05000387/LER-2016-016, Regarding Bus Synchronizing Select Hand Switch Failure Due to Less than Adequate Life Cycle Management

Regarding Bus Synchronizing Select Hand Switch Failure Due to Less than Adequate Life Cycle Management

ML17012A334
Person / Time
Site:	Susquehanna
Issue date:	01/12/2017
From:	Franssen R Susquehanna, Talen Energy
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
PLA-7567 LER 16-016-00
Download: ML17012A334 (5)

LER-2016-016, Regarding Bus Synchronizing Select Hand Switch Failure Due to Less than Adequate Life Cycle Management

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 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)(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)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability
3872016016R00 - NRC Website

text

JAN l 2 2017 Robert J. Franssen Plant Manager U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Susquehanna Nuclear, LLC 769 Salem Boulevard Berwick, PA 18603 Tel. 570.542.3170 Fax 570.542.1504 robert.franssen@talenenergy.com SUSQUEHANNA STEAM ELECTRIC STATION LICENSEE EVENT REPORT 50-387(388)/2016-016-00 UNIT 1 LICENSE NO. NPF-14 TALEN~

ENERGY 10 CFR 50.73 UNIT 2 LICENSE NO. NPF -22 PLA-7567 Docket Nos. 50-387 50-388 Attached is Licensee Event Report (LER) 50-387(388)/2016-016-00. The LER reports an event involving failure of a bus synchronizing select hand switch. This event was determined to be reportable in accordance with 10 CFR 50.73(a)(2)(v)(A), (B), (C), and (D) as a condition that could have prevented fulfilment of a safety function.

There were no actual consequences to the health and safety of the public as a result of this event.

This letter contains no new regulatory commitments.

R. J. Franssen Attachment: LER 50-387(388)/2016-016-00 Copy:

NRC Region I Mr. J. E. Greives, NRC Sr. Resident Inspector Ms. T. E. Hood, NRC Project Manager Mr. M. Shields, PA DEP/BRP

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2018 (06-2016)

Estimated burden per response to comply with this mandala!)' collection requesl: 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />.

,.-:~\\

LICENSEE EVENT REPORT (LER)

Reported lessons learned are incorporated into the licensing process and led back to indus!!)'.

Send comments regarding burden estimate to the FOIA, Privacy and lnlonmalion Collections

~~ ~j (See Page 2 for required number of digits/characters for each block)

Branch (T-5 F53), U.S. Nuclear RegulatoJY Commission, Washington, DC 20555-0001, or by e-mail

\\........ ot to lnfocollecls.Resource@nrc.gov, and to the Desk Officer, Office of Information and RegulalaJY (See NUREG-1 022, R.3 for instruction and guidance for completing this form Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control httQ://www. nrc.gov/reading-rm/doc-collections/nur~s/staff/sr1 022/r3/)

number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

3. PAGE Susquehanna Steam Electric Station Unit 1 05000387 1 OF 4

4. TITLE Bus Synchronizing Select Hand Switch Failure Due to Less than Adequate Life Cycle Management

5. EVENT DATE

6. LER NUMBER

7. REPORT DATE

8. OTHER FACILITIES INVOLVED YEAR 1 SEQUENTIAL 1 REV FACILITY NAME DOCKET NUMBER MONTH DAY YEAR NO.

MONTH DAY YEAR Susquehanna Steam Electric Station Unit 2 05000388 NUMBER 01 1;2 FACILITY NAME DOCKET NUMBER 11 16 2016 2016 016 00 2017 05000

9. OPERATING MODE

11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: Check all that apply) 1 D 20.2201(b}

D 20.2203(a)(3)(i) 0 50.73(a)(2)(ii)(A)

D 50.73(a)(2)(viii)(A)

D 20.2201(d}

D 20.2203(a)(3)(ii)

D 50.73(a)(2)(ii)(B)

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

D 20.2203(a)(1)

D 20.2203(a)(4)

D 50.73(a)(2)(iii)

D 50.73(a)(2)(ix)(A)

D 20.2203(a)(2)(i) 0 50.36(c)(1 )(i)(A)

D 50.73(a)(2)(iv)(A)

D 50.73(a)(2)(x)

10. POWER LEVEL D 20.2203(a)(2)(ii) 0 50.36{c)(1 )(ii)(A)

[8J 50.73(a)(2)(v)(A)

D 73.71(a)(4)

D 20.2203(a)(2)(iii)

D 50.36(c)(2)

[8J 50.73(a)(2)(v)(B)

D 73.71(a)(5) 100 D 20.2203(a)(2)(iv)

D 50.46(a)(3)(ii)

[8J 50.73(a)(2)(v)(C)

D 73.77(a)(1)

D 20.2203(a)(2}(v) 0 50.73(a)(2)(i)(A)

[8J 50.73(a)(2)(v)(D)

D 73.77(a)(2)(i)

D 20.2203(a)(2)(vi) 0 50.73(a)(2)(i)(B)

D 50.73(a)(2)(vii)

D 73.77(a)(2)(ii) 0 50.73(a}(2}(i)(C) 0 OTHER Specify in Abstract below or in NRC Form 366A

12. LICENSEE CONTACT FOR THIS LER LICENSEE CONTACT

~ELEPHONE NUMBER (Include Area Code)

C. E. Manges, Jr., Senior Engineer-Nuclear Regulatory Affairs (570) 542-3089 CAUSE SYSTEM COMPONENT MANU-REPORTABLE

CAUSE

SYSTEM COMPONENT MANU-REPORTABLE FACTURER TO EPIX FACTURER TO EPIX E

EK SEL E155 Yes

14. SUPPLEMENTAL REPORT EXPECTED

15. EXPECTED MONTH DAY YEAR 0 YES (If yes, complete 15. EXPECTED SUBMISSION DATE)

~NO SUBMISSION DATE fl\\BSTRACT (Umit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines)

On November 16, 2016 at 10:45, Unit 1 and 2 entered Technical Specification (TS) 3.8.1 Conditions B, C, D, E, and G and TS 3.0.3 due to failure of a bus synchronizing select hand switch.

The failed switch prevented manual transfer between electrical sources to the Emergency Safety Switchgear (ESS) buses resulting in both offsite sources and all four diesel generators (D/Gs) being declared inoperable due to failure to meet Surveillance Requirement (SR) 3.8.1.8 and SR 3.8.1.16. This condition was reported as a condition that could have prevented fulfillment of a safety function in accordance with 10 CFR 50.72(b)(3)(v)(A), (B), (C), and (D) (EN 52369). The condition also requires this Licensee Event Report (LER) in accordance with the corresponding 10 CFR 50.73 requirements.

The direct cause was mechanical failure of an internal subcomponent of the bus synchronizing select hand switch. The apparent cause was less than adequate life cycle management. The failed switch was replaced as a corrective action. Replacement of other synchronization selector switches within the extent of condition will also be completed.

There were no actual consequences to the health and safety of the public as a result of this event.

CONDITIONS PRIOR TO EVENT

Unit 1 - Mode 1, approximately 100 percent Rated Thermal Power Unit 2 - Mode 1, approximately 100 percent Rated Thermal Power YEAR I

SEQUENTIAL I

REV NUMBER NO.

2016

- 016

- 00 There were no structures, systems, or components that were inoperable at the start of the event that contributed to the event.

EVENT DESCRIPTION

On November 16, 2016 at 10:45, Unit 1 and 2 entered TS 3.8.1 Conditions B, C, D, E, and G and TS 3.0.3 due to failure of a bus synchronizing select hand switch [EllS System I Component Identifier: EKISEL]. A detailed timeline of events is provided as follows:

November 15, 2016 at 03:51 - Units 1 and 2 entered TS 3.8.1 due to Transformer 211 [EllS System I Component Identifier: EK I XFMR] being taken out of service for scheduled maintenance (loss of one offsite source).

November 16, 2016 at 05:38-During transfer of ESS Bus 2B (2A202) [EllS System I Component Identifier:

EK I BU] to its preferred source (OX213) [EllS System I Component Identifier: EK I XFMR], both the phase and voltage spiked and then returned to normal (in phase I matched voltage) when Transformer 211 Bus 2B synchronization selector keyswitch (HS-00049B) was taken to the ON position. The transfer was completed and 2A202 was powered from its normal power supply. After the transfer, voltage was observed spiking and oscillations were observ'ed. The indication would spike and then return to normal. The handswitch was returned to the OFF position.

November 16, 2016 at 10:45-During investigation of the spiking, HS-00049B was turned to the ON position. During performance of this action, the operator reported that the switch did not feel like it went to the proper position. When the switch was taken to the OFF position, the synchroscope [EllS System I Component Identifier: EK I SYN] remained energized and the associated alarm [EllS Component Identifier:

ALM] remained locked in, which was not the expected response. Units 1 and 2 entered TS 3.8.1 Conditions B, C, D, E, and G and TS 3.0.3. The applicable off normal procedure was entered to pull fuses associated with the defective synchroscope keyswitch and restore operability to the A, C, and D DIGs and one offsite power circuit.

November 16, 2016 at 11 :30- HS-00049B was disabled in accordance with the off normal procedure by pulling fuses [EllS Component Identifier: FU] to isolate the 2B bus synchronization switches from energizing the synchronization bus. Unit 1 and 2 exited TS 3.8.1 Conditions C and E and TS 3.0.3.

November 16,2016 at 14:17-Unit 1 exited TS 3.8.1 Conditions Band D (these LCO Conditions remained in effect for Unit 2).

November 16, 2016 at 22:34-HS-00049B was replaced and the associated clearance order was removed restoring full operability of the diesel synchronization switch for the 2B bus. Page 2 of 4 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2018 (06-2016)

LICENSEE EVENT REPORT (LER)

CONTINUATION SHEET (See NUREG-1 022, R.3 for instruction and guidance for completing this form http://WNW.nrc.gov/reading-rrn/doc-collections/nureas/staff/sr1 022/r3!)

Eslimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />.

Reported lessons learned are incorporated into the licensing process and fed back to industry.

Send comments regarding burden estimate to the FOIA, Privacy and lnformalion Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to lnfocollects.Resource @nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the infonmation collection.

3. LER NUMBER Susquehanna Steam Electric Station Unit 1 05000-387 YEAR I

SEQUENTIAL I

REV NUMBER NO.

2016

- 016

- 00 The failed switch prevented manual transfer between electrical sources to the ESS buses resulting in both offsite sources and all four D/Gs being declared inoperable due to failure to meet SR 3.8.1.8 and SR 3.8.1.16. This condition was reported as a condition that could have prevented fulfillment of a safety function in accordance with 10 CFR 50.72(b)(3)(v)(A), (B), (C), and (D) (EN 52369). The condition also requires this LER in accordance with the corresponding 10 CFR 50.73 requirements.

CAUSE OF EVENT

The direct cause was mechanical failure of an internal subcomponent of HS-00049B. The plastic piece that interfaces the keyed portion of the switch to the steel shaft of the switch deck was found broken. This plastic piece most likely failed when the key was taken to the ON position while investigating the spiking.

The apparent cause was less than adequate life cycle management.

ANALYSIS/SAFETY SIGNIFICANCE

HS-00049B failed in the energized position, which prevented any other manual synchronization from being performed for 4.16kV, 13.8 kV, and the DGs as required by SR 3.8.1.8 and SR 3.8.1.16. The failure would not have prevented any automatic functions from occurring in the 4.16kV, 13.8 kV, or DG systems. The DGs were still able to start and load to the 4kV buses. The automatic transfer of the 4kV buses from primary to alternate supply was unaffected. The 13.8kV auxiliary bus fast and slow transfer logic was not impacted.

An engineering evaluation was performed and concluded that the failure of HS-000498 in the ON position would not have prevented the fulfillment of any safety functions. Details of this evaluation are as follows:

The 13.8kV system is non-Class 1 E and provides power to non-safety related plant auxiliary loads. As a result, there was no safety system functional failure associated with the 13.8kV system.

The ability of the A, B, C, D DGs (and E DG, if aligned) to start, load, and run in the event of an emergency (such as a LOCA/LOOP) was not impacted by the failure of HS-00049B. The failed switch does not impact the automatic closure of the DG output breakers. After the emergency condition is terminated (i.e., offsite power restored), the DGs are required by SR 3.8.1.16 to be able to synchronize back to offsite power.

Although this function could not be met, it is not described in the design bases as being required to fulfill any safety functions. Based on this discussion, there was no safety system functional failure associated with the Emergency Diesel Generators.

The ability of the 4kV buses to automatically transfer and to provide power to essential loads in the event of an emergency (such as a LOCA/LOOP) was not impacted by the failure of HS-00049B. The two offsite sources to each bus were not impacted: both the primary power supplies were available (Transformer 211 was available but not yet Operable following the scheduled maintenance) and the buses were able to automatically transfer to the alternate supplies. The ability to shed load (if required) was also not impacted.

Although the function of manually transferring power supplies on each 4kV bus is required by SR 3.8.1.6, it is not described in the design bases as being required to fulfill any safety functions. Based on this discussion, there was no safety system functional failure associated with 4kV. Page 3 of 4 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2018 (06-2016)

LICENSEE EVENT REPORT (LER)

CONTINUATION SHEET (See NUREG-1 022, R.3 for instruction and guidance for completing this fonm http://'N'NVV.nrc.gov/reading-nm/doc-collections/nureas/staff/sr1 022/r3/)

Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />.

Reported lessons learned are incorporated into the licensing process and fed back to industry.

Send comments regarding burden estimate to the FOIA, Privacy and Information Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to lnfocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

3. LER NUMBER Susquehanna Steam Electric Station Unit 1 05000-387 YEAR I

SEQUENTIAL I

REV NUMBER NO.

2016

- 016

- 00 Based on the engineering evaluation that concluded that the failure would not have prevented the fulfillment of any safety functions, this event will not be counted as a safety system functional failure (SSFF) for the NRC performance indicator based on the engineering analysis that shows there was no loss of ability to fulfill the safety function.

CORRECTIVE ACTIONS

Key corrective actions include the following:

1.

HS-00049B was replaced.

2.

Synchronization selector switches within the extent of condition will be replaced.

COMPONENT FAILURE INFORMATION

The failed handswitch was labeled as follows:

Manufacturer: Electroswitch Series: 20 Type: PR-20

PREVIOUS SIMILAR EVENTS

There have been two previous failures of synchronization selector switches at Susquehanna. The failures are as follows:

HS-00048B failed in the ON position May 1998 during performance of a Residual Heat Removal (RHR) Division I logic system functional test. The switch was replaced as a corrective action.

HS-00040B failed in the synchronization position in May 2013 during a monthly D/G test. This event was described in LER 50-387(388)/2013-001-01, "Diesel Generator 'B' to Bus '2B' Synchronizing Selector Switch Failure," dated November 4, 2013. A causal factor in the evaluation of the 2016 event was that corrective actions from previous failures did not implement a plan for preventing future failures. Page 4 of 4