Event Notification Report for November 23, 2022

60-DAY OPTIONAL TELEPHONIC NOTIFICATION OF INVALID ACTUATION OF CONTAINMENT VENTILATION ISOLATION VALVES

The following information was provided by the licensee via email:

"This 60-day telephone notification is being submitted in accordance with paragraphs 10 CFR 50.73(a)(1) and 50.73(a)(2)(iv)(A) to report an invalid Containment Ventilation Isolation (CVI) actuation at Watts Bar Nuclear Plant (WBN) Unit 1.

"On November 24, 2022, at 1621 Eastern Standard Time (EST), the Train B CVI actuated due to an invalid high radiation signal from 1-RM-90-131, Containment Purge Air Exhaust Monitor. Upon investigation, the high radiation signal was caused by a failed power supply. Corrective action included replacing the power supply, 1-RM-90-131 ratemeter, and restoring the system to service.

"Prior to and following the invalid high radiation alarm, all radiation monitors except 1-RM-90-131 were stable at their normal values; therefore, the CVI was invalid. Control room operators performed appropriate checks and confirmed that all required automatic actuations occurred as designed. This event has been entered into the corrective action program as Condition Report 1819098.

"The NRC Resident Inspector was notified."

AGREEMENT STATE - STUCK SHUTTER

The following report was received via email from the Texas Department of State Health Services [the Agency]:

"On November 28, 2022, the licensee notified the Agency that it had discovered that the shutter on one of its Ohmart-Vega SH-F1A gauges had been stuck in the closed position since November 23, 2022. The gauge had been closed and locked out on November 22nd for work on the vessel. On November 23rd the gauge was placed back into service. Over the holiday weekend the unit operations had continued to get high readings which would indicate a buildup in the system or a closed shutter. On November 28th the gauge was checked. The licensee's radiation safety officer found the two bolts on the shutter handle were sheared and the shutter was in the fully closed position. No exposures have resulted from this event. An investigation is ongoing. Source: Cesium-137, 5 millicuries, SN: OV-0050 (this SN serves also as the gauge source holder SN). More information will be provided as it is obtained in accordance with SA-300."

Texas Incident Number: I-9966

AGREEMENT STATE REPORT - LOST THEN RECOVERED MOISTURE DENSITY GAUGE

The following information was provided by the California Department of Public Health - Radiation Health Branch (RHB) via email:

"On Wednesday night, November 24, 2022, Arrow Infrastructure Solutions Inc. [doing business as] dba Arrow Engineering [Radiation Safety Officer] RSO [redacted] reported to [California Office of Emergency Services] Cal OES the loss or possible theft of a CPN moisture density gauge, MC-1DR-P (MD70803845) containing sealed sources of Cs-137 (10 mCi) and Am-241:Be (50 mCi), Cal OES Control :22-6906. The loss or possible theft was noticed by the authorized user [AU] at a gas station in Mojave, CA as the user was returning from a jobsite. The AU noticed the truck tailgate down and the CPN gauge missing as they were leaving the gas station after a restroom break, the gauge possibly fell out of the truck on Highway 58 in between Tehachapi and Mojave. The AU retraced their route on the Highway but had not located the gauge so far, they will search again on 11/24/22 during the daylight. The licensee will gather additional information for the follow up investigation and provide additional information to the department as it becomes available.

"UPDATE: The FBI notified RHB Management that the gauge had been found by a member of the public and turned into the Kern County Law Enforcement Agency. The RSO was notified and provided with contact information so the gauge could be retrieved. The RSO was instructed to do a wipe/leak test, get it analyzed quickly, and secure the gauge in storage until a negative result was returned. If a leak is detected, they will coordinate with a service company for repair or disposal. RHB Brea staff will continue with the investigation."

California 5010 Number: 112322

UNINTENTIONAL HIGH-LEVEL SCRAM

The following information was provided by the licensee via email:

"[An] iodized table salt [sample] was inserted to centerline at 1222 (MST) to be irradiated at 4.0 watts. At 1227 the reactor was established as critical at 4.0 watts. The iodized table salt was irradiated until 1320. At 1320 the senior reactor operator communicated to a licensed operator that the salt would be removed. The senior reactor operator pulled the salt out with the power level at 4 watts. The reactor then entered a positive period and jumped to 6.0 watts, resulting in an unintentional high-level scram. The senior reactor operator called the chief supervisor and alerted him immediately of the event who then advised to create a report of the event. The chief supervisor then advised that in the future, better communication is necessary to account for the reactivity differences between an inserted sample and the inserted fuel rods. This event will be added to 'Lessons Learned' for future trainees."

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

The licensee notified the NRR Project Manager (Helvenston).
All reactor systems responded as designed.