will house the core of an EPR reactor.
- Each Hinkley Point C EPR unit is rated at 1,630 MW; the two-unit project is expected to supply around 7% of UK electricity demand.
- Official estimates cited for the project put total costs at £31–34 billion in 2015 money, with Unit 1 planned for 2030 and Unit 2 for 2031.
- Beyond the pressure vessel, multiple 520‑tonne steam generators are being delivered, with remaining Unit 2 shipments scheduled by 2026.
Source: Aptaerials.co.uk
