A NEW reactor could be sited at Dounreay on the north coast of Scotland as part of the UK government's plans to replace the Trident nuclear weapons system over the next decade.

The submarines that will carry the warheads are planned to be powered by a new type of nuclear reactor. But before it goes to sea, it will have to be checked for safety and reliability at a land-based testing facility.

By far the most likely site for such an operation is the little-known Vulcan Naval Reactor Test Establishment, adjacent to the civil nuclear complex at Dounreay in Caithness. Vulcan has been the UK's only site for testing submarine reactors for more than 40 years.

The prospect of a new naval reactor in the north would be opposed by Scottish ministers and has been condemned by anti-nuclear campaigners, who fear an environmental disaster. Significantly, the Ministry of Defence (MoD) has not denied that Vulcan is in line for the development.

Owned by the MoD and run by the UK multinational Rolls Royce, Vulcan currently employs about 300 people. They conduct trials on the pressurised water reactors that drive much of the UK's military submarine fleet.

But the site's contract runs out in 2014, and it had been expected to be decommissioned. Now, however, it looks like it will continue for many years.

A spokesman for the Scottish Executive said: "The government's position is clear - we are against nuclear weapons being located anywhere in Scotland."

John Ainslie, co-ordinator of the Scottish Campaign for Nuclear Disarmament, said: "The prototype reactor for the new Trident submarines will use a novel design. If there was a major accident then a large part of the north of Scotland could be contaminated."

In a separate development, the MoD has revealed that the safety of the Trident nuclear warheads is currently being reviewed.

Scientists from the Atomic Weapons Establishment (AWE) at Aldermaston, Berkshire, are investigating the impact of changes in the way weapons are handled.