20. Dounreay, Caithness. (NC 982 667)

Dounreay with HMS Vulcan in foreground

The Vulcan Naval Reactor Test Establishment has taken part in nuclear submarine reactor tests since 1957. HMS Vulcan is operated by Rolls Royce for the MoD with a small Naval staff (currently five), who head up the organisation, and around 300 Rolls-Royce workers. Although commonly referred to as a civilian nuclear research plant, much the work carried out at Dounreay is done in conjunction with the military test establishment alongside it.

Nuclear reactors are tested at Vulcan before they are used in submarines, so that in theory, any problems that may have arisen in a particular design would have arisen at Vulcan long before they became a problem in an operational boat. The first reactor, designated Dounreay Submarine Prototype 1, or DSMP, also served as a full-scale training rig, allowing Royal Navy nuclear plant operators to gain hands-on experience. The 3rd DSMP core installed in 1974 and labeled Core Z, is fitted to the Royal Navy's current fleet of Trafalgar and Swiftsure "hunter-killer" class submarines.

Now designated PWR1, the first reactor plant for the British nuclear submarine programme was for Britain's Valiant and Resolution classes of nuclear submarines. It produced power for the first time in January 1965 at Vulcan. The final core designed for the PWR1 reactor was first manufactured during 1973 and commenced testing the following year. It is fitted in the current Swiftsure and Trafalgar class submarines.

PWR2 was manufactured in 1985 with testing at Dounreay commencing in August 1987. It is fitted to the current Vanguard class submarines and is the power plant for the new Astute class submarines due to replace the Swiftsure and Trafalgar class submarines.

Improvements in reactor design has culminated in the 'long-life core'. The first was manufactured in 1997/8 and began testing at Vulcan in 2002. Rolls Royce claim it has over six times the energy output and over four times the service life of the original PWR1 core. Long-life cores will be standard fit in the latest Astute class submarines, and back-fitted to the Vanguard class.

In 1987, LAIRD (Loss of coolant Accident Investigation Rig Dounreay) was commissioned at Vulcan which ran for five years and completed over 250 tests to reproduce the conditions in a nuclear reactor at the point of emergency shut-down. In recent years, LAIRD has been used to test the pumps from the nuclear reactors of HMS Spartan and HMS Trenchant whilst they were in refit.

Dounreay is also a possible site for the storage of low-level radioactive waste from the Interim Storage of Laid-Up Submarines (ISOLUS). Project ISOLUS was carried out by Lancaster University on behalf of the MoD. Final recommendations on ISOLUS will be made to the MoD in February 2004, and the results will be posted at www.isolus.org.uk/