Office for Nuclear Regulation

Hinkley Point B gas plant incident 2009

Date released
4 April 2022
Request number


Release of information under
Freedom of Information Act 2000 (FOIA)

Information requested

“The Hinkley B gas plant incident 2009

I will like take a freedom of information request to disclose all official and unofficial reports or investigation reports including the plant investigation reports all emails sent or received by ONR or EDF , copies of all EDF internal reports including Saci reports and disciplinary actions that the ONR were aware off. In addition any other documents that were referred to as, part of the investigation.”

Information released

We confirm that under Section 1 of the FOIA, we hold information in scope of your request. We have identified information in 47 documents of which 14 we are releasing with redactions and are attached to this response. 33 have been withheld in their entirety.

Some of the information we are releasing contains correspondence between ONR and EDF, which was the subject of your previous FOI request to us dated 20 November 2021 (our reference: FOI202111033). Please be aware that ONR was established as a statutory Public Corporation on 1 April 2014 under the Energy Act (TEA) 2013. Investigations and other regulatory activities relating to licensed nuclear sites prior to 2014 were processed by ONR’s predecessor, the Nuclear Installations Inspectorate (NII) which was part of the Health and Safety Executive (HSE). Unfortunately, these documents were not identified in our searches for that earlier request due to how NII information held by ONR is stored and accessed. We apologise for this oversight.

Some of the information we are releasing includes the conclusions of our investigation and evidence of the subsequent work to address the issues raised in our enforcement letter dated 16 September 2009. This enforcement letter was released to you in your previous FOI request under the document title “2009.363316” (unique reference number: HPB71673R). 

Exemptions applied

30, 40

PIT (Public Interest Test) if applicable

Absolute exemptions

Section 40 FOIA – Personal information

In the 14 documents we are releasing, personal data has been redacted. This includes names, job titles, and contact details. We are also withholding five documents in their entirety as they consist solely of personal data such as National Insurance numbers, dose assessment reports, and a disciplinary interview. Release of each of this type of information could identify the individual either directly or indirectly. The personal data has been withheld using the exemption Section 40(2) of the FOIA.

In particular, release of the information would breach principle (a) of GDPR (lawfulness, fairness and transparency) on the grounds that there is no lawful basis to process this data. In addition, releasing this personal data would also breach principle (b) of GDPR (purpose limitation) as the data was provided incidentally over the course of email exchanges, or to substantively assist with the subsequent investigation after the event on 16 July 2009 at Hinkley Point B.

Furthermore, personal information relating to the health of third parties has also been removed. This type of information is more sensitive and is known as “Special Category Personal Data”. There are stronger legal protections against release of Special Category Personal Data which requires an Article 9 GDPR Condition for Processing. In our assessment, none of the grounds permitting the process of that data appears relevant here.

There is also personal information in some of the 33 documents not being disclosed, which would fall to be redacted in the event any of them were to be disclosed.

Qualified exemptions

As we set out in our earlier response to you on 21 February 2022 (our unique reference: 2022/1108), we have also considered the following exemption of the FOIA to 30 documents.

Some information is being withheld under the following sections of the FOIA:

Under Section 30(1)(b) of the FOIA, information held by a public authority is exempt if it has at any time been held by the authority for the purpose of ‘any investigation which is conducted by the authority and in the circumstances may lead to a decision by the authority to institute criminal proceedings which the authority has power to conduct.’

All of the information you have requested relates to an investigation carried out in 2009 regarding breaches of the Ionising Radiation Regulations 1999, which may have resulted in criminal proceedings and is therefore information within the scope of Section 30(1)(b).

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 disclosure:

Factors against disclosure:


Based on our assessment of the factors above, we have concluded that 28 documents of the requested information should be withheld entirely under Section 30(1)(b) FOIA. These documents relate to evidence gathered though the investigation process, internal ONR notes and draft communications, and reports relating to the investigation. The public interest favours non-disclosure as the requested information contains details which if released would adversely affect ONR’s ability to conduct future investigations and enforcement proceedings.

However, we recognise that there is a strong public interest in publishing the conclusions of our investigations as a regulator. We have therefore concluded that it is in the public interest that, out of the total 30 documents we considered under Section 30(1)(b) FOIA, two specific documents be released: the relevant Project Assessment Report (PAR) and the Dose Assessment Report. The PAR provides a summary of the incident and subsequent investigation, plus an evaluation of the event undertaken in accordance with the HSE/NII Enforcement Management Model in place at the time. The Dose Assessment Report is one of the key references for the PAR and sets out the calculations for the risk gap which sets the initial enforcement expectation. The release of these two documents is subject to redactions for personal information under Section 40(2) FOIA set out above.

Further Information

Please note that we only hold documents in line with our Business Classification Scheme and Disposal Schedule, some documents we may have previously held are no longer available as they have been destroyed.