Office for Nuclear Regulation

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HM Nuclear Installations Inspectorate

Quarterly statement of nuclear incidents at nuclear installations

A statement on incidents at nuclear installations in Britain which meet Ministerial reporting criteria is reported to the Secretary of State for Trade and Industry and the Secretary of State for Scotland and is published every quarter by the Health and Safety Executive.

For the period 1 April 2004 to 30 June 2004 there were 2 incidents at nuclear licensed installations that met the reporting criteria.

Hartlepool (British Energy)

On 9 June 2004 a flange leaked within the equipment used to handle tritrated water (i.e. water in which some of the hydrogen atoms are in the form of the radioactive isotope tritium) in the radioactive effluent treatment plant (RAETP) at Hartlepool power station. Approximately 900 litres of liquor were released. The station declared a site incident, which was stood down on 13 June after the affected areas had been restored to normal access conditions . During this time access to the affected area was controlled by the station to prevent unauthorised access to the contaminated areas and thus ensure that doses to workers were properly controlled.

The leak was retained within the bunded RAETP and discharged through authorized discharge routes, except for a small quantity, which escaped through evaporation. Assements by both station and the Environment Agency demonstrated that: a) doses to workers were only a small percentage of the annual limits; and b) the off-site dose was insignificant.

British Energy immediately set up a Divisional Panel of Inquiry and the details of the event and the lessons learned were promulgated to all sites. The Nuclear Installations Inspectorate and Environment Agency have conducted a joint investigation. The EA has advised station that it does not intend to prosecute. The NII is due to report shortly but is also expected to advise station that it will not prosecute.

Bradwell (Magnox Electric)

On 14 April 2004 there was a release of radioactivity in the reactor building at Bradwell Power station operated by Magnox Electric plc.

The incident occurred while preparations were being made to lower a camera into the reactor which was to be used to observe some modified equipment for Defueling. The operation involved opening a set of valves and the wrong valve was opened which lead to the release because unexpectedly the reactor was under pressure. The contamination alarm sounded but there was some delay before the area was evacuated.

6 members of staff received small doses of radiation below legal limits. The incident is still under investigation by NII.

Single copies of statements are available free from the Health and Safety Executive, Nuclear Directorate, Division 4a, Building 4 NG1, Redgrave Court, Merton Road, Bootle, L20 7HS,