ML20112H007
| ML20112H007 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 06/10/1996 |
| From: | Woodard J GEORGIA POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| LCV-0797, LCV-797, NUDOCS 9606140081 | |
| Download: ML20112H007 (3) | |
Text
Georgia Power Company a
333 Piedmont Avenue 4'
' Atlanta. Georgia 30308 Telephone 404 526-3195 Mailing Address 40 Inverness Center Parkway l
Post Of6ce Box 1295 Birmingham. Alabama 3s201 i
Telephone 205 868-5086
'I J. D. Woodat d
- 8 0"*" **"" Y**
Senior Vice President LCV-0797 Docket No. 50-424 U. S. Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555 q
Gentlemen:
VOGTLE ELECTRIC GENERATING PLANT CONFIRMED LOOSE PART 14-DAY REPORT In accordance with the requirements of the Vogtle Electric Generating Plant Final Safety Analysis Report and Regulatory Guide 1.133, Georgia Power Company submits the enclosed report concerning the discovery of a loose part.
Sincerely, J
JDW/TEW/ JAB
Enclosure:
Confirmed Loose Part Report xc:
Georgia Power Comnany Mr. J. B. Beasley, Jr.
Mr. M. Sheibani NORMS U. S. Nuclear Regulatory Commission Mr. S. D. Ebneter, Regional Administrator Mr. L. L. Wheeler, Licensing Project Manager, NRR Mr C. R. Ogle, Senior Resident Inspector, Vogtle 1400'.B 9606140081 960610 1
PDR ADOCK 05000424 I
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PDR j
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i VOGTLE ELECTRIC GENERATING PLANT - UNIT 1 l
CONFIRMED LOOSE PART 14-DAY REPORT i
J A.
REQUIREMENT FOR REPORT 4
This report is required in accordance with the Vogtle Electric Generating Plant
[
Final Safety Analysis Report, Chapter 1.9, and Regulatory Guide 1.133, Section i
C6. This regulatory guide requires the submittal of a follow-up report within 14 days of the initial notification of the confirmation of a loose part. The regulatory guide requires the report to include the following information:
- 1) a summary of data obtained in the manual and automatic data acquisition modes;
- 2) a summary of the analysis, inspections, and correlations with operating data that were performed to evaluate data from the loose part detection program;
- 3) a summary of conclusions and a description of modifications or other actions planned or already performed to evaluate the safety implication of a loose part or to ensure that system and component safety functions are not impaired.
B.
DESCRIPTION OF EVENT On May 28,1996, at 0648 EDT, a digital metalimpact monitoring system (DMIMS) alarm annunciator began to continuously alarm in the control room.
Various methods were employed to confirm the existence of a loose part in steam generator (SG) # 4. After obtaining a high confidence factor that a loose part existed, the NRC Operations Center was notified at 2157 EDT, and the unit was shutdown. Information required by Regulatory Guide 1.133, Section C6, is provided as follows:
- 1) An audio check detected abnormal metallic impact sounds and the DMIMS system report registered a high number ofimpacts above the alarm setpoint for channel 760 (SG #4 primary side). A tape recording was made and sent to a vendor for analysis. In addition, a printout from a test instrument recorded hits that resembled " textbook" examples of metal impacts. The vendor analysis concluded that a loose metal object was the cause of the impacts.
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- i VOGTLE ELECTRIC GENERATING PLANT - UNIT 1 CONFIRMED LOOSE PART 14-DAY RIi. ORT P
- 2) The SG #4 hot leg manway was removed and a loose metal object was found inside. This object was a support pin nut from a control rad guide tube assembly. The nut's locking device was found usaged into the bottom of a tube and was subsequently removed. A tidrd object believed to be a fragment i
from the support pin nut, was fev.nin the SG #4 cold leg side. The support pin from which the nut cmx is believed to be intact and captured in place in 4
the reactor vessel.. A dowel pin that was attached to the nut could not be located. An ir.spection was performed of the SG #4 reactor coolant system hot
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leg with no loose parts found. The SG #4 lower tubesheet on the hot leg side warimpacted by the loose object and numerous indications were noted. The I
other 3 SG hot leg side interior surfaces were examined with no signs of 4
damage.
- 3) An engineering evaluation was performed to determine weld / pressure
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boundary integrity at the SG #4 lower tubesheet. The evaluation found no defects that would preclude safe operation of the SG under both normal and accident conditions and the unit is being returned to power operation. Repairs and/or modifications to both the tubesheet and the control rod guide tube assemblies will be considered. Any such repairs / modifications would be likely to occur at the next refueling outage and a revision to this report would be submitted following their implementation.