05000339/LER-2012-001, Regarding Automatic Reactor Trip Due to Turbine Trip Resulting from a Card Failure
| ML12362A011 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 12/12/2012 |
| From: | Gerald Bichof Virginia Electric & Power Co (VEPCO) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 12-681 LER 12-001-00 | |
| Download: ML12362A011 (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 |
| 3392012001R00 - NRC Website | |
text
1 0CFR50.73 Virginia Electric and Power Company North Anna Power Station P. 0. Box 402 Mineral, Virginia 23117 December 12, 2012 Attention: Document Control Desk Serial No.:
12-681 U. S. Nuclear Regulatory Commission NAPS:
MPW Washington, DC 20555-0001 Docket No.:
50-339 License No.: NPF-7
Dear Sirs:
Pursuant to 10CFR50.73, Virginia Electric and Power Company hereby submits the following Licensee Event Report applicable to North Anna Power Station Unit 2.
Report No. 50-339/2012-001-00 This report has been reviewed by the Facility Safety Review Committee and will be forwarded to the Management Safety Review Committee for its review.
Sincerely, Gerald T. Bish Site Vice President North Anna Power Station Enclosure Commitments contained in this letter: None cc:
United States Nuclear Regulatory Commission Region II Marquis One Tower 245 Peachtree Center Ave., NE, Suite 1200 Atlanta, Georgia 30303-1257 NRC Senior Resident Inspector North Anna Power Station
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 EXPIRES: 10/31/2013 (10-2010)
, the NRC may digits/characters for each block) not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. PAGE North Anna Power Station, Unit 2 05000 339 1 OF 4
- 4. TITLE Automatic Reactor Trip Due To Turbine Trip Resulting From A Card Failure
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED MONTH DAY YEAR YEAR SEQUENTIAL REV MONTH DAY YEAR FACILITY NAME DOCUMENTNUMBER I
NUMBER NO.
05000 10 24 2012 2012
-- 001 --
00 12 12 2012 FACILITY NAME DOCUMENTNUMBER 05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)
LI 20.2201(b)
[
20.2203(a)(3)(i)
LI 50.73(a)(2)(i)(C)
[]
50.73(a)(2)(vii)
LI 20.2201(d)
LI 20.2203(a)(3)(ii)
[]
50.73(a)(2)(ii)(A)
LI 50.73(a)(2)(viii)(A) 1 LI 20.2203(a)(1)
LI 20.2203(a)(4)
El 50.73(a)(2)(ii)(B) 50.73(a)(2)(viii)(B)
E] 20.2203(a)(2)(i)
[]
50.36(c)(1)(i)(A)
[F]
50.73(a)(2)(iii)
H 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL LI 20.2203(a)(2)(ii)
[]
50.36(c)(1)(ii)(A)
[] 50.73(a)(2)(iv)(A)
LI 50.73(a)(2)(x)
LI 20.2203(a)(2)(iii)
[D 50.36(c)(2)
[]
50.73(a)(2)(v)(A)
L] 73.71(a)(4)
LI 20.2203(a)(2)(iv)
LI 50.46(a)(3)(ii)
[]
50.73(a)(2)(v)(B)
[]
73.71(a)(5)
LI 20.2203(a)(2)(v)
LI 50.73(a)(2)(i)(A)
[]
50.73(a)(2)(v)(C)
[]
OTHER 100
[]
20.2203(a)(2)(vi)
[
50.73(a)(2)(i)(B)
[]
50.73(a)(2)(v)(D)
Specify in Abstract below or in
3.0 CAUSE
The direct cause of this event was a failure of the C4 capacitor (EIIS Component CAP) on the Speed Error Amplifier Card B (1A08D). When this capacitor shorted, the -15 VDC power was lost to the Operational Amplifier and this caused the Operational Amplifier to output a spurious high voltage signal to the Governor valves.
The root cause determined the evaluation of capacitor replacement frequency performed in 2002 did not use the most conservative recommendation of the card manufacturer. The evaluation did not consider the sub-component capacitor manufacturer's recommendation.
During the 2002 evaluation the card replacement recommendation from the Electro-Hydraulic Fluid Control System (EHC) Original Equipment Manufacturer (OEM) was thought to be adequate information to establish the replacement frequency of a sub-component on that card. The capacitor replacement recommendation of 10 - 20 years by the OEM was viewed as the governing standard. Benchmarking, Operating Experience (OE) and plant conditions were also used for determining replacement of the component within that band.
The replacement frequency of eight (8) refueling outages (12 years) was at the low end of the OEM specified band and was typical when compared to the industry.
4.0 IMMEDIATE CORRECTIVE ACTION(S)
The Control Room crew responded to the reactor trip in accordance with emergency procedure 2-E-0, Reactor Trip or Safety Injection. The post trip response progressed as expected and the Control Room crew transitioned to 2-ES-0.1, Reactor Trip Response. All equipment responded as designed. By 0403 hours0.00466 days <br />0.112 hours <br />6.66336e-4 weeks <br />1.533415e-4 months <br />, Unit 2 exited :2-ES-0.1 and entered 2-OP-1i.5, Unit Startup from Mode 3 to Mode 2.
5.0 ADDITIONAL CORRECTIVE ACTIONS
The EHC Speed Error Amplifier Card B (1A08D) was replaced and tested satisfactorily.
The problem with 1A08D was able to be duplicated on other Speed Error Amplifier Cards removed from the Unit 2 EHC cabinet. The speed error signal was able to be duplicated to greater than 13 VDC with the 1A08D card installed.
6.0 ACTIONS TO PREVENT RECURRENCE The preventive maintenance (PM) task basis procedure is being revised to ensure that component level replacement recommendations are obtained from component manufacturer guidance. Lessons learned from the root cause and the revision to PM will be added to the Engineering Training Program. The capacitor replacement frequency PM will be revised to align with vendor guidance. Additionally, single point vulnerabilities are being reviewed to ensure that capacitor sub-components have the appropriate replacement frequencies established.
7.0
SIMILAR EVENTS
LER 50-339-2001-005-00, dated 2/15/2005, documented an autornatic reactor trip due to a failure in the EHC power supply system. Governor valves closed causing a loss of load and subsequent low-low level in the "A" SG.
8.0 ADDITIONAL INFORMATION
Unit 1 was operating in Mode 1, 100 percent power on October 24, 2012 and was not affected by this event.
Description
Speed Error Amplifier Card Manufacturer:
Westinghouse Model No.:
IA08D
Description
Capacitor Manufacturer:
Sprague Model No.:
C4