Russian nuclear store – a powder keg.

Scientists have identified a risk of an “uncontrolled chain reaction” at one of the world’s largest radioactive waste stores in northern Russia.

According to environmentalists, this could trigger a disaster worse than the accident at the Chernobyl nuclear plant in 1986. But the probability of such a disaster is regarded as very small by regulatory authorities.

“We are sitting on a powder keg with a burning fuse,” claims Alexander Nikitin, from the St Petersburg office of the Norwegian environmental group, Bellona. “And we can only guess about the length of the fuse.”
Andreeva Bay, on the Kola Peninsula in northwest Russia, is home to 21,000 spent uranium fuel assemblies from nuclear submarines and ice-breakers. But the three huge concrete tanks in which the radioactive waste is stored have begun to corrode and let in seawater.
Critical mass

A study by scientists from three Russian research institutes suggests that salt water could accelerate disintegration of the fuel, splitting it into tiny particles. If the particles reach concentrations of 5-10% in water, it could be dangerous, they say.
“Calculations show that the creation of a homogeneous mixture of these particles with water could lead to an uncontrolled chain reaction,” they warn. This kind of accidental critical mass, leading to bursts of radiation and heat, is a well-recognised risk in the nuclear industry, but is not the same as a nuclear explosion.

New Scientist