ML20062C059

2018 Annual Report University of California Davis Mcclellan Nuclear Research Center

ML20062C059
Person / Time
Site:	University of California-Davis
Issue date:	03/02/2020
From:	McClellan Nucleaer Research Center, McClellan Nuclear Research Center
To:	Office of Nuclear Reactor Regulation
Tran L, NRR/DANU/UNPL, 415-4103
References
Download: ML20062C059 (23)

Text

2018 ANNUAL REPORT Docket Number 50-607 License Number R-130

UCD/MNRC ANNUAL REPORT FOR 2018

1. Introduction The University of California, Davis, McClellan Nuclear Research Center (MNRC) consists of a research reactor, associated radiography and positioning equipment, and a wide variety of equipment to support broad-based research activities. This MNRC Annual Report is published each year in support of the license provided by the United States Nuclear Regulatory Commission (NRC).

The aforementioned license is for the operation of a steady-state TRIGA' reactor with pulsing and square wave capability.

It is the primary intent of this document to provide information relevant to the safe operation of the UCD/MNRC. A brief description of the MNRC facility and administration is followed by operational events and health physics information concerning this facility during CY 2018.

2. UCD/MNRC Facility Description The UCD/MNRC is located on the McClellan Industrial Park site; the reactor is housed in Building 258. The McClellan Industrial Park site is approximately 2600 acres, located eight miles northeast of Sacramento, California.

The UCD/MNRC facility is a three level 14,720 sq. ft. rectangular-shaped enclosure that surrounds a 2 MW research reactor. The UCD/MNRC provides four neutron beams to four bays for radiography and other research and commercial activities. All four bays are capable of using radiography film techniques, but 3 normally uses electronic imaging devices. Space, shielding and environmental controls are provided by the enclosure for neutron radiography operations performed on a variety of samples. Adequate room has been provided to handle the components in a safe manner.

In addition to the radiography bays, the UCD/MNRC reactor also has several in-core facilities ranging from a pneumatic tube system to a central irradiation facility.

For more detailed information on the UCD/MNRC project, the reader is referred to the UCD/MNRC Safety Analysis Report.

3.0 UCD/MNRC Administration UCD/MNRC Organization. The UCD/MNRC is licensed by the Nuclear Regulatory commission (NRC) to operate under the provisions of operating license R-130.

The University of California Regents have designated the Chancellor at UC Davis to be the license holder. The UCD Chancellor has in-turn delegated the Vice Chancellor for Research to be the licensee of record.

The UCD/MNRC is under the direction of the UCD/MNRC Director.

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UCD/MNRC ANNUAL REPORT FOR 2018 4.0 Facility Modifications (Section 50.59 of 10CFR Part 50), and experiments.

None 5.0 Approved Changes to Experiments None 6.0 Licensing and Regulatory Activities 6.1 NRC Items

a. The Nuclear Regulatory Commission conducted a semi-annual inspection the week of 8 January 2018. No significant findings reported.

b. The Nuclear Regulatory Commission conducted an inspection the week of 27 August 2018. No significant findings reported.

c. Al Adams and Linh Tran visit the facility for meetings and a tour of the facility on 5 September 2018

d. UCD/MNRC submits facility relicensing package to the NRC on 29 June 2018. Timely renewal confirmation received in August from NRC 6.2 Nuclear Safety Committee (UCD/NSC)

a. The Nuclear Safety Committee held its semi-annual meetings on 27 February and 20 August 2018.

b. The Nuclear Safety Committee performed an Operations audit for 2017 on 25 February 2018.

c. The Nuclear Safety Committee performed an audit of the Radiation Safety Program on 30 October 2018.

d. The Nuclear Safety Committee performed a Security audit on 17 December 2018.

7.0 OPERATIONS OPERATING HISTORY:

TOTAL OPERATING HOURS THIS YEAR: 1358.6 TOTAL OPERATING HOURS: 53025.77 TOTAL MEGAWATT HOURS THIS YEAR: 1261.48 TOTAL MEGAWATT HOURS: 67499.65 TOTAL NUMBER OF PULSES PERFORMED THIS YEAR: 0 TOTAL NUMBER OF PULSES PERFORMED: 484 2

UCD/ MNRC Annual Report 2018

UCD/MNRC ANNUAL REPORT FOR 2018 7.1 UNSCHEDULED REACTOR SHUTDOWNS and NOTED PROBLEM AREAS:

In 2018, there were three (3) unscheduled reactor shutdowns at the MNRC reactor facility. The following is a list of the unscheduled shutdowns:

2017 UNSCHEDULED REACTOR SHUTDOWNS Type of Failures Total Number CSC 0 Other 3 TOTAL NUMBER OF UNSCHEDULED SHUTDOWNS IN 2018 3 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec CSC 0 0 0 0 0 0 0 0 0 0 0 0 Other 0 0 0 1 0 0 1 0 0 0 1 0 Notes 1 2 3 Notes:

1. Shim 4 Foot switch.

2. Inadvertent Reactor Room Manual Scram. Operator error.

3: Loss of Exhaust Fan-1 (EF-1). Scrammed the reactor.

January

1. There were no unscheduled shutdowns in the month of January.

2. There was one callback to the facility in January.

a. Spurious fire alarm February

1. There were no unscheduled shutdowns in the month of February.

2. There were no callbacks to the facility in February.

March

1. There were no unscheduled shutdowns in the month of March.

2. There was one callback to the facility in March.

a. Rod Withdrawal Prohibit (RWP) message and a UPS fault probably due to lightning in the area. Both cleared on Acknowledgement(COA)

April

1. There was one unscheduled shutdown in the month of April.

a. Shim 4 foot switch sticking. See Anomaly report below.

2. There were no callbacks to the facility in the month of April.

May

1. There were no unscheduled shutdowns in the month of May.

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UCD/MNRC ANNUAL REPORT FOR 2018

2. There were five (5) callbacks to the facility in the month of May.

a. 4 UPS faults all Cleared on Acknowledgement.

b. One callback was due to a Stack Continuous Air Monitor (CAM)

Fault when the particulate channel card failed.

June

1. There were no unscheduled shutdowns in the month of June.

2. There was one callback to the facility in the month of June.

a. Rod Withdrawal Prohibit. Cleared on acknowledgement.

July

1. There was one unscheduled shutdown in July due to operator error.

2. There were no callbacks to the facility in the month of July.

August

1. There were no unscheduled shutdowns in the month of August.

2. There no callbacks to the facility in the month of August.

September

1. There were no unscheduled shutdowns in the month of September.

2. There was one callback to the facility in the month of September.

a. UPS fault. Cleared on Acknowledgement.

October

1. There were no unscheduled shutdowns in the month of October.

2. There was one callback to the facility in the month of September.

a. Staging Area 4 RAM alarm due to GM tube failure.

November

1. There was one unscheduled shutdown in the month of November.

a. Loss of EF-1. See Anomaly report below.

2. There was one callback to the facility in the month of November.

a. UPS Fault. Cleared on acknowledgement.

December

1. There were no unscheduled shutdowns in December.

2. There were no callbacks to the facility in the month of December.

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UCD/MNRC ANNUAL REPORT FOR 2018

7.2 ANOMALIES

During 2018, there were two anomalies at the MNRC facility and no Radiological Incident Investigations.

7.2.1 Shim 4 Foot Switch Anomaly Report Date: 4/26/2018 Time: 1219 hrs Reactor Status: Operating/Critical leveling power at 50 watts.

After normal reactor operation at 1 MW for 2.22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br />, reactor power was being lowered to 50 watts to set conditions to remove an in-tank experiment. During this reactor power reduction, control rod Shim 4 was lowered enough to activate its rod bottom foot switch which not only stops inward rod motion, but also causes a control rod indication color change (from green to black) on the HiRes monitor in the control room. When the reactor operator attempted to withdraw Shim 4 from that position, the control rod indications on the HiRes monitor did not follow the actual control rod movement nor did the control rod color change back to green. This indicates to the reactor operator that the Shim 4 rod bottom footswitch was stuck.

The reactor was shutdown to investigate.

With the reactor shutdown, Shim 4 was driven out and in several times while the Reactor Supervisor was observing the control rod mechanisms locally. The footswitch assembly operated properly each time and a control rod operability check was performed satisfactorily. Scram time was 0.39 sec.

No repairs or adjustments were made.

7.2.2 EF-1 Fan Motor Anomaly Report Date: November 19, 2018 Time: 1446 hrs Reactor Power Level: Operating normally at 1 MW.

Describe the reactor conditions prior to the anomaly and what occurred during the anomaly:

5 UCD/ MNRC Annual Report 2018

UCD/MNRC ANNUAL REPORT FOR 2018 The reactor was operating normally at 1 MW supporting radiography operations in Bays 1 and 2.

At 1446 hours0.0167 days <br />0.402 hours <br />0.00239 weeks <br />5.50203e-4 months <br /> the EF-1 alarm on the Temperature Control Panel (TCP) sounded and it was observed that the EF-1 fan proof light on the TCP was extinguished.

The loss of EF-1 casualty was announced throughout the facility and the reactor was manually scrammed and Air Conditioning unit 1 (AC-1) was secured from the TCP in accordance with the UCD/MNRC Operating Procedures Table 8.2 Responses to operating alarms.

The Facility Director was notified.

Actions taken to correct the anomaly:

Investigation into the loss of EF-1 began immediately. The mainline fuses (15 amp) were checked satisfactorily (not blown) and the backup circuit breaker (20 amp) was checked and found to be closed and not in the trip free position (i.e. not open).

The EF-1 controller overloads were reset and it appears that these were the cause of the loss of the fan.

After resetting the overloads, EF-1 was restarted and individual phase current readings were taken. Each phase read 4.8 amps with the fan running.

Note: EF-1 has run essentially continuously 24/7/365 for 16 years.

These overloads were installed in the EF-1 controller in 2002 (about 16 years old) and may be degrading.

The loading of the reactor room ventilation filters combined with the age of the overloads may be the cause of this event.

Corrective actions needed to prevent this anomaly from recurring in the future:

The overloads are being evaluated to determine their normal run current and overload ratings.

There is a very high particulate/smoke level in the surrounding environment as a result of the forest and wild fires ongoing in Northern California. The ventilation filters are being excessively loaded with this material and will be changed out once the fires are out or the atmospheric conditions/air quality significantly improves. After the filters are changed out, EF-1 motor running currents will be checked again.

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UCD/MNRC ANNUAL REPORT FOR 2018 7.3 MAINTENANCE OTHER THAN PREVENTIVE:

February System # Description Work Performed 5490 Helium Supply Replace expended Helium Supply bottle March System # Description Work Performed Replaced Rx Room (Normal Path) HEPA filter.

5620 Reactor Ventilation DOP test SAT.

Repaired overheated lug and wire connection for 1001 Reactor CAM Reactor CAM blower motor April System # Description Work Performed Replaced Fuel Temp #1 Action PAK due to erratic 5320 Scram test Circuit indications.

May System # Description Work Performed Replaced Fuel Temp #2 Action PAK and both the 5320 Scram test Circuit K3 and K4 relays.

Replaced failed NPP-1000 (High voltage failure 5330 NPP-1000 when the Rx was shutdown), with the calibrated spare unit.

5490 Helium Supply Replace expended Helium Supply bottle Replaced failed Stack CAM Particulate channel 1001 Stack CAM card.

July System # Description Work Performed Replace failed power switch for the Stack CAM 1001 Stack CAM blower motor.

5490 Helium Supply Replace expended Helium Supply bottle 7

UCD/ MNRC Annual Report 2018

UCD/MNRC ANNUAL REPORT FOR 2018 August

1. MNRC completed the annual reactor maintenance shutdown during the month of August. Technical Specification required periodic maintenance as well as general maintenance was performed.

2. Parametric values noted during testing are as follows:

Control Rod Worth:

Transient Rod: $1.83 Shim 1: $2.61 Shim 2: $2.49 Shim 3: $2.56 Shim 4: $2.91 Regulating Rod: $2.78 Control Rod Scram Drop Times:

Transient Rod: 0.36 sec Shim 1: 0.39 sec Shim 2: 0.37 sec Shim 3: 0.40 sec Shim 4: 0.39 sec Regulating Rod: 0.38 sec Shutdown Margin: $6.17 The normal nuclear instrument calorimetric calibration was performed. Both the NPP channel and the NM-1000 channels of the Nuclear Instruments were satisfactory, and no adjustments were required.

At Power Scram values: NPP-1000: 107% indicated, NM-1000: 105% indicated.

System # Description Work Performed Demineralizer 5120 Replaced all 4 depleted resin bottles System September System # Description Work Performed Replaced burned wire and lug on Rx CAM pump 1001 Reactor CAM switch.

October System # Description Work Performed 5490 Helium Supply Replaced expended helium supply bottle Radiation Replaced failed Staging Area 4 RAM with 1020 Monitoring calibrated spare unit.

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UCD/MNRC ANNUAL REPORT FOR 2018 November System # Description Work Performed Building Replaced F2 filters (due excessive loading from 5630 Ventilation ambient smoke from the Camp fire).

Reactor Room Replaced Rx Room ventilation Prefilter due to 5620 Ventilation smoke loading December System # Description Work Performed 5490 Helium Supply Replaced expended helium supply bottle 7.4 Training January

1. Operations and Radiography personnel completed training on Material Handling, Movement, and storage for Pressure Tanks.

2. Facility personnel completed the second half of the 2017 Emergency Drill.

3. One SRO completed training on several modules on Nuclear Theory

4. One SRO completed a review of Normal, Abnormal, and Emergency Procedures.

5. Hosted and conducted training for the Elk Grove High School (Classroom and Practical Lab training).

6. Hosted and conducted training for the Fairfield High School (Classroom and Practical Lab training).

February

1. One trainee completed training on Building Cranes and Crane Operation.

2. Hosted and conducted training for the Douglas Middle School (Classroom and Practical Lab training.

3. Hosted and conducted training for two STEM Class from Gold River School(Classroom and Practical Lab training).

March

1. Hosted and conducted training for STEM Class from Gold River School(Classroom and Practical Lab training).

April

1. All Facility personnel completed Annual ALARA and annual safety training.

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UCD/MNRC ANNUAL REPORT FOR 2018

2. 4 Senior Reactor Operators completed their Biannual Requalification examination satisfactorily.

3. Hosted and conducted training for UCB NE 104 class (Classroom and NAA experiment).

May

1. One Senior Reactor Operator completed training on several modules on Design and Operating Characteristics.

2. One Senior Reactor Operator completed training on document changes.

3. Conducted training for the UCD Physics class. (Irradiations and Transient Rod worth practical and Alpha T determination).

4. Conducted training and tours for EAOP Classes.

June

1. Two Senior Reactor Operators completed their Biannual Medical Exams.

July

1. MNRC conducted summer school classes for the University COSMOS program.

August

1. All licensed operators successfully completed the Radiation Safety for Operators training.

2. All Senior Reactor Operators completed Fuel and Fuel Handling training.

3. Hosted and conducted training for University of California Davis NSSC group. (Classroom and Practical Lab training)

4. Hosted and conducted training for Sac City College. (Classroom and Practical Lab training)

September

1. Two Senior Reactor Operators completed training on Normal, Abnormal and Emergency Procedures.

2. All Senior Reactor Operators completed the Annual Operators Examination.

October

1. Two senior Reactor Operators completed Nuclear Theory training.

2. Two Senior Reactor Operators completed several modules on Nuclear Theory.

November

1. One Senior Reactor Operator completed training on Normal, Abnormal and Emergency Procedures.

December

1. Two Senior Reactor Operators completed training on Normal, Abnormal and Emergency Procedures.

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UCD/MNRC ANNUAL REPORT FOR 2018 11 UCD/ MNRC Annual Report 2018

UCD/MNRC ANNUAL REPORT FOR 2018 Operating Hours 4500 4000 3500 3000 2500 2000 1500 1000 500 0

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UCD/MNRC ANNUAL REPORT FOR 2018 Unscheduled Reactor Shutdowns 2018 5

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec CSC 0 0 0 0 0 0 0 0 0 0 0 0 Other 0 0 0 1 0 0 1 0 0 0 1 0 2018 Total 0 0 0 1 1 1 2 2 2 2 3 3 2017 Total 0 2 2 2 2 2 2 2 3 3 3 3 Months 13

UCD/MNRC ANNUAL REPORT FOR 2018 Reactor Hours 2018 180 160 140 Monthly Operating and Megawatt Hours 120 100 80 60 40 20 0

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 2017 Op-Hrs 113.45 99.13 107.2 112.69 90.8 69.91 114.75 89.32 90.87 99.28 110.93 68.7 2017 Mw-Hrs 108.75 89.03 101.48 107.13 84.74 67.24 111.45 66.26 84.67 89 104.54 64 2018 Op-Hrs 121.35 98.3 94.03 113.55 127.32 111.88 96.7 111.8 101.17 161.93 132.95 87.89 2018 Mw-Hrs 115.09 93.5 91.41 108.98 112.49 98 87.46 93.71 94.71 156.98 127.26 81.89 14

UCD/MNRC ANNUAL REPORT FOR 2018 Reactor Tank Irradiation Facilities 2018 20 19 18 17 16 Number of Irradiations 15 14 13 12 11 10 9

8 7

6 5

4 3

2 1

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Pneumatic 1 0 0 6 3 0 3 6 0 0 0 0 Silicon Fixture 2 2 0 1 2 2 2 1 0 0 2 0 Central Facility 2 0 1 0 1 2 1 1 1 1 1 1 Argon 0 0 0 0 0 1 0 0 0 0 0 0 Neutron Irradiator 3 4 0 4 19 14 9 3 4 2 4 3 Months 15

UCD/MNRC ANNUAL REPORT FOR 2018 Bay Utilization (Shutter Operations) 2018 400 350 Number of Irradiations 300 250 200 150 100 50 0

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Bay 1 78 107 139 149 134 117 123 107 138 226 338 162 Bay 2 79 116 129 156 129 102 76 137 91 262 176 112 Bay 3 0 0 0 0 0 0 4 0 0 0 0 0 Bay 4 0 0 0 0 8 0 0 0 3 3 2 1 Months 16

UCD/MNRC ANNUAL REPORT FOR 2018 Bay Irradiation Requests Completed 2018 225 200 175 150 Number of Irradiation Requests 125 100 75 50 25 0

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Bay 1 62 89 118 98 113 80 96 82 111 124 214 130 Bay 2 37 38 57 77 59 56 36 75 49 140 98 46 Bay 3 0 0 0 0 1 0 1 0 0 0 0 0 Bay 4 1 0 0 0 1 1 1 0 0 1 1 1 Months 17

UCD/MNRC ANNUAL REPORT FOR 2018 8.0 Radioactive Effluents A summary of the nature and amount of radioactive effluents released or discharged to the environment beyond the effective control of the MNRC, as measured at or prior to the point of such release or discharge, include the following:

8.1 Liquid Effluents No liquid effluents were released during 2018.

8.2 Airborne Effluents Airborne radioactivity discharged during 2018 is tabulated in Table 1 below.

TABLE 1 2018

SUMMARY

OF AIRBORNE EFFLUENTS MONTH TOTAL EST.MAX AVG. FRACTION OF EST. DOSE (2) FRACTION OF TOT. EST. AVERAGE EST. CONC. OF APPLICABLE FROM Ar-41 APPLICABLE QUANTITY CONC. OF QUAN. Ar-41 IN 10CFR20 Ar-41 FOR 10CFR20 OF ACT. PART. ACT.

Ar-41 UNRESTRICTED CONC. LIMIT FOR UNRESTRICTED DOSE IN RELEASED RELEASED AREA (1)(3) UNRESTRICTED AREA (1) CONSTRAINT PART. WITH AREA (1) FOR FORM HALF-LIFE UNRESTRICTED WITH > 8 DAYS AREA (1)(4) HALF-LIFE

>8 DAYS (Ci) (uCi/ml) (%) (mrem) (%) (Ci) (uCi/ml)

JAN 2.44 1.43E-10 1.4% 0.87 8.70% NONE NONE FEB 2.18 1.28E-10 1.3% 0.78 7.78% NONE NONE MAR 2.49 1.46E-10 1.5% 0.89 8.88% NONE NONE APR 2.19 1.28E-10 1.3% 0.78 7.82% NONE NONE MAY 1.71 9.98E-11 1.0% 0.61 6.08% NONE NONE JUN 1.67 9.74E-11 1.0% 0.59 5.93% NONE NONE JUL 1.53 8.94E-11 0.9% 0.54 5.44% NONE NONE AUG 2.15 1.26E-10 1.3% 0.76 7.65% NONE NONE SEP 1.78 1.04E-10 1.0% 0.63 6.31% NONE NONE OCT 3.13 1.83E-10 1.8% 1.11 11.11% NONE NONE NOV 2.16 1.26E-10 1.3% 0.77 7.67% NONE NONE DEC 1.45 8.46E-11 0.8% 0.51 5.15% NONE NONE TOT 24.87 NONE NONE AVG 2.07 1.20 E-10 1.2% 0.74 7.38%

(1) This location is 240 meters downwind which is the point of maximum expected concentration based on the worst case atmospheric conditions (see MNRC SAR Chapter 11).

(2) Based on continuous occupancy and the calculation techniques used in Appendix A of the MNRC SAR (Ar-41 at 2.3E-10 uCi/ml continuous for one year equals 1.4 mrem).

(3) 10CFR20 Limit for concentration is 1E-8 (Appendix B, Table 2);

(4) Constraint for dose is 10 mrem/year [10CFR20.1101(d)]

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UCD/MNRC ANNUAL REPORT FOR 2018 8.3 Solid Waste No solid radioactive waste was shipped this year.

9.0 Radiation Exposure Radiation exposure received by facility operations personnel, facility users, and visitors during 2018 is summarized in Table 2 below.

TABLE 2 2018

SUMMARY

OF PERSONNEL RADIATION EXPOSURES NUMBER OF AVERAGE GREATEST AVERAGE GREATEST INDIVIDUALS TEDE INDIVIDUAL EXTREMITY EXTREMITY PER TEDE (1)

INDIVIDUAL (mrem) (mrem) (mrem)

(mrem)

FACILITY 6 65 149 295 1652 PERSONNEL FACILITY 21 <1.0 2 *

• USERS VISITORS 970 <1.0 2 * *

(1) Only 4 individuals received extremity exposure

• Extremity monitoring was not required.

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UCD/MNRC ANNUAL REPORT FOR 2018 10.0 Radiation Levels and Levels of Contamination Radiation levels and levels of contamination observed during routine surveys performed at the MNRC during 2018 are summarized in Table 3 below.

TABLE 3 2018

SUMMARY

OF RADIATION LEVELS AND CONTAMINATION LEVELS DURING ROUTINE SURVEYS AVERAGE HIGHEST AVERAGE HIGHEST (mrem/hr) (mrem/hr) (dpm/100cm2) (dpm/100cm2)

OFFICE SPACES <0.1 <0.1 <5000(1) <5000(1)

REACTOR CONTROL RM <0.1 <0.1 <5000(1) <5000(1)

RADIOGRAPHY CONTROL RM <0.1 <0.1 <5000(1) <5000(1)

COUNTING LAB <0.1 <0.1 <5000(1) <5000(1)

STAGING AREA <0.1 <0.1 <5000(1) <5000(1)

FACILITY (I/S Fence) <0.1 <0.1 <5000(1) <5000(1)

EQUIPMENT RM 0.41 (4) 134 (5) <800(2) <800(2)

DEMINERALIZER AREA 12(4) 340(5) <800(2) <800(2)

REACTOR RM 2.9(4) 2800(5) <800(2) <800(2)

RADIOGRAPHY BAYS 0.6 (3) 300 <800(2) <800(2)

(1) <5000 dpm/100 cm2 = Less than the lower limit of detection for a scanning survey.

(2) <800 dpm/100 cm2 = Less than the lower limit of detection for a swipe survey.

(3) Due to Bay 1 Storage Areas; all other areas and bays are significantly lower (typically <0.1 mrem/hr).

(4) General area dose rate.

(5) Maximum contact dose rate.

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UCD/MNRC ANNUAL REPORT FOR 2018 11.0 Environmental Surveys Environmental surveys performed outside of the MNRC during 2018 are summarized in Tables 4

& 5 below. The environmental survey program is described in the MNRC Facility Safety Analysis Report.

TABLE 4 2018

SUMMARY

OF ENVIRONMENTAL TLD RESULTS (WITH NATURAL BACKGROUND(1) SUBTRACTED)

AVERAGE HIGHEST (mrem) (mrem)

ON BASE (OFF SITE 1-20 & 64) 7 16 ON SITE (SITES 50 - 61 & 65-71) 12 20 (1) Natural background assumed to be the off base (Sites 27-42) average of 29 mrem.

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UCD/MNRC ANNUAL REPORT FOR 2018 TABLE 5 2018

SUMMARY

OF RADIOACTIVITY IN WELL WATER ALPHA BETA TRITIUM Cs-137 (pCi/l) (pCi/l) (pCi/l) (pCi/l)

AVERAGE <MDA 3.68 <MDA <MDA HIGHEST <MDA 5.91 <MDA <MDA MDA is the minimum detectable activity at the 95% confidence level.

The MDA range for the analyzed radionuclides (pCi/L).

MIN MAX Alpha 1.4 2.53 Beta 0.99 1.72 Tritium 232 266 Cs-137 1.12 1.62 22