nuclear-news

More issues reported during manufacture of Sizewell C’s reactor vessels than Hinkley Point C’s

01 Jul, 2026 By Tom Pashby, https://www.newcivilengineer.com/latest/more-issues-reported-during-manufacture-of-sizewell-cs-reactor-vessels-than-hinkley-point-cs-01-07-2026/

“Quality issues” relating to the manufacture of the reactor pressure vessels (RPVs) for Sizewell C have been identified by the Office for Nuclear Regulation (ONR) during an inspection by the regulator.

The number of “non-conformance reports” has increased at Framatome St Marcel (FSM) – the French manufacturer of the RPVs – compared to when it was manufacturing the RPVs for Hinkley Point C.

Sizewell C and the Department for Energy Security and Net Zero (DESNZ) have regularly highlighted how Sizewell C will be delivered more efficiently than Hinkley Point C because of how much design work can be copied over.

The Sizewell C – Inspection ID: 54200 report from the ONR, which was carried out in April 2026 and published on 22 June, reported that “manufacturing quality issues” had been identified at FSM.

The ONR stressed the importance of the RPV in its report. “The reactor pressure vessel (RPV) is manufactured by Framatome (manufacturer of nuclear equipment based in France),” it said.

“The RPV is a nuclear safety class 1 component which forms part of the primary circuit. It has been categorised as a high integrity component (HIC) within the SZC safety case.

“Therefore, the consequences of failure during operation cannot be tolerated and a highest reliability claim is made on the structural integrity of the RPV.”

The aim of the ONR’s inspection was for it to “make an informed judgement on the adequacy of SZC’s specification, control and oversight of RPV manufacture at FSM in compliance with LC12 and LC19.”

LC12 means License Condition 12, and required that “the licensee (meaning Sizewell C) shall make and implement adequate arrangements to ensure that only suitably qualified and experienced persons perform any duties which may affect the safety of operations on the site or any other duties assigned by or under these conditions or any arrangements required under these conditions.”

Meanwhile, LC19 requires that “where the licensee proposes to construct or install any new plant which may affect safety the licensee shall make and implement adequate arrangements to control the construction or installation.”

July 3, 2026 - Posted by Christina Macpherson | safety, UK