IR 05000317/2021011

Temporary Instruction 2515/194 Inspection Report 05000317/2021011 and 05000318/2021011

ML21210A124
Person / Time
Site:	Calvert Cliffs
Issue date:	07/29/2021
From:	Glenn Dentel NRC/RGN-I/DORS
To:	Rhoades D Exelon Generation Co LLC, Exelon Nuclear
Dentel G
References
IR 2021011
Download: ML21210A124 (8)

Text

July 29, 2021

SUBJECT:

CALVERT CLIFFS NUCLEAR POWER PLANT, UNITS 1 AND 2 -

TEMPORARY INSTRUCTION 2515/194 INSPECTION REPORT 05000317/2021011 AND 05000318/2021011

Dear Mr. Rhoades:

On July 14, 2021, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Calvert Cliffs Nuclear Power Plant, Units 1 and 2 and discussed the results of this inspection with Mr. Thomas Haaf, 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, Digitally signed by Glenn T. Glenn T. Dentel Date: 2021.07.29 Dentel 09:27:26 -04'00'

Glenn T. Dentel, Chief Engineering Branch 2 Division of Operating Reactor Safety Docket Nos. 05000317 and 05000318 License Nos. DPR-53 and DPR-69

Enclosure:

As stated

Inspection Report

Docket Numbers: 05000317 and 05000318 License Numbers: DPR-53 and DPR-69 Report Numbers: 05000317/2021011 and 05000318/2021011 Enterprise Identifier: I-2021-011-0016 Licensee: Exelon Generation Company, LLC Facility: Calvert Cliffs Nuclear Power Plant, Units 1 and 2 Location: Lusby, MD Inspection Dates: July 12, 2021 to July 14, 2021 Inspectors: A. Patel, Senior Reactor Inspector F. Arner, Senior Reactor Analyst Approved By: Glenn T. Dentel, Chief Engineering Branch 2 Division of Operating Reactor Safety Enclosure

SUMMARY

The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting a Temporary Instruction 2515/194 Inspection at Calvert Cliffs Nuclear Power Plant, 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

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.

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 a 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.

However, all the inspection activities were performed onsite. 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. 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) 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 Calvert Cliffs Nuclear Power Plant, Units 1 and 2.

Calvert Cliffs Nuclear Power Plant has three independent offsite sources (500kV)which provide power via the 13kV station service buses to the appropriate 4 kV safeguard buses. The open phase detection system is designed to protect the offsite power sources from a loss of phase scenario. Eleven SEL relays were installed to provide detection and alarm capability for open phase conditions associated with the three 500kV-13kV service transformers, four voltage regulators, and four 13kV-4kV service transformers. The relays are wired to provide main control room annunciation if a loss of one or two phase conditions is detected or if the associated relays are non-functional.

In lieu of automatic open phase protective actions, Exelon 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 were monitoring the associated power sources and would provide main control room annunciation if a loss of one or two phase conditions was detected or if a relay was non-functional.

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 Exelon is appropriately implementing the voluntary industry initiative at Calvert Cliffs Nuclear Power Plant, Units 1 and 2. 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)(3)] The open phase condition 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 open phase condition design vulnerability.

6. [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

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.

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

EXIT MEETINGS AND DEBRIEFS

The inspectors verified no proprietary information was retained or documented in this report.

• On July 14, 2021, the inspectors presented the Temporary Instruction 2515/194 Inspection results to Mr. Thomas Haaf, Site Vice President and other members of the licensee staff.

DOCUMENTS REVIEWED

Inspection Type Designation Description or Title Revision or

Procedure Date

2515/194 Corrective Action 4434683

Documents 4434789

Resulting from 4434994

Inspection 4435033

4435115

Drawings 1E-001SH0001 Electrical Main Single Line Diagram Revision 54

Engineering ECP-14-000629 Open Phase Detection for P-13000-1 Revision 0

Changes ECP-15-000572 Open Phase Detection for P-13000-2 Revision 0

ECP-17-000022 Open Phase Detection Project Support for Revised Algorithm Revision 0

ECP-17-000029 Calvert Cliffs Electrical Distribution Reliability Improvement Revision 0

Project (EDRIP) 500kV/13.8kV

Miscellaneous CA-MISC-028 Calvert Cliffs Nuclear Power Plant Open Phase Condition Revision 0

Evaluation

Procedures 0C003-ALM Electrical Distribution Control System Panel 0C003 Alarm Revision 0

Manual

1C18-ALM 13kV & 4kV Essential Feeder Bkrs Control Board Alarm Revision 38

Manual

1C19-ALM 13kv & 4kv Essential Feeder Bkrs Control Board Alarm Revision 43

Manual

1C20-ALM 13kv & 4kv Essential Feeder Bkrs Control Board Alarm Revision 37

Manual

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