Last night ENSREG, including the European Commission, reached a consensus on the scope and modalities of a comprehensive and transparent risk and safety assessment ("stress tests") of European nuclear power plants, as requested by the European Council (24/25 March 2011). As requested by the European Council also, ENSREG made full use of available expertise, notably from the Western European Nuclear Regulators Association (WENRA), which had started working on the scope and methodology already at its spring meeting, March 22/23, 2011.
The WENRA proposal, the final version of which was submitted to ENSREG May 7, 2011, was subject to a public consultation to allow for stakeholder engagement.
On the basis of this proposal, ENSREG, including the European Commission, reached a fair degree of agreement on the scope and modalities of the “stress tests” already at their plenary meeting, May 12/13, 2011. Further consultations now have led to the consensus of last night.
This consensus comprises a Declaration and an initial independent regulatory technical definition of a “stress test” and how it should be applied to nuclear facilities across Europe (Annex I). ENSREG also proposed to establish a process in order to address risks due to security threats which are not part of ENSREG's mandate accompanied by its intention to remain associated with this process (Annex II). Both strains should contribute to a comprehensive risk and safety assessment.
ENSREG agreed that the assessment according to Annex I will cover extraordinary triggering events like earthquakes and floods and the consequences of any other initiating events (e.g. transport accidents, such as airplane crashes) potentially leading to multiple loss of safety functions requiring severe accident management.
Starting with June 1, 2011, all the operators of nuclear power plants in the EU will have to review the response of their nuclear plants to extreme situations, in particular operators will have to check and improve mitigation measures available after a potential loss of safety functions, caused by any reason. That includes the loss of electrical power or loss of ultimate heat sink for heat removal from the reactor, the management of loss of core cooling functions in their reactors as well as in spent fuel pools and the maintenance of containment integrity.
The operators’ reports will be first reviewed by the national nuclear regulators. They will then prepare summary national report, which will be reviewed by Review Teams, set up by ENSREG. A two-phase approach allows for an interim report to the European Council, December 9, 2011, and a final report to the European Council in June 2012.
As the chairman of ENSREG I am confident that ENSREG has met the high expectations of the European Council and that the scope and modalities agreed, including full transparency but also an opportunity for public involvement, will contribute to the EU "stress tests" being acknowledged by European citizens.
ENSREG, the European Nuclear Safety Regulators Group, is a high level advisory body comprising representatives of all 27 EU Member States and the European Commission.