Plan to clear waste from nuclear reactor shaft

Old laboratory coats and centrifuges, stainless steel tubes, canned radioactive strontium, lead bricks, empty boxes are all in the Dounreay Intermediate Level Waste shaft - along with amounts of highly radioactive materials. The experts' advice is get it out.

The UK Atomic Energy Authority (UKAEA) is waiting for the Department of Trade and Industry to approve an ambitious plan which would end growing fears of a second explosion in the Dounreay fast breeder reactor's disposal shaft.

Among the most popular suggestions is one that the water-filled shaft, 65.5m (215ft) deep, should be frozen, and the contents - reportedly including enriched uranium and plutonium - lifted and removed.

This suggestion, from an international consortium led by the nuclear engineering company Dames & Moore, is the most radical, yet logical, on the table. It would mean that the relative positions of waste in the shaft would change minimally. That would reduce the risk of an explosion that could otherwise scatter radioactive material over a huge area of the Scottish coast.

The simple alternative, of sealing the shaft, would be cheaper in the short term. But in the long term it carries the severe risk of leaking radioactive material into the water table and the sea, as water permeates into the shaft.

Either option will take up to 20 years and cost several hundred million pounds, said a spokesman for the UKAEA yesterday. He declined to say whether the UKAEA had suggested removal or sealing, but independent experts agree that removal is far more sensible than leaving the waste there. A study in 1994 by AEA Technology, an independent consultancy, concluded that "doing nothing is not an option".

The material crammed into the shaft has already exploded once - on 10 May 1977. The explosion had such force that a concrete plug 24 metres from the bottom was blown up the shaft, where it broke through the concrete cover, showering the adjacent beach and area with radioactivity.

Removing the waste, which consists of a haphazard collection of contaminated items and radioactive sources dumped since the shaft was dug in 1955, would be financially more expensive, but far safer in the long term.