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EPR Being Built at Hinkley Point C

Date released
12 November 2024
Request number
202410054
Release of information under
Freedom of Information Act 2000 (FOIA)

Information requested

I had some questions regarding the EPR reactor being built at Hinkley Point C:

  1. What percentage of the detailed engineering design or construction-ready blueprints were complete when Hinkley Point C received its construction license?

    Incomplete construction-ready detailed engineering designs are proven contributors to cost overruns and delays in nuclear construction projects such as Flamanville, Olkiluoto, VC Summer and Vogtle.

    When the final design acceptance confirmation was issued in December 2011, it was reported that there were 724 unresolved assessment findings. Here's the link to the source. Hinkley C: the Generic Design Assessment has failed (theecologist.org)

  2. I have the ONR reports for the breakdown of the 7000 design changes and the 31 GDA issues but not the 724 unresolved assessment findings. What exactly were the breakdown?
  3. What were 16 design changes which were related to Fukushima? (one of them was flooding) I have a copy of the report 'ONS regulatory influence on the EPR design change'.
  4. How many of the 2000 design changes (which the report ) were related to the third non-computerised full analogue control room?
  5. What was the justification for following design changes?
  • number I&C cabinets doubling from 18 to 36
  • an extra floor on the safety trains and diesel generator buildings
  • spent fuel building needed a third diverse PTR train
  • steam generator tube rupture detection system had to modified
  • reactor coolant pump rundown sensors had to be modified

Information released

We confirm that under s.11 of the FOIA, we hold some of the information you have requested and where the information to a question is not held or cannot be treated as an FOI request, we have endeavoured to answer them as part of our normal customer service.

Question 1

It is common practice in engineering projects of this scale to start some construction and manufacturing activities prior to completion of all design work. We are confident that when the Generic Design Assessment (GDA) was conducted, the generic UK European Pressurized Reactor (EPR) design was appropriately mature to be assessed in this way. The specific percentage of the detailed engineering design or construction-ready blueprints is not information that we hold.

Question 2

The outstanding assessment findings are continuing to be resolved in line with the closure plan. As of October 2024, 255 assessment findings are still open.

Question 3

The matters of design changes at Fukushima are addressed in the report “Summary of the GDA Issue close‐out assessment of the Electricité de France SA and AREVA NP SAS UK EPR™ nuclear reactor” which was published on 13 December 2012.

On pages 61 and 63 of the report, in relation to ‘Closure of GI‐UKEPR‐CC‐03’, it states;

“This GDA Issue requested EDF and AREVA to demonstrate how they will take account of lessons learnt from the events at Fukushima, including those lessons arising out of EDF and AREVA’s own internal reviews and the lessons and recommendations identified in HM Chief Inspector’s (CI) final report. The approach taken by EDF and AREVA was to review the robustness of the UK EPR design against severe external events and, where appropriate, to identify and develop potential design enhancements recognising developments in other EPR projects and wider international initiatives.” 

From their reviews, EDF and AREVA identified 16 resilience enhancements that they grouped into five design change proposals for GDA and these provide the following:

  • Improved flood protection for emergency electrical supplies (both alternating current (AC) and direct current (DC));
  • Extension of the capability and autonomy of emergency electrical supplies (both AC and DC);
  • Identified connection points for proposed mobile diesel generators;
  • Addition of spent fuel pool (SFP) instrumentation into the severe accident management (control and instrumentation) systems; and,
  • Provision of connections to enable delivery of water via mobile pumps for SFP make‐up and containment pressure control.

On the basis of our assessment of the information provided by EDF and AREVA we are satisfied that the lessons learnt from Fukushima and the requirements of GDA Issue GI‐UKEPR‐CC‐03 have been addressed.

Question 4

The specific number of individual design changes associated to modifications is not information that we hold. This information would be held by NNB GenCo and EDF, and we would suggest contacting them directly for further assistance.

Question 5

We have assessed and published the findings of our regulatory influence on the EPR design in the UK on our website which provides the reasoning behind the design changes. As this information is already reasonably accessible to you via our website, s.21 of the FOIA prescribes that it is exempt from disclosure.

Exemptions applied

s.21

PIT (Public Interest Test) if applicable

N/A