Earthquake experts and the nuclear community came together at the IAEA recently to discuss how to improve the seismic safety of nuclear installations using novel approaches.
At the IAEA workshop on 'Recent Advances in Seismic and Fault Displacement Hazard Assessment for Nuclear Installations,' hosted in Vienna, more than 120 participants from 56 countries were introduced to new approaches in seismic and fault displacement hazard assessments for nuclear installation sites.
Each year the world witnesses a number of major earthquakes, which may lead to challenges to the safety of nuclear installations. Earthquakes in some cases are followed by a tsunami, a clear example of that was the accident at the Fukushima Daiichi Nuclear Power Station in Japan in March 2011. Therefore, new methodologies in seismic and fault displacement hazard assessment have a vital role to enhance the seismic safety of nuclear installations.
"This workshop is a diverse event, with experienced professionals that share their specialised expertise with young professionals in various areas of site safety assessments that includes the fields of earthquake engineering, seismology, geology, and geophysics," said Anna Bradford, Director of the IAEA Division of Nuclear Installation Safety, in her opening remarks, adding that "open and effective communication among the participants will enhance the knowledge transfer in this field."
Participants were informed that recently, the IAEA has updated the safety guide on Seismic Hazards in Site Evaluation for Nuclear Installations with novel approaches in key technical areas such as: ground motion characterization, treatment of epistemic uncertainties, and probabilistic approaches for fault displacement hazard assessment. To support countries in the practical application of these new methodologies, a series of technical documents are being prepared by the IAEA with the support of a wide spectrum of consultants from the nuclear industry.
This workshop's sessions covered key areas of importance such as regulatory challenges in the review and assessment of seismic safety and changes in the practice in the last decade, particularly after the 2011 Fukushima Daiichi accident. Scientists shared their experience in ground motion and fault displacement modelling. Also discussed were the national practices of Japan, the US and Switzerland in the site safety assessment and changes of regulatory requirements of natural hazards, especially seismic hazards.
Professor Norman Abrahamson from the University of California, Berkeley underlined that significant changes are expected in the vibratory ground motion estimates in nuclear installation sites in the next decade with the non-ergodic approach, which allows more accurate prediction of ground motion. This workshop is an important step for introducing these changes to the nuclear community.
The IAEA supports countries with Site and External Events Design (SEED) Review missions by reviewing the site evaluations and design of nuclear installations that address challenges from earthquakes and other external events. The SEED mission provides an objective assessment of the nuclear project's conformity with IAEA safety standards and guidance such as the IAEA Safety Guide SSG-9 (Rev.1) on Seismic Hazards in Site Evaluation of Nuclear Installations.
