Application of Base-Isolation to Nuclear Facilities

Synopsis

Current practice for seismic design of structures and facilities is generally to accommodate loads or cope with displacements induced by earthquake shaking. An alternative to this approach is to filter the seismic vibration by adding flexible elements (isolators) between the structure and its base, in order to decrease the response of isolated structures and components. The isolators shift the fundamental frequency to low values and, possibly, increase the damping. This reduces inertial forces and accelerations transferred to the building.

The first seismic isolated structures were built after WWII. The first base-isolated nuclear power-plant was built in France in the 70s.

Seismic isolation has been used more and more in the last 20 years (in Japan after the 1995 Kobe earthquake, USA, France, Italy, New-Zealand) for conventional, non-nuclear structures, such as buildings, bridges, offshore oil and gas platforms, high hazard storage tanks and industrial facilities. Their design is based on developed codes and standards with controlled manufacturing and specified site construction procedures. The development is such that the technique is considered as mature, and its use has been promoted on many nuclear projects in the last 10 years. Two base-isolated research facilities (RJH and ITER) are under construction in south of France.

The lecture will describe existing isolation techniques, some examples of constructed facilities and projects. A review of existing nuclear design recommendations and codes around the world will be presented.

In addition some specifics of base isolated structures will be commented upon: impacts on construction phases, ductility demand, beyond design considerations, effect on equipment design.

About the speaker

Pierre Sollogoub is presently a consultant in seismic risk for industrial and nuclear installations. He graduated from "Ecole Nationale Supérieure de l'Aéronautique" (Paris and Toulouse) in 1970. He has 45 years’ experience in structural and dynamic analysis and design for various types of structures: from scientific instruments – telescopes – to conventional structures – steel and concrete – and nuclear structures and equipment. He has a special interest in seismic analysis and design of industrial equipment and components.

He spent 14 years with Framatome, involved in seismic design of NPP in France and abroad, and 5 years in a consulting firm specializing in seismic and geotechnical engineering. He was head of the seismic mechanics research laboratory in Saclay (CEA – Commissariat à l'Energie Atomique) between 1995 and 2008 and research director. In 2008-2010, he was in Vienna with IAEA in the International Seismic Safety Centre. Since 2010, he has been an independent consultant, during which time he has been involved in stress testing for French nuclear installations. He has also participated in standardisation activities for seismic hazard assessment and design of nuclear and industrial facilities and structures, in France, at the European level (Eurocodes) and with IAEA (seismic hazard, meteorological and hydrological events, seismic safety re-evaluation of existing facilities).

Pierre has been an active member of French Earthquake Engineering Association (AFPS – Association Française de Génie paraSismique) since 1984, participating in post-earthquake missions and in many technical working groups. He was a member and Chairman of the Scientific and Technical Committee (2004-2006) and was the President of the Association between 2012 and 2014.

Online broadcast

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Further information

This evening meeting is organised by SECED and chaired by Hamid Ahmadi (TARRC). Non-members of the society are welcome to attend. Attendance at this meeting is free. Seats are allocated on a first come, first served basis. Tea and biscuits will be served from 5.30pm - 6pm. The presentation is scheduled to finish before 7.30 pm. For further information, please contact Greg James (tel. 020 7665 2229).