Campaigners accuse regulator of failing to assess fracking risk to nuclear station


Hinkley Point C construction site. Photo: EDF

The safety regulator for the nuclear industry has no information about the risk of earth tremors from fracking near the Hinkley Point power station, a campaign group has revealed.

Frack Free Exmoor, Quantocks and Sedgemoor (FFEQS) has also shown that the Office for Nuclear Regulation (ONR) has had no correspondence on the subject with either the oil and gas industry regulator, the power station operator, local exploration companies or Somerset County Council.

FFEQS has described the failure to assess the risk of fracking on the nuclear station, which includes the new Hinkley Point C facility, as “a gaping hole” in the safety case.

In August 2019, fracking by Cuadrilla near Blackpool caused more than 130 earth tremors, including the UK’s largest fracking-induced seismic event, measuring 2.9ML. This tremor led to formal complaints of cracks to walls, windows and doors to about 100 properties, DrillOrDrop understands.

Hinkley Point is a few miles from an area where the exploration company, South Western Energy, has indicated it is interested in drilling for hydrocarbons (DrillOrDrop report).

Opposition to fracking appears to be growing in the region. Sedgemoor District Council voted unanimously on 9 October 2019 to be a Frack Free zone. This follows previous similar votes in Somerset West and Taunton councils.

Hinkley Point Power Station

PEDL licences near Hinkley Point Power Station in Somerset. Map: Oil & Gas Authority

“Cause for concern to local communities”

The issue of seismic risk to the Hinkley nuclear station came to light following a response by the ONR to a freedom of information request

FFEQS founder Kevin Ogilvie-White, who made the request, said:

“The ONR’s response makes it is clear that they have not considered the impact of induced seismicity from potential onshore oil and gas development activity.

“Perhaps the ONR deem the risk to be negligible, but from my perspective a failure to assess this risk represents a gaping hole within their safety case.”

Mr Ogilvie-White said it “seemed absurd” that there had been no correspondence on the subject between the ONR and the company or regulators:

“Should an application be made by South Western Energy, the planning authorities only have 16 weeks to approve or reject the application. The lack of information on this subject should be a cause of concern to councillors, planning inspectors and local communities.”

He said he made the FOI request to find out whether the ONR had revised the probabilistic seismic hazard assessment for the nuclear power station after three exploration licences in the area (PEDLs 334, 321 and 320) were issued to South Western Energy in 2016.

He asked the ONR for any information on a review or planned review of the probabilistic seismic hazard assessment for Hinkley Point from potential oil and gas exploration or development activities.

The ONR replied:

“We confirm that ONR does not hold the information described in your request. ONR are not aware of any information pertaining to review, or plans to review, the Probabilistic Seismic Hazard Analysis (PSHA) for the Hinkley Point C (HPC) site due to potential oil and gas exploration or development activities, including wastewater disposal.”

Mr Ogilvie-White also asked for correspondence on this issue between ONR and any of the following: the Oil & Gas Authority, the holder of the exploration licence, Somerset County Council and representatives of South Western Energy, or two related companies.

The ONR replied:

“We confirm that ONR does not hold the information described in your request. ONR are not aware of any correspondence between the parties highlighted relating to potential petroleum exploration and development activity in the vicinity of Hinkley Point Power Station.”


Mr Ogilvie-White told DrillOrDrop:

“Surely the safety case should include an assessment of probabilistic seismic hazards from frequent low-level events, such as those experienced during fracking by Cuadrilla in Lancashire.”

Last year, the Hinkley operator, EDF, reported a number of cracked fuel bricks in the Hinkley Point B power station. It said they would present a challenge only in the event of a major earthquake.

Earlier this year, a separate FOI request to the ONR revealed:

“the problem that cracked bricks present to the core is that they may allow more freedom of movement of the core structure, particularly during faults such as an earthquake.”

Mr Ogilvie-White said:

“Hinkley is situated in a geologically complex structural setting with the region riddled with north-west and east-west trending faults.

“If the frequency of events, like those induced by fracking in Lancashire, would lead to an unacceptable increase in the number of cracked fuel bricks, which potentially could challenge the safety of control rod insertions, then the obvious outcome of such an assessment should be that onshore oil and gas development activity in the region must be prohibited.”

DrillOrDrop asked the ONR to comment. A spokesperson said:

“As per our Safety Assessment Principles (SAPs) and outlined in Technical Assessment Guide (TAG) 13, the Design Basis Earthquake (DBE) (or seismic design input) for Hinkley Point C (HPC) is based upon a rigorous and robust characterisation of the seismic hazard using probabilistic seismic hazard analysis (PSHA).

“From the outputs of the PSHA, the DBE definition is demonstrated to represent a level of ground motion conservatively estimated to have an annual frequency in exceedance of 10-4/year. This is comparable to a level of ground motion that on average will only be exceeded once every 10,000 years.

“Furthermore, the seismic analysis and broader design process is well established, and incorporates conservatism at various stages, in accordance with relevant good practice for the design of nuclear facilities. This results in a design that will not only meet the demand of the DBE, but also has substantial beyond DBE capability.

“Therefore, induced seismicity arising from postulated future human activity (comprising low levels of ground motion from small magnitude events) is not considered to pose a risk to the HPC facility.”

“Notwithstanding the above, Licence Condition 15 of the standard nuclear site license requires licensee’s to make and implement adequate arrangements for the periodic and systematic review and reassessment of safety cases. Therefore, ONR expects that external hazard safety cases will be periodically assessed by the Licensee to ensure they remain adequate.”

This statement did not satisfy FFEQS. Mr Ogilvie-White said the response did not address the question of frequency of low-level events and, particularly, how they might affect the Hinkley B reactor. He added:

“The statement suggests that ONR has not looked specifically at induced seismicity, as opposed to 1:10,000 year type events, to show conclusively that frequent low-level events do not pose a risk.

“I would have thought that this type of study would be a requirement. If oil and gas development were permitted then the adequacy of the existing traffic light system regulation on seismicity would need to form part of that study.”

13 replies »

  1. I think that FFEQS are correct ( final paragraph ).

    “If oil and gas development were permitted then the adequacy of the traffic light system regulation on seismicity would need to form part of that study”. But it is not likely to be permitted I suspect.

    Tho I think that comment refers to fracking rather than just any oil and gas development, and should refer to the proximity of the activity to the power station, not specifically onshore activity.

    Re the 16 week window referred to … I doubt that any oil and gas company can rock up and apply for planning permission to survey, drill, think about it, and then frack in just a 16 week planning window.

    So my guess is that the ONR et al are waiting for a company to turn up and apply for planning permission before swapping paper.

    They can then comment on if and if it turns out to be for HPHV fracking then they can say they oppose it.
    They will not be holding their breath while waiting given the track record of South Western Energy, and the suspension of fracking in the Fylde. Although they may eagerly await the report from the Fylde.

    Why spend money to update a risk assessment for something that is not likely to materialise?

  2. Based upon the progress in France, Hinkley Point will happen after all the hydrocarbons in UK are long gone!!

    Besides which, the reactors seem pretty capable of engineering problems WITHOUT any seismic influence.

    But, that is what you risk when you need a desperate crutch for intermittent alternatives.

    Meanwhile, Drax to go ahead with new generation of electricity from ??? Yep-GAS.

    Good job Boris is trying to accelerate fusion.


  4. Well done to FFEQS for highlighting this important omission (or yet to happen analysis). The Fukushima disaster happened as a result of a massive natural earthquake and subsequent tsunami, which is not entirely unusual in that region of the world. While hindsight is always easy, shouldn’t the very real risk of that disaster occurring have been assessed more realistically prior to building it? The outcome and costs of the disaster suggest a resounding yes.
    While seismic risk around Hinkley Point is quite different, it will clearly be appropriate and necessary to take account of the known seismic risks from HVHF before any application to frack is approved in this location, particularly as the design and build standard has clearly not taken this risk into account, based on the FOI response.

    • Mike Potter

      I am sure the power station would assess the risks should a fracking application turn up. In the meantime, as there is none in sight ( I would discount the company mentioned above ), they can keep an eye on how the investigation goes for the Fylde. The results of that could help in any subsequent risk assessment, giving data that would not have been available prior to the events

      I suspect they would not support an application for HPHV fracking near the station.

      FFEQS would prefer that there is a ban on fracking ( or for all onshore oil and gas development as well ) with or without the nuclear power station, as Radiation Free Lakeland would also prefer an absence of nuclear power and fracking.

      Hence I would not see it as a gaping hole in the ( already written ) safety case, but, as ONS says, something to keep an eye on. The gaping hole is in the eye of the beholder.

      • hewes62. You say you suspect an application for HPHV frackingwould not be supported near Hinckley Point but I wouldn’t be too sure. PNR was approved despite being around 5 miles away from Springfields Nuclear Fuels, with Heysham Nuclear Power Stations not far away and permission having been given for the storage of 900 million cubic metres of gas in salt caverns planned to be made under the River Wyre about 6 miles away.

        • Pauline Jones

          Yes. That was then, but now there is more information available to them relating to the effects of fracking the shale in the Fylde and ( eventually ) the results of the OGA investigation to consider.

          • Let’s hope you are right if Cuadrilla were to become misguided enough to apply for planning permission once again after their permission expires in November. They have hinted that they will be. Possibly it’s just an attempt to keep investors on board but who knows?

  5. Largely agree Hewes. However, it’s invariably useful for articles like this to ensure that eye is keenly open and focussed though…. and nobody looking out for ships through the blind eye!

    • Mike


      Tho I expect both the project and existing power station have sight of the issue.

      Offshore safety Cases on onshore COMAH cases keep an eye out for issues.
      For example …

      Offshore wind farm proposals led to consultation with the WF developers and a review of helicopter flight risk and passing ship collision risk ( and out-with the safety case some thought about cable vs pipeline routing and how to handle revealed Old Unexploded Ordnance). Onshore looked at the effect of blade flicker on gas detection systems ( for an onshore wind farm ).

      The Management of Change system captured the information and actions. The regulator was not involved, as the onus is on the operator to take action and demonstrate they are on the ball.

      I expect the nuclear industry do likewise.

  6. Maybe they would do better at Hinkley getting funding to connect C to the grid?

    £717m required, only £637m agreed!

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