ML22084A600

North Carolina State Univ., Annual Operating Report for 2021

ML22084A600
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Site:	North Carolina State University
Issue date:	03/25/2022
From:	North Carolina State University
To:	Office of Nuclear Reactor Regulation
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NORTH CAROLINA STATE UNIVERSITY DEPARTMENT OF NUCLEAR ENGINEERING PULSTAR REACTOR ANNUAL REPORT DOCKET NUMBER 50-297 For the Period: 01 January 2021 - 31 December 2021 The following annual report for 2021 is submitted in accordance with Section 6.7.4 of the North Carolina State University PULSTAR Reactor Technical Specifications:

6.7.4.a Brief Summary:

Reactor operations have been routine during this reporting period.

i Operating experience including a summary of experiments performed.

The reactor facility had a total of 1194 utilization hours in 2021. The utilization hours exceeded critical hours (1043 h) since there are often more than one user of the reactor facility at a given time. The following is a brief summary of the types of experiments performed, including for teaching laboratories, courses, research and service:

• 1/M Approach to criticality

• Control rod worth measurements

• Reactivity parameter measurements

• Core thermal power and coolant temperature measurements

• Axial power and peaking factor measurements (flux mapping)

• Positron annihilation spectroscopy measurements

• Neutron diffraction measurements

• Neutron transmission measurements

• Neutron flux measurements

• Material irradiations and testing

• Neutron detector testing and certification

• Neutron radiographic imaging

• Isotope production

• Neutron activation analysis measurements ii Changes in Performance Characteristics Related to Reactor Safety:

None 1

iii Results of Surveillance, Tests, and Inspections:

The reactor surveillance program has monitored the following trend in reactor systems performance during this reporting period:

An unaccounted loss of primary water that began in 2015 continued through 2021. A repair was made in Oct.

2020 that decreased the leak rate to a low leak rate. Efforts to repair the lower leak rate have been evaluated and are expected to begin in 2022. The concentration of radionuclides detected in the reactor coolant met regulatory limits for release to unrestricted areas (10 CFR 20 Appendix B Table 2).

The electrical systems for the reactor had several issues in 2021. A number of electrical system components, including original plant components, were repaired or replaced as discussed in the maintenance log items below.

No other significant or unexpected trends in reactor systems performance have been identified during this reporting period.

The Reactor Safety and Audit Committee (RSAC) performed its annual audit for the facility and determined that all phases of operation and supporting documents were in compliance.

6.7.4.b Energy Output and Critical Hours:

Total Energy Output in 2021: 39.2 Megawattdays Critical hours in 2021: 1043.6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> Cumulative Total Energy Output Since Initial Criticality: 2139.9 Megawattdays 6.7.4.c Number of Emergency and Unscheduled Shutdowns:

Emergency Shutdowns - NONE Unscheduled Shutdowns - Two 25-OCT-2021 Shutdown due to immediate operator action in Response to Abnormal Conditions. The reactor was operating at 1 MW when the annunciator alarm and SCRAM horn simultaneously sounded, and the annunciator lights all turned off/lost power, without any indications of an abnormal or SCRAM condition. No SCRAM occurred. Following shutdown, maintenance log

1. 868 was opened and troubleshooting of the electrical systems began. A blown fuse was found in the annunciator power supply and was replaced. The following morning, a full startup checklist was completed and all reactor equipment was verified to be operable prior to restarting the reactor.

13-DEC-2021 Manual SCRAM due to receipt of a Low Primary Flow annunciation. While operating at 1 MW, the Low Primary Flow alarm annunciated. The reactor operator followed immediate actions and performed a manual SCRAM. The operator and Designated Senior Reactor Operator observed a normal flow rate of 500 gpm on the primary flow channel meter despite the annunciator sounding. Maintenance log ML #871 was opened. Troubleshooting investigation of the false annunciation determined that relay #C-03 had high resistance across the contacts, effecting the initiation of a low flow scram annunciation. This relay was subsequently replaced. Upon completion of the investigation, a full startup checklist was completed, the reactor was authorized for restart, and the reactor was returned to normal operations.

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6.7.4.d Corrective and Preventative Maintenance:

Preventative maintenance, tests and calibrations are scheduled, performed and tracked utilizing the PULSTAR Surveillance File System. Each major component of the Reactor Safety System defined in Section 3.3, and all surveillance required by Section 4 of the Technical Specifications are monitored by this file system to ensure that maintenance and calibrations are performed in a timely manner. All historical data relating to those components, in addition to many other sub-systems, are maintained in these files. Any reactor equipment or components requiring corrective or preventative maintenance are tracked in the Maintenance Log (ML) file.

Maintenance Log items tracked during 2021 are listed below.

ML#859 PS-4-06 Pool Liner - A leak site was detected located on the lower west wall of the pool liner in October 2020. The design of a full repair for the west wall leak site is in process. Efforts to repair the leak have been evaluated and are expected to begin in 2022.

ML#861 PS-1-11 Temperature Monitoring Channel - During the 6 month calibration performed on 09 Mar 2021, the second (redundant) temperature switch did not pass calibration. Subsequent inspection revealed that there was water present in the switch housing. The water was drained and the switch was dried out. The required Thermal Switch calibration was subsequently completed satisfactorily. A spare switch was ordered. During the 6 month calibration on 07 Sep 2021, the spare switch passed the calibration.

ML#862 PS-3-03 Primary Resin Change - The resistivity in the primary system had been trending lower than 1Mcm but greater than 500kcm, indicating that the primary demineralizer resin needed to be replaced. The resin and the pre/post filters in the primary demineralizer loop were replaced on 5 April 2021.

ML#863 PS-1-06 Source Range (Retired from Service) - During the performance of the Startup Checklist on 19 Apr 20, the Startup Channel fission chamber detector housing flooded due to the N2 pressure hose becoming disconnected from the detector housing tube below the pool water line.

After a period of troubleshooting to try to repair the channel, the Source Channel was removed from service on 04 May 2021.

ML#864 PS-1-07 Neutron Flux Monitoring System - During the initial commissioning of the NFMS SN-001 on 25 May 2021, the channel indicated higher noise on the SR indication than expected. A vendor technician was on site for the commissioning and found a screw that held the HV power supply to the chassis wall wasnt properly insulated contributing to higher noise on the channel.

Additional sources of electronic noise were investigated in the period from 5/26 - 6/29/2021, including the Jamesbury Actuators discussed in ML#865. Subsequently, the NFMS (SN 001) detector cable at the reactor bridge was determined to have an intermittent shielding break causing noise when moved, so NFMS SN-001 was taken offline for repair on 02 July 2021.

ML#865 PS-5-01-1A - Jamesbury Actuators (Isoprobe Valve Actuators) - During commissioning and troubleshooting of the NFMS channel, it was determined that the Jamesbury Actuators - which select which isoprobe is sampling the air for the stack sampling system - were causing noise to feedback to the Control Room Distribution Panel (CB 9) and contributing to additional noise on the NFMS. The Jamesbury Actuators were subsequently replaced on 28 June 2021 with equivalent replacements supplied by FCX Performance.

ML#866 West 02 Monitor - On 05 August 2021 during the performance of the Startup Checklist, the West Wall (MER) Oxygen monitor was found to have a failed power supply. This instrument supports the UCN experiment which is not currently operating. The oxygen monitor is offline for repair.

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ML#867 PS-2-01-1B - Air Compressor - The Experimental Air Compressor stopped operating on 25 Aug 21, AIRMAC Inc. was contacted and motor starter was replaced and the oil was changed. The air compressor was returned to service.

ML#868 PS-1-14-7 -Annunciator Power Supply - On 25 October 2021 the reactor was operating at 1 MW when the annunciator alarm and SCRAM horn simultaneously sounded, and the annunciator lights all turned off/lost power, without any indications of an abnormal or SCRAM condition. No SCRAM occurred. A blown 250V- 7A fuse was found in the annunciator power supply and was replaced, restoring power to the annunciators. The reactor remained shutdown for overnight evaluation.

The next day, a startup checklist was completed proper operation of the reactor console and annunciators were verified.

ML#869 PS-1-14-6, PS-1-07 Control Room Distribution Panel - On Sat. 20 Nov 2021 while the facility was shutdown and secured, Low Pool Water Level and Building Evacuation alarm text messages were received by the reactor staff. The staff responded and found that the Reactor Console UPS had failed, causing the instruments to lose power and fail-safe - no actual alarm condition existed and on-site power was never lost. Electricians were subsequently contracted to assist in troubleshooting the cause. They determined that a faulty neutral connection in the Control Room Distribution panel existed which may have contributed to the failure of the UPS. Repairs were made to the neutral connection and the Reactor Console UPS was replaced with a functionally equivalent UPS. All equipment and console instrumentation fed from the control room distribution panel was evaluated and found to be operating satisfactorily. The monthly generator and confinement fan test was performed satisfactorily. Normal reactor operations resumed on 29 November 2021.

ML#870 PS-1-14-6, PS-1-14 Annunciator Acknowledge Pushbutton - During the startup checklist on 03 Dec 21, the Acknowledge Push Button wouldnt clear (failed to reset) when pressed. The Source Range Inhibit and Linear Reverse annunciators consequently would not clear. It was determined that the Acknowledge Push Buttons normally closed-to-common contacts had shorted causing the reset switch to fail to reset the annunciators. The switch was replaced, testing of the new switch was performed satisfactorily, and a startup checklist was performed satisfactorily.

ML#871 PS-1-14-6, PS-1-14 Annunciator (Low Flow Scram) - On 13 December 2021 while the reactor was operating, the reactor operator received a Low Primary Flow SCRAM annunciation. The operator immediately checked the Primary Flow channel indication and the actual primary flow rate was 500 gpm. The RO then manually scrammed the reactor. The primary flow rate SCRAMs were then checked by decreasing and increasing the primary flow to verify the SCRAM setpoints were operating properly. The Primary Flow SCRAM setpoint checks and functional tests were completed satisfactorily. A 24 VAC relay in the circuit that causes the Low Flow annunciator to initiate was found to have high contact resistance so was replaced. Subsequent surveillance checks and a startup checklist were performed and completed Satisfactorily.

ML#872 PS-1-14 Console UPS + Radiation Monitoring UPS - The Reactor Console and Radiation UPS were both replaced on 15 Dec 21 with new, functionally equivalent Eaton model number 9SX 3000 UPS.

ML#873 PS-1-14 Reactor Console Relays + Terminal Board - Preventive Maintenance was performed from 15 Dec 21 to 22 Dec 21. All the console terminal board screw connections were checked to insure they were tight and the wires were secure. Thirty five original 24 VAC console relays were replaced with new functionally equivalent KHAU-17A11-24 relays. As the relays were replaced, the functionality of each relay circuit was verified to be correct and operational.

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ML#874 PS-1-14 Power Conditioning Transformer - On 17 Dec 21, the Power Conditioning Transformer was replaced by electricians. The old transformer was still working properly but due to the age, it was determined it would be good maintenance practice to replace it. The replacement was a same model SOLA HD Transformer.

6.7.4.e Changes in Facility, Procedures, Tests, and Experiments:

Design changes to the facility, procedure changes, changes in tests and experiments, and other changes are tracked utilizing a Control Number (CN) indexing system. Changes tracked during 2021 are listed below.

Facility Changes Design changes to the reactor facility are reviewed to determine whether or not a 10 CFR Part 50.59 evaluation is required. Evaluations were performed for all design changes. Based on the screening reviews performed, all of the changes listed below required a full 10 CFR 50.59 evaluation. Design changes are tracked by Control Number (CN) as listed below.

CN#859 Commissioning of Neutron Flux Monitoring System (NFMS) as the Startup Power Level Channel, 5/21/2021 - On 05 May 2021, a new Thermo Gamma-Metrics NFMS (SN-001) with signal cable and fission chamber detector was approved to be installed and integrated into the reactor console control logic system, as a functional equivalent to replace the Source Range Monitor (SRM) channel which was decommissioned. A 10CFR50.59 evaluation was performed, and no changes to TS, license amendment, or NRC approval were determined to be required. The new NFMS and fission chamber detector met the TS requirements 3.3(a) for the Startup Power Level Channel. The NFMS fission chamber was located with the other nuclear instrument detectors outside the reactor grid plate. Commissioning activities were performed in the period from 04 May 2021 through 02 July 2021 when NFMS SN-001 was taken offline for repair. Reference Maintenance Log MF#864.

CN#864 Changes to Startup Power Level Channel Instrumentation and Configuration - On 26 July 2021, a new Thermo Gamma-Metrics NFMS (SN-002) with signal cable and fission chamber detector was approved to be installed and integrated into the reactor console control logic system as a functional equivalent to replace the NFMS SN-001 channel which was taken out of service for repair. Modifications to the detector mounting bracket, and the NFMS Log Wide Range amplifier circuit gain resistors were also approved. A 10CFR50.59 evaluation was performed, and no changes to TS, license amendment, or NRC approval were determined to be required. The new NFMS and fission chamber detector met the TS requirements 3.3(a) for the Startup Power Level Channel. Commissioning activities were performed in the period from 13 July 2021 through 04 August 2021 when NFMS SN-002 was successfully placed in service as the new Startup Power Level Channel.

Test and Experiments Tests and experiments are reviewed to determine whether or not a 10 CFR Part 50.59 evaluation is required.

No new test or experiment reviews were performed during this period.

Document Changes Procedure changes and minor changes are reviewed to determine whether or not a 10 CFR Part 50.59 evaluation is required. Based on the screening reviews performed, many of the changes listed below required full 10 CFR 50.59 evaluations, however no changes to TS, license amendments, or NRC approvals were determined to be required. Procedure changes are tracked by Control Number (CN) as listed below.

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CN#858 PS 6-12-6 Test and Inspection of the Stack Sample System. Procedure change adding sampling capability and providing instructions for testing of the sample flow rate meter and sampling flow switch. A 10CFR50.59 evaluation was not required. Approved on 26 March 2021.

CN#860 OP-101 Reactor Startup and Shutdown. Procedure change to incorporate the functional changes made to the Startup Channel as approved under Design Change #859. A 10CFR50.59 evaluation was performed, and no changes to TS, license amendment, or NRC approval were determined to be required. Approved on 24 May 2021.

CN#861 OP-103 Reactor Operation. Procedure change to incorporate the functional changes made to the Startup Channel as approved under Design Change #859. A 10CFR50.59 evaluation was performed, and no changes to TS, license amendment, or NRC approval were determined to be required. Approved on 24 May 2021.

CN#862 PS-1-07:S1 Neutron Flux Monitoring System Calibration. New procedure to provide a calibration procedure for the Neutron Flux Monitoring System as approved under Design Change #859. A 10CFR50.59 evaluation was performed, and no changes to TS, license amendment, or NRC approval were determined to be required. Approved on 24 May 2021.

CN#863 OP-105 Response to SCRAMS, Alarms, and Abnormal Conditions. Minor procedure change to the to incorporate the changes made to the Startup Channel as approved under Design Change #859.

A 10CFR50.59 evaluation was not required. Approved on 24 May 2021.

CN#865 OP-101 Reactor Startup and Shutdown. Procedure change to incorporate the functional changes made to the Startup Channel as approved under Design Change #864. A 10CFR50.59 evaluation was performed, and no changes to TS, license amendment, or NRC approval were determined to be required. Approved on 30 July 2021.

CN#866 OP-103 Reactor Operation. Procedure change to incorporate the functional changes made to the Startup Channel as approved under Design Change #864. A 10CFR50.59 evaluation was performed, and no changes to TS, license amendment, or NRC approval were determined to be required. Approved on 30 July 2021.

CN#867 PS-1-07:S1 Neutron Flux Monitoring System Calibration. Procedure change to provide a revised calibration procedure for the Neutron Flux Monitoring System as approved under Design Change

1. 864. A 10CFR50.59 evaluation was performed, and no changes to TS, license amendment, or NRC approval were determined to be required. Approved on 30 July 2021.

CN#868 OP-101 Reactor Startup and Shutdown. Procedure change to update NFMS Startup Channel checkout acceptance criteria per vendor updates, and provide several procedural clarifications. A 10CFR50.59 evaluation was performed, and no changes to TS, license amendment, or NRC approval were determined to be required. Approved on 15 December 2021.

CN#869 PS-1-07:S1 Neutron Flux Monitoring System Calibration. Procedure change to provide a revised calibration procedure for the Neutron Flux Monitoring System per vendor updates. A 10CFR50.59 evaluation was performed, and no changes to TS, license amendment, or NRC approval were determined to be required. Approved on 15 December 2021.

Other Changes License Renewal Documentation:

A Response to a Request for Additional Information RE: License Renewal Application for Facility Operating License No. R-120 for the North Carolina State University PULSTAR Research Reactor (EPID No. L-2020-NFR-0007; Environmental RAI); dated September 21, 2021 was submitted on November 30, 2021.

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Other Items None.

6.7.4.f Radioactive Effluent:

Liquid Waste (summarized by quarters)

i. Radioactivity Released During the Reporting Period:

Releases to the sanitary sewer are given below:

Period (1) (2) (3) (4)1 (5)

Total Number of Total Diluent Tritium 2021 Volume Batches µCi Liters µCi Liters 01 JAN - 31 MAR 3 115 9,841 18,884 112 01 APR - 30 JUN 2 50 6,620 2,670 49 01 JUL - 30 SEP 7 229 23,013 0 227 01 OCT - 31 DEC 3 156 9,955 20,042 154 2021 542 µCi of tritium was released during this year.

2021 550 µCi of total activity was released during this year.

1 Based on gross beta activity only. Tritium did not require further dilution.

ii. Identification of Fission and Activation Products:

The gross beta-gamma activity of the batches in (i) above were less than 2x10-5 Ci/ml. Isotopic analyses of these batches indicated low levels of typical corrosion and activation products. No fission products were detected.

iii. Disposition of Liquid Effluent not Releasable to Sanitary Sewer System:

All liquid effluent met the requirements of 10 CFR Part 20 for release to the sanitary sewer.

iv. Releases to Unrestricted Areas:

In 2021 an unaccounted loss of water from the reactor coolant system occurred. The RCS water loss is measured every work day and occurred at variable rates over the year. RCS water was not observed in surface locations or storm sewer locations outside the reactor building. Therefore the unaccounted RCS water was assumed to be continuously released to grounds beneath the surface on the reactor site at the measured RCS loss rates over the year. Reactor coolant activity and volume assumed to be released to unrestricted areas are given below for 2021:

Total Tritium Volume Period in 2021

µCi µCi Liters 01 JAN - 31 MAR 1,998 1,972 22,892 1 APR - 30 JUN 2,025 2,019 22,310 1 JUL - 30 SEP 1,889 1,872 23,119 1 OCT - 31 DEC 2,530 2,512 23,400 CALENDAR YEAR TOTAL 8,442 8,375 91,721 7

The concentration of radionuclides detected in the reactor coolant met regulatory limits for release to unrestricted areas (10 CFR 20 Appendix B Table 2). Detected radionuclides in reactor coolant were tritium and activation products. Fission products were not detected. Refer to Section 6.7.4.i for environmental water sample results Gaseous Waste (summarized monthly)

i. Radioactivity Discharged During the Reporting Period (in Curies) for:

(1) Gases:

Total Time Year Month Curies Hours JANUARY 744 0.805 FEBRUARY 672 0.226 MARCH 744 0.882 APRIL 720 0.407 MAY 744 0 JUNE 720 0 2021 JULY 744 0 AUGUST 744 0.640 SEPTEMBER 720 0.570 OCTOBER 744 0.631 NOVEMBER 720 0.557 DECEMBER 744 0.290 TOTAL 8760 5.008 (2) Particulates with a half-life of greater than eight days:

Particulate filters from the Stack Particulate Monitoring Channel were analyzed upon removal. There was no particulate activity with a half-life greater than 8 days detected.

ii. Gases and Particulates Discharged During the Reporting Period:

(1) Gases:

Total activity of Argon-41 released was 5.008 Curies in 2021.

The yearly average concentration of Argon-41 released from the PULSTAR reactor facility exhaust stack in 2021 was 2.4x10-8 Ci/ml. Dose calculations for the year were performed using methods given in the Final Safety Analysis Report and gave results less than the 10 CFR Part 20 air effluent dose constraint level of 10 mrem. These results are consistent with environmental monitoring data given in Attachment A.

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(2) Particulates:

Refer to gaseous waste i.(2) above. No activation or fission products were detected.

Solid Waste from Reactor

i. Total Volume of Solid Waste Packaged Total volume of solid waste was 49 ft3.

ii. Total Activity Involved Total activity for solid waste was 1.283 mCi.

iii. Dates of shipments and disposal Transfer of solid radioactive waste to the university broad scope radioactive materials license was made in February, July, August, and September 2021. The University Environmental Health and Safety Center arranges disposal of hazardous wastes.

6.7.4.g Personnel Radiation Exposure Report:

Twenty -six individuals were monitored for external radiation dose during the reporting period. Internal dose monitoring was not required for any individual. Collective deep dose-equivalent was 1.854 person-rem.

Individual deep dose-equivalent ranged from 0.000 rem to 0.697 rem with an average of 0.071 rem. One individual was above 0.250 rem.

6.7.4.h Summary of Radiation and Contamination Surveys Within the Facility:

Radiation and contamination surveys performed within the facility indicated that:

• Radiation in the majority of areas was 5 mrem/h or less.

• Radiation in the remaining areas was higher due to reactor operations.

• Contamination in most areas was not detectable. When contamination was detected, the area or item was confined or decontaminated.

6.7.4.i Description of Environmental Surveys Outside of the Facility:

Radiation surveys performed in unrestricted areas near the reactor facility indicated that:

• Radiation was at background levels for most areas (background is approximately 10 µrem/h).

• Contamination was not detectable.

• Net radiation readings ranged from 0 to 30 µrem/h while the reactor was operating at power.

Radiation was at background levels in all routinely occupied spaces.

• Water samples from Rocky Branch Creek and and two on-site ground water monitoring wells, MW-1 and MW-2, were analyzed in 2021 for tritium, gross beta activity, and gamma emitting radioactivity.

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A new groundwater monitoring well, MW-2, was installed inside the reactor building in Jan 2021.

MW-2 is located approximately 10 feet from the outside of the reactor shield inside the reactor building in the Southeast direction. An existing groundwater monitoring well, MW-1, is located outside the reactor building in the southwest direction.

Samples and analyses results are given below for MW-1 and MW-2.

• Results for external dosimetry in surrounding buildings, environmental air samples, water samples from Rocky Branch Creek, and vegetation and milk samples are given in in Attachment A.

2021 results for MW-1 and MW-2 water samples are given below for tritium, gross beta, and gross alpha analyses:

• All gross beta concentrations were below the detection limit (MDA) for all MW-1 and MW-2 samples.

The Minimum Detectable Activity (MDA) was less 20 percent of the environmental gross beta activity limit of 5x10-8 µCi/ml.

• The tritium concentration in MW-1 water was below the MDA. The MDA was approximately 4 percent of the environmental limit of 2x10-5 µCi/ml.

• The Tritium concentration in MW-2 water was above the MDA for some samples and averaged 1x10-6

µCi/ml for results with detectable activity. The maximum tritium concentration was 1.5x10-6 µCi/ml, which is less than 8 percent of the environmental limit of 2x10-5 µCi/ml.

Sample Date Tritium Tritium Tritium Gross Beta Gross Alpha Units Error MDA MDA MDA MW1 6-Jan-21 6.6E-07 5.2E-07 8.4E-07 8.5E-09 2.0E-10 µCi/ml MW1 9-Apr-21 2.1E-07 2.8E-07 4.6E-07 8.3E-09 (a) µCi/ml MW1 15-Jul-21 -4.3E-07 2.8E-07 4.9E-07 8.4E-09 1.7E-10 µCi/ml MW1 4 Oct-21 -7.9E-07 2.8E-07 4.9E-07 8.5E-09 1.8E-10 µCi/ml MW2 21-Jan-21 1.5E-06 2.0E-07 3.2E-07 8.2E-09 (a) µCi/ml MW2 2-Feb-21 -2.3E-06 4.2E-07 7.6E-07 8.5E-09 (a) µCi/ml MW2 15-Mar-21 0.0E+00 2.1E-07 3.5E-07 8.1E-09 1.8E-10 µCi/ml MW2 14-Apr-21 9.5E-07 2.0E-07 3.1E-07 8.3E-09 (a) µCi/ml MW2 12-May-21 1.2E-06 4.7E-07 7.4E-07 8.3E-09 (a) µCi/ml MW2 9-Jun-21 1.1E-06 3.1E-07 4.9E-07 8.2E-09 1.7E-10 µCi/ml MW2 15-Jul-21 5.0E-07 3.0E-07 4.9E-07 8.2E-09 1.7E-10 µCi/ml MW2 23-Aug-21 7.0E-07 2.1E-07 3.4E-07 8.5E-09 1.9E-10 µCi/ml MW2 15-Sep-21 2.0E-07 2.9E-07 4.9E-07 8.5E-09 1.7E-10 µCi/ml MW2 4- Oct-21 6.6E-08 3.0E-07 4.9E-07 8.5E-09 1.8E-10 µCi/ml MW-2 17-Nov-21 -3.0E-07 2.9E-07 4.9E-07 5.3E-09(b) (a) µCi/ml MW-2 15-Dec-21 2.0E-07 2.1E-07 3.5E-07 9.0E-09 (a) µCi/ml (a) Gross alpha activity was not detected in RCS samples taken monthly. The gross alpha detection limit was < 4x10-10 µCi/ml. If measured, any gross alpha activity detected for MW-1 and MW-2 are assumed to be from natural activity rather than the RCS.

(b) 17-Nov-21 MW2 sample had a gross beta activity of 1.1x10-8Cu/ml due to K-40 and Pb/Bi-214 as identified by gamma spectroscopy. No activation products from reactor coolant were detected by gamma spectroscopy. Gross beta activity was counted for a longer time giving a lower MDA.

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Gamma Spectroscopy Analysis:

No activity above background was detected for water samples taken from MW-1 or MW-2. MDA for common activation products from reactor operation are listed below. At MDA levels, the Effluent Concentration (EC) fraction for each radionuclide was less than 0.02. Radionuclide specific EC are listed in 10 CFR Part 20 Appendix B Table 2 Column 2.

MW-1 Gamma Spectroscopy MDA for 2021 Nuclide Jan Apr Jul Oct Units Sb-124 2.1E-8 2.0E-8 2.1E-8 2.0E-8 µCi/ml Ag-110m 2.3E-8 2.2E-8 2.3E-8 2.1E-8 µCi/ml Co-58 2.2E-8 2.2E-8 2.2E-8 2.1E-8 µCi/ml Mn-54 2.3E-8 2.2E-8 2.3E-8 2.1E-8 µCi/ml Fe-59 4.1E-8 4.0E-8 4.1E-8 3.8E-8 µCi/ml Zn-65 4.0E-8 3.7E-8 4.0E-8 4.0E-8 µCi/ml Co-60 1.3E-8 1.3E-8 1.3E-8 1.2E-8 µCi/ml MW-2 Gamma Spectroscopy MDA for 2021 Nuclide Jan Mar Jun Jul Aug Sep Oct Nov Dec Units Sb-124 1.3E-8 2.1E-8 2.1E-8 2.1E-8 3.1E-8 2.0E-8 2.2E-8 7.3E-8 2.1E-8 µCi/ml Ag-110m 1.5E-8 2.2E-8 2.2E-8 2.2E-8 3.4E-8 2.2E-8 2.2E-8 7.8E-8 3.2E-8 µCi/ml Co-58 1.6E-8 2.2E-8 2.2E-8 2.2E-8 3.3E-8 2.2E-8 2.2E-8 7.8E-8 2.2E-8 µCi/ml Mn-54 1.1E-8 1.6E-8 2.2E-8 2.2E-8 3.5E-8 2.2E-8 2.1E-8 7.8E-8 2.2E-8 µCi/ml Fe-59 2.9E-8 4.1E-8 4.2E-8 4.0E-8 6.1E-8 4.0E-8 3.9E-8 1.4E-7 4.1E-8 µCi/ml Zn-65 3.0E-8 3.9E-8 3.9E-8 3.9E-8 5.9E-8 3.9E-8 4.0E-8 1.7E-7 3.9E-8 µCi/ml Co-60 1.6E-8 1.4E-8 1.4E-8 1.3E-8 1.9E-8 1.3E-8 1.3E-8 4.9E-8 1.3E-8 µCi/ml MW-2 Soil Sediment from MW-2 ground water and soil samples were taken at 5 foot increments during the installation of MW-2 on January 22, 2021. Gamma spectral analysis was performed on these samples. No activity above background was detected.

The MDA for common activation products from reactor operation are listed below. At MDA levels, the Effluent Concentration (EC) fraction was less than 0.1. Radionuclide specific EC are listed in 10 CFR Part 20 Appendix B Table 2 Column 2.

0-5 ft 5-10 ft 10-15 ft 15-20 ft 20-25 ft Units Nuclide Soil Soil Soil Soil Soil Sb-124 6.4E-8 7.3E-8 4.5E-8 5.5E-8 6.0E-8 µCi/g Ag-110m 5.3E-8 6.1E-8 6.0E-8 6.7E-8 7.0E-8 µCi/g Co-58 4.8E-8 6.8E-8 6.8E-8 5.3E-8 7.3E-8 µCi/g Mn-54 6.4E-8 1.2E-7 6.0E-8 5.4E-8 7.5E-8 µCi/g Fe-59 8.4E-7 1.3E-7 1.2E-7 1.2E-7 1.8E-7 µCi/g Zn-65 1.0E-7 1.4E-7 9.2E-8 1.3E-7 2.1E-8 µCi/g Co-60 6.0E-8 9.2E-8 6.4E-8 7.1E-8 9.0E-8 µCi/g 11

ATTACHMENT A PULSTAR REACTOR ENVIRONMENTAL RADIATION SURVEILLANCE REPORT FOR THE PERIOD JANUARY 1, 2021 - DECEMBER 31, 2021 NORTH CAROLINA STATE UNIVERSITY ENVIRONMENTAL HEALTH AND SAFETY CENTER RADIATION SAFETY by Ralton J. Harris and Amy Orders Environmental Health Physicist, Radiation Safety Officer

TABLE OF CONTENTS PAGE NO.

1. INTRODUCTION 1 Table 1 Environmental Monitoring Programs for the PULSTAR Reactor 2

2. AIR MONITORING 3 Table 2.1 Location of Air Monitoring Stations 3 Table 2.2 Airborne Gross Beta Activities 3 Table 2.3 Airborne Gamma Activities (LLD Values) 4 Table 2.4 Regulatory Limits, Alert Levels and Background Levels for Airborne Radioactivity 5

3. MILK Table 3.1 I-131 in Cows Milk 6

4. SURFACE WATER Table 4.1 Gross Alpha and Beta Activity in Surface Water 7 Table 4.2 LLD Values for Gamma Emitters in Surface Water 8

5. VEGETATION Table 5.1 Gross Beta Activity in Campus Vegetation 9 Table 5.2 LLD Values for Gamma Emitters in Vegetation 9

6. OPTICALLY STIMULATED DOSIMETERS 10 Table 6.1 Environmental Dosimeter Doses 10

7. QUALITY CONTROL INTERCOMPARISON PROGRAM 11 Tables 7.1a & 7.1b 12 -13

8. CONCLUSIONS 14

1. INTRODUCTION The Environmental Radiation Surveillance Program exists to provide routine measurements of the university environment surrounding the PULSTAR Reactor.

The specific objectives of this program include:

1) Providing information that assesses the adequacy of the protection of the university community and the public-at-large;

2) Meeting requirements of regulatory agencies;

3) Verifying radionuclide containment in the reactor facility;

4) Meeting legal liability obligations; and

5) Providing public assurance and acceptance.

1 Table 1 Environmental Monitoring Programs for the PULSTAR Reactor at North Carolina State University Sample Activity Conducted Previous Current Basis For Measured By Frequency Frequency Measurement Stack Gross N.E. Continuous Continuous 10 CFR 20 Gases Gamma T.S. 6.7.4 Stack Gross Beta N.E. Monthly Monthly 10 CFR 20 Particles Gamma N.E. T.S. 6.7.4 Emitters Water from Gross Beta N.E. Prior to Prior to 10 CFR 20 Reactor Gross N.E. Discharge Discharge T.S. 6.7.4 Facility Gamma N.E. (~ Monthly) (~ Monthly) City of Tritium Raleigh Ordinance Air Particles Gross Beta RSD Weekly Quarterly 10 CFR 20 at 4 Gamma RSD Weekly Quarterly 10 CFR 20 Campus Emitters Stations*

Air Dose at OSD RSD Quarterly Quarterly 10 CFR 20 7 Campus Dosimeter Stations+

Surface Gross Beta RSD Quarterly Quarterly NCSU Water Gamma RSD Quarterly Quarterly NCSU Rocky Emitters Branch Creek Tritium N.E. --------------- Quarterly 10 CFR 20 Vegetation Gross Beta RSD Semi- Every Other NCSU NCSU Gamma RSD annually Year NCSU Campus Milk I-131 RSD Monthly Every Other NCSU Local Dairy Year Abbreviations Used in Table:

N.E. = Nuclear Engineering/Reactor Facility; RSD = Radiation Safety Division.

• These 4 stations include:

Withers, Lampe, Polk and the Environmental Health & Safety Center (EHS).

+These 7 stations include: PULSTAR Reactor and the 4 air sampling stations, North Hall and an Area 1 control station at the Environmental Health and Safety Center.

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2. AIR MONITORING (TABLES 2.1, 2.2, 2.3 and 2.4)

Air monitoring is performed continually for one week during each of four (4) quarters during the year. The data in Table 2.2 are for gross beta activity levels measured during the year. The highest gross beta activity observed was 20.4 fCi/cubic meter at the Polk Hall station during the week of 10/07/2021 to 10/13/2021. The annual campus average value was 12.2 fCi/cubic meter.

Table 2.3 lists LLD values for several gamma emitters which would be indicative of fission product activity. No gamma activity due to any of these radionuclides was detected.

Table 2.4 lists regulatory limits, alert levels, and average background levels for airborne radioactivity.

TABLE 2.1 LOCATION OF AIR MONITORING STATIONS SITE DIRECTION1 DISTANCE2 ELEVATION3 (meters) (meters)

LAMPE

• SOUTHEAST 90 -8 WITHERS NORTHEAST 82 -6 EHS CENTER WEST 1230 -3 NORTH HALL ** NORTHEAST 402 -4 POLK HALL WEST 100 -7 1

DIRECTION - DIRECTION FROM REACTOR STACK 2

DISTANCE - DISTANCE FROM REACTOR STACK 3

ELEVATION - ELEVATION RELATIVE TO THE TOP OF THE REACTOR STACK

• • ONLY DOSIMETER MONITORING

• LAMPE was formerly named DANIELS

3 TABLE 2.2 Airborne Gross Beta Activity (fCi/cubic meter +/- 2)

PERIOD Polk Lampe Withers EH&S 2021 03/11-03/18 14.7 +/- 1.4 11.3 +/- 1.3 11.2 +/- 1.3 14.1 +/- 1.4 06/22-06/29 8.3 +/- 1.2 11.3 +/- 1.3 8.8 +/- 1.2 9.5 +/- 1.3 09/13-09/19 11.1 +/- 1.3 11.0 +/- 1.3 6.3 +/- 1.2 16.1 +/- 1.5 10/07-10/13 20.4 +/- 1.4 15.6 +/- 1.2 14.5 +/- 1.2 11.1 +/- 1.1 PERIOD Co-57 Co-60 Nb-95 Zr-95 Ru-103 Ru-106 Cs-137 Ce-141 Ce-144 2021 03/11- 03/18 0.18 0.57 0.40 0.68 0.29 3.27 0.40 0.30 1.34 06/22 - 06/29 0.17 0.52 0.45 0.81 0.32 3.33 0.39 0.33 1.28 09/13 - 09/19 0.17 0.52 0.49 0.72 0.31 3.35 0.41 0.32 1.29 10/07 - 10/13 0.17 0.52 0.36 0.74 0.30 3.35 0.38 0.31 1.33 TABLE 2.3 Airborne Gamma Activity LLD Values (fCi/cubic meter)

4 TABLE 2.4 REGULATORY LIMITS, ALERT LEVELS, AND BACKGROUND LEVELS FOR AIRBORNE RADIOACTIVITY (fCi M 3).

REGULATORY INVESTIGATION *AVERAGE N.C.

NUCLIDE LIMIT LEVEL BACKGROUND LEVEL GROSS BETA 1000 500 20 Cs-137 2 X 105 100 2 Ce-134 2 X 105 100 0 Nb-95 2 X 106 100 0 Zr-95 400 100 0

• This data represents an average value measured in North Carolina at various locations.

Excerpted from 2009 Environmental Surveillance Report produced by the NC Department of Health and Human Services Radiation Protection Section.

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3. MILK (TABLE 3.1)

Milk samples are collected every other year from the Campus Creamery and the Lake Wheeler Road Dairy as processed milk and raw milk and analyzed for I-131.

TABLE 3.1 I-131 IN COWS MILK (pCi Liter -1 +/- 2 ) LLD ~ 2 pCi Liter -1 pCi Liter 1 DATE Campus Creamery Lake Wheeler 09-24-21 Not Detected Not Detected 6

4. SURFACE WATER (TABLES 4.1 AND 4.2)

Table 4.1 gives the gross alpha and beta activities for water from Rocky Branch at points where it enters (ON), behind Carmichael Gymnasium (GYM) and exits (OFF) the campus. The LLD value for gross alpha and beta activities is ~ 0.4 pCi Liter-1. For gross alpha activity the Investigation Level is 5 pCi Liter-1 and the Regulatory Limit is 15 pCi Liter-1. For gross beta activity the Investigation Level is 12.5 pCi Liter-1 and the Regulatory Limit is 50 pCi Liter-1. Gamma analysis of all samples was also performed. All the results are consistent with the presence of naturally-occurring radionuclides and none of the gamma emitters listed in Table 4.2 were detected.

TABLE 4.1 GROSS ALPHA AND BETA ACTIVITY IN SURFACE WATER (pCi Liter 1 +/- 2)

LLD ~ 0.4 pCi Liter-1 LLD ~ 0.4 pCi Liter 1 pCi Liter 1 GROSS GROSS DATE LOCATION ALPHA BETA FIRST QUARTER 2021 ON 0.2 +/- 0.2 3.5 +/- 0.6 OFF 0.1 +/- 0.1 2.8 +/- 0.6 GYM 0.2 +/- 0.2 3.6 +/- 0.6 SECOND QUARTER 2021 ON 0.2 +/- 0.2 3.5 +/- 0.7 OFF 0.2 +/- 0.2 2.5 +/- 0.6 GYM 0.2 +/- 0.2 3.5 +/- 0.7 THIRD QUARTER 2021 ON 0.1 +/- 0.2 3.9 + 0.7 OFF 0.1 +/- 0.2 3.7 + 0.7 GYM 0.2 +/- 0.2 4.3 + 0.7 FOURTH QUARTER 2021 ON 0.2 +/- 0.2 2.7 + 0.6 OFF 0.1 +/- 0.2 3.3 + 0.6 GYM 0.2 +/- 0.2 2.9 + 0.6 7

TABLE 4.2 LLD VALUES FOR GAMMA EMITTERS IN SURFACE WATER NUCLIDE LLD (pCi Liter-1)

Co-60 0.4 Zn-65 0.7 Cs-137 0.3 Cs-134 0.4 Sr-85 0.4 Ru-103 0.3 Ru-106 3.0 Nb-95 0.4 Zr-95 0.5 8

5. VEGETATION (TABLE 5.1 & 5.2)

Tables 5.1 gives gross beta activities for grass samples collected on the NCSU Campus. Table 5.2 lists LLD values for several gamma emitters. No gamma emitters were detected.

The vegetation sampling is performed every other year.

TABLE 5.1 GROSS BETA ACTIVITY IN CAMPUS VEGETATION

• LLD 0.5 pCi g-1 SAMPLE DATE SAMPLE LOCATION (pCi g-1 +/- 2) 09-16-21 NORTH CAMPUS 3.5 +/- 0.4 09-16-21 SOUTH CAMPUS 5.0 +/- 0.4 09-16-21 EAST CAMPUS 7.3 +/- 0.5 09-16-21 WEST CAMPUS 9.2 +/- 0.5 TABLE 5.2 LLD VALUES FOR GAMMA EMITTERS IN VEGETATION NUCLIDE LLD (pCi gram-1)

Co-60 0.01 Zn-65 0.02 Cs-137 0.01 Cs-134 0.01 Sr-85 0.01 Ru-103 0.01 Nb-95 0.01 Zr-95 0.02 9

6. OPTICALLY STIMULATED DOSIMETERS (TABLE 6.1)

Dosimeter analysis is contracted to Landauer, Inc. for determination of ambient radiation exposures.

Exposures are integrated over a three-month period at each of the air monitor stations listed in Table 2.1 and at the PULSTAR Reactor facility. An Area 1 control dosimeter is located in the Environmental Health & Safety Center. Table 6.1 gives the dose equivalent data for these seven (7) locations.

The dose equivalents are reported as millirem per quarter year. Readings which fall below the dosimeters minimum measurable quantities (i.e., 1 millirem for gamma radiations and 10 millirem for beta radiation) are reported by the contract vendor with the designation M. The observed readings are typically within the expected range for natural background radiation levels.

TABLE 6.1 ENVIRONMENTAL DOSIMETER DOSES - Millirem per Quarter Period Landauer Control Polk Withers Lampe EHS North PULSTAR Control Area 1 2021 01/01- 43 M M,M M,M M,M M M 9 03/31 04/01- 46 M M,M M,M M,M M M 9 06/30 07/01- 45 2 M,M M,M M,M M 1 14 09/30 10/01- 51 M M,M M,M M,M M M 20 12/31 Note: Landauer Control dose is measured by the vendors Control Dosimeter which is included with each shipment to monitor radiation exposure received during transit. It is maintained in a radiation free area during the calendar quarter period.

Control Area 1 dose is measured by a dosimeter maintained in an office location away from radiation sources.

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7. QUALITY CONTROL INTERCOMPARISON PROGRAM The Environmental Radiation Surveillance Laboratory (ERSL) in the Radiation Safety Division has analyzed samples provided by the U.S. DOE Mixed-Analyte Performance Evaluation Program (MAPEP Test Session 45) Radiological and Environmental Sciences Laboratory (RESL) during this reporting period. The objective of this program is to provide laboratories performing environmental radiation measurements with unknowns to test their analytical techniques.

The MAPEP value listed in the Tables 7.1 (a&b) to which the ERSL results are compared is the mean of replicate determinations for each nuclide. The MAPEP uncertainty is the standard error of the mean.

For each reported radiological analyte, the laboratory result and the reference value may be used to calculate a relative bias:

(100)(Laboratory Re sult RESL Re ferenceValue)

%Bias =

RESL Re ferenceValue The relative bias will place the laboratory result in one of three categories:

Acceptable Bias 20%

Acceptable with Warning... 20% < Bias 30%

Not Acceptable. Bias > 30%

11 TABLE 7.1a

MULTINUCLIDE WATER SAMPLE - INTERCOMPARISON STUDY 01 August 2021 The sample consists of a spiked aliquot of acidified water (~5 % HNO3). The reported values and the known values are given in Bq/Liter.

• NCSU - ENVIRONMENTAL LABORATORY RESULTS Radionuclide *Reported *Reported MAPEP Acceptance Value Error Value Range Co60 14.11 0.48 14.0 9.8 - 18.2 Cs137 0.83 1.0 -------- False + Test Cs134 10.24 0.62 10.4 7.3 - 13.5 Co57 13.66 0.39 13.9 9.7 - 18.1 Mn54 9.71 0.67 9.0 6.3 - 11.7 Zn65 0.50 1.0 -------- False + Test Gross Alpha 0.04 0.11 0.232 0.070 - 0.394 Gross Beta 2.82 0.10 2.807 1.404 - 4.211 Note: The entry ------indicates no analyte was present for purposes of conducting a False Positive (+) Test.

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TABLE 7.1b MULTINUCLIDE AIR FILTER - INTERCOMPARISON STUDY 01 August 2021 The sample consists of one 50 mm diameter glass fiber filter which has been spiked with a solution and dried. The reported values and the known values are given in Bq/filter.

• NCSU - ENVIRONMENTAL LABORATORY RESULTS Radionuclide *Reported *Reported MAPEP Acceptance Value Error Value Range Co60 2.03 0.04 0.228 1.60 - 2.96 Cs137 1.11 0.04 1.28 0.90 - 1.66 Cs134 1.34 0.08 1.32 0.92 - 1.72 Co57 0.83 0.02 0.83 0.58 -1.08 Mn54 1.42 0.02 1.46 1.02 - 1.90 Zn65 0.07 0.10 ------ False + Test Gross Alpha 0.91 0.03 0.960 0.288 - 1.632 Gross Beta 0.46 0.01 0.553 0.277 - 0.830 Note: The entry ------indicates no analyte was present for purposes of conducting a False Positive (+) Test.

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8. CONCLUSIONS The data obtained during this period do not show any fission product activities. The observed environmental radioactivity is due primarily to radon progeny, primordial radionuclides (e.g. K-40) and those radionuclides which originate in the upper atmosphere as the result of cosmic ray interactions. These facts justify the conclusion that the PULSTAR Reactor facility continues to operate safely and does not release fission product materials into the environment.

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