Sellafield HLW Tank ‘Near Miss’

Marianne Birkby

The High Level Liquid Waste (HLLW) stream at Sellafield is fiercely radioactive – so much so that it is self-heating and needs to be constantly cooled. This is achieved by a system of pipework inside the HLLW tanks which carry cold water.

It is important that the cooling system in the high level waste tanks is kept running constantly – otherwise the high level wastes in the tank could get so hot that they boiled. If the cooling problem was still not sorted out, the tank would eventually boil dry.



It is very important to prevent this happening – because if the wastes were allowed to start boiling then radioactivity would escape and contaminate the surroundings. The timings involved are very short. BNFL analysis has indicated that cooling failure would lead to boiling after 12 hours, and to the tank drying out after three days.

On Wednesday 1st April, the Sellafield Site Newsletter ‘Sellafield News’ reports that there was a loss of cooling to the HLLW tanks that lasted for up to eight hours and involved the site Emergency System for four hours. Clearly the times involved – four hours and eight hours are worryingly close to the timings that would have resulted in a release of radioactivity. The Nuclear Installations Inspectorate (NII) have stated that the consequences of prolonged cooling failure (up to three days)
could be ‘very severe’.

Ironically, this incident happened just a week after the Norwegian Radiation Protection Authority published a report comparing the effects of an accidental release of radioactivity from the Sellafield high level waste tanks to the effects of the Chernobyl accident. This report refers to the implications of an accident at Sellafield being up to 50 times worse than Chernobyl (see page 5) – obviously, because Sellafield is in Cumbria, the effects on Cumbria and the UK would be much worse.

The NDA were set up to look after nuclear wastes and reduce risks to Cumbria and the wider international community. Why have the Nuclear Installations Inspectorate’s urgent safety recommendations been ignored? Will Cumbrian Councillors hold the NDA to account?

Yours sincerely
Marianne Birkby
On behalf of Radiation Free Lakeland