05000388/LER-1917-008, Regarding Condition Prohibited by Technical Specifications Due to a Loose Terminal Block Associated with a Primary Containment Isolation Valve
| ML17261B257 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 09/18/2017 |
| From: | Berryman B Susquehanna, Talen Energy |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| PLA-7638 LER 17-008-00 | |
| Download: ML17261B257 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 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)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i) |
| 3881917008R00 - NRC Website | |
text
-! 8 2017 Brad Berryman 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 Brad.Berryman@TalenEnergy.com SUSQUEHANNA STEAM ELECTRIC STATION LICENSEE EVENT REPORT 50-388/2017-008-00 UNIT 2 LICENSE NO. NPF -22 PLA-7638 TALEN~
ENERGY 10 CFR 50.73 Docket No. 50-388 Attached is Licensee Event Report (LER) 50-388/2017-008-00. The LER reports an event involving in operability of a Primary Containment Isolation Valve (PCIV) due to a loose terminal block. This event was determined to be reportable in accordance with 10 CFR 50.73(a)(2)(i)(B) as a condition prohibited by Technical Specifications.
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.
B. Berryman Attachment: LER 50-388/2017-008-00 Copy:
NRC Region I Ms. T. E. Hood, NRC Project Manager Ms. L. H. Micewski, NRC Sr. Resident Inspector Mr. M. Shields, PA DEP/BRP
Electronic Copy:
B. Berryman N. E. Fairchild (NSRB)
J. R. Jennings D. J. LaMarca C. E. Manges T. L. Martin M. J. Murphy L. G. Oberrender S. W. Sienkiewicz R. S. Williams D. G. Kostelnik G. S. Lubinsky DCS (DBD)
(DBD)
SSES Send PDF copy to: L. Oberrender for transmittal to INPO Document Control Desk PLA-7638
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 0313112020 (04-2017) httQ://www. nrc. gov/reading-nm/doc-collections/nu regs/staff/sr1 022/r3D the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 13. PAGE Susquehanna Steam Electric Station Unit 2 05000388 1 OF3
- 4. TITLE Condition Prohibited by Technical Specifications Due to a Loose Terminal Block Associated with a Primary Containment Isolation Valve
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED SEQUENTIAL FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR REV MONTH DAY YEAR NUMBER NO.
05000 07 16 2017 2017
- - 008
- - 00 2017 FACILITY NAME DOCKET NUMBER 05000
- 9. OPERATING 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) 0 50.73(a)(2)(ii)(A)
D 50.73(a)(2)(viii)(A)
D 2o.2201(d)
D 20.2203(a)(3)(ii) 0 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)
D 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)
D 50.73(a)(2)(v)(A)
D 73.71(a)(4)
D 20.2203(a)(2)(iii)
D 50.36(c)(2)
D 50.73(a)(2)(v)(B)
D 73.71(a)(5) 100 D 20.2203(a)(2)(iv)
D 50.46(a)(3)(ii)
D 50.73(a)(2)(v)(C)
D 73.77(a)(1)
D 20.2203(a)(2)(v) 0 50.73(a)(2)(i)(A)
D 50.73(a)(2)(v)(D)
D 73.77(a)(2)(i)
D 20.2203(a)(2)(vi)
[gl50.73(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
~~LEPHONE NUMBER (Include Area Code) lc. E. Manges, Jr., Senior Engineer - Nuclear Regulatory Affairs 1(570) 542-3089
- 13. COMPLETE ONE UNE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT
CAUSE
SYSTEM COMPONENT MANU-REPORTABLE
CAUSE
SYSTEM COMPONENT MANU-REPORTABLE FACTURER TOEPIX FACTURER TO EPIX A
JM Terminal USD y
Block
- 14. SUPPLEMENTAL REPORT EXPECTED
- 15. EXPECTED MONTH DAY YEAR D YES (If yes, complete 15. EXPECTED SUBMISSION DATE)
[g) NO SUBMISSION DATE ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines)
On July 19, 2017 at approximately 02:25, while performing a control room panel walk down, Operations observed indication for Primary Containment Isolation Valves HV21313 and HV21314 extinguished. Troubleshooting commenced and Technical Specification (TS) 3.3.3.1, Condition A was entered for loss of remote position indication for HV21313 and HV21314. On July 19, 2017 at approximately 10:49, investigation of the condition concluded that the isolation circuit for HV21314 was affected and the valve would not close if called upon to do so, and TS 3.6.1.3, Condition A was entered. The investigation identified a loose terminal block.
The block was securely snapped back into the seat and the mounting screw was tightened. On July 19, 2017 at approximately 13:56, TS 3.3.3.1, Condition A and TS 3.6.1.3, Condition A were exited.
Further investigation identified that Computer Point ARZ507Z changed state from its normal Open state to the Not Open state on July 16, 2017 at 22:41 :43. The state change was indicative of reduced voltage on the circuit. It is postulated that between the computer point state change on July 16, 2017 and the light extinguishing on July 19, 2017, the light was lit but was dimmer than normal due to reduced voltage. The computer point changes state at a voltage less than the pickup voltage of the relays that control the closure of HV21314. Based on this information, the valve is considered to have been inoperable following the computer point state change.
Since the amount of time between the state change and restoration of operability was greater than allowed by Technical Specifications, this is a condition prohibited by Technical Specifications.
The cause was determined to be a loose terminal block due to a human performance error during installation in 2013. Planned corrective actions include a read and sign for applicable electricians and procedure changes regarding how to verify proper seating of terminal blocks.
There were no actual consequences to the health and safety of the public as a result of this event.
NRC FORM 366 (04-2017)
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 2017 SEQUENTIAL NUMBER
- - 008 There were no structures, systems, or components that were inoperable at the start of the event that contributed to the event.
EVENT DESCRIPTION
REV NO.
- - 00 On July 19, 2017 at approximately 02:25, while performing a control room panel walk down, Operations observed amber and red indication for Primary Containment Isolation Valves (PCIVs) HV21313 and HV21314 (Reactor Building Closed Cooling Water Outboard Isolation Valves) [EllS System/Component Identifier: CC/ISV] extinguished (should have been showing red indication with valves open). The red LED indicating lamp was changed with a known good bulb and the red indication briefly returned along with a dim amber indication while the bulb was being changed. Locally, an operator found normal indication at HV21313, but no indication for HV21314. The operator replaced the red and amber indicating lamps at the local panel with no return of indication. During the process of changing the bulb at the local panel, the red indication in the control room briefly displayed a dim indication but extinguished after approximately one minute. The operator verified Breaker 2B236092 [EllS Component Identifier: BKR] to HV21314 closed and the valve itself open. Additionally, no Bypass Indication System (BIS) alarms were indicated for a loss of power to a containment isolation indicating the issue was with indication only and not control power.
Technical Specification 3.3.3.1, Condition A was entered for loss of remote position indication for HV21313 and HV21314.
During troubleshooting, an open neutral was identified, and on July 19, 2017 at approximately 10:49, investigation of the condition concluded that the loss of continuity revealed that the isolation circuit for HV21314 was affected and the valve would not close if called upon to do so. Technical Specification 3.6.1.3, Condition A was entered. The investigation identified a loose terminal block in 2B236092 due to not being seated properly. The block was subsequently securely snapped back into the seat and the mounting screw was tightened.
On July 19, 2017 at approximately 13:56, Technical Specification 3.3.3.1, Condition A and Technical Specification 3.6.1.3, Condition A were exited.
Further investigation identified the following timeline:
On April 21, 2013, a new bucket was installed into Breaker 2B236092. The post maintenance testing (PMT) was completed on May 21, 2013.
On July 16, 2017 at 22:41:43, Computer Point ARZ507Z (RECIRC MTR RBCCW OB IN) changed state from its normal Open state to the Not Open state. The control room panel lights are monitored on a periodic basis, but Computer Point ARZ507Z is not normally monitored.
NRC FORM 3668 (04-2017)
Page 2 of 3 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 3/31/2020 (04-2017)
LICENSEE EVENT REPORT (LER)
CONTINUATION SHEET (See NUREG-1 022, R.3 for instruction and guidance for completing this form http://wwiN.nrc.gov/reading-rm/doc-collections/nureqs/staff/sr1 022/r3D
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. LER NUMBER YEAR Susquehanna Steam Electric Station Unit 2 05000-0388 2017 SEQUENTIAL NUMBER
- - 008 REV NO.
- - 00 The state change of Computer Point ARZ507Z on July 16, 2017 at 22:41:43 is indicative of reduced voltage on the circuit. It is postulated that between the computer point state change on July 16, 2017 and the light extinguishing on July 19, 2017, the light was lit but was dimmer than normal due to reduced voltage. The computer point changes state at a voltage less than the pickup voltage of the relays that control the closure of HV21314. Based on this information, the valve is considered to have been inoperable following the computer point state change. Since the amount of time between the state change and restoration of operability was greater than allowed by Technical Specifications, this is a condition prohibited by Technical Specifications and is being reported in accordance with 10 CFR 50. 73(a)(2)(i)(B). Although the event date is listed as July 16, 2017, the discovery date is considered to be July 19, 2017.
CAUSE OF EVENT
The cause was determined to be a loose terminal block caused by a human performance error during installation in 2013.
ANALYSIS/SAFETY SIGNIFICANCE
PCIV HV21314 would not have been able to electrically close with the identified condition. HV21314 is the outboard containment isolation valve. The inboard containment isolation valve, HV21346, was operable and would have provided the required isolation of the containment penetration. The containment design and testing only requires one containment isolation valve in each penetration to close for successful isolation. All containment leakage rates and all containment isolation requirements would have been met.
CORRECTIVE ACTIONS
Key corrective actions include the following:
- 1. Applicable electricians will be required to complete a read and sign regarding how to verify proper seating of terminal blocks.
- 2. A step will be added to applicable procedures regarding how to verify proper seating of terminal blocks.
COMPONENT FAILURE INFORMATION
Terminal Block, Pull Apart, 8 Pole 11330 Series manufactured by USD.
PREVIOUS SIMILAR EVENTS
No previous similar events were identified.
NRC FORM 3668 (04-2017)