ML24213A000
| ML24213A000 | |
| Person / Time | |
|---|---|
| Site: | University of Utah |
| Issue date: | 06/30/2024 |
| From: | Allison A Univ of Utah |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| Download: ML24213A000 (1) | |
Text
UUTR Annual Report 1 July 2023 - 30 Jun 20 24
The University of Utah TRIGA Reactor (UUTR)
Annual Operating Report
for the period 1 July 2023 through 30 June 2024
Andrew Allison Interim Reactor Director
Utah Nuclear Engineering Program (UNEP) 1 UUTR Annual Report 1 July 2023 - 30 Jun 20 24
I. NARRATIVE
A. Operating Experience The University of Utah TRIGA Reactor (UUTR), License No. R-126, Docket No. 50-407, was operated for 25.81 hours9.375e-4 days <br />0.0225 hours <br />1.339286e-4 weeks <br />3.08205e-5 months <br /> and generated 889.7 kilowatt-hours of thermal energy during this reporting year. The reactor was used for educational demonstrations and training, reactor systems tests, reactor power measurements, and a sample irradiation.
B. Changes in Facility Design The ventilation system was modified to allow more exhaust flow from the reactor bay.
This modification was intended to assist the facility with maintaining its negative air pressure technical specification while the building is operating in economizer mode. The fuel storage pits were re-analyzed/designed to allow for the storage of up 152 irradiated fuel elements.
C. Surveillance Tests Documentation of all surveillance activities is retained and stored by the facility. The following surveillances have been completed during the 2023-2024 operating year.
- i. Control Rod Worth The control rod worth, shutdown margin, and excess reactivity was measured on 9/13/2023 using the control rod drop method with values, as shown in Table 1. The reactor was defueled for fuel inspection/tank repair and therefore no control rod calibration will be performed until the reactor is restored. A control rod calibration will be performed following restoration from fuel inspection in 2025.
Table 1. Summary of control rod worth, SDM, and ER Core Configuration #25a Date 9/13/23 Worth ($)
Safety Rod 2.000 Shim Rod 1.517 Regulating Rod 0.283 Excess Reactivity 0.773 Shutdown Margin 1.027 eff 0.0075 ii. Control Rod Inspection Control Rod Inspection was performed during the summer of 2023 following Underwater Construction Corporations coating of tank welds. There were no significant issues identified. Control Rod Inspection will be conducted in 2025 following tank repair.
iii. Thermal Power Calibrations Calorimetric power calibration was performed on 9/18/2024 with the results shown in Table 2. The 9/18/2024 calibration was used for performing power adjustments.
Utah Nuclear Engineering Program (UNEP) 2 UUTR Annual Report 1 July 2023 - 30 Jun 20 24
Table 2. Summary of calorimetric power calibrations Date Percent Power Indication Linear Power Indication Thermal Calculated Power Level 12/21/22 86.0 90.1 86.6 iv. Fuel Inspection Fuel Inspection was performed during the summer of 2023 following Underwater Construction Corporations coating of tank welds. There were no significant issues identified. All fuel elements were verified to have no paint on them. Our storage pits contain 18 retired fuel elements to be returned to the DOE. Fuel inspection will be conducted in 2025 following tank repair.
- v. Fuel Temperature Calibration Fuel temperature channels were calibrated on 3/23/2024. The channels were calibrated to less than or equal to 2°C error over the range from 20 °C to 400 °C.
vi. Reactor Safety Committee (RSC) Audits Three RSC audits were completed during this reporting period. The data are shown in Table 3. These audits identified no significant deviations from standard operating practices.
Table 3. Audit summary Audit Period Auditor Operations and Maintenance 1 Jan. 2023 to 30 Jun 2023 Ben Huffman Operations and Maintenance 1 Jul. 2023 to 31 Dec. 2023 Don Wall Radiation Safety and ALARA 1 Jul. 2023 to 30 Jun. 2024 Masoud Beitollahi vii. Environmental Surveys 15 environmental monitors are located in the areas surrounding the University of Utah and UUTR. Table 4 shows the average dose recorded since 2011. In 2019, The University of Utah changed dosimeter manufacturer from Landuar to Mirion, resulting in the change of values from 2018 to 2019 due to background subtraction.
Table 4. Summary of environmental monitoring around the UUTR Year Average quarterly readings for the 12 environmental monitors (mrem) 2023 2.65 2022 0.71 2021 1.0 2020 0.29 2019 1.0 2018 34.56 2017 31.78 2016 31.18 2015 32.06 2014 33.81 2013 33.88 2012 35.56 2011 35.13
Utah Nuclear Engineering Program (UNEP) 3 UUTR Annual Report 1 July 2023 - 30 Jun 20 24
II. ENERGY OUTPUT The UUTR reactor was operated for 25.8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> and generated 889.7 kilowatt-hours during this reporting period. Since initial criticality, the reactor has been operated for a total of 4,677.3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> with an accumulated total energy output of 250,218.5 Megawatt*hours.
III. EMERGENCY SHUTDOWNS AND INADVERTENT SCRAMS:
One inadvertent SCRAM occurred while the reactor was shutdown, de-fueled, and secured. A nuclear diver accidentally made contact with the low-level sensor while maneuvering fuel in the core region. Corrective Action was to re-raise the safety rod and continue fuel movements.
Table 5. Summary of Inadvertent SCRAMS and Unplanned Shutdowns Date Run Number Type Cause Action 7/20/2023 2164 Pool low Diver Raise Safety rod to 100%
water IV. MAJOR MAINTENANCE A. UCC coated all accessible welds greater than 8 feet from the top of the UUTR tank with Bio-Dur epoxy to prevent reactor tank leaks. The original leak identified on east side of weld 8 feet from the bottom of the tank was successfully repaired. A second leak was identified somewhere along the circumference 10 feet from the top of the tank. UUTR staff are currently transferring all fuel out of the reactor tank into storage pits to prepare for the complete emptying of the reactor tank. UUTR intends to contract with an engineering firm for the dry repair of the reactor tank.
V. CHANGES, TESTS AND EXPERIMENTS PURSUANT TO 10 CFR 50.59 Four screenings were complete pursuant to 10 CFR 50.59. Installation of Additional UUTR exhaust ventilation and using digital chart recorder to maintain CAM logs screened out of requiring an evaluation according to 10 CFR 50.59. 10 CFR 50.59 evaluations were performed by the facility to access storing fuel elements in a stacked configuration in the fuel storage pits and performing a partial drain of the UUTR tank in support of leak identification/repair. All 10 CFR 50.59 screenings and evaluations are maintained in facility control room in the Maintenance Log.
VI. REACTOR SAFETY COMMITTEE As of the end of the reporting period, the current members of the RSC as designated by the Licensee are as follows:
Glenn Sjoden, Director, Utah Nuclear Engineering Program Andrew Allison, Reactor Supervisor Fred Monette, RSO of University of Utah Donald Wall Benjamin Huffman Greg Moffitt
Utah Nuclear Engineering Program (UNEP) 4 UUTR Annual Report 1 July 2023 - 30 Jun 20 24
Gary Sandquist
The UNEP staff continues to review and update facility documentation to assure compliance with all applicable regulations.
VII. RADIOACTIVE EFFLUENTS
A. Liquid Waste - Total activity released: 0.336mCi Tritium UUTR inner pool tank was observed to be leaking from March 25th until July 12th, 2023. Water samples were performed on 3/29/23 and 4/5/23. Analysis shows the tritium content is 0.1 nCi/mL based on measurements from a Hidex Liquid Scintillation Counter. 600 gallons of water was estimated to have leaked to the environment from July 1st, 2023 until July 12th. only 1.9mCi (1.67mCi in this reporting year and 0.23mCi of tritium in next years report) was released in the form of reactor water from this leak. A low-level particulate activity analysis was performed with 48-hour HPGe counts using 1 liter of water in a Marinelli beaker. Analysis showed Cs-137 was below minimum detectable activity. Since the leak has been repaired, there are no further concerns for radioactivity released to the environment from reactor tank water. Storm water was analyzed upstream and downstream of Merrill Engineering Building. No detectable activity was discovered. A second reactor tank leak was observed to start on September 19th, 2023 and stopped in Mid-December when water level dropped to suspected height of leak at 123.5 inches from the top of the tank. It is estimated that 3,100 gallons of water leaked into the environment for the second tank leak. The water was accessed to have an activity less than the MDA of 0.009nCi/ml. Assuming the tritium content of this water was the activity level of the MDA, an additional 0.106mCi of tritium was released from the second tank leak. Therefore, the total tritium activity released this reporting period was 0.336mCi.
B. Solid Waste - Total activity: none.
C. Gaseous Waste - Total estimated activity released: 11.08 µCi.
The UUTR was operated for 25.8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> at power levels up to approximately 90 kW. At this power level, Ar-41 production is substantially below MPC values for unrestricted areas. The minimum detectable concentration of Ar-41 from the CAM system for the stack monitor has been found to be less than two-thirds of 10 CFR 20 appendix B limits for release to unrestricted areas. The annual calculated concentration of Ar-41 generated during operation is estimated to be 4.93x10-11 µCi/ml, which is approximately 0.002% of the DAC. The total amount of Ar-41 released was estimated to be 11.08 µCi. No phosphorus-32 was released from the UUTR or associated facilities during this period. A monthly summary of gaseous releases is given in Table 6. The total amount of all gaseous radioactivity released was estimated to be 11.08 µCi.
Table 6. Summary of Monthly Gaseous Radioactive Effluent Month Power (kWh) Ar-41 (µCi) Ar-41 (µCi/ml) Estimated Release % of DAC P-32 and all others July 0 0 0 0 0.000%
Utah Nuclear Engineering Program (UNEP) 5 UUTR Annual Report 1 July 2023 - 30 Jun 20 24
August 0 0 0 0 0.000%
September 889.7 11.08 4.93E-11 0 0.002%
October 0 0 0 0 0.000%
November 0 0 0 0 0.000%
December 0 0 0 0 0.000%
January 0 0 0 0 0.000%
February 0 0 0 0 0.000%
March 0 0 0 0 0.000%
April 0 0 0 0 0.000%
May 0 0 0 0 0.000%
June 0 0 0 0 0.000%
Total 889.7 11.08 4.93E-11 0 0.002%
VIII. PERSONNEL RADIATION EXPOSURES
A. UNEP Personnel The University of Utah Radiation Safety has issued to all personnel with duties in the reactor laboratory a Mirion gamma and neutron dosimeter. The duty category and monitoring period of personnel are summarized in Table 7. A summary of the whole-body exposures to the UNEP personnel is presented in Table 8.
Table 7. Summary of Monitored Personnel Last Name First Name Start Date End Date Duty Category Allison Andrew 7/1/2023 6/30/2024 Regular Ashraful Mamun 7/1/2023 6/30/2024 Regular Cazalas Edward 7/1/2022 6/30/2024 Regular Goodell Edward 7/1/2022 6/30/2024 Regular Heayoung Yoon 7/1/2023 6/30/2024 Regular Heyen Eden 7/1/2023 12/31/2023 Regular/terminated Huntsman Matthew 7/1/2023 6/30/2024 Regular Johnson Joseph 7/1/2023 6/30/2024 Regular Mcdonald Natalie 7/1/2023 12/31/2023 Regular/terminated McFall Schuyler 7/1/2023 12/31/2023 Regular/terminated Mowes Brandom 12/11/2022 6/29/2024 Regular Olson Codey 7/1/2023 12/31/2023 Regular/terminated Quist Teancum 7/1/2023 12/31/2023 Regular/terminated Romero Michael 7/1/2023 6/30/2024 Regular Siegal Holtan 8/1/2023 6/30/2024 Regular Sjoden Glenn 7/1/2023 6/30/2024 Regular Snow Jesse 7/1/2022 6/30/2024 Regular Strong Jacob 12/13/2022 6/30/2024 Regular Wang Meng-jen 7/1/2023 6/30/2024 Regular/terminated Woods Corey 7/1/2023 6/30/2024 Regular/terminated
Utah Nuclear Engineering Program (UNEP) 6 UUTR Annual Report 1 July 2023 - 30 Jun 20 24
Table 8. Summary of whole-body exposures to the UNEP personnel Estimated whole-body exposure range (rem) Number of individuals in each range Less than 0.1 22 0.10 to 0.25 0 0.25 to 0.50 0 0.50 to 0.75 0 0.75 to 1.00 0 1.00 to 5.00 0 Greater than 5 rem 0 B. Measured Doses During the period of 7/1/2023-6/30/2024, the highest individual dose of 96 mRem.
- i. Dose Equivalent Limit
- a. Maximum Permissible Dose Equivalent = 5000 mrem/year (1250/quarter).
- b. Minimum Detectable Dose per Monthly Badge = 1 mrem.
C. Visitors 140 individuals visited the reactor facility during the period 1 July 2023 to 30 June 2024.
None of the visitors received a measurable dose.
IX. LABORATORY SURVEYS The University of Utah Radiation Safety Office conducted monthly surveys of the facility during the reporting period. The studies have not indicated any unusual radiation levels over previous years. The facility retains records of surveys.
X. ENVIRONMENTAL STUDIES Environmental monitoring conducted by the University of Utah Radiation Safety indicated no unusual dose rates in the areas surrounding the Merrill Engineering Building, which houses the UUTR reactor facility.
Prepared by: Andrew Allison Date: 7/31/2024 Reactor Supervisor
Submitted by: Andrew Allison Date: 7/31/2024 UUTR Interim Reactor Director
Utah Nuclear Engineering Program (UNEP) 7