05000528/LER-2003-001, From Palo Verde, Unit 1 Regarding Pressurizer Safety Valve as Found Lift Pressure Outside of TS Limits

From Palo Verde, Unit 1 Regarding Pressurizer Safety Valve as Found Lift Pressure Outside of TS Limits

ML031260434
Person / Time
Site:	Palo Verde
Issue date:	04/25/2003
From:	Overbeck G Arizona Public Service Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
192-01116-GRO/SAB/DJS LER 03-001-00
Download: ML031260434 (7)

LER-2003-001, From Palo Verde, Unit 1 Regarding Pressurizer Safety Valve as Found Lift Pressure Outside of TS Limits

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
5282003001R00 - NRC Website

text

r a8LAMS 1 OCFR50.73 Gregg R. Overbeck Mail Station 7602 Palo Verde Nuclear Senior Vice President TEL (623) 393-5148 P.O Box 52034 Generating Station Nuclear FAX (623) 393-6077 Phoenix, AZ 85072-2034 192-01116-GRO/SAB/DJS April 25,2003 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Station P1-37 Washington, DC 20555-0001

Dear Sirs:

Subject:

Palo Verde Nuclear Generating Station (PVNGS)

Unit 1 Docket No. STN 50-528 License No. NPF-41 Licensee Event Report 2003-001-00 Attached please find Licensee Event Report (LER) 50-528/2003-001-00 that has been prepared and submitted pursuant to 10CFR50.73(a)(2)(i)(B). This LER reports the findings and corrective actions taken in response to a single, out of tolerance (OOT) pressurizer safety valve (PSV) which was discovered during post-outage testing The as-found lift pressure for one Unit 1 PSV was outside of the tolerance allowed by Technical Specification Limiting Condition for Operation 3.4.10. The PSVs removed from Unit 1 were as-found lift tested, disassembled, inspected, reassembled and certified at NWS Technologies laboratories.

The actions taken as a result of the out of tolerance PSV are being performed in accordance with the PVNGS corrective action program. The corrective actions described in this LER are not necessary to maintain compliance with regulations. As such, APS may modify these corrective actions as necessary to improve PSV reliability and performance.

In accordance with 10CFR50.73 (d), a copy of this LER is being forwarded to the NRC Regional Office, NRC Region IV and the Resident Inspector. If you have questions regarding this submittal, please contact Daniel G. Marks, Section Leader, Regulatory Affairs, at (623) 393-6492.

Arizona Public Service Company makes no commitments in this letter.

Sincerely, G RO/SAB/DJS/kg Attachment cc:

E. W. Merschoff N. L. Salgado J. N. Donohew (all with attachment)

APPROVED BY OMB NO. 3150-0104 EXPIRES 7-31-2004

Abstract

On March 5, 2003, lift pressure verification testing was completed on pressurizer safety valves (PSVs) that had been removed during the Unit 1 tenth refueling outage. The testing revealed that the as-found lift pressure for one Unit 1 PSV was outside the Technical Specification limits of +3, -1 percent of design lift pressure.

The out of tolerance as-found PSV condition appears to be the result of a spring whose physical condition relaxed over time and would no longer meet vendor specifications. The impact of the Unit 1 PSV Out of Tolerance (OOT) was evaluated and it was determined the results based on the as-found conditions were bounded by the peak Reactor Coolant System (RCS) pressure results of the current Loss of Condenser Vacuum (LOCV) analysis of record (AOR) (A-PV2-FE-01 60, Rev 2). LOCV is the most limiting event for peak primary pressure that is impacted by the PSV high OOT condition.

Previous similar events have been reported in the last three years.

NRC tFUHI 366 tf-)

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PREVIOUS SIMILAR EVENTS

Similar out-of-tolerance PSV conditions were reported in previously submitted LERs 529/1999-004 and 529/2000-008, where setpoint drift was the cause of the out-of-tolerance conditions. In this instance, the out-of-tolerance condition appears to be the result of spring relaxation. Although previous corrective actions have been effective in reducing the number of out-of-tolerance PSVs, as-found out-of-tolerance conditions periodically occur. APS evaluates industry operating experience for corrective actions that may improve PSV performance and APS may implement additional actions if they are demonstrated to be effective.