Event Notification Report for May 24, 2022

DIESEL FUEL SPILL

The following information was provided by the licensee via email:

"At 0838 [MDT] on May 21, 2022, the diesel fuel day tank level transmitter for the B Central Utility Building (CUB) Standby Diesel Generator failed low. The failed level transmitter signaled the automatic start of the fuel oil transfer pump. When the transfer pump started, it pumped off-highway diesel fuel from the 8000 gallon bulk storage tank, located on the south side of the CUB, to the 150 gallon day tank which was already at its normal operating level of 70-90 percent. Since the level instrument had failed low, the transfer pump continued to run. Level in the day tank continued to rise and diesel fuel spilled from the day tank vent, located above and to the side of the CUB roof. The transfer pump continued to run for 23 minutes until an operator shut down the pump. This stopped the release. An estimated maximum of 240 gallons of diesel fuel was spilled. Most of the diesel fuel landed on the ground outside of the CUB in an area covered by gravel. There were no injured personnel and no radiation exposure as a result of this event.

"The plant is in a safe, stable condition. The B CUB Standby Diesel Generator does not perform a safety function. The transfer pump has been placed out of service. The area is currently being cleaned of diesel fuel. This event has been entered in Urenco USA's corrective action program as EV151632.

"This event was reported to the New Mexico Environment Department at 0643 MDT on May 22, 2022 and is being reported concurrently to the NRC."

EN Revision Imported Date: 5/24/2022

EN Revision Text: SECONDARY CONTAINMENT PRESSURE EXCEEDED TECHNICAL SPECIFICATION REQUIREMENT

The following information was provided by the licensee via email:

"On May 23, 2022, at 0455 CST, Cooper Nuclear Station experienced a spike in Secondary Containment differential pressure which exceeded the Technical Specifications Surveillance Requirements 3.6.4.1.1 limit of -0.25 inches of water gauge. Secondary Containment differential pressure restored to Technical Specification limits within two minutes and further investigation is ongoing. This unplanned Secondary Containment inoperability constitutes a condition reportable under 10CFR50.72(b)(3)(v)(C) and (D).

"The NRC Senior Resident Inspector has been informed."

BOTH TRAINS OF CONTROL ROOM AREA VENTILATION AIR CONDITIONING SYSTEM INOPERABLE

The following information was provided by the licensee via fax:

"At 1256 CST on 05/23/2022, it was discovered both trains of Control Room Area Ventilation Air Conditioning Systems were simultaneously INOPERABLE. Due to this INOPERABILITY, the system was in a condition that could have prevented the fulfillment of a safety function; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v).

"There was no impact on the health and safety of the public or plant personnel.

"The NRC Resident Inspector has been notified."

AUTOMATIC REACTOR SCRAM
The following information was provided by the licensee via email:

"At 1716 hours EDT on May 23, 2022, Susquehanna Steam Electric Station Unit 1 reactor automatically scrammed.

"Unit 1 reactor was being operated at approximately 100 percent [Rated Thermal Power] RTP. The Control Room received indication that both divisions of [Reactor Protection System] RPS actuated from [Reactor Pressure Vessel] RPV high pressure signals and all control rods fully inserted. The Main Turbine bypass valves opened automatically to control reactor pressure. Reactor water level lowered to -42 inches causing Level 3 and Level 2 isolations. [High Pressure Coolant Injection] HPCI [Emergency Core Cooling System] ECCS actuation occurred as designed at -38 inches and injected to the Reactor Vessel. No other ECCS system actuations occurred. [Reactor Core Isolation Cooling] RCIC automatically initiated as designed at -30 inches. The Operations crew subsequently maintained reactor water level at the normal operating band using Feedwater pumps.

"The reactor is currently stable in Mode 3. An investigation is in progress into the cause of the Automatic SCRAM.

"The NRC Senior Resident Inspector was notified. A voluntary notification to [Pennsylvania Emergency Management Agency] PEMA will be made.

"This event requires a 4 hour ENS notification in accordance with 10 CFR 50.72(b)(2)(iv)(A) & 10 CFR 50.72(b)(2)(iv)(B) and an 8 hour ENS notification in accordance with 10 CFR 50.72(b)(3)(iv)(A)."