Closeout of IE Bulleting 80-19: Failures of mercury-wetted matrix relays in reactor protective systems of operating nuclear power plants designed by combustion engineering

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 failure 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. All except the three following facilities either do not have the subject relays in the reactor protective system, or have changed the relays to an acceptable type as a result of the bulletin. An inspection report closed the bulletin for Calvert Cliffs 1 and 2 based on licensee commitments to replace the mercury-wetted relays with the dry-contact type. For St. Lucie 1, the licensee elected to continue to use the subject relays and presented acceptable justification