Watercolour on Paper. Signed.
William Heaton Cooper was perhaps the quintessential painter of Lakeland landscapes and this picture appears to be a one-off, possibly painted as a Commission for the UKAEA.
BEPO was the first research reactor of significant power in the UK. It was commissioned in 1948 and used primarily for the production of radio-isotopes and neutrons for nuclear measurements. It was used to demonstrate that commercial nuclear power reactors could be viable and was a forerunner of Windscale. It was closed in 1968.