Much of the town is a planned 19th-century development. In 1906, a new Royal National Lifeboat Institution boathouse and slipway was inaugurated near Scrabster Harbour. A fire on 10 December 1956 destroyed the building and its 47ft Watson-class lifeboat and a new building and boat was built, launched the following year. A new lifeboat, named "The Three Sisters" was inaugurated in 1971 by The Queen Mother. A major expansion occurred in the mid-20th century when the Dounreay nuclear power plant was established at Dounreay in 1955, to the west of the town. The arrival of workers related to the power station caused a three-fold increase in the population of Thurso; the 1951 census gave a figure of 3,000 but this had swelled to 9,000 by 1971. This led to around 1,700 new houses being built in Thurso and nearby Castletown, a mixture of local authority housing blended with private houses and flats built by the United Kingdom Atomic Energy Authority. Decommissioned at the end of the 20th century, it is estimated the site will not be cleared of all the waste until the 2070s, so will continue to provide employment.