Seismic Monitoring

Seismic monitoring equipment provides a key input to safely shut down plants during a seismic event.  Accurate and reliable equipment is necessary to ensure plants are shut down in a timely manner when the seismic event is of a certain magnitude.  Conversely, the accuracy should prevent unnecessary shut downs when the event is below that magnitude.

NLI partnered with GeoSIG in 2005 to offer seismic monitoring equipment to the North American nuclear industry.  The Swiss company GeoSIG is a global leader in highly sensitive and accurate seismic monitoring equipment. GeoSIG systems are installed in nuclear plants worldwide, and in one US site.

In 2011, the nuclear industry saw two seismic events that exceeded plant design limits.  One of those events was catastrophic, but the other caused only minor damage.  The seismic event that affected the North Anna plant in Virginia raised the bar for future limits.  Knowing the exact frequency and amplitude of the event is essential to evaluating the potential effects as well as justifying the new limits.

GeoSIG also acquired products and technology from Terra Technologies.  Some nuclear plants have obsolete Terra Technologies seismic monitoring systems and components installed.