IR 05000269/2019013
| ML19318G943 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 11/14/2019 |
| From: | Steven Rose NRC/RGN-II |
| To: | Burchfield J Duke Energy Carolinas |
| Archer L | |
| References | |
| IR 2019013 | |
| Download: ML19318G943 (11) | |
Text
November 14, 2019
SUBJECT:
OCONEE NUCLEAR STATION - NRC TEMPORARY INSTRUCTION 2515/194 OPEN PHASE CONDITION INSPECTION REPORT 05000269/2019013 AND 05000270/2019013 AND 05000287/2019013
Dear Mr. Burchfield,
Jr.:
On October 10, 2019, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Oconee Nuclear Station Units 1, 2, and 3 and discussed the results of this inspection with Mr.
Paul Fisk and other members of your staff. The results of this inspection are documented in the enclosed report.
The NRC inspectors did not identify any finding or violation of more than minor significance.
This letter, its enclosure, and your response (if any) will be made available for public inspection and copying at http://www.nrc.gov/reading-rm/adams.html and at the NRC Public Document Room in accordance with 10 CFR 2.390, Public Inspections, Exemptions, Requests for Withholding.
Sincerely,
/RA/
Steven D. Rose, Chief Construction Inspection Branch 2 Division of Construction Oversight
Docket Nos. 05000269 and 05000270 and 05000287 License Nos. DPR-38 and DPR-47 and DPR-55
Enclosure:
As stated
Inspection Report
Docket Numbers:
05000269, 05000270 and 05000287
License Numbers:
Report Numbers:
05000269/2019013, 05000270/2019013 and 05000287/2019013
Enterprise Identifier: I-2019-013-0008
Licensee:
Duke Energy Carolinas, LLC
Facility:
Oconee Nuclear Station
Location:
Seneca, SC
Inspection Dates:
October 07, 2019 to October 10, 2019
Inspectors:
G. Crespo, Sr. Construction Inspector
Approved By:
Steven D. Rose, Chief
Construction Inspection Branch 2
Division of Construction Oversight
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an NRC Temporary Instruction 2515/194 Open Phase Condition Inspection at Oconee Nuclear Station in accordance with the Reactor Oversight Process. The Reactor Oversight Process is the NRCs program for overseeing the safe operation of commercial nuclear power reactors. Refer to https://www.nrc.gov/reactors/operating/oversight.html for more information.
List of Findings and Violations
No findings or violations of more than minor significance were identified.
Additional Tracking Items
None.
INSPECTION SCOPES
Inspections were conducted using the appropriate portions of the inspection procedures (IPs) in effect at the beginning of the inspection unless otherwise noted. Currently approved IPs with their attached revision histories are located on the public website at http://www.nrc.gov/reading-rm/doc-collections/insp-manual/inspection-procedure/index.html. Samples were declared complete when the IP requirements most appropriate to the inspection activity were met consistent with Inspection Manual Chapter (IMC) 2515, Light-Water Reactor Inspection Program - Operations Phase. The inspectors reviewed selected procedures and records, observed activities, and interviewed personnel to assess licensee performance and compliance with Commission rules and regulations, license conditions, site procedures, and standards.
OTHER ACTIVITIES
- TEMPORARY INSTRUCTIONS, INFREQUENT AND ABNORMAL
2515/194 - Inspection of the Licensees Implementation of Industry Initiative Associated With the Open Phase Condition Design Vulnerabilities In Electric Power Systems (NRC Bulletin 2012-01)
This inspection was conducted using Temporary Instruction 2515/194 (ADAMS Accession No.
ML17137A416), dated October 31, 2017. The inspectors reviewed the licensees implementation of Nuclear Energy Institute (NEI) voluntary industry initiative (VII) in compliance with Commission guidance. The inspector discussed the licensees open phase condition system design and ongoing implementation plans with plant staff. The inspectors reviewed licensee documentation, vendor documentation, and performed system walkdowns to verify that the installed equipment was supported by the design documentation. These reviews were also made to determine if the licensee had completed the installation and testing of equipment, installed and tested alarming circuits both local and in the control room, and analyzed potential impacts associated with the design implementation on the current licensing basis. The inspectors reviewed the status of indication lamps in the front of the individual system cabinets to verify the status of the system tripping functions. These tripping functions of the system had not been activated or wired to date pending resolution of decision if to activate the function.
The objective of TI 2515/194 was to verify that licensees had appropriately implemented the NEI VII (ADAMS Accession No. ML15075A454), dated March 16, 2015, including updating their licensing basis to reflect the need to protect against OPCs.
Inspection of the Licensees Implementation of Industry Initiative Associated With the Open Phase Condition Design Vulnerabilities In Electric Power Systems (NRC Bulletin 2012-01) (1 Sample)
- (1) Temporary Instruction 2515/194-03.01 - VII (Part 1)
Oconee Nuclear Station, Units 1, 2, and 3 selected the open phase detection system designed and manufactured by Power System Sentinel Technologies, LLC. At the end of this inspection, the system remained in the monitoring mode of operation to facilitate continued data gathering of grid perturbations for evaluation of alarm and trip setpoints. The equipment was installed on start-up transformers CT-1, CT-2, CT-3, CT-5 and the Keowee Main Step Up (KMSU). The licensee is scheduled to transition the open phase detection system to full implementation including trip functions, if so decided, by December
INSPECTION RESULTS
Assessment 2515/194 Detection, Alarms, and General Criteria: TI 2515/194-03.01 - VII (Part 1)
Based on discussions with the licensee staff, review of available design, testing, grid data monitoring results documentation, and walkdowns of installed equipment, the inspectors had reasonable assurance the licensee appropriately implemented the VII. The inspectors determined:
- (1) Open phase conditions will be detected and alarmed in the control rooms on the 1SA14 common annunciator panel for CT-1, 2SA14 common annunciator panel for CT-2, 3SA19 common annunciator panel for CT-3, SA8 common annunciator panel for CT-5, and Keowee Transformer #1 common annunciator panel for Keowee KMSU.
- (2) Detection circuits will be sensitive enough to identify an open phase condition for all credited loading conditions for installed equipment.
- (3) No Class-1E circuits were being replaced with non-Class 1E circuits in the design.
- (4) The updated final safety analysis report (UFSAR) has been prepared to discuss the design features and analyses related to the effects of, and protection for, and open phase condition (OPC) design vulnerability.
Assessment 2515/194 Protective Actions Criteria: TI 2515/194-03.01 - VII (Part 1)
Based on discussions with the licensee staff, review of available design, testing, grid data monitoring results documentation, and walkdowns of installed equipment, the inspectors had reasonable assurance the licensee appropriately implemented the VII. The inspectors determined:
- (1) Five transformers were susceptible to an open phase condition and the licensee had installed detection and mitigating equipment for all five.
- (2) With an open phase condition present and with or without an accident condition signal, the open phase design would not adversely affect the function of important-to-safety systems, structures, or components. The licensees open phase condition design solution added two Power System Sentinel Technologies systems on the start-up transformers CT-1, CT-2, CT-3, CT-5 and KMSU. The trip function, if and when enabled, will provide an additional input to the associated transformer output breakers and input switches to CT-5. The credited plant response is unaffected and will be the same regardless of the conditions that generated the trip of the transformer output breakers.
Assessment 2515/194 Detection, Alarms, and General Criteria Exceptions: TI 2515/194-03.01 - VII (Part 1)
The inspectors identified the following exceptions to the Temporary Instruction criteria resulting from the operating status of the design modifications:
- (1) The licensees design was operating in the monitoring mode with already established setpoints and gathering data to ensure the open phase condition design and protective schemes would minimize mis-operation, or spurious actions in the range of voltage unbalance normally expected in the transmission system. The licensee developed engineering calculations applied to the open phase detection and protection (OPDP) system to protect important-to-safety equipment during an open phase condition. These calculations are included in calculations OSC-11621, Oconee Nuclear Station Open Phase Vulnerability Analysis, Rev 003 and OSC-4300, (ELEC) Protective Relay Settings, Rev. 034.
- (2) A draft of the proposed changes to the Units 1, 2, and 3 and Keowee Hydro Generating Plant UFSARs were available for the inspectors review and included information related to open phase conditions that describe the functions of the OPDP system.
Assessment 2515/194 Protective Actions Criteria Exceptions: TI 2515/194-03.01 - VII (Part 1)
The inspectors identified the following exceptions to the Temporary Instruction criteria resulting from the operating status of the design modifications:
- (1) The licensees open phase condition design solution uses Power System Sentinel Technologies systems to detect, alarm, and provide a trip signal input to the associated startup transformers CT-1, CT-2, and CT-3, KMSU, and the 100 kV Auxiliary Transformer CT-
5. Upon open phase trip signal, if enabled, the existing undervoltage relays would operate to
initiate starting of the alternate power sources to restore power to the bus.
The trip function input to the transformer load side breakers have not been installed and remained deactivated and disconnected during the onsite system implementation inspection and that design function was not able to be demonstrated.
- (2) Periodic tests, calibrations, setpoint verifications or inspections (as applicable) have been established for system operations at present. The surveillance requirements have been maintained for the plant technical specifications (TSs) in compliance with the provisions of 10 CFR 50.36.
Observation: OPC NRC Inspection Comments 2515/194 The inspectors identified the following observations:
- (1) The trip function capabilities for all OPDP systems on CT-1, CT-2, CT-3 and KMSU have not been enabled by the positioning of the OPDP cabinet trip output knife switches (FT1-1 and FT1-2) and by missing final connections to the transformer output breaker trip signal wiring not run into 4.16kV switchgear specific breaker compartments.
- (2) During the NRC inspection, testing had been performed by the transmission line system controllers, which caused a 230 kV and 100 kV lines disturbance that propagated throughout the grid system and caused:
a) Open Phase Detection Protection system alarms in both channels of CT-1 and CT-2.
b) Open phase Alarm Lockout Relay in channel 2 on CT-3.
c) Open phase Alarm Lockout Relay in channel 1 on KMSU.
d) Injection abnormal alarm light of channels 1 and 2 on CT-5.
All alarms were reset after operations was able to investigate and establish the alarms were not an actual open phase condition at the site.
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
- On October 10, 2019, the inspectors presented the Temporary Instruction 2515/194 open phase condition inspection results to Mr. Paul Fisk and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
2515/194
Calculations
OSC-11621
Oconee Nuclear Station Open Phase Vulnerability Analysis
Rev. 003
OSC-11632
Evaluation of Oconee Keowee Motor Protective Device Trip
Times During Open Phase Conditions
Rev. 000
OSC-11665
Evaluation of Oconee Motor Protective Device Trip Times
During Open Phase Conditions
Rev. 001
OSC-11804
Evaluation of Oconee Motor Protective Device trip Times
During Open Phase Conditions
Rev. 001
OSC-4300
(ELEC) Protective Relay Settings
Rev. 034
Corrective Action
Documents
2198906
Unit 3 Start-Up Transformer (CT3) Open Phase Protection
Equipment Installation & Tie-Ins (EC 407343)
Rev. 003
2199933
Unit 1 Start-Up Transformer (CT1) Open Phase Protection
Equipment Installation & Tie-Ins (EC 407344)
Rev. 002
219641
Transformer (CT5) Open Phase Protection Equipment
Installation & Tie-ins
Rev. 000
230308
Unit 2 Start-Up Transformer (CT2) Open Phase Protection
Equipment Installation & Tie-Ins (EC 408968)
Rev. 004
232693
Open Phase OE - Vendor issue requires a change in design
09/24/2019
287757
CT1 Channel 2 Open Phase Trouble Alarm
08/20/2019
288239
Open Phase Setting Adjustments based on AR 02287320
08/22/2019
289311
Keowee Open Phase High Temp Alarm
08/28/2019
290657
CT2 Open Phase Trouble Common Alarm In
09/07/2019
295815
2019 NRC TI-194 OPP - Drawing Change to O-700
10/07/2019
296030
Open Phase Relay Alarms Received CT1, CT2, CT3, CT5,
and KHU
10/08/2019
296110
No guidance in the ARG's to reset invalid Open Phase
alarms
10/09/2019
Drawings
K-0700
One Line Diagram - Relays & Meters - 13.8 to 230 kV
Rev. 044
KEE-0017-01-A
Elementary Diagram Transformer Differential (Keowee Hydro
Station)
Rev. 3A
O-0700
One Line Diagram - Relays & Meters - 19 kV
Rev. 039
O-0800-E
One Line Diagram AC Elementary Diagram 3 Line Conn.
Diag. Transf. Nos. CT5 & OCB, #101
Rev. 020
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
O-1700
One Line Diagram - Relays & Motors - 19 kV
Rev. 040
O-2700
VTO One Line Diagram - Relays & Meter 19 kV
Rev. 030
OEE-71-1A
Elementary Diagram Start-Up Transf. No. CT2 Diff. Lock-Out
Rev. 8C
OEE-71-3
Elementary Diagram Contact Development Start-Up Transf.
No. CT3 Diff. Lock-Out
Rev. 13C
OEE-71-A
Elementary Diagram Start-Up Transf. No. CT1 Diff. Lock-Out
Rev. 5C
OEE-79-1
Elementary Diagram Transf. No. CT5 Diff. Lockout
Rev. 5C
Engineering
Changes
30 Figure 1. CT5 OPP Power Supply One Line
Rev. 003
34 Short Circuit Analysis
Rev. 003
Keowee Open Phase Protection Equipment Installation &
Tie-Ins
Rev. 010
CT5 Open Phase UPS
Rev. 003
Figure 1 - Simplified One-Line of the OPP System Power
Circuit (Attachment 5)
Rev. 001
Miscellaneous
UFSAR Markup Chapter 8 (Section 8.2.2 - CT5)
Rev. 000
IEGR-MN-1602
Analog Open Phase Protection (OPP) System Operating and
Maintenance Manual Oconee
11/28/2018
OSC -11739
ONS Unit 3 Startup Transformer (CT3) Open Phase
Protection (OPP) Failure Modes and Effects Analysis
(FMEA) and Single Failure Analysis (SFA)
Rev. 002
OSC-11664
ONS Unit 2 Startup Transformer (CT2) Open Phase
Protection (OPP) Failure Modes And Effects Analysis
(FMEA) And Single Failure Analysis (SFA)
Rev. 002
OSC-11740
ONS Unit 1 Startup Transformer (CT1) Open Phase
Protection (OPP) Failure Modes and Effects Analysis
(FMEA) and Single Failure Analysis (SFA)
Rev. 002
OSC-11763
Keowee Main Step-Up Transformer (KMSU) Open Phase
Protection (OPP) Failure Modes and Effects
Rev. 001
Procedures
OP/0/A/2000/043
KHS Shift Turnover And Rounds
Rev. 052
OP/2/A/1102/020
D
SSF and Outside Rounds
Rev. 091
Work Orders
209404
500KCMIL Cable from H0 Bushing to OPP SYS (41), SAT
Testing (77), Commissioning (80), 500 KCMIL Cable from
05/13/2019
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
OPP Cabinets to Ground (82).
219890
Connect Neutral/Gnd. Cable to Ground Mat (50), Connect
500 MCM Cable at CT5 HO Bushing (51), Perform Trip
Functional Verifications (84), Alarm Functional Verification
(85), Regression Testing (86), Circuit Interface Verification
(87).
01/02/2019
224441
EC407344-Assist PSS Tech with SAT Testing (61),
Commissioning (86), Voltage Checks for CT-1 (89)
6/27/2019
20320883
EC411891 - Alarm Testing Of CT-1 UPS/OPP System (63),
Test UPS Time Delay (44, 63), Energized Functional Testing
of CT-1 (61)
09/11/2019