One of the large buildings, is the prototype fast reactor - PFR, which operated for twenty years from 1974 - 1994.  It had the dual role of providing power to the grid and offering unique research and development facilities.  It provided information for the future design and operation of large commercial fast reactor stations and had an electrical output of 250 MW, which was enough electricity to supply a city, the size of Aberdeen.  Following the shutdown of the reactor in 1994, stage one of decommissioning began and is expected to be completed in 2008.  This will include the removal and disposal of the sodium coolant and preparation of the plant for several decades of care and maintenance before final demolition. A £17m plant called the Sodium Disposal Plant that will treat the sodium coolant has been built in what was the turbine hall.  Another alliance has been formed to clean up the pipe-work in the reactor.  This group is testing the techniques for this at a trials plant developed at Janetstown by one of the alliance members - JGC Engineering and Technical Services.