05000219/LER-2002-002
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i) |
| 2192002002R00 - NRC Website | |
U.S. NUCLEAR REGULATORY COMMISSION 05000 -219 I � REV 2 � of � 3 02 � -- � 02 � -- � 00
DATE OF DISCOVERY
The condition being reported was discovered on October 11, 2002.
IDENTIFICATION OF OCCURRENCE
Main Steam Isolation Valve(MSIV) V-1-0007 (EIIC SB-ISB) exceeded the leak rate criteria specified in Technical Specification 4.5.D.2. This condition is considered to be reportable in accordance with10 CFR 50.73(a)(2)(i).
CONDITIONS PRIOR TO DISCOVERY
The plant was in a COLD SHUTDOWN condition for refueling outage 1R19 when this condition was discovered.
DESCRIPTION OF OCCURRENCE
On October 11, 2002, Local Leak Rate Testing (LLRT) results indicated that Main Steam Line Isolation Valve V-1-0007 exceeded the Technical Specification limit of .05(.75)L, at 35 psig (equivalent to 15.98 SCFH). The leak could not be quantified, but was in excess of 50 SCFH at 35 psig.
APPARENT CAUSE OF OCCURRENCE
The apparent cause of this occurrence was component degradation. This MSN had previously exceeded Technical Specification limits during the 14R refueling outage, but had successfully passed LLRT in 15R, 16R, 17R and 18R.
U.S. NUCLEAR REGULATORY COMMISSION 05000 -219 3 � of � 3 02 � -- � 02 � -- � 00
ANALYSIS OF OCCURRENCE AND SAFETY SIGNIFICANCE
The MSIVs are containment isolation valves designed to minimize the coolant loss from the vessel, and the resultant offsite dose, in the event of a main steamline break accident. The design basis loss of coolant accident was evaluated for the primary containment maximum allowable accident leak rate of 1.0% per day at an initial pressure of 35 psig, which decays to 1.0 psig after 2.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />.
The 1.0 psig is assumed to remain for the next 21.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />. The calculated leakage provides adequate margin between projected potential offsite dose and 10 CFR 100 guidelines. This projected dose was not exceeded.
The analysis for the contribution of MSIV leakage to control room habitability was reviewed. The MSIV contribution is approximately 25% (243 SCF) of the total radioactive leakage assumed (1000 SCF). The minor increase in leakage rate from the V-1-007 penetration is well bounded by the existing total radioactive leakage and, therefore, has no impact on control room habitability.
The safety significance of this event is considered minimal. The leakage past the MSIV would have been limited by the leak rate of the other MSIV in the same header which met the leak rate acceptance criteria of Technical Specification 4.5.D.2.
CORRECTIVE ACTIONS
The MSIV components were repaired and retested with satisfactory results prior to restart from the 1R19 outage.
SIMILAR EVENTS
Oyster Creek Licensing Correspondence Distribution Sheet File No. 02082 Letter Date 12/04/2002 Reference/Letter No. 2130-02-20334 Date Sent / Received 12/06/2002 Title Description: LER 2002-002; Test Results in Excess of Tech Spec Limits LICENSING ENGINEER: John Rogers SPECIAL NOTES: Distributed without attachment except as noted.
Office of the President Oyster Creek R. J. DeGregorio (Letter Only) OCAB2 E. Harkness MOB X R. Maldondo OCAB2 C Wilson MOB X Communications OCAB2 J Freeman MOB X J. Vacaro MOB Engineering S Bailey AOB V.Aggarwal OCAB3 X J..Bobba AOB M. Newcomer OCAB3 X A. Krukowski NMB A. Agarwal OCAB3 R. Ewart OCAB2 D. Barnes OCAB3 G. True Whse 2 T. E. Quintenz OCAB3 D. Norton Whse 1 M. Button OCAB3 W. Collier AOB Aux F. Buckley OCAB3 D. McMillan Bldg 12 T. Powell OCAB3 X J. Magee NMB R. Larzo OCAB3 M. Massaro OCAB2 C. Lefler OCAB3 R Adams OCAB2 X M. Moore AOB AmerGen/Exelon Other C. Pardee KSA 3-N NSRB (22 copies) G. Vanderheyden KSA 3-N B Mussel M. Gallagher (Outgoing Only) KSA 3-E X R Milos J. Hufnagel (Outgoing Only) KSA 3-E X D. Walker KSA 3-E KS Document Ctr w/ attachment KSA 1-N X I Toncic KSB 3-W D Distel KSA 3-E X Jeff Benjamin Cantera External Distribution NJBNE - K. Tosch
INPO
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