Office for Nuclear Regulation

Statement of Nuclear Incidents at Nuclear Installations - Q3 2013

A statement on incidents at nuclear installations in Britain, which meet Ministerial Reporting Criteria (MRC), is provided to the Secretary of State for the Department of Energy and Climate Change and the Secretary of State for Scotland, and is published each quarter by the Office for Nuclear Regulation (ONR), an Agency of the Health and Safety Executive (HSE).

For the period 1 July 2013 to 30 September 2013, there was one incident at a licensed nuclear installation, which met the MRC and the report is published below.

ONR completed a system inspection against the requirements of two Licence Conditions (LC) within two facilities on the Dounreay site in mid July 2013. This inspection concluded that there were weaknesses in how the limits and conditions derived from the facility safety cases had been implemented into working instructions. ONR wrote to the licensee on 16 August 2013 requiring them to investigate these findings and to assess the extent of any potentially similar non-compliances in other facilities on site.

The licensee subsequently confirmed that ONR's assessment was accurate and that the scope was potentially site wide. The Dounreay Site Restoration Limited (DSRL), Managing Director took the conservative decision to stop operations on 14 August 2013 on the higher category facilities until he was satisfied they were compliant with the requirements of the (LC).

The licensee immediately commenced a formal investigation, which is now complete and was submitted to ONR on 8 October 2013. The preliminary findings from the licensees investigation have identified a number of causes and actions to help prevent a recurrence. An action plan has been generated which is expected to be complete at the end of November 2013.

ONR has reviewed, and is content with, the actions already taken by DSRL, and further inspection is planned in this respect in November 2013 to confirm the adequacy of the improvements made. On receipt of the DSRL investigation report ONR will review it and then decide what, if any, further regulatory action to take, which could include a formal investigation.

The event has been provisionally rated by the licensee as INES level 0, although as it represents a failure of safety provisions but with significant defence in depth remaining, the INES National Officer was consulted, and he indicated that it may finally attract a rating of 1 on the 7 level scale; an anomaly.

There have been no injuries to workers or releases to the environment, as a consequence of the event.