Closeout of IE Bulletin 80-19: Failures of Mercury-Wetted Matrix Relays in Reactor Protective Systems of Operating Nuclear Power Plants Designed by Combustion Engineering
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The NRC/IE issued IE Bulletin 80-19 initially on July 31, 1980, and issued Revision 1 of the bulletin on August 13, 1980. The bulletin was issued to all licensees and holders of construction permits of power reactors, because of numerous reports about single and multiple failures of C.P. Clare Model HG2X-1011 mercury-wetted matrix relays in reactor protective systems. The concern based on those reports was that the build-up of coincident 'failed-closed' failures of certain sets of relays could result in trip failures for off-normal events. Evaluation of utility responses and NRC/Region inspection reports shows that the bulletin can be closed out per specific criteria for 100% of the 123 power facilities with operating licenses or construction permits. In effect, all of the responses and inspection reports apply to Revision 1 of the bulletin.
Closeout of IE Bulletin 80-19: Failures of Mercury-Wetted Matrix Relays in Reactor Protective Systems of Operating Nuclear Power Plants Designed by Combustion Engineering