05000530/LER-2002-001, Re Technical Specification Violation Due to Incorrect Constant Entered in Core Operating Limit Supervisory System
| ML020870483 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 03/13/2002 |
| From: | Ide W Arizona Public Service Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 192-01103-WEI/SAB/REB LER-02-001-00 | |
| Download: ML020870483 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| 5302002001R00 - NRC Website | |
text
1 OCFR50.73 William E. Ide Mail Station 7602 Palo Verde Nuclear Vice President TEL (623) 393-6116 P.O. Box 52034 Generating Station Nuclear Production FAX (623) 393-6077 Phoenix, AZ 85072-2034 192-01103-WEI/SAB/REB March 13, 2002 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 3 Docket No. STN 50-530 License No. 74 Licensee Event Report 2002-001-00 Attached please find Licensee Event Report (LER) 50-530/2002-001 -00 that has been prepared and submitted pursuant to 10CFR50.73. This LER reports a condition where Unit 3 operated with non-conservative values for the Core Operating Limit Supervisory System power operating limit margin circuit.
In accordance with 1 OCFR50.73(d), a copy of this LER is being forwarded to the NRC Regional Office, NRC Region IV and the Senior 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, WEI/SAB/REB/kg Attachment cc:
E. W. Merschoff (all with attachment)
J. H. Moorman 14, J. N. Donohew A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway
- Comanche Peak
- Diablo Canyon
- Palo Verde
- South Texas Project
- Wolf Creek
APPROVED BY OMB NO. 3150-0104 EXPIRES 7-31-2004
Abstract
On January 16, 2002 at 1316 Mountain Standard Time, with Unit 3 operating in Mode 1, Power Operations, at approximately 99 percent power, reactor engineering personnel notified control room personnel that the core operating limit supervisory system (COLSS) had constants installed that were non-conservative. This error resulted in the COLSS power-operating limit for the departure from nucleate boiling ratio (DNBR) being non-conservative.
The error was caused by engineering personnel applying an incorrect adjustment when performing a manual calculation to support cycle 10 operation following the unit's 9 th refueling outage that was completed on November 5, 2001.
Corrective action was taken to restore the COLSS constants. In addition, Units 1 and 2 were verified to have the correct constants installed.
No previous similar events have been reported in the last three years.
NRC FORM 366 (7-2001)
(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)
- 6.
CAUSE
An investigation of this condition is being conducted in accordance with the corrective action program. The direct cause of the error in the EPOL2 and EPOL4 values was an error by the responsible engineer (utility, non-licensed) for the analysis in applying an incorrect correction adjustment in the hand calculation for these parameters in the U3C10 Master Setpoint Overall Uncertainty Analysis (RA-03-C1 0-2001-020, revision 0). This hand calculation was required because when the automated computer runs were performed the engineer used an incorrect COLSS database file. An experienced engineer applied corrections by hand rather than re-running the computer program, since the calculations to be done were simple. Our human performance error prevention tools failed to prevent an error in choosing an incorrect input constant in this case. The corrective action program has captured this error, and a thorough evaluation will be completed to identify where and why the error prevention barriers failed and to identify corrective actions needed to prevent recurrence.
- 7.
CORRECTIVE ACTIONS
As a transportability action, Units 1 and 2 were verified to have the correct values installed in COLSS for the EPOL 2 and EPOL4 constants.
In addition, the calculation for Unit 3 Cycle 10 Master Setpoints Overall Uncertainty Analysis (RA-03-C1 0-2001-020) was revised to correct the values for the EPOL2 and EPOL4 constants.
Upon completion of the investigation, other corrective action(s) will be implemented.
- 8.
PREVIOUS SIMILAR EVENTS
PVNGS has not reported any similar conditions in the last three years in which an incorrect value for a constant was installed in the COLSS or the CPCs that resulted in a TS violation.
- 9.
ADDITIONAL INFORMATION
None