05000364/LER-2010-002, Reactor Trip Due to Failed Feedwater Regulating Valve Controller
| ML101870487 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 07/02/2010 |
| From: | Jerrica Johnson Southern Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NL-10-1201 LER 10-002-00 | |
| Download: ML101870487 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2) 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(ix)(A) 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)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3642010002R00 - NRC Website | |
text
J.R.Johnson Vice President - Farley July 2,2010 Docket Nos.:
50-364 Southern Nuclear Operating Company, Inc.
Post Office Drawer 470 Ashford, Alabama 36312-0470 Tel 334.814.4511 Fax 334.814.4728 SOUTHERNA.
COMPANY Energy to Serve :YourWorld'"
NL-10-1201 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Joseph M. Farley Nuclear Plant - Unit 2 Licensee Event Report 2010-002-00 Reactor Trip due to Failed Feedwater Regulating Valve Controller Ladies and Gentlemen:
In accordance with the requirements of 10 CFR 50.73(a)(2)(iv)(A), Southern Nuclear Operating Company (SNC) is submitting the enclosed Licensee Event Report.
This letter contains no NRC commitments. If you have any questions, please contact Doug McKinney at (205)992-5982.
J Vice President - Farley JRJIWDO
Enclosure:
Unit 2 Licensee Event Report 2010-002-00
U. S. Nuclear Regulatory Commission NL-10-1201 Page 2 cc:
Southern Nuclear Operating Company Mr. J. T. Gasser, Executive Vice President Mr. J. R. Johnson, Vice President - Farley Ms. P. M. Marino, Vice President - Engineering RTYPE: CFA04.054 U. S. Nuclear Regulatory Commission Mr. L. A. Reyes, Regional Administrator Mr. R. E. Martin, NRR Project Manager - Farley Mr. E. L. Crowe, Senior Resident Inspector - Farley Mr. P. Boyle, NRR Project Manager
Joseph M. Farley Nuclear Plant - Unit 2 Licensee Event Report 2010-002-00 Reactor Trip due to Failed Feedwater Regulating Valve Controller Enclosure Unit 2 Licensee Event Report 2010-002-00
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 08/31/2010 9-2007)
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 13. PAGE Joseph M Farley Nuclear Plant - Unit 2 05000364 1 of 3
- 4. TITLE Reactor Trip due to Failed Feedwater Regulating Valve Controller
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED SEQUENTIAL REV FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR NUMBER NO.
MONTH DAY YEAR 05000 FACILITY NAME DOCKET NUMBER 05 22 2010 2010 - 002 -
00 07 02 2010 05000
- 9. OPERA11NG MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply) o 20.2201(b) o 20.2203(a)(3)(i) o 50.73(a)(2)(i)(C) o 50.73(a)(2)(vli) 1 o 20.2201 (d) o 20.2203(a)(3)(ii) o 5O.73(a)(2)(Ii)(A) o 50.73(a)(2)(viii)(A) o 20.2203(a)(1) o 20.2203(a)(4) o 50.73(a)(2)(ii)(B) o 5O.73(a)(2)(viii)(B) o 20.2203(a)(2)(i) o 5O.36(c)(1)(I)(A) o 50.73(a)(2)(iii) o 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL o 20.2203(a)(2)(ii) o 50.36(c)(1 )(ii)(A) 18I 50.73(a)(2)(iv)(A) o 50.73(a)(2)(x) o 20.2203(a)(2)(iii) o 50.36(c)(2) o 50.73(a)(2)(v)(A) o 73.71(a)(4) 100 o 2O.2203(a)(2)(iv) o 50.46(a)(3)(ii) o 50.73(a)(2)(v)(B) o 73.71(a)(5) o 20.2203(a)(2)(v) o 5O.73(a)(2)(i)(A) o 50.73(a)(2)(v)(C) o OTHER o 20.2203(a)(2)(vi) o 50.73(a)(2)(i)(B) o 5O.73(a)(2)(v)(D)
Specify in Abstract below or in NRC Form 366A
- 12. LICENSEE CONTACT FOR THIS LER NAME ITELEPHONE NUMBER (Indude Area Code)
J. R. Johnson - Vice President 334899-5156
- 13. COMPLETE ONE UNE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT
CAUSE
SYSTEM COMPONENT MANU-REPORTABLE
CAUSE
SYSTEM COMPONENT MANU-REPORTABLE FACTURER TO EPIX FACTURER TO EPIX B
- 14. SUPPLEMENTAL REPORT EXPECTED
- 15. EXPECTED MONTH DAY YEAR o YES (Ifyes, complete 15. EXPECTED SUBMISSION DATE) 18I NO SUBMISSION DATE
~BSTRACT(Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines)
On May 22,2010 at 16:34, with Unit 2 at 100% power, the reactor was manually tripped due to 2C Steam Generator (SG) Feedwater Regulating Valve (FRV) failing closed. At approximately 16:34, the control room crew received multiple alarms associated with 2C SG level and a process cabinet failure.
The crew noted no feedwater flow and decreasing level in 2C SG. Manual control of the 2C SG FRV was attempted but there was no power or control capability of the main feedwater regulating valve. At approximately 40% narrow range level in the 2C SG, the crew manually tripped Unit 2 prior to the automatic trip setpoint of 28% narrow range level. All safety systems functioned as designed without complications.
Investigation revealed that the controller driver (NCO) card in the 2C SG FRV controller circuitry failed causing the 2C SG FRV to close. The failed NCO card was replaced. Unit 2 was restarted and returned to Mode 1 on May 23,2010 at 17:12.
NRC FORM 366 (9-2007)
PRINTED ON RECYCLED PAPER (If more space is required, use additional copies of NRC Form 366A) (17) designed on a low-low water level signal in the 2C SG. The TDAFW pump automatically actuates on low-low level in two of three SGs and did not start since only the 2C SG experienced low-low levels.
Water level in the 2C SG recovered to normal range as expected following the manual reactor trip.
There were no safety system functional failures and all systems functioned as designed.
Corrective Action
A root cause was initiated to determine the cause of the failed NCO card. The NCO card malfunction was determined to be a S1*1 Silicon Controlled Rectifier (SCR) failure. The root cause investigation team, with support of the vendor, found only one other industry occurrence where this component failed. The failed NCO card was replaced with a new card. Unit 2 was restarted and returned to Mode 1 on May 23,2010 at 17:12.
Industry Operating Experience (OE) on the event has been issued.
Additional Information
Previous Similar Events:
LER 2008-004-00 LER 2007-001-00Unit 1 Reactor Trip due to Loss of RCP Breaker Position Unit 2 Reactor Trip during Unit 1 Main Generator Differential Lockout Relay Test PRINTED ON RECYCLED PAPER)