Event Notification Report for December 20, 2023

HIGH PRESSURE COOLANT INJECTION SYSTEM INOPERABLE

The following information was provided by the licensee email:

"At 0223 EST, on 12/18/2023, while Unit 2 was at 100 percent power in mode 1, the high pressure coolant injection (HPCI) outboard steam isolation valve closed resulting in the HPCI system being declared inoperable. The cause of the outboard steam isolation valve closing is under investigation. HPCI does not have a redundant system, therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(D). The safety function was restored at 0512, on 12/18/23, and HPCI has been declared operable. Reactor core isolation cooling (RCIC) and low pressure emergency core cooling systems (ECCS) were operable during this time.

"There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified."

60 DAY NOTIFICATION FOR AN INVALID SPECIFIED SYSTEM ACTUATION

The following information was provided by the licensee via email and phone:

"At 2011 EDT on 11/01/23, with Unit 2 in Mode 3 at 0 percent power, Unit 2 received multiple spurious actuations. These actuations consisted of a partial group 1 and a partial group 5 primary containment isolation and a partial secondary containment isolation. The partial Group 1 isolation resulted in the closure of two main steam isolation valves (MSIVs); all other MSIVs were already closed. The partial group 5 isolation auto closed one of the reactor water cleanup (RWCU) isolation valves. The partial secondary containment isolation resulted in the closure of the inboard refueling floor and reactor building secondary containment isolation valves (SCIVs).

"Additionally, at 2238 EDT, Unit 2 again received multiple spurious actuations. These actuations consisted of a partial group 5 primary containment isolation and a partial secondary containment isolation. The partial group 5 isolation auto closed one of the RWCU isolation valves The partial secondary containment isolation resulted in the closure of the inboard refueling floor and reactor building SCIVs.

"And again, at 2354 EDT, Unit 2 received spurious actuations which consisted of a partial secondary containment isolation which resulted in the closure of the inboard refueling floor and reactor building SCIVs.

"The spurious actuations seen on 11/1/23 are triggered at -35 inches reactor water level (RWL) for group 5 and secondary containment isolations and at -101 inches RWL for group 1 isolations. It was determined that a combination of the RWL fluctuating above and below the wide range instrument reference leg tap, the reactor vessel pressure being lowered, and reactor core isolation cooling introducing colder water conditions near the reference leg tap of the wide range instrument caused the spurious actuations. Using multiple RWL indications for each of the instances mentioned above, the actuations were confirmed to be spurious as RWL was being controlled in a band of +55 inches to +85 inches at the time of the actuations.

"This event is being reported in accordance with 10 CFR 50.73(a)(2)(iv)(A) as an event that resulted in an invalid actuation of a partial group 1, a partial group 5, and partial secondary containment logic."

The NRC Resident has been notified.

TECHNICAL SPECIFICATIONS VIOLATION

The following information was provided by the licensee via phone and email:

"At approximately 1100 CST on December 15, 2023, the facility was discovered to be in violation of a Limiting Condition of Operation (LCO) according to Technical Specification 3.3.2.2, which requires that the static pressure measurement in the confinement exhaust system measure -0.1 inches of water or less during operation. It was discovered that this plant variable was not tied to the PANALARM trip for 'Building Pressure', nor was the sensor output value available in the control room to be checked by operators. The PANALARM trip for 'Building Pressure' was set to a different variable not related to the LCO required value. This condition has existed since 2006.

"The reactor was not in operation at the time of the discovery, and the situation creating this LCO violation is being corrected prior to the next reactor startup."

The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:

The issue was discovered by the vendor when a controller board was being replaced after damage from a power outage.

INITIAL PART 21 REPORT - DEFICIENT FUEL INJECTORS

The following is a synopsis of information was provided by the licensee via phone and email:

Pursuant to 10 CFR 21.21(d)(3)(i), Paragon provided initial notification of a defect associated with the auxiliary feedwater pump diesel engine fuel injectors supplied to Constellation. The injectors were provided to Paragon for refurbishment. Constellation provided Paragon with root cause report # 4703982 on November 12, 2023. The associated failure analysis report documented potential defects with some fuel injectors supplied to Braidwood. These reported deficiencies allowed excessive fuel oil leakage which resulted in diesel lubricating oil system contamination above specified limits. Paragon concluded their evaluation on December 18, 2023, which determined that this condition, if left uncorrected, could contribute to a substantial safety hazard and is reportable in accordance with 10 CFR Part 21.

The extent of condition is limited to the Constellation Braidwood and Byron plants.

Paragon has entered this condition in their corrective action program. Affected injectors at Braidwood have been removed from service and returned to Paragon. Paragon is coordinating with Byron on recommended actions and will follow up with a final notification on or before 1/17/2024.