Office for Nuclear Regulation

Statement of civil incidents meeting the Ministerial Reportable Criteria (MRC) reported to ONR - Q2 2017

01 April  2017 to 30 June 2017

A statement on incidents at nuclear installations in Great Britain and during the transport of radioactive material, which meet Ministerial Reporting Criteria (MRC), is provided to the Secretary of State for Business, Energy and Industrial Strategy and the Secretary of State for Scotland and Wales, and is published each quarter by the Office for Nuclear Regulation.

For the period, 01 April  2017 to 30 June 2017, there was one incident which met the MRC.

Sellafield Ltd – Spillage of Uranium sample during routine laboratory operations which exceeded reporting criteria - 14 June 2017

Ministerial Reporting Criterion - Abnormal occurrences leading to a release or suspected release or spread of radioactivity, on or off site, which requires special action or special investigation by the Operator.


A routine material transfer operation was being undertaken in a laboratory in a radiation controlled area. During the operation a small polythene bottle containing depleted Uranium Trioxide (UO3) powder was dropped by an operator, resulting in approximately half of its contents spilling onto the laboratory floor. The amount of material spilled exceeded the reporting requirements under the Ionising Radiation Regulations 1999.

The licensee, in accordance with its emergency instructions, evacuated the area and conducted health physics monitoring checks of the operator and laboratory. Radiation monitoring equipment in the area close to the spill did not go into alarm, indicating the material remained a solid substance and did not spread beyond the immediate area. The physical nature of the material means the main health risk arises from ingestion or inhalation.

Immediate monitoring of the operator showed that there was no personal or skin contamination; the contamination was limited to their laboratory clothing only.  There was no evidence that ingestion or inhalation had occurred.

The laboratory area affected has now been decontaminated, and the licensee has instigated a management investigation.

ONR considers the licensee’s initial response to the event to be acceptable.  The licensee’s management investigation is ongoing and ONR will review its findings on completion.  ONR will undertake follow up enquires to confirm the adequacy of the licensee’s actions to minimise the likelihood of a similar event occurring in the future.