IR 05000220/2021011
| ML21124A027 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 05/04/2021 |
| From: | Glenn Dentel Division of Operating Reactors |
| To: | Rhoades D Exelon Generation Co |
| References | |
| IR 2021011 | |
| Download: ML21124A027 (9) | |
Text
May 4, 2021
SUBJECT:
NINE MILE POINT NUCLEAR STATION - TEMPORARY INSTRUCTION 2515/194 INSPECTION REPORT 05000220/2021011 AND 05000410/2021011
Dear Mr. Rhoades:
On April 20, 2021, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Nine Mile Point Nuclear Station and discussed the results of this inspection with Mr. Pete Orphanos, Site Vice President and other members of your staff. The results of this inspection are documented in the enclosed report.
No findings or violations of more than minor significance were identified during this inspection.
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 Title 10 of the Code of Federal Regulations 2.390, Public Inspections, Exemptions, Requests for Withholding.
Sincerely, X
/RA/
Signed by: Glenn T. Dentel
Glenn T. Dentel, Chief Engineering Branch 2 Division of Operating Reactor Safety
Docket Nos. 05000220 and 05000410 License Nos. DPR-63 and NPF-69
Enclosure:
As stated
Inspection Report
Docket Numbers:
05000220 and 05000410
License Numbers:
Report Numbers:
05000220/2021011 and 05000410/2021011
Enterprise Identifier: I-2021-011-0015
Licensee:
Exelon Nuclear
Facility:
Nine Mile Point Nuclear Station
Location:
Oswego, NY
Inspection Dates:
April 12, 2021 to April 20, 2021
Inspectors:
C. Hobbs, Reactor Inspector
D. Werkheiser, Senior Reactor Analyst
Approved By:
Glenn T. Dentel, Chief
Engineering Branch 2
Division of Operating Reactor Safety
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting a Temporary Instruction 2515/194 Inspection at Nine Mile Point 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)
The inspectors reviewed the licensees implementation of the Nuclear Energy Institute Voluntary Industry Initiative on Open Phase Condition, (ADAMS Accession No. ML19163A176)dated June 6, 2019. This included reviewing how the licensee updated their licensing basis to reflect the need to protect against Open Phase Conditions.
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) Exelon selected the Open Phase Condition (OPC) detection system designed and manufactured by Schweitzer Engineering Laboratories (SEL) for use at Nine Mile Point Nuclear Station. The offsite power distribution system at Nine Mile Point Unit 1 and Unit 2 is described below.
Nine Mile Point Unit 1 has two 115 kV independent offsite power sources, Line 1 and Line 4. Line 1 is supplied from the South Oswego substation, while Line 4 is supplied from the Lighthouse Hill substation through the James A. Fitzpatrick Switchyard.
115 kV power is then supplied to circuit breakers R10 and R40, which then supply power to Reserve Transformers T101-North, and T101-South. Power is then supplied to the 4kV emergency buses, PB-102 and PB-103. OPC detection is provided in 4 locations: at the R10 and R40 115 kV circuit breakers, and at the T101-North and T101-South transformers.
Nine Mile Point Unit 2 also has two 115 kV independent offsite power sources, Line 5 and Line 6. Line 5 is supplied power from the 345 kV transformer TB-1 located in the Scriba switchyard. Line 6 is supplied power from the 345 kV transformer TB-2 which is also located in the Scriba switchyard. Line 5 and Line 6 supply 115 kV power to Reserve Station Service Transformers, Reserve Transformer A, and Reserve Transformer B. The Auxiliary Boiler Transformer is a third transformer, that may be supplied from either Line 5 or Line 6. The Auxiliary Boiler Transformer may be used as a backup source of power to the 4kV emergency buses. Power is supplied to the three 4kV emergency buses, 2ENS-SWG101, 2ENS-SWG102, and 2ENS-SWG103 from Reserve Transformer A, and Reserve Transformer B. OPC detection is provided in 5 locations: at the TB-1 and TB-2 transformers in the Scriba switchyard, at Reserve Transformer A, at Reserve Transformer B, and at the Auxiliary Boiler Transformer.
In lieu of automatic OPC protective actions, Nine Mile Point Unit 1 and Unit 2 implemented an alarm only strategy, which relies on proper operator actions to diagnose and respond to an Open Phase Condition. At the end of this inspection, the SEL relays for OPC were monitoring the associated power sources and would provide main control room annunciation if a loss of one or two phases of power was detected, or if an OPC relay was non-functional. In addition, actuation of an OPC relay will also be indicated on alarms in the plant process computer.
INSPECTION RESULTS
Observation: Temporary Instruction 2515/194 - Section 03.01(a) and
- (c) Results 2515/194 Based on discussions with Exelon staff, review of design and testing documentation, and walkdowns of installed equipment, the inspectors had reasonable assurance that Nine Mile Point Nuclear Station is implementing the guidance specified in the NEI Voluntary Industry Initiative on Open Phase Condition, with a noted exception discussed below. The inspectors verified the following criteria:
Detection, Alarms and General Criteria
1. [03.01(a)(1)] OPCs are detected and alarmed in the control room.
2. [03.01(a)(2)] In scenarios where automatic detection may not be possible due to very
low or no load conditions, or when transformers are in a standby mode, detection will occur as soon as loads are transferred to the standby source. Additionally, where detection is not reliable, Exelon has established monitoring requirements on a per shift basis, to look for evidence of an OPC.
3. [03.01(a)(3)] The OPC design and protective schemes minimize misoperation or
spurious action in the range of voltage unbalance normally expected in the transmission system that could cause separation from an operable off-site power source. Additionally, Exelon has demonstrated that the actuation circuit design does not result in lower overall plant operation reliability.
4. [03.01(a)(4)] No Class-1E circuits were replaced with non-Class-1E circuits in this
design.
5. [03.01(a)(5)] The Updated Final Safety Analysis Report was updated to discuss the
design features and analyses related to the effects of any OPC design vulnerability.
Use of Risk-Informed Evaluation Method
1. [03.01(c)(1)] The plant configuration matched the Probabilistic Risk Assessment
(PRA) model to address an OPC, and the logic of the PRA model is sound.
2. [03.01(c)(2)] The procedures which validate that an OPC alarm would identify the
proper indication to validate the OPC at all possible locations.
3. [03.01(c)(3)] Observations associated with procedures and operator actions required
to respond to an OPC alarm and potential equipment trip match the Human Reliability Analysis (HRA).
4. [03.01(c)(4)] Sensitivity analyses used in the Nine Mile Point Unit 1 and Unit 2 PRA
analysis for using Operator Manual Actions (OMAs) in leu of OPC automatic protective relay actuation, did not exceed the thresholds defined in the NEI 19-02 guidance document for delta Core Damage Frequency (CDF) or delta Large Early Release Frequency (LERF).
5. [03.01(c)(5)] Assumptions, procedures, and operator actions specified in the Nine Mile
Point Unit 1 and Unit 2 NEI 19-02 analysis are consistent with the plant-specific design and licensing basis, including:
- (a) Initiating events considered in the analysis.
- (b) Boundary conditions specified in Attachment 1 of the NEI Voluntary Industry Initiative, Revision 3.
- (c) Operating procedures for steps taken to recover equipment assumed tripped, locked out, or damaged due to an OPC.
- (d) Where recovery was assumed in the PRA analysis for tripped electric equipment, restoration of the equipment was based on analyses that demonstrate that automatic isolation trips did not result in equipment damage.
Observation: Temporary Instruction 2515/194 - Detection, Alarms, and General Criteria - Exception 2515/194
[03.01(a)(6)] - Identify if Open Phase Isolation System (OPIS) detection and alarm components are maintained in accordance with station procedures or maintenance program, and that periodic tests, calibrations, setpoint verifications, or inspections (as applicable) have been established.
Exception - Nine Mile Point Unit 2 had not developed any maintenance PMs for the OPC relays on Unit 2 at the beginning of the inspection. Nine Mile Point Unit 1 had developed maintenance PMs for Unit 1 OPC relays at the beginning of the inspection. This deviation was identified in a pre-inspection self-assessment performed by Exelon and captured in the corrective action program as Issue Report 04405714. At the end of the inspection, Issue Report 02540320-06 was created to develop maintenance PMs for Nine Mile Point Unit 2 OPC relays.
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
- On April 20, 2021, the inspectors presented the Temporary Instruction 2515/194 inspection results to Mr. Pete Orphanos, Site Vice President and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
2515/194
Corrective Action
Documents
2540320,
217412,
292365,
296560,
296567,
298487,
298493,
4369561,
4405714
Corrective Action
Documents
Resulting from
Inspection
4416368
Drawings
C-19420-C
Nine Mile Point Unit 1 Elementary Wiring Diagram 115 kV
Line #1, South Oswego, Control Circuits, Sheet 01A
Revision 1
C-19421-C
Nine Mile Point Unit 1 Elementary Wiring Diagram 115 kV
Line #4, NMP-FITZ., Control Circuits, Sheet 1A
Revision 8
C-19422-C
Nine Mile Point Unit 1 Elementary Wiring Diagram 115 kV
Reserve Transforms 101N & 101S Open Phase Protection,
Sheet 01A
Revision 0
C-19422-C
Nine Mile Point Unit 1 Elementary Wiring Diagram 115 kV
Reserve Transforms 101N & 101S Open Phase Protection,
Sheet 01B
Revision 0
C-34857-C
Nine Mile Point Unit 1 Elementary Wiring Diagram, Auxiliary
Control Cabinet 1S79, Alarm Relay 74A, Sheet 2
Revision 9
ESK 08SPR005
Nine Mile Point Unit 2 D.C. Elementary Diagram XFMR
2RTX-XSR1A, Primary Protection, Sheet 2
Revision 0
Engineering
Changes
ECP-14-000340
Nine Mile Point Unit 1 Open Phase Relaying for
Transformers XF-101S and XF-101N
Revision 1
ECP-14-000922
Nine Mile Point Unit 2 Open Phase Detection System
Implementation
Revision 2
ECP-16-000021
Nine Mile Point Unit 1 Open Phase Detection Implementation
Revision 0
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Engineering
Evaluations
N1-MISC-010
Nine Mile Point Station Unit 1 Open Phase Condition
Evaluation
Revision 0
N2-MISC-015
Nine Mile Point Station Unit 2 Open Phase Condition
Evaluation
Revision 1
Miscellaneous
Nine Mile Point Unit 1 UFSAR change number 1-19-UFS-003 dated
2/19/19
Nine Mile Point Unit 2 UFSAR change number 2-19-UFS-006 dated
2/19/19
Nine Mile Point Nuclear Station, Units 1 and 2 - Temporary
Instruction Report 05000220/2019014 and
dated
2/9/19
Presentation
TI-2515/194 Open Phase NRC Inspection
dated
4/12/21
Procedures
N1-ARP-A8
Nine Mile Point Unit 1 Panel A8 Alarm Response Procedures
01900
N1-PM-S1
Nine Mile Point Unit 1 Operator's Rounds Guide
03800
N2-ARP-852600
Nine Mile Point Unit 2 2CEC*PNL852 Series 600 Alarm
Response Procedures
01400
N2-OP-70
Nine Mile Point Unit 2 Station Electrical Feed and 115 kV
2600
Self-Assessments PI-AA-126-1001
NRC Open Phase Inspection TI 2515/194 Self-Assessment
dated 3/5/21