05000528/LER-2007-001, Regarding Technical Specification Prohibited Condition Due to Check Valve Not Fully Seated

Regarding Technical Specification Prohibited Condition Due to Check Valve Not Fully Seated

ML072620154
Person / Time
Site:	Palo Verde
Issue date:	09/07/2007
From:	Mims D APS, Arizona Public Service Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
102-05742-DCM/DJS LER 07-001-00
Download: ML072620154 (6)

LER-2007-001, Regarding Technical Specification Prohibited Condition Due to Check Valve Not Fully Seated

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
5282007001R00 - NRC Website

text

10 CFR 50.73 L A M*A subsidiary of Pinnacle West Capital Corporation Dwight C. Mims Mail Station 7605 Palo Verde Nuclear Vice President Tel. 623-393-5403 P. 0. Box 52034 Generating Station Regulatory Affairs and Plant Improvement Fax 623-393-6077 Phoenix, Arizona 85072-2034 102-05742-DCM/DJS September 07, 2007 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001

Dear Sirs:

Subject:

Palo Verde Nuclear Generating Station (PVNGS)

Unit I Docket No. STN 50-528 License No. NPF-41 Licensee Event Report 2007-001 -00 Attached please find Licensee Event Report (LER) 50-528/2007-001-00 that has been prepared and submitted pursuant to 10 CFR 50.73. This LER reports the failure of a containment isolation system check valve to properly seat.

Arizona Public Service Company makes no commitments in this letter.

In accordance with 10 CFR 50.73(d), copies of this LER are being forwarded to the NRC Regional Office, NRC Region IV and the Senior Resident Inspector. If you have questions regarding this submittal, please contact Ray E. Buzard, Section Leader, Regulatory Affairs, at (623) 393-5317.

Sincerely, DCM/DJS/gat Attachment cc:

B. S. Mallett NRC Region IV Regional Administrator M. T. Markley NRC NRR Project Manager - (send electronic and paper)

G. G. Warnick NRC Senior Resident Inspector for PVNGS A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway f] Comanche Peak [] Diablo Canyon 0 Palo Verde 0 South Texas Project 5 Wolf Creek 2-2~

APPROVED BY OMB: NO. 3150-0104 EXPIRES: 06/30/2007 Estimated burden per response to comply with this mandatory collection (6-2004) request: 50 hours5.787037e-4 days <br />0.0139 hours <br />8.267196e-5 weeks <br />1.9025e-5 months <br />. Reported lessons learned are incorporated into the licensing LICENSEE EVENT REPORT (LER) process and fed back to industry. Send comments regarding burden estimate to (See reverse for required number of the Records and FOIA/Privacy Service Branch (T-5 F52), U.S. Nuclear (igitsee areterse for r

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Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail to infocollects@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-1 0202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information

1. FACILITY NAME

12. DOCKET NUMBER

13. PAGE Palo Verde Nuclear Generating Station (PVNGS) Unit 1 05000528 1 OF 5

4. TITLE TECHNICAL SPECIFICATION PROHIBITED CONDITION DUE TO CHECK VALVE NOT FULLY SEATED

5. EVENT DATE

6. LER NUMBER

7. REPORT DATE

8. OTHER FACILITIES INVOLVED MONTH DAY YEAR YEAR SEQUENTIAL REV MONTH FACLITY NAME DOCKET NUMBER NUMBER NO.

05000 I.

I FACILITY NAME DOCKET NUMBER 07 05 2007 2007 - 001 -

00 09 2

2cITN 05000

9. OPERATING MODE

11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply)

[3 20.2201(b)

El 20.2203(a)(3)(i)

E_ 50.73(a)(2)(i)(C)

El 50.73(a)(2)(vii) 3 El 20.2201(d)

El 20.2203(a)(3)(ii)

C1 50.73(a)(2)(ii)(A)

[] 50.73(a)(2)(viii)(A)

El 20.2203(a)(1)

[] 20.2203(a)(4)

El 50.73(a)(2)(ii)(B)

El 50.73(a)(2)(viii)(B)

El 20.2203(a)(2)(i)

El 50.36(c)(1)(i)(A)

El 50.73(a)(2)(iii)

El 50.73(a)(2)(ix)(A)

10. POWER LEVEL E] 20.2203(a)(2)(ii)

[E 50.36(c)(1)(ii)(A)

-] 50.73(a)(2)(iv)(A)

El 50.73(a)(2)(x)

El 20.2203(a)(2)(iii)

E] 50.36(c)(2)

[E 50.73(a)(2)(v)(A)

El 73.71(a)(4)

El 20.2203(a)(2)(iv)

[I 50.46(a)(3)(ii)

El 50.73(a)(2)(v)(B)

El 73.71(a)(5) 000 El 20.2203(a)(2)(v)

El 50.73(a)(2)(i)(A)

El 50.73(a)(2)(v)(C)

El OTHER El 20.2203(a)(2)(vi) 0 50.73(a)(2)(i)(B)

El 50.73(a)(2)(v)(D)

Specify in Abstract below or in (If more space is required, use additional copies of (If more space is required, use additional copies of (If more space is required, use additional copies of (If more space is required, use additional copies of NRC Form 366A)

7.

CORRECTIVE ACTIONS

Check Valve SI-123 was disassembled and inspected. A new bonnet/disc assembly was installed in the valve and the valve passed required testing in Mode 3. Check valves S1-133 (High Pressure Safety Injection Loop Check Valve) and CHVM-70 (Regenerative Heat exchanger check valve) were also worked to optimize their performance.

Any additional corrective actions taken as a result of this event will be implemented in accordance with the PVNGS corrective action program.

8.

PREVIOUS SIMILAR EVENTS

LER 50-528/2006-005-00 reported a condition in which a Low Pressure Safety Injection (LPSI) check valve (SI-134 a Borg-Warner (B-W), 12 inch, bonnet hung, swing check valve), did not close properly. The root cause of this failure was frictional forces, in excess of the force of gravity, acting on the disc assembly which prevented the valve disc from being in its fully seated position. The areas of friction included the disc to seat landing zone, the spherical bearing outside diameter surface against the swing arm bore, and the spherical bearing against the disc/stud raised weld.

Based on the SI-1 34 event, it was determined that the corrective actions that involve optimizing the B-W swing arm check valve disc assembly and potentially refurbishing the spherical bearing should be applied to 3", 4" and 10" B-W check valves. A procedure revision was made to optimize the disc assembly configuration and refurbish/replace the spherical bearing of all 3", 4", and 10" B-W check valves that are in the IST Program during the next disassembly and inspection.

Check valve SI-123 had been initially scoped to be worked during the refueling outage (1R13) to address a Part 21 issue (2001-27-0) with weld build up and excessive gap between the swing arm and valve disc. However, a perceived shortage of replacement parts led to a reprioritization of maintenance activities. SI-1 23 had a demonstrated history of non-leakage, so it was selected to be worked at a later date. Had SI-1 23 received the refurbishing during the refueling outage, the condition could have been prevented.

Subsequent investigation revealed that the determination regarding parts unavailability was incorrect.