Event Notification Report for May 25, 2022

AGREEMENT STATE REPORT - DISCOVERED FIXED GAUGE

The following information was received from the Oklahoma Department of Environmental Quality (DEQ) via email:

"On 5/17/2022, the state of Arkansas notified Oklahoma DEQ's Radiation Management Section that a DOT [(Department of Transportation)] Special Permit 10656 had been issued for a trailer that originated in Sallisaw, Oklahoma. The load was surveyed at the scrap metal facility in Arkansas and sent back to Oklahoma. It arrived back to Sallisaw today and was surveyed by the owner of the salvage yard. The owner of the salvage yard found a Thermo Measure Tech Model 5201 fixed gauge containing 50 mCi of Cs-137, serial number R4473. The source housing appears to be intact. When the gauge was removed from the trailer no additional radiation was measured on the trailer. The facility owner was instructed to isolate and secure the gauge. The owner stated that he would place it in a drum and lock it in a concrete shed."

DOT Approval Number: AR-OK-22-007

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)."

EN Revision Imported Date: 5/25/2022

EN Revision Text: MANUAL REACTOR TRIP FOLLOWING MANUAL TURBINE TRIP FROM HIGH VIBRATIONS ON MAIN TURBINE

The following information was provided by the licensee via email:

"On May 24, 2022, at 0414 EDT, while rolling the Unit 1 main turbine during the Unit 1 Cycle 31 refueling outage, the Unit 1 main turbine experienced high vibrations and the main turbine was manually tripped with reactor power at 12 percent. Main turbine vibrations persisted and the reactor was manually tripped, Main Steam Stop Valves were closed, and main condenser vacuum was broken.

"This notification is being made in accordance with 10 CFR 50.72(b)(2)(iv)(B), Reactor Protection System (RPS) actuation as a four (4) hour report, and under 10 CFR 50.72(b)(3)(iv)(A), specified system actuation of the Auxiliary Feedwater System, as an eight (8) hour report. The DC Cook Resident NRC Inspector has been notified.

"Unit 1 is being supplied by offsite power. All control rods fully inserted. Both Motor Driven Auxiliary Feedwater Pumps started properly. Decay heat is being removed via Steam Generator Power Operated Relief Valves. Preliminary evaluation indicates all plant systems functioned normally following the Reactor Trip. DC Cook Unit 1 remains stable in Mode 3 while conducting the Post Trip Review. No radioactive release is in progress as a result of this event."

EN Revision Imported Date: 5/25/2022

EN Revision Text: PROCEDURAL NONCOMPLIANCE WITH ADMINISTRATIVE ITEMS RELIED ON FOR SAFETY (IROFS)

The following additional information was obtained from the licensee by phone and email:

"Administrative IROFS WT-165 and WT-166 require independent operators to sample and verify the V-1170 uranium concentration is below an administrative limit prior to discharge to the V-1160 tank. These IROFS were correctly performed on May 18, 2022, for both the V-1170A and V-1170B tanks. In between the 18th and the 23rd, the warm caustic filter was water washed with the process solution sent to the V-1170 tanks.

"At 0422 EDT on May 23, 2022, the contents of V-1170A and V-1170B tanks were pumped to the T-1160B tank without the tank uranium concentration being updated following the warm caustic filter wash.

"At 0925 EDT on May 23, 2022, an evaluation into the reportability of the event was initiated when a Uranium Recovery and Recycling Services (URRS) team manager contacted Criticality Engineering to report the transfer without the test results required by procedure. After reviewing updated tank test results, performing calculations to determine risk, and discussing actions taken by the operators, IROFS WT-165 and WT-166 were considered failed and IROFS WT-171, WT-172, WT-175 and WT-176 were considered degraded.

"Per CSE-15C-S1-G3, the remaining safety margin was 1.000E-2, which was below the required 1.000E-4.

"The result is reportable per 10 CFR Part 70 Appendix A (b)(2), 'Loss or degradation of items relied on for safety that results in failure to meet the performance requirements of 10 CFR 70.61.'

"Following the event, the contents of V-1170A and T-1160B were tested and historical tank level indication data was reviewed with results well within the IROFS limits. There was no safety impact as a result of the failed IROFS."

DEGRADATION TO A FUEL ELEMENT CLADDING

The following information was provided by the University Of Utah Training Reactor (UUTR) via email:

"This is a written report to NRC regarding minor damage to a fuel element identified during routine fuel inspection operations, filed per UUTR Technical Specification para 6.7.2, 'Special Reports' noting degradation in a reactor fuel element cladding. On Tuesday, May 24 2022, at 1115 [MDT], during a routine UUTR bi-annual fuel inspection, one stainless steel U-235 TRIGA fuel element removed from core position D-14, element number 4138E, was noted to have low-level surface pitting and severe discoloration at several locations along the element length. When this fuel element was moved toward the inspection apparatus, at one of the pitted locations on the surface of the fuel element, a small stream of clear bubbles began to evolve. This was captured on high resolution video; the bubbles were presumed to be fission gas. Reinspection of this same fuel element one hour later with high resolution video showed no evolution of gas bubbles, and the element remained intact. Radiation levels throughout the facility remained constant and consistent with background levels.

"Response to this Event: After initial observation of the pitting and bubble evolution, the fuel element number 4138E was placed in a fuel element storage rack; local radiation levels remained at measured background levels at all times from multiple instruments. On the facility continuous air monitor, no noted deviations from background levels were observed over the entire period of concern. Radiation readings throughout the duration of this observation remained at background levels, and no significant issues or safety concerns were noted; the reactor and facility remain secure, and fuel inspection operations will continue over the next week.

"Follow-up Actions: UUTR reactor personnel will permanently remove fuel element number 4138E from service, and continue to monitor for any instance of elevated radiation levels from the reactor pool. All levels remain stable at background levels."

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

The Non-Power Reactor Project Manager will be notified and the Utah State Radiation Safety Officer was notified.

The estimated time for restart is one week.