Office for Nuclear Regulation

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Sea level rises

Date released
14 February 2019
Request number
Release of information under
Freedom of Information Act 2000

Information requested and released

For ease we have listed your questions and ONR’s answers below:

Question 1

You state that the Licensee NNB GenCo conducts detailed studies of the potential for flooding hazards at their site, and that these studies include an allowance for “reasonably foreseeable sea level rise.” We would be very interested to know how you verify these studies and how the “reasonably foreseeable sea level rise” is defined. Would we be able to see a copy of the relevant studies?

ONR’s response to question 1

ONR undertakes assessment of safety cases produced and owned by the nuclear licensees, in this case NNB GenCo for Hinkley Point C (HPC). Assessment of the safety case includes sampling of the supporting evidence and studies. A public version of the HPC Pre-Construction Safety Case is published by NNB GenCo on the EDF download centre. The sub-chapters relevant to the flooding hazard definition and the plant response are 2.1 and 13.1 respectively.

The expectation is that the reasonably foreseeable effects of climate change over the lifetime of the facility should be taken into account. ONR does not provide a definition of reasonably foreseeable sea level rise, as a non-prescriptive regulator. The reasonably foreseeable effects of climate change are site and technology dependent and are the responsibility of the licensee to justify.

The expert panel papers on meteorological hazards and coastal flooding provide guidance on the current understanding of climate change and the areas of interest for assessing the treatment of climate change. Details are included in the technical assessment guidance on External Hazards - NS-TAST-GD-013, Revision 7.

Question 2

Just in the last few weeks several new studies have been published which appear to change what might be reasonably foreseeable. Two papers highlight the impacts of rising global temperatures, which may cause the ice sheets to soon enter a phase of irreversible retreat and raise global sea levels for hundreds to thousands of years. What is worrying is that the rate ice is melting seems to be increasing.

Another study suggests that East Antarctica’s glaciers are melting faster than previously thought. This prompted Chris Fogwill, a professor at Keele University to suggest that “…our sea-level projections could be an order of magnitude higher than we’re anticipating.”

This suggests that the ‘reasonably foreseeable sea level rise’ seems to be rather a moving target, as is the “maximum credible scenario” discussed in the Principles for Flood and Coastal Erosion Risk Management. Given that EN-1 and UKCP09 are now both around a decade old has the ‘credible maximum scenario for sea level rise and storm surge been revised?

ONR’s response to question 2:

ONR’s expectation is for NNB GenCo to demonstrate application of Relevant Good Practice when developing its safety case; this applies to the external hazards aspects of the safety case. ONR does not identify Relevant Good Practice but provides guidance on its selection and application through its technical assessment guidance on External Hazards - NS-TAST-GD-013, Revision 72. This guidance is produced for the ONR assessors and is published to provide transparency of regulation to the industry and public.

It is not reasonable to expect licensees to reconsider safety cases against every new academic publication or press article, ONR would however expect that where assumptions in the safety case were challenged that the implications for the safety case would be considered by the licensee. For example the implications of the revised UK Climate Projections UKCP18 are included on the met office website and will be considered by nuclear site licensees in due course.

Question 3

You say that the Licensee will monitor the flooding hazard in Periodic Safety Reviews (PSR). But, of course the first Hinkley Point C PSR won’t be due until the station has been operating for ten years. ONR’s PSR3 Assessment Report for Hinkley Point B and Hunterston B makes only one brief mention of sea defences, so it is difficult for interested members of the public to assess the work of the Licensee and the Regulator on sea-level rise. As things stand it looks as though we may have to wait until almost 2040 to get a better idea.

Can you tell us who the members of your independent expert panel on meteorological hazards are and how often they meet? Can we see the minutes of any meetings where Hinkley Point C was discussed?

ONR’s Request for Refinement on question 3

With regard to the minutes of the meetings you wish to see, please can you confirm that you wish to see only the sections of the minutes relating specifically to Hinkley Point C.

Refinement Response for question 3

With regard to the minutes of the meetings of your independent expert panel on meteorological hazards, we would like to confirm that we would like to see the minutes relating to Hinkley Point C and the minutes relating to all the other new nuclear UK coastal sites.

ONR’s response to question 3

ONR will expect the Licensee to maintain the flooding safety case through the various stages up until operation, and may choose to sample this process.  Furthermore, should information become available which potentially challenges the safety case, ONR may choose to undertake a review of the implications and use appropriate regulatory tools to ensure timely licensee compliance.

The ONR expert panel on Natural Hazards (Sub-Panel on Meteorological and Coastal Flood Hazards) meets approximately annually. Its advice on meteorological hazards and coastal flood hazards has been collated into two Expert Panel Papers.
These papers provide the expert advice underpinning the guidance to ONR Inspectors contained in the technical assessment guidance on External Hazards - NS-TAST-GD-013, Revision 7.

Members of the ONR expert panel on Natural Hazards (Sub-Panel on Meteorological and Coastal Flood Hazards) are:

The Expert Panels currently provide high quality technical advice to ONR’s external hazards team on seismicity, climate change and coastal flooding. They were set up in 2010, became fully functional in 2011, and were tasked to assist the external hazards team primarily on new reactor licensing and construction projects, where licensees would be submitting technically sophisticated external hazards safety cases.

The membership of the panels has changed since their inception but their purpose has remained consistent. It was considered important that the ONR External Hazards team had access to independent expertise, so that the regulatory judgments made by the team could be based on high quality, credible advice.

The Expert Panels are groups of academics and specialist consultants covering a range of skill areas relevant to seismic and coastal flooding hazards and climate change. These skills are needed to meet the assessment needs of ONR in respect of new nuclear build and revisions to TAG guides. Expert Panel members are deployed to provide support to the external hazards specialist inspectors, the intent is that they provide a resource that ONR can call on whenever it needs expert guidance on the technologies it covers.

Regulatory decisions and technical guidance remain the responsibility of ONR inspectors, the minutes of the expert panel meetings should therefore be viewed as a record of discussions by the panel members under the chair of ONR. They should not be interpreted as guidance or regulatory advice. It is important that a wide variety of views are heard in the expert panel and that this information can be accurately condensed into guidance for ONR inspectors. The minutes contain a record of these discussions.

The minutes of the expert panel meetings should not be used out of context, the consolidated technical advice from the expert panels can be found in the expert panel papers which support the technical assessment guidance on External Hazards - NS-TAST-GD-013, Revision 7.

Please find attached in Annexes A-D the sections of the minutes of the ONR expert panel on Natural Hazards (Sub-Panel on Meteorological and Coastal Flood Hazards) relevant to HPC and all other new nuclear UK coastal sites in relation to flooding and climate change. Elements of these sections have been redacted due to the material contained being exempt from disclosure.

Redactions - Exemptions applied

Section 40 – Personal Information

Information has been redacted because it is personal data, so it has been withheld applying the exemption Section 40 of the FOIA. This is an absolute exemption so does not require a Public Interest Test.

Section 38 – Health and Safety and Section 43 – Commercial Interests

Two sentences in Annex A have been redacted applying the exemptions Section 38 and Section 43 of the FOIA. Both are qualified exemptions and therefore the public interest test applies.  We consider that applying the exemptions in this case, outweighs the public interest for disclosure for the following reasons:

Public Interest Test

Factors for release:

The public have a vested interest in issues related to the nuclear industry, and in matters relating to public safety impacts.

Factors against release:

Disclosing has the potential to cause alarm and distress; the information is no longer accurate; this is not a case where there is any regulatory challenge.


After careful consideration of the factors set out above, ONR has concluded that the information should be withheld under Section 38 and Section 43 of FOIA 2000.  Release of the redacted information is not in the public interest as:

The attached minutes are:

Question 4

In your ‘Principles’ document you state that “it is prudent to ensure that there are no features of the design which are completely undermined by more radical changes to the climate.” Can you foresee any circumstances which might require spent fuel to be removed from the site quickly and if so do you think this would be feasible, bearing in mind that we might be talking about over 100 years in the future?

We feel that as scientific evidence is changing rapidly regarding climate change, the wisdom of choosing nuclear power must be questioned, especially as the nuclear waste is likely to remain on site in wet storage ponds for at least 160 years.

ONR’s response to question 4:
As described above, the licensee is expected to take account of reasonably foreseeable effects of climate change over the lifetime of the facility. The ONR assessment of the HPC Interim Spent Fuel Storage Facility will therefore consider the treatment of climate change in the safety case over the lifetime of the facility. As an interim facility it is inherent in the design of the Interim Spent Fuel Store that the fuel can be removed from site. The safety case will have to consider the consequences of site flooding.

ONR is content that a suitable managed adaptive approach can be adopted, in the event that sea level rise is more than predicted over the lifetime of the reactors, as set out in the Principles for Flood and Coastal Erosion Risk Management.

Exemptions applied

PIT (Public Interest Test) if applicable