05000387/LER-2015-008, Regarding Unit 1A Reactor Protection System Electrical Protection Assembly Breaker Underfrequency Trip Setpoint Out of Technical Specification 3.3.8.2.2 Surveillance Allowable Value for Longer than Allowed by Technical

Regarding Unit 1A Reactor Protection System Electrical Protection Assembly Breaker Underfrequency Trip Setpoint Out of Technical Specification 3.3.8.2.2 Surveillance Allowable Value for Longer than Allowed by Technical

ML15349A813
Person / Time
Site:	Susquehanna
Issue date:	12/15/2015
From:	Franke J Susquehanna, Talen Energy
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
PLA-7426 LER 15-008-00
Download: ML15349A813 (5)

LER-2015-008, Regarding Unit 1A Reactor Protection System Electrical Protection Assembly Breaker Underfrequency Trip Setpoint Out of Technical Specification 3.3.8.2.2 Surveillance Allowable Value for Longer than Allowed by Technical

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 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
3872015008R00 - NRC Website

text

DEC 1 5 2015 Jon A. Franke Site Vice President U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Susquehanna Nuclear, LLC 769 Salem Boulevard Berwick, PA 18603 Tel. 570.542.2904 Fax 570.542.1504 jon.franke@talenenergey.com SUSQUEHANNA STEAM ELECTRIC STATION LICENSEE EVENT REPORT 50-387/2015-008-00 UNIT 1 LICENSE NO. NPF-14 PLA-7426 TALEN~

ENERGY 10 CFR 50.73 Docket No. 50-387 Attached is Licensee Event Report (LER) 50-387/2015-008-00. This event was detmmined to be reportable under 10 CFR 50.73(a)(2)(i)(B) as a condition prohibited by Technical Specifications. On November 10, 2015, upon completion of an evaluation for a failed surveillance test that occmTed on September 22, 2015, a condition was identified that in 2014, a degraded Reactor Protection System Electrical Protection Assembly (EPA) breaker logic card had been installed in the Unit 1 Reactor Protection System, resulting in an unplanned inoperability of the 'A' train of the Unit 1 Reactor Protection System (RPS).

Based on the results of the evaluation, it was concluded that there was firm evidence that the condition existed prior to discovery on September 22,2015 for a period longer than allowed by Technical Specifications 3.3.8.2.2.

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.

J. A. Franke Attachment: LER 50-387/2015-008-00 Copy:

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

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 0113112017 (02-2014)

~~.,...,

, the NRC may not conduct or sponsor, and a person is not

'~no,;,~rl In '~<nnnrl In tho* infMmotinn ~1>11o~Jinn

1. FACILITY NAME

12. DOCKET NUMBER r* PAGE Susquehanna Steam Electric Station Unit 1 05000387 1 of 4

4. TITLE Unit 1 'A' Reactor Protection System Electrical Protection Assembly Breaker Underfrequency Trip Setpoint Out of Technical Specification 3.3.8.2.2 SuNeillance Allowable Value for Longer than Allowed by Technical Specifications

5. EVENT DATE

6. LER NUMBER

7. REPORT DATE

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

MONTH DAY YEAR NUMBER FACILITY NAME DOCKET NUMBER 11 10 2015 2015

- 008 00 12 15 2015 05000

9. OEPRATlNG MODE

11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §:(Check all that apply) 1 D 2o.22o1(b)

D 20.2203(a)(3)(i)

D 50.73(a)(2)(i)(C)

D 50.73(a)(2)(vii)

D 20.2201(d)

D 20.2203(a)(3)(ii)

D 50.73(a)(2)(ii)(A)

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

10. POWER LEVEL D 20.2203(a)(1)

D 20.2203(a)(4)

D 50.73(a)(2)(ii)(B) 0 50.73(a)(2)(viii)(B)

D 20.2203(a)(2)(i)

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

D 50.73(a)(2)(iii)

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

D 20.2203(a)(2)(ii)

D 50.36(c)(1 )(ii)(A)

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

D 50.73(a)(2)(x) 100 D 20.2203(a)(2)(iii)

D 50.36(c)(2)

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

D 73.71(a)(4)

D 20.2203(a)(2)(iv)

D 50.46(a)(3)(ii)

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

D 73.71 (a)(5)

D 20.2203(a)(2)(v)

D 50.73(a)(2)(i)(A) 050.73(a)(2)(v)(C) 0 OTHER D 20.2203(a)(2)(vi)

~ 50.73(a)(2)(i)(B)

D 50.73(a)(2)(v)(D)

Specify in Abstract below or in Potential consequences -

The failure of the EPA breakers to trip could potentially compromise protection to downstream RPS equipment relating to sustained over/under voltage or underfrequency conditions.

CORRECTIVE ACTIONS

Completed-The failed logic card was replaced and the Unit 1 Alternate RPS EPA breaker was declared operable.

Planned-Evaluate diagnosis and repair results for EPA breaker logic card (GE 148C6118G003 serial number 94F700-05). Ensure that either the failure is duplicated at the test facility, repaired and confirmed to no longer have the failure or the card is discarded. If there is uncertainty regarding the effectiveness of the repair, ensure the logic card is discarded.

Validate the quality of spare parts forGE 148C6118G003, Catalog number 0091062912 in the SSES warehouse. Ensure the stocked spare parts do not have a failure history or were conclusively repaired. If the quality cannot be validated, discard and re-stock with new parts.

PREVIOUS SIMILAR EVENTS

LER 2013-009-00: Reactor Protection System Electrical Protection Assembly Logic Card Under-Frequency Trip Setpoints Out of Calibration LER 2012-009-00: Multiple Test Failures of Reactor Protection System Electrical Protection Assembly Breakers INVESTIGATION (cont.)

I REVISION NUMBER

- 00

3. PAGE 30F4 testing in September 2000. Post-maintenance testing was subsequently performed on September 25, 2014 in accordance with SM 158 002, which successfully tested the underfrequency, undervoltage and overvoltage trip functions.

On December 12, 2014, due to an identified trend in underfrequency setpoints being found below the TS 3.3.8.2.2 allowable value for the RPS EPA breakers, the underfrequency setpoint tolerance was changed to accommodate vendor-specific repeatability of the setting (+/- 0.2 Hz) to ensure the circuit maintains its calibration within the TS SR 3.3.8.2.2 allowable value of_:::: 57 Hz. This also included the 1 CB-S003A-G RPS EPA breaker.

Based on the occurrence of a prior failure (on September 3, 2000) for the same logic card with the same symptoms as the failure that occurred on September 22, 2015, the SSES evaluation concluded that an inadequate parts quality existed.

REPORT ABILITY Based on the history and cause, SSES has concluded that the logic card was intermittently degraded prior to the failed surveillance on September 22, 2015. Specifically, this condition existed from the time the logic card was installed in the Unit 1 'A' train of RPS on September 25, 2014. As such, this condition existed for a period of time longer than allowed by Technical Specifications 3.3.8.2.2. As a result, this condition is being reported in accordance with 10 CFR 50.73(a)(2)(i)(B) as a condition prohibited by Technical Specifications.

CAUSE OF THE EVENT

The direct cause of the failure of the Alternate RPS 1 CB-S003A-G breaker was due to an intermittently degraded circuit (logic) card.

The apparent cause of the Alternate RPS 1 CB-S003A-G breaker failure was due to the installation of a poor quality spare electrical protection logic card in 2014. This component was sent to the OEM for analysis in 2000, but no failure was detected during that testing. As a result, SSES incorrectly concluded that the logic card did not contribute to the 2000 failure, and therefore, did not further investigate the cause or direct the logic card to be discarded to ensure a component with an intermittent failure mode was not returned to spare part status.

ANALYSIS/SAFETY SIGNIFICANCE

Actual consequences -

There were no plant conditions which warranted an underfrequency trip during the time the logic card was installed. As such, no actual consequences to the health and safety of the public.

Potential consequences -

The failure of the EPA breakers to trip could potentially compromise protection to downstream RPS equipment relating to sustained over/under voltage or underfrequency conditions.

CORRECTIVE ACTIONS

Completed-The failed logic card was replaced and the Unit 1 Alternate RPS EPA breaker was declared operable.

Planned-Evaluate diagnosis and repair results for EPA breaker logic card (GE 148C6118G003 serial number 94F700-05). Ensure that either the failure is duplicated at the test facility, repaired and confirmed to no longer have the failure or the card is discarded. If there is uncertainty regarding the effectiveness of the repair, ensure the logic card is discarded.

Validate the quality of spare parts forGE 148C6118G003, Catalog number 0091062912 in the SSES warehouse. Ensure the stocked spare parts do not have a failure history or were conclusively repaired. If the quality cannot be validated, discard and re-stock with new parts.

PREVIOUS SIMILAR EVENTS

LER 2013-009-00: Reactor Protection System Electrical Protection Assembly Logic Card Under-Frequency Trip Setpoints Out of Calibration LER 2012-009-00: Multiple Test Failures of Reactor Protection System Electrical Protection Assembly Breakers