05000387/LER-2018-005-01, Condition Prohibited by Technical Specifications Due to Drift of Reactor Pressure Switches
| ML19350A284 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  (NPF-014, NPF-022) |
| Issue date: | 12/16/2019 |
| From: | Cimorelli K Susquehanna |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| PLA-7750 LER 2018-005-01 | |
| Download: ML19350A284 (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)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(ix)(A) |
| 3872018005R01 - 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 50-387(388)/2018-005-01 UNIT 1 LICENSE NO. NPF-14 UNIT 2 LICENSE NO. NPF -22 PLA-7750 TALEN~
ENERGY 10 CFR 50.73 Docket No. 50-387 50-388 Attached is a supplement to Licensee Event Report (LER) 50-387(388)/2018-005-00 that reported two related events involving drifting of Reactor Pressure Steam Dome-Low permissive switches (Microswitch 2). These events, one at Unit 1 and one at Unit 2, were determined to be reportable as a condition prohibited by Technical Specifications in accordance with 10 CFR 50.73(a)(2)(i)(B), a common cause inoperability 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.
This letter contains y:c~
K. Cimorelli Attachment: LER 50-387(388)/2018-005-01 Copy:
NRC Region I Ms. S. Goetz, NRC Project Manager Ms. L. H. Micewski, NRC Sr. Resident Inspector Mr. M. Shields, P A DEP/BRP
NRC FORM366 (04-2018)
U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 LICENSEE EVENT REPORT (LER)
(See Page 2 for required number of digits/characters for each block)
, 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 1 05000387 1
1 OF 4
- 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 Susquehanna Steam Electric Station Unit 2 05000388 06 05 2018 2018
- - 005
- - 01
- 12.
lb 2019 Facility Name Docket Number 05000
- 9. Operating Mode Abstract (Limit to 1400 spaces, i.e., approximately 14 single-spaced typewritten lines)
On June 5, 2018, the Unit 1 "B" Reactor Steam Dome Pressure-Low permissive pressure switch, Microswitch 2 (SW2) was found outside of the Technical Specification (TS) 3.3.5.1 allowable value during testing. Subsequently, on June 6, 2018, the Unit 2 "C" Reactor Steam Dome Pressure-Low permissive pressure switch, SW2, was found outside of the TS 3.3.5.1 allowable value during testing. Both drifted outside of the lower allowable value which is intended to ensure that the Emergency Core Cooling System (ECCS) injection prevents the fuel peak cladding temperature from exceeding the limits of 10 CFR 50.46.
Based on the information available, the condition existed for longer than allowed by Units 1 and 2, 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 100 percent Rated Thermal Power Unit 2 - Mode 1, approximately 1 00 percent Rated Thermal Power
- 3. LER NUMBER YEAR SEQUENTIAL NUMBER 2018
- - 005 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 (ITT)-Barton 288A pressure switches in the Reactor Steam Dome Pressure - Low channels [EllS System/Component Identifier: JE/PS] 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 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 to address drift issues. The Cameron-Barton 288A pressure switches were bench tested prior to installation and calibration checked at the time of installation.
Subsequent calibration checks were performed at more frequent intervals than the quarterly TS required calibrations.
After replacement, drift issues have continued. Only SW2 was found drifted outside of the TS allowable values. A detailed timeline of events is as follows:
September 20, 2017-the obsolete ITT-Barton 288A pressure switch for Unit 2 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 Unit 2 PIS-B21-2N021 D was replaced with a GE recommended Cameron-Barton 288A pressure switch.
November 15, 2017 - the obsolete ITT -Barton 288A pressure switch for Unit 1 PIS-B21-1 N021 B was replaced with a GE recommended Cameron-Barton 288A pressure switch.
I December 5, 2017-Unit 2 PIS-B21-2N021 C and Unit 2 PIS-B21-2N021 D were found outside of the TS 3.3.5.1 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. Unit 2 PIS-B21-2N021 C exceeded the TS 3.3.5.1 allowable value by 1.3 psi. Unit 2 PIS-B21-2N021 D exceeded the TS 3.3.5.1 allowable value by 2.8 psi. Both J
switches were adjusted to within the TS allowable value. These conditions were initially reported in LER 50-388/2017-010-00 on February 2, 2018.
NRC FORM 3668 (04-2018)
Page 2 of 4 (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-1022, R.3 for instruction and guidance for completing this fonm http :1/wwvv. nrc. gov/readinq-nm/doc-collections/nu regs/staff/sri 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 1 05000-387 2018 SEQUENTIAL NUMBER
- - 005 REV NO.
- - 01 June 5, 2018-Unit 1 PIS-B21-1 N021 B was found outside of the TS 3.3.5.1 allowable value during testing. The switch drifted outside of the lower allowable value which is intended to ensure that the ECCS injection prevents the fuel peak cladding temperature from exceeding the limits of 10 CFR 50.46.
PIS-B21-1N021B exceeded the TS 3.3.5.1 allowable value by 2.7 psi. The switch was adjusted to within the TS allowable value. This switch had been previously tested on December 7, 2017 and March 6, 2018 with acceptable results.
June 6, 2018-Unit 2 PIS-B21-2N021C was found outside of the TS 3.3.5.1 allowable value during testing. The switch drifted outside of the lower allowable value which is intended to ensure that the ECCS injection prevents the fuel peak cladding temperature from exceeding the limits of 10 CFR 50.46.
PIS-B21-2N021 C exceeded the TS allowable value by 1.5 psi. The switch was adjusted to within the TS allowable value. This switch had been previously tested on October 20, 2017 with acceptable results. The switch drifted outside of the upper TS 3.3.5.1 allowable value limit on December 5, 2017.
This switch was subsequently tested on January 4, 2018, February 8, 2018, March 7, 2018, and May 3, 2018 with acceptable results.
Based on the information available, the condition existed for longer than allowed by Units 1 and 2, TS 3.3.5.1 and TS 3.5.1. As such, this is a condition prohibited by Technical Specifications and is being reported in accordance with 10 CFR 50. 73(a)(2)(i)(B). In addition, SSES believes that redundant channels were inoperable at the same time impacting both Core Spray and LPCI functions; therefore, 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 the effects of the movement assembly on the torque tube.
ANALYSIS/SAFETY SIGNIFICANCE
Analysis of the condition determined a minimal impact (0.5°F) on peak cladding temperature (PCT) for a limiting break resulting in a new PCT of 1848.5°F, which is well below the 2200°F acceptance criteria.
Analysis also determined that there was no impact on the small break LOCA PCT. Based on this evaluation, 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.
NRC FORM 3668 (04-2018)
Page 3 of 4 (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/reading-rm/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 cotlection.
- 3. LER NUMBER YEAR SEQUENTIAL REV NUMBER NO.
Susquehanna Steam Electric Station Unit 1 05000-387 2018
- - 005
- - 01
CORRECTIVE ACTIONS
I Interim compensatory actions include performing calibration using the quarterly calibration procedures every I 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 50-388/2017-010-00, "Condition Prohibited by Technical Specifications Due to Drift of Reactor Pressure Switches", dated February 2, 2018.
NRC FORM 3668 (04-2018)