Event Notification Report for November 17, 2021

EN Revision Imported Date: 11/17/2021

EN Revision Text: MANUAL REACTOR TRIP DUE TO MAIN TRANSFORMER FAULT

"At 1728 EST on 11/15/2021, with Unit 1 in Mode 1 at 47 percent power, the reactor was manually tripped due to a main transformer fault. The trip was not complex, with all systems responding normally post-trip. Operations responded and stabilized the plant. Decay heat is being removed by the emergency feedwater system through the main condenser.

"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).

"Additionally, due to the valid actuation of the emergency feedwater system, this event is being reported as a non-emergency notification per 10 CFR 50.72(b)(3)(iv)(A).

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

* * * UPDATE ON 11/16/21 AT 1649 EST FROM BRUCE BENNETT TO KERBY SCALES * * *

"At approximately 0900 [EST] on 11/16/2021, it was identified that mineral oil from the faulted main transformer had surpassed the capability of the oil containment system and discharged into Lake Monticello. It is estimated that less than 50 gallons of mineral oil entered the Lake. The oil is contained with booms and cleanup is ongoing. The EPA National Response Center and the South Carolina Department of Health and Environmental Control have been notified. This is considered a news release or notification to other government agencies; therefore, this event is reportable under 10 CFR 50.72(b)(2)(xi).

"The NRC Senior Resident Inspector has been notified."

Notified R2DO (Miller).

ABNORMAL OCCURRENCE

"University Of Missouri Research Reactor (MURR) Technical Specification (TS) 6.6.c(1) requires notification to the NRC Operations Center that an Abnormal Occurrence, as defined by MURR TS 1.1, has occurred. MURR was not in compliance with one (1) of the TS Limiting Conditions of Operations. TS 3.2.g states, 'The reactor safety system and the number (N) of associated instrument channels necessary to provide the following scrams shall be operable whenever the reactor is in operation.' Specifically, the reactor safety scram function that occurs when the differential pressure across the reactor pool reflector (PT-917) instrument channel decreases below 2.52 psi minimum in Mode 1 operation was not operable as required by TS 3.2.g.10.

"On 11/15/21 while the reactor was shut down, Control Room operators shut down the pool coolant system and noticed that the `Reflector Hi-Low Diff Pressure Scram' annunciator alarm did not initiate as pool coolant flow rate decreased to zero. The Control Room operators contacted reactor management, and an investigation was initiated to prove whether or not the safety scram function from the PT-917 instrument channel actuated correctly. Further testing revealed the safety scram signal from the PT-917 instrument channel did not occur due to a failed alarm-meter unit. The alarm-meter unit was replaced with an exact spare, the PT-917 instrument channel was calibrated, and the reactor safety scram functions of the PT-917 instrument channel were retested satisfactorily.

"In accordance with TS 6.6.c(4), the Reactor Facility Director was briefed and gave permission to restart the reactor prior to the reactor returning to operation later on 11/15/21. Currently, MURR is operating at 10 MW. A detailed event report will follow within 14 days as required by MURR TS 6.6.c(3)."

The NRC Project manager was notified.

AGREEMENT STATE REPORT - STUCK SHUTTER

The following was received from the state of Illinois (the Agency) via email:

"The Agency was notified by British Petroleum [BP] (registered as a general licensee under the name CHICAP Pipe Line Company (9152422)), that they had discovered a stuck shutter on a generally licensed fixed gauge at their Lemont, IL location. The shutter, which is normally open, has apparently been broken for many years and was only discovered during removal last week. No personnel exposures resulted and the gauge has been secured pending disposal.

"A specifically licensed service provider was removing a generally licensed fixed gauge on 11/10/21 for planned disposal through a waste broker when it was discovered to have an inoperable shutter. The gauge was a Ronan Engineering Company model SA-1, containing 50 milliCi of Cs-137 (s/n 8333GG). While the shutter was reportedly routinely tested, the arm that moves the shutter was severely corroded. It was only during removal that the registrant discovered the shutter itself was broken. The gauge has been in service for 24 years and was installed at a 12' height with the beam projecting into the process equipment. As the shutter remains in the open position and personnel are not in the beam path, personnel exposure is not a concern. No reported exposures during removal. The gauge has been double locked with the beam facing down into the concrete floor. The shutter is being repaired so it may be properly transported and disposed of through Bionomics (waste broker). A written report detailing remedial action is required within 30 days under 32 Ill. Adm. Code 330.220(a)(3)(E).

"This incident is reportable under 32 Ill. Adm. Code 340.1220. At this time, it does not appear a response to the site by Agency staff will be required. BP's consultant indicated that the gauge manufacturer reports 3-4 of these gauges per year are returned. The issue is reportedly a seal that leaks and gives rise to corrosion - despite being used within the environmental conditions specified in the SSDR [Seal Source Device Registry]. This information is anecdotal but included for NRC's evaluation and trending analysis. This matter will remain open until confirmation of shipping for disposal is received."

Illinois Item Number: IL210037