Part 21 Report - 1997-180

LICENSEE: COMMONWEALTH EDISON CO. SITE: BYRON 1 2 EN NUMBER:31890 DOCKET: 05000454 05000455 EVENT DATE: 03-03-97 RX TYPE: PWR PWR EVENT TIME: 00:00 VENDORS: W-4-LP W-4-LP NOTIFY DATE: 03-04-97 EMERGENCY CLASS: N/A REGION: 3 STATE: IL TIME: 16:22 OPS OFFICER: HENRY BAILEY 10 CFR SECTION: CCCC 21.21 UNSPECIFIED PARAGRAPH UNIT SCRAM RX INIT INITIAL MODE CURR CURRENT MODE CODE CRIT PWR PWR 1 N N 0 HOT SHUTDOWN 0 HOT SHUTDOWN 2 N Y 100 POWER OPERATION 100 POWER OPERATION 10 CFR PART 21 NOTIFICATION - CRACKING OF VITEC TRANSFORMER CORES THESE TRANSFORMERS ARE INSTALLED IN VARIOUS SAFETY-RELATED CIRCUITS BOARDS. TEMPERATURE CHANGES IN THESE CIRCUIT BOARDS COULD CAUSE ASSOCIATED INSTRUMENTATION TO DRIFT OUT OF RANGE. THE SAFETY-RELATED APPLICATIONS WHERE THIS TRANSFORMER HAS THE MOST POTENTIAL IMPACT ARE THE DELTA TEMPERATURE PROTECTION FUNCTIONS (NRA CARDS) IN THE REACTOR PROTECTION SYSTEM (RPS). THE DRIFT IN THE RPS COULD CAUSE A CHANNEL TO TRIP RESULTING IN A LOSS OF REDUNDANCY IN THE DIVERSE TRIP FUNCTION. NOTE: THIS ISSUE ALSO APPLIES TO BRAIDWOOD UNITS 1 AND 2 AND TO ZION UNITS 1 AND 2.

Page Last Reviewed/Updated Wednesday, March 24, 2021