contract, ending in the creation of a "brownfield" site, which would be transferred to the Nuclear Decommissioning Authority. This decommissioning programme would start in 2023, following the removal of all fuel to the NDA Sellafield site. Dounreay Submarine Prototype 1 (DSMP1) The first reactor, PWR1, is known as Dounreay Submarine Prototype 1 (DSMP1). The reactor plant was recognised by the Royal Navy as one of Her Majesty's Submarines (HMS) and was commissioned as HMS Vulcan in 1963. It went critical in 1965. HMS Vulcan is a Rolls-Royce PWR 1 reactor plant and tested Cores A, B and Z before being shut down in 1984. In 1987, the plant was re-commissioned as LAIRD (Loss of Coolant Accident Investigation Rig Dounreay) a non-nuclear test rig, the only one of its kind in the world. LAIRD trials simulated loss of coolant accidents to prove the effectiveness of systems designed to protect the reactor in loss-of-coolant accidents. Shore Test Facility (STF) The second reactor, PWR2, is housed in the Shore Test Facility (STF), was commissioned in 1987, and went critical with Core G the same year. The plant was shut down in 1996, and work began to refit the plant with the current core, Core H, in February 1997. This work was completed in 2000 and after two years of safety justification the plant went critical in 2002. Vulcan Trials Operation and Maintenance (VTOM) (the programme under which Core H is tested) was completed and the reactor shut down on 21 July 2015. The reactor will be de-fuelled and examined, and post operational work will continue to 2022. The site would then be decommissioned along with facilities at neighbouring UKAEA Dounreay. In January 2012, radiation was detected in the reactor's coolant water, caused by a microscopic breach in fuel cladding. This discovery led to being scheduled to be refuelled and contingency measures being applied to other Vanguard and Astute-class submarines, at a cost of £270million, before similar problems might arise on the submarines. This was not revealed to the public until 2014. See also Nuclear power in Scotland Atomic Energy Research Establishment Nuclear power in the United Kingdom Energy policy of the United Kingdom Energy use and conservation in the United Kingdom RAF Dounreay References External links Dounreay Site Restoration, official website Dounreay - Future Plans, NDA Shore Based Testing, Rolls-Royce Marine Vulcan leads the way for Navy nuclear reactors, Navy News, 7 January