Sellafield glows in the dark again

http://www.aftenposten.no/english/local/article1035400.ece
20 Tonnes of uranium solution has leaked in Sellafield apparently enough to make 40 bombs ! With no way of cleaning up , it could be a problem .
Years ago I went to a meeting about nuclear power station building proposal. One of the objections , not denied, was that there had been and was an ongoing leak on one of the storage tanks at Sellafield which they couldnt stop, but as they said, it couldnt get into the water table and was contained within Sellafield, it was ok ...
20 Tonnes is neither a lot nor a little when it comes to storage tanks its only a petrol tanker full, so it is unlikely that an entire tank drained. Yet it would take a small leak a long time to do 20,000 litres [ish]. I think the geiger counters in Sellafield would have noticed it rather quickly .
I wonder if its the same leak - and they have just decided to publicize it ? and possibly downplayed the quantity maybe ? Its a long time ago , but i seem to recall the quantity as 1000 gallons [ 4,500 litres].