Office for Nuclear Regulation

Quarterly statement of nuclear incidents at nuclear installations - Q2 2011

A statement on incidents at nuclear installations in Britain which meet Ministerial Reporting Criteria (MRC) is reported to the Secretary of State for the Department of Energy and Climate Change and the Secretary of State for Scotland and is published every quarter by the Health & Safety Executives ONR.

For the period 1 April 2011 to 30 June 2011 there were no incidents at licensed civil nuclear installations that met the MRC.

For the period 1 January 2011 to 30 March 2011 we said there was one incident that could meet the MRC. The incident occurred at the Sellafield site and is now considered to meet the criteria; an update is provided below.

Sellafield Ltd

In February 2011, a pre-operation radiological survey was requested due to the proposed use of an area for lay-down purposes during maintenance work on the main building extract fans serving the Analytical Services Laboratories. During the area survey significant levels of surface contamination were detected, which were hitherto unknown. Subsequent additional surveys and analysis confirmed that the total radioactivity in the ground exceeded the quantity for notification in Column 4 of Schedule 8 in the Ionising Radiation Regulations. The detailed analysis has also given reassurance that the material was of the order of decades old. Furthermore it should be noted that despite extensive investigations by Sellafield Ltd no obvious source or leak path has been identified to date. Sellafield Ltd has concluded that the most appropriate ALARP approach is to record the presence of the contamination and seal the surface to prevent its spread, and then periodically to monitor the situation for migration of material. Remediation of the contamination will ultimately be undertaken through the Sellafield Site Ground Remediation Project. ONR has accepted that the proposed way forward by the operator is reasonable.

Single copies of statements are available free from the Health and Safety Executive, Office for Nuclear Regulation, Division 3, Building 4.N2, Redgrave Court, Merton Road, Bootle, L20 7HS,