IR 05000352/2020015
| ML21004A133 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 01/04/2021 |
| From: | Glenn Dentel Engineering Region 1 Branch 2 |
| To: | Rhoades D Exelon Generation Co, Exelon Nuclear |
| Dentel G | |
| References | |
| EPID I-2020-015-0003 IR 2020015 | |
| Download: ML21004A133 (8) | |
Text
January 4, 2021
SUBJECT:
LIMERICK GENERATING STATION, UNITS 1 AND 2 - TEMPORARY INSTRUCTION 2515/194 INSPECTION REPORT 05000352/2020015 AND 05000353/2020015
Dear Mr. Rhoades:
On December 10, 2020, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Limerick Generating Station, Units 1 and 2 and discussed the results of this inspection with Mr. Frank Sturniolo, 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 Reactor Safety
Docket Nos. 05000352 and 05000353 License Nos. NPF-39 and NPF-85
Enclosure:
As stated
Inspection Report
Docket Numbers:
05000352 and 05000353
License Numbers:
Report Numbers:
05000352/2020015 and 05000353/2020015
Enterprise Identifier: I-2020-015-0003
Licensee:
Exelon Generation Co., LLC
Facility:
Limerick Generating Station, Units 1 and 2
Location:
Sanatoga, PA 19464
Inspection Dates:
December 7, 2020 to December 10, 2020
Inspectors:
L. Dumont, Reactor Inspector
D. Werkheiser, Senior Reactor Analyst
Approved By:
Glenn T. Dentel, Chief
Engineering Branch 2
Division of Reactor Safety
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting a Temporary Instruction 2515/194 inspection at Limerick Generating Station, Units 1 and 2, 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
The inspection was conducted using Temporary Instruction 2515/194 (ADAMS Accession No. ML17137A416), effective November 1, 2017. The inspectors reviewed the licensees implementation of the Nuclear Energy Institutes voluntary industry initiative in compliance with Commission guidance. 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. Starting on March 20, 2020, in response to the National Emergency declared by the President of the United States on the public health risks of the coronavirus (COVID-19), inspectors were directed to begin telework. In addition, regional baseline inspections were evaluated to determine if all or portion of the objectives and requirements stated in the IP could be performed remotely. If the inspections could be performed remotely, they were conducted per the applicable IP. In some cases, portions of an IP were completed remotely and on site. The inspections documented below met the objectives and requirements for completion of the IP.
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, (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 detection system designed and manufactured by Schweitzer Engineering Laboratories (SEL), as the design vendor for the open phase condition system at Limerick Generating Station.
Limerick Generating Station has two independent offsite sources (220 kV and 500 kV) which provide power via the station auxiliary buses to the appropriate 4 kV safeguard buses through the 101 and 201 safeguard transformers. The open phase protection system is designed to protect the 220 kV and 500 kV offsite power sources from a loss of phase scenario. Four SEL relays (260A104 & 105 and 260A204 & 205)were installed to monitor and alarm on each of the 4 offsite source transformers: the 10 station auxiliary transformer (220 kV), 20 regulating transformer (500 kV), and the 101 and 201 safeguard transformers. The relays are wired to provide annunciation if a loss of one or two phase conditions is detected. The loss of phase detection relays for each transformer include main control room annunciation for a trouble alarm associated with the station located relays. The associated substation control house also has annunciation window panels that provide trouble alarms for the relays.
Exelon uses the risk-informed method, which utilizes manual actions for protective action measures. At the end of this inspection the SEL system was monitoring and would alarm the control room if a loss of one or two phase conditions is detected.
INSPECTION RESULTS
Observation: Temporary Instruction 2515/194-03.01 - Voluntary Industry Initiative 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 Exelon is appropriately implementing the voluntary industry initiative at Limerick Generating Station. The inspectors verified the following criteria:
Detection, Alarms and General Criteria
1. [03.01(a)(1)] Open phase conditions 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, automatic detection will occur as soon as loads are transferred to the standby source.
Additionally, where automatic detection is not reliable, Exelon has established monitoring requirements on a per shift basis, to look for evidence of an open phase condition.
3. [03.01(a)(4)] No Class 1E circuits were being replaced with non-Class 1E circuits in
this design.
4. [03.01(a)(5)] The Final Safety Analysis Report was updated to discuss the design
features and analyses related to the effects of any open phase condition design vulnerability.
5. [03.01(a)(6)] The open phase condition detection and alarm components are
maintained in accordance with Exelons procedures or maintenance program, and periodic tests, calibrations setpoint verifications or inspections (as applicable) have been established.
Use of Risk-Informed Evaluation Method
1. [03.01(c)(1)] The plant configuration matched the changes made to the probabilistic
risk assessment model to address an open phase condition, and the logic of the probabilistic risk assessment model changes is sound.
2. [03.01(c)(2)] The procedures which validate that the open phase condition alarm
would identify the proper indication to validate the open phase conditions at all possible locations.
3. [03.01(c)(3)] Observations associated with procedure(s) and operator actions required
to respond to an open phase condition alarm and potential equipment trip match the Human Reliability
Analysis.
4. [03.01(c)(4)] Assumptions listed in the NEI 19-02 Appendix A evaluation and the
sensitivity analyses listed in Section 5 of the evaluation were verified.
5. [03.01(c)(5)] Assumptions, procedures, operator actions, and Exelons analyses
specified above 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 the open phase conditions (or use of alternate equipment)d. Where recovery was assumed in the probabilistic risk assessment 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
No findings or exceptions were identified. Regarding the risk-informed evaluation method criterion 3, Exelon ensured operator actions were properly assessed in the human reliability analysis; however, the inspectors identified that periodic or simulator training were not being performed nor scheduled. Exelon documented this observation as CR-04389349 to evaluate recurring training or supplemental training (JPM and/or simulator).
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
- On December 10, 2020, the inspectors presented the NRC inspection results to Mr. Frank Sturniolo, 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
286033
Corrective Action
Documents
Resulting from
Inspection
04389403
04389349
Drawings
8031
Single Line Diagram Station
Engineering
Changes
0000618105
Engineering
Evaluations
LM-MISC-033
Limerick Open Phase Condition Evaluation
and 1
Procedures
6900E.05B
Determination of 4kV Switchgear Motor Protection
Equipment Classification
GP-19, Appendix
Unit 2 Turbine Equipment Operator Activities
Loss of Single Phase From Offsite Source,
Self-Assessments 04371769
Pre-NRC Inspection OPC Self-Assessment 2020
10/28/20