Office for Nuclear Regulation

Statement of nuclear incidents at nuclear installations

A statement of nuclear incidents at nuclear installations in Britain during the fourth quarter of 2000 is published today by the Health and Safety Executive (HSE). It covers the period 1 October to 31 December 2000 (copy below).

The statement is published under arrangements that came into effect from the first quarter of 1993, derived from the Health and Safety Commission's powers under section 11 of the Health and Safety at Work etc. Act 1974.

'Statement of Nuclear Incidents at Nuclear Installations: Fourth Quarter 2000' - single copies are available free from the Information Centre, Nuclear Directorate, HSE, Room 004, St Peter's House, Stanley Precinct, Bootle L20 3LZ


1. The arrangements for reporting incidents were announced to Parliament by the Parliamentary Under Secretary of State for Energy on 30 April 1987 (Hansard col. 203-204). A minor modification to arrangements for reporting on nuclear incidents was announced in HSE press notice E108:93 of 30 June 1993.

2. Normally each incident mentioned in HSE's Quarterly Incident Statements will already have been made public by the licensee or site operator either through a press statement or by inclusion in the newsletter for the site concerned.

3. The location of the installation mentioned in the statement is:

Sellafield (British Nuclear Fuels plc)


The Health and Safety Executive presents the attached statement of nuclear incidents at nuclear installations published under the Health and Safety Commission's powers derived from section 11 of the Health and Safety at Work etc. Act 1974.

INCIDENT 00/4/1 - SELLAFIELD (British Nuclear Fuels plc)

A loss of electrical supplies to a large portion of the Sellafield site was experienced during Monday 9th October 2000. The failure centred on faults experienced on a new section of 11kV switchgear. Supplies were re-established within 47 minutes of the loss, well within the two hours allowed for in the safety case.

The actions of BNFL during the recovery phase from the incident were found to be generally commendable, ensuring reinstatement of electrical supplies to the affected area well within the time allowed in the safety case.

An NII team carried out an initial investigation into the incident. It concluded that the direct cause was a defective component in new electrical switchgear being installed as part of a project to update the electrical infrastructure on the site. The work was being carried out by Norweb, as contractors to BNFL, to arrangements that were regarded as standard practice for this sort of work.

BNFL also carried out an investigation, which came to similar conclusions. This report is still formally awaited by NII, although there has been sufficient progress in satisfying NII's safety concerns with respect to the electrical infrastructure at Sellafield.

The incident was classified as Level 1 on the International Nuclear Events Scale (INES).