All EU Member States are represented in ENSREG by senior officials from their national regulatory authorities or nuclear safety authorities. Senior representatives of the European Commission are also part of the group. In addition, Council of the European Union, Switzerland, Norway, and the International Atomic Energy Agency, have observer status in the group.

Nuclear safety and the safe management of spent fuel and radioactive waste is a national responsibility, exercised by ENSREG’s members in their own countries to agreed international minimum safety standards. Decisions concerning safety actions and the supervision of nuclear installations remain solely with the operators and national authorities. ENSREG was initiated in 2007 when following the Commission proposal, the European Council (pdf) endorsed the establishment of a high-level group at EU level aimed at furthering a common approach where this could add value to the safety of nuclear installations, the safety of the management of spent fuel and radioactive waste and the financing of the decommissioning of nuclear installations. This proposal received full support of the Council of the European Union and the European Parliament. On 17 July 2007, the Commission by its Decision established the European High Level Group on Nuclear Safety and Waste Management, later renamed as ENSREG by the Group's Members.

The fundamental principle of ENSREG’s work is that there should be continuous improvement in nuclear safety. Striving for continuous improvement is a vital safeguard against complacency in the important area of nuclear safety. ENSREG’s work covers the following: 

• The safety of nuclear installations in the EU;
• The safety of the management of spent fuel and radioactive waste in the EU; and
• The financing of the decommissioning of nuclear installations in the EU.