The aim of the Nordic BER-3 project has been to harmonize the Nordic intervention levels after a nuclear accident. The paper deals with the findings and recommendations to be presented to the Nordic authorities as background material for common decisions on the most likely protective actions. In the report sheltering, evaluation and relocation are treated in detail. Iodine prophylaxis and foodstuff restrictions are briefly commented on. The basis for this work is the internationally accepted basic principles for interventions.