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The following information was provided by the licensee via phone and email: A non-licensed, contract employee supervisor had a confirmed positive for alcohol during a follow-up fitness-for-duty test. The employee's access to the plant has been terminated. The NRC Resident Inspector has been notified.

• * * RETRACTION FROM GERALD WOLF TO DONALD NORWOOD AT 1448 EDT ON 3/16/2022 * * *

The following information was received from the licensee via E-mail: This is a retraction of EN55775. The measured Blood Alcohol Level (BAC) of the individual was below the Fitness-For-Duty program limits, so this event did not constitute a violation of the Fitness-For-Duty program. The NRC Resident Inspector has been notified. Notified R3DO (Hills) and the FFD E-mail group.

On 11/3/17, with the unit operating in Mode 1 at approximately 100 percent power, an issue was identified with the Station Vent Radiation Monitors. The noble gas channels utilize an efficiency factor for isotope Kr-85 instead of the required Xe-133. For the normal range radiation monitors, the efficiency factor is non-conservative, resulting in both monitors being declared inoperable at 1045 hours EDT. As a result, the Normal Control Room Ventilation System was shut down and isolated, and the Control Room Emergency Ventilation System started in accordance with Technical Specification Required Actions at 1122 hours. The inoperability of both Station Vent Normal Range Radiation Monitors represents a condition that at the time of discovery could have prevented the fulfillment of the safety function of a system needed to mitigate the consequences of an accident. The Station Vent Accident Range Monitors also utilize an efficiency factor for Kr-85 instead of Xe-133, but for the Accident Range Monitors the efficiency factor is conservative. Because alternate means exist to determine release rate, which include use of grab samples and field surveys, this degraded capability does not represent a major loss of emergency assessment capability. The NRC Resident Inspector has been notified.

• * * RETRACTION FROM NICK DOWNING TO DONALD NORWOOD AT 0927 EST ON 12/14/2017 * * *

On 11/3/2017, the efficiency factors for the Station Vent Normal and Accident Range Radiation Monitors were revised to the proper setting for the required isotope, the normal range monitors were declared Operable, and the Control Room Normal Ventilation System was returned to service. An evaluation of the issue with the Station Vent Normal Range Radiation Monitors was performed, which determined the Control Room Ventilation isolation setpoint is well below the point at which the dose to the Control Room Operators would exceed General Design Criteria (GDC) limits following a Design Bases Accident. The error introduced from using an incorrect efficiency value did not challenge the margin to the GDC limits; therefore, the Station Vent Normal Range Monitors remained operable, and this issue did not prevent the monitors from fulfilling their safety function to mitigate the consequences of an accident.

The NRC Resident Inspector has been notified. Notified R3DO (Stone).

At 1657 Eastern Daylight Time (EDT) the plant entered Mode 4 (from Mode 5), and subsequently, at 1710 EDT, it was discovered that 480V AC essential busses E1 and F1 were being supplied from the shutdown operations transformers. The essential busses E1 and F1 are required to be aligned to the power operations transformers in Mode 4 for operability in accordance with TS 3.8.9. With both E1 and F1 essential busses aligned to the shutdown operations transformers with the plant in Mode 4, both trains of the essential electrical power distribution system were inoperable, resulting in a loss of safety function. At 1733 EDT both E1 and F1 essential busses were aligned to the power operations transformers as required by TS 3.8.9. This issue is being reported as a loss of safety function of the essential electrical busses. The NRC Resident Inspector has been notified of the event.

• * * RETRACTION AT 1315 EST ON 11/09/2016 FROM ANDY MILLER TO JEFF HERRERA * * *

Engineering reviewed the actual conditions during the approximate 36 minutes the 480V AC essential busses were being supplied from the shutdown operations transformers. Grid voltages were higher than assumed minimum voltages, and electrical loading during Mode 4 conditions were reduced from expected full power operation loading. As a result, Engineering determined that all equipment remained capable of performing its required functions while connected to the shutdown operations transformers. Because the equipment remained capable of satisfying the requirements for Operability, no condition existed that could have prevented the fulfillment of a safety function. Therefore, no loss of safety function existed for the 480V AC essential buses, and the notification made per 10 CFR 50.72(b)(3)(v)(A-D) by the Davis-Besse Nuclear Power Station on 9/16/2016 (EN# 52247) is being retracted. The NRC Resident Inspector has been briefed on the evaluation results and informed of this retraction. Notified the R3DO (Jeffers).

At 1150 hours on 9/15/03 during Reactor Coolant System (RCS) pressure increase to approximately 700 psig, the Core Flood (CF) Tank 1 outlet motor-operated valve (CF1B) opened when the breaker for the valve was closed. Because RCS pressure was not high enough to actuate the pressure switch setpoint of 770 psig to open this valve, it was believed this was an invalid signal, and therefore the valve opening was not reportable under the criteria of 10 CFR50.72 After further review, at 0030 hours on 9/16/03 it was determined the sensed pressure was within the setpoint range of the switch, making this a valid signal to open the valve. The CF Tank pressure at the time (approximately 600 psig) was less than the RCS pressure of approximately 700 psig, therefore no discharge into the RCS occurred, and this event is not reportable per 10 CFR50.72(b)(2)(iv). The CF System is a passive system, but is used in conjunction with other Emergency Core Cooling Systems to mitigate significant events. Therefore, this event involving the opening of the CF Tank discharge valve CF1B is being conservatively reported in accordance with 10 CFR50.72(b(3)(2)(iv)(A) as a valid actuation of a train of the Emergency Core Cooling System. Upon opening of this valve, CF Tank 1 level and pressure were observed lowering with a corresponding rise in the Reactor Coolant Drain Tank, most likely due to leakage past a check valve. CF1B was closed according to procedures and the source breaker for the valve opened. The NRC Resident Inspector was notified by the licensee.

• • • RETRACTION on 11/11/03 at 1643 EST by R. Walleman to MacKinnon ****

The actuation of the interlock for the Core Flood Tank 1 Outlet Isolation Valve did not constitute an actuation of the Core Flood System. The valve opened automatically as designed to ensure the Core Flood System was capable of performing its safety prior to being manually opened by the Operators. As part of the Emergency Core Cooling Systems, the primary function of the Core Flood System is to deliver cooling water to the reactor core in the event of a Loss of Cooling Accident per the Updated Safety Analysis Report. However, plant conditions (namely, Reactor Coolant System pressure lowering below Core Flood Tank pressure) did not exist that would have required the Core Flood System to perform its safety function. Therefore, the automatic opening of this valve does not constitute the actuation of the Emergency Core Cooling System, so this event is not reportable per 10CFR50.72(b)(3)(iv)(A). Therefore, NRC Event Number 40161 is retracted." R3DO (Anne Marie Stone) & NRR EO (Herb Berkow) notified. The NRC Resident Inspector will be informed of this retraction by the licensee.