Office for Nuclear Regulation

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Hinkley Power Station & Seismicity

Date released
3 October 2019
Request number
201909026
Release of information under
Freedom of Information Act 2000

Information requested

  1. Please provide me with any information held by ONR in relation to Hinkley Point Nuclear Power Station facility and review or planned review of the Probabilistic Seismic Hazard Assessment from potential oil and gas exploration or development activities, including wastewater disposal.
  2. Please can you provide me with any correspondence relating to issues raised by any of the following parties in relation to potential petroleum exploration and development activity in the vicinity of Hinkley Point Power Station:

    2a. ONR - OGA

    2b. ONR - Licensee

    2c. ONR - Somerset County Council

    2d. ONR - any representative of South Western Energy Ltd, Transgas Ltd or Infinity Energy Ltd

  3. Given that EDF has recently announced that a major milestone will be reached during 2019 when the 4,500 tonne concrete platform that will form a base for the reactor buildings will be complete, please provide me with the following information relating to further work to be completed by NNB Genco, or other contractors, subsequent to the findings contained within Hinkley Point C Pre-Construction Safety Report 2012 – Assessment Report for Work Stream B7 External Hazards. Recommendations:

    3a. Page 27 para 104 “The Licensee shall complete the seismic hazard forward work programme to confirm the seismic design basis to be used for plant design before end December 2014.” And page 38 Table 3 UK EPR GDA Assessment Findings Relevant to External Hazards Office for

    3b. AF-UK EPR-CE-020 The Licensee shall ensure that due regard is taken of the effects of Structure- Soil Structure Interaction in the seismic analysis of the Class 1 and 2 structures. (Milestone: First structural concrete)

    3c. AF-UK EPR-CE-029 The Licensee shall demonstrate the suitability of the equivalent lateral load method for the application of seismic loads to Seismic Class 1 and 2 structures if this approach is used. (Milestone: Nuclear island safety related concrete)

    3d. AF-UK EPR-CE-030 The Licensee shall demonstrate the stability of the NAB in terms of sliding and overturning under seismic loading. (Milestone: Nuclear island safety related concrete) http://www.onr.org.uk/hinkley-point-c/pre-construction-reports/onr-cnrp-ar-13-108-external-hazards.pdf

Information released

We have addressed each of your specific requests in turn below.

  1. With respect to Question 1, 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.
  2. Regarding Question 2, 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.
  3. In relation to Question 3, the Seismic Hazard forward programme of work has been completed resulting in a new PSHA study for the HPC site being produced. Further information regarding this study can be found in the open literature as follows:
    1. Aldama-Bustos, G., Tromans, I. J., Strasser, F., Garrard, G., Green, G., Rivers, L., ... Robertson, C. (2019). A streamlined approach for the seismic hazard assessment of a new nuclear power plant in the UK. Bulletin of Earthquake Engineering, 17(1), 37-54. https://doi.org/10.1007/s10518-018-0442-5
    2. Lessi-Cheimariou, A., Tromans, I.J., Rathje, E. et al. (2018), Sensitivity of surface hazard to different factors and site response analysis approaches: a case study for a soft rock site, Bulletin of Earthquake Engineering (2019), 17: 73. https://doi.org/10.1007/s10518-018-0446-1

Concerning the other recommendations highlighted in your request (3a, 3b, 3c & 3d); these have been closed via ONR’s assessment activities that culminated in ONR’s assessment of a request by NNB GenCo (HPC) Ltd for Consent to commence unit 1 nuclear island concrete. Further information may be found in the relevant Project Assessment Report available on the ONR website.

Exemptions applied

N/A

PIT (Public Interest Test) if applicable

N/A