Protecting People and the EnvironmentUNITED STATES NUCLEAR REGULATORY COMMISSION
LICENSEE: SIEMENS POWER CORPORATION
SITE: SIEMENS POWER CORPORATION EN NUMBER:32379
DOCKET: 07001257 EVENT DATE: 05-22-97
RX TYPE: EVENT TIME: 00:00
VENDORS: NOTIFY DATE: 05-22-97
EMERGENCY CLASS: N/A REGION: 4 STATE: WA TIME: 17:13
OPS OFFICER: BOB STRANSKY
10 CFR SECTION: CDEG 21.21(c)(3)(i) DEFECTS/NONCOMPLIANCE
CRITICAL HEAT FLUX DATABASE USED FOR 9x9 FUEL DESIGNS DOES NOT
ADEQUATELY ESTIMATE UNCERTAINTIES.
THE FOLLOWING IS TEXT OF A FACSIMILE SUBMITTED BY THE VENDOR:
"DURING NRC ENGINEERING INSPECTION 9990081/97-01, THE NRC
DETERMINED THAT THE CHF [CRITICAL HEAT FLUX] DATA BASE FOR THE
ATRIUM-9 (TM) FUEL DESIGN AND OTHER 9x9 FUEL DESIGNS WITH
INTERNAL WATER CHANNELS WAS NOT EXTENSIVE ENOUGH TO ADEQUATELY
ESTIMATE THE UNCERTAINTIES FOR THE ADDITIVE CONSTANTS USED IN
SPC's (SIEMENS POWER CORPORATION) CHF CORRELATION. A STATISTICAL
TREATMENT OF THE EXISTING RELEVANT CHF DATA WAS DEVELOPED TO
ESTIMATE THE UNCERTAINTIES BEYOND THE ORIGINAL CHF DATA RANGES.
THESE ESTIMATED UNCERTAINTIES ARE LARGER THAN THE ORIGINAL
ADDITIVE CONSTANT UNCERTAINTIES. REVISED SAFETY LIMIT
CALCULATIONS WITH THE LARGER ADDITIVE CONSTANT UNCERTAINTIES
INDICATE THAT CERTAIN PLANTS MAY HAVE OPERATED WITH INCORRECT
SAFETY LIMITS.
THE AFFECTED LICENSEES HAVE BEEN INFORMED OF THE INCREASE IN
ADDITIVE CONSTANT UNCERTAINTIES AND OF THE POSSIBILITY THAT
PREVIOUSLY CALCULATED SAFETY LIMITS MAY HAVE BEEN IMPACTED BY THE
LARGER UNCERTAINTIES. SAFETY LIMIT CALCULATIONS FOR CURRENT
REACTORS WITH (THE) ATRIUM-9 FUEL DESIGN AND OTHER 9x9 FUEL
DESIGNS WITH INTERNAL WATER CHANNELS HAVE BEEN PERFORMED WITH THE
INCLUSION OF PROJECTED HIGHER ADDITIVE CONSTANT UNCERTAINTIES."
A LIST OF AFFECTED FACILITIES WAS NOT PROVIDED. THE VENDOR WILL
CONTACT NRC REGION IV REGARDING THIS ISSUE.
