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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