05000366/LER-2005-001, Regarding Both Inboard and Outboard Main Steam Isolation Valves for the a Penetration Failed Local Leak Rate Test
| ML051020117 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 04/05/2005 |
| From: | Sumner H Southern Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NL-05-0611 LER 05-001-00 | |
| Download: ML051020117 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(ii) |
| 3662005001R00 - NRC Website | |
text
H. L Sumner, Jr.
Southern Nuclear Vice President Operating Company, Inc.
Hatch Project Post Office Box 1295 Birmingham, Alabama 35201 Tel 205.992.7279 44 SOUTHERNN..A April 5, 2005 COMPANY Energy to Serve Your World Docket No.: 50-366 NL-05-0611 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Edwin 1. Hatch Nuclear Plant - Unit 2 Licensee Event Report Inboard and Outboard Main Steam Isolation Valves Fail Local Leak Rate Test Ladies and Gentlemen:
In accordance with the requirements of 10 CFR 50.73(a)(2)(ii), Southern Nuclear Operating Company (SNC)is submitting the enclosed licensee event report (LER) concerning a failed Local Leak Rate Test on both main steam isolation valves on the 'A' main steam line.
This letter contains no NRC commitments. If you have any questions, please advise.
Sincerely, H. L. Sumner, Jr.
HLS/OCV/sdl Enclosure: LER 50-366/2005-001 cc:
Southern Nuclear Operating Company Mr. J. T. Gasser, Executive Vice President Mr. G. R. Frederick, General Manager - Plant Hatch RTYPE: CHAO2.004 U. S. Nuclear Regulatory Commission Dr. W. D. Travers, Regional Administrator Mr. C. Gratton, NRR Project Manager-Hatch Mr. D. S. Simpkins, Senior Resident Inspector-Hatch
Abstract
On 2/20/2005 at 1435 ET, Unit 2 was in the Refuel mode with fuel in the vessel and the reactor cavity flooded for refueling operations. At that time, plant engineers and technicians were performing Local Leak Rate Testing (LLRT) on Primary Containment Isolation Valves (PCIVs) when it was discovered that two Main Steam Isolation Valves (MSIVs) had failed their associated LLRT. Both valves are located in the same penetration involving the 'A' Main Steam Line. The leakage acceptance criteria for the MSIVs are contained in the plant's Technical Specifications.
The primary cause of the failure for the inboard (2B21 -F022A) MSIV appears to be degradation over a period of time. The failure of the outboard (2B21-F028A) MSIV appears to be the methodology used for testing the valve. Corrective actions for this event included repairing the valves and performing another LLRT with successful results. Finally, additional procedural guidance is being provided for the performance of Local Leak Rate Testing when using blocking pressure against the Main Steam Line plugs as a course of action to prevent recurrence.
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Based on this analysis contained in the FSAR, it is concluded that this event did not result in any adverse impact on nuclear safety. This analysis applies to all operating conditions.
CORRECTIVE ACTIONS
Valves 2B21-F022A and 2B21-F028A were disassembled and repaired. The failure of both MSIVs in one penetration to pass LLRT has not occurred within the last ten years of plant operation. Therefore, the repair of the valves and subsequent successful LLRT is considered to be a satisfactory solution.
The Local Leak Rate Testing procedure for both Unit I and Unit 2 will be revised to include the requirements for using air to provide blocking pressure between the Main Steam Line plugs and the inboard MSIVs. These procedure revisions will be completed before they are needed to be used during the next respective Unit's refueling outage.
ADDITIONAL INFORMATION
No systems other than those already mentioned in this report were affected by this event.
Failed Component Information
Master Parts List Number: 2B21-F022A&F028A Manufacturer: Rockwell International Model Number: 1612 JM MNTY Type: Valve, Shutoff Manufacturer Code: R344 EIIS System Code: SB Reportable to EPIX: Yes Root Cause Code: X EIIS Component Code: SHV
Previous Similar Events
No events have been reported in the past two years in which both the inboard and outboard Main Steam Isolation Valves for a single penetration failed LLRT.
Commitment Information: This report does not create any permanent licensing commitments.
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