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At 2045 EST on December 15, 2023, it was determined that the reactor coolant system barrier had a through wall flaw with leakage. The leakage is minor in nature and unquantifiable. The leakage is coming from the welded connection of a vent valve for safety injection tank 2A2 outlet valve rendering both trains of high-pressure safety injection inoperable. The unit is being cooled down to cold shutdown to comply with technical specifications. This event is being reported pursuant to 10 CFR 50.72(b)(3)(ii)(A) and 10 CFR 50.72(b)(3)(v)(D). The NRC Resident Inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The unit was heating up after a maintenance outage. The leak was discovered during mode 3 walkdown.

• * *UPDATE AT 1254 EST ON 02/12/24 FROM B. MURRELL TO T. HERRITY***

The purpose of this notification update is to retract a portion of a previous report, made on 12/16/2023 at 0404 EST (EN 56893). Notification of the event to the NRC was initially made as a result of declaring both trains of unit 2 high pressure safety injection system inoperable due to reactor coolant barrier through wall leak on the vent line for the 2A2 safety injection tank. Subsequent to the initial report, Florida Power and Light has concluded that the through wall leak rate was insignificant, and therefore the safety injection system's safety-related function was maintained. Therefore, this portion of the event is not considered a safety system functional failure and is not reportable to the NRC pursuant 10 CFR 50.72(3)(v)(D). This update does not affect the original 10 CFR 50.72(b)(3)(ii)(A) report for the degraded condition related to the reactor coolant barrier through wall leak. The NRC Resident Inspector has been notified. Notified R2DO (Miller).

The following information was provided by the licensee via email: At 0854 (CDT) on April 23, 2022, while performing volumetric inspections required by ASME Code Case N-729-6, a rejectable indication on Reactor Vessel Head Penetration 75 Core Exit Thermocouple (CETC) was identified. The indication is located inboard of the J-groove weld and is OD-initiated (outer diameter - initiated). This event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(A). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The repair is scheduled during the refueling outage.

• * * UPDATE ON 04/29/22 AT 1112 EDT FROM BRYAN LYKKEBAK TO OSSY FONT * * *

The following information was provided by the licensee via telephone and email: The rejectable indication on Reactor Vessel Head Penetration 75 Core Exit Thermocouple (CETC) initiated on the outside diameter (OD) of the nozzle in an area that was not surface stress mitigated (peened). The indication was found to be acceptable for continued operation under CFR and ASME requirements and will not be repaired during this outage. The licensee notified the NRC Resident Inspector. Notified R3DO (Ziolkowski).

At 1605 EST on 11/12/21, it was determined that the RCS Pressure Boundary does not meet ASME Section XI, Table IWB-341 0-1, 'Acceptable Standards' due to a through wall leak of the Core Exit Thermocouple Nozzle Assembly. Measures have been taken to establish Mode 5 for corrective actions. This event is being reported pursuant to 10 CFR 50.72(b)(3)(ii)(A). The NRC Resident Inspector has been notified.

• * * RETRACTION ON 3/28/2022 AT 0849 EDT FROM DAVID STOIA TO MIKE STAFFORD * * *

The following information was provided by the licensee via email: On 11/12/2021 EN 55574 reported possible evidence of pressure boundary through-wall leakage observed on a Core Exit Thermocouple (CET) tube. On 3/10/2022, based on laboratory analysis of the affected CET tube section, FPL Engineering determined that there was no pressure boundary through-wall leakage associated with this event. Analysis identified that the leakage likely originated from an adjacent threaded compression fitting on a tubing joint. This condition complies with ASME Section XI requirements and is therefore not reportable. This follow-up NRCOC notification is a retraction of EN 55574. The NRC Resident Inspector has been notified. Notified R2DO (Miller).

On September 12, 2021, at 1728 EDT, with Unit 1 in Mode 5 (Cold Shutdown) while performing inspections of the North Anna Power Station Unit 1 reactor vessel head flange area, a weld leak was identified on the reactor vessel flange leak-off line that connects to the flange between the inner and outer head o-rings. Entered TRM 3.4.6 Condition B for ASME Code Class 1,2, and 3 components. With known leakage past the inner head o-ring, this condition is reported since the fault in the tubing is considered pressure boundary (Reactor Coolant System) leakage. This event is reportable in accordance with 10 CFR 50.72(b)(3)(ii)(A) for any event or condition that results in the condition of the nuclear power plant, including its principle safety barriers, being seriously degraded. The NRC Resident has been notified.

• * * RETRACTION ON 10/21/21 AT 1153 EDT FROM DENNIS BRIED TO BRIAN P. SMITH * * *

The condition identified in EN 55457, pursuant to 10 CFR 50.72 (b)(3)(ii)(A) has been evaluated, and has been determined not to be Reactor Coolant System (RCS) pressure boundary leakage. As such, the 8-hour report is being retracted, as it is not an event or condition that results in, 'the condition of the nuclear power plant, including its principal safety barriers, being seriously degraded.' The leakage was subsequently determined to be in a tubing connection downstream of the reactor vessel inner O-ring. Leakage past a seal or gasket is not considered to be pressure boundary leakage, as defined by Technical Specifications. The NRC Resident Inspector has been notified. Notified R2DO (Miller)

EN Revision Imported Date : 3/30/2020 DEGRADED CONDITION On March 26, 2020, while McGuire Unit 2 was shut down for a scheduled refueling outage, the reactor vessel head penetrations were being examined in accordance with the in-service Inspection Program. Ultrasonic examinations identified a relevant indication in the Control Rod Drive Mechanism nozzle number 35 that did not meet the acceptance criteria under ASME, Section XI IWB-3600, 'Analytic Evaluation of Flaws.' Actions to address the relevant indication will be taken in accordance with the applicable codes, standards, and regulations. This event is being reported as an eight-hour non-emergency notification per 10 CFR 50.72(b)(3)(ii)(A). The relevant indication has no impact on the health and safety of the public or station employees. The NRC Resident Inspector has been notified.

• * * RETRACTION ON 3/29/2020 AT 1700 EDT FROM TOM BERNARD TO BRIAN P. SMITH * * *

McGuire is retracting the eight hour non-emergency notification made on March 26, 2020, at 10:45 ET (EN#54614). A subsequent evaluation determined that the suspect indication identified during ultrasonic examination of Control Rod Drive Mechanism nozzle number 35 is not service induced nor representative of primary water stress corrosion cracking (PWSCC). The indication has been classified as "non-relevant" and is not reportable as a degraded condition. The senior NRC Resident Inspection has been notified. Notified R2DO (Miller).

At 1951 (EDT) on October 17, 2019, fretting indications on the reactor coolant system pressure boundary piping (pressurizer spray line) were identified. This condition does not appear to meet original construction code, ANSI B31.1, 1967 Edition thru summer 1971 Addenda. The condition will be resolved prior to plant startup. This event is being reported as an eight-hour non-emergency notification per 10 CFR 50.72(b)(3)(ii)(A). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. This condition will be corrected prior to the plant entering Mode 4.

• * * RETRACTION ON 10/31/19 AT 1450 EDT FROM JIM SCHWER TO BETHANY CECERE * * *

An engineering evaluation has determined that the subject fretting is not considered a flaw, but instead is considered wear. Appendix F of Section III of the ASME Boiler and Pressure Vessel Code was applied and it was determined that the pressurizer spray line piping maintained its required design safety functions in the as-found condition. The wear has been repaired during the current refueling outage in accordance with the original construction code (ANSI B3l.l, 1967 Edition through summer 1971 Addenda) as well as Owner's Requirements. The NRC Resident Inspector has been notified. Notified R1DO (Young).

On November 11, 2018, during ultrasonic data analysis from reactor vessel closure head in-service inspections, signals that display characteristics consistent with primary water stress corrosion cracking in head penetration 33 were identified. No indications of boric acid leakage and no surface indications were detected at this location during bare metal visual inspection.

The plant was in cold shutdown at 0% power and in Mode 6 for a refueling outage at the time of discovery. Repair actions will be completed prior to plant startup from the outage. This condition has no impact to the health and safety of the public. This report is being made in accordance with 10 CFR 50.72(b)(3)(ii)(A) for degradation of a principal safety barrier. The licensee notified the NRC Senior Resident Inspector.