05000369/LER-2018-001, Valid Actuation of the Unit 1 Reactor Protection System and Auxiliary Feedwater System
| ML18114A104 | |
| Person / Time | |
|---|---|
| Site: | McGuire  |
| Issue date: | 04/17/2018 |
| From: | Teresa Ray Duke Energy Carolinas |
| To: | Document Control Desk |
| References | |
| MNS-18-024 LER 2018-001-00 | |
| Download: ML18114A104 (8) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(iv)(B), System Actuation |
| 3692018001R00 - NRC Website | |
text
I e(~DUKE
~ ENERGY*
Serial No: MNS-18-024 April 17, 2018 U.S. Nuclear Regulatory Commission Washington, D.C. 20555 ATTENTION: Document Control Desk
Subject:
Duke Energy Carolinas, LLC McGuire Nuclear Station, Unit 1 Docket No. 50-369 Renewed License No. NPF-9 Licensee Event Report 369/2018-01, Revision 0 Nuclear Condition Report Number 02185409 Thomas D. Ray, P.E.
Site Vice President McGuire Nuclear Station Duke Energy MGOl VP I 12700 Hagers Ferry Road Huntersville, NC 28078 O: 980.875.4805 f: 980.875.4809 Tom.Ray@duke-energy.com 10 CFR 50.73 Pursuant to 10 CFR 50.73 Sections (a)(1) and (d), attached is Licensee Event Report (LER) 369/2018-01, Revision 0, regarding valid actuations of Unit 1 Reactor Protection System and Auxiliary Feedwater System.
This report is being submitted for Unit 1 in accordance with 10 CFR 50.73 (a) (2) (iv) (A),
"Any event or condition that resulted in manual or automatic actuation of any of the systems listed in paragraph (a) (2) (iv) (B)." The 1 O CFR 50. 73 (a) (2) (iv) (B) systems to which the requirements of paragraph (a) (2) (iv) (A) applied was the Reactor Protection System and the Auxiliary Feedwater System.
This LER is preliminary and will be supplemented upon completion of the cause analysis.. Duke Energy will provide a supplement to this LER within 30 days.
This event is considered to have no significance with respect to the health and safety of the public. There are no regulatory commitments contained in this LER.
If questions arise regarding this LER, contact Joseph F. Hussey at 980-875-5045.
ij).
Thomas D. Ray
[). ~
Site Vice President ey-McGuire Nuclear Station Attachment www.duke-energy.com
U.S. Nuclear Regulatory Commission April 17, 2018 Page 2 cc:
Catherine Haney Administrator, Region II U.S. Nuclear Regulatory Commission Marquis One Tower 245 Peachtree Center Ave.
NE Suite 1200, 30303-1257 Mike Mahoney Project Manager (McGuire)
U.S. Nuclear Regulatory Commission 11555 Rockville Pike Rockville, MD 20852-2738 Mail Stop 0-8 G9A Andy Hutto NRC Senior Resident Inspector McGuire Nuclear Station
Abstract
At 1014 [EST] hours on February 16, 2018, with Unit 1 in Mode 1 at approximately 100 percent power, the reactor was tripped when the 1 B Reactor Auxiliary Trip Breaker was actuated during Train B Solid State Protection System (SSPS) testing. The trip was uncomplicated with all systems responding normally post-trip. Operations manually started the motor driven auxiliary feedwater pumps. The turbine driven auxiliary feedwater pump auto-started on low low steam generator level in two out of four steam generators. A Feedwater Isolation occurred as designed due to the Reactor Trip and Lo Tave condition.
The preliminary cause is: Instrument and Electrical Technician took an improper action to perform hands on verification of the position of the incorrect reactor trip breaker.
This LER will be supplemented upon finalization of the cause analysis.
NRC FORM 366 (04-2017)
EVENT DESCRIPTION
YEAR 2018
- 3. LERNUMBER SEQUENTIAL NUMBER
- - 01 On February 16, 2018, while in Mode 1, an Instrument and Electrical Technician performing portions of PT/O/A/4601/008 B, "SSPS Train B Periodic Test NC Pressure Greater Than 1955 psig", actuated 1B Reactor Auxiliary Trip Breaker (BYB) tripping Unit 1.
The purpose of SSPS testing is as follows:
Verify Reactor Trip System Instrumentation surveillance requirements for automatic trip and interlock logic.
Verify Engineered Safety Features Actuation System Instrumentation surveillance requirements for automatic trip and interlock logic.
Provide Reactor Trip breaker monthly time response surveillance. This provides trendable information necessary to predict possible breaker degradation.
At 0946 Operations logged SSPS Train B inoperable to allow performance of PT/O/A/4601/008 B to begin.
Instrument and Electrical Technician 1 (Technician 1) and Instrument and Electrical Technician 2 (Technician 2) began executing procedure steps and encountered no issues until the procedure step following actuation of the Reactor Trip Breaker under test (1 RTB).. When Technician 2 approached the back of breaker CABINET-1 (RTB/BYB), he failed to perform correct component verification (CCV) and opened bypass breaker (1 BYB) compartment instead of the reactor trip (1 RTB) breaker compartment.
Upon opening the 1 BYB compartment, Technician 2 saw the 1 BYB breaker position to be closed which was not what the Technician expected. At this point Technician 2 depressed the 1 BYB TRIP button to lower the shutter to look inside. This intrusive hands on action was not directed by the procedure. Since 1 BYB was closed and the circuit energized, a reactor trip signal was generated, and Unit 1 tripped. At this point, work was suspended and management notified.
The relevant sequence of events was taken from the Control Room Logs (eSOMS) and Operator Aid Computer (OAC) alarms and is as follows (all times approximate, where time is the same the event or action is occurring within fractions of seconds):
09:46:10 SSPS TRAIN B, SSPS REACTOR TRIP BREAKER SURVEILLANCE TESTING (eSOMS) 09:46:35 1 B REACTOR AUXILIARY TRIP BREAKER (Closed) 10:14:08 U1 PZR HI PRESS RX TRIP (SSPS Test Signal) 10:14:08 U1 RX TRIP-SWGR B TRIPPED (1RTB open) 10:14:08 18 REACTOR MAIN TRIP BREAKER (1RTB open) 10:14:12 U1 PZR HI PRESS RX TRIP (SSPS Test Signal Reset) 10:14:23 18 REACTOR AUXILIARY TRIP BREAKER (1BYB Manually Opened) 10:14:23 U1 TURBINE TRIP (Reactor Trip causes Turbine Trip) 10:17:53 1A CA PUMP, (Manual Start logged) 10:17:57 18 CA PUMP (Manual Start logged) 10:19:43 1 B S/G LO-LO LEVEL RX TRIP, (OAC alarm) 10:19:45 1 D S/G LO-LO LEVEL RX TRIP, (OAC alarm) 10:20:07 TOCA PUMP, (Auto Start)
REV NO.
- - 00 REPORTABILITY DETERMINATION YEAR 2018
- 3. LERNUMBER SEQUENTIAL NUMBER
- - 01 The Unit 1 Reactor Protection System actuation while critical was a valid actuation and initially reported, as required, under 10 CFR 50. 72 (b )(2)(iv)(B), "Any event or condition that results in actuation of the Reactor Protection System (RPS) when the reactor is critical except when the actuation results from and is part of a pre-planned sequence during testing or reactor operation." The event also resulted in the valid actuation of the TOCA pump and MDCA pumps and was initially reported, as required, under 10 CFR 50.72(b)(3)(iv)(A),
and this LER will satisfy the corresponding reporting criteria 10 CFR 50. 73 (a)(2)(iv)(A), "Any event or condition that resulted in manual or automatic actuation of any of the systems listed in paragraph (a)(2)(iv)(B)." The applicable 10 CFR 50.73(a)(2)(iv)(B) systems include the Reactor Protection System and the Auxiliary Feedwater System.
CAUSAL FACTORS A cause evaluation is currently in progress. This LER will be supplemented upon finalization of the cause analysis. The preliminary cause is: The technician took an improper action to perform hands on verification of the position of the incorrect reactor trip breaker.
CORRECTIVE ACTIONS
Immediate Actions:
- 1. Technicians 1 and 2 removed from duty.
- 2. A stand down was held for supervisors to cover this event with their teams at the beginning of the next shift.
- 3. Additional qualified Maintenance technicians were called in to support recovery from 1 B Train SSPS testing.
4_
A Prompt Investigation Response Team (PIRT) was formed and investigation performed.
Subsequent Actions:
REV NO.
- - 00
- 1. Revise PT/O/A/4601/008 A and PT/O/A/4601/008 B "SSPS Train A Periodic Test NC Pressure Greater Than 1955 psig and SSPS Train B Periodic Test NC Pressure Greater Than 1955 psig" to include the following guidance:
o Place Unit Trip Potential Signage on Reactor Auxiliary Trip Breaker compartment door while breaker in service during the performance of the surveillance test. (Complete)
Establish a Critical Step per AD-HU-ALL-0004, " Procedure and Work Instruction Use and Adherence section 5.4" in both train SSPS test procedures in the step or series of steps where the Reactor Main Trip Breaker trips open. (Complete)
- 2. Coach and counsel individuals involved in the event. (Complete)
NARRATIVE Page 5 of 6 (04-2017)
U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 3/31/2020 LICENSEE EVENT REPORT (LER)
CONTINUATION SHEET (See NUREG-1022, R.3 for instruction and guidance for completing this form http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3/)
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 1. FACILITYNAME
- 2. DOCKET NUMBER McGuire Nuclear Station, Unit 1 05000-369 Planned Actions:
- 1. The LER supplement will address any necessary planned actions.
SAFETY ANALYSIS
YEAR 2018
- 3. LER NUMBER SEQUENTIAL NUMBER
- - 01 At 1014 [EST] hours on February 16, 2018, with Unit 1 in Mode 1 at approximately 100 percent power, the reactor tripped when the 1 B Reactor Auxiliary Trip Breaker was manually opened during Train B Solid State Protection System (SSPS) testing. The trip was uncomplicated with all systems responding normally post-trip. Operations manually started the motor driven auxiliary feedwater pumps. The turbine driven auxiliary feedwater pump (TDCAP) auto-started on low steam generator level. A Feedwater Isolation occurred as designed due to the Reactor Trip and Lo Tave condition. Operations stabilized the plant. Unit 2 was not affected.
The reactor tripped due to the opening of a 1 B Reactor Auxiliary Trip Breaker and the plant safety systems responded as designed. There is no safety consequence to this aspect of the event and resulted in no significant impact to the health and safety of the public.
ADDITIONAL INFORMATION
A search of the Corrective Action Program (NCR) database was conducted, based on the preliminary root cause, to determine if this event was recurring at McGuire, i.e., similar significant event with the same cause code. No NCR of similar significance with the same cause code was identified. Currently this is not considered a recurring event.
REV NO.
- - 00 Page 6 of 6