RS-24-052, 2023 Annual Radiological Environmental Operating Report
| ML24136A112 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 05/15/2024 |
| From: | Humphrey M Constellation Energy Generation |
| To: | Office of Nuclear Material Safety and Safeguards, Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| RS-24-052 | |
| Download: ML24136A112 (1) | |
Text
4300 Winfield Road Warrenville, IL 60555 630 657 2000 Office RS-24-052 May 15, 2024 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Zion Nuclear Power Station, Units 1 and 2 Facility Operating License Nos. DPR-39 and DPR-48 NRC Docket Nos. 50-295, 50-304 and 72-1037
Subject:
Zion Nuclear Power Station 2023 Annual Radiological Environmental Operating Report
Reference:
Letter from A. M. Snyder (U.S. NRC) to D. P. Rhoades (Constellation Energy Generation, LLC) and J. Sauger (EnergySolutions, LLC), "Issuance of Conforming Amendments Regarding Direct Transfer of DPR-39 and DPR-48 Facility Operating Licenses from ZionSolutions, LLC to Constellation Energy Generation, LLC (EPID-L-2023-LLN-0003)," dated November 16, 2023 In the Reference, the NRC issued conforming amendments for Zion Nuclear Power Station (ZNPS), Units 1 and 2, to reflect the direct transfers of the ZNPS licenses from ZionSolutions, LLC (ZS) to Constellation Energy Generation, LLC (CEG). The conforming amendments became effective on November 16, 2023, when the direct license transfer was consummated.
In accordance with the CEG Decommissioning Quality Assurance Program (DQAP),
Appendix F, "Zion Specific Administrative Requirements," CEG is submitting the 2023 Annual Radiological Environmental Operating Report (AREOR) for Zion Nuclear Power Station, Units 1 and 2. The DQAP requires the AREOR, covering the plant activities during the previous calendar year, to be submitted by May 15 of each year. However, due to the license transfer discussed above, the 2023 AREOR is being submitted as follows.
- provides the AREOR that was developed by ZS and includes radiological information covering the period when ZS was the licensee of ZNPS (i.e., from January 1, 2023, through November 16, 2023). CEG is submitting Attachment 1 on behalf of ZS.
- provides the AREOR covering the period from November 17, 2023, through December 31, 2023. CEG began operations at ZNPS on November 17, 2023.
May 15, 2024 U.S. Nuclear Regulatory Commission Page 2 There are no regulatory commitments contained in this letter. Should you have any questions concerning this letter, please contact Kenneth M. Nicely at (779) 231-6119.
Respectfully, Mark D. Humphrey Sr. Manager Licensing Constellation Energy Generation, LLC Attachments:
- 1. Zion Nuclear Power Station Annual Radiological Environmental Operating Report
- Humphrey, Mark D.
Digitally signed by Humphrey, Mark D.
Date: 2024.05.15 08:58:33
-05'00'
ATTACHMENT 1 Zion Nuclear Power Station Annual Radiological Environmental Operating Report
Docket No:
50-295 50-304 72-1037 ZION NUCLEAR POWER STATION Annual Radiological Environmental Operating Report 1 January through 31 December 2023 Prepared By Zion Solutions, LLC Zion Nuclear Power Station Zion, IL 60099 May 2024
2 2023 Zion AREOR Table Of Contents I.
Summary and Conclusions................................................................................... 4 II.
Introduction........................................................................................................... 4 A.
Objectives of the REMP............................................................................. 5 B.
Implementation of the Objectives............................................................... 5 III.
Program Description............................................................................................. 5 A.
Sample Collection...................................................................................... 5 B.
Data Interpretation..................................................................................... 6 C.
Ambient Gamma Radiation........................................................................ 7 D.
Program Exceptions.................................................................................. 7 E.
Program Changes...................................................................................... 7 Appendices Appendix A Radiological Environmental Monitoring Report (REMP) Summary Tables Table A-1 Radiological Environmental Monitoring Annual Summary for the Zion Nuclear Power Station, 2023 Appendix B Location Designation, Distance & Direction, and Sample Collection &
Analytical Methods Tables Table B-1 Radiological Environmental Monitoring Program - Sampling Locations, Distance and Direction, Zion Nuclear Power Station, 2023 Figures Figure B-1 Inner and Outer Ring TLD Locations of the Zion Nuclear Power Station, 2023
3 2023 Zion AREOR Appendix C Tables Data Tables Table C-III.1 All TLD Results for All Locations Table C-III.2 Mean Quarterly TLD Results for Inner Ring, Outer Ring, and Control Stations for Zion Nuclear Power Station, 2023 Table C-III.3 Figures Summary of the Ambient Dosimetry Program for Zion Nuclear Power Station, 2023 Figure C-7 TLD Historical Dose Trending
4 2023 Zion AREOR I.
Summary and Conclusions This report on the Radiological Environmental Monitoring Program (REMP) conducted for the Zion Nuclear Power Station (ZNPS) by ZionSolutions (ZS) covers the period 1 January 2023 through 31 December 2023. Zion Station started decommissioning in 2010, and that effort is now complete with the NRC termination of Zions Operation/Decommissioning License at the end of August 2023. This final AREOR report is required up to the ZNPS license termination in the 4th quarter of 2023. For simplicity, accessibility and consistency, the last quarter of 2023 data is reported here in accordance with Part 50 report format as outlined in NUREG-1301, Offsite Dose Calculation Manual Guidance: Standard Radiological Effluent Controls for Pressurized Water Reactors. The termination of the ZNPS license(s) results in a reduction of the licensed facilitys footprint encompassing the Independent Spent Fuel Storage Installation (ISFSI) for continued site storage of the Spent Nuclear Fuel and Greater Than Class C Waste (GTCC) in sealed and shielded canisters until the national repository is ready to receive these.
In 2023, 600 analyses were performed on 200 samples. Environmental gamma radiation measurements were performed quarterly using thermoluminescent dosimeters (TLDs).
These samples include a full year of direct dose TLD monitor results. In assessing all the data gathered for this report and comparing these results with pre-operational data, it was concluded that the decommissioning of ZNPS had no adverse radiological impact on the environment or the general public.
II.
Introduction The Zion Nuclear Power Station (ZNPS) consisted of two 1,100 MWt pressurized water reactors, was owned and operated by Exelon Corporation, and is located in Zion, Illinois adjacent to Lake Michigan. The site is located on the western shore of Lake Michigan, approximately 50 miles north of Chicago, Illinois. Unit No. 1 went critical in December 1973. Unit No. 2 went critical in September 1974.
The plant permanently ceased operation in January of 1998 and has been permanently defueled, and, except for the Independent Spent Fuel Storage Installation (ISFSI), no above-ground structures remain on site. All structures were surveyed, characterized, demolished, and shipped off site as waste, including some structural material discovered in 2022 and structural demolition remnants consisting of wood, metal, concrete fragments, and concrete retained until license termination in the event the regulator requested additional analyses.
Some clean construction debris was used as backfill in accordance with the License Termination Plan (LTP). The only known sources of radioactive material on site include spent fuel and GTCC waste stored in canisters on the Independent Spent Fuel Storage Installation (ISFSI) and trace amounts of radioactive material in backfilled structures and surface soil per the Stations LTP.
5 2023 Zion AREOR This report documents the results of those analyses performed by Mirion Technologies on samples collected during the period 1 January 2023 through 31 December 2023 in accordance with the Zion Station Off Site Dose Calculation Manual (ODCM) Revision 12 issued in January 2020.
A.
Objectives of the REMP The objectives of the REMP are to:
- 1. Provide data on measurable levels of radiation and radioactive materials at and beyond the site boundary, in public areas and in the environment.
- 2. Evaluate the relationship between quantities of radioactive material released from the plant and resultant radiation doses to individuals from principal pathways of exposure.
B.
Implementation of the Objectives The implementation of the objectives is accomplished by:
- 1. Identifying significant exposure pathways.
- 2. Establishing baseline radiological data of media within those pathways.
- 3. Continuously monitoring those media before, during and after Station operation to assess Station radiological impacts (if any) on man and the environment.
III.
Program Description A.
Sample Collection (Performed between January 1 and 31 December 2023)
Samples for the ZNPS REMP were collected by Zion Solution Contractors.
Ambient Gamma Radiation Direct radiation measurements were made with Panasonic Environmental TLD type 814 with 3 CaSO4 elements. Each location consisted of two TLD sets. The TLD locations were placed on, around, and surrounding the ZNPS site at the following locations in 2023, as specified by the requirements of revision 12 to the ODCM:
- 1.
Inner Ring: Z-101, Z-103, Z-106, Z-108, Z-109, Z-110, Z-111, Z-112, Z-121, Z-124, Z-125, Z-129, Z-130, Z-131, Z-150, Z-151, Z-152, Z-153, Z154, Z-155 Outer Ring: Z-113, Z-114, Control: Z-13
6 2023 Zion AREOR The specific TLD locations were determined by the following criteria:
- 1. The presence of relatively dense population.
- 2. Site meteorological data, taking into account distance and elevation for each of the sixteen 221/2 degree sectors around the site, where estimated annual dose from ZNPS, if any, would be most significant.
- 3. On hills free from local obstructions and within clear line of sight to construction activities (where practical) and the ISFSI.
(Two TLDseach comprised of three CaSO4 elements enclosed in plasticwere placed at each location approximately four to eight feet above ground level. The TLDs were exchanged quarterly and sent to Mirion Technologies for analysis.)
- 4. Ambient gamma radiation levels at various locations on and off site up to 10 miles away (control) using multi-chip thermioluminescent dosimeters (TLDs).
B.
Data Interpretation The radiological and direct radiation data collected prior to Zion Nuclear Power Station becoming operational were used as a baseline with which these operational data were compared. For the purpose of this report, Zion Nuclear Power Station was considered operational at initial criticality.
In addition, data was compared to previous years' operational data for consistency and trending. Several factors were important in the interpretation of the data:
- 1. Lower Limit of Detection and Minimum Detectable Concentration The lower limit of detection (LLD) is defined as the smallest concentration of radioactive material in a sample that would yield a net count (above background) that would be detected with only a 5%
probability of falsely concluding that a blank observation represents a real signal. The LLD is intended as a before the fact estimate of a system (including instrumentation, procedure, and sample type) and not as an after-the-fact criteria for the presence of activity. All analyses were designed to achieve the required ZNPS detection capabilities for environmental sample analysis.
The minimum detectable concentration (MDC) is defined above with the exception that the measurement is an after the fact estimate of the presence of activity.
7 2023 Zion AREOR C.
Ambient Gamma Radiation Ambient gamma radiation levels were measured utilizing Panasonic Environmental Type 814 CaSO4 thermoluminescent dosimeters (TLDs).
Fifty TLDs were mounted at 23 locations around the site. Results of TLD measurements are listed in Tables C-III.1 to C-III.3, Appendix C.
Most TLD measurements were below 25 mR/quarter, with a range of 13 mR/quarter to 31 mR/quarter. As there are duplicate TLDs posted at each location, the highest value is in Appendix C for each location except where minimums are reported. When direct dose in 2023 is compared to direct dose the previous seven years (2016-2023) at the four compass points surrounding decommissioning activities within the site boundary, there is a visible drop in direct dose. This is attributed to a steady reduction in source term over the same period, including shipment off site of demolition materials inside the former protected area and shipment by rail and truck of the debris to Energy Solutions low level waste facilities in Utah.
When looking at a more specific historical set of TLDs, those most likely to be impacted by direct radiation from the Independent Spent Fuel Storage Installation (ISFSI) by close proximity and line of site positioning inside the site boundary (Figure C-7), a significant increase in direct dose initially is evident in 2015 following completion of the transfer of spent fuel to the ISFSI. After 2015, a drop in direct dose is evident due in part to site source term reduction, and to a lesser extent, decay of the spent fuel and GTCC waste (Co-60). Cobalt 60, present in high dose stellate components, has a 5-year half-life which means that cobalt will have gone through two half-lives by 2025. At that point, it will be approaching 25% of its original activity levels present when it was sealed its GTCC canister. With the 2020 ISFSI site only revision to the ODCM (Rev 12) the changes in TLD placement precluded the ability to continue this dose reduction monitoring.
D.
Program Exceptions There were no program exceptions or errata data identified in the 2023 AREOR program. The program exceptions identified in the 2023 ARERR neutron Type 36 TLD results from Mirion are addressed in that report.
E.
Program Changes There were no changes to the program in 2023. Revision 12 to the ODCM is the revision currently in effect.
8 2023 Zion AREOR APPENDIX A RADIOLOGICAL ENVIRONMENTAL MONITORING REPORT
SUMMARY
9 2023 Zion AREOR APPENDIX B LOCATION DESIGNATION, DISTANCE & DIRECTION, AND SAMPLE COLLECTION & ANALYTICAL METHODS
10 2023 Zion AREOR TABLE B-1:
Radiological Environmental Monitoring Program - Sampling Locations, Distance and Direction, Zion Nuclear Power Station, 2023 Location Location Description Distance & Direction From Site A. Environmental Dosimetry - TLD Inner Ring Z-101-1 and -2 0.40 miles NNE Z-103-1 and -2 0.39 miles NE Z-106-1 and -2 0.31 miles ENE Z-108-1 and -2 0.24 miles E Z-109-1 and -2 0.22 miles E Z-110-1 and -2 0.11 miles SE Z-111-1 and -2 0.11 miles SSW Z-112-1 and -2 0.50 miles W Z-121-1 and -2 0.31 miles NNE Z-124-1 and -2 0.16 miles SSW Z-125-1 and -2 0.15 miles SSE Z-129-1 and -2 0.29 miles N Z-130-1 and -2 0.12 miles NNW Z-131-1 and -2 0.07 miles NW Z-150-1 and -2 0.08 miles WNW Z-151-1 and -2 0.08 miles W Z-152-1 and -2 0.09 miles WSW Z-153-1 and -2 0.11 miles SW Z-154-1 and -2 0.09 miles S Z-155-1 and -2 0.10 miles SSE Outer Ring Z-113-1 and -2 0.53 miles WNW Z-114-1 and -2 0.56 miles NW Control Z-13-1 thru -6 13.0 miles NW TLD Thermoluminescent Dosimetry Quarterly TLDs comprised of two Panasonic Environmental TLD type 814 with 3 CaSO4 elements in each dosimeter at each location.
Mirion Technologies
11 2023 Zion AREOR FIGURE B-1: Inner and Outer Ring TLD Locations of the Zion Nuclear Power Station, 2023
12 2023 Zion AREOR APPENDIX C DATA TABLES
13 2023 Zion AREOR Table C-lll.1 All TLD RESULTS FOR ALL LOCATIONS
14 2023 Zion AREOR Table C-III.2 MEAN QUARTERLY TLD RESULTS FOR INNER RING, OUTER RING, AND CONTROL STATIONS FOR ZION NUCLEAR POWER STATION, 2023 Results in Units of Milli-Roentgen/Quarter
+/- 2 Standard Deviations of the Station Data (All TLD results)
COLLECTION PERIOD INNER RING OUTER RING CONTROL.
JAN-MAR 17 +/- 6 15 +/- 0 17 +/- 0 APR-JUN 18 +/- 6 16 +/- 3 19 +/- 1 JUL-SEP 19 +/- 6 18 +/- 2 19 +/- 1 OCT-DEC 21 +/- 6 19 +/- 1 20 +/- 1 Table C-III.3
SUMMARY
OF THE AMBIENT DOSIMETRY PROGRAM FOR ZION NUCLEAR POWER STATION, 2023 DOSE RESULTS IN UNITS OF MILLI-ROENTGEN /QUARTER SAMPLES PERIOD PERIOD PERIOD MEAN LOCATION ANALYZED MINIMUM MAXIMUM
+/- 2 S.D.
INNER RING OUTER RING CONTROL 160 16 24 13 14 16 31 20 21 19 +/- 6 17 +/- 2 19 +/- 2 INNER RING STATIONS - Z-101, Z-103, Z-106, Z-108, Z-109, Z110, Z-111, Z-112, Z-121, Z-124, Z-125, Z-129, Z130, Z-131, Z-150, Z-151, Z-152, Z-153, Z-154, Z-155 OUTER RING STATIONS - Z-113, Z-114 CONTROL STATION - Z-13
15 2023 Zion AREOR FIGURE C-7: TLD Historical Dose Trending Historical TLD Trend Graph Showing Decrease in Dose After Spent Fuel Placed on Pad with Some Radioactive Material Decay and Removal from Site of Demolition Material.
- Cannot Maintain this Trending beyond 2020 with the Removal and Repositioning of TLDs as an ISFSI only Site, however the bar graph is still useful for depicting the activity level drop with radioactive decay of Co60 over time.
A Condition Report was issued in 2023 to document erroneously high neutron results in the 2nd quarter due to the application of incorrect dose conversion factors being applied to type 36 TLD results (operating plant vs decommissioning plant dose conversion factors were applied to spent fuel in ISFSI canisters reported by Mirion).
Mirion issued an internal CR and agreed to forward a copy of the closure report to Constellation to permit tracking and documentation of corrective actions taken to close out the CR.
0.00 10.00 20.00 30.00 40.00 50.00 60.00 2015 2016 2017 2018 2019 2020 2015 - 2020*
Z Control Z-01*
Z-109 Z-131
ATTACHMENT 2 Zion ISFSI Annual Radiological Environmental Operating Report
Zion 2023 AREOR Page 1 of 18 SRRS 2C.111 Zion ISFSI Annual Radiological Environmental Operating Report Facility Operating License: DPR-39 and DPR-48 NRC Docket: 50-295, 50-304, and 72-1037 Period: 11/17/23 to 12/31/23
Zion 2023 AREOR Page 2 of 18 SRRS 2C.111 Table of Contents I.
Summary and Conclusions..............................................................................................4 II.
Introduction......................................................................................................................5 A.
Objectives of the REMP........................................................................................5 B.
Implementation of the Objectives..........................................................................5 III.
Program Description........................................................................................................6 A.
Sample Collection.................................................................................................6 B.
Sample Analysis....................................................................................................6 C.
Data Interpretation................................................................................................7 D.
Program Exceptions..............................................................................................7 E.
Program Changes.................................................................................................7 IV.
Results and Discussion....................................................................................................8 A.
Ambient Gamma Radiation...................................................................................8 B.
Deleted C.
Deleted D.
Errata Data..................................................................................................... None Appendices Appendix A Radiological Environmental Monitoring Report (REMP) Summary Table A-1 Radiological Environmental Monitoring Program Annual Summary for the Zion ISFSI, 2023 Appendix B Location Designation, Distance & Direction, and Sample Collection & Analytical Methods Table B-1 Radiological Environmental Monitoring Program - Sampling Locations, Distance and Direction, Zion ISFSI, 2023 Table B-2 Radiological Environmental Monitoring Program - Summary of Sample Collection and Analytical Methods, Zion ISFSI, 2023 Figure B-1 Inner and Outer Ring OSLD Locations of the Zion ISFSI, 2023
Zion 2023 AREOR Page 3 of 18 SRRS 2C.111 Appendix C Table C-III.1 Quarterly OSLD Results for Zion ISFSI, 2023 Table C-III.2 Mean Quarterly OSLD Results for the ISFSI Inner Ring, Outer Ring, And Control Locations for Zion Nuclear Power Station, 2023 Table C-III.3 Summary of the Ambient Dosimetry Program for Zion ISFSI, 2023 Figure C-7.1 OSLD Historical Dose Trending Figure C-7.2 Owner Controlled Boundary Appendix D Errata Data Intentionally Blank as there is no data for the 2023 period for Constellation
Zion 2023 AREOR Page 4 of 18 SRRS 2C.111 I.
Summary and Conclusions The License for Zion ISFSI was transferred to Constellation on 11/16/23 with Constellation monitoring beginning on 11/17/23. Environmental dosimetry deployed by Constellation personnel at the beginning of the fourth quarter to ensure a full monitoring period. Additionally, a parallel monitoring program was started approximately two years prior to establish a baseline monitoring value. While the fourth quarter was the first quarter for operation by Constellation, this report will contain dosimeter responses for the entire year and trending data prior to 2023.
ZionSolutions also provided monitoring for each quarter in 2023 and will submit a report for monitoring and work performed by their personnel. There is an overlap in monitoring provided in 2023 by ZionSolutions and Constellation.
In 2023, 350 analyses were performed on 88 samples (locations). One of the dosimeters at location Z-101 appeared to be lost due to high-wind conditions from the lake. Dosimeters at that location were subsequently put into a cage to prevent their loss in future high-wind conditions. Each location has two dosimeters and each dosimeter contains two dose elements and comprising two analyses otherwise the number of analyses for 88 locations would have been 352. These samples include a full year of direct dose OSLD monitor results. In assessing all the data gathered for this report and comparing these results with historical data, it was concluded that the Zion ISFSI operation had no adverse radiological impact on the environment.
Environmental gamma radiation measurements were performed quarterly using Landauer gamma sensitive Optically Stimulated Luminescence dosimetry (OSLD).
Zion 2023 AREOR Page 5 of 18 SRRS 2C.111 II.
Introduction The Zion Nuclear Power Station (ZNPS), now Zion ISFSI-only facility, consisted of two 1,100 MWt pressurized water reactors. It was owned and operated by Exelon Corporation, and is located in Zion, Illinois adjacent to Lake Michigan. The site is located on the western shore of Lake Michigan, approximately 50 miles north of Chicago, Illinois. Unit No. 1 went critical in December 1973. Unit No. 2 went critical in September 1974. The plant permanently ceased operation in January of 1998 and has been permanently defueled, and except for the Independent Spent Fuel Storage Installation (ISFSI), no above-ground structures remain on site. All structures were surveyed, characterized, demolished, and shipped off site as waste.
The only known sources of radioactive material on site include spent fuel and GTCC waste stored in canisters on the Independent Spent Fuel Storage Installation (ISFSI). This report covers those analyses performed by Landauer Inc on samples collected during the period 1 January 2023 through 31 December 2023.
A.
Objectives of the REMP The objectives of the REMP are to:
1.
Provide data on measurable levels of radiation and radioactive materials at and beyond the site boundary, in public areas and in the environment.
2.
Evaluate the relationship between quantities of radioactive material released from the plant and resultant radiation doses to individuals from principal pathways of exposure.
B.
Implementation of the Objectives The implementation of the Objectives is accomplished by:
1.
Identifying significant exposure pathways 2.
Establishing baseline radiological data of media within those pathways 3.
Continuously monitoring those media before, during and after Station operation to assess Station radiological impacts (if any) on man and the environment.
Zion 2023 AREOR Page 6 of 18 SRRS 2C.111 III.
Program Description A.
Sample Collection (Performed between January 1 and December 2023)
Samples for the facility were collected by Constellation personnel. The sampling methods used are listed in Table B-2.
Ambient Gamma Radiation Direct radiation measurements were made with Landauer environmental OSLD dosimeters with two gamma sensitive elements in each dosimeter. One dosimeter provides two measurements. Two dosimeters were placed at each location which yields four independent results. The OSL dosimeters were placed at field and control locations as specified by revision 12 of the ODCM.
B.
Sample Analysis Sample analysis is performed by Landauer personnel once received from Constellation personnel. The amount of radiation exposure is measured by stimulating the dosimeter material with green light from a light emitting diode (LED). The resulting blue light emitted after stimulation indicates the level of radiation exposure. Constellation uses the V03NH dosimeters type with enhanced analytical sensitivity and a minimum detectable dose of 0.1 mrem. The enhanced analysis is a result of implementing a second read period at the end of the normal period where glow-curve data is collected to get the tailing as the glow curve subsides. The improved technique is collecting more area under the curve for dose response compared to normal monitoring and sensitivity of 5 mrem.
Inner Ring: Z-101, Z-103, Z-106, Z-108, Z-109, Z-110, Z-111, Z-112, Z-121, Z-124, Z-125, Z-129, Z-130, Z-131, Z-150, Z-151, Z-152, Z-153, Z154, Z-155 Outer Ring: Z-113, Z-114, Control: Z-13 The dosimeter locations were determined by the following criteria:
1.
The presence of relatively dense population.
2.
Site meteorological data taking into account distance and elevation for each of the sixteen-22 1/2-degree sectors around the site, where estimated annual dose from the facility, if any, would be most significant.
3.
On hills free from local obstructions and within clear line of sight to the ISFSI.
Each location is approximately four to eight feet above ground level.
4.
Ambient gamma radiation levels at various locations on and off site up to 10 miles away (control) using multi-chip OSL dosimeters
Zion 2023 AREOR Page 7 of 18 SRRS 2C.111 C.
Data Interpretation The start of monitoring by Constellation began 11/17/23 with the transfer of the license from Zion Solutions. Dosimeters were already deployed at the beginning of the quarter to permit a proper period and sensitivity of analysis.
Lower Limit of Detection The lower limit of detection (LLD) is defined as the smallest concentration of radioactive material in a sample that would yield a net count (above background) that would be detected with only a 5% probability of falsely concluding that a blank observation represents a "real" signal. There is no required LLD and no control subtraction is performed so there is always a positive dosimeter value. The minimum detectable dose on the environmental dosimeter is 0.1 mrem.
D.
Program Exceptions One of the dosimeters at location Z-101 appeared to be lost due to high-wind conditions from the lake. Dosimeters at that location were subsequently put into a cage to prevent their loss in future high-wind conditions.
E.
Program Changes Constellation became the licensee for monitoring starting 11/17/23 and deployed a parallel set of dosimetry with Zion Solutions for 2023
Zion 2023 AREOR Page 8 of 18 SRRS 2C.111 IV.
Results and Discussion A.
Ambient Gamma Radiation Ambient gamma radiation levels were measured with Landauer OSL environmental dosimeters. Forty-four dosimeters were mounted at 22 locations around the facility with six control dosimeters at one location approximately 10 miles NW of the facility. Results of dosimeter measurements are listed in Tables C-III.1 to C-III.3 B.
Deleted C.
Deleted D.
Errata Data There was no errata data for the 2023 time period for Constellation operation from 11/17/23 to 12/31/23.
Zion 2023 AREOR Page 9 of 18 SRRS 2C.111 Appendix A Radiological Environmental Monitoring Report (REMP) Summary
Zion 2023 AREOR Page 10 of 18 SRRS 2C.111 Table A-1 Radiological Environmental Monitoring Program Annual Summary for the Zion ISFSI, 2023 Name of Facility: Zion ISFSI Location of Facility: Zion, Il Docket Number: 50-295, 50-304, 72-1037 Reporting Period: 2023 Medium or Pathway Sampled (Unit of Measurement)
Types of Analysis Performed Number of Analyses Performed Required Lower Limit of Detection (LLD)
Indicator Locations Mean (f)
Range Control Location Mean (f)
Range Location with the Highest Annual Mean Number of Non-Routine Reported Measurements Mean (f)
Range Location Name Direct Radiation (milli-Roentgen/Qtr)
OSLD Quarterly 350 N/A 18.3 (88/88) 13-30 20.7 (24/24) 17-25 26.5 (4/4) 23-30 Z-131 0.07 mi NW 0
(M) The mean values are calculated using the positive values. (F) Fraction of detectable measurements are indicated in parenthesis
Zion 2023 AREOR Page 11 of 18 SRRS 2C.111 Appendix B Location Designation, Distance and Direction, and Sample Collection and Analytical Methods
Zion 2023 AREOR Page 12 of 18 SRRS 2C.111 Table B-1 Radiological Environmental Monitoring Program - Sampling Locations, Distance and Direction, Zion ISFSI, 2023 Location Type Location Distance and Direction from Site A. Environmental Dosimetry - OSL Control Loc Z-013 CONTROL-1 13.00 mi NW 21.50 km (Q)
Z-013 CONTROL-2 13.00 mi NW 21.50 km (Q)
Z-013 CONTROL-3 13.00 mi NW 21.50 km (Q)
Z-013 CONTROL-4 13.00 mi NW 21.50 km (Q)
Z-013 CONTROL-5 13.00 mi NW 21.50 km (Q)
Z-013 CONTROL-6 13.00 mi NW 21.50 km (Q)
Inner Ring Z-101 0.40 mi NNE 0.65 km (B)
Z-103 0.39 mi NE 0.62 km (C)
Z-106 0.31 mi ENE 0.45 km (D)
Z-108 0.24 mi E 0.38 km (E)
Z-109 0.22 mi ESE 0.35 km (F)
Z-110 0.11 mi SE 0.18 km (G)
Z-111 0.11 mi SSW 0.17 km (K)
Z-112 0.50 mi W 0.81 km (N)
Z-121 0.31 mi NNE 0.51 km (B)
Z-124 0.16 mi SSW 0.26 km (K)
Z-125 0.15 mi SSE 0.24 km (J)
Z-129 0.29 mi N 0.47 km (A)
Z-130 0.12 mi NNW 0.20 km (R)
Z-131 0.07 mi NW 0.11 km (Q)
Z-150 0.08 mi WNW 0.13 km (P)
Z-151 0.08 mi W 0.12 km (N)
Z-152 0.09 mi WSW 0.15 km (M)
Z-153 0.11 mi SW 0.18 km (L)
Z-154 0.09 mi S 0.15 km (J)
Z-155 0.10 mi SSE 0.16 km (H)
Outer Ring Z-113 0.53 mi WNW 0.85 km (P)
Z-114 0.56 mi NW 0.90 km (Q)
Table B-2 Radiological Environmental Monitoring Program - Summary of Sample Collection and Analytical Methods, Zion ISFSI, 2023 Sample Medium Analysis Sampling Method Analytical Procedure Number OSL Dosimeter Optically Stimulated Luminescence Dosimetry (OSL)
Quarterly dosimeters.
There are two dosimeters at each location and each dosimeter has two gamma sensitive elements for a total of four measurements at each location Landauer Inc
Zion 2023 AREOR Page 13 of 18 SRRS 2C.111 Figure B-1 Inner and Outer OSLD Ring Locations The following figure is from the Offsite Dose Calculation Manual (ODCM).
Zion 2023 AREOR Page 14 of 18 SRRS 2C.111 Appendix C Data Tables
Zion 2023 AREOR Page 15 of 18 SRRS 2C.111 Table C-III.1 Quarterly OSLD Results for Zion ISFSI, 2023 Results in units of milli-Roentgen/Qtr +/- 2 Standard Deviations Station Code Mean +/- 2 SD Jan - Mar Apr - Jun Jul - Sep Oct - Dec Control Location Z-013 CONTROL-1 20.75 +/- 5.26 17 22 21 23 Z-013 CONTROL-2 21.25 +/- 5.51 18 24 20 23 Z-013 CONTROL-3 20.25 +/- 4.12 18 22 19 22 Z-013 CONTROL-4 20.25 +/- 5.74 17 20 20 24 Z-013 CONTROL-5 20.75 +/- 7.00 19 22 17 25 Z-013 CONTROL-6 20.75 +/- 5.97 17 22 20 24 Inner Ring Z-101 15.75 +/- 5.74 14 15 14 20 Z-103 17.25 +/- 5.74 15 18 15 21 Z-106 16.25 +/- 4.43 15 17 14 19 Z-108 17.25 +/- 5.26 16 17 15 21 Z-109 17.25 +/- 5.74 15 18 15 21 Z-110 18.75 +/- 5.51 17 20 16 22 Z-111 18.75 +/- 5.51 16 20 17 22 Z-112 18.75 +/- 4.43 16 18 21 20 Z-121 15.50 +/- 3.83 14 16 14 18 Z-124 16.75 +/- 5.51 14 18 15 20 Z-125 17.75 +/- 5.97 14 17 21 19 Z-129 15.25 +/- 5.74 13 16 13 19 Z-130 17.00 +/- 6.32 15 18 14 21 Z-131 26.50 +/- 7.02 23 29 24 30 Z-150 21.25 +/- 7.55 18 24 18 25 Z-151 22.75 +/- 5.51 21 24 20 26 Z-152 19.50 +/- 5.29 18 20 17 23 Z-153 18.25 +/- 5.26 16 18 17 22 Z-154 19.50 +/- 4.16 17 20 19 22 Z-155 19.75 +/- 4.73 18 20 18 23 Outer Ring Z-113 16.00 +/- 4.90 14 17 14 19 Z-114 16.75 +/- 4.43 14 18 16 19
Zion 2023 AREOR Page 16 of 18 SRRS 2C.111 Table C-III.2 Mean Quarterly OSLD Results for the ISFSI Inner Ring, Outer Ring, And Control Locations for Zion Nuclear Power Station, 2023 Results in units of milli-Roentgen/Qtr
+/-2 Standard Deviations of the Station Data (All OSLD Results)
Collection Period Control Inner Ring Outer Ring Jan - Mar 17.67 +/- 1.63 16.25 +/- 4.94 14.00 +/- 0.00 Apr - Jun 22.00 +/- 2.53 19.15 +/- 6.59 17.50 +/- 1.41 Jul - Sep 19.50 +/- 2.76 16.85 +/- 5.89 15.00 +/- 2.83 Oct - Dec 23.50 +/- 2.10 21.70 +/- 5.59 19.00 +/- 0.00 Table C-III.3 Summary of the Ambient Dosimetry Program for Zion ISFSI, 2023 Results in units of milli-Roentgen/Qtr Location Samples Analyzed Period Minimum Period Maximum Period Mean
+/- 2 S.D.
Control Loc 24 14 25 18.71 +/- 4.86 Inner Ring 80 12 30 17.47 6.93 Outer Ring 8
12 19 15.23 4.04 Inner Ring - Z-101, Z-103, Z-106, Z-108, Z-109, Z110, Z-111, Z-112, Z-121, Z-124, Z-125, Z-129, Z130, Z-131, Z-150, Z-151, Z-152, Z-153, Z-154, Z-155 Outer Ring - Z-113, Z-114 Control Location - Z-013
Zion 2023 AREOR Page 17 of 18 SRRS 2C.111 Figure C-7.1 OSLD Historical Dose Trending (milli-Roentgen)
Monitoring Location 10/1/2020 1/1/2021 4/1/2021 7/1/2021 10/1/2021 7/1/2022 10/1/2022 1/1/2023 4/1/2023 7/1/2023 10/1/2023 1/1/2024 Z-013 CONTROL-1 19 18 15 19 18 17 19 17 22 21 23 18 Z-013 CONTROL-2 17 18 16 20 17 17 19 18 24 20 23 17 Z-013 CONTROL-3 18 17 16 20 18 18 20 18 22 19 22 17 Z-013 CONTROL-4 17 17 14 20 18 16 20 17 20 20 24 18 Z-013 CONTROL-5 17 17 16 19 17 18 17 19 22 17 25 17 Z-013 CONTROL-6 18 16 15 20 16 17 18 17 22 20 24 17 Z-101 14 16 13 14 13 13 15 14 15 14 20 13 Z-103 15 17 14 16 14 14 16 15 18 15 21 14 Z-106 17 17 14 15 14 13 15 15 17 14 19 14 Z-108 17 17 15 16 15 14 16 16 17 15 21 15 Z-109 18 18 16 17 15 14 16 15 18 15 21 14 Z-110 18 21 17 18 15 15 17 17 20 16 22 16 Z-111 17 20 17 18 16 16 19 16 20 17 22 17 Z-112 17 18 15 15 15 13 15 16 18 21 20 14 Z-113 16 17 14 13 12 12 15 14 17 14 19 13 Z-114 16 17 14 14 14 14 16 14 18 16 19 14 Z-121 14 16 13 15 12 12 15 14 16 14 18 13 Z-124 16 17 14 14 13 12 15 14 18 15 20 14 Z-125 15 17 14 15 14 12 14 14 17 21 19 13 Z-129 15 16 12 15 14 13 15 13 16 13 19 13 Z-130 17 19 Lost 16 14 13 15 15 18 14 21 14 Z-131 27 30 26 26 24 21 25 23 29 24 30 25 Z-150 22 23 20 20 20 18 20 18 24 18 25 20 Z-151 23 24 20 21 21 19 21 21 24 20 26 20 Z-152 19 21 18 20 16 16 19 18 20 17 23 17 Z-153 18 19 15 17 15 14 20 16 18 17 22 15 Z-154 18 21 16 18 17 15 18 17 20 19 22 17 Z-155 19 21 17 20 18 16 18 18 20 18 23 17 Constellation personnel began monitoring in the fourth quarter of 2023. Multiple prior quarters were collected as part of a parallel test program to establish a baseline prior to assuming operations. The value for 2023 appears to be 1 or 2 mR higher than previous quarters and came back down 2024 Q1. Most likely due to low-level irradiation in transit.
Zion 2023 AREOR Page 18 of 18 SRRS 2C.111 Figure C-7.2 Owner Controlled Boundary