Office for Nuclear Regulation

Statement of nuclear incidents at nuclear installations - Q1 2012

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, an Agency of HSE.

For the period 1 January 2012 to 31 March 2012 there were two incidents at licensed nuclear installations, which met the MRC, and reports are published below.

URENCO UK Limited Capenhurst 22 February 2012

ONR was promptly notified of a fire in a non radiologically contaminated solvent degreaser tank, located within a pump maintenance workshop, at one of the enrichment facilities. There were no injuries to personnel and the public were not affected. Monitoring of the perimeter of the site confirmed that there was no significant release of radioactive material. The non-radioactive degreaser solvent fire led to evacuation of the enrichment facility control room for about an hour. The fire was extinguished by the licensees on site Fire & Rescue team, supported by Cheshire Fire & Rescue Service, as rehearsed during planned ONR observed emergency exercises. Other aspects of the licensees emergency arrangements generally worked well, with only minor improvements now being implemented. As a fire on a nuclear licensed site, both ONR and the licensee made reports to the relevant Government Ministers.

The ONR nominated site inspector inspected the facility affected the next day, and ensured that the licensee had initiated a sufficiently scoped investigation, (a Board of Inquiry). The licensees subsequent Board of Inquiry report has now been shared with ONR and assessed by ONR as being appropriately comprehensive, with follow up actions identified for implementation in a timely manner. ONR has determined that enforcement action was not appropriate. This is on the basis that the licensee has taken prompt action to implement a more robust maintenance regime and to obviate the build up of oil and grease residues within the heated solvent degreaser tank. These were understood to have been a key root cause of this event. Improvements to fire risk assessments have also been initiated. ONR will continue to inspect the licensees implementation of other actions identified by the licensees Board of Inquiry.

This event has been given a rating of 'Below Scale / Level 0' on the IAEA INES scale.

Sellafield Limited Capenhurst Works 28 February 2012

During planned site decommissioning operations, a quantity of historical uranium contaminated water and sludge was found in a radiologically controlled area that was recently undergoing decommissioning clean up operations. The spillage was contained within concrete service channels, which were underneath steel plate covers.

Detailed analysis of the water and sludge was promptly conducted, in order to confirm the actions required to safely remove the material. The analysis indicated that the contamination found exceeded the quantity specified in IRR 1999 Schedule 8. This quantity was therefore regarded as significant under these regulations and, as such, was reportable to Government, under the sites reporting arrangements.

There has been no injury or damage, no significant release of radioactive material, there was no potential for any off-site hazard and the public were not affected.

The ONR nominated site inspector, a specialist ONR inspector and the Environment Agency site inspector jointly inspected the scene of the event, in response to the prompt notification by the licensee. ONR has provided the Licensee with regulatory advice to inform their investigation, which is currently nearing completion. ONR is content that the scope of the investigation is sufficiently wide ranging. Interim investigation reports have been provided by the Licensee and ONR will continue to monitor the implementation of the investigation recommendations. ONR is content with the Licensees prudent response to the event and no further regulatory action is planned, other than following up implementation of investigation actions by the Licensee.

This event has been given a rating of 'Below Scale / Level 0' on the IAEA INES scale.