ML24221A288

Follow-Up Report on EN-57239, Deviation from 10 CFR 50.54(k) and Missouri S&T Reactor (R-79) Technical Specification 6.1.3.1.a)

ML24221A288
Person / Time
Site:	University of Missouri-Rolla
Issue date:	08/08/2024
From:	Graham J, Taber E Missouri Univ of Science & Technology
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
Download: ML24221A288 (1)

Text

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• 1 1 MISSOURI Nuclear Reactor Facility S&f 250 West 13 th St, Rolla, MO 65409 -045 0 (573) 341-4236 I reactor @mst.edu I reactor.mst.edu

August 8, 2024

ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001

SUBJECT:

FOLLOW-UP REPORT ON EN-57239, DEVIATION FROM 10 CFR 50.54(k)

AND MISSOURI S&T REACTOR (R-79) TECHNICAL SPECIFICATION 6.1.3.1.a)

Dear Sirs:

The Missouri University of Science and Technology Reactor ("MSTR" with License R-79, Docket No. 50-123) is hereby submitting a written report as a follow-up to our July 24, 2024 phone and email report. Both reports (this written report and the phone/email report) are in regard to the observed deviation from 10 CFR 50.54(k) and MSTR Technical Specification (TS) 6.1.3.1.a) identified as EN-57239. The attached document details the event, surrounding circumstances and root causes, as well as efforts taken and planned to prevent recurrence.

If you have any questions regarding this report, please contact either me, at 573 - 341-4291; or Dr. Joseph Graham, Reactor Director, at 573-341-7759.

Sincerely,

Ethan Taber oseph Graham, PhD Reactor Manager, MSTR Reactor Director, MSTR

Enclosure

cc: Radiation Safety Committee (S&T)

Dr. Joseph Newkirk, Chair of NERS (S&T)

Dr. Ayodeji Alajo, Deputy Reactor Director MSTR (S&T)

Ms. Paulette Torres, Project Manager (NRC)

Mr. Juan Arellano, Facility Inspector (NRC)

1 I 1 MSTR Licensee Event Report 24-01

On July 24, 2024, at 14:00 CT, the Missouri University of Science and Technology Reactor (MSTR) conducted a planned shutdown from 40 kW in support of a thermal power calibration. At approximately 14:10 CT, the control room reactor operator (RO) left the control room and proceeded to the reactor bay to perform additional data collection in support of the thermal power calibration activity. At approximately 15:10 CT, the Radiation Safety Officer (RSO) passed by the control room and observed that the magnet key remained in the control console. The RO was promptly notified and secured the key. The RO notified the Reactor Manager and Senior Reactor Operator (SRO) on Duty by approximately 15:30 CT, who then discussed the issue with the facility director.

For approximately one hour, the MSTR did not meet the requirements of 10 CFR 50.54(k) and MSTR Technical Specification (TS) 6.1.3.1)a). These requirements specify that An operator or senior operator licensed pursuant to [10 CFR 55] shall be present at the controls at all times during the operation of this facility, and 1. The minimum staffing when the reactor is not secured shall be: a) A certified reactor operator in the control, respectively.

During this time, no unauthorized personnel approached or altered the control console, as supported by the presence and tracking of personnel in the reactor bay and the remainder of the reactor facility.

At no point was the health and safety of the public or MSTR in doubt. The Reactor Director authorized the restart of operations as of the morning of July 25, 2024.

=

Background===

The MSTR performs a thermal power calibration to align and check nuclear instrumentation (NI) channel response with thermal output of the reactor core. This process measures thermal expansion of pool water, with correlations developed by the facility to heat input (i.e., integrated reactor power). The measurement is performed over three phases to track initial evaporation, expansion while at power, and final evaporation. Pool water expansion is measured via an arrangement of floats and precision dial gauges, with data collection performed by facility staff on sub-15-minute intervals.

The magnet keyswitch in the reactor console and the corresponding key prevent energizing the magnets and withdrawing the control rods. Other than the presence of the key, the only indications that the key is installed is the overhead Reactor On sign and small magnet power supply indicators or the illuminated red Scram Reset switch if magnets are not energized.

Root-Cause Analysis

Two factors have been determined to root causes of this event:

1. Innocuous appearance of the magnet key and/or keyswitch.

Minimal visual indicators are available to the operator to remind them of the presence/installation of the magnet key. The key is small, and both the key and supporting console are of standard industrial colors.

2. Task saturation or inattentiveness of operator.

The operator was tasked with both operating the reactor and then assisting with the data collection for the calibration. Coupled with other environmental factors (other personnel and activities ongoing at the facility), the operator may have been distracted after performing more direct shutdown actions. Given the operators normal, high level of performance, core or systemic training issues are not suspected.

Corrective Actions

As required by MSTR TS 6.6.2, the reactor oversight Radiation Safety Committee will review this event at its next meeting (before end of Q3 2024).

This event and the corrective actions described herein have been added to the MSTR Corrective Action Program (CAP) as CAP-2024-001.

While not considered a root cause, modifications are under consideration that would reduce the staff workload during and improve reliability of the thermal power calibration. These modifications include a high precision ultrasonic distance sensor for pool height measurements (i.e., to replace the manual reading of dial gauges) connected to a digital data acquisition system. These modifications are expected to be implemented by Q2 2025.

Additionally, the following targeted corrective actions have been performed or planned by the facility to address the root-causes and prevent recurrence. These actions include an Estimated Time to Completion/Implementation (ETC). The NRC will be notified as soon as possible if the ETC implementation timelines or actions are determined to be unworkable.

1. Innocuous appearance of the magnet key and/or keyswitch.

Additional visual indication for the key installed into the console will be implemented.

The final implementation has not been decided, but considerations include a streamer on the keyring or console lighting used to alert the operator when the key is installed but the reactor is in a shutdown state. (ETC for plan 8/31/2024, ETC for implementation 10/31/2024)

2. Task saturation or inattentiveness of operator.

The active operations staff members (i.e., those not presently on leave) were briefed on the incident as of July 25, 2024. Personnel returning from summer leave will be briefed before conducting licensed duties. Future requalification efforts will focus on the event and workload management and vigilance in operations (including reduction or elimination of distractive elements), with requalification lectures and on-the-job training. (Requalification lecture, ETC Q3 2024; on-the-job training, ETC Q4 2024)