The European Commission has published its first annual progress report on its specific programme in the area of nuclear fission safety (1990-1994). This report covers the period from December 1992 to November 1993 and looks at the research work and activities developed under the this programme during this period. Activities financed under the Nuclear Fission Safety (or reactor safety) programme concentrate on the confinement of radioactivity under severe accident conditions and are executed in the form of a reinforced concerted action with multi-partner contracts and a limited financial contribution from the Commission (about 20% on average of the total budget). The overall aim is to develop consensus at Community level on outstanding problems and how to solve them. The work programme covers the following research areas: - Core degradation progression; - Hydrogen related problems; - Molten fuel/coolant interaction; - Reactor pressure vessel response; - Molten core/concrete interaction; - Source term (fission products behaviour); - Containment response under severe accident conditions; - Accident management support. The report details the objectives of the programme in each of these eight areas, the working plan and a progress review of the activities carried out in the period from December 1992 - November 1993.