Part 21 Report - 1996-560

LICENSEE: ABB COMBUSTION ENGINEERING NUCLEAR SITE: ABB COMBUSTION ENGINEERING NUC EN NUMBER:31178 DOCKET: EVENT DATE: 10-18-96 RX TYPE: EVENT TIME: 15:15 VENDORS: NOTIFY DATE: 10-18-96 EMERGENCY CLASS: N/A REGION: 1 STATE: CT TIME: 15:10 OPS OFFICER: JOHN MacKINNON 10 CFR SECTION: CDEG 21.21(c)(3)(i) DEFECTS/NONCOMPLIANCE REPORTING OF DEFECTS AND NONCOMPLIANCE THE IDENTIFIED DEFECT INVOLVES THE APPLICATION OF CERTAIN ASPECTS OF THE ABB COMBUSTION ENGINEERING (ABB-CE) RELOAD SAFETY ANALYSIS METHODOLOGY. SPECIFICALLY, THE IDENTIFIED DEFECT CONCERNS THE SCREENING METHODOLOGY USED BY ABB-CE TO ASSESS THE CONTINUED CONSERVATISM AND APPLICABILITY OF THE DEPARTURE FROM NUCLEATE BOILING RATIO (DNBR) PROBABILITY DISTRIBUTION FUNCTION (PDF) FROM CYCLE-TO-CYCLE. THIS ASSESSMENT IN TURN PROVIDES ASSURANCE THAT THE FUEL DNBR SPECIFIC ACCEPTABLE FUEL DESIGN LIMIT (SAFDL) WILL NOT BE VIOLATED. IT IS IMPORTANT TO POINT OUT THAT THE CURRENT ABB-CE THERMAL-HYDRAULIC STATISTICAL COMBINATION OF UNCERTAINTIES (SCU) METHODOLOGY USED TO EXPLICITLY DETERMINE THE PDF INPUT TO THE DNBR SAFDL CALCULATION IS CORRECT. RATHER, THE DEFECT INVOLVES THE EVALUATION CRITERION USED DURING CYCLE SPECIFIC SCREENING TO DETERMINE WHETHER OR NOT AN EXPLICIT SCU PDF RE-ANALYSIS IS REQUIRED TO VERIFY THE CONTINUED CONSERVATISM DURING THE UPCOMING CYCLE FOR THE DNBR SAFDL OF RECORD. BASED UPON AN EVALUATION, ABB-CE HAS CONCLUDED THAT THE ABOVE DESCRIBED SITUATION REPRESENTS A DEFECT AS DEFINED IN 10 CFR 21.3, "A CONDITION OR CIRCUMSTANCE ... THAT COULD CONTRIBUTE TO THE EXCEEDING OF A SAFETY LIMIT.." THE FOLLOWING POWER PLANTS ARE POTENTIALLY AFFECTED BY THIS DEFECT: ARKANSAS NUCLEAR ONE UNIT 2; CALVERT CLIFFS UNITS 1 AND 2; PALO VERDE UNITS 1, 2, AND 3; SAN ONOFRE UNITS 2 AND 3; ST. LUCIE UNIT 2; AND WATERFORD STEAM ELECTRIC STATION UNIT 3.

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