TMI-2 instrument analysis results

The Three Mile Island, Unit 2, accident represents a unique opportunity to examine electrical equipment from an operating power plant involved in a loss-of-coolant-accident (LOCA). Over the past months several instruments have been removed from the containment building middle and upper operating levels for dissection and failure analysis. To date, two area radiation detectors, two loose parts monitoring system charge amplifiers, a source range neutron detector preamplifier and a short length of instrument cable have been examined. Interestingly, even though none of the instruments examined thus far were classified as Class 1E equipment, each was needed and used during and after the accident to monitor plant conditions, and each failed