Tuesday, September 13, 2011

Seismic Qualification Utility Group

Seismic Qualification Utility Group
In December 1980, the U.S. Nuclear Regulatory Commission (NRC) initiated Unresolved Safety Issue (USI) A-46, "Seismic Qualification of Equipment in Operating Nuclear Plants," to address the concern that there had been extensive changes in the requirements for seismic qualification of equipment over the years.  The purpose of the USI A-46 program was to verify the seismic adequacy of essential equipment in operating plants that had not been qualified in accordance with more recent criteria.
SQUG Formed
In 1982, SQUG was formed to develop a practical approach for seismic qualification of equipment in operating plants.  The approach developed by SQUG was to use experience data from the performance of equipment in power plants and industrial facilities that had been exposed to actual earthquakes as the primary basis for evaluating the seismic ruggedness and functionality of essential equipment in nuclear power plants.  Today, SQUG membership includes U.S. utilities with nuclear power plants that had been subject to USI A-46.  In addition, SQUG membership includes international utilities that have found the experience-based method to be a viable, cost-effective method for seismic qualification of equipment.  The companies that are members of SQUG are listed in the in the Contacts section of this web site. 
NRC Endorses Use of Experience Data
In 1983, the NRC issued NUREG 1018, which includes a general endorsement of the use of experience data for verification of the seismic adequacy of equipment in nuclear plants.
In early 1987, the NRC issued Generic Letter (GL) 87-02 [Reference 1] to owners of operating nuclear plants in the United States that were licensed prior to development of modern seismic qualification standards.  The recipients of GL 87-02 are referred to as A-46 plants.  Kori 2 is similar to the A-46 plants in the U.S. since its equipment was procured and installed without using IEEE Std. 344-1975 as the basis for seismic qualification of equipment.  Essentially, all owners of A-46 plants were members of SQUG.  GL 87-02 required owners to take action to verify the seismic adequacy of important equipment in their plants.  A number of International utilities with older nuclear power plant also joined SQUG to address the same type of concern that the NRC had for older U.S. nuclear power plants.

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