Changes to 74/642/Euratom: Council Decision of 17 December 1974 adopting a research and training programme for the European Atomic Energy Community on plutonium recycling in light-water reactors (indirect nuclear projects)
EU Decision 1974/642
Made by 78/843/Euratom: Council Decision of 10 October 1978 amending Decision 74/642/Euratom adopting a research and training programme for the European Atomic Energy Community on plutonium recycling in light-water reactors (indirect nuclear projects)
From legislation.gov.uk's record of changes, the official one: see it there.