05000339/LER-2013-001, Regarding Manual Reactor Trip Due to Increased Vibrations on Main Turbine/Generator Bearing Number 9

Regarding Manual Reactor Trip Due to Increased Vibrations on Main Turbine/Generator Bearing Number 9

ML13205A171
Person / Time
Site:	North Anna
Issue date:	07/02/2013
From:	Gerald Bichof Virginia Electric & Power Co (VEPCO)
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
13-309 LER 13-001-00
Download: ML13205A171 (5)

LER-2013-001, Regarding Manual Reactor Trip Due to Increased Vibrations on Main Turbine/Generator Bearing Number 9

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
3392013001R00 - NRC Website

text

1 OCFR50.73 Virginia Electric and Power Company North Anna Power Station 1022 Haley Drive Mineral, Virginia 23117 July 2, 2013 Attention: Document Control Desk Serial No.:

13-309 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. 50-339/2013-001-00 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. Bischof 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

4.

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 Manual Reactor Trip Due To Increased Vibrations on Main Turbine/Generator Bearing Number 9

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 05 10 2013 2013

-- 001 --

00 07 02 2013 FACILITY NAME DOCUMENTNUMBER 05000

9. OPERATING MODE

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

E] 20.2201(b)

Li 20.2203(a)(3)(i)

LI 50.73(a)(2)(i)(C)

Li 50.73(a)(2)(vii)

[]

20.2201(d)

LI 20.2203(a)(3)(ii) 50.73(a)(2)(ii)(A)

L] 50.73(a)(2)(viii)(A) 1 LI 20.2203(a)(1)

LI 20.2203(a)(4)

L 50.73(a)(2)(ii)(B)

[]

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

[] 20.2203(a)(2)(i)

[

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

[] 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)

[]

50.73(a)(2)(x)

[]

20.2203(a)(2)(iii)

[]

50.36(c)(2)

[]

50.73(a)(2)(v)(A)

[]

73.71(a)(4)

LI 20.2203(a)(2)(iv)

[

50.46(a)(3)(ii)

[

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

L] 73.71(a)(5)

Li 20.2203(a)(2)(v)

[

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

[]

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

[

OTHER 60

[]

20.2203(a)(2)(vi)

Li 50.73(a)(2)(i)(B)

[J 50.73(a)(2)(v)(D)

Specify in Abstract below or in

2.0 SIGNIFICANT SAFETY CONSEQUENCES AND IMPLICATIONS

No significant safety consequences resulted from this event since the Reactor Protection System (RPS) and the Engineered Safety Feature (ESF) System equipment responded as designed. As such, the event posed no significant safety implications and the health and safety of the public were not affected by the event.

On May 10, 2013, at 0820 hours0.00949 days <br />0.228 hours <br />0.00136 weeks <br />3.1201e-4 months <br />, a 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> report was made in accordance with 10CFR50.72(b)(2)(iv)(B) for RPS actuation and 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> report in accordance with 1 OCFR50.72(b)(3)(iv)(A) for the first AFW pump automatic start. This event is reportable per 10 CFR 50.73(a)(2)(iv)(A) for a condition that resulted in automatic actuation of the RPS and AFW System. The second AFW system actuation was invalid and is also being reported per 10 CFR 50.73(a)(2)(iv)(A).

3.0 CAUSE

The direct cause of the event was a combination of the alignment dowel causing a ground on the number 9 bearing pedestal which allowed electrical erosion to remove material from the bearing surface causing a hydraulic rub on the number 9 bearing and improper bearing loading caused by misalignment of the number 9 bearing pedestal.

The root cause was determined to be the Fleet Turbine Group's (FTG) lack of technical expertise coupled with a less than optimal procedure for turbine activities led to an over reliance and inadequate challenging of the turbine vendor.

The cause of the second AFW system actuation when resetting AMSAC was determined to be a procedure weakness. Procedure 2-ES-0.1 did not direct the crew to observe the proper status lights that should be expected when AMSAC has been properly reset.

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.

5.0 ADDITIONAL CORRECTIVE ACTIONS

Maintenance was performed to restore the equipment to proper functionality including replacement of the number 9 main turbine/generator bearing and the permanent magnet generator, fan and housing repairs, realignment of the exciter and number 9 pedestal, and proper installation of the number 9 pedestal alignment dowel. The hydrogen and air side seal oil temperature control was modified and the hydrogen and air side seal oil temperature indicators were calibrated.

6.0 ACTIONS TO PREVENT RECURRENCE The controlling procedure for reassembly of the turbine generator is being revised to ensure critical steps are noted and have the appropriate verifications to ensure that there is the proper level of vendor oversight, and ensure that any as left measurements that are unsatisfactory require a Condition Report to ensure there is the proper level of documentation and evaluation. Benchmarking is being performed to determine qualification/training requirements for turbine group personnel.

With regard to the second AFW pump start, procedure changes have been initiated to improve the wording contained in both 2-ES-0.1 and 2-OP-7.1 1. Lessons learned from the event will be discussed during upcoming sessions of the Licensed Operator Requalification Program (LORP).

7.0

SIMILAR EVENTS

None.

8.0 ADDITIONAL INFORMATION

Unit 1 was operating in Mode 1,100 percent power on May 10, 2013 and was not affected by this event.

Description

Shoe type bearing Manufacturer:

Siemens Part No.:

613F432G01