IR 05000387/2020010
| ML20056E215 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 02/21/2020 |
| From: | Glenn Dentel Engineering Region 1 Branch 2 |
| To: | Berryman B Susquehanna |
| Dentel G | |
| References | |
| IR 2020010 | |
| Download: ML20056E215 (8) | |
Text
February 21, 2020
SUBJECT:
SUSQUEHANNA STEAM ELECTRIC STATION, UNITS 1 AND 2 -
TEMPORARY INSTRUCTION 2515/194 INSPECTION REPORT 05000387/2020010 AND 05000388/2020010
Dear Mr. Berryman:
On February 5, 2020, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Susquehanna Steam Electric Station, Units 1 and 2 and discussed the results of this inspection with Mr. Kevin Cimorelli, 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,
/RA/
Glenn T. Dentel, Chief Engineering Branch 2 Division of Reactor Safety
Docket Nos. 05000387 and 05000388 License Nos. NPF-14 and NPF-22
Enclosure:
As stated
Inspection Report
Docket Numbers:
05000387 and 05000388
License Numbers:
Report Numbers:
05000387/2020010 and 05000388/2020010
Enterprise Identifier: I-2020-010-0014
Licensee:
Susquehanna Nuclear, LLC
Facility:
Susquehanna Steam Electric Station, Units 1 and 2
Location:
Berwick, PA
Inspection Dates:
February 3, 2020 to February 5, 2020
Inspectors:
S. Elkhiamy, Reactor Inspector
R. Pinson, Reactor Inspector
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 Temporary Instruction 2515/194 at Susquehanna Steam Electric 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 Susquehannas implementation of the Nuclear Energy Institutes voluntary industry initiative in compliance with Commission guidance. The inspectors discussed Susquehannas open phase condition system design and ongoing implementation plans with plant staff. The inspectors reviewed Susquehanna and vendor documentation, and performed system walkdowns to verify that the installed equipment was supported by the design documentation. Susquehanna had recently completed physical installation and the equipment was being operated in a monitoring mode with the trip functions disabled.
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. ML15075A454) dated March 16, 2015. 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) Susquehanna Nuclear selected the open phase detection system designed and manufactured by PSSTech as the design vendor for the open phase condition system at Susquehanna Steam Electric Station. The open phase protection system is designed to protect the offsite power sources from a loss of phase condition. Startup Transformers T10 and T20 provide two 230 kV independent offsite power sources to the Susquehanna station from the bulk power system. Startup Transformers T10 and T20 provide offsite power for the Engineered Safeguard Auxiliary buses through 13.8kV Start Up Bus 10 (OA103) and Bus 20 (OA104). Four PSStech Open Phase Detection (OPD) systems have been installed on the high side of Startup Transformers 10 and 20 and are designed to trip the respective transformer T10 lockout relay 86A 1-10301 B or T20 lockout relay 86A 1-10401 B and initiate protective switching actions to restore power to the vital buses, upon detection of an open phase.
The relays are wired to provide annunciation and are configured to trip the associated power sources if a loss of phase condition is detected. Alarms from the Open Phase Detection systems, including open phase condition alarms and panel trouble alarms, are annunciated in the control room at the "Start Up XFMR Trouble" alarm windows via the transformer's control panel. Additionally, the status of Individual Open Phase Detection system alarm conditions (including open phase detected, channel injection abnormal, and Injection source failure) are available on the plant process computer system.
At the end of the inspection, the PSSTech system was in the alarm only mode of operation. The relay trip circuits were isolated from the lockout relays by leaving the associated mode switches set to alarm only. Susquehanna Nuclear plans to pursue an alternate implementation method (i.e. risk based with manual actions) for Unit 1 and Unit 2 to comply with the open phase detection initiative.
INSPECTION RESULTS
Temporary Instruction 2515/194-03.01 - Voluntary Industry Initiative 2515/194 Based on discussions with Susquehanna staff, review of design and testing documentation, and walkdowns of installed equipment, the inspectors had reasonable assurance that the Susquehanna staff is appropriately implementing, with noted exceptions discussed below, the voluntary industry initiative at Susquehanna Station. The inspectors determined that:
Detection, Alarms and General Criteria
1. Detection circuits will be sensitive enough to identify an open phase condition for all
credited loading condition. 03.01(a)(2)
2. No Class 1E circuits were being replaced with non-Class 1E circuits in this design.
03.01(a)(4)
Protective Actions Criteria
1. The identified offsite power sources are susceptible to an open phase condition and
the licensee was implementing design changes to mitigate the effects. 03.01(b)(1)
2. With an open phase condition present and no accident condition signal, the licensee
determined there would be no adverse impact to important-to-safety equipment due to the open phase condition. The licensee performed an analysis demonstrating that during an open phase condition, important-to-safety equipment would remain powered at levels above current protective relaying setpoints and would not be damaged.
03.01(b)(2)
No findings were identified.
Detection, Alarms and General Criteria Exceptions 2515/194 03.01(a)(1) The licensee has implemented (EPRI) - PSSTech design system which is used for detection, alarm, and actuation (mode switch in alarm-only). Unit 2 Main Control Room alarm is currently non functional due to grounding and switching issues identified by the licensee (CRs 2018-14617 and 2018-14684). During the inspection, the inspectors identified that the compensatory measures on the startup bus associated with T20 were not being performed; specifically individual phase checks. CR 2020-01918 was written to address this condition. The local transformer panel alarms remained functional and operators performed daily rounds and would likely identify an open phase condition.
03.01(a)(3) The licensees design installation was essentially complete and was in the middle of completing a monitoring period with the alarms in operation to ensure the open phase condition design and protective schemes would minimize misoperation or spurious actions in the range of voltage unbalance normally expected in the transmission system. During the monitoring phase, the licensee experienced spurious nuisance alarms (CR 2017-18224) and is working with the vendor to resolve, and establish new trip setpoints. The inspectors were unable to verify that the actuation circuit design does not result in lower overall plant operation reliability since this requires the system to be in operation with final trip setpoints established.
03.01(a)(5) The Updated Final Safety Analysis Report has been updated to include information related to open phase conditions; however the licensee has plans to pursue an alternate implementation method to comply with the open phase detection initiative, which will require further updates.
Protective Actions Exceptions 2515/194 03.01(b)(3) Inspectors determined that with an open phase condition and an accident condition signal present, the open phase detection system would not adversely affect the function of the load shedding and sequencing system to provide a means of disconnecting and sequencing of loads on the safety-related buses. Features to automatically detect and isolate an open phase condition have been installed, but the automatic actuation of the system has been bypassed on both the T-10 and T-20 transformers while in the monitoring period.
03.01(b)(4) Periodic testing, preventive maintenance, and surveillance activities have not been established for the open phase protective features associated with the T-10 and T-20 transformers. The licensee has documented the need to evaluate for any required periodic testing or preventive maintenance activities in DI-2016-19710.
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
- On February 5, 2020, the inspectors presented the NRC inspection results to Mr. Kevin Cimorelli, 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
CR 2017-18224
CR 2018-14617
CR 2018-14684
DI-2016-19710
Corrective Action
Documents
Resulting from
Inspection
CR 2020-01901
Missing safety switch label plate
CR 2020-01904
Incorrect ON procedure reference for Alarm Response
CR-2020-01868
Failure to obtain properly closed out ODM IAW NDAP-QA-
0333.
CR-2020-01918
Missing NPO documentation addressing SUB-20 phase
current checks
CR-2020-01929
Exceptions Identified During NRC OPC Inspection
Engineering
Changes
EC-003-1006
Evaluation of SSES Electrical Distribution System to Open
Phase Conditions (Open Phase Study)
EC-004-1031
Plant AC Loadflow Analysis
Miscellaneous
ODM for offsite power source open circuit single event
5/24/2012
CSD-OPD-006
Open Phase Detection System Basis of Design
11/18/2019
IOM-1401
Open Phase Protection System Operating and Maintenance
Manual
7/28/2017
LDCN-5305
Open Phase Detection & Protection Alarm Only Enable for
Startup Transformer T10
LDCN-5312
Open Phase Detection & Protection Alarm Only Enable for
Startup Transformer T20
1