ML20314A164

Spring 2020 180-Day Steam Generator Report (EPID-L-2020-LRO-0049)

ML20314A164
Person / Time
Site:	Calvert Cliffs
Issue date:	11/19/2020
From:	Marshall M NRC/NRR/DORL/LPL1
To:	Bryan Hanson Exelon Generation Co, Exelon Nuclear
Marshall, Michael L.
References
EPID L-2020-LRO-0049
Download: ML20314A164 (3)

Text

November 19, 2020 Mr. Bryan C. Hanson Senior Vice President Exelon Generation Company, LLC President and Chief Nuclear Officer Exelon Nuclear 4300 Winfield Road Warrenville, IL 60555

SUBJECT:

CALVERT CLIFFS NUCLEAR POWER PLANT, UNIT 1 - SPRING 2020 180-DAY STEAM GENERATOR REPORT (EPID L-2020-LRO-0049)

Dear Mr. Hanson:

By letter dated August 10, 20191 (Agencywide Documents Access and Management System Accession No. ML20227A109), Exelon Generation Company, LLC (the licensee) submitted information summarizing the results of the spring 2020 steam generator (SG) inspections performed at Calvert Cliffs Nuclear Power Plant, Unit 1. The inspections were performed during refueling outage (RFO) 25.

The licensee provided the scope, extent, methods, and results of the SG tube inspections in the letter referenced above. In addition, the licensee described corrective actions (e.g., tube plugging), if any were taken in response to the inspection findings. Based on the review of the information provided, the U.S. Nuclear Regulatory Commission (NRC) staff has the following observations:

The reporting threshold for fan bar wear was increased from 5 percent through-wall to 7 percent through-wall in RFO 25. Seven new fan bar wear indications were identified during RFO 25 (four in SG11 and three in SG12).

Eight lattice grid support wear indications were identified during RFO 25 (six in SG11 and two in SG12). Seven of the eight were reported in the prior inspection (RFO 23).

Seventeen foreign object wear indications in fifteen tubes were identified during RFO 25 (five in SG11 and twelve in SG12). Fourteen of the indications were reported in prior outages, and the licensee reported that they showed no noticeable change in wear depth using +Point'. The licensee also reported that the foreign objects are no longer present.

Based on a review of the information provided, the NRC staff concludes that the licensee provided the information required by its technical specifications. In addition, the staff concludes that there are no technical issues that warrant follow-up action at this time, since the inspections appear to be consistent with the objective of detecting potential tube degradation, and the 1 The letter transmitting the spring 2020 SG report was dated August 10, 2019. The year appears to be a typographical error.

inspection results appear to be consistent with industry operating experience at similarly designed and operated units.

If you have any questions, please contact me at (301) 415-2871 or by e-mail to Michael.Marshall@nrc.gov.

Sincerely,

/RA/

Michael L. Marshall, Jr., Senior Project Manager Plant Licensing Branch I Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-317 cc: Listserv

ML20314A164

• by e-mail OFFICE NRR/DORL/LPL1/PM* NRR/DORL/LPL1/LA* NRR/DNRL/NCSG/BC* NRR/DORL/LPL1/BC*

NAME MMarshall LRonewicz SBloom JDanna DATE 11/09/2020 11/09/2020 11/06/2020 11/19/2020 OFFICE NRR/DORL/LPL1/PM*

NAME MMarshall DATE 11/19/2020