Another radioactive particle has been found on a beach in northern Scotland, close to the Dounreay nuclear plant.

It is the twelfth particle to be found there since 1983. Nine of the particles have been discovered in the last 12 months.

The plant's operators, the United Kingdom Atomic Energy Authority, say the risk to members of the public is low.

But anti-nuclear campaigners want the beach to be closed to prevent anyone coming in contact with similar particles.

The most recent find is described as a small speck of irradiated metal, about the size of a grain of sand, and similar to the 11 found previously.

Reassuring

They were produced by operations several decades ago at Dounreay, which was intended to develop fast reactor technology.

Sandside is open to all A UKAEA spokesman said: "Independent studies have shown that the possibility of a member of the public coming into contact with a particle is extremely low. We take the particles very seriously."

The owner of Sandside beach, Geoffrey Minter, said three months ago that fewer than 3% of the particles on his land were being found by the monitoring.

He was speaking after commissioning an independent report into the safety of the beach.

Andrew Munn of UKAEA told BBC News Online: "We monitor the whole beach every month. We've asked Mr Minter for his report, but we haven't seen it yet."

Farcical

Mr Minter told BBC News Online: "I have asked the company which compiled the report to prepare an executive summary, and I shall be making that publicly available within the next two weeks."

Kevin Dunion, Scottish director of Friends of the Earth, said: "This is rapidly becoming a farce. Month after month these particles are turning up on this beach, and it really is about time UKAEA were relieved of their duties.

Geeoffrey Minter has commissioned a report into the safety of the beach "Although the risk to the public is minimal, these are deadly particles, and we should be minimising the risk.

"That means the public should be denied access to that beach. We can't play fast and loose with these particles."

In March this year, the UKAEA was fined £101,000 after admitting responsibility for the contamination of three workers at the Caithness plant and an incident in which a mains electricity cable was severed.

The second incident prompted the most fundamental review of safety at the plant in its 40-year history. It resulted in a damning report with 143 separate recommendations for improving operating procedures at Dounreay.

It also prompted the UK Government to halt all foreign imports of radioactive waste for reprocessing and to shut down the entire fuel recycling area.