Preparation of specifications for the French audit and European stress tests

ASN believes that it is essential to learn from the recent accident in Japan, in the same way as after the Three Mile Island and Chernobyl accidents. The acquisition of in-depth feedback will involve a long process stretching over several years.

Between now and the end of April 2011, ASN, with the assistance of IRSN, will prepare specifications and a schedule for the audit of French nuclear facilities requested by the Prime Minister. It will also be involved in defining stress tests on European power plants, as requested by the European Commission. The Authority will ensure that these two initiatives are mutually consistent and complementary.

On 5 and 6 April 2011, ASN Deputy Director-General, Olivier Gupta, chaired a working group meeting of WENRA, the Western European Nuclear Regulators' Association. The meeting was held to prepare specifications for the European stress tests. The resulting document should be ready by the end of April.

The aim of the tests is to examine how nuclear power plants respond to extreme situations, no matter how unlikely such situations may seem. The tests will consider a number of individual and combined situations, such as natural hazards (flooding, earthquakes, severe weather), loss of power, loss of cooling water, severe accident management (fuel damage in the reactor and difficulties in cooling spent fuel pools).

Particularly close attention will be paid to the robustness and safety mechanisms in place at each facility, detecting any weak points and “threshold effects” (i.e. the stage at which severity levels increase) and suggesting possible improvements. This analysis will concern all nuclear power plants, whether in operation, under construction or planned.

All European operators will be responsible for performing stress tests in accordance with specifications and issuing a report for each of their nuclear facilities. Each national safety authority will then conduct an independent analysis of these reports and publish its conclusions. Results will also be pooled at the European level.

ASN will be devoting significant resources to this effort.