Post-Tensioned Tendon Monitoring on the Robert E. Ginna Nuclear Containment Structure

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Micron Optics' optical sensing technology used in structural integrity test of pressurized water reactors to assess the condition of concrete containment structures.

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Micron Optics, Inc., the leading provider of innovative equipment for fiber optic sensing, today announces results of a state of the art Micron Optics structural monitoring system for post-tensioned tendons in a concrete containment structure on an operational nuclear power plant. This pilot program was integrated at the Robert E. Ginna Nuclear Power Plant in New York through collaboration between the US Department of Energy (DOE), Electric Power Research Institute (EPRI), Lucius Pitkin, Inc., and (Constellation Energy Nuclear Group) CENG.

The concrete walls of the containment structure are reinforced with 160 vertical steel tendons each post-tensioned to 650,000 pounds. Traditionally, tension has been verified with a periodic “lift-off” procedure; however, this procedure is costly, time consuming, and only provided insight during the tests.

Micron Optics fiber optic sensors were selected for the pilot due to their stable performance over long periods of time, small size, accuracy, and resistance to lightning and electromagnetic interference. Before the installation, controlled tests at Lehigh University verified that the Micron Optics sensors were capable of detecting a tension change as small as 0.1 percent. With this excellent performance and feasibility of installation verified in a lab conditions, it was time to install at the actual nuclear plant. Over 100 optical strain and temperature sensors monitor tendons, circumferential rebar, and the surface of the concrete containment dome. They are monitored continuously to determine the real-time performance of the tendons during weather extremes and over time.

A presentation titled “Overview of Fiber Optic Sensors for NDE Applications” will be presented Thursday, May 24th at the 9th International Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurized Components in Seattle, Washington. The schedule can be found at A case study associated with this project is at .

About Micron Optics, Inc.
Micron Optics’ optical sensing and imaging products make impossible measurements possible, revealing new, critical information for Infrastructure, Energy, Transportation, Medical and Industrial sectors. Since 1990, Micron Optics has been expanding its core capabilities from tunable optical components and leading-edge instrumentation and software, to complete optical sensing systems. Based in Atlanta, Georgia, USA, Micron Optics is a privately held company. For more information, visit

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Tom Graver
Micron Optics
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Andrew Peterson
Micron Optics
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