Office for Nuclear Regulation

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Sellafield "security events"

Date released
26 July 2019
Request number
Release of information under
Freedom of Information Act 2000

Information requested

I would like to request a list of the security events including:

If possible I would also like to request a copy of the documents compiled by Sellafield Ltd as a result of their security investigations.

If there are exemptions that apply to any of these requests, I would appreciate it if you could still send me the elements of my request that exemptions do not apply to.

Information released

ONR applied regulatory attention to the effectiveness of Sellafield Ltd.’s investigation into six security events within reporting year 2017/18. I can confirm that the ONR holds information of the description in your request. However, we are refusing your request under Section 24; safeguarding national security of the FOIA.

As this is a qualified exemption, we are required to balance the public interest between disclosure and non-disclosure. We have therefore applied the Public Interest Test, as set out below.

Factors for release

Issues related to the nuclear industry are subject to close scrutiny and debate, there is a public interest in information related to nuclear activities and the release of such information. The information may provide reassurance to the public about the safety of nuclear installations. It may also facilitate the accountability and transparency of ONR for decisions taken by them as a regulator and enforcing authority of the nuclear industry.

Factors for withholding

Information that relates to the purposes of safeguarding national security and which may be of use to terrorists and other hostile actors is exempt from disclosure. The specific details of these events could provide an adversary with information that enables them to develop intelligence which may help them defeat security arrangements. Paragraph 13 of Section 24(1) makes it clear that there need be no evidence that an attack is imminent for this exemption to be applied.


After careful consideration of the factors set out above, ONR has concluded that the information should be withheld. On balance, the interests of national security outweigh the need for openness in terms of the specific information that you have requested. Therefore, it is ONR’s judgement that publication of the information requested would not be in the public interest.

As an independent regulator we endeavour to be as open as transparent as possible and we appreciate it may be disappointing that we have been unable to provide the full information requested. In the spirit of trying to be as helpful as possible, I can tell you that none of the incidents was considered to be of sufficient gravitas to require any formal enforcement action. As referenced in our Annual Report and Accounts, our regulatory attention focussed on the effectiveness of Sellafield Ltd.’s investigations into these incidents, as opposed to the incidents themselves. You may also wish to know that the security events in question, in isolation and in aggregation, did not undermine the overall effectiveness of security or safety at Sellafield.

Exemptions applied

Section 24.

PIT (Public Interest Test) if applicable