05000388/LER-2017-010-01, Condition Prohibited by Technical Specifications Due to Drift of Reactor Pressure Switches
| ML19350A281 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  (NPF-022) |
| Issue date: | 12/16/2019 |
| From: | Cimorelli K Susquehanna |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| PLA-7715 LER 2017-010-01 | |
| Download: ML19350A281 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(ix)(A) |
| 3882017010R01 - NRC Website | |
text
DEC 1 6 2019 Kevin Cimorelli 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. 570.542.3795 Fax 570.542.1504 Kevin.Cimorelli@TalenEnergy.com SUSQUEHANNA STEAM ELECTRIC STATION LICENSEE EVENT REPORT 50-388/2017-010-01 UNIT 2 LICENSE NO. NPF-22 PLA-7715 TALEN~
ENERGY 10 CFR 50.73 Docket No. 50-388 Attached is a supplement to Licensee Event Report (LER) 50-3 88/2017-010-00 that reported an event involving drifting of Reactor Pressure Steam Dome - Low pressure switches (Microswitch 2). The condition is being reported as a condition prohibited by Technical Specifications in accordance with 10 CFR 50.73(a)(2)(i)(B), a common cause in operability of independent trains or channels in accordance with 10 CFR 50.73(a)(2)(vii), a condition that could have prevented fulfillment of a safety function in accordance with 10 CFR 50.73(a)(2)(v)(D), and a single cause that could have prevented fulfillment of safety functions of trains or channels in different systems in accordance with 10 CFR 50.73(a)(2)(ix)(A).
There were no actual consequences to the health and safety of the public as a result of this event.
Attachment: LER 50-388/2017-010-01 Copy:
NRC Region I Ms. S. Goetz, NRC Project Manager Ms. L. H. Micewski, NRC Sr. Resident Inspector Mr. M. Shields, PA DEP/BRP
NRC FORM 366 (04-2018)
U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020
, 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
1 OF 3
- 4. Title Condition Prohibited by Technical Specifications Due to Drift of Reactor Pressure Switches
- 5. Event Date
- 6. LER Number
- 7. Report Date
- 8. Other Facilities Involved Sequential Rev Facility Name Docket Number Month Day Year Year Number No.
Month Day Year 05000 12 05 2017 2017
- - 010
- - 01 1'2-16 2.019 Facility Name Docket Number 05000
- 9. Operating Mode
!Abstract (Limit to 1400 spaces, i.e., approximately 14 single-spaced typewritten lines)
On December 5, 2017, the Unit 2 "C" and Unit 2 "D" Reactor Steam Dome Pressure-Low permissive pressure switches, Microswitch 2 (SW2), were found outside of the Technical Specification (TS) 3.3.5.1 allowable value. Both drifted outside of the upper allowable value which is intended to ensure that the reactor dome pressure has fallen to a value below the Core Spray and Residual Heat Removal (RHR)/Low Pressure Coolant Injection (LPCI) maximum design pressures to preclude over-pressurization of the low pressure systems prior to low pressure injection initiation.
Based on the information available, the condition existed for longer than allowed by TS 3.3.5.1 and TS 3.5.1. As such, this is a condition prohibited by TS and is being reported in accordance with 10 CFR 50. 73(a)(2)(i)(B). This is also considered a common cause inoperability of independent trains or channels (10 CFR 50.73(a)(2)(vii)), a condition that could have prevented fulfillment of a safety function (10 CFR 50.73(a)(2)(v)(D)), and a single cause that could have prevented fulfillment of safety functions of trains or channels in different systems (10 CFR 50.73(a)(2)(ix)(A)).
The direct cause was determined to be instrument setpoint drift resulting from an over-ranged condition and the effects of the movement assembly on the torque tube. Interim compensatory actions include performing calibration using the quarterly calibration procedures every 45 days on Unit 1 and every 30 days on Unit 2. Final corrective actions will include installing Cameron-Barton 288A instruments that have been modified to remove the over-range condition and the movement assembly/associated linkages that were determined to be affecting instrument drift.
There were no actual consequences to the health and safety of the public as a result of this event.
NRC FORM 366 (04-2018)
CONDITIONS PRIOR TO EVENT
Unit 1 - Mode 1, approximately 1 00 percent Rated Thermal Power Unit 2 - Mode 1, approximately 100 percent Rated Thermal Power YEAR 2017 SEQUENTIAL NUMBER
- - 010 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.
- - 01 Susquehanna Steam Electric Station (SSES) had been utilizing International Telephone and Telegraph I
(ITT)-Barton 288A pressure switches in the Reactor Steam Dome Pressure - Low channels that provide the injection permissive for the Core Spray system [EllS System Identifier: BM] (Technical Specification (TS) 3.3.5.1, Function 1 d) and the Residual Heat Removal (RHR)/Low Pressure Coolant Injection system (LPCI)
[EllS System Identifier: BO] (TS 3.3.5.1, Function 2d). Each pressure switch has two microswitches, low (SW1) and high (SW2). All eight obsolete ITT-Barton 288A pressure switches were replaced with General Electric (GE) recommended Cameron-Barton 288A pressure switches between September 6, 2017 and November 15, 2017. The Cameron Barton 288A switches were bench tested prior to installation and calibration checked at the time of installation. Subsequent calibration checks were performed at intervals more frequent than the quarterly TS required calibrations. During these subsequent calibration checks, SW2 of the Unit 2 "C" (PIS-B21-2N021 C) and Unit 2 "D" (PIS-B21-2N021 D) pressure switches [EllS System/Component Identifier: JE/PS], were found outside of the TS allowable value. A timeline of events is as follows:
September 20, 2017-the obsolete ITT-Barton 288A pressure switch for PIS-B21-2N021C was replaced with a GE recommended Cameron-Barton 288A pressure switch.
October 9, 2017-the obsolete ITT-Barton 288A pressure switch for PIS-B21-2N021 D was replaced with a GE recommended Cameron-Barton 288A pressure switch.
October 20, 2017-PIS-B21-2N021C and PIS-B21-2N021D were calibration checked and were found within the TS allowable value.
December 5, 2017-PIS-B21-2N021C and PIS-B21-2N021D were found outside of the TS allowable value during the calibration check. Both drifted outside of the upper allowable value which is intended to ensure that the reactor dome pressure has fallen to a value below the Core Spray and RHR/LPCI maximum design pressures to preclude over-pressurization of the low pressure systems prior to low pressure injection initiation. PIS-B21-2N021C exceeded the TS allowable value by 1.3 psi. PIS-B21-2N021 D exceeded the TS allowable value by 2.8 psi. Both switches were adjusted to within the TS allowable value.
After submitting LER 50-388/2017-010-00, two additional instances of drift outside of the TS allowable value were identified. Specifically, the Unit 1 "B" (PIS-B21-1 N021 B) switch was found outside the TS allowable value on June 5, 2018 and the Unit 2 "C" (PIS-B21-2N021C) switch was again found outside of the TS allowable value on June 6, 2018. The conditions were reported in LER 50-387(388)/2018-005-00, dated August 2, 2018.
NRC FORM 3668 (04-2018)
Page 2 of 3 (04-2018)
U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 LICENSEE EVENT REPORT (LER)
CONTINUATION SHEET (See NUREG-1 022, R.3 for instruction and guidance for completing this form http://www.nrc.gov/readinq-rm/doc-collections/nuregs/staff/sr1 022/r3fj
, the NRC may not conduct or
- sponsor, and a person is not required to respond to, the information collection.
Susquehanna Steam Electric Station Unit 2 05000-388 YEAR 2017
- 3. LER NUMBER SEQUENTIAL NUMBER
- - 010 Based on the information available, the condition existed for longer than allowed by TS 3.3.5.1 and TS REV NO.
- - 01 3.5.1. As such, this is a condition prohibited by TS and is being reported in accordance with 10 CFR 50.73(a)(2)(i)(B). In addition, since two Unit 2 channels were outside of the TS allowable values and impacted both Core Spray and LPCI functions, this is also considered a common cause inoperability of independent trains or channels (10 CFR 50. 73(a)(2)(vii)), a condition that could have prevented fulfillment of a safety function (10 CFR 50. 73(a)(2)(v)(D)), and a single cause that could have prevented fulfillment of safety functions of trains or channels in different systems (10 CFR 50. 73(a)(2)(ix)(A)).
CAUSE OF EVENT
The direct cause was determined to be instrument setpoint drift resulting from an over-ranged condition and I the effects of the movement assembly on the torque tube.
ANALYSIS/SAFETY SIGNIFICANCE
An engineering evaluation concluded that all components in the RHR/LPCI and Core Spray would have been able to withstand a pressure of 457.8 psig, which was the maximum recorded pressure for the instrument drift. Therefore, Core Spray and RHR/LPCI would have been able to perform their safety function. This event will not be counted as a safety system functional failure 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
Interim compensatory actions include performing calibration using the quarterly calibration procedures every 45 days on Unit 1 and every 30 days on Unit 2.
Final corrective actions will include installing Cameron-Barton 288A instruments that have been modified to remove the over-range condition and the movement assembly/associated linkages that were determined to be affecting instrument drift.
COMPONENT FAILURE INFORMATION
The switches that drifted are Cameron-Barton 288A pressure indicating switches manufactured by Cameron.
PREVIOUS SIMILAR EVENTS
LER 50-388(387)/2015-001-01, "Condition Prohibited by Technical Specifications Due to Drift of Reactor Pressure Steam Dome-Low Switches", dated February 10, 2016.
LER 50-387(388)/2018-005-00, "Condition Prohibited by Technical Specifications Due to Drift of Reactor Pressure Switches", dated August 2, 2018. Page 3 of 3