ML25262A173
| ML25262A173 | |
| Person / Time | |
|---|---|
| Site: | Kansas State University |
| Issue date: | 09/19/2025 |
| From: | Cebula A Kansas State University |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| Download: ML25262A173 (1) | |
Text
US Nuclear Regulatory Commission Washington, DC 20555-0001 19 September 2025 KANSAS STATE I TRIGA Mk II Nuclear u N I v E R s I T y Reactor Laboratory
Subject:
KSU TRI GA Mark II Reactor Facility Reportable Occurrence - Unreviewed Facility Change To Whom It May Concern, The following written report is submitted to document a reportable occurrence at the Kansas State University TRIGA Mark II nuclear reactor, License R-88. The NRC Event Notification number pertaining to this occurrence is 57930.
Background
As described in the Safety Analysis report, normal electrical power from control room breaker boxes is provided to instrumentation and control systems in the control room and reactor bay.
Outlets in the control room provide power for the reactor control system and area radiation monitoring system with the reactor control system protected by a low voltage relay. An interruption of electrical power to the reactor control system will de-energize the control rod drives, causing the control rods to fall by gravity into the core placing the reactor in a subcritical configuration. Manual resetting of the low voltage relay following normal power loss is required to restore powerto the reactor control system..
Except for the independent area radiation monitor in the control room, area radiation monitors are connected to an uninterruptable power supply (UPS) battery backup in the control room. In addition to other devices and experiments, outlets in the reactor bay provide normal electrical power to the continuous air monitor (CAM) and exhaust plenum monitor (EPM). As part of a previously reviewed facility change using the 1 0CFR50.59 process, the CAM and EPM systems in the reactor bay have UPS battery backup supply.
Reportable Occurrence Description As part of planned upgrades to the control room, a backup electrical panel and three dedicated outlets were to be installed to provide emergency power to supplement the battery backup for the area radiation monitor system rack in the control room and the CAM and EPM airborne radiation monitoring systems in the reactor bay. On 10 September 2025, existing electrical circuits in the control room breaker panel were relocated to a backup electrical subpanel before a change review using the 1 0CFR50.59 process was completed. The backup subpanel is connected to the automatic transfer switch and backup generator system. A senior reactor operator (SRO) was present while the changes were made by an external contractor. The relocated circuits supply power to the control panel, control room computers, area radiation monitor rack in the control room, CAM in the bay, EPM in the bay, and outlets at the 22' level in the reactor bay. Following the electric power change, the reactor was operated for training and proficiency purposes on 11
September 2025, 12 September 2025, and the morning of 15 September 2025 before the reportable occurrence was identified.
On 15 September 2025, after returning from attending an out-of-town conference, the Reactor Manager was informed by the SRO of the changes to the electrical power systems in the control room and reactor bay. Upon inquiry, the SRO indicated no review of the change had been performed under the 1 0CFR50.59 process. The reactor manager notified the NRC of the reportable occurrence due to unreviewed changes to the facility on 15 September 2025.
Even though the console was connected to emergency backup power, it was not connected to an UPS so the low voltage breaker would have removed power from the console and control rod drives iri the event of normal power interruption. The event did not result in property damage, personal injury or exposure.
Summary of Findings The following factors have been identified as contributing to the event:
- 1. Lack of training, review, and use of Management Order SOM5 Configuration Management: Equipment Changes for changes to the facility.
- 2. Ignorance on the part of an SRO regarding the management order covering the 10 CFR 50.59 process.
- 3. Inconsistency in use of procedures in hand or review of procedures before conducting reactor activities that are performed infrequently.
Immediate Corrective Action and Efficacy The following actions were taken in response to the reportable occurrence:
- 1. Upon identifying the reportable occurrence, the Reactor Manager notified the Reactor Supervisor that operations were suspended effective immediately.
- 2. Communication ofreportable occurrence:
- a. An entry in the operations logbook was made declaring suspension of operations.
- b. NRC, Reactor Safeguards Committee, and reactor staff notified of reportable occurrenc.e by email
- 3. Reactor control console reconfigured to normal electrical power supply.
The immediate corrective actions were effective at preventing further operations, communicating the facility status, and restoring the reactor control system to normal electrical power.
Additional Corrective Actions The following additional corrective actions will be taken to prevent recurrence of this reportable occurrence:
- 1. Prior to resuming reactor operations, Reactor Safeguards Committee will review and approve a revised management order implementing the 1 0CFR50.59 process for equipment changes. The management order will be revised to align with requirements in sections 6.2 and 6.3 of Technical Specifications and NEI 21-06. Estimated completion date: 9/22/2025
- 2. Prior to resuming reactor operations, the electrical power supply will be restored to the previous configuration. Estimated completion date: 9/24/2025
- 3. All licensed operators will be notified of the revised management order implementing the 10 CFR 50.59 process at the facility. Estimated completion date: 9/22/2025
- 4. All reactor operators and staff will be briefed on the occurrence review and follow up actions including training on the revised management order. Estimated completion date:
9/26/2025 A copy of this report will be provided to the Reactor Safeguards Committee for review.
Resumption of operations will only occur following Reactor Safeguards Committee approval.
- Regards, Alan T. Cebula, PhD Nuclear Reactor Facility Manager Alan Levin Department ofMechanicaland Nuclear Engineering Kansas State University 112 Ward Hall Manhattan, KS 66506