Event Notification Report for December 18, 2020

AGREEMENT STATE REPORT - SHUTTER MALFUNCTION

The following information was received from the Texas Department of State Health Services (the Agency) via email:

"On December 8, 2020, the Agency received an e-mail from the licensee stating that during routine testing the shutters on two nuclear gauges were found stuck in the open position. The gauges are Vega model SH-F1 both containing 20 milliCuries (original activity) cesium-137 sources. The licensee reported there is no risk of radiation exposure to members of the general public or workers at the facility due to the failures. The licensee stated they were working on a plan to repair the gauges and would provide that information once the plan is completed. Additional information will be provided as it is received in accordance with SA-300."

Texas Incident No: I-9815

FITNESS FOR DUTY

A plant employee, after being selected for a random fitness-for-duty test, admitted to use of a controlled substance. The employee's unescorted access to the facility has been placed on hold pending an investigation.

The NRC Resident Inspector has been notified.

AUTOMATIC REACTOR TRIP DUE TO GENERATOR LOCKOUT

"On December 16, 2020 at 0851 EST, with Harris Nuclear Plant Unit 1 in Mode 1 at 80 percent power, an automatic reactor trip occurred due to lockout of the main generator. The trip was not complex, with all systems responding normally post-trip. The initial assessment of this event indicates that there was a ground fault on the 'B' train of the non-safety electrical distribution system that caused the main generator lockout. Steam generator levels are being maintained by normal feedwater through the feedwater regulator bypass valves. Decay heat is being removed by using the condenser steam dump flow path.

"Due to the unplanned Reactor Protection System actuation while critical, this event is being reported as a four hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B).

"This condition does not affect the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified."

All rods inserted into the core during the trip. The electrical grid is stable and all safe shutdown equipment is available for service. No reliefs lifted during the transient.

ACCUMULATOR DISCHARGE VALVES ISOLATED WITH PLANT GREATER THAN 1000 PSIG

"On December 17, 2020 at 1539 EST, with Harris Nuclear Plant Unit 1 preparing for entry into Mode 4, the Reactor Coolant System was pressurized greater than 1000 psig for approximately 15 minutes with all three Cold Leg Injection Accumulator Discharge Valves closed. This event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(D). Both Low Head and High Head Safety Injection Systems were operable at this time.

"This condition does not affect the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified."