05000528/LER-2011-002, For Palo Verde, Unit 1, Regarding Nonconforming Condition Renders the Qualified Safety Parameter Display System Inoperable
| ML11250A101 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 08/29/2011 |
| From: | Mims D Arizona Public Service Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 102-06394-DCM/JR LER 11-002-00 | |
| Download: ML11250A101 (5) | |
| 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 |
| LER closed by | |
| IR 05000528/2013002 (14 May 2013) | |
| 5282011002R00 - NRC Website | |
text
10 CFR 50.73 A: LA LA subsidiary of Pinnacle West Capital Corporation Palo Verde Nuclear Generating Station Dwight C. Mims Senior Vice President Nuclear Regulatory and Oversight Tel. 623-393-5403 Fax 623-393-6077 Mail Station 7605 P.O. Box 52034 Phoenix, Arizona 85072-2034 102-06394-DCM/JR August 29, 2011 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission 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 2011-002-00 Enclosed please find Licensee Event Report (LER) 50-528/2011-002-00 that has been prepared and submitted pursuant to 10 CFR 50.73 to report a condition prohibited by Technical Specifications. Specifically, the 120 volt class power supply cables to the A and B train Qualified Safety Parameter Display System (QSPDS) modems did not meet the minimum separation criteria, rendering both trains of QSPDS inoperable for an amount of time greater than that allowed by Technical Specifications.
In accordance with 10 CFR 50.4, copies of this LER are being forwarded to the Nuclear Regulatory Commission (NRC) Regional Office, NRC Region IV and the Senior Resident Inspector. If you have questions regarding this submittal, please contact Marianne Webb, Section Leader, Regulatory Affairs, at (623) 393-5730.
Arizona Public Service Company makes no commitments in this letter.
Sincerely, DCM/TNW/MNW/JR/gat Enclosure cc:
E. E. Collins Jr.
L. K. Gibson J. R. Hall M. A. Brown
,tC*'. c I,1AI15 NRC Region IV Regional Administrator NRC NRR Project Manager for PVNGS (electronic / paper)
NRC NRR Senior Project Manager (electronic / paper)
NRC Senior Resident Inspector for PVNGS A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway - Comanche Peak
- Diablo Canyon
- Palo Verde
- San Onofre
- South Texas
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NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2013 (10-2010)
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. PAGE Palo Verde Nuclear Generating Station (PVNGS) Unit 1 05000528 1 OF 4
- 4. TITLE Nonconforming Condition Renders the Qualified Safety Parameter Display System Inoperable
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED MONTH DAY YEAR YEAR SEQUENTIAL REV MONTH DAY YEAR FAITYNMDOKTUBE NUMBER NO.
FACILITY NAME DOCKET NUMBER 06 29 2011 2011 - 002 -
00 08 29 2011
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply)
[1 20.2201(b)
[] 20.2203(a)(3)(i)
[I 50.73(a)(2)(i)(C)
[I 50.73(a)(2)(vii)
[1 20.2201(d)
E] 20.2203(a)(3)(ii)
El 50.73(a)(2)(ii)(A)
[I 50.73(a)(2)(viii)(A)
El 20.2203(a)(1)
E] 20.2203(a)(4)
El 50.73(a)(2)(ii)(B)
[: 50.73(a)(2)(viii)(B)
[__ 20.2203(a)(2)(i)
El 50.36(c)(1)(i)(A)
[: 50.73(a)(2)(iii) 0l 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL [I 20.2203(a)(2)(ii)
El 50.36(c)(1)(ii)(A) 0l 50.73(a)(2)(iv)(A)
El 50.73(a)(2)(x)
El 20.2203(a)(2)(iii)
El 50.36(c)(2) 0l 50.73(a)(2)(v)(A)
El 73.71(a)(4)
El 20.2203(a)(2)(iv)
E] 50.46(a)(3)(ii)
[I 50.73(a)(2)(v)(B)
El 73.71(a)(5) 100 [1 20.2203(a)(2)(v)
[I 50.73(a)(2)(i)(A)
[I 50.73(a)(2)(v)(C)
El OTHER [I 20.2203(a)(2)(vi)
ED 50.73(a)(2)(i)(B)
C1 50.73(a)(2)(v)(D)
Specify in Abstract below or in
- 3.
INITIAL PLANT CONDITIONS
On June 29, 2011, Palo Verde Unit 1 was in Operating MODE 1 (Power Operation) at 100 percent power at normal operating temperature and normal operating pressure. There were no other major structures, systems, or components that were inoperable at the start of the event that contributed to the event.
4. EVENT DESCRIPTION
On June 29, 2011, in preparation for a modification to upgrade QSPDS, a walk down of the installed system in Unit 1 was performed. During the walk down, it was discovered that the 120 volt class power supply cables to the A and B train QSPDS display modems in control board B04 did not meet the minimum six inch physical separation criteria per Regulatory Guide 1.75 and Palo Verde Nuclear Generating Station (PVNGS) Installation Specification for Cable Splicing and Terminations 13-EN-0306. On July 1, 2011, at 15:30, following further evaluation by Engineering and Operations, both trains of QSPDS were declared INOPERABLE. Conditions A and C of TS LCO 3.3.10, Post Accident Monitoring (PAM)
Instrumentation, were entered. On July 3, 2011, at 16:05, both trains were declared OPERABLE and Conditions A and C of TS LCO 3.3.10 were exited after the power supply cables to the A and B train QSPDS display modems were rerouted per work order instructions to meet the physical separation criteria.
- 5.
ASSESSMENT OF SAFETY CONSEQUENCES
The inadequate separation between the power supply cables to the A and B train QSPDS display modems could potentially cause a loss of power, due to a single fault, to both of the display modems that feed the QSPDS displays located on the Unit 1 control board B04. In the event that the QSPDS displays become unavailable, the train A Post Accident Monitoring recorders on control board B02, fed directly from the A QSPDS instrument chassis, would still remain available to the operators. Additionally, the communication link between both trains of QSPDS and ERFDADS would remain available to permit full functionality of data retrieval via ERFDADS for the operators and the Emergency Response Organization.
This event did not result in any challenges to the fission product barriers or result in the release of radioactive materials. There were no actual safety consequences as a result of this event. This event did not prevent the fulfillment of a safety function and did not result in a safety system functional failure as described by 10 CFR 50.73 (a)(2)(v).
6. CAUSE OF THE EVENT
The 120 volt class power supply cables to the A and B train QSPDS display modems were installed with less than six inches of physical separation, which did not meet Regulatory Guide 1.75 Revision 1, 1975, and PVNGS Installation Specification for Cable Splicing and Terminations 13-EN-0306 separation criteria.
The event investigation is in progress and the results will be reported in a supplement to this LER.
- 7.
CORRECTIVE ACTIONS
As an immediate corrective action, the power supply cables to the A and B train QSPDS display modems were rerouted per work order instructions to meet the physical separation criteria and both trains of QSPDS were declared OPERABLE. In addition, the work order package for the QSPDS upgrade modification has been revised to contain Regulatory Guide 1.75 and PVNGS Installation Specification for Cable Splicing and Terminations 13-EN-0306 requirements in the work instructions.
The event investigation is in progress and the results will be reported in a supplement to this LER.
- 8.
PREVIOUS SIMILAR EVENTS
PVNGS has not reported a similar event in the past three years.
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