ENGLAND: INCIDENT IN SELLAFIELD WVP AREA
The UK Nuclear Installations Inspectorate (NII) has said that there was an incident at the Sellafield plant on the 19th of September 2008. The information comes in the quarterly report issued by the NII Chief Inspector forwarded to the Celtic League.
The incident took place in the Waste Vitrification Plant. The NII say the cause of the incident has not yet been established. They also indicate they are considering enforcement action.
The Windscale Vitrification Plant, which was opened in 1991, is used to seal high-level radioactive waste in glass. In the plant, liquid wastes are mixed with glass and melted in a furnace, which when cooled forms a solid block of glass for on site storage. The statement from the NII and the covering letter from the Chief Inspector are set out below:
«A statement on incidents at nuclear installations in Britain which meet Ministerial reporting criteria is reported to the Secretary of State for Energy and Climate Change and the Secretary of State for Scotland. It is published every quarter by the Health & Safety Executive.
For the period 1 July 2008 to 30 September 2008 there was one incident at a nuclear licensed installation that met the reporting criteria.
Sellafield
On 19 September 2008 a fault occurred on the radioactive Waste Vitrification Plant (WVP) Line 3 shield door interlock system. Nobody was injured or received any radiation dose.
During a planned changeover of hydraulic supply units in Line 3, an uncontrolled movement of two shielded trap doors and other hydraulically-drive components was observed. These components protect against the inadvertent exposure of workers to radiation and so are designated Safety Mechanisms.
One movement was of the trap door between the Line 3 Control Cell and Decontamination Cell. Neither cell was occupied at the time, though personnel access to these cells is permitted and it is possible for personnel to be working in one cell while a container of vitrified waste is present in the other. The radiation dose rate from a container of vitrified waste is very high and hence the incident had the potential to cause a significant radiation dose.
The root cause of the incident has not yet been established and is the subject of ongoing work by Sellafield Limited. Meanwhile Sellafield Limited has suspended all of Line 3 shield door operations.
NIl is investigating the incident taking into consideration the implications for safe operation of other facilities at the Waste Vitrification Plant, and also the implications of previous shield door incidents. Nil is considering enforcement action»
«STATEMENT OF NUCLEAR INCIDENTS AT NUCLEAR INSTALLATIONS
I enclose the statement of nuclear incidents at nuclear installations for the period 1 July to 30 September 2008. During this quarter there was one incident at a civil licensed nuclear installation that met the Ministerial reporting criteria. The statement will be published in the week commencing 10th November 2008. As always, I am available to discuss this report or other matters relating to the safety of the UK nuclear industry or its regulation.
Yours sincerely
Mike Weightman HM Chief Inspector of Nuclear Installations and Director, Nuclear Directorate, Health and Safety Executive»
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J B Moffatt Director of Information Celtic League 12/11/08
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