ML25069A424
| ML25069A424 | |
| Person / Time | |
|---|---|
| Site: | Armed Forces Radiobiology Research Institute |
| Issue date: | 03/10/2025 |
| From: | Smolinski A US Dept of Defense, Armed Forces Radiobiology Research Institute |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML25069A422 | List: |
| References | |
| Download: ML25069A424 (1) | |
Text
Annual Operating Report - 2024 TRIGA Mark-F To satisfy the requirements of:
U.S. Nuclear Regulatory Commission License No. R-84, Docket No. 50-170 Technical Specification 6.6.a.
Prepared by:
Mr. Andrew Smolinski Reactor Facility Director, AFRRI Submitted by:
Gerald F. Burke CAPT, MSC, USN Institute Director, AFRRI
AFRRI 2024 Annual Report
Page 2 of 17
Table of Contents
- 1. Introduction
- 2.
General Information
- a. Key reactor personnel and staffing changes
- b. Reactor and Radiation Facilities Safety Subcommittee (RRFSS) composition
- 3. Facility Operations Summary (T.S.6.6.a.1)
- a. Facility Design Changes (1) License Amendment Request (2) Facility Modifications
- b. Performance Characteristics
- c. Operational and Administrative Procedures
- d. Results of Surveillance Tests and Inspections
- 4. Core Burnup - Characteristics (T.S.6.6.a.2)
- a. Energy Generated by the Reactor Core
- b. Number of Pulses $2.00 or Larger
- 5. Unscheduled Shutdowns (T.S.6.6.a.3)
- a. Unscheduled Shutdowns
- b. Related Corrective Actions to Ensure Safe Operations
- 6. Safety-Significant Maintenance (T.S.6.6.a.4)
- a. Corrective Maintenance
- b. Preventive Maintenance
- 7. Changes affecting the Safety Analysis Report (SAR) (T.S.6.6.a.5 and T.S.6.6.a.6)
(Made pursuant to 10 CFR 50.59 and summaries of 50.59 Safety Evaluations
- a. Changes that affect the description in the SAR
- b. Procedure changes that affect the description in the SAR
- c. New experiments or tests not encompassed in the SAR
- 8. Radioactive Effluents (T.S.6.6.a.7)
- a. Liquid Waste Summary
- b. Gaseous Waste Summary
- c. Solid Waste Summary
- 9. Environmental Radiological Surveys (T.S.6.6.a.8)
- 10. Exposures Greater Than 25% of 10 CFR 20 Limits (T.S.6.6.a.9)
- 11. Conclusion
AFRRI 2024 Annual Report
Page 3 of 17
- 1. Introduction
The TRIGA Mark-F reactor at AFRRI was available for normal operations for the duration of 2024. No additional operating licenses were received or removed: there are a total of five SRO-licensed staff members currently at AFRRI. All surveillance and maintenance activities were completed and within periodicity, and the pace of routine experiments has doubled compared to 2023.
There were three reactor modifications approved under 50.59 during the year and no License Amendment Requests (LAR) submitted. There were nine unscheduled shutdowns during 2023, all due to known causes. All safety systems performed as designed.
The 2024 annual audit required by the reactor technical specifications was conducted from 14 JAN 2025 to 17 JAN 2025 by Mr. Jonathan Wallick from the US Geological Services TRIGA Reactor (GSTR). The audit report indicated no technical specification violations and no major discrepancies in reactor operations, maintenance, or documentation. The audit identified some minor documentation findings, highlighted known degradations in facility equipment that are being worked through by facility staff, and provided suggested changes and improvements.
Details of the audit are provided in Section 3.d.
An NRC inspection of reactor facility operations was conducted by Mr. Andrew Waugh from 15 JUL 2024 to 18 JUL 2024, which included observation of reactor and prep area operations.
The inspection resulted in no new violations or Inspection Follow-up Items (IFI).
The triennial NRC security inspection of the reactor facility was conducted by Mr. Juan Arellano, and Mr. Jared Nadel from 15 JUL 2024 to 18 JUL 2024. The inspection resulted in no significant security concerns or findings of non-compliance There was one change to the Reactor and Radiation Facilities Safety Subcommittee (RRFSS) with the retirement of one of the external members, and reassignment of roles for two others.
The remainder of this report is written in the format designated in the Technical Specifications for the TRIGA Mark-F reactor at AFRRI. Items not specifically required are presented in the General Information section. The following sections correspond to the required items listed in Section 6.6.a. of the Technical Specifications.
- 2. General Information
- a. Key AFRRI personnel (as of 31 DEC 2024):
AFRRI Institute Director - CAPT Gerald Burke, USN AFRRI Deputy Director - Col Susan Whiteway, USAF AFRRI Chief of Staff - LTC Karen Thomas, USA Radiation Sciences Department (RSD) Head - Andrew Cook (SRO)
AFRRI 2024 Annual Report
Page 4 of 17 Radiation Safety Officer (RSO) - MAJ Jacob Vincent, USA Reactor Facility Director (RFD) - Andrew Smolinski (SRO)
Reactor operations personnel:
Reactor Operations Supervisor (ROS) - Benjamin Knibbe (SRO)
Training Coordinator - Benjamin Knibbe (SRO)
Other reactor operators:
Mathieu Brener (SRO)
Addison Guynn (SRO)
Operator candidates:
MAJ Andrew Ng, USA (AFRRI Executive Officer)
MSG Liberio Miguelpablo, USA SFC John Wilson, USA Kyrone Riley Newly licensed operators:
None Additions to reactor and support staff in 2024:
Kyrone Riley Departures in 2024:
None
- b. There were four changes to the Reactor and Radiation Facilities Safety Subcommittee (RRFSS) during 2024:
Joe Pawlovich, Health Physicist, US Naval Research Laboratory - retired 30 NOV 2024 Thomas Regan, Senior Reactor Engineer, University of Massachusetts Lowell Research Reactor (UMLRR)- replaced Leo Bobek 11 JUL 2024 Andrew Smolinski, Reactor Facility Director (RFD) - Assumed role from Andrew Cook 13 JUL 2024 Benjamin Knibbe, Reactor Operations Supervisor (ROS) - Assumed role from Andrew Smolinski 13 JUL 2024 Per the requirements in Section 6.2.1.1 of Technical Specifications for the TRIGA Mark-F reactor at AFRRI, the RRFSS consisted of the following members as of 31 DEC 2024:
RSC Chair and Director's Representative - Col Susan Whiteway Radiation Safety Officer - MAJ Jacob Vincent Radiation Sciences Department (RSD) Head - Andrew Cook Reactor Facility Director (RFD) - Andrew Smolinski Health Physics Specialist (External) - Vacant
AFRRI 2024 Annual Report
Page 5 of 17 Reactor Operations Specialist (External) - Jere Jenkins Reactor Operations Specialist (External) - Thomas Regan Approved Alternates:
AFRRI Chief of Staff - LTC Karen Thomas AFRRI Executive Officer - MAJ Andrew Ng Assistant Radiation Safety Officer (ARSO) - Catherine Benton Reactor Operations Supervisor (ROS) - Benjamin Knibbe Two meetings were held in 2024:
11 JUL 2024 18 DEC 2024
- 3. Facility Operations Summary A summary of changes to the facility design, performance characteristics, administrative procedures, and operational procedures related to reactor safety, as well as the results of surveillance testing, are provided in this section.
- a. Facility Design Changes (1) License Amendment Requests (LAR)
There were no License Amendment Requests submitted during 2024. However, a Phase 0 meeting was held with NRC personnel on 14 FEB 23 for a proposed LAR No. 27 for the AFRRI TRIGA Mark-F Operating License R-84. This LAR is still in draft awaiting submission. The LAR included changes to the Technical Specifications related to:
Update to the organization structure.
Updating qualification requirements for Reactor Facility Manager and ROS to align with standard American National Standard (ANS) 15.4.
Allowing the low source interlock to be linked to wide range logarithmic or multi-range linear nuclear instruments.
Changing the required location of Stack Gas Monitor readouts to be local and in control room, rather than control room and reactor bay.
Since the Phase 0 public meeting with the NRC, other inconsistencies in the Technical Specifications have been identified by operators that have delayed the submittal. The RSC requested that a review be conducted on alignment between ANS 15.1 and the current tech specs, and that any gaps be identified for resolution prior to the submittal.
Additional changes identified so far during this review include:
Inconsistencies in safety system interlock surveillance periodicities between Section 3.2.1 Table 3 and Section 4.2.2.b.
AFRRI 2024 Annual Report
Page 6 of 17 Inconsistency with fuel temperature scram test and check surveillances between Section 4.2.2.b, Table 2, and T.S. 4.2.3.c.
Inconsistency in Reactor Secured definition between the ANS 15.1 standard and the current definition (1.32)
No definition for Initial Startup and Approach to Power Changes stemming from these activities will be added to the request after approval by the RRFSS.
(2) Facility Modifications (FM)
Two facility modifications were completed in 2024 requiring 50.59 evaluations:
FM-015: The lead door seal-in logic, time delay, and bypass switch indication in the facility interlock system was modified. Approved by RSC on 15 JUN 23. Final installation and testing completed 02 APR 2024.
FM-020: Nuclear Instrumentation Detector Positioning System. This modification modified the mounting and positioning mechanism for nuclear instrumentation detectors over the core. It provides for more precise positioning and substantially reduces dose to personnel during power calibration. Approved by RRFSC on 23 OCT 2024. Final installation and testing completed 23 DEC 2024
- b. Performance Characteristics There were no changes to the performance characteristics of the core during 2024. All fuel elements and control rods remained in place for operations throughout the year until 25 NOV 24, when the annual maintenance shutdown began. Fuel inspections for fuel followed control rods (FFCRs), and control rod inspections were completed with no new degraded fuel or control rods identified. Rod calibrations, thermal power calibration, and power coefficient of reactivity surveillances performed from November 25 through January 2, 2025 confirmed that core performance agreed with previous operational data.
- c. Operational and Administrative Procedures There was one procedure requiring 50.59 evaluation. New procedure 299, Magnet Power Inhibit for Testing, was created. Procedure 299 controls temporary removal of the magnet power and transient rod solenoid relays, which prevents coupling of controls rods to the drives. This allows testing of the control systems and movement of rod drives while ensuring the reactor remains shutdown. Since this procedure enables the reactor control system to be operated in a manner different than what was described in Chapter 7 of the SAR, this procedure screened into a 50.59 evaluation and RRFSC review and approval was required prior to implementation per Procedure 553 Writing and Modifying Procedures. Procedure 299 was unanimously approved by the RRFSS by email vote 12/06/24.
AFRRI 2024 Annual Report
Page 7 of 17 There were several updates to the Operational Procedures during 2024. The changes do not adversely affect reactor operations or safety. The revised procedures were approved by the RFD and reviewed by the RRFSS:
001 Reactor Startup Checklist 004 Scrams, Alarms, and Abnormal Conditions 009 Exposure Room Entry 240 Makeup Water System 010 Conduct of Experiments 551 Facility Modification 011 Exposure Room Dosimetry and Experiments 100 Maintenance, Checks, Surveillance and Administrative Activities 102 Monthly Checklist (twice) 103 Quarterly checklist 110 Corrective Maintenance 104 Semi-Annual Checklist 200 Fuel Movement and Inspection 105 Annual Checklist 221 Primary Water RTD Test and Calibration There were two new Administrative Procedures implemented in 2024. The changes do not adversely affect reactor operations or safety. The revised procedures were approved by the RFD and reviewed by the RRFSS.
110 Corrective Maintenance (Initial Issue) 551 Facility Modification (Initial Issue)
- d. Results of Surveillance Tests and Inspections All maintenance and surveillance tasks during 2024 were accomplished as normally scheduled during the year, including those tasks involving the reactor fuel, instrumentation, control rod drives, and other related components. The annual maintenance and surveillance outage were during the month of November and December 2024. FFCR, control rod, and control rod drive mechanism inspections were completed with no new degraded fuel or control rods identified.
There were nine reactor malfunctions and 50 corrective maintenance items identified during 2024. Refer to sections 2 & 6 below.
Annual Technical Specification Audit - The 2024 annual reactor audit required by the reactor technical specifications included:
Conformance of facility operation to the Technical Specifications (TS) and the license Results of all actions taken to correct deficiencies occurring in facility equipment, structures, systems, or methods of operation that affect safety Performance, training, and qualifications of the reactor facility staff Reactor Facility ALARA Program The audit report indicated no technical specification violations and no major discrepancies in reactor operations, maintenance, or documentation. The audit identified some minor
AFRRI 2024 Annual Report
Page 8 of 17 documentation findings, highlighted known degradations in facility equipment that are being worked through by facility staff, and provided suggested changes and improvements. A summary of positive, negatives, and facility corrective actions stemming from the audit are summarized in the table below Annual Audit Summary Positives Special commendation for control and documentation of the degraded element inspection (CM 24-025).
Draft Procedure 000 Technical Specification Implementation is a good reference and makes audits easier. Issue this procedure formally.
Using an outside vendor (Pace Labs) for quarterly sample analysis is satisfactory and professionally done.
The corrective action program is appropriately sized and implemented for the small facility.
SCWE - A healthy working relationship between HPD and Ops Reactor Team was observed.
The ALARA Program is effective but with some documentation flaws.
Regarding previous audit findings, there was noted improvement. There were still some signature discipline issues, but they were occurring less frequently.
Negatives The facility is critically understaffed for the increased operations tempo, raising the risk of potential burnout.
The secondary cooling system is in disrepair. Continue working to improve the system.
The ventilation system differential pressure issues during abnormal alignments, identified during smoke testing, need to be addressed. Continue working to improve the system.
The documentation flow-through after the radiation safety committee (RSC) and radiation facilities subcommittee (RXSC) were consolidated missed several key documents. E.g., the radiation protection program (RPP) document, health physics procedures (HPPs), and documents referencing the program requirements had conflicting information and still had references to the RXSC.
Several projects have been left in a paused state, which is a challenge for cleanliness and housekeeping and has the potential to create transitory hazards.
AFRRI technical specification review identified two discrepancies:
o Align personnel quals for ROS and RFD in the technical specifications to 15.1/15.4 standards.
o Correct the inconsistency between Tech Spec 6.2.1.1.b.1, 6.2.3.1, and 6.2.3.3 for appointment of and voting by alternates for the Reactor and Radiation Facility Safety Subcommittee (RRFSS).
The requalification program should be revised:
o Clarify weekly checklist and shutdown checklist performance, since checks were relocated to the startup checklist, reactor operations procedure, and end of day checklists.
o Clarify requirements for late-in-cycle entry into the program based on when a new operator license is granted.
There are still some minor signature discipline issues, particularly in startup checklist performance.
Focus on attention to detail.
AFRRI 2024 Annual Report
Page 9 of 17 Corrective Actions Issue new Procedure 000 Technical Specification Implementation formally (PC-073)
Corrective maintenance is being pursued to replace the heat exchanger, add filtration (FM-026),
and replace and/or refurbish the cooling tower for the secondary cooling system. Quotes for options are being investigated.
The ventilation system is being addressed through the LINAC ventilation modification (FM-030).
Requalification program to be revised and submitted to NRC for approval (CA033)
Radiation Protection Program (RPP) document is being revised (CA034)
Incorporate changes to tech specs in next License Amendment Request (LAR-28) (CA035)
NRC Inspections - A routine NRC inspection of reactor facility operations was conducted by Mr. Andrew Waugh, Mr. Juan Arellano, and Mr. Jared Nadel from 15 JUL 2024 to 18 JUL 2024.
The inspection resulted in no new violations or findings of significance. The results of the inspection are documented in Armed Forces Radiobiology Research Institute - U.S. Nuclear Regulatory Commission Safety Inspection Report No. 05000170/2024201, dated 26 AUG 2024.
[ML24222A722]
The triennial NRC security inspection of the reactor facility was conducted by Mr. Juan Arellano, and Mr. Jared Nadel from 15 JUL 2024 to 18 JUL 2024. The inspection resulted in no significant security concerns or findings of non-compliance. The results of the inspection are documented in Armed Forces Radiobiology Research Institute - U.S. Nuclear Regulatory Commission Security Inspection Report No. 05000170/2024410, dated 16 SEP 2024.
[ML24239A350]
- 4. Core Burnup Characteristics
- a. Energy Generated by the Reactor Core:
Month Kilowatt-Hours Energy Summary January 501.4 Total energy generated in 2024: 15,069.1 kWh February 1,456.8 Total energy on fuel elements: 1,219,626.7 kWh March 305.6 Total energy on FFCRs*: 487,019.9 kWh April 780.2 May 1,017.8 June 3,673.0 July 1,924.9 August 206.4 September 157.8 October 371.6 November 115.0 December 4,573.7
- Fuel-followed control rods TOTAL 15069.1
AFRRI 2024 Annual Report
Page 10 of 17
- b. Pulse Summary:
Total pulses this year > $2.00: 0 Total pulses on fuel elements > $2.00: 4,219 Total pulses on FFCRs* > $2.00: 107 Total pulses this year: 0 Total pulses on fuel elements: 12,201 Total pulses on FFCRs*: 2,436
- 5. Unscheduled Shutdowns
- a. There were 9 unscheduled shutdowns in 2024 (all safety systems performed as designed):
Scram #
Date Description 0017 02 July 2024 UIT Computer Watchdog Scram - Memory Error 0018 17 July 2024 CCS Computer Watchdog Scram 0800 - Watchdog module momentary 0019 17 July 2024 AC Power Loss Scram - Power Flicker 0020 24 July 2024 CCS Computer Watchdog Scram 0800 - Watchdog module momentary 0021 25 July 2024 AC Power Loss Scram - Switching During Load Testing 0022 21 Aug 2024 Manual Scram - Unannounced Fire Drill 0023 09 Sept 2024 CCS Computer Watchdog Scram 0800 - Watchdog module momentary 0024 28 Oct 2024 NPP Com Alarm During Operation - Manual Scram 0025 10 Dec 2024 NFT-2 Spurious High Temp Scram - Intermittent connection/junction problem
- b. Related Corrective Actions None of the unscheduled shutdowns were reportable events, and no operating limits were exceeded. The UIT watchdog scram was a memory buffer error. All safety systems operated as designed upon receipt of the UIT watchdog signal. The system was restarted per manual guidance and the error has not reoccurred since.
The two AC power loss scrams were caused by momentary losses of power from the substation. The second occurrence coincided with the emergency diesel generator load test and the generator operator shut down the already running diesel generator due to unexpected indications. All safety systems operated as designed upon receipt of the loss of AC power signal.
The spurious scrams initiated by the CCS watchdog consistently at 0800 EDT every few days/weeks have been experienced at a similar facility (INL). It appears to be an operating system issue with LINUX SUSE 12.3. All safety systems operate as designed upon receipt of the signal. An operating system upgrade resolved the issue at INL, and a similar upgrade is in final testing phase (FSM-004).
The NPP Com alarm event matched the description of a single ethernet data packet loss from the NPP nuclear instrument high flux channel. No operating limits were exceeded. The channel selfrestored and the alarm cleared before an automatic scram occurred. The operator manually scrammed the reactor per procedure guidance upon receipt of the alarm as a conservative
AFRRI 2024 Annual Report
Page 11 of 17 measure. All safety systems operated as designed. The error has not reoccurred during operation since.
- 6. Safety-Significant Maintenance
- a. Corrective Maintenance (CM) - 50 corrective maintenance items, 26 safety-related:
Maintenance effecting safety systems for 2024 is outlined in the table below, grouped by systems. The condition of the secondary cooling system and the problems with pulsing nuclear instrumentation are the most impactful maintenance items for the facility research needs, however, these items are not preventing overall safe operation of the facility.
Maintenance Affecting Safety Systems CM Tracking#
Date Description Secondary Cooling 23-041 25 Oct 2023 07 Jun 2024 Secondary cooling system investigation -
Secondary cooling system is ineffective Chemical Cleaning completed 6/7/24 - Major (temporary) improvement but more work is needed.
Heat exchanger is fully clogged. Back-flushing is ineffective. Heat Changer replacement needed.
Cooling tower is leaking.
Identified drainage issues with Warm & Hot drains during cooling system draining. Drains repaired with plumbing contractor 24-004 11 Jan 2024 City water supply valve leaked from abandoned supply piping branch which was still connected. Cut and capped the line. Supply feeds normal pool makeup water system, cooling tower makeup water, and supply ventilation chilled water.24-022 17 Jul 2024 Cooling tower fan electrical phase imbalance (Fan OOS)
Nuclear Instrumentation 24-009 28 Mar 2024 NI Com error testing - Identified that NI ethernet communication errors do not open the scram loop (de-energize K1), however drop rods via software.
Procedure 004 modified to press Manual scram on Com errors to place the scram loop in a de-energized state.24-017 28 Jun 2024 NFT-2 intermittent signal - One of 2 TCs in C-ring - Connector repaired 24-020 15 Jul 2024 NFT Screen - Repaired during December Calibration 24-030 08 Oct 2024 NLW electrical noise during transient rod drive movement.24-031 09 Oct 2024 NP Screen - Repaired during December calibration 24-034 04 Nov 2024 NLW 1kW pulse inhibit trip setting too high - procedure issue 24-035 06 Nov 2024 NPP Pulse Channel Testing-Troubleshooting NPP with vendor (GA)24-044 10 Dec 2024 NFT-2 scram troubleshooting - Identified junction problem. Evaluating replacements24-049 15 Dec 2024 NPP Pulse Capture Prototype testing with vendor (Plantation Productions)
Control Rod Drives24-008 01 Mar 2024 Transient rod air system leak - Repaired coincident with semi-annual inspection 24-018 09 Jul 2024 Shim Rod Down Limit Switch Adjustment 24-039 02 Dec 2024 Reg Rod Drive Magnet Power Lead Degraded - solder repair
AFRRI 2024 Annual Report
Page 12 of 17 Maintenance Affecting Safety Systems CM Tracking#
Date Description 24-040 04 Dec 2024 Safe Rod Drive Hitching Movement - rack and pinion gears replaced 24-041 05 Dec 2024 Transient Rod Drive Air Leak 24-042 05 Dec 2024 Reg Rod Drive Pinion Gear Set Screw Adjustment 24-043 06 Dec 2024 Reg Rod Drive Down limit switch digital input signal connector loose 24-050 17 Dec 2024 Reg Rod Drive Position Incorrect - potentiometer belt twisted.
Fuel 24-025 04 Sep 2024 Degraded Fuel Element 3295-E Inspection (NRC Inspection IFI)
Console Components23-047 28 Feb 2024 UPS Self-Test fixed - Cause of multiple scrams in 2023 Radiation Area Monitors24-010 25 Mar 2024 Replaced RAM R2 detector head (like for like)24-014 06 Jun 2024 Replaced E6 RAM electronics module (like for like)
Other 24-012 12 Apr 2024 Stack Volumetric Flow indication intermittent failure - still open. Flow is trended and monthly average is input into Ar-41 calculations.24-047 12 Dec 2024 Bulk Pool Temp Sensor Connector Repair
The condition of the secondary cooling system is poor. The primary/secondary heat exchanger and cooling tower do not perform its function adequately, limiting continuous full power operations to a few hours before pool temperature approaches the tech spec limit and the reactor must be shut down. The plate-type heat exchanger is completely clogged. There is no filter in the secondary system, and the open cooling tower allows debris (e.g., leaves and dust) to be carried throughout the system. The cooling tower and piping was chemically cleaned to remove scale build-up throughout the carbon and galvanized steel system in June 2024. The improvement was good, improving differential pressure from 30 psid to 17 psid across the heat exchanger. During a repeat performance of the endurance test in June 2024 after cleaning, continuous operation was achievable even during hotter outside conditions. However, success was short-lived, within a month differential pressure had risen again to 30 psid, indicating a need for a second chemical cleaning evolution or a rebuild of the system. During the heat exchanger cleaning several hot and warm drains were found clogged. This has since been repaired through a plumbing subcontractor.
In addition, the cooling tower has several maintenance needs. The cooling tower leaks, the three-way valve that controls flow to the fins has had multiple failures due to wear and corrosion, and the cooling tower fan is out of service due to a phase imbalance that is awaiting repair through the maintenance contractor.
A design change is in progress to improve the long-term state of the system. Options may include replacing the cooling tower with stainless steel or a closed loop system, adding filtration to the system, replacement of the heat exchanger, and targeted replacement of carbon steel components in the cooling water piping. Capability to perform long duration high power operations will impact new planned experiments in 2025. Until fully addressed, operations will continue to be limited to ensure tech spec compliance.
Nuclear instrumentation safety significant maintenance in 2024 included all channels. Two activities were related to the NPP pulse capture modifications to restore pulsing capability, one
AFRRI 2024 Annual Report
Page 13 of 17 by Plantation Productions and one by General Atomics (GA). GA was onsite 11/6/2024 to perform site testing and troubleshooting. The testing during the visit revealed a software problem in the NPP module at the root of the data capture and transfer problems. The internal watchdog trip and data transfer problem could be replicated. GAs resolution of the problem will require software changes to the NPP firmware. The Plantation Productions solution is the Pulse Power Capture device (PPCapture), a variation of a system deployed at UT-Austin and was tested 12/15/2024 at AFRRI. The device uses the NPP analog hardware to provide a signal to a separate data acquisition unit using a spare isolation amplifier output. It will require hardware and console software modifications to implement. Either solution will require at least a 50.59 evaluation and will be presented to the RRFSS for approval before implementation. Both testing activities utilized procedure 299 to ensure control rods remained decoupled, and the system was restored to its original configuration after the testing.
Maintenance on the wide range logarithmic channel (NLW), which is responsible for the period signal and interlocks, included troubleshooting for noise and the recalibration of the 1kW pulsing interlock. Electrical noise on the NLW from movement of the AC/DC transient rod drive motor produces high period spikes, triggering the fast period interlock, and complicating transient rod withdrawals during startup. The noise was partially addressed with cable rerouting and connector repair. A transient rod drive modification that converts the drive mechanism to a low voltage stepper motor should help resolve the noise issues. This modification is expected to be completed in 2025. The 1 kW pulsing interlock on the NLW was found incorrectly set. This was due to a procedure discrepancy that input the incorrect current signal during calibration. The channel was recalibrated. The miscalibration had no impact on the facility since the interlock is only required for pulsing and pulsing activities were restricted for the duration of 2024 due to the NPP issues.
Screens on the nuclear instrument modules periodically go blank. These are due to corrosion on a connector for the local screen. Both the NP and NFT modules experienced these failures in 2024. These do not affect data transfer to the console, and are being repaired as the units are taken out for annual calibration. Screens are not utilized for normal operations and their failure did not affect normal operations.
The NFT-2 temperature indication spiking occurred twice in 2024. One was attributed to a connector problem, and the other, which caused Scram 0025, was traced to a likely junction problem. Tech specs can be met with NFT-1 (B-ring) and NFT-3 (C-ring), so NFT-2 channel was taken out of service. Troubleshooting included connecting the thermocouple (TC) previously connected to NFT-2 channel and all available spare instrumented fuel element (IFE) TCs in the core to an auxiliary recorder to trend performance. When hooked up to an auxiliary recorder, independent of the NFT-2 electronics package, the TC spiking was visible. When a suitable IFE/TC combination is found, channel NFT-2 will be restored. This may require relocation of the instrumented element in the F-ring, a relatively new element placed there for beginning of life conditioning in 2016, to the C-ring.
There were several repairs done on control rod drive mechanisms (CRDMs) in 2024. Most of these are relatively simple wear and tear repairs like limit switch adjustments, air leaks, solder repairs, and set screw adjustments. The high number of control rod drive maintenance items in December was somewhat expected; during the annual outage these systems were fully disassembled and inspected. Drives were repaired with operating manual guidance and post-
AFRRI 2024 Annual Report
Page 14 of 17 maintenance surveillances completed to restore operability before reactor operation.
A degraded fuel element 3295E was inspected in 2024, prompted by a question on serial number verification asked during the triennial security inspection. The element had been sealed in an aluminum storage can since 1989. A 1989 VHS tape of the element being sealed up was reviewed prior to the inspection. The element was not breached at that time, but had a large bulge on one side and significant bowing. When unsealed the element appeared intact, but the bulge documented in the 1989 video is clearly visible. The element is bowed extensively and would not fit in the new canister. In addition, the stainless-steel fuel cladding showed surface corrosion and was clearly in contact with the old aluminum storage canister wall for an extended period of time. The decision was made to keep the element in a fuel storage rack where water quality is properly monitored and maintained, rather than sealed in a container. It will not be used again in the core.
The uninterrupted power supply (UPS) was reconfigured to remove the software-driven bi-weekly self-test, which was responsible for multiple unexpected scrams in 2023. This has no impact on normal performance or the Loss of AC Scram function. The system was retested following the change to ensure surveillances were satisfied and operability restored before reactor operation.
Two radiation area monitors (RAMs) were repaired in 2024 with like-for-like components.
One item replaced the detector head on R2 for the reactor bay. Tech specs were satisfied with R1 and R5 operable, two are required per tech specs. The E6 RAM had the electronics module replaced with a like for like spare unit. E6 is required for operations in region 3. Operations in the region were restricted until the system restored. Both RAMs were recalibrated and surveillances performed before return to operation.
Volumetric stack flow is trended for use in quarterly Ar-41 calculations. The monthly average is used. The sensor has been experiencing an intermittent failure of several minutes duration approximately once or twice a month. The failure is readily identified on the chart recorder and can be accounted for in calculations. The maintenance item is still open as troubleshooting continues to identify the fault.
The bulk pool temperature sensor was found failed during prestart checks. The sensor is required to monitor bulk pool temperature to ensure compliance with tech spec limits. The connector was repaired and retested before operations continued.
- b. Preventative Maintenance All maintenance and surveillance tasks during 2024 were accomplished as normally scheduled during the year, including those tasks involving the reactor fuel, instrumentation, control rod drives, and other related components. The annual maintenance and surveillance outage were during the month of November and December. Fuel FFCR and control rod and drive inspection were completed with no new degraded fuel or control rods identified.
AFRRI 2024 Annual Report
Page 15 of 17
- 7. Changes affecting the Safety Analysis Report (SAR)
(Made Pursuant to 10 CFR 50.59 and Summaries of 50.59 Safety Evaluations)
- a. Facility Changes that Affect the Description in the SAR There were two facility modifications were performed that required 50.59 evaluations that affect the description in the SAR:
FM-015: The lead door seal-in logic, time delay, and bypass switch indication in the facility interlock system was modified. The change modified the seal in-logic to ensure anytime lead door movement was stopped, positive operator action was required to restart door movement. It shortened the time delay from 3 minutes to 30s for lead door movement to minimize the time to retrieve experiments in the exposure room. It also provided positive indication of exposure room horn bypass switches at the exposure room door controls to minimize the potential of missing a Tech Spec surveillance of 2-licensed operator visual verification of room clearance whenever the horns are bypassed. The modification was approved by the RRFSS on 15 JUN 23. Final installation and testing completed 02 APR 2024. Figures and descriptions are being updated in the SAR.
FM-020: Nuclear Instrumentation Detector Positioning System. This modification modified the mounting and positioning mechanism for nuclear instrumentation detectors over the core. It provides for more precise positioning and substantially reduces dose to personnel during power calibration. It was approved by the RRFSC on 23 OCT 2024. Final installation and testing were completed 23 DEC 2024. Details of the detector mounting and positioning during calibration are being added to Chapter 7.
- b. Procedure Changes that Affect the Description in the SAR
Several reactor administrative and operating procedures were in 2024. There was one procedure requiring 50.59 evaluation. New procedure 299, Magnet Power Inhibit for Testing, was created. Procedure 299 controls temporary removal of the magnet power and transient rod solenoid relays, which prevents coupling of controls rods to the drives. This allows testing of the control systems and movement of rod drives while ensuring the reactor remains shutdown. Since this procedure enables the reactor control system to be operated in a manner different than what was described in Chapter 7 of the SAR, this procedure screened into a 50.59 evaluation and RRFSC review and approval was required prior to implementation per Procedure 553 Writing and Modifying Procedures. Procedure 299 was unanimously approved by the RRFSS by email vote 12/06/24. Changes describing the method of de-coupling utilized in the procedure are being added to the Chapter 7 descriptive section.
AFRRI 2024 Annual Report
Page 16 of 17
- c. New Experiments or Tests Not Encompassed in the SAR
The experiment program in 2024 doubled its output from 2023. The 45 experiment campaigns performed at the reactor in 2024 is the highest rate of output since before 1995. Only routine experiments covered under existing routine reactor authorizations or reactor parameter authorizations, T.S. 6.4.b. and T.S. 6.4.c respectively, were performed in 2024. No new experiments or tests were performed during the reporting period that were not encompassed by the final safety analysis report (FSAR).
- 8. Radioactive Effluents
- a. Liquid Waste: One radioactive liquid discharge from the Hot and Warm waste tanks of 17,150 gallons was performed on July 12, 2024. The following table summarizes the discharge. All isotope concentrations were below state and federal regulatory limits.
- b. Gaseous Waste: There were no particulate discharges in 2024. The total activity of Argon-41 discharged in 2024 was 5.774 curies. The estimated effluent concentration from the release of Argon-41 represents 1.82% of the constraint limit for unrestricted areas (10 CFR 20.1101(d) and Table 2, Appendix B, 10 CFR 20).
Radionuclide Activity (mCi/L)
Activity (mCi/mL) 10 CFR 20 Appendix B Table 3 Monthly Average Concentration Limit Fraction of 10 CFR 20 Appendix B Table 3 Monthly Allowable Concentration Limit Code of Maryland Regulations (COMAR) 26.12.01.01 Part D Appendix B Table III Monthly Average Concentration Limit Fraction of Code of Maryland Regulations (COMAR) 26.12.01.01 Part D Appendix B Table III Total Activity (Ci)
(17,150 gallons)
AM-241 4.95932E-06 4.95932E-09 2.00E-07 2.47966%
2.00E-07 2.47966%
0.322 BI-214 3.30628E-06 3.30628E-09 3.00E-03 0.00011%
3.00E-03 0.00011%
0.215 CD-109 1.48899E-05 1.48899E-08 6.00E-05 0.02482%
6.00E-05 0.02482%
0.967 CS-137 3.22072E-06 3.22072E-09 1.00E-05 0.03221%
1.00E-05 0.03221%
0.209 K-40 2.71325E-05 2.71325E-08 4.00E-05 0.06783%
4.00E-05 0.06783%
1.761 MO-99 8.34371E-08 8.34371E-11 2.00E-04 0.00004%
2.00E-04 0.00004%
0.005 PA-234M 4.85136E-05 4.85136E-08 3.00E-04 0.01617%
3.00E-04 0.01617%
3.149 PB-212 2.37684E-05 2.37684E-08 2.00E-05 0.11884%
2.00E-05 0.11884%
1.543 PB-214 2.47426E-06 2.47426E-09 1.00E-03 0.00025%
1.00E-03 0.00025%
0.161 TH-232 1.96275E-04 1.96275E-07 3.00E-07 65.42500%
3.00E-07 65.42500%
12.742 TC-99M 4.83313E-07 4.83313E-10 1.00E-02 0.00000%
1.00E-02 0.00000%
0.031 U-235 8.23402E-05 8.23402E-08 3.00E-06 2.74467%
3.00E-06 2.74467%
5.346 70.91%
70.91%
26.451 TOTAL MONTHLY FRACTION =
AFRRI 2024 Annual Report
Page 17 of 17 Quarter Argon-41 JAN - MAR 2023 1.021 Ci APR - JUN 2023 1.302 Ci JUL - SEP 2023 1.042 Ci OCT - DEC 2023 2.409 Ci 2024 Total 5.774 Ci
- c. Solid Waste: All solid radioactive waste material is transferred to the AFRRI byproduct license; none was disposed of under the R-84 reactor license.
- 9. Environmental Radiological Surveys
All environmental sampling of soil and vegetation yielded radionuclide levels within the background range. The radionuclides that were detected were those expected from natural background and from long-term fallout from nuclear weapons testing.
- 10. Exposures Greater Than 25% of 10 CFR 20 Limits There were no doses to reactor staff personnel greater than 25% of 10 CFR 20 occupational limits. No visitors were exposed to doses greater than public radiation dose limits.
- 11. Conclusion 2024 was an incredibly productive year for the TRIGA Mark-F reactor at AFRRI. This can be attributed to more qualified staff, effective maintenance, better equipment reliability, and process improvements. Experiments and facility utilization are now proceeding at a pace on par with pre-1995 levels, as the Department of Defense has recognized the AFRRI reactor as a critical asset to their portfolio for radiobiology research, education, and materials testing. AFRRI is looking forward to further research, leadership, training, and education in 2025.