ML20206K950

Change of Commitment Date for NEI Open Phase Initiative

ML20206K950
Person / Time
Site:	Calvert Cliffs
Issue date:	07/20/2020
From:	Haaf T Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML20206K950 (4)

Text

Exelon Generation Thomas P. Haaf Plant Manager Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs Parkway Lusby, MD 20657 410-495-5205 Office 717-327-7728 Mobile www.exeloncorp.com Thomas.haaf@exeloncorp.com July 20, 2020 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2 Renewed Facility Operating License Nos. DPR-53 and DPR-69 NRC Docket Nos. 50-317 and 50-318

Subject:

Change of Commitment Date for NEI Open Phase Initiative

Reference:

1. Letter from G. H. Gell rich (CCNPP) to Document Control Desk (NRC), dated January 31, 2014, Response to Request for Additional Information Regarding Response to Bulletin 2012-01, "Design Vulnerability in Electric Power System"

2. Letter from M. D. Flaherty (CCNPP) to Document Control Desk (NRC), dated August I 6, 2018, Change of Commitment Date for NEI Open Phase Initiative In Reference 1, Calvert Cliffs Nuclear Power Plant (Calvert Cliffs) committed to the generic schedule provided in the industry Open Phase Condition initiative. Also in Reference 1, Calvert Cliffs additionally stated that the planned schedule for implementation of the Open Phase Condition (OPC} Detection system may be revised based on various factors. The purpose of this letter is to notify the NRC of changed to the implementation schedule for the OPC initiative actions for Calvert Cliffs. Specifically, Calvert Cliffs plans to defer the implementation from March 31, 2021 to June 30, 2021.

Calvert Cliffs selected the OPC Detection system that was developed by Schweitzer Engineering Laboratory (SEL). This system was installed in each Calvert Cliffs' Unit as previously committed.

Reference 2 changed the commitment date because of the Electrical Distribution Reliability Improvement Project where Calvert Cliffs installed a third 13 kV service transformer. Installation included the addition of several new 13 kV buses. The original schedule was to complete the tie in after the 2020 Unit 1 Refueling Outage. Delays resulted in the completion of the project not being completed until June 30, 2020 .. The addition of the new service transformer and associated buses required changes to the existing OPC detection algorithm. Installation impacting the existing OPC equipment began in Fall of 2018 and was completed on June 30, 2020. Calvert Cliffs has begun a new OPC detection monitoring period. The new monitoring period.would conclude in June of 2021.

Document Control Desk July 20, 2020 Page 2 The new monitoring period will not adversely impact the safe operation of Calvert Cliffs Units 1 and 2.

Calvert Cliffs has taken interim corrective actions in response to this industry issue, as documented in Reference 1. As part of these interim corrective actions, Calvert Cliffs continues to maintain 13 kV and 4 kV vital bus voltmeters in position "3-1" (A-C phase) to allow Calvert Cliffs operating crews to identify the precursors for an open phase. Additionally, the installed OPC detection system alarm feature helps operators diagnose any potential open phase condition in offsite power. This feature will remain in operation, if available, during the modifications to the electrical system. Periodic walkdowns of the switchyard and transformer yard are performed and include inspections to ensure that parameters are within expected limits.

This commitment change is processed in accordance with the Nuclear Energy Institute guidance for deviations to the Open Phase Condition initiative and NEI 99-04, "Guidelines for Managing NRC Commitment Changes." Attachment (1) describes the changed commitment.

Should you have questions regarding this matter, please contact Mr. Larry D. Smith at (410) 495-5219.

Respectfully, Thomas P. Haaf Site Vice President TPH/KG/lmd

Attachment:

(1) Summary of Regulatory Commitments cc: NRC Project Manager, Calvert Cliffs NRC Resident Inspector, Calvert Cliffs NRC Regional Administrator, Region I S. Seaman, MD-DNR

ATTACHMENT (1)

SUMMARY

OF REGULATORY COMMITMENTS Calvert Cliffs Nuclear Power Plant July 20, 2020

ATTACHMENT (1)

SUMMARY

OF REGULATORY COMMITMENTS The following table identifies commitments made in this document. (Any other actions discussed in the submittal represent intended or planned actions. They are described to the NRC for the NRC's information and are not regulatory commitments.)

COMMITTED COMMITMENT TYPE COMMITMENT DATE OR One-Time Action Programmatic "OUTAGE" (Yes/No) (Yes/No)

Full implementation of the NEl Open June 30, 2021 Yes No Phase Initiative 1