ML22273A135

University of California Irvine, Annual Report Submittal in 2021-2022 Accordance with Technical Specification 6.7.1

ML22273A135
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Site:	University of California - Irvine
Issue date:	09/29/2022
From:	University of California - Irvine
To:	Office of Nuclear Reactor Regulation
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UNIVERSITY OF CALIFORNIA IRVINE NUCLEAR REACTOR FACILITY ANNUAL REPORT 2021-2022 FACILITY LICENSE R-116 - DOCKET NUMBER 50-326 A. J. SHAKA l Reactor Director GEORGE MILLER l Reactor Supervisor Emeritus JOHN KEFFER l Reactor Supervisor and Facility Manager

Page 1 of 15 Table of Contents Section 1 Operations, Personnel and Reviews Summary .................................................................................. 2 Section 2 Data Tabulations for the Period July 1st, 2021 to June 30th, 2022 .................................................... 4 Section 3 Inadvertent Scrams, Unplanned Shutdowns, Events at Power........................................................... 5 Section 4 Non-Routine Maintenance and Surveillance and Other Incidents ..................................................... 6 Section 5 Facility Changes and Special Experiments Approved .......................................................................... 7 Section 6 Radioactive Effluent Release............................................................................................................... 8 (a) Gases ......................................................................................................................................................... 8 (b) Liquids and Solids ...................................................................................................................................... 9 Solid, Dry Waste: ........................................................................................................................................ 9 Liquid Waste: ............................................................................................................................................. 9 Section 7 Environmental Surveillance .............................................................................................................. 10 Section 8 Radiation Exposure to Personnel ...................................................................................................... 13 Section 9 Closing Remarks ................................................................................................................................ 15 UC IRVINE NUCLEAR REACTOR FACILITY ANNUAL REPORT l FACILITY LICENSE R-116 - DOCKET NUMBER 50-326

Page 2 of 15 Section 1 Operations, Personnel and Reviews Summary The UCI Reactor Facility has emerged this year from the COVID shutdowns. The reactor has continued to be utilized in training for operator licensing, seen an increase in neutron activation and outside researcher use, and has supported radiation chemistry laboratory courses in the Fall and Spring quarters.

Personnel Reactor Personnel this period have changed and are as follows:

Reactor Director: Professor A. J. Shaka (SRO inactive) replaced Professor Rachel Martin Reactor Supervisor: Mr. John Keffer (SRO) replaced Dr. George Miller (SRO)

Reactor Facility Manager: Mr. John Keffer (SRO)

Associate Reactor Supervisor and Development Engineer: vacated by Dr. Tro Babikian (SRO)

Reactor Operator and Summer Engineer: Mr. Victor Klumper (RO)

Three other students, licensed as ROs in June 2021, have graduated, assumed positions, or continued their graduate studies and are currently in inactive status or will not be operating further at UCI.

Campus Radiation Safety Officer (RSO): Mr. Aldrich Rivera.

Operations The facility has maintained open status for research and instruction and normal operations since th July 6 2021 subject to University of California guidelines for COVID masking and good health practices.

Operation of this facility supported UCI research and education programs in the Department of Chemistry (CHEM) and other UCI schools and departments. Research is being conducted in application of radioisotopes as tracers and radiochemical analytical and separation techniques including applications to nuclear waste separations. A new assistant professor appointed in chemistry is developing plans to use the facility for nuclear fuel related research as her laboratory research program commences. Her laboratory reconstruction has been completed and occupancy began in 2021.

Reactor utilization, apart from operator training and maintenance, is for analytical sample irradiation, production of isotopic tracers, and neutron instrument testing. Analysis samples come from diverse origins related to forensic science, fossil fuels, geochemistry, art, and archaeological studies, chemical separations in nuclear fuel cycle experiments, chemical synthesis, industrial quality control, enzyme studies, trace element pollution studies, etc. Following pandemic closures, laboratory classes were resumed in September 2021 for class work by undergraduates learning tracer and activation analysis techniques using small quantities of short-lived activated materials. In March of 2022, a nuclear instrumentation class with graduates and undergraduates performed laboratory work in the reactor facility and explored a variety of alpha, beta, and gamma spectroscopy techniques and detectors.

UC IRVINE NUCLEAR REACTOR FACILITY ANNUAL REPORT l FACILITY LICENSE R-116 - DOCKET NUMBER 50-326

Page 3 of 15 The operator training program continued with a new class of six participants selected from Chemistry, Physics, and Engineering departments. Lectures resumed by Zoom, and small groups had in-facility hands-on practice sessions. A brief delay in the program has occurred over the Spring quarter following the departure of the staff Development Engineer/Training Coordinator, and for the Summer as several students have been interning at National Labs. Operator training will resume in the Fall, 2022.

Use was made of the facility by other educational institutions, using the reactor and the gamma irradiator, and the tour program of the reactor facility has resumed, attracting visitors from within the University as well as the outside community. A virtual recording was updated and used again this year to provide virtual tours to potential graduate students.

Operations increased over last year, with the reactor generating 30% more energy and the facility receiving over 470 visitors and researchers.

Criticality was achieved for 141.4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, an over 50% increase from the previous year, and the total energy generated was equivalent to 55.2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> at full steady state power. 159 separate experiments were performed this year and 403 samples were irradiated, showing an increased use of the facility, though the pneumatic transfer system use decreased, and its associated Ar-41 release. Fourteen pulses were performed this year, all without incident. A few unusual maintenance/surveillance results/activities were noted/conducted during this period and are described in Section 6.

Inspections and Reviews A routine NRC inspection (encompassing (1) organization and staffing; (2) operations logs and records; (3) requalification training; (4) surveillance and limiting conditions for operation (LCO); (5) emergency planning; (6) maintenance logs and records; and (7) fuel handling logs and records) was conducted December 6-9, 2021. The inspection report dated February 2022 indicated that no findings of significance were identified.

In March 2022, the required annual Reactor Operations Committee meeting was held remotely via Zoom and Google drive. No significant issues were discussed.

An Emergency/Security exercise was conducted on site in March 2022. On and off campus emergency response units were involved. In preparation for this event several Zoom planning meetings were held in late 2021 and early 2022. A full follow-up after action report was prepared by UCI Emergency Service personnel. Nuclear Reactor Facility (NRF) training that discussed roles & responsibilities related to the event was held with EH&S and NRF staff in April 2022.

Inspections/audits continue to be conducted quarterly by the Radiation Safety staff of EH&S at UCI.

These have identified that surveillance frequency schedules have been properly maintained, and results continue to show absence of significant levels of contamination or personnel exposure.

UC IRVINE NUCLEAR REACTOR FACILITY ANNUAL REPORT l FACILITY LICENSE R-116 - DOCKET NUMBER 50-326

Page 4 of 15 Section 2 Data Tabulations for the Period July 1st, 2021 to June 30th, 2022 TABLE I - General Information Experiment Approvals on file (active) 3 Experiments performed (including repeats) 159 Samples irradiated 403 Energy generated this period (Megawatt hours) 13.81 Total, 69 element core 127.00

>74 element core 1718.85 Total energy generated since initial criticality (Megawatt hours) 1845.85 Pulse operation this period 14 Total reactor pulses to 6/30/2022 1114 Hours critical this period 141.4 Total hours critical to date 11001.2 Inadvertent scrams or unplanned shutdowns or events at power 11 Non-research personnel visits to reactor - logged and PRM issued as individuals 284 Maximum dosimeter recorded for visits - all less than (1 mrem) 0.1 Visiting researchers (Temporary PRM, incl. repeats) 187 Maximum exposure recorded at one visit (mrem) 0.2 Staff and researchers badged with Thermoluminescent Dosimeters (TLD) 10 Students and assistant, or operators training - (TLD badged) 19 Exposures reported for radiochemistry class (2021-22), deep mrem ave. 8 Isotope Shipments off campus this period (EH&S took custody of 1 source, on campus) 0 TABLE II - Reactor Core Status 2022-06-30 (Core Configuration last Changed 2018-01-18)

Fuel elements in core (including 2 fuel followers) 84 Fuel elements in storage (reactor tank - used) 23 Fuel elements unused (4 instrumented elements + 1 element + 1 FFCR) 6 Graphite reflector elements in core 32 Graphite reflector elements in reactor tank storage 2 Water filled fuel element positions 4 Experimental facilities in core positions 5 Non-fueled control rods 2 Total core positions accounted for 127 Core excess, cold, no xenon (as of 6/30/2022) $2.72 Control Rod Worths (Calibrated 01/27/2022) REG $2.85 SHIM $3.26 ATR $1.78 FTR $0.67 Total $8.56 Maximum possible pulse insertion (calculated) $2.45 Maximum peak power recorded (4/27/2022), $2.45 insertion 887MW Maximum peak temperature recorded in pulse (B-ring,4/27/2022), $2.45 insertion 411 °C UC IRVINE NUCLEAR REACTOR FACILITY ANNUAL REPORT l FACILITY LICENSE R-116 - DOCKET NUMBER 50-326

Page 5 of 15 Section 3 Inadvertent Scrams, Unplanned Shutdowns, Events at Power TABLE III - Scrams, Unplanned Shutdowns, Events at Power Date Time Power Type and Cause 2021-10-14 <250kW WRLM period scram received during ascension to full power by trainee was attributed to irreproducible electronic noise.

2021-11-14 <1.5W WRM noise with erratic movement of signal to chart recorder and period scram prior to startup for core excess attributed to incomplete spring return of calibration push button.

2022-01-11 WRM scram noise 2021-01-20 200 kw Linear scram from Wide Range Linear Module (WRLM) was triggered as the energy potentiometer was being (gain) adjusted to match the calculated power level for the reactor. Restart authorized by the Reactor Supervisor. Power levels were re-attained at 200 kw and calibration values re-checked. As in prior years.

2022-01-26 <1.5W WRM HV scram on key switch reset 2022-03-09 <1.5W WRM period scram on startup air firing of transient rods 2022-03-17 <1.5W WRM period scram on startup air firing of transient rods 2022-05-10 <1.5W WRM period scram on cell phone interference console 2022-05-18 <1.5W WRM period scram on cell phone interference console 2022-05-31 <1.5W WRM period scram on startup air firing of transient rods 2022-06-27 <1.5W WRM period scram on cell phone interference console UC IRVINE NUCLEAR REACTOR FACILITY ANNUAL REPORT l FACILITY LICENSE R-116 - DOCKET NUMBER 50-326

Page 6 of 15 Section 4 Non-Routine Maintenance and Surveillance and Other Incidents The following non-routine maintenance/surveillance activities were carried out during this period.

As noted earlier, routine surveillance and operations were established as of the start of this review period.

TABLE IV - Maintenance, Surveillance, and Other Incidents Date Time Title and Description 2021-10-21 Fast Transient Rod (FTR) Drive Repair. Dashpot connecting rod thread repair and dashpot piston replacement. Event report made to NRC UCI Project Manager and NRC staff. Event reviewed during NRC Annual Inspection December 2021.

2021-11-25 Reactor Cooling Pump Motor Starter Switch Coil Replacement. A failed (open circuited) pump motor starter switch coil was replaced with an identical P/N coil by UCI electricians.

2021-12-07 Area Radiation Monitor (ARM) Computer System Disk Replacement. The ARM control room computer display monitor failed to update. A failed disk drive was identified as cause by UCI Physical Science IT. The drive was replaced by a second backup disk, and the monitoring software was reinstalled. Continuous Air Monitoring (CAM) remained operational throughout.

2022-01-11 The local ARM ir7040 used to monitor the Pneumatic Transfer system return port was removed from service for repair. It was returned to the factory, repaired, and reinstalled. Currently it is monitoring locally and awaiting control room monitor display upgrades. The other nine ARM detectors are operating normally and remotely monitored in the control room.

2022-04-12 Rowland Hall Ventilation System Outage. The building ventilation system that provides normal and emergency supply and exhaust to the reactor facility shutdown. No reactor operations or sample handling occurred during the outage.

Reactor Ventilation Operability Checklist (VOCL) was completed satisfactorily after building ventilation was restored. Duration of outage was less than one hour.

2022-05-19 Pneumatic Transfer System Sample Tube (rabbit) broken within transfer tube to reactor. All pieces were retrieved from within system and terminus.

2022-06-22 Pneumatic Transfer System Sample Tube (rabbit) broken within transfer tube to reactor. All pieces were retrieved from within system and terminus.

UC IRVINE NUCLEAR REACTOR FACILITY ANNUAL REPORT l FACILITY LICENSE R-116 - DOCKET NUMBER 50-326

Page 7 of 15 Section 5 Facility Changes and Special Experiments Approved Five (5) 10 CFR 50.59 changes were initiated and completed during the course of the year:

2021-01 9/14/2021 Updated Startup and Ventilation Checklists, and Shutdown Checklist.

2021-02 8/24/2021 Installation of a BIRNS LED High Lumens Pool Light.

2021-03 11/4/2021 Installation of BNC connections to REG, SHIM, and ATR Rod Position Indication (RPI) to permit high impedance digital monitoring access to the panel indication signals.

2021-04 11/15/2021 Replace FTR 1/4 dia rod and dash pot piston with like parts and rethread piston connecting rod.

2021-05 11/19/2021 Update SOP 3.3 section 6 Emergency Procedures for lessons learned during emergency exercise held 2/17/2021.

No new experiments involving the reactor were approved or performed during the year.

UC IRVINE NUCLEAR REACTOR FACILITY ANNUAL REPORT l FACILITY LICENSE R-116 - DOCKET NUMBER 50-326

Page 8 of 15 Section 6 Radioactive Effluent Release (a) Gases The major direct release to the environs is Argon-41 produced during normal operations. Very small amounts of other gases may be released from irradiated materials in experiments.

Releases are computed based on original measurements at point of origin within the facility and taking only dilution into account. Since much of the release is from operation of the pneumatic transfer system for samples, this is a conservative estimate in that assumption is made that all use of the PT is at full steady state power level (250 kW) when, in fact, considerable use is with the reactor at a lower power level.

In view of the small numbers involved, and the fact that an integrated dose check is provided by an environmental dosimeter hanging on the side of the exhausts at the point of entry to the fan creating the stack discharge, it is considered unnecessary to provide further checks of these estimates. The dosimeter data confirm that an individual standing directly in the exhaust flow for one year would receive an additional submersion dose from the exhaust less than the reliability limit of the dosimeters, or less than 20 mrem per year. The dosimeter data are presented separately in section 7. Over the years that data have been collected, the accumulated exposure at the exhaust locations have been lower than for "control" points because of lower masses of concrete structures in the vicinity. In fact, the data have been consistent at about 20 mrem per year below control level, and >30 mrem below a distant check level (5th floor library) so confidence of exposure less than 5 mrem over background seems plausible.

Release estimates based on operational parameters are as follows:

TABLE V - Radioactive Effluent Release Estimates Operation of pneumatic transfer system - 07/01/2021 - 06/30/2022:

A. Minutes of Operation (minutes): 185 B. Release Rate Assumed (µCi/mL): 6.0 E-08 C. Flow Rate of Exhaust Air (mL/min): 1.2 E+08 D. Dilution Factor (unitless): 0.01 E. PT System Release Computed (µCi): A*B*C*D = E: 13.32 Release from pool surface - 07/01/2021 - 06/30/2022:

F. Total Hours of Operation at Full Power (EFPH): 55.24 G. Release Rate Assumed (µCi/mL): 1.0 E-08 H. Flow Rate of Exhaust Air (mL/min): 1.2 E+08 I. Dilution Factor (unitless): 0.01 J. Pool Surface Release Computed (µCi): F*G*H*I*60 = J: 39.77 Total Emissions from PT and Pool (µCi): E + J: 53.09 Total Effluent Released in One Year (mL): 525960 min / year*H*I 6.31 E+11 Average Concentration Released (µCi/mL): Total Emissions / Total Effluent 8.4 E-11 Since 2.0 E-09 µCi/mL provides an annual exposure for constant immersion of 10 mrem, this corresponds to < 0.5 mrem potential additional radiation exposure to an individual standing in and breathing in the effluent stack for the entire year, a zero likelihood event.

Additional note: the mixed and diluted exhaust plume is discharged to approximately 100 feet above the roof level (200 feet above surrounding ground), granting even greater dilution.

UC IRVINE NUCLEAR REACTOR FACILITY ANNUAL REPORT l FACILITY LICENSE R-116 - DOCKET NUMBER 50-326

Page 9 of 15 (b) Liquids and Solids Liquid and solid wastes from utilization of by-product materials are disposed through a university contract. Waste is transferred to the custody of UCI Environmental Health and Safety (EH&S). Disposals to this custody are given below. It is important to note that activity values are estimated at the time of transfer to EH&S control. Since few shipments are being made from campus, decay to negligible levels occurs for all medium-lived radionuclides. Teaching course items (used for training in liquid scintillation counting techniques) may be a mixture of reactor generated byproducts including 3H from 6Li irradiation and purchased materials (exclusively 14C). During this period, advantage continued to be taken of a campus program to dispose of additional legacy radioisotope materials including decayed sealed sources and measurement samples, mostly not UCI reactor related.

Production of radioactive waste materials has been minimal during this period.

Solid, Dry Waste:

Two separate solid dry waste transfers were made this period.

1. One container of dry solids, 2 ft3, with 77As (trace amount).

2. One container of dry solids, 1 ft3, with 24Na 1 µCi at time of transfer.

Liquid Waste:

A total of 2 gallons of liquid wastes were transferred during this period.

1. 1 one gallon container of waste from sample disposal following activation analysis containing petroleum distillates Naphtha 100%, 76As, 42K, 110mAg 1 µCi total.

2. 1 one gallon container of waste from sample disposal following activation analysis containing N Methyl Pyrrolidone 100%, 38Cl, 24Na, 42K 1 µCi total.

UC IRVINE NUCLEAR REACTOR FACILITY ANNUAL REPORT l FACILITY LICENSE R-116 - DOCKET NUMBER 50-326

Page 10 of 15 Section 7 Environmental Surveillance Environmental dosimeters are in place at 12 locations around the UCI Campus for environmental monitoring purposes. These are provided by Mirion Technologies, Oak Ridge, TN (formerly in Irvine, CA). The environmental packs have three chips in each pack which are averaged for exposure recording. Mirion runs multiple control samples in addition to the locations listed below. All dosimeters are housed in small metal locked boxes (except for locations 10 and 12). The tables below list the locations. As work in Engineering Tower 521 had ceased, the dosimeter there was redeployed to the storage closet across the hall from the east side of the reactor facility. Other locations have been renamed to agree with the locations in the revised ventilation system provided for Rowland Hall, and a new laboratory constructed on the former loading dock adjacent to the north side of the facility.

Table VII from last year's report (2020-2021) has been updated to include Q1 2021 data that were unavailable when that report was submitted. Last years table is labelled Table VIIa. This years (2021-2022) data are given in Table VIIb.

Routine contamination surveys consisting of wipe tests and G-M surveys have shown mostly a clean facility with significant, removable contamination only in areas coming into direct contact with samples removed from the reactor, and on sample handling tools. Trash is surveyed before disposal and not disposed of unless found to be free of removable and fixed contamination.

Table VI - Locations for Environmental Dosimeters

1. South Reactor Facility Perimeter

2. West Reactor Facility Perimeter

3. North Reactor Facility Perimeter in adjacent lab of Atmospheric Chemistry group.

4. Rowland Hall Roof Air Exhaust Duct to Fan 1.

5. Rowland Hall, First Floor Hallway Over Reactor Facility.

6. McGaugh Hall Top (5th) Floor

7. Langson Library Top Floor

8. Reines Hall Top (5th) Floor

9. Rowland Hall Roof Air Exhaust Duct to Fan 2.

10. On-campus Faculty Housing

11. Rowland Hall Roof Air Exhaust Duct to Fan 3.

12. Reactor Storage Closet Rowland Hall East side of facility.

UC IRVINE NUCLEAR REACTOR FACILITY ANNUAL REPORT l FACILITY LICENSE R-116 - DOCKET NUMBER 50-326

Page 11 of 15 Table VIIa - Environmental Dosimetry Data Average Total Exposures in mrem (Including Control Background)

Quarter Location a 2020 2020 2020 12021 Annual Prior Year Above Control Q2 Q3 Q4 Q1

1. S. Facility Perimeter 16 21 22 31 90 114 +2

2. W. Facility Perimeter 17 23 25 33 98 115 +10

3. N. Facility Perimeter 15 32 22 32 101 123 +13

4. Facility Air Exhaust Fan 1. 11 16 17 26 70 86 -18

5. Hallway Over Facility 12 17 19 27 75 94 -13

6. McGaugh Hall Top Floor 13 19 21 28 81 95 -7

7. Langson Library Top Floor 18 24 27 34 103 122 +15

8. Reines Hall Top Floor 14 20 21 30 85 101 -3

9. Facility Air Exhaust Fan 2. 11 16 18 26 71 86 -17

10. On-Campus Housing 12 18 18 26 74 92 -14 11 Facility Air Exhaust Fan 3. 11 16 17 25 69 87 -19 12 E. Facility Closet 13 18 20 27 78 67 -10 Background Control 15 20 22 31 88 106 0

a. Period not reported 7/23/2021 as prior quarter in 2020 report included approx. 1 month of this period due to COVID-19 issues. Therefore, period above reduced by approx. 1 month.

1. Not available as of 7/23/2021 owing to processing company delays.

UC IRVINE NUCLEAR REACTOR FACILITY ANNUAL REPORT l FACILITY LICENSE R-116 - DOCKET NUMBER 50-326

Page 12 of 15 Table VIIb - Environmental Dosimetry Data Average Total Exposures in mrem (Including Control Background)

Quarter Location 2021 2021 2021 2022 Annual Prior Year Above Control Q2 Q3 Q4 Q1

1. S. Facility Perimeter 25 24 38 24 111 90 +5

2. W. Facility Perimeter 25 24 39 24 112 98 +6

3. N. Facility Perimeter 25 23 40 24 112 101 +6

4. Facility Air Exhaust Fan 1. 18 18 31 19 86 70 -20

5. Hallway Over Facility 21 20 33 20 94 75 -12

6. McGaugh Hall Top Floor 20 21 35 20 96 81 -10

7. Langson Library Top Floor 29 27 43 26 125 103 +19

8. Reines Hall Top Floor 23 23 37 22 105 85 -1

9. Facility Air Exhaust Fan 2. 19 18 31 19 87 71 -19

10. On-Campus Housing 20 20 32 19 91 74 -15 11 Facility Air Exhaust Fan 3. 19 19 31 19 88 69 -18 12 E. Facility Closet 23 21 35 22 101 78 -5 Background Control 24 23 36 23 106 88 0 Notes: Please see updated 2021 Table VIIa provided for completeness due to COVID reporting issues.

Discussion Raw data is presented here, along with controls and prior year comparisons. Within this range, the data sets vary relatively little. Locations on walls bordering the facility, such as 1, 2, 3, are usually the highest, remote locations, such as 10, 11, and 12, are the lowest. Data for this year reflects several issues:

• Location 7 is on the top floor of a large building and may experience greater cosmic flux, as well as concrete releases. This has been a result continuing for many years.

• Location 1 near the facilitys gamma irradiator, as well as a lead cave which continues to store a higher activity load.

• Location 2 is on the other side of a location in the reactor facility temporarily used for source storage.

• Location 3 is on the other side of a concrete wall from the ion exchange resin tanks which have moderate levels of activity. This location is also in a radiation use laboratory, which may be contributing to the higher dose readings but more likely due to TNORM in the concrete wall and floor.

Conclusion Exposure estimated to a single individual in any uncontrolled area at this facility is minimal. With the exception of three locations nearest the facility, all dosimetry associated with exposures from the facility indicates lower than control levels. Locations 1 and 2 are in hallways with extremely minimal occupancy or travel, especially since security policy is to maintain permanently locked doors to the hallways on this floor level (access only with building keys), and location 3 is in an adjacent radiation use laboratory. The hallway overhead (location 5) is only casually occupied and not close to a main building entrance. The air released from the facility/building (measured by locations 4, 9, and 11) continues to give no detectable exposure above background. Over many years, the data at each specific location has shown remarkable consistency.

The net conclusion is that, within precision of measurement, and compared to distant control areas (numbers 7 and 10), we are operating within statistical error of zero of potential (full 24/7 occupancy) public exposure over normal background levels.

UC IRVINE NUCLEAR REACTOR FACILITY ANNUAL REPORT l FACILITY LICENSE R-116 - DOCKET NUMBER 50-326

Page 13 of 15 Section 8 Radiation Exposure to Personnel UCI issues TLD badges to students or researchers regularly utilizing radiation within the facility.

Finger dosimetry (TLD) rings were also issued to all those personnel, as there is a strong likelihood of regularly handling radioactive sources. TLDs were read quarterly by Mirion Technologies, and results are presented in Table VIII. Data are for 4 quarters of operations since April 1, 2021. Reporting categories are deep, eye, shallow, and ring shallow. Neutron dosimetry badging was discontinued owing to absence of any recorded exposure greater than zero after many years. Other individuals visiting or casually working in the facility were issued Personal Radiation Monitors (PRM) DMC 3000s or Dosimans/Dosicards (aka EPDs) for which results are shown in Table IX. 9 persons were issued TLD badges and finger TLDs on a continual basis.

Researchers, operator trainees, and radiochemistry lab students have also been issued TLDs.

Table IX also lists all visiting individuals that were issued with DMC 3000s or Dosimans/Dosicards (PRM) that record in units of 0.1 mrem. In the course of a few hours, a worker could accumulate 0.2 mrem background. A tour visitor usually accumulates 0.0 or 0.1 mrem during a 45 minute visit to the facility.

TABLE VIII Aggregate Personnel Exposure from TLD (mrem) 2021-04-01 to 2022-01-301 Whole Body Ring Group Individuals Deep Eye Shallow Shallow A 3 3 3 20 0 B 3 8 11 13 -

C 4 2 4 3 0 D 19 56 62 67 -

Total 29 77 93 121 0 1

The delays this year were caused by the Supplier closing their Irvine office and operating only out of their Oak Ridge, Tennessee office. The last quarterly report (4Q2021) ended one month later due to the office closure. It covered Oct. 2021- Jan. 2022.

TABLE IX Data from EPDs for Workers and Visitors*

Group Persons Admitted* Max Dose Total Dose (mrem) (mrem)

A 0 0 0 C 187 0.2 0.6 E 284 0.1 1.4 Total 471 2.0

• Multiple admissions of the same individual are separately counted. 311 separate individuals were logged in.

Group A: Activation Analysis Personnel: individuals doing extensive or casual activation analysis and radiochemical work at the facility. Most of the exposure is a result of Cl-38 or Al-28 radioactivity production.

Group B: Workers: individuals receiving exposure as a result of handling isotopes for shipment, and/or sources used for calibration activities in the facility.

UC IRVINE NUCLEAR REACTOR FACILITY ANNUAL REPORT l FACILITY LICENSE R-116 - DOCKET NUMBER 50-326

Page 14 of 15 Group C: Inactive / Other: individuals who did enter but not directly carry out radiation related activities during this period, therefore any exposure reported is an indication of range of general background (for PRM) or background and precision where the TLDs are stored when not in use. This group includes visiting researchers admitted to review facilities for potential experiments, those bringing and taking away samples exposed in the cesium gamma irradiator in the facility and maintenance workers NOT doing work on radiation related systems all of whom are always issued EPD. [Note: Operation of the gamma irradiator is restricted to badged staff personnel].

Group D: Class Students: Radiochemistry Lab (133L) and Operator Training (199/299).

Group E: Tourists: includes tour groups that entered the facility this period.

Personnel exposures continue to be very low at this facility in keeping with ALARA efforts and the low degree of operations experienced. Three individuals performed activation analysis activities this period.

Handling activities of 38Cl and 24Na containing samples leads to some exposure. No radiation exposures received were greater than 25% of that allowed.

UC IRVINE NUCLEAR REACTOR FACILITY ANNUAL REPORT l FACILITY LICENSE R-116 - DOCKET NUMBER 50-326

Page 15 of 15 Section 9 Closing Remarks The facility has seen a recovery in the number of visitors and use for instruction and research from the pandemic restrictions in prior years. Key personnel departure and retirement are being addressed to ensure continued function. Waste generation and disposal has remained at its traditionally low values, given the low power of the reactor and the capacity for short term storage of materials. Radiation exposure to personnel also remains low, attributing most dose absorbed per person to the activation analysis activities of the facility or to handling of calibration sources.

This is a third exceptional year, and future planning remains challenging. The chemistry department has continued to employ a Reactor Facility Manager, who has assumed the role of Reactor Supervisor and Operator Training coordinator. A Reactor Operator summer student has provided operations staff hours following the departure of the full time Assistant Engineer SRO and chemical analyst. The Reactor Director is reactivating his license and supporting increased tours and lab instruction while planning for resumption of operator training in the fall and future faculty research at the reactor.

An Assistant Professor of Chemistry is commencing a radiochemistry and nuclear fuel-oriented research program and is assuming teaching roles within the radiochemistry program, assuring its continuation beyond the recent retirement of the Reactor Supervisor.

It is anticipated that full operations including laboratory classes, tours and research will continue to recover as the campus emerges from the COVID related shutdowns of previous years.

UC IRVINE NUCLEAR REACTOR FACILITY ANNUAL REPORT l FACILITY LICENSE R-116 - DOCKET NUMBER 50-326