International Scientific Seminar on Seismic Risk and Nuclear Safety: the ASN identifies new focuses for regulatory modernisation

The international scientific seminar on seismic risk in nuclear installations, held in Strasbourg on 17 June 2009 and organised by the ASN in conjunction with the Swiss Federal Nuclear Safety Inspectorate (ENSI) and the Institute for Radiation Protection and Nuclear Safety (IRSN), allowed the ASN to identify various ways in which regulations concerning seismic risk could be modernised.

The aim of this seminar was to determine the extent to which recent scientific advances in the field of seismic risk and improved knowledge of past earthquakes can help us to reassess and reinforce the safety of nuclear installations.

More than 100 people took part, among them researchers, experts, foreign safety authorities, environmental organisations and journalists.

Experts from France, Switzerland, Germany and the United States presented the findings of the latest research on seismic risk evaluation and ways of dealing with uncertainty and site effects, as well as the engineering methods used to assess the consequences of an earthquake on nuclear installations.

Many of those in attendance raised the issue of uncertainties and how they should be taken into account in technical developments and regulatory texts. A number of experts favoured using a combination of deterministic and probabilistic approaches to estimate seismic risk, based on the most accurate data possible.

It is widely acknowledged that current aseismic structures offer a margin that allows them to withstand a level of seismic activity greater than that for which they were designed, but new methods currently being developed will make it possible to quantify these margins, providing a more reliable assessment of an installation's safety.