Activities of OECD/NEA in the fields of seismic hazard assessment & earthquake engineering

An abstract of the technical paper presented to:
20th International Conference on Structural Mechanics in Reactor Technology (SMiRT 20)
Espoo, Finland
August 9–14, 2009

Prepared by:
(a) Andrew J. Murphy, (b) Andrei Blahoianu, and (c) Alejandro Huerta
(a) U.S. Nuclear Regulatory Commission, Washington, DC, USA
(b) Canadian Nuclear Safety Commission, Ottawa, Ontario, Canada
(c) Organisation for Economic Cooperation and Development Nuclear Energy Agency, Nuclear Safety Division, Paris, France

Abstract

The Organisation for Economic Cooperation and Development (OECD)/Nuclear Energy Agency (NEA) established the seismic group to address high-level seismic safety issues from an international perspective, to provide information to member countries and to help them in assessing their nuclear facilities. The seismic group supports the Working Group on the Integrity and Ageing of Components and Structures established under the Committee on the Safety of Nuclear Installations (CSNI) dealing with safety-related research and development aspects. The seismic group makes recommendations with the objective to exchange information, to overcome discrepancies, and to reach international consensus on technical issues. The group operates through annual plenary meetings and technical workshops and by issuing state-of-the-art reports and topical opinion papers. Among other items, the recent and planned activities of the group include the following:

• updating a strategic plan for seismic group activities for the next 5 years
• conducting a meeting of specialists on seismic hazard assessment in April, 2008 in Lyon, France, with planned publication of the proceedings
• publishing a report summarizing the main findings and conclusions of a series of OECD/NEA workshops and extracting the seismic information most relevant to current nuclear practices
• discussing the worldwide implications on nuclear facilities of the July 16, 2007 Niigata-ken Chuestu-oki earthquake and its effects at the Kashiwazaki-Kariwa Nuclear power Station
• supporting a benchmark, SMART 2008, being conducted in Saclay, France, on seismic design and assessment analysis for multi-story reinforced concrete buildings subjected to torsion and nonlinear effects
• supporting the IAEA extra-budgetary program on seismic safety of existing NPP's

In April 2008, the group held a workshop on seismic hazards assessments. The objective of this workshop was to address recent findings and issues in Probabilistic Seismic Hazard Analysis (PSHA) raised during the Specialists Meeting on Seismic Probabilistic Safety Assessment of Nuclear Facilities, held in Jeju, Korea on 6-8 November 2006. (The Jeju workshop was sponsored by OECD.) The Lyon workshop addressed the issues of: a.) management of epistemic and random uncertainties, b.) the issues associated with PSHA results for areas of low-to-moderate seismicity and of the difficulties with conducting a PSHA in such an area, and c.0 comparison of PSHA results to available observations, especially for return periods where records are available. The workshop was attended by over 60 participants from 15 countries and 26 papers were presented, including five invited lectures and six panel discussions.

Annually about 25 high-level experts and specialists from 15 countries, representing safety
authorities, research organizations, electric utilities, and other international organizations (e.g., the International Atomic Energy Agency and the European Union) participate in seismic group activities.

During this annual plenary session, the group defines its programme of work and then presents it to the CSNI for approval. As conditions warrant, the CSNI provides top-down direction.

The seismic group is recognized as a forum to exchange technical information. It has no budget of its own, and activities are completed solely on in-kind contributions of its delegates.

As its first task, the seismic group developed strategic recommendations to describe its activities and identified the following topics or issues for the group to address:

• seismic analysis and design of piping
• engineering characterization of seismic input
• ageing effects, particularly as it affects seismic design
• validation of analysis methods
• re-evaluation of existing facilities and assessment of margins beyond the design basis

The seismic group has refined these topics for specific actions: to promote greater synergy between engineers and seismologists in the areas of probabilistic, performance-based and reliability-based approaches to the above strategies, development of a proposal on better understanding of soil-structure interactions and improvement of knowledge management.

This paper will detail some of the recent activities and products of the seismic group.

To obtain a copy of the abstract's document, contact the CNSC. When contacting the CNSC, please provide the title and date of the abstract.