Event Notification Report for February 03, 2023

AGREEMENT STATE REPORT - STUCK SHUTTER
The following information was provided by the Mississippi Division of Radiological Health via email:

"During routine preventive maintenance on 1/23/2023, Tronox, LLC, discovered a stuck shutter on their Ohmart SHF-1-0, serial number 2641GK, 10mCi Cs-137. The shutter is stuck in its normal operating position.

"Using a Ludlum model 2241-2, serial number 313844 with a Ludlum Model 44-2 detector, the licensee measured 150 microrem/hr at 1 meter from the source and 1.4 millirem/hr at the surface.

"The gauge is mounted on an elevated platform in a process area. The area is not a routinely occupied work area and restrictions have been posted. The stuck shutter appears to be caused by corrosion. The licensee is working on a timeline for the repair.

"Mississippi Event Number: MS-230001"

AUTOMATIC SCRAM DUE TO TURBINE TRIP

The following information was provided by the licensee via fax and telephone:

"Generator trip due to power load unbalance which caused a turbine trip and subsequent reactor scram. Experienced a trip on circulating water pump A.

"NRC Resident Inspector notified."

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

Off-site power available and unaffected. Decay heat removal via main steam line and drains to condenser. Plant is stable in mode 3.

EN Revision Imported Date: 2/3/2023

EN Revision Text: AUTOMATIC REACTOR TRIP DUE AND AUTOMATIC ACTUATION OF AUXILIARY FEEDWATER SYSTEM

The following information was provided by the licensee via email:

"At 0956 CST with Unit 1 in Mode 1 at 100 percent power, the reactor automatically tripped due to a turbine trip. The trip was not complex with all safety related systems responding normally post-trip. During the trip, the non safety related '1A' 4160V bus lost power resulting in the loss of one Reactor Coolant Pump (RCP-1A). Operations responded and stabilized the plant. The '1A' 4160V bus was re-energized at 1031 CST. Decay heat is being removed by steam dumps to the main condenser. Farley Unit 2 is not affected.

"An automatic actuation of [Auxiliary Feedwater] AFW also occurred, which is an expected response from the reactor trip.

"Due to the 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) and an eight-hour report per 10 CFR 50.72(b)(3)(iv)(A) as an event that results in a valid actuation of the Auxiliary Feedwater System.

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

LIMITING CONDITION OF OPERATION NOT MET

The following information was provided by the licensee via email:

"[University of California, Davis McClellan Nuclear Research Center] MNRC received its new 20 year operating license from the NRC on November 21, 2022. As part of the new license, several new conditions in the technical specification were added for consistency with other non-power reactors and to give greater assurances of public safety beyond the previous technical specifications.

"The license condition involved in this event is Technical Specification 3.3 specification 4 concerning the maximum allowable activity of radionuclides in MNRC's primary cooling water with half-lives greater than 24 hours. The specific requirement is that these radionuclide concentrations shall be less than the 10 CFR 20 Appendix B table 3 values for the reactor to be operated. When agreeing to this new technical specification, MNRC staff looked at the historical values for all non-tritium nuclides having half-lives greater than 24 hours. These nuclides are assayed at MNRC via high resolution gamma-ray spectroscopy. For these nuclides MNRC is able to meet the new [limiting condition of operation] LCO limit easily. Separately, MNRC staff evaluated the tritium activity that was provided to MNRC via a 3rd party laboratory. The latest result from the 3rd party laboratory appeared to confirm that MNRC would meet the new tritium limit of 0.01 uCi/ml by having a tritium concentration of approximately 1/40th of this value.

"On January 31, 2023, during the planning for the required surveillance of technical specification 3.3 item 4, it was discovered that the 3rd party laboratory result was incorrect and they mistakenly underreported tritium concentrations by a factor of 100. At approximately 1600 (PST) on the same day, it was verified that MNRC's primary water tritium concentration was approximately 2.5 times the new technical specification limit given in section 3.3 item 4, resulting in not being able to meet an LCO. A more thorough data review shows that historical concentrations of the tritium in MNRC's primary coolant are very constant (except for the misreported data used to evaluation MNRC's ability to meet the new technical specification 3.3 item 4). Therefore, failing to meet this LCO is a condition that has likely existed since the issuing of the new license on November 21, 2022. MNRC was not operating at the time of this discovery and has not resumed reactor operations.

"There has likely been no increase in the amount of tritium in MNRC's primary cooling water nor has any primary cooling water been released from the reactor tank since the new technical specification took effect. There are no safety or security concerns generated as a result of this event.

"The facility license holder (level 1 management), the chair of the MNRC safety committee, MNRC's NRC program manager, assistant program manager, and inspector have been notified of this event. The ultimate resolution of this issue will need to be a license amendment increasing the permissible tritium concentration in the primary cooling water as a condition for reactor operation as it is physically impossible to lower the tritium concentration in order to meet the LCO."