HBL-20-009, Annual Radiological Environmental Monitoring Report for 2019

Annual Radiological Environmental Monitoring Report for 2019

ML20121A264
Person / Time
Site:	Humboldt Bay
Issue date:	04/30/2020
From:	Sharp L Pacific Gas & Electric Co
To:	Document Control Desk, Office of Nuclear Material Safety and Safeguards, Office of Nuclear Reactor Regulation
References
HBL-20-009
Download: ML20121A264 (45)

Text

Pacific Gas and Loren D. Sharp Diablo Canyon Power Plant Senior Director P.O. Box56 Electric Company"' Nuclear Decommissioning Avila Beach, CA 93424 Phone: 805.545.6003 Email: Loren.Sharp@pge.com April 30, 2020 PG&E Letter HBL-20-009 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Docket No. 50-133, DPR-7 Humboldt Bay Power Plant Unit 3 Annual Radiological Environmental Monitoring Report for 2019

Dear Commissioners and Staff:

Enclosed is the Humboldt Bay Power Plant Unit 3, "Annual Radiological Environmental Monitoring Report," for 2019. This report provides the information required by Section 4.1 of the SAFSTOR/Decommissioning Offsite Dose Calculation Manual (ODCM).

The report has three sections. Section A provides a summary description of the SAFSTOR Radiological Environmental Monitoring Program (REMP), including maps of sampling locations. Section A also provides the results of licensee laboratory participation in the lnterlaboratory Comparison Program.

Section B provides summaries, interpretations, and analyses of trends of the results of the REMP for the reporting period. The material provided is consistent with the objectives outlined in the ODCM, and in 10 CFR 50, Appendix I, Sections IV.B.2, IV.B.3, and IV.C. Section B also includes a comparison with the baseline environmental conditions at the beginning of SAFSTOR.

Section C provides monitoring results for the reporting period. Radiological environmental samples and environmental radiation measurements were taken at the locations identified in ODCM Table 2-7 as quality-related locations. The summarized results are formatted for applicable reporting requirements of Generic Letter 79-65, "Radiological Environmental Monitoring Program Requirements -

Enclosing Branch Technical Position," Revision 1, dated November 27, 1979.

There are no new or revised regulatory commitments (as defined in NEI 99-04) in this submittal.

Document Control Desk PG&E Letter HBL-20-009 April 30, 2020 Page2 If you have any questions regarding information in the enclosed report, please contact Mr. Philippe Soenen at (805) 459-3701.

Loren D. Sharp Senior Director, Nuclear Decommissioning Enclosure cc: HBPP Humboldt Distribution cc/enc: John 8. Hickman, NRC Project Manager Scott A.Morris, NRC Region IV Administrator

Enclosure PG&E Letter HBL-20-009 HUMBOLDT BAY POWER PLANT UNIT 3 ANNUAL RADIOLOGICAL ENVIRONMENTAL MONITORING REPORT JANUARY 1 THROUGH DECEMBER 31, 2019

TABLE OF CONTENTS A. RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ............................ 1

1. Program Description ............................................................................................ 1

2. Monitoring Requirements ..................................................................................... 2

a. Offsite Environmental Monitoring ................................................................... 2

b. Onsite Environmental Monitoring ................................................................... 3

c. Other Monitoring ............................................................................................. 4

3. Interlaboratory Comparison Program ................................................................... 4

4. NEI Groundwater Protection Initiative .................................................................. 5 B. TRENDS, BASELINE COMPARISONS AND INTERPRETATIONS ......................... 5

1. General Comments.............................................................................................. 5

2. Direct Radiation Pathway .................................................................................... 6

3. Airborne Pathway ................................................................................................ 7

4. Waterborne Pathway ........................................................................................... 7

a. Surface Water ................................................................................................ 7

b. Groundwater................................................................................................... 7

5. Ingestion Pathway ............................................................................................... 7

6. Terrestrial Pathway .............................................................................................. 8 C. MONITORING RESULTS ......................................................................................... 8

1. Annual Summary ................................................................................................. 8

2. Direct Radiation Pathway .................................................................................... 9

3. Airborne Pathway .............................................................................................. 10

4. Waterborne Pathway ......................................................................................... 12

a. Surface Water .............................................................................................. 12

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TABLE OF CONTENTS (Continued)

b. Groundwater.............................................................................. .12

5. Ingestion Pathway ............................................................................................. 12

6. Terrestrial Pathway ........................................................................................... .12

7. NEI Groundwater Protection Initiative Voluntary Reporting Results........12

8. Errata For Previous Years Reports ...................................13

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LIST OF TABLES Table Page A-1 HBPP RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ............ 14 A-2 DISTANCES AND DIRECTIONS TO HBPP OFFSITE SAMPLE LOCATIONS ... 14 A-3 GEL PARTICIPATION - INTERLABORATORY CROSS-CHECK PROGRAM.

DATA..15 A-4 HBPP PARTICIPATION - ECKERT & ZIEGLER INTERLABORATORY .

CROSS-CHECK PROGRAM DATA ..................................................................... 19 C-1 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANNUAL REPORT

SUMMARY

........................................................................................... 25 C-2 ONSITE ENVIRONMENTAL TLD STATIONS ...................................................... 27 C-3 OFFSITE (Control) ENVIRONMENTAL TLD STATIONS ..................................... 28 C-4 ODCM REQUIRED AIR SAMPLES ...................................................................... 29 LIST OF FIGURES Figure Page A-1 HBPP ONSITE AIR SAMPLE LOCATIONS ......................................................... 37 A-2 HBPP OFFSITE AIR SAMPLE LOCATION .......................................................... 38 A-3 HBPP ONSITE TLD LOCATIONS ........................................................................ 39 A-4 HBPP OFFSITE TLD LOCATIONS ...................................................................... 40 B-1 OFFSITE ENVIRONMENTAL RADIATION LEVEL TRENDS .............................. 43 B-2 ONSITE ENVIRONMENTAL RADIATION LEVEL TRENDS ................................ 44

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PACIFIC GAS AND ELECTRIC COMPANY ANNUAL RADIOLOGICAL ENVIRONMENTAL MONITORING REPORT FOR HUMBOLDT BAY POWER PLANT UNIT 3, COVERING THE PERIOD JANUARY 1 THROUGH DECEMBER 31, 2019 This annual report is required by Section 4.1 of the SAFSTOR/Decommissioning Offsite Dose Calculation Manual (ODCM). This report provides information about the Radiological Environmental Monitoring Program (REMP) for the period of January 1 through December 31, 2019, in a manner consistent with the objectives outlined in the ODCM, and in 10 CFR Part 50, Appendix I, Sections IV.B.2, IV.B.3, and IV.C.

The report has three sections. Section A provides a summary description of the REMP, including maps of sampling locations. Section A also provides the results of licensee laboratory participation in the Interlaboratory Comparison Program.

Section B provides summaries, interpretations, and analyses of trends of the results of the REMP for the reporting period. The material provided is consistent with the objectives outlined in the ODCM, and in 10 Part CFR 50, Appendix I, Sections IV.B.2, IV.B.3, and IV.C. Section B also includes a comparison with the baseline environmental conditions at the beginning of SAFSTOR.

Section C provides the results of analyses of radiological environmental samples and of environmental radiation measurements taken during the period pursuant to the quality related locations specified in the table and figures in the ODCM, presented as both summarized and tabulated results of these analyses and measurements. The summarized results are formatted for applicable reporting requirements of the NRC Radiological Assessment Branchs Branch Technical Position.

A. RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM

1. Program Description The NRC Radiological Assessment Branch issued a Branch Technical Position (BTP) on environmental monitoring in March 1978. Revision 1 of the BTP was issued as Generic Letter 79-65, Radiological Environmental Monitoring Program Requirements - Enclosing Branch Technical Position, Revision 1, dated November 27, 1979, and sets forth an example of an acceptable minimum radiological monitoring program. The specified environmental monitoring program provides measurements of radiation and of radioactive materials in those exposure pathways and for those radionuclides that lead to the highest potential radiation exposures of individuals resulting from plant effluents.

As discussed below, many of the exposure pathway sample requirements specified in the BTP are not required for the Humboldt Bay Power Plant (HBPP)

REMP because of the baseline conditions established in the SAFSTOR Decommissioning Plan (now identified as the Post Shutdown Decommissioning Activities Report (PSDAR) and Defueled Safety Analysis Report (DSAR)) and the Environmental Report.

In addition, the nuclides specified for analysis by the BTP have been revised to reflect the available source term at a nuclear power plant that has been shut down since July 2, 1976.

The REMP consists of the collection and analysis of both onsite and offsite environmental samples. HBPP personnel perform sample collection and sample analysis of airborne radioactivity. General Engineering Laboratories (GEL) personnel no longer perform effluent sample analyses as ground water radioactivity monitoring was discontinued in 2017. Mirion Technologies personnel perform analysis of thermoluminescent dosimeters (TLDs) used for monitoring direct radiation. A summary of the REMP is provided as Table A-1, HBPP RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM.

Sample collection for the REMP is performed at the sampling stations defined by Table A-2, DISTANCES AND DIRECTIONS TO HBPP OFFSITE SAMPLE LOCATIONS, Figure A-1, HBPP ONSITE AIR SAMPLE LOCATIONS; Figure A-2, HBPP OFFSITE AIR SAMPLE LOCATION; Figure A-3, HBPP ONSITE TLD LOCATIONS, and Figure A-4 HBPP OFFSITE TLD LOCATIONS.

2. Monitoring Requirements

a. Offsite Environmental Monitoring

1. Airborne The ODCM requires one (1) offsite environmental air sampling station.

The air sampler is run continuously, and samples are analyzed weekly for Gross Beta and Gross Alpha activity. Station 3 satisfies this requirement as shown on Figure A-2. The composited samples are analyzed quarterly for Gamma Isotopic.

2. Direct Radiation The ODCM requires four (4) offsite environmental monitoring stations and one (1) offsite control station equipped with TLDs to monitor gamma exposure. The TLDs are required to be exchanged quarterly. Offsite environmental stations selected to satisfy this requirement are Stations 1, 2, 14, 25, while T17 is the offsite control station as shown on Figure A-4.

These stations are considered to represent the offsite locations for the direct radiation pathway.

3. Ingestion The requirement to perform milk sampling was removed from the ODCM in Revision 24 based upon no detection of Sr-90 or plant-related gamma emitters in milk since decommissioning began.

b. Onsite Environmental Monitoring

1. Airborne The ODCM requires two (2) onsite air sampling stations. The stations selected to satisfy this requirement are Stations AM2 and AM4 as shown on Figure A-1. The air samplers are run continuously, and samples are analyzed weekly for Gross Beta and Gross Alpha activity. The composited samples are analyzed quarterly for Gamma Isotopic, by station. The number of onsite air sampling stations was reduced from four (4) to two (2) during 2019. Also, continuously is currently defined to be during onsite work activities. These adjustments were made to the environmental monitoring program during 2019 to accommodate the progress of decommissioningthe elimination of any effluent pathway other than active work evolutions and difficulty in maintaining power supplies during non-active work hours to remote areas of the site. The three remaining air sampling locations generally represent two major compass sectors (N, S) and areas that are potentially approachable by a member of the public.

2. Direct Radiation The ODCM requires a minimum of 8 onsite environmental monitoring stations at or within the site boundary fence line, equipped with TLDs to monitor gamma exposure. TLDs are required to be exchanged quarterly.

A total of 16 TLD stations are currently used to satisfy this requirement.

Stations T1 through T16 are shown on Figure A-3.

The exposures from 16 stations are determined quarterly, which normally results in 64 analyses for a full year. Each TLD station has three TLDs, each containing a number of phosphors (normally three). The phosphor exposures for each TLD are averaged and then the three TLDs per station are averaged to provide the quarterly exposure for the station.

The minimum number of TLDs was modified in the ODCM from 16 to 8 stations to allow monitoring locations to be reduced as source term is removed from the site during the final phase of decommissioning.

3. Waterborne Surface Water Effective December 31, 2013, discharge of processed radioactive liquid effluents to Humboldt Bay was terminated. Any remaining or incidental radioactive liquids in concentrations exceeding 10 times 10 CFR 20, Appendix B, Table 2 Column 2 are manifested for disposal at a regulated disposal facility. Sampling of surface water is not required by the current revision of the ODCM.

Groundwater Revision 23 of the ODCM transferred ground water monitoring program requirements from the ODCM to HBPPs ground water monitoring program procedures. This was done to allow operational flexibility needed to adjust to changes to site access and hydrogeology as soils and building substructures are removed. After May 2017, formal closure of the ground water monitoring program was initiated. There were no well locations sampled in 2019.

c. Other Monitoring Offsite airborne, ingestion, and terrestrial pathway monitoring is not required by the ODCM. The Environmental Report, submitted to the NRC as Attachment 6 to SAFSTOR License Amendment Request 84-01, dated July 31, 1984, established baseline conditions for these pathways. In accordance with the NRC-approved SAFSTOR Decommissioning Plan, (now identified as the PSDAR and DSAR), these baseline conditions will only need to be reestablished prior to final decommissioning if a significant release occurs during SAFSTOR. The Environmental Report also contains a description of the demography and human activities within the environs surrounding the site.

3. Interlaboratory Comparison Program PG&Es contract laboratory, GEL, has analyzed evaluation samples provided by a commercial supplier to satisfy the requirement to participate in an Interlaboratory Cross-Check Program. Results are provided in Table A-3, GEL PARTICIPATION - INTERLABORATORY CROSS-CHECK PROGRAM DATA.

With the termination of the ground water monitoring program in 2017, GEL no longer provides analyses of REMP samples for HBPP.

GELs Third-Party Cross-Check Program provides environmental matrices representative of past HBPP analyses and is intended to meet or exceed the interlaboratory comparison program requirements of NRC Regulatory Guide 4.15. GEL analyzed 92 Eckert & Ziegler individual environmental sample analyses. All results met GELs acceptance criteria (100 percent within acceptance).

HBPP count room personnel also participated in the Eckert & Ziegler Interlaboratory Cross-Check Program. This participation includes sufficient determinations (sample medium and radionuclide combination) to ensure independent checks on the precision and accuracy of the measurements of radioactive materials in REMP samples. Table A-4, HBPP PARTICIPATION -

ECKERT & ZIEGLER INTERLABORATORY CROSS-CHECK PROGRAM DATA, represent analyses performed by HBPP personnel (Table A-4). The agreement criteria are consistent with the guidance for Confirmatory Measurements as described in NRC Inspection Procedure 83502.03, Radiological Environment Monitoring Program and Radioactive Material Control Program.

HBPP analyzed three sets of Eckert & Ziegler Analytics samples for gamma in soil, (first quarter), gamma air filter and alpha/beta air filter (second quarter), and gamma in water and tritium in water (third quarter). These analyses are representative of those performed by HBPP count room personnel during 2019.

All results met the acceptance criteria.

Corrective action SAPN 1448716, created on December 8, 2018, was the procurement SAPN for the 2019 Cross-Check Program. Due to a procurement issue, the 2019 first quarter cross check was not received until mid-May. HBPP analysis results were found to be acceptable in comparison with Eckert & Ziegler reported results except for the Ce-141 value, which was outside the agreement ratio range, but was reported by HBPP as conservatively high. Ce-141 has a 32.5-day half-life and is not included as part of the known suite of radionuclides present at HBPP. All actions were documented in corrective action SAPN 1452043.

4. NEI Groundwater Protection Initiative Based on the state of decommissioning at HBPP, there remains little potential for ground water to become contaminated during the final stages of decommissioning. Formal closure of the ground water monitoring wells was initiated in 2017 and continued into 2019. Ground water monitoring wells were closed in accordance with local water authority guidance and permits under Work Package 99-28, Well Abandonment. Sampling of ground water monitoring wells was discontinued after the second quarter of 2017.

B. TRENDS, BASELINE COMPARISONS AND INTERPRETATIONS Section B provides interpretations of results and analyses of trends of the results. The material provided is consistent with the objectives outlined in the ODCM, and in 10 CFR Part 50, Appendix I, Sections IV.B.2, IV.B.3, and IV.C.

Section B also includes a comparison with the baseline environmental conditions at the beginning of SAFSTOR.

1. General Comments The Environmental Report, submitted to the NRC as Attachment 6 to SAFSTOR License Amendment Request 84-01, established baseline conditions for soil, biota, and sediments. The results to date indicate no change from the baseline environmental conditions established in the Environmental Report.

The results, interpretations, and analysis of trends of the results indicate that SAFSTOR activities have had no measurable radiological effect on the environment. Facility surveys for radiation and radioactive surface contamination are performed on both a scheduled basis and on an as-required basis. These surveys indicate that the radioactivity control barriers established for SAFSTOR and decommissioning continue to be effective.

As discussed below, the ODCM calculation model conservatively assumes that exposure pathways begin at the unrestricted area boundary, also known as the owner-controlled area (OCA) boundary. Since there have been no changes in the location of the unrestricted area boundary, no survey for changes to the use of unrestricted areas was necessary.

2. Direct Radiation Pathway A plot of the radiation level trends for the five (offsite) locations is shown in Figure B-1, OFFSITE ENVIRONMENTAL RADIATION LEVEL TRENDS. A plot of the radiation level trends for onsite stations is shown in Figure B-2, ONSITE ENVIRONMENTAL RADIATION LEVEL TRENDS. The plots show that the offsite annual doses continue to be within the ranges that have been observed over the last ten years.

HBPP changed TLD processing services beginning in January 2014. Data from previous years was based on a Panasonic TLD system. Data in 2014 to the present is based on Mirion Genesis type TLD system. The apparent rise in Figures B-1 and B-2 after 2014 may be a result of the change in monitoring devices in tandem with the increase in decommissioning activities.

Figure B-2 includes the average dose for two groups of onsite stations, selected by their potential to be affected by radioactive waste handling activities. Figure B-2 also shows that dose measurement variations can be attributed to in-plant sources and low-level waste packaging and shipping activities. However, allowing for the background change in the general environs, all measurements were comparable to the ranges observed at these locations since entering SAFSTOR, with the onsite station dose levels approximately within the range of dose levels shown by the offsite stations.

The ODCM calculation model for the direct radiation exposure pathway in past years assumed an occupancy factor for the portion of the unrestricted area boundary that was closest to the radioactive waste handling area of the plant.

During 2019, maximum yearly dose was seen on TLD T9, corrected to the 67-hour occupancy, and subtracting the average of the five (5) offsite TLDs, the dose to the maximum exposed individual from this source was approximately 0.1 millirem (mrem) above background.

The Humboldt Bay independent spent fuel storage installation (ISFSI) is licensed under 10 CFR Part 72, but is contained within the licensed boundary of the HBPP site, so no other dose contributions to the public are considered. The HBPP site had no measurable liquid or gaseous radioactive effluents that would challenge the limitations of 40 CFR 190. The direct dose is the only contributor to public dose and is within the 25 mrem limit to the whole body.

3. Airborne Pathway Dose assessment based on offsite airborne pathway monitoring is not required by the ODCM. The Environmental Report, submitted to the NRC as Attachment 6 to SAFSTOR License Amendment Request 84-01, established baseline conditions for the airborne pathway. In accordance with the NRC-approved SAFSTOR Decommissioning Plan, (now identified as the PSDAR and DSAR),

these baseline conditions will only need to be reestablished prior to final decommissioning if a significant release occurs during SAFSTOR. The ODCM calculation model for the airborne pathway assumes that the airborne exposure pathway (inhalation exposure) is at the unrestricted area boundary, which is the location of the highest potential exposure.

4. Waterborne Pathway

a. Surface Water Liquid radioactive wastes are shipped for disposal to a regulated disposal facility. Discharges of liquid radioactive effluent to Humboldt Bay were eliminated after December 2013.

b. Groundwater Groundwater sampling of the waterborne pathway ceased in the second quarter of 2017. There were no spills challenging the groundwater in 2019.

The ODCM does not provide a model for the groundwater waterborne pathway, because the groundwater is saline and is not used now nor likely to be used in the future for either direct consumption or for agricultural purposes.

5. Ingestion Pathway Ingestion pathway monitoring is not required by the ODCM. The Environmental Report, submitted to the NRC as Attachment 6 to SAFSTOR License Amendment Request 84-01, established baseline conditions for the ingestion pathway. In accordance with the NRC-approved SAFSTOR Decommissioning Plan, (now identified as the PSDAR and DSAR), these baseline conditions will only need to be reestablished prior to final decommissioning if a significant release occurs during SAFSTOR.

The ODCM calculation model for the airborne pathway assumes that the ingestion pathways (milk, meat and vegetable consumption) begin at the unrestricted area boundary, which is the location of the highest potential exposure, whether any dairy, farm, etc. is actually present.

6. Terrestrial Pathway Terrestrial pathway monitoring is not required by the ODCM. The Environmental Report, submitted to the NRC as Attachment 6 to SAFSTOR License Amendment Request 84-01, established baseline conditions for the terrestrial pathway. In accordance with the NRC-approved SAFSTOR Decommissioning Plan, (now identified as the PSDAR and DSAR), these baseline conditions will only need to be reestablished prior to final decommissioning if a significant release occurs during SAFSTOR.

The ODCM calculation model for the terrestrial pathway conservatively assumes that the terrestrial exposure (direct radiation from airborne radioactivity deposition) is at the unrestricted area boundary, which is the location of the highest potential exposure.

C. MONITORING RESULTS

1. Annual Summary Results of the REMP sampling and analysis are summarized in Table C-1 in the format of the BTP Table 3.

All the minimum detectable activities (MDAs) for analyses required by the REMP were less than or equal to the lower limit of detection (LLD) criteria for radioactivity in environmental samples specified in Table C-1 of this report.

Because alpha and beta radioactivity analyses of the saline ground water are less effective than tritium and gamma radioactivity analyses, the ODCM does not currently require alpha and beta radioactivity analyses in water to be part of the REMP. However, HBPP maintains gamma and tritium in water analysis capability as a prerequisite to evaluate ground water/storm water radioactivity for GWTS (ground water treatment system), independent of the REMP program.

2. Direct Radiation Pathway Monitoring of the direct radiation pathway is performed at 16 onsite locations near the OCA fence line, and at 4 offsite environmental monitoring stations and one offsite (control) location (Location number T17) near the facility. Monitoring is performed with TLDs with multiple crystal elements. Three TLDs are installed at each station, and the TLD sets are exchanged quarterly. The reported result and its standard error are calculated from the measurements of multiple elements in the TLD triplet. Results of the onsite and offsite monitoring are provided in Tables C-2 and C-3, respectively.

Offsite TLD Station T1 was moved approximately 20 feet on February 26, 2019, to allow cutting of vegetation and removal of fencing. The relocation was documented in corrective action SAPN 1450240.

Onsite TLD Stations T9 and T10 were relocated from temporary fence posts to permanent fencing on May 3, 2019, and new GPS coordinates were obtained.

The relocation was documented in corrective action SAPN 1450240.

On May 6, 2019, Onsite TLD Station T8 was moved closer to TLD T7 on the Coastal Trail Fence due to environmental remediation within the immediate area. On May 9, 2019, T8 was removed from the Coastal Trail Fence and transferred to Building 13. The excavated area appeared to be expanding so T8 was removed from the fence line to prevent the TLD from being lost. TLD T7 was removed from the fence line and transferred to Building 13 on May 20, 2019, for the same reasons. TLD T6, also located on the Coastal Trail Fence, was removed on June 13, 2019, due to environmental remediation. T6 was also transferred to Building 13. Onsite TLD Station T5 was pulled from the Coastal Trail Fence on June 27, 2019, again due to environmental remediation along the Coastal Trail Fence and transferred to Building 13. All TLD relocations were documented in corrective action SAPN 1450240. Onsite TLD Stations T5, T6, T7, and T8 were installed on new permanent fencing at the station perimeter on July 25, 2019.

Onsite TLD Station T11 was relocated from the East Fence (AM1) air sampler doghouse to permanent fencing within the immediate vicinity of the air sampler on August 7, 2019. The East Fence air sampler is scheduled to be eliminated due to electrical power issues. The transfer was documented in corrective action SAPN 1450240.

The 2019 first quarter TLD report contained two anomalies. T8A registered 3 elements with exposures of 14 mR, 12 mR, and 135 mR. T8B displayed exposures of 12 mR, 11 mR, and 12 mR. T8C showed measurements of 12 mR, 13 mR, and 13 mR. The 135 mR measurement was discarded by Mirion as not valid. The second anomaly was T9A with readings of 14 mR, 14 mR ,and 13 mR while T9B displayed readings of 35 mR, 13 mR, and 13 mR.

T9C displayed readings of 14 mR, 14 mR, and 14 mR. The 35 mR measurement also appeared to be artificially high above the average and the decision was made to delete the measurement from the calculated average. All actions were documented in corrective action SAPN 1453104.

3. Airborne Pathway Four onsite samples and one offsite sample were collected and analyzed weekly for Gross Beta and Gross Alpha activity until August 28, 2019, when AM1 (East Fence) was removed from service due electrical power issues. The ODCM was revised to require only three (3) onsite air samplers. This was documented in corrective action SAPN 1450240 The required quarterly composited samples were analyzed for Gamma Isotopic by station. All air sample results for alpha and beta activity and quarterly composite results for Co-60 and Cs-137 are provided in Table C-4. The weekly sample results for alpha and beta particulate met the effluent acceptance criteria in the ODCM. All LLDs were met for Gross Beta (required LLD 1.0E-02 pCi/m3).

Interruptions of continuous REMP air sampler operations occurred on the following dates due to ongoing decommissioning activities and were entered into the corrective action program as documented below:

Date SAPN Description 01/30/2019 1450240 The offsite REMP air sampler at Humboldt Hill was found to be not operating due to a tripped GFCI.

The air sampler had run for approximately 95 hours0.0011 days <br />0.0264 hours <br />1.570767e-4 weeks <br />3.61475e-5 months <br />.

The totalizer reading was used to calculate sample volume and the resultant sample activity.

05/01/2019 1450240 The REMP air sampler adjacent to GWTS was relocated to the road adjacent to the ISFSI. The air sampler was turned off for approximately 20 minutes during relocation activities. The change in location was due to discontinuing GWTS operations and resultant loss of electrical power for the air sampler.

06/25/2019 1450240 The offsite REMP air sampler at Humboldt Hill was discovered to be not operating after approximately 118 hours0.00137 days <br />0.0328 hours <br />1.951058e-4 weeks <br />4.4899e-5 months <br /> of run time. Electrical power to the sample station may have been shut down to allow grass trimming around the perimeter of the sample station.

08/28/2019 1450240 The East Fence air sampler (AM1) was powered off and retired from service due to electrical power issues. As a result, the ODCM Revision 30 was revised to reduce the number of required onsite air sampling stations from 4 to 3.

4. Waterborne Pathway

a. Surface Water Surface water sampling of the waterborne pathway is no longer performed due to the termination of liquid effluent releases in December 2013.

b. Groundwater Groundwater sampling of the waterborne pathway ceased in the second quarter of 2017.

5. Ingestion Pathway Ingestion pathway monitoring is not required by the ODCM.

6. Terrestrial Pathway Terrestrial pathway monitoring is not required by the ODCM.

7. NEI Groundwater Protection Initiative Voluntary Reporting Results The NEI Groundwater Protection Initiative contains the following requirements:

OBJECTIVE 2.2 VOLUNTARY COMMUNICATION Make informal notification as soon as practicable to appropriate State/Local officials, with follow up notification to the NRC, as appropriate, regarding significant onsite leaks/spills into groundwater and onsite or offsite water sample results exceeding the criteria in the REMP as described in the ODCM/ODAM.

HBPP Response to 2.2:

There were no reports or notifications required to be generated in 2019 for groundwater results exceeding reporting/notification levels or significant onsite leaks/spills.

OBJECTIVE 2.3 THIRTY-DAY REPORTS Submit a 30-day report to the NRC for any water sample result for onsite groundwater that is or may be used as a source of drinking water that exceeds the criteria in the licensee's existing REMP for 30-day reporting of offsite water sample results. Copies of 30-day reports for both onsite and offsite water samples will also be provided to the appropriate State agency, and:

HBPP Response to 2.3:

There were no reports or notifications required to be generated in 2019 for groundwater results exceeding reporting/notification levels or significant onsite leaks/spills.

OBJECTIVE 2.4 ANNUAL REPORTING Document all on-site ground water sample results and a description of any significant on-site leaks/spills into groundwater for each calendar year in the AREOR for REMP or the ARERR for the RETS as contained in the appropriate reporting procedure, beginning with Calendar year 2006.

HBPP Response to 2.4:

Groundwater sampling of the waterborne pathway ceased in the second quarter of 2017.

There were no significant onsite leaks/spills into groundwater in 2019.

Note: the term "significant" is defined by the NEI Initiative as greater than 100 gallons.

8. Errata for Previous Years Reports None.

TABLE A-1 HBPP RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM Exposure Pathway Number of Samples Sampling and Collection Type of Analysis And/Or Sample And Locations (a) Frequency AIRBORNE Continuous sampler operation Gross alpha and 2 onsite locations with sample collection at least Gross beta once per 7 days radioactivity following filter change. Gamma Isotopic(b) analysis on quarterly composite (by station).

DIRECT RADIATION 8 onsite stations with TLDs TLDs exchanged quarterly Gamma exposure 5 offsite stations with TLDs TLDs exchanged quarterly Gamma exposure WATERBORNE Groundwater No longer required N/A N/A.

(a)

The number of onsite sample / monitoring locations was scaled back in November 2019 (ODCM Revision 31) based on decommissioning status and completion of remediation activities.

(b)

Gamma isotopic analysis means the identification and quantification of gamma emitting radionuclides that may be attributable to the effluents from the facility.

TABLE A-2 DISTANCES AND DIRECTIONS TO HBPP OFFSITE SAMPLE LOCATIONS Radial Direction Offsite Radial Distance Station Measurement By From Plant Number Pathway Station Name Sector Degrees (Miles) 3 Airborne Humboldt Hill SSE 158 0.9 King Salmon 1 Direct Radiation Picnic Area W 270 0.3 2 Direct Radiation City of Fortuna SSE 158 9.4 Water Pollution Control Plant, 180 Dinsmore Drive, Fortuna 14 Direct Radiation South Bay School S 180 0.4 Parking Lot 25 Direct Radiation Irving Drive, SSE 175 1.3 Humboldt Hill T17 Direct Radiation Mitchell Heights NNE 61 5.8 Drive TABLE A-3 GEL PARTICIPATION - INTERLABORATORY CROSS-CHECK PROGRAM DATA Sample/ Radionuclide Sample Quarter Report GEL Reference Ratio Evaluation Analysis Number 2019 Date Value Value (pCi/L) (pCi/L)

Gamma Water I-131 E12367 1st 5/10/19 8.89E+01 8.65E+01 1.03 Acceptable Ce-141 E12367 1st 5/10/19 1.20E+02 1.13E+02 1.06 Acceptable Cr-51 E12367 1st 5/10/19 3.55E+02 2.84E+02 1.25 Acceptable Cs-134 E12367 1st 5/10/19 1.43E+02 1.55E+02 0.92 Acceptable Cs-137 E12367 1st 5/10/19 2.09E+02 1.91E+02 1.10 Acceptable Co-58 E12367 1st 5/10/19 1.43E+02 1.39E+02 1.03 Acceptable Mn-54 E12367 1st 5/10/19 1.55E+02 1.39E+02 1.12 Acceptable Fe-59 E12367 1st 5/10/19 1.76E+02 1.54E+02 1.14 Acceptable Zn-65 E12367 1st 5/10/19 2.44E+02 2.14E+02 1.14 Acceptable Co-60 E12367 1st 5/10/19 3.18E+02 2.90E+02 1.10 Acceptable Sample/ Radionuclide Sample Quarter Report GEL Reference Ratio Evaluation Analysis Number 2019 Date Value Value (pCi/L) (pCi/L)

Milk Ce-141 E12366A 1st 5/10/19 1.23E+02 1.17E+02 1.05 Acceptable Co-58 E12366A 1st 5/10/19 1.51E+02 1.43E+02 1.05 Acceptable Co-60 E12366A 1st 5/10/19 3.12E+02 2.99E+02 1.04 Acceptable Cr-51 E12366A 1st 5/10/19 3.04E+02 2.93E+02 1.04 Acceptable Cs-134 E12366A 1st 5/10/19 1.53E+02 1.60E+02 0.96 Acceptable Cs-137 E12366A 1st 5/10/19 2.04E+02 1.96E+02 1.04 Acceptable Mn-54 E12366A 1st 5/10/19 1.55E+02 1.43E+02 1.08 Acceptable Fe-59 E12366A 1st 5/10/19 1.78E+02 1.59E+02 1.12 Acceptable Zn-65 E12366A 1st 5/10/19 2.42E+02 2.20E+02 1.1 Acceptable Sample/ Radionuclide Sample Quarter Report GEL Reference Ratio Evaluation Analysis Number 2019 Date Value Value (pCi) (pCi)

Cartridge I-131 E12364 1st 05/10/19 7.80E+01 7.54E+01 1.03 Acceptable TABLE A-3 (Continued)

GEL PARTICIPATION - INTERLABORATORY CROSS-CHECK PROGRAM DATA Sample/ Radionuclide Sample Quarter Report GEL Reference Ratio Evaluation Analysis Number 2019 Date Value Value (pCi/L) (pCi/L)

Gamma Water I-131 E12363 2nd 07/29/19 8.92E+01 8.91E+01 1.00 Acceptable Ce-141 E12363 2nd 07/29/19 1.50E+02 1.45E+02 1.03 Acceptable Cr-51 E12363 2nd 07/29/19 3.56E+02 3.68E+02 0.97 Acceptable Cs-134 E12363 2nd 07/29/19 1.37E+02 1.53E+02 0.89 Acceptable Cs-137 E12363 2nd 07/29/19 1.90E+02 1.84E+02 1.03 Acceptable Co-58 E12363 2nd 07/29/19 1.22E+02 1.22E+02 1.00 Acceptable Mn-54 E12363 2nd 07/29/19 2.27E+02 2.07E+02 1.10 Acceptable Fe-59 E12363 2nd 07/29/19 1.73E+02 1.54E+02 1.12 Acceptable Zn-65 E12363 2nd 07/29/19 3.01E+02 2.70E+02 1.11 Acceptable Co-60 E12363 2nd 07/29/19 2.22E+02 2.16E+02 1.03 Acceptable Sample/ Radionuclide Sample Quarter Report GEL Reference Ratio Evaluation Analysis Number 2019 Date Value Value (pCi/L) (pCi/L)

Milk Sr-89 E12361 2nd 7/29/19 1.01E+02 8.29E+01 1.22 Acceptable Sr-90 E12361 2nd 7/29/19 1.21E+01 1.35E+01 0.90 Acceptable I-131 E12362 2nd 7/29/19 8.51E+01 8.14E+01 1.05 Acceptable Ce-141 E12362 2nd 7/29/19 1.39E+02 1.33E+02 1.04 Acceptable Co-58 E12362 2nd 7/29/19 1.17E+02 1.12E+02 1.05 Acceptable Co-60 E12362 2nd 7/29/19 2.05E+02 1.98E+02 1.04 Acceptable Cr-51 E12362 2nd 7/29/19 3.41E+02 3.37E+02 1.01 Acceptable Cs-134 E12362 2nd 7/29/19 1.30E+02 1.40E+02 0.93 Acceptable Cs-137 E12362 2nd 7/29/19 1.78E+02 1.68E+02 1.06 Acceptable Mn-54 E12362 2nd 7/29/19 2.09E+02 1.90E+02 1.10 Acceptable Fe-59 E12362 2nd 7/29/19 1.66E+02 1.41E+02 1.18 Acceptable Zn-65 E12362 2nd 7/29/19 2.82E+02 2.47E+02 1.14 Acceptable Sample/ Radionuclide Sample Quarter Report GEL Reference Ratio Evaluation Analysis Number 2019 Date Value Value (pCi) (pCi)

Cartridge I-131 E12360 2nd 07/29/19 8.40E+01 8.17E+01 1.03 Acceptable TABLE A-3 (Continued)

GEL PARTICIPATION - INTERLABORATORY CROSS-CHECK PROGRAM DATA Sample/ Radionuclide Sample Quarter Report Date GEL Reference Ratio Evaluation Analysis Number 2018 Value Value (pCi/L) (pCi/L)

Gamma Water I-131 E12371 3rd 11/08/19 9.34E+01 8.94E+01 1.04 Acceptable Ce-141 E12371 3rd 11/08/19 1.41E+02 1.27E+02 1.11 Acceptable Cr-51 E12371 3rd 11/08/19 2.45E+02 2.51E+02 0.98 Acceptable Cs-134 E12371 3rd 11/08/19 1.50E+02 1.57E+02 0.96 Acceptable Cs-137 E12371 3rd 11/08/19 1.22E+02 1.14E+02 1.07 Acceptable Co-58 E12371 3rd 11/08/19 1.36E+02 1.33E+02 1.03 Acceptable Mn-54 E12371 3rd 11/08/19 1.34E+02 1.17E+02 1.15 Acceptable Fe-59 E12371 3rd 11/08/19 1.27E+02 1.12E+02 1.13 Acceptable Zn-65 E12371 3rd 11/08/19 2.57E+02 2.22E+02 1.16 Acceptable Co-60 E12371 3rd 11/08/19 1.68E+02 1.60E+02 1.036 Acceptable Sample/ Radionuclide Sample Quarter Report Date GEL Reference Ratio Evaluation Analysis Number 2019 Value Value (pCi/L) (pCi/L)

Milk I-131 E12370 3rd 11/08/19 9.28E+01 9.21E+01 1.01 Acceptable Sr-89 E12369 3rd 11/08/19 8.71E+01 9.39E+01 0.93 Acceptable Sr-90 E12369 3rd 11/08/19 7.02E+00 1.29E+01 0.54 Acceptable Ce-141 E12370 3rd 11/08/19 1.69E+02 1.67E+02 1.01 Acceptable Cr-51 E12370 3rd 11/08/19 3.64E+02 3.31E+02 1.1 Acceptable Cs-134 E12370 3rd 11/08/19 1.93E+02 2.07E+02 0.93 Acceptable Cs-137 E12370 3rd 11/08/19 1.49E+02 1.51E+02 0.99 Acceptable Co-58 E12370 3rd 11/08/19 1.74E+02 1.75E+02 0.99 Acceptable Mn-54 E12370 3rd 11/08/19 1.69E+02 1.54E+02 1.09 Acceptable Fe-59 E12370 3rd 11/08/19 1.66E+02 1.48E+02 1.12 Acceptable Zn-65 E12371 3rd 11/08/19 3.21E+02 2.93E+02 1.1 Acceptable Co-60 E12370 3rd 11/08/19 2.08E+02 2.11E+02 0.99 Acceptable Sample/ Radionuclide Sample Quarter Report Date GEL Reference Ratio Evaluation Analysis Number 2019 Value Value (pCi) (pCi)

Cartridge I-131 E12368 3rd 11/08/19 9.93E+01 9.33E+01 1.06 Acceptable TABLE A-3 (Continued)

GEL PARTICIPATION - INTERLABORATORY CROSS-CHECK PROGRAM DATA Sample/ Radionuclide Sample Quarter Report Date GEL Reference Ratio Evaluation Analysis Number 2019 Value Value (pCi/L) (pCi/L)

Gamma Water I-131 E12375 4th 02/05/20 1.04E+02 9.45E+01 1.10 Acceptable Ce-141 E12375 4th 02/05/20 8.92E+01 8.41E+01 1.06 Acceptable Cr-51 E12375 4th 02/05/20 2.64E+02 2.44E+02 1.08 Acceptable Cs-134 E12375 4th 02/05/20 1.06E+02 1.14E+02 0.93 Acceptable Cs-137 E12375 4th 02/05/20 1.09E+02 1.03E+02 1.06 Acceptable Co-58 E12375 4th 02/05/20 9.54E+01 9.11E+01 1.05 Acceptable Mn-54 E12375 4th 02/05/20 1.44E+02 1.31E+02 1.10 Acceptable Fe-59 E12375 4th 02/05/20 9.32E+01 8.82E+01 1.06 Acceptable Zn-65 E12375 4th 02/05/20 1.91E+02 1.61E+02 1.19 Acceptable Co-60 E12375 4th 02/05/20 1.22E+02 1.17E+02 1.05 Acceptable Sample/ Radionuclide Sample Quarter Report Date GEL Reference Ratio Evaluation Analysis Number 2018 Value Value (pCi/L) (pCi/L)

Milk Sr-89 E12373 4th 02/05/20 6.60E+01 8.06E+01 0.82 Acceptable Sr-90 E12373 4th 02/05/20 1.11E+01 1.10E+01 1.00 Acceptable I-131 E12374 4th 02/05/20 9.34E+01 9.45E+01 0.99 Acceptable Ce-141 E12374 4th 02/05/20 7.95E+01 8.30E+01 0.96 Acceptable Cr-51 E12374 4th 02/05/20 2.67E+02 2.41E+02 1.11 Acceptable Cs-134 E12374 4th 02/05/20 9.79E+01 1.13E+02 0.87 Acceptable Cs-137 E12374 4th 02/05/20 1.01E+02 1.02E+02 0.99 Acceptable Co-58 E12374 4th 02/05/20 8.93E+01 8.99E+01 0.99 Acceptable Mn-54 E12374 4th 02/05/20 1.34E+02 1.30E+02 1.03 Acceptable Fe-59 E12374 4th 02/05/20 1.01E+02 8.71E+01 1.16 Acceptable Zn-65 E12374 4th 02/05/20 1.71E+02 1.59E+02 1.08 Acceptable Co-60 E12374 4th 02/05/20 1.17E+02 1.15E+02 1.02 Acceptable Sample/ Radionuclide Sample Quarter Report Date GEL Reference Ratio Evaluation Analysis Number 2019 Value Value (pCi) (pCi)

Cartridge I-131 E12372 4th 02/05/20 9.07E+01 8.88E+01 1.02 Acceptable TABLE A-4 HBPP PARTICIPATION - ECKERT & ZIEGLER INTERLABORATORY CROSS-CHECK PROGRAM DATA Sample Radionuclide Sample Quarter Report HBPP Reference Ratio Evaluation Analysis Number 2019 Date (pCi/g) (pCi/g)

Gamma Soil Ce-141 E12544 1st 5/28/2019 7.23E-021 5.33E-02 1.361 Acceptable Detector 1 Co-58 E12544 1st 5/28/2019 1.37E-01 1.32E-01 1.04 Acceptable Co-60 E12544 1st 5/28/2019 4.90E-01 4.88E-01 1.00 Acceptable Cr-51 E12544 1st 5/28/2019 9.45E-02 1.06E-01 0.89 Acceptable Cs-134 E12544 1st 5/28/2019 2.50E-01 2.53E-01 0.99 Acceptable Cs-137 E12544 1st 5/28/2019 4.05E-01 4.01E-01 1.01 Acceptable Fe-59 E12544 1st 5/28/2019 1.07E-01 1.03E-01 1.04 Acceptable Mn-54 E12544 1st 5/28/2019 2.24E-01 2.09E-01 1.07 Acceptable Zn-65 E12544 1st 5/28/2019 2.95E-01 3.10E-01 0.95 Acceptable Sample Radionuclide Sample Quarter Report HBPP Reference Ratio Evaluation Analysis Number 2019 Date (pCi/g) (pCi/g)

Gamma Soil Ce-141 E12544 1st 5/28/2019 7.05E-021 5.33E-02 1.321 Acceptable Detector 3 Co-58 E12544 1st 5/28/2019 1.25E-01 1.32E-01 0.95 Acceptable Co-60 E12544 1st 5/28/2019 4.86E-01 4.88E-01 1.00 Acceptable Cr-51 E12544 1st 5/28/2019 9.60E-02 1.06E-01 0.90 Acceptable Cs-134 E12544 1st 5/28/2019 2.52E-01 2.53E-01 1.00 Acceptable Cs-137 E12544 1st 5/28/2019 4.03E-01 4.01E-01 1.00 Acceptable Fe-59 E12544 1st 5/28/2019 1.08E-01 1.03E-01 1.05 Acceptable Mn-54 E12544 1st 5/28/2019 2.29E-01 2.09E-01 1.10 Acceptable Zn-65 E12544 1st 5/28/2019 3.18E-01 3.10E-01 1.03 Acceptable Sample Radionuclide Sample Quarter Report HBPP Reference Ratio Evaluation Analysis Number 2019 Date (pCi/g) (pCi/g)

Gamma Soil Ce-141 E12544 1st 5/28/2019 6.97E-021 5.33E-02 1.311 Acceptable Det 0848 Co-58 E12544 1st 5/28/2019 1.34E-01 1.32E-01 1.02 Acceptable Co-60 E12544 1st 5/28/2019 4.67E-01 4.88E-01 0.96 Acceptable Cr-51 E12544 1st 5/28/2019 1.04E-01 1.06E-01 0.98 Acceptable Cs-134 E12544 1st 5/28/2019 2.52E-01 2.53E-01 1.00 Acceptable Cs-137 E12544 1st 5/28/2019 4.35E-01 4.01E-01 1.08 Acceptable Fe-59 E12544 1st 5/28/2019 1.02E-01 1.03E-01 0.99 Acceptable Mn-54 E12544 1st 5/28/2019 2.31E-01 2.09E-01 1.11 Acceptable Zn-65 E12544 1st 5/28/2019 3.08E-01 3.10E-01 0.99 Acceptable TABLE A-4 (Continued)

HBPP PARTICIPATION - ECKERT & ZIEGLER INTERLABORATORY CROSS-CHECK PROGRAM DATA Sample Radionuclide Sample Quarter Report HBPP Reference Ratio Evaluation Analysis Number 2019 Date (pCi/L) (pCi/L)

Gamma Soil Ce-141 E12544 1st 5/28/2019 6.41E-021 5.33E-02 1.20 Acceptable Detector 6 Co-58 E12544 1st 5/28/2019 1.34E-01 1.32E-01 1.02 Acceptable Co-60 E12544 1st 5/28/2019 4.87E-01 4.88E-01 1.00 Acceptable Cr-51 E12544 1st 5/28/2019 1.07E-01 1.06E-01 1.01 Acceptable Cs-134 E12544 1st 5/28/2019 2.50E-01 2.53E-01 0.99 Acceptable Cs-137 E12544 1st 5/28/2019 4.03E-01 4.01E-01 1.00 Acceptable Fe-59 E12544 1st 5/28/2019 1.04E-01 1.03E-01 1.01 Acceptable Mn-54 E12544 1st 5/28/2019 2.34E-01 2.09E-01 1.12 Acceptable Zn-65 E12544 1st 5/28/2019 3.16E-01 3.10E-01 1.02 Acceptable Sample Radionuclide Sample Quarter Report HBPP Reference Ratio Evaluation Analysis Number 2019 Date (pCi) (pCi)

Air Filter Gross Alpha E12545 2nd 6/25/2019 7.24E+01 6.76E+01 1.07 Acceptable Protean 7108 Gross Beta E12545 2nd 6/25/2019 2.26E+02 2.25E+02 1.00 Acceptable Sample Radionuclide Sample Quarter Report HBPP Reference Ratio Evaluation Analysis Number 2019 Date (pCi) (pCi)

Air Filter Gross Alpha E12545 2nd 6/25/2019 7.00E+01 6.76E+01 1.04 Acceptable Protean 7109 Gross Beta E12545 2nd 6/25/2019 2.30E+02 2.25E+02 1.02 Acceptable Sample Radionuclide Sample Quarter Report HBPP Reference Ratio Evaluation Analysis Number 2019 Date (pCi) (pCi)

Air Filter Gross Alpha E12545 2nd 6/25/2019 7.55E+01 6.76E+01 1.12 Acceptable Tennelec-1171 Gross Beta E12545 2nd 6/25/2019 2.23E+02 2.25E+02 0.99 Acceptable Sample/ Radionuclide Sample Quarter Report HBPP Reference Ratio Evaluation Analysis Number 2019 Date (pCi) (pCi)

Gamma Air Ce-141 E12546 2nd 6/25/2019 9.52E+01 8.82E+01 1.08 Acceptable Filter Co-58 E12546 2nd 6/25/2019 7.47E+01 7.41E+01 1.01 Acceptable Detector 1 Co-60 E12546 2nd 6/25/2019 1.35E+02 1.31E+02 1.03 Acceptable Cr-51 E12546 2nd 6/25/2019 2.24E+02 2.23E+02 1.00 Acceptable Cs-134 E12546 2nd 6/25/2019 8.45E+01 9.29E+01 0.91 Acceptable Cs-137 E12546 2nd 6/25/2019 1.15E+02 1.11E+02 1.03 Acceptable Fe-59 E12546 2nd 6/25/2019 1.06E+02 9.35E+01 1.13 Acceptable Mn-54 E12546 2nd 6/25/2019 1.33E+02 1.26E+02 1.06 Acceptable Zn-65 E12546 2nd 6/25/2019 1.80E+02 1.64E+02 1.10 Acceptable TABLE A-4 (Continued)

HBPP PARTICIPATION - ECKERT & ZIEGLER INTERLABORATORY CROSS-CHECK PROGRAM DATA Sample Radionuclide Sample Quarter Report HBPP Reference Ratio Evaluation Analysis Number 2019 Date (pCi) (pCi)

Gamma Air Ce-141 E12546 2nd 6/25/2019 8.46E+01 8.82E+01 0.96 Acceptable Filter Co-58 E12546 2nd 6/25/2019 7.31E+01 7.41E+01 0.99 Acceptable Detector 3 Co-60 E12546 2nd 6/25/2019 1.32E+02 1.31E+02 1.01 Acceptable Cr-51 E12546 2nd 6/25/2019 2.22E+02 2.23E+02 1.00 Acceptable Cs-134 E12546 2nd 6/25/2019 8.18E+01 9.29E+01 0.88 Acceptable Cs-137 E12546 2nd 6/25/2019 1.13E+02 1.11E+02 1.01 Acceptable Fe-59 E12546 2nd 6/25/2019 9.80E+01 9.35E+01 1.05 Acceptable Mn-54 E12546 2nd 6/25/2019 1.30E+02 1.26E+02 1.04 Acceptable Zn-65 E12546 2nd 6/25/2019 1.81E+02 1.64E+02 1.10 Acceptable Sample Radionuclide Sample Quarter Report HBPP Reference Ratio Evaluation Analysis Number 2019 Date (pCi/L) (pCi/L)

TriCarb Tritium (H3) E12547 3rd 09/12/19 3.61E+03 4.00E+03 0.90 Acceptable Sample/ Radionuclide Sample Quarter Report HBPP Reference Ratio Evaluation Analysis Number 2019 Date (pCi) (pCi)

Gamma Water Ce-141 E12548 3rd 09/12/19 1.28E+02 1.27E+02 1.01 Acceptable Detector 1 Co-58 E12548 3rd 09/12/19 1.25E+02 1.33E+02 0.94 Acceptable Co-60 E12548 3rd 09/12/19 1.58E+02 1.60E+02 0.99 Acceptable Cr-51 E12548 3rd 09/12/19 2.60E+02 2.51E+02 1.04 Acceptable Cs-134 E12548 3rd 09/12/19 1.40E+02 1.57E+02 0.89 Acceptable Cs-137 E12548 3rd 09/12/19 1.13E+02 1.14E+02 0.99 Acceptable Fe-59 E12548 3rd 09/12/19 1.13E+02 1.12E+02 1.00 Acceptable I-131 E12548 3rd 09/12/19 8.02E+01 8.99E+00 0.89 Acceptable Mn-54 E12548 3rd 09/12/19 1.19E+02 1.17E+02 1.02 Acceptable Zn-65 E12548 3rd 09/12/19 2.22E+02 2.22E+02 1.00 Acceptable TABLE A-4 (Continued)

HBPP PARTICIPATION - ECKERT & ZIEGLER INTERLABORATORY CROSS-CHECK PROGRAM DATA Sample Radionuclide Sample Quarter Report HBPP Reference Ratio Evaluation Analysis Number 2019 Date (pCi/L) (pCi/L)

Gamma Water Ce-141 E12548 3rd 09/12/19 1.26E+02 1.27E+02 1.00 Acceptable Detector 3 Co-58 E12548 3rd 09/12/19 1.38E+02 1.33E+02 1.04 Acceptable Co-60 E12548 3rd 09/12/19 1.60E+02 1.60E+02 1.00 Acceptable Cr-51 E12548 3rd 09/12/19 2.45E+02 2.51E+02 0.98 Acceptable Cs-134 E12548 3rd 09/12/19 1.41E+02 1.57E+02 0.90 Acceptable Cs-137 E12548 3rd 09/12/19 1.19E+02 1.14E+02 1.04 Acceptable Fe-59 E12548 3rd 09/12/19 1.20E+02 1.12E+02 1.07 Acceptable I-131 E12548 3rd 09/12/19 9.40E+01 8.99E+01 1.05 Acceptable Mn-54 E12548 3rd 09/12/19 1.20E+02 1.17E+02 1.03 Acceptable Zn-65 E12548 3rd 09/12/19 2.36E+02 2.22E+02 1.06 Acceptable Sample Radionuclide Sample Quarter Report HBPP Reference Ratio Evaluation Analysis Number 2019 Date (pCi) (pCi)

Gamma Water Ce-141 E12548 3rd 09/12/19 1.37E+02 1.27E+02 1.08 Acceptable Det 0848 Co-58 E12548 3rd 09/12/19 1.36E+02 1.33E+02 1.03 Acceptable Co-60 E12548 3rd 09/12/19 1.54E+02 1.60E+02 0.96 Acceptable Cr-51 E12548 3rd 09/12/19 2.79E+02 2.51E+02 1.11 Acceptable Cs-134 E12548 3rd 09/12/19 1.48E+02 1.57E+02 0.94 Acceptable Cs-137 E12548 3rd 09/12/19 1.22E+02 1.14E+02 1.07 Acceptable Fe-59 E12548 3rd 09/12/19 1.17E+02 1.12E+02 1.04 Acceptable I-131 E12548 3rd 09/12/19 9.89E+01 8.99E+01 1.10 Acceptable Mn-54 E12548 3rd 09/12/19 1.25E+02 1.17E+02 1.07 Acceptable Zn-65 E12548 3rd 09/12/19 2.31E+02 2.22E+01 1.04 Acceptable Table A-4 Notes:

1. Interlaboratory cross-checks for Quarter 1 of 2019 were not received within the first quarter due to a procurement problem. This was documented in corrective action SAPN 1452043. The gamma in soil cross-check was received in mid-May and was analyzed on Detectors 1, 3, 0848. and 6.

HBPP results were found to be acceptable in comparison with Eckert & Ziegler reported results with the exception of Ce-141, which was outside the agreement ratio range but was reported conservatively high. Ce-141 has a 32.5 day half-life and is not included as part of the known suite of radionuclides present at HBPP.

2. Analysis results based on 10-minute count times for alpha and beta analyses on Proteans SN 7108 and SN 7109, and Tennelec SN 1171. Alpha filter cross checks normally performed on each Protean gas flow proportional counter at count times of 5 minutes, 10 minutes, and 20 minutes. Beta filter cross checks normally performed on each Protean gas flow proportional counter at count times of 5 minutes and 10 minutes.

TABLE C-1 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANNUAL REPORT

SUMMARY

Name of Facility Humboldt Bay Power Plant Unit 3 Docket No. 50-133; License No. DPR-7 Location of Facility Humboldt County, California Reporting Period January 1 - December 31, 2019 (County, State)

Medium or Type and Lower Limit All Indicator Locations Location with Control Number Pathway Total of Detection Highest Annual Mean Locations of Non-Sampled Number of (LLD) routine

[Unit of Analyses Reported Measurement] Performed Mean, (Fraction), & [Range]b Name Mean, Mean, Measure-(Fraction) (Fraction) ments

& [Range]b & [Range]b (53) samples per Gross Beta East Fence (AM1) Annex Gross Alpha Humboldt Hill N/A AIRBORNE station 1.00E-02 Gross Alpha (pCi/m3) mean 2.76E-03, (7/35), [2.34E-03 to 3.59E-03] (AM3) (pCi/m3) mean (Station 3)

Gross Beta, pCi/m3 Gross Beta (pCi/m3) mean 8.99E-03, (32/35), [3.41E-03 to 1.88E-02] 3.03E-03, Gross Alpha Particulates Gross Alpha Building 12 (AM2) (13/45), (pCi/m3) mean Gamma Gamma Gross Alpha (pCi/m3) mean 2.43E-03, (14/53), [6.58E-03 to 8.37E-04] [1.41E-03 to 2.65E-03,

[pCi/m3] Isotopic Isotopic Gross Beta (pCi/m3) mean 1.05E-02, (49/53), [3.34E-03 to 2.73E-02] 5.07E-03] (6/53),

analysis on analysis on Annex (AM3) [1.35E-03 to quarterly quarterly Gross Alpha (pCi/m3) mean 3.03E-03, (13/45), [1.41E-03 to 5.07E-03] 4.01E-03]

composite (by composite Gross Beta (pCi/m3) mean 1.05E-02, (44/45), [3.26E-03 to 2.26E-02]

station) (by station) Relay Building (AM4) Relay Gross Beta Gross Alpha (pCi/m3) mean 2.35E-03, (14/53), [2.39E-03 to 6.05E-03] Bldg. Gross Beta (pCi/m3) mean (4) Onsitec Gross Beta (pCi/m3) mean 1.03E-02, (47/53), [8.28E-03 to 3.07E-02] (AM2) (pCi/m3) mean 7.46E-03, Cs-137 1.05E-02, (48/53),

Locations 6.00E-02 (49/53), [3.34E- [5.36E-03 to (1) Offsitec pCi/m3 03 to 2.73E-02] 1.72E-02]

Locations Cs-137 <MDA (63) Fence line 5 mRem Fence Line TLDs (T1 to T16) Station T1 (mR/qtr) Stations 1, 2, 0 DIRECT TLD readings 13.3 +/- 0.1, (63/63), [10.7 to 16.4] T-1, mean 14, 25 and T17 RADIATION Figure 15.7 0.3, (mR/qtr) mean

[mR/quarter] (20) Off-site TLD B-1 (4/4), [15.1 to 12.6 0.2, Readings 16.4] (20/20),

[10.8 to 15.1]

TABLE C-1 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANNUAL REPORT

SUMMARY

Type All Indicator Location with Highest Annual Mean Control Medium or and Total Lower Locations Locations Number of Pathway Sampled Number of Limit of Mean, Name, Mean, Mean, Non-routine

[Unit of Analyses Detection (Fraction) Distance and (Fraction) (Fraction) Reported Measurement] Performed (LLD) & [Range] b Direction & [Range] b & [Range] b Measurements 0

WATERBORNE Groundwater Not Required N/A N/A N/A N/A Not Required Not Required Drinking Water Not Required N/A N/A N/A N/A Not Required N/A Sediment Not Required N/A N/A N/A N/A Not Required N/A Algae Not Required N/A N/A N/A N/A Not Required N/A INGESTION Not Required N/A N/A N/A N/A Not Required N/A TERRESTRIAL Soil Not Required N/A N/A N/A N/A Not Required N/A a

The LLD is defined as the smallest concentration of radioactive material in a sample that will yield a net count, above system background, that will be detected with 95 percent probability with only 5 percent probability of falsely concluding that a blank observation represents a real signal.

LLD is defined as the a priori (before the fact) lower limit of detection (as pCi per unit mass or volume) representing the capability of a measurement system and not as the a posteriori (after the fact) limit for a particular measurement. (Current literature defines the LLD as the detection capability for the instrumentation only, and the MDA, minimum detectable concentration, as the detection capability for a given instrument, procedure and type of sample.) The actual MDA values for the radionuclide specific analyses were at or below the LLD.

b The mean and the range are based on detectable measurements only. The fraction of detectable measurements at specified locations is indicated in parentheses; e.g., (10/12) means that 10 out of 12 samples contained detectable activity. The range of detected results is indicated in brackets; e.g.,

[23 to 34].

c On 11/06/2019 air samplers Annex Building (AM3) and Humboldt Hill (Station 3) were turned off and removed from service. Number of onsite and offsite air sample locations reduced in ODCM Revision 30 & 31. Onsite air samplers reduced from four to two, offsite air samplers reduced from one to zero. In addition, beginning 4th Quarter all samples were sent to GEL for offsite analysis to facilitate demobilization of the onsite count room.

Not Required: Not required by the HBPP Unit 3 Technical Specifications or the SAFSTOR Offsite Dose Calculation Manual. Baseline environmental conditions for this parameter were established in the Environmental Report as referenced by the SAFSTOR Decommissioning Plan (now identified as the Post Shutdown Decommissioning Activities Report and Defueled Safety Analysis Report).

N/A - Not applicable TABLE C-2 ONSITE ENVIRONMENTAL TLD STATIONS Station TLD Exposure Measurements (mR)

Number First Quarter Second Quarter Third Quarter Fourth Quarter T1 15.3 +/- 0.1 15.1 +/- 0.2 16.4 +/- 0.7 16.1 +/- 0.2 T2 13.2 +/- 0.4 12.3 +/- 0.3 14.1 +/- 0.6 13.8 +/- 0.5 T3 13.1 +/- 0.1 11.8 +/- 0.3 13.4 +/- 0.2 13.2 +/- 0.7 T4 13.7 +/- 0.5 12.5 +/- 0.3 14.3 +/- 0.4 13.8 +/- 0.5 T5 12.6 +/- 0.1 11.4 +/- 0.3 12.6 +/- 0.3 12.8 +/- 0.2 T6 12.0 +/- 0.2 10.7 +/- 0.2 13.1 +/- 0.1 13.4 +/- 0.3 T7 11.8 +/- 0.4 10.7 +/- 0.1 13.2 +/- 0.3 14.5 +/- 1.2 T8 12.4 +/- 0.6 11.0 +/- 0.3 13.9 +/- 0.1 14.1 +/- 0.4 T9 13.6 +/- 0.5 11.7 +/- 0.1 13.0 +/- 0.2 12.9 +/- 0.7 T10 13.2 +/- 0.1 11.9 +/- 0.4 13.2 +/- 0.1 12.6 +/- 0.6 T11 14.2 +/- 0.0 14.4 +/- 0.2 15.6 +/- 0.0 15.5 +/- 0.3 T12 12.8 +/- 0.3 12.3 +/- 0.4 13.8 +/- 1.0 13.7 +/- 0.3 T13 13.1 +/- 0.1 12.7 +/- 0.1 13.7 +/- 1.0 14.0 +/- 0.4 T14 13.6 +/- 0.2 12.8 +/- 0.2 14.4 +/- 0.2 14.6 +/- 0.5 T15 12.9 +/- 0.4 12.4 +/- 0.3 13.6 +/- 0.9 14.4 +/- 1.7 T16 12.8 +/- 0.5 12.3 +/- 0.2 13.7 +/- 0.2 13.9 +/- 0.3 Calculated Parameters (mR)

Parameter First Quarter Second Quarter Third Quarter Fourth Quarter Average 13.1 +/- 0.1 12.3 +/- 0.1 13.9 +/- 0.1 14.0 +/- 0.2 Maximum 15.3 +/- 0.1 15.1 +/- 0.2 16.4 +/- 0.2 16.1 +/- 0.2 Table C-2 Notes:

1. Offsite TLD Station 1 was moved approximately 20 feet on January 30, 2019, to allow cutting of vegetation and removal of fencing. This is documented in corrective action SAPN 1450240.

2. Two anomalies were reported in the 2019 Q1 TLD Report from Mirion.

Three TLDs are installed at each station, with each TLD containing 3 crystal elements. The reported TLD results is based on an average of the 9 elements at each location. T-8A registered exposures of 14 mR, 12 mR, and 135 mR. T-8B displayed 12 mR, 11 mR, and 12 mR while T-8C showed measurements of 12 mR, 13 mR, and 13 mR. The high measurement of 135 mR was discarded as not valid. T-9A had readings of 14 mR, 14 mR, and 13 mR, while T-9B displayed measurements of 35 mR, 13 mR, and 13 mR. T-9C showed readings of 14 mR, 14 mR, and 14 mR. The 35 mR measurement also appeared to be an anomaly and was discarded from the average at this location. This was documented in corrective action SAPN 1453104.

3. Onsite TLD locations T-9 and T-10 were relocated to permanent fencing along RCA Way on May 3, 2019. This is documented in corrective action SAPN 1450240.

4. Onsite TLD location T-8 was retrieved from the field on May 9, 2019, because of planned remediation of an environmental area within the immediate vicinity. Onsite TLD location T-7 was also retrieved from the field on May 20, 2019 due to expansion of the environmental remediation.

Both T-7 and T-8 were installed on permanent plant fencing at the site perimeter on July 25, 2019. This is documented in corrective action SAPN 1450240.

5. Onsite TLD location T-6 was retrieved from the field on June 13, 2019, because of further environmental remediation along the plant fence line.

T-6 was installed on permanent plant fencing at the site perimeter on July 25, 2019. This is documented in corrective action SAPN 1450240.

6. Onsite TLD location T-5 was retrieved from the field on June 27, 2019, because of further environmental remediation along the plant fence line.

T-5 was installed on the ISFSI fence on July 25, 2019. This is documented in corrective action SAPN 1450240.

7. Onsite TLD location T-11 was relocated on August 7, 2019, from the East Fence dog house air sampler to permanent fence directly across from the air sampler. The air sampler is scheduled to be discontinued due to electrical power issues. This is documented in corrective action SAPN 1450240.

8. These exposures are reported for a standardized period of 90 days.

9. The reported exposures do not have an average background or transient dose subtracted.

TABLE C-3 OFFSITE (Control) ENVIRONMENTAL TLD STATIONS Station TLD Exposure Measurements (mR)

Number First Quarter Second Quarter Third Quarter Fourth Quarter 1 12.4 +/- 0.0 11.7 +/- 0.3 13.5 +/- 0.2 12.9 +/- 0.8 2 14.2 +/- 0.3 13.4 +/- 0.1 15.1 +/- 0.0 14.9 +/- 0.4 14 11.6 +/- 0.8 10.8 +/- 1.1 12.6 +/- 0.3 12.2 +/- 0.7 25 11.8 +/- 0.2 11.1 +/- 0.4 12.8 +/- 0.3 12.8 +/- 0.7 T17 11.8 +/- 0.2 11.2 +/- 0.1 12.5 +/- 0.2 12.6 +/- 0.1 Calculated Parameters (mR)

Parameter First Quarter Second Quarter Third Quarter Fourth Quarter Average 12.4 +/- 0.2 11.6 +/- 0.2 13.3 +/- 0.1 13.1 +/- 0.3 Maximum 14.2 +/-0.3 13.4 +/- 0.1 15.1 +/- 0.0 14.9 +/- 0.4 Table C-3 Notes:

1. These exposures are reported for a standardized period of 90 days.

Table C-4 ODCM REQUIRED AIR SAMPLES: EAST FENCE (AM1)

Sample Alpha Activity Beta Activity Composite Gamma Start Date (pCi/m3) (pCi/m3) Activity (pCi/m3)

Co-60 Cs-137 12/26/2018 < 3.40E-03 (MDA) 7.59E-03 +/- 3.54E-03 1/2/2019 < 3.58E-03 (MDA) 3.93E-03 +/- 3.13E-03 1/9/2019 < 3.45E-03 (MDA) 1.62E-02 +/- 4.60E-03 1/16/2019 < 3.49E-03 (MDA) < 6.05E-03 (MDA) 1/23/2019 2.34E-03 +/- 1.85E-03 1.88E-02 +/- 4.76E-03 1/30/2019 < 3.25E-03 (MDA) 7.07E-03 +/- 3.35E-03 2/6/2019 3.59E-03 +/- 2.34E-03 1.21E-02 +/- 4.09E-03 <2.05E-03 < 2.49E-03 2/13/2019 < 3.32E-03 (MDA) 6.16E-03 +/- 3.27E-03 (MDA) (MDA) 2/20/2019 < 3.43E-03 (MDA) 3.41E-03 +/- 2.95E-03 2/27/2019 < 3.50E-03 (MDA) 1.14E-02 +/- 4.10E-03 3/6/2019 < 3.49E-03 (MDA) 1.07E-02 +/- 4.01E-03 3/13/2019 < 3.46E-03 (MDA) 1.52E-02 +/- 4.49E-03 3/20/2019 < 3.40E-03 (MDA) 6.89E-03 +/- 3.45E-03 3/27/2019 < 3.31E-03 (MDA) 9.67E-03 +/- 3.75E-03 4/3/2019 < 3.24E-03 (MDA) 6.02E-03 +/- 3.19E-03 4/10/2019 < 3.48E-03 (MDA) < 6.03E-03 (MDA) 4/17/2019 < 3.58E-03 (MDA) 1.13E-02 +/- 4.15E-03 4/24/2019 < 3.39E-03 (MDA) 1.42E-02 +/- 4.33E-03 5/1/2019 3.12E-03 +/- 2.23E-03 1.05E-02 +/- 4.03E-03 5/8/2019 < 3.47E-03 (MDA) 7.74E-03 +/- 3.61E-03

< 2.96E-03 < 2.12E-03 5/15/2019 < 3.48E-03 (MDA) 5.25E-03 +/- 3.26E-03 (MDA) (MDA) 5/22/2019 < 3.41E-03 (MDA) 6.91E-03 +/- 3.47E-03 5/29/2019 3.00E-03 +/- 2.14E-03 3.77E-03 +/- 2.96E-03 6/5/2019 2.38E-03 +/- 1.88E-03 1.45E-02 +/- 4.35E-03 6/12/2019 2.49E-03 +/- 1.96E-03 5.70E-03 +/- 3.37E-03 6/19/2019 < 3.31E-03 (MDA) 5.10E-03 +/- 3.10E-03 6/26/2019 < 3.42E-03 (MDA) 9.40E-03 +/- 3.79E-03 7/3/2019 < 3.39E-03 (MDA) 9.90E-03 +/- 3.84E-03 7/10/2019 < 3.48E-03 (MDA) 5.97E-03 +/- 3.37E-03 7/17/2019 < 3.37E-03 (MDA) < 5.84E-03 (MDA) 7/24/2019 < 3.48E-03 (MDA) 8.13E-03 +/- 3.68E-03 <3.26E-04 <3.06E-04 7/31/2019 < 3.57E-03 (MDA) 9.45E-03 +/- 3.92E-03 (MDA) (MDA) 8/7/2019 2.37E-03 +/- 1.88E-03 1.20E-02 +/- 4.07E-03 8/14/2019 < 3.47E-03 (MDA) 7.75E-03 +/- 3.61E-03 8/21/2019 < 3.60E-03 (MDA)4 5.06E-03 +/- 3.32E-034 Table C-4 (Continued)

ODCM REQUIRED AIR SAMPLES: AM2 NORTH (AM2)

Table C-4 (Continued)

ODCM REQUIRED AIR SAMPLES: ANNEX BUILDING (AM3)

Sample Alpha Activity Beta Activity Composite Gamma Start Date (pCi/m3) (pCi/m3) Activity (pCi/m3)

Co-60 Cs-137 12/26/2018 < 3.39E-03 (MDA) 7.22E-03 +/- 3.48E-03 1/2/2019 < 3.58E-03 (MDA) 1.02E-02 +/- 4.02E-03 1/9/2019 < 3.45E-03 (MDA) 9.49E-03 +/- 3.83E-03 1/16/2019 < 3.49E-03 (MDA) 8.52E-03 +/- 3.73E-03 1/23/2019 2.34E-03 +/- 1.85E-03 2.26E-02 +/- 5.13E-03 1/30/2019 2.88E-03 +/- 2.05E-03 1.05E-02 +/- 3.80E-03 2/6/2019 < 3.38E-03 (MDA) 1.57E-02 +/- 4.50E-03 <2.59E-03 < 2.66E-03 2/13/2019 < 3.32E-03 (MDA) 1.18E-02 +/- 4.01E-03 (MDA) (MDA) 2/20/2019 < 3.43E-03 (MDA) 6.95E-03 +/- 3.48E-03 2/27/2019 2.47E-03 +/- 1.95E-03 1.68E-02 +/- 4.71E-03 3/6/2019 < 3.49E-03 (MDA) 1.14E-02 +/- 4.08E-03 3/13/2019 < 3.46E-03 (MDA) 1.73E-02 +/- 4.72E-03 3/20/2019 < 3.40E-03 (MDA) 1.14E-02 +/- 4.03E-03 3/27/2019 4.14E-03 +/- 2.49E-03 9.78E-03 +/- 3.79E-03 4/3/2019 < 3.24E-03 (MDA) 3.26E-03 +/- 2.76E-03 4/10/2019 < 3.47E-03 (MDA) 7.40E-03 +/- 3.56E-03 4/17/2019 < 3.58E-03 (MDA) 1.39E-02 +/- 4.44E-03 4/24/2019 < 3.39E-03 (MDA) 1.80E-02 +/- 4.73E-03 5/1/2019 < 3.56E-03 (MDA) 1.09E-02 +/- 4.09E-03 5/8/2019 3.05E-03 +/- 2.17E-03 7.38E-03 +/- 3.56E-03

< 2.58E-03 < 3.08E-03 5/15/2019 < 3.48E-03 (MDA) 7.77E-03 +/- 3.63E-03 (MDA) (MDA) 5/22/2019 < 3.41E-03 (MDA) 9.01E-03 +/- 3.74E-03 5/29/2019 < 3.39E-03 (MDA) 7.38E-03 +/- 3.50E-03 6/5/2019 < 3.38E-03 (MDA) 1.03E-02 +/- 3.88E-03 6/12/2019 < 3.53E-03 (MDA) < 6.11E-03 (MDA) 6/19/2019 3.52E-03 +/- 2.29E-03 9.33E-03 +/- 3.70E-03 6/26/2019 < 3.42E-03 (MDA) 7.99E-03 +/- 3.61E-03 7/3/2019 < 3.39E-03 (MDA) 5.57E-03 +/- 3.23E-03 7/10/2019 < 3.48E-03 (MDA) 5.25E-03 +/- 3.26E-03 7/17/2019 < 3.37E-03 (MDA) 6.83E-03 +/- 3.42E-03 7/24/2019 2.45E-03 +/- 1.94E-03 4.54E-03 +/- 3.16E-03 7/31/2019 < 3.57E-03 (MDA) 1.20E-02 +/- 4.24E-03 8/7/2019 < 3.37E-03 (MDA) 1.34E-02 +/- 4.22E-03

<2.59E-04 <2.32E-04 8/14/2019 < 3.47E-03 (MDA) 1.20E-02 +/- 4.15E-03 (MDA) (MDA) 8/21/2019 2.53E-03 +/- 2.00E-03 8.40E-03 +/- 3.80E-03 8/28/2019 < 3.35E-03 (MDA) 9.88E-03 +/- 3.79E-03 9/4/2019 < 3.54E-03 (MDA) 1.52E-02 +/- 4.56E-03 9/11/2019 < 3.51E-03 (MDA) 4.58E-03 +/- 3.19E-03 9/18/2019 < 3.37E-03 (MDA) 9.95E-03 +/- 3.82E-03 9/25/2019 < 3.56E-03 (MDA) 1.09E-02 +/- 4.01E-03 10/2/2019 2.40E-03 +/- 1.17E-03 1.36E-02 +/- 1.83E-03 10/09/2019 5.07E-03 +/- 1.57E-03 1.72E-02 +/- 2.01E-03

<1.05E-03 <9.96E-04 10/16/2019 1.64E-03 +/- 9.48E-04 1.01E-02 +/- 1.58E-03 (MDA) (MDA) 10/23/2019 1.41E-03 +/- 9.62E-04 1.24E-02 +/- 1.181E-03 10/30/2019 4.06E-03 +/- 1.19E-03 2.17E-02 +/- 2.01E-03 Table C-4 (Continued)

ODCM REQUIRED AIR SAMPLES: RELAY BUILDING (AM4)

Sample Alpha Activity Beta Activity Composite Gamma Start Date (pCi/m3) (pCi/m3) Activity (pCi/m3)

Co-60 Cs-137 12/26/2018 2.39E-03 +/- 1.89E-03 8.28E-03 +/- 3.62E-03 1/2/2019 < 3.58E-03 (MDA) 1.31E-02 +/- 4.37E-03 1/9/2019 < 3.45E-03 (MDA) 1.20E-02 +/- 4.13E-03 1/16/2019 < 3.49E-03 (MDA) < 6.05E-03 (MDA) 1/23/2019 < 3.30E-03 (MDA) 1.42E-02 +/- 4.27E-03 1/30/2019 < 3.25E-03 (MDA) 9.84E-03 +/- 3.72E-03 2/6/2019 < 3.38E-03 (MDA) 9.53E-03 +/- 3.78E-03 <3.00E-03 < 2.95E-03 2/13/2019 < 3.32E-03 (MDA) < 5.74E-03 (MDA) (MDA) (MDA) 2/20/2019 < 3.43E-03 (MDA) < 5.94E-03 (MDA) 2/27/2019 < 3.50E-03 (MDA) 1.21E-02 +/- 4.19E-03 3/6/2019 < 3.49E-03 (MDA) 7.07E-03 +/- 3.54E-03 3/13/2019 < 3.46E-03 (MDA) 1.24E-02 +/- 4.17E-03 3/20/2019 < 3.40E-03 (MDA) 8.99E-03 +/- 3.73E-03 3/27/2019 < 3.34E-03 (MDA) 4.08E-03 +/- 2.97E-03 4/3/2019 < 3.24E-03 (MDA) 5.67E-03 +/- 3.14E-03 4/10/2019 < 3.48E-03 (MDA) 5.61E-03 +/- 3.32E-03 4/17/2019 < 3.58E-03 (MDA) 1.28E-02 +/- 4.31E-03 4/24/2019 < 3.39E-03 (MDA) 1.14E-02 +/- 4.01E-03 5/1/2019 < 3.56E-03 (MDA) 8.67E-03 +/- 3.79E-03 5/8/2019 < 3.47E-03 (MDA) 7.74E-03 +/- 3.61E-03

< 8.61E-04 < 3.44E-03 5/15/2019 2.45E-03 +/- 1.94E-03 < 6.03E-03 (MDA)

(MDA) (MDA) 5/22/2019 < 3.41E-03 (MDA) 8.67E-03 +/- 3.69E-03 5/29/2019 < 3.39E-03 (MDA) 7.74E-03 +/- 3.55E-03 6/5/2019 2.38E-03 +/- 1.88E-03 5.10E-03 +/- 3.17E-03 6/12/2019 < 3.53E-03 (MDA) < 6.11E-03 (MDA) 6/19/2019 < 3.31E-03 (MDA) 6.16E-03 +/- 3.26E-03 6/26/2019 < 3.42E-03 (MDA) 3.41E-03 +/- 2.95E-03 7/3/2019 < 3.39E-03 (MDA) 7.38E-03 +/- 3.50E-03 7/10/2019 < 3.48E-03 (MDA) < 6.02E-03 (MDA) 7/17/2019 < 3.37E-03 (MDA) 6.48E-03 +/- 3.37E-03 7/24/2019 < 3.48E-03 (MDA) 6.70E-03 +/- 3.48E-03 7/31/2019 < 3.57E-03 (MDA) 1.06E-02 +/- 4.05E-03 8/7/2019 < 3.37E-03 (MDA) 1.38E-02 +/- 4.27E-03

<2.05E-04 <1.91E-04 8/14/2019 < 3.47E-03 (MDA) 6.32E-03 +/- 3.42E-03 (MDA) (MDA) 8/21/2019 < 3.60E-03 (MDA) 1.43E-02 +/- 4.50E-03 8/28/2019 < 3.35E-03 (MDA) 6.43E-03 +/- 3.35E-03 9/4/2019 2.49E-03 +/- 1.97E-03 8.62E-03 +/- 3.77E-03 9/11/2019 < 3.52E-03 (MDA) 1.04E-02 +/- 3.99E-03 9/18/2019 < 3.37E-03 (MDA) 4.74E-03 +/- 3.11E-03 9/25/2019 < 3.56E-03 (MDA) 1.38E-02 +/- 4.42E-03 10/2/2019 2.72E-03 +/- 1.11E-03 1.21E-02 +/- 1.70E-03 10/9/2019 2.38E-03 +/- 1.04E-03 1.50E-02 +/- 1.89E-03 10/16/2019 3.24E-04 +/- 4.83E-04 7.89E-03 +/- 1.48E-03 10/23/2019 1.40E-03 +/- 8.00E-04 1.49E-02 +/- 1.80E-03 10/30/2019 5.48E-03 +/- 1.64E-03 3.07E-02 +/- 2.81E-03 11/06/2019 6.05E-03 +/- 1.61E-03 2.75E-02 +/- 2.40E-03

<2.98E-04 <2.21E-04 11/13/2019 1.39E-03 +/- 9.91E-04 1.32E-02 +/- 1.77E-03 (MDA) (MDA) 11/20/2019 1.23E-03 +/- 8.07E-04 1.91E-02 +/- 2.04E-03 11/27/2019 1.13E-03 +/- 7.78E-04 8.94E-03 +/- 1.50E-03 12/04/2019 <6.76E-04 (MDA) 5.88E-03 +/- 1.15E-03 12/12/2019 <1.01E-03 (MDA) 8.18E-03 +/- 1.46E-03 12/17/2019 1.08E-03 +/- 7.37E-04 7.56E-03 +/- 1.28E-03 12/26/2019 <7.34E-04 1.07E-02 +/- 1.53E-03 Table C-4 (Continued)

ODCM REQUIRED AIR SAMPLES: HUMBOLDT HILL (STATION 3)

Sample Alpha Activity Beta Activity Composite Gamma Start Date (pCi/m3) (pCi/m3) Activity (pCi/m3)

Co-60 Cs-137 12/26/2018 < 3.37E-03 (MDA) 5.43E-03 +/- 3.21E-03 1/2/2019 < 3.54E-03 (MDA) 1.12E-02 +/- 4.10E-03 1/9/2019 < 3.47E-03 (MDA) 7.39E-03 +/- 3.56E-03 1/16/2019 < 3.47E-03 (MDA) 4.53E-03 +/- 3.15E-03 1/23/2019 < 6.88E-03 (MDA)1 1.57E-02 +/- 7.22E-031 1/30/2019 < 3.31E-03 (MDA) 4.74E-03 +/- 3.05E-03 2/6/2019 < 3.31E-03 (MDA) 9.67E-03 +/- 3.75E-03 < 3.08E-03 < 2.77E-03 2/13/2019 < 3.30E-03 (MDA) 8.24E-03 +/- 3.55E-03 (MDA) (MDA) 2/20/2019 < 3.47E-03 (MDA) < 6.00E-03 (MDA) 2/27/2019 < 3.48E-03 (MDA) 9.56E-03 +/- 3.86E-03 3/6/2019 < 3.44E-03 (MDA) 3.42E-03 +/- 2.96E-03 3/13/2019 < 3.47E-03 (MDA) 1.20E-02 +/- 4.15E-03 3/20/2019 < 3.47E-03 (MDA) 4.53E-03 +/- 3.15E-03 3/27/2019 2.93E-03 +/- 2.09E-03 < 5.72E-03 (MDA) 4/3/2019 < 3.28E-03 (MDA) 4.70E-03 +/- 3.02E-03 4/10/2019 < 3.49E-03 (MDA) < 6.04E-03 (MDA) 4/17/2019 < 3.56E-03 (MDA) 8.32E-03 +/- 3.76E-03 4/24/2019 < 3.40E-03 (MDA) 1.32E-02 +/- 4.22E-03 5/1/2019 < 3.57E-03 (MDA) 7.60E-03 +/- 3.66E-03 5/8/2019 < 3.47E-03 (MDA) < 6.01E-03 (MDA)

< 2.65E-03 < 2.55E-03 5/15/2019 < 3.43E-03 (MDA) 5.54E-03 +/- 3.28E-03 (MDA) (MDA) 5/22/2019 < 3.44E-03 (MDA) 4.49E-03 +/- 3.12E-03 5/29/2019 2.35E-03 +/- 1.85E-03 6.14E-03 +/- 3.25E-03 6/5/2019 < 3.50E-03 (MDA) 1.25E-02 +/- 4.23E-03 6/12/2019 < 4.92E-03 (MDA) 5.40E-03 +/- 4.31E-03 6/19/2019 < 3.35E-03 (MDA)3 4.09E-03 +/- 2.98E-033 6/26/2019 2.40E-03 +/- 1.90E-03 4.10E-03 +/- 3.04E-03 7/3/2019 3.61E-03 +/- 2.36E-03 5.60E-03 +/- 3.24E-03 7/10/2019 2.45E-03 +/- 1.94E-03 < 6.02E-03 (MDA) 7/17/2019 < 3.42E-03 (MDA) 6.22E-03 +/- 3.37E-03 7/24/2019 < 3.48E-03 (MDA) 3.46E-03 +/- 3.00E-03 7/31/2019 < 3.58E-03 (MDA) 8.36E-03 +/- 3.78E-03 8/7/2019 < 3.36E-03 (MDA) 7.49E-03 +/- 3.49E-03

<2.58E-04 <3.32E-04 8/14/2019 < 3.43E-03 (MDA) 8.01E-03 +/- 3.62E-03 (MDA) (MDA) 8/21/2019 < 3.64E-03 (MDA) 6.63E-03 +/- 3.59E-03 8/28/2019 < 3.37E-03 (MDA) 1.03E-02 +/- 3.87E-03 9/4/2019 < 3.44E-03 (MDA) 4.13E-03 +/- 3.07E-03 9/11/2019 < 3.53E-03 (MDA) 8.97E-03 +/- 3.82E-03 9/18/2019 < 3.43E-03 (MDA) 4.12E-03 +/- 3.06E-03 9/25/2019 2.38E-03 +/- 1.88E-03 3.36E-03 +/- 2.91E-03 10/2/2019 1.78E-03 +/- 9.43E-04 1.04E-02 +/- 1.56E-03 10/9/2019 4.01E-03 +/- 1.30E-03 1.46E-02 +/- 1.89E-03

<8.67E-04 <6.82E-04 10/16/2019 1.35E-03 +/- 8.71E-04 5.36E-03 +/- 1.41E-03 (MDA) (MDA) 10/23/2019 2.17E-03 +/- 1.03E-03 1.11E-02 +/- 1.70E-03 10/30/2019 3.76E-03 +/- 1.20E-03 1.72E-02 +/- 1.83E-03 Table C-4 Notes

1. The REMP air sampler at Humboldt Hill was found to be not operating on January 30, 2019, after approximately 95 hours0.0011 days <br />0.0264 hours <br />1.570767e-4 weeks <br />3.61475e-5 months <br /> of run time. The GFCI was tripped, causing the air sampler to shut down prematurely. This is described in corrective action SAPN 1450240. The totalizer reading was used to calculate sample volume and resulting sample activity.

2. AM-2 was moved from GWTS 2.0 to the road adjacent to the ISFSI on May 1, 2019. Due to the shutdown and dismantlement of GWTS, electrical power to the air sampler was scheduled to be discontinued. The air sampler was turned off for approximately 20 minutes during the relocation. This is described in corrective action SAPN 1450240.

3. On June 25, 2019, the REMP air sampler at Humboldt Hill was found to be not operating after approximately 118 hours0.00137 days <br />0.0328 hours <br />1.951058e-4 weeks <br />4.4899e-5 months <br /> on the totalizer. Electrical power to the air sampler may have been shut down to allow grass trimming around the perimeter of the air sample station. This is described in corrective action SAPN 1450240.

4. On August 28, 2019, the REMP air sampler at the East Fence (AM1) was turned off and removed from service. The ODCM was revised to reflect the elimination of AM1 on the eastern perimeter fence line and the change from 4 onsite air sampling locations to 3. This is documented in corrective action SAPN 1450240.

5. On November 6, 2019, air samplers Annex Building (AM3) and Humboldt Hill (Station 3) were turned off and removed from service. The ODCM was revised to reflect the elimination of AM3 and Station 3 and change from 3 onsite air sampling locations to 2. This is documented in corrective action SAPN 1450240.

6. To facilitate demobilization and survey of HBPP onsite count room building and equipment, beginning fourth quarter 2019, all air samples were sent to GEL for sample analysis.

FIGURE A-1 HBPP ONSITE AIR SAMPLE LOCATIONS Location GPS Coordinates (NAD83/NAVD88 CA. Zone 1)

Number Easting Northing East Fence 5949844 2161231 AM1 GWTS 59498846 2161067 AM2 Annex Bldg.

5949178 2160817 AM3 Relay Bldg.

5949456 2160858 AM4 Figure A-1 Note:

1. Humboldt Hill (Offsite) is also known as Station 3, East Fence is also known as AM1, GWTS (formerly Building 12) is also known as AM2, Annex is also known as AM3, and the Relay Building is also known as AM4.

2. AM1 was powered down and removed from service on August 28, 2019.

The change in the number of onsite air samplers was reflected in ODCM Revision 30 and corrective action SAPN 1450240.

3. ]AM3, was powered down and removed from service on November 6, 2019. The change in the number of onsite air samplers was reflected in ODCM Revision 31 as noted in corrective action SAPN 1459240.

FIGURE A-2 HBPP OFFSITE AIR SAMPLE LOCATION HUMBOLDT HILL (Station 3)

Offsite Air Sampler Station 3

1. Offsite air sampler, also known as Humboldt Hill (Station 3), was powered down and removed from service on November 6, 2019. The change in the number of onsite air samplers was reflected in ODCM Revision 31 as noted in corrective action SAPN 1459240.

FIGURE A-3 HBPP ONSITE TLD LOCATIONS Stations T1 - T16 (excluding T17)

T-8 T-7 T-6 T-5 T-9 T-4 T-10 T-11 T-3 T-2 T-1 T-12 T-16 T-14 T-13 T-15 Monitoring Locations T7, T10, T11, T13, T16, T2, T3, and T5 generally represent REMP Site Boundary direct exposure monitoring locations in the 8 primary compass points beginning with T7 representing north and moving clockwise.

Location GPS Coordinates Number (NAD83/NAVD88 CA Zone 1)

Easting Northing Elevation T1 5949179 2160815 11 T2 5948794 2160911 17 T3 5948610 2161062 42 T4 5948779 2161270 44 T5 5948944 2161301 40 T6 5949140 2161433 36 T7 5949249 2161482 33 T8 5949428 2161435 28 T9 5949478 2161241 23 T10 5949519 2161199 19 T11 5949772 2161202 13 T12 5950019 2160858 11 T13 5949842 2160718 10 T14 5949584 2160684 10 T15 5949473 2160590 11 T16 5949327 2160771 11 FIGURE A-4 HBPP OFFSITE TLD LOCATIONS Stations (1, 14 & 25)

FIGURE A-4 (Continued)

HBPP OFFSITE TLD LOCATION FORTUNA (Station 2)

FIGURE A-4 (Continued)

HBPP OFFSITE TLD LOCATION EUREKA (Control Location T17)

FIGURE B-1 OFFSITE ENVIRONMENTAL RADIATION LEVEL TRENDS 80.0 70.0 60.0 50.0 Dose mRem/yr 40.0 King Salmon Picnic Acea (Station1) 30.0 Fortuna (Station 2) 20.0 South Bay School (Station 14)

Humboldt Hill (Station 25) 10.0 Myrtletown Substation (Station T17) 0.0 Year The baseline values for each location were obtained by averaging the readings at each location from 1977 through 1983. These values, however, were obtained using ion chambers instead of TLDs. The average annual values from 1977 through 1983 were Station 1 - 83.0 mRem, Station 2 - 79.8 mRem, Station 14 - 80.2 mRem, and Station 25 -

73.7 mRem.

70.0 FIGURE B-2 60.0 ONSITE ENVIRONMENTAL RADIATION LEVEL TRENDS 50.0 40.0 30.0 Stations Near Radwaste Activities (T5T8), 19892015 Other Onsite Stations (T1T4, T9T16), 19892015 20.0 Radwaste handling (T8T10), 20162019 Other Onsite Stations (T1T7, T11T16) 20162019 10.0 0.0 Year The baseline values for the two areas were obtained by averaging the readings for each area from 1977 through 1983. These values, however, were obtained using ion chambers instead of TLDs. The average annual value from 1977 through 1983 for the stations near the radwaste activities was 78.6 mRem and the average annual value for other onsite stations was 79.4 mRem.