Sellafield 'drip' upgraded

15 May 2009

A slow leak of radioactive liquid discovered in January at the UK's Sellafield site has been upgraded to Level 2 on the International Nuclear Event Scale.

Sellafield in 2004 (Sellafield Ltd)

Sellafield, as the site looked in 2004 (Image: Sellafield Ltd)

Drips of liquid were observed from a valve flange on a condensate drain line from a ventilation duct serving the Magnox fuel reprocessing plant in January 2009 - coincidentally, the same day that the country's prime minister Gordon Brown visited the site and announced its inclusion in the list of possible sites for nuclear new build. The liquid was of very low radioactivity but about 2 cubic metres of the concrete slab surface it dripped on to was subsequently found to be contaminated.
According to information posted on the Nuclear Events Web-based System (NEWS) - run jointly by the International Energy Agency (IAEA), OECD Nuclear Energy Agency (NEA) and World Association of Nuclear Operators (WANO) - the drip was quickly contained and no personnel were contaminated. The event was initially rated at Level 1 (an 'anomaly') on the International Nuclear Event Scale (INES), but this has now been upgraded to INES Level 2 ('incident') because of the total amount of contamination which accrued over a period of time.
Reports in the UK media suggest that the leak had in fact gone undetected for 14 months, leading to calls from local anti-nuclear group Cumbrians Opposed to a Radioactive Environment (CORE) for Sellafield Ltd to be prosecuted. In April 2005, a more serious leak of radioactive liquid was discovered at the Thorp reprocessing facility, also at Sellafield, culminating in the operator at the time, BNGSL, facing a £500,000 ($760,000) fine.