One of the aims of the Western European Nuclear Regulators’ Association (WENRA) that  comprises the Chief Regulators of 17 European Nuclear Regulatory Authorities is to develop a harmonized approach to reactor safety.  To achieve this objective the Reactor Harmonization Working Group (RHWG) was set up and undertook a study to develop a methodology, which was then used by WENRA to establish terms of reference for RHWG’s.

The RHWG used the following understanding of harmonization:
No substantial differences between countries from the safety point of view in generic, formally issued, national safety requirements and in their resulting implementation on nuclear power plants.

The safety areas and issues included in the study were selected to cover important aspects of reactor safety where differences in substance between WENRA countries might be expected.  They did not seek to cover everything that could have an impact upon safety or to judge the overall level of safety in existing plants.

The study indicates that the majority of the Reference Levels are implemented in nuclear power plants in WENRA countries; however, the implementation results need to be further validated.  The study also shows that there is a significant amount of work to do to align the national requirements with the Reference Levels, in view of the very strict harmonization definition.  It appears that for full harmonization, all countries have some work to do both on their regulations and on the implementation of the Reference Levels.

This work is considered to be an important input for reactor safety harmonization on existing nuclear power plants, and Slovenia is already using it to revise its regulatory requirements.  The results should be seen also as a step towards meeting WENRA’s commitment to achieving continuous improvement of reactor safety within Europe through mutual learning.

Based on WENRA Reference Levels the SNSA prepared the Action plan where harmonisation tasks to be fullfiled by 2010 were identified.