ML25233A276
| ML25233A276 | |
| Person / Time | |
|---|---|
| Site: | University of Utah |
| Issue date: | 08/22/2025 |
| From: | Goodell E Univ of Utah, Salt Lake City |
| To: | Tony Brown Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| Download: ML25233A276 (1) | |
Text
22 August 2025 From: Dr. Edward Goodell, Reactor Facility Director University of Utah TRIGA Reactor Facility (Docket: 50-407) 110 Central Campus Drive, Room 2000, Salt Lake City, UT 84112 To: Document Control Desk Tony Brown, Chief of Non-Power Production and Utilization Facility Oversight Branch Jessica Lovett, Project Manager for the University of Utah Subj: UUTR Request to use an alternate location for Special Refresher Training
Dear Jessica Lovett and Tony Brown,
In accordance with UNIVERSITY OF UTAH - APPROVAL OF EXEMPTION FROM THE REQUIREMENTS OF 10 CFR PART 55, OPERATORS LICENSES (EPID L-2024-NLE-0003) DATED: MAY 16, 2025 (ML2507A203), the NRC asserted its authority under 10 CFR 55.59(b) to require UUTR to complete additional training before returning to licensed duties. The letter then references that reactivity manipulations will be performed at a facility similar to UUTR in accordance with 10 CFR 55.59(c)(3)(i). In UUTRs letter dated February 10, 2025 (ML25050A613), UUTR cited Reed Research Reactor as the desired similar design facility to perform refresher training. Due to an unplanned shutdown of the Reed Research Reactor, UUTR requests NRC approval to use Kansas State University as an alternative location for special refresher training.
Based on previous correspondence with the NRC concerning approval for the special refresher training, UUTR submits the following information comparing UUTR to the KSU reactor for NRC review as justification to use the KSU reactor as an adequate alternative for annual training:
Reactor Design Comparison: UUTR and the KSU reactor are both water-moderated, water-cooled thermal reactors operated in an open pool. UUTR features a hexagonal core containing 78 aluminum/stainless-steel cladding fuel elements with 3 control rods located in the D ring. KSU has a circular design of 83 stainless-steel TRIGA fuel elements with 4 control rods located in various rings of the core. Both UUTR and KSU use a fission chamber for monitoring reactor power in the source range and for an interlock that prevents control rod withdrawal for a neutron count rate below 2 cps. This fission chamber serves as a wide-range log channel in the same way for both facilities; as power rises out of the source range, the instrument switches to measuring current to monitor reactor power in the power range.
Both facilities use a compensated ion chamber as a wide range linear monitor that automatically ranges to display the correct decade of reactor power. Both UUTR and KSU reactor have high power scrams attached to signals provided by the uncompensated ion chamber and compensated ion chamber.
A key difference between UUTR and the KSU reactor is the pulse capability of KSU. Both reactors utilize standard TRIGA control rods containing boron carbide. In addition to the safety, shim, and regulating rod possessed by UUTR, KSU reactor has a borated graphite transient rod that enables pulsing operations. However, the transient rod can also be operated for steady-state operations similar to the other control rods. UUTR rod positions are indicated as a percentage of withdrawal while the KSU reactor rod position is indicated by arbitrary units of nominally 100 for rod down to nominally 1100 units for rod up.
See Table 1 for an explanation of the differences in power display provided by reactor instrumentation.
Console Design Comparison: Both consoles contain the same interlocks to prevent simultaneous rod withdrawal of more than one control rod and rod withdrawal on low source counts at below 2cps. Both consoles are controlled by a raise and lower button for each control rod and have indications activated by limit switches for when each control rod is at the top or bottom of travel. Both consoles provide a digital chart recorder to display reactor power and have reactor power displays from the three instruments prominently in front of the operator. Both facilities have a similar coolant system with the same parameters of heat exchanger temperatures and flow rates displayed at the console. Both facilities have multiple area radiation monitors with displays at the console. Both consoles display at least one instrumented fuel temperature. See Table 1 for an explanation of the differences between the consoles to include power display provided by reactor instrumentation and reactor scrams. One important difference is that UUTR has a digital system to provide a concise view of control rod positions, reactor power from three instruments, and the status of auxiliary systems on two computer screens.
Reactivity Response: A key difference between UUTR and KSU is the reactivity response from the control rods. All UUTR Control Rods move at approximately 11 inches/minute. KSU control rods vary in speed: 11 inches/minute for the shim rod, 18 inches/minute for the safety rod, and 24 inches/minute for the regulating rod. A faster control rod speed combined with a higher reactivity worth per control rod results in a faster reactivity insertion rate at KSU. KSU also has an automatic control feature for their regulating control rod. To better simulate the UUTR reactor, UUTR operators will not use the automatic control option of the regulating rod for their operating examination. KSU reactor facility Procedure No.
15 - Steady State Operation provides a table of expected 100 kW parameter values that UUTR operators can use.
Table 1: Summary of Key Differences between the UUTR and KSU Characteristic UUTR KSU Reactor design Hexagonal design for 126 element holders up to G ring Circular design consisting of 91 element holders up to F ring Power Limit 100kW 1250kW Uncompensated ion chamber (percent channel) range 0.001 to 150%
0 to 100%
Control Console Digital Displays relayed from Analog instrumentation drawers Analog Displays Control Rod Speed 11 inches/minute for all rods Shim: 11 inches/minute Safety: 18 inches/minute Regulating: 24 inches/minute Transient: 20 inches/minute (Steady state mode)
Control Rod Worth Safety: $2.00 Shim: $1.5 Regulating: $0.40 Safety: $1.71 Shim: $2.01 Regulating: $0.93 Transient: $2.72 Fuel Temperature Display C-ring and D-ring instrumented fuel element display B-ring instrumented fuel element display Shutdown Margin Minimum $0.50 Minimum $0.50 Excess Reactivity Maximum $1.20 Maximum $4.00 Reactor Scrams Linear Channel: 100 kW (100%)
Power Channel: 100%
High Fuel Temp: 200C low pool water level, high fuel temperature, magnetic key scram, scram on loss of power.
Manual Scram button located by interlock display lights Linear Channel: 104%
Power Channel: 104%
High Fuel Temp: 450C/350C Detector HV scram at 90%
Period scram of 3.5 secs Manual Scram bar located next to control rod operation switches.
Water specification display pH, conductivity, and bulk water temperature at 4 heights are displayed on console. Primary and Secondary Heat Exchanger inlet/outlet temps Conductivity, activity, bulk water temperature at 2 heights, and cleanup loop water temperature are displayed on console. Secondary loop, cooling tower water return, and primary loop heat exchanger inlet temperatures displayed in bay.
Coolant system Operated at console by clicking on a pump icon for auxiliary system digital display.
Operated by a pushbutton on console to energize appropriate pumps and control panel in bay.
Area Radiation Monitors (ARM)
Console digitally displays readings from 4 ARMs throughout the facility.
Console has analog display for ARMS.
See attached letter from the KSU reactor facility confirming their agreement to utilize their reactor and its licensed operators to meet the special refresher training requirements.
UUTR confirms operating power levels at the selected facility will be at or as near as possible to the UUTRs licensed power of 100kW. The reactivity manipulations performed at the selected facility will be in accordance with 10 CFR 55.59(c)(3)(i). Both Andrew Allison and Edward Goodell will make 4 power manipulations: (1) from reactor shutdown, perform reactor startup to 100 kW; (2) perform a down power manipulation to 30 kW; (3) perform an up-power manipulation to 90kW; (4) shutdown the reactor. While KSU has pulse capabilities, UUTR operators will only operate the KSU reactor in steady state mode for the special refresher training.
UUTR facility confirms that the KSU reactor will only be used for special refresher training.
Following completion of the special refresher training at KSU, Edward Goodell and Andrew Allison will operate UUTR in order to perform a control rod calibration and thermal power calibration. Following the successful completion of a thermal power calibration at 90 kW with appropriate power channel adjustments as necessary, UUTR will be considered fully operational and ready for experiments/training. UUTRs next run will then be dedicated to Andrew Allison and Edward Goodell performing their annual operating examinations to satisfy the requirements of UUTRs requalification plan.
UUTR staff appreciate the timely responses from NRC staff for this request. I declare under penalty of perjury that the foregoing is true and correct. UUTR requests that the Commission approve the use of the KSU reactor as an alternate facility for the special refresher training.
Sincerely, Dr. Edward Goodell Reactor Facility Director, The University of Utah (801) 581-4188 Ted.goodell@utah.edu