ML18215A226
| ML18215A226 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 06/25/2018 |
| From: | Brehm D M Omaha Public Power District |
| To: | Office of Nuclear Material Safety and Safeguards |
| References | |
| LIC-18-0023 FC-18-010, Rev 1 | |
| Download: ML18215A226 (12) | |
Text
UHHU OnabaPoUk Power IXsHkt Page 1 of 12 FC-18-010 Revision 1 Partial Site Release Radiological Measurements Prepared By: DM Brehm Reviewed By: AK Barker Approved By: Date lolzsjlt Date Date Partial Site Release Radiological Measurements FC-18-010 OaahaPublkPowerOisMel ReVislOP 1 Page 2 of 12
1.0 INTRODUCTION
The purpose of this document is to compile the results of the field measurements performed in support of the partial site release of Fort Calhoun Station property outside of the Protected Area. The measurements performed include discrete soil samples, scanning surveys for gross gamma radiation, and in-situ gamma spectroscopy.
2.0 BACKGROUND
The objective of the surveys and sampling performed is to perform a radiological characterization of the open land areas classified as "non-impacted" by the limited Historical Site Assessment (HAS) in order to establish the empirical basis for that classification.
It is intended that this survey will meet the minimum requirements of the guidance contained in NUREG-1575, "Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM)." The surveys were performed as directed by FC-18-007 Rev. 0, "SURVEY PLAN - Non-Impacted Open Land Survey Units." 3.0 DEFINITIONS
3.1 ISOCS
- In-Situ Object Counting System. ISOCS is a proprietary (Mirion/Canberra) gamma spectroscopy calibration methodology that determines the efficiency curve based on a detailed mathematical model.4.0 IVIETHODOLOGY
4.1 Direct
Gamma Scans The direct gamma scans were performed using Ludlum 44-10 2-in x 2-in Nal probes connected to a Ludlum 4404-4 multi-channel analyzer that was in turn connected to a hand-held computer for data logging. Data points were recorded, along with the associated GPS coordinates, at one-second intervals.
The scan distances and speeds were in accordance with FC-18-006 Rev. 0, "Soil Minimum Detectable Concentrations for 2x2 Nal Probes." The resulting data {< 30,000 points) was analyzed for outliers or significant deviations from the mean for each survey location.
Any locations that showed as greater than the calculated action level (MDCR + Average Background) where one of the adjacent points was also greater than MDA were re-surveyed.
Background data was obtained at several locations determined to be similar in both land-use and geology. Three distinct types were identified:
field (plowed earth actively farmed), treed, and sand. Action Levels were calculated for each area type and applied as appropriate to each survey location.
See Attachment
- 5.
umu Partial Site Release Radiological Measurements FC-18-010 OaSa^k^wetO^
ReViSlOH 1 Page 3 of 12 4.2 Direct Gamma Spectroscopy Measurements The direct gamma spectroscopy measurements were performed with a Canberra ISOGS characterized BEGe detector at the center of each survey unit based on FC-18-008 Rev 0, "Use of In-Situ Gamma Spectroscopy for Characterization." The geometry & 20-minute count time resulted in a Cs-137 MDA of approximately 0.2 pCi/g.The efficiency calibration for the measurements was determined using the Canberra ISOCS software.
The soil density used was 1.33 g/cm^ as specified in U.S. Dept. of Agriculture literature.
4.3 Discrete
Soil Samples The discrete soil samples were obtained from each survey unit at an elevated count rate from the Nal scans or the center of the area If no elevated count rates were identified.
The samples were counted on an HPGe detector and analyzed using the Apex Gamma system. The count time & geometry was arranged so that the Cs-137 minimum detectable activity (MDA) was < 0.05 pCi/g.The soil was dried at 105°C until no moisture was noted.The efficiency calibration was determined using the Canberra LABSOCS software & the measured volume and mass of the samples. A specific calibration was determined for each soil density rounded to the nearest 0.1 g/cm^.
5.0 CONCLUSION
S Based on the data obtained it can be concluded that a non-impacted classification for these areas is appropriate as all measurements were less than the established background values (less than the mean plus 2a).5.1 Direct Gamma Scans The direct gamma scans using Nal detectors did not identify any locations that required further survey or examination.
All areas surveyed showed count rates consistent with the expected background count rates.5.2 Direct Gamma Spectroscopy Measurements The direct gamma spectroscopy measurements did not identify any FCS related radioactivity.
They did identify low-levels of Cs-137 in low-points and relatively undisturbed locations (e.g., wooded areas) consistent with the expected residual levels from historical nuclear weapons testing and all were less than the arithmetic mean plus two-sigma (95% confidence interval) of the background samples that identified Cs-137.See FC-18-003, "Evaluation of Cs-137 Global Fallout in Soils at Fort Calhoun Station." 5.3 Discrete Soil Samples The discrete soil samples analyzed by gamma spectroscopy measurements did not identify any FCS related radioactivity.
They did identify low-levels of Cs-137 in low-UfVfU Partial Site Release Radiological Measurements FC-18-010 OmthiPutHePimrDtiOist RevlslOn 1 Page 4 of 12 points and relatively undisturbed locations (e.g. wooded areas) consistent with the expected residual levels from historical nuclear weapons testing and ail were less than the arithmetic mean plus two-sigma (95% confidence interval) of the background samples that identified Cs-137. See FC-18-003, "Evaluation of Cs-137 Global Fallout in Soils at Fort Calhoun Station." 6.0 ATTACHIVIENTS
6.1 Attachment
1 - Field Measurement Equipment Description
6.2 Attachment
2 - In-Situ Gamma Spectroscopy Data 6.3 Attachment 3 - Discrete Soil Sample Spectroscopy Data 6.4 Attachment 4 - Gross Gamma Radiation Scan Data Summary 6.5 Attachment 5 - Gross Gamma Radiation Scan Background Calculations
7.0 REFERENCES
7.1 FC-18-003, "Evaluation of Cs-137 Global Fallout in Soils at Fort Calhoun Station" 7.2 FC-18-006 Rev. 0, "Soil Minimum Detectable Concentrations for 2x2 Nal Probes" 7.3 FC-18-007 Rev. 0, "SURVEY PLAN - Non-Impacted Open Land Survey Units" 7.4 FC-18-009 Rev 0, "Use of In-Situ Gamma Spectroscopy for Characterization" umu Partial Site Release Radiological Measurements DnabtPntlk Power Disirkt FC-18-010 Revision 1 Page 5 of 12 Attachment 1 - Field Measurement Equipment Description
- 1. Nal Gamma Instrument The gross gamma scans were performed utilizing a Ludlum 4404-4 data logger with a 44-10 2x2 Nal detector.
The raw count and location data was recorded on a Trimble Geo7.s 2. ISOCS HPGe System The PCS HPGe ISOCS systems consists of an approximately 50% relative efficiency BEGe detector controlled by an Inspector 2000 multi-channel analyzer and operated via the Genie 2000 software.
The spectrum data was imported into the Apex Gamma software for final analysis and reporting.
The efficiency caiibrations used were determined using the Geometry Composer and ISOCS software.
umu Partial Site Release Radiological Measurements OmaAs Mile Power Kstritt FC-18-010 Revision 1 Page 6 of 12 3. Stationary Gamma Spectroscopy System The stationary gamma spectroscopy system consists of a HPGe detector in a low-background shield that is controlled by the Apex Gamma software.
UHHiS OmahaPubHePowerDlsliIti Partial Site Release Radiological Measurements FC-18-010 Revision 1 Page 7 of 12 Attachment 2 - In-Situ Gamma Spectroscopy Data The following is a summary of the gamma spectroscopy data obtained from the direct measurements obtained with the ISOCS characterized HPGe detector.
The only non-natural radionuclide detected was Cs-137. All other peaks in the spectrums can be attributed to the various radon decay chains.Location Apex Y Sample Sample Date/Time Nucllde Weighted Mean (pCI/g)MDA (pCi/g)1-1 24-Apr-18-200011 4/23/2018 14:28 CS-137<2.13E-1 2.13E-01 1-2 23-Apr-18-200005 4/23/2018 22:15 CS-137< 1.82E-1 1.82E-01 1-3 24-Apr-18-200018 4/24/2018 9:54 CS-137<2.18E-1 2.18E-01 1-4 24-Apr-18-200015 4/24/2018 7:47 CS-137<2.17E-1 2.17E-01 1-5 24-Apr-18-200016 4/24/2018 8:40 CS-137< 1.30E-1 1.30E-01 1-6 24-Apr-18-200017 4/24/2018 8:14 CS-137< 1.27E-1 1.27E-01 1-7 24-Apr-18-200008 4/23/2018 14:55 CS-137< 1.70E-1 1.70E-01 1-8 23-Apr-18-200003 4/23/2018 8:48 CS-137< 1.66E-1 1.66E-01 1-9 23-Apr-18-200006 4/23/2018 9:18 CS-137<2.06E-1 2.06E-01 1-10 24-Apr-18-200009 4/23/2018 13:34 CS-137< 2.09E-1 2.09E-01 1-11 24-Apr-18-200010 4/23/2018 14:01 CS-137< 2.05E-1 2.05E-01 1-12 23-Apr-18-200007 4/23/2018 9:47 CS-137< 1.23E-1 1.23E-01 1-13 24-Apr-18-200012 4/23/2018 13:05 CS-137< 2.25E-1 2.25E-01 1-14 23-Apr-18-200008 4/23/2018 10:43 CS-137 1.95E-01 1.80E-01 2-1 24-Apr-18-200021 4/24/2018 12:55 CS-137< 2.06E-1 2.06E-01 2-2 24-Apr-18-200022 4/24/2018 13:25 CS-137 2.82E-01 1.19E-01 2-3 Inaccessible 2-4 26-Apr-18-200002 4/25/2018 13:59 CS-137< 1.32E-1 1.32E-01 2-5 2-6 24-Apr-18-200023 4/24/2018 14:48 CS-137< 1.99E-1 1.99E-01 2-7 30-Apr-18-200022 4/30/2018 8:49 CS-137< 1.62E-1 1.62E-01 2-8 Inaccessible 2-9 Inaccessible 2-10 Inaccessible 2-11 30-Apr-18-200023 4/30/2018 8:19 CS-137< 1.68E-1 1.68E-01 2-12 24-Apr-18-200014 4/24/2018 10:20 CS-137< 2.54E-1 2.54E-01 2-13 24-Apr-18-200013 4/24/2018 10:46 CS-137 2.08E-01 1.83E-01 2-14 Inaccessible 2-15 24-Apr-18-200025 4/24/2018 13:45 CS-137< 1.83E-1 1.83E-01 3-1 30-Apr-18-200006 4/30/2018 9:19 CS-137< 1.77E-1 1.77E-01 3-2 30-Apr-18-200007 4/27/2018 13:22 CS-137< 2.60E-1 2.60E-01 3-3 30-Apr-18-200008 4/27/2018 10:09 CS-137< 1.79E-1 1.79E-01 3-4 30-Apr-18-200009 4/27/2018 10:36 CS-137 2.23E-01 1.68E-01 3-5 30-Apr-18-200010 4/27/2018 9:26 CS-137< 2.40E-1 2.40E-01 UHHSi OmbBPablkPimerDls^ftt Partial Site Release Radiological Measurements FC-18-010 Revision 1 Page 8 of 12 Attachment 2 - In-Situ Gamma Spectroscopy Data Location Apex Y Sample Sample Date/Time Nuclide Weighted Mean (pCI/g)MDA (pCI/g)3-6 30-Apr-18-200011 4/27/2018 14:12 CS-137<2.01E-1 2.01 E-01 3-7 30-Apr-18-200012 4/30/2018 10:15 CS-137< 2.64E-1 2.64E-01 3-8 30-Apr-18-200013 4/30/2018 9:45 CS-137<1.85E-1 1.85E-01 3-9 30-Apr-18-200014 4/27/2018 8:59 03-137< 2.30E-1 2.30E-01 3-10 30-Apr-18-200015 4/23/2018 13:23 CS-137< 2.29E-1 2.29E-01 3-11 30-Apr-18-200016 4/23/2018 14:01 CS-137< 2.29E-1 2.29E-01 3-12 30-Apr-18-200017 4/23/2018 9:47 CS-137< 2.46E-1 2.46E-01 3-13 30-Apr-18-200018 4/27/2018 12:54 CS-137< 1.52E-1 1.52E-01 3-14 30-Apr-18-200019 4/27/2018 8:00 CS-137< 1.37E-1 1.37E-01 iDem A 157 on UHHU Omaha Pobllc PmtrDbOict Partial Site Release Radiological Measurements FC-18-010 Revision 1 Page 9 of 12 Attachment 3 - Discrete Soil Sample Spectroscopy Data The following is a summary of the gamma spectroscopy data obtained from the discrete soil samples obtained in the same areas as the direct gamma radiation scan surveys. The only non-natural radionuclide detected was Cs-137. All other peaks in the spectrums can be attributed to the various radon decay chains.Data Point Latitude Longitude Sample Date/Time Volume (cm^)Mass (g)Density (g/cm^)Apex y Sample Nucllde Weighted Mean (pCI/g)MDA (pCI/g)L4-001-001S 41.52746389 96.09181872 4/23/2018 15:10 3500 3434.6 1.0 03-May-18-200001 CS-137 ND 5.51 E-02 L4-001-002S 41.54286300 96.09181872 4/24/2018 14:45 3500 4901.6 1.4 03-Mav-18-200003 CS-137 ND 3.82E-02 L4-001-003S 41.52472990 96.08910400 4/24/2018 10:00 3500 3696.7 1.1 03-Mav-18-200006 CS-137 6.02E-02 3.76E-02 L4-001-004S 41.53027878 96.09267161 4/24/2018 08:35 3500 3481.7 1.0 03-May-18-200007 CS-137 1.02E-01 4.11 E-02 L4-001-005S 41.52902872 96.09202292 4/24/2018 09:30 3500 3477.1 1.0 03-May-18-200008 CS-137 7.42E-02 4.09E-02 L4-001-006S 41.55302518 96.09286383 4/24/2018 08:10 3500 3675.0 1.1 03-May-18-200010 CS-137 8.24E-02 4.40E-02 L4-001-007S 41.52781463 96.09223917 4/24/2018 09:50 3500 3367.5 1.0 03-Mav-18-200011 CS-137 9.22E-02 4.88E-02 L4-001-008S 41.52383400 96.09214610 4/24/2018 14:40 3500 3903.8 1.1 03-May-18-200012 CS-137 6.04E-02 3.93E-02 L4-001-009S 41.52384390 96.09172170 4/24/2018 14:40 3500 4425.5 1.3 03-May-18-200013 CS-137 2.58E-02 2.84E-02 L4-001-010S 41.52459550 96.09015150 4/24/2018 14:25 3500 4526.8 1.3 03-May-18-200014 CS-137 1.62E-02 3.06E-02 L4-001-011S 41.52617890 96.09104800 4/24/201814:20 3500 4195.5 1.2 03-May-18-200015 CS-137 2.72E-02 6.36E-02 L4-001-012S 41.52439040 96.91739880 4/24/2018 14:30 3500 3445.5 1.0 03-May-18-200016 CS-137 5.13E-02 3.73E-02 L4-001-013S 41.52378450 96.08908590 4/24/2018 14:30 3500 3594.5 1.0 03-May-18-200017 CS-137 5.45E-02 4.23E-02 L4-001-014S 41.52419030 96.09050290 4/24/2018 14:35 3500 3258.0 1.0 07-IVIay-18-200009 CS-137 1.58E-01 4.87E-02 L4-002-001S 41.52472930 96.08873880 4/24/2018 20:15 3500 3520.0 1.0 07-May-18-200010 CS-137 1.20E-01 4.75E-02 L4-002-002S 41.52673700 96.08830300 4/23/2018 22:50 3500 2868.9 1.0 07-May-18-200016 CS-137 1.98E-01 5.13E-02 L4-002-003S 41.53085020 96.09182815 4/24/2018 09:35 3500 3551.4 1.0 08-May-18-200001 CS-137 2.44E-02 3.96E-02 L4-002-004S 41.52541750 96.08855560 4/23/2018 09:40 3500 3227.7 1.0 08-May-18-200002 CS-137 1.58E-01 5.00E-02 L4-002-005S 41.58009145 96.09086995 4/24/2018 13:15 3500 4175.8 1.2 08-May-18-200003 CS-137 ND 4.28E-02 L4-002-006S 41.52650610 96.08964100 4/23/2018 10:30 3500 3396.3 1.0 08-May-18-200004 CS-137 1.39E-01 5.18E-02 BppB Onu^eMllePowerDisbkt Partial Site Release Radiological Measurements FC-18-010 Revision 1 Page 10 of 12 Attachment 3 - Discrete Soil Sample Spectroscopy Data Data Point Latitude Lonqitude Sample Datemme Volume (cm^)Mass (g)Density (fl/cm^)Apex Y Sample Nucllde Weighted Mean (pCi/g)MDA (pCi/g)L4-002-007S 41.52549980 96.08917500 4/23/2018 10:05 3,500 3,473.5 1.0 08-Mav-18-200005 CS-137 1.35E-01 4.98E-02 L4-002-008S 41.52842680 96.08862760 4/23/2018 13:40 3,500 4,471.7 1.3 08-Mav-18-200021 CS-137 ND 4.10E-02 L4-002-009S 41.52894910 96.09057220 4/24/201810:20 3,500 3,022.1 1.0 08-Mav-18-200022 CS-137 1.82E-01 5.41 E-02 L4-002-010S 41.52821400 96.08905020 4/23/2018 13:52 3,500 3,124.9 1.0 09-May-18-200001 CS-137 1.85E-01 4.65E-02 L4-002-011S 41.52524500 96.08890600 4/23/2018 09:45 3,500 3,382.4 1.0 09-Mav-18-200002 CS-137 1.45E-01 4.28E-02 L4-002-012S 41.52430600 96.08860000 4/24/2018 08:45 3,500 3,661.2 1.0 10-Mav-18-200001 CS-137 1.36E-01 4.41 E-02 L4-002-013S 41.52456100 96.08846830 4/24/2018 08:30 3,500 3,582.0 1.0 10-Mav-18-200002 CS-137 1.56E-01 5.10E-02 L4-002-014S 41.52930370 96.08925500 4/24/2018 13:50 3,500 5,079.6 1.4 10-May-18-200003 CS-137 ND 3.67E-02 L4-003-001S 41.52273010 96.08856580 4/27/2018 13:00 3,500 2,972.6 1.0 10-Mav-18-200004 CS-137 1.91 E-01 5.03E-02 L4-003-002S 41.52005310 96.08926200 4/27/2018 13:50 3,500 2,838.1 1.0 14-IVlay-18-200001 CS-137 1.93E-01 6.19E-02 L4-003-003S 41.51040490 96.09052570 4/27/2018 10:50 3,500 2,725.4 1.0 14-May-18-200002 CS-137 2.04E-01 5.94E-02 L4-003-004S 41.51931700 96.08846500 4/27/2018 10:30 3,500 2,787.8 1.0 14-May-18-200003 CS-137 2.09E-01 6.40E-02 L4-003-005S 41.51756911 96.09029510 4/26/2018 14:50 3,500 3,386.8 1.0 14-May-18-200008 CS-137 1.29E-01 3.69E-02 L4-003-006S 41.52192840 96.09040435 4/27/2018 13:05 3,500 4,098.2 1.2 15-May-18-200001 CS-137 5.67E-02 2.98E-02 L4-003-007S 41.52288801 96.08990000 4/27/201813:00 3,500 3,034.3 1.0 15-May-18-200002 CS-137 1.53E-01 5.56E-02 L4-003-008S 41.52242320 96.08067520 4/27/2018 12:55 3,500 3,251.5 1.0 15-May-18-200016 CS-137 1.25E-01 4.68E-02 L4-003-009S 41.51717400 96.09048800 4/26/2018 14:30 3,500 3,313.6 1.0 16-Mav-18-200001 CS-137 ND 6.17E-02 L4-003-010S 41.51683500 96.09041390 4/26/2018 14:10 3,500 3,468.6 1.0 16-May-18-200002 CS-137 ND 5.43E-02 L4-003-011S 41.51856450 96.08839270 4/27/2018 10:20 3,500 3,343.2 1.0 17-May-18-200001 CS-137 5.21 E-02 4.64E-02 L4-003-012S 41.52109175 96.09040580 4/27/2018 13:10 3,500 3,121.1 1.0 17-May-18-200002 CS-137 1.42E-01 4.07E-02 L4-003-013S 41.52127550 96.08839200 4/27/2018 13:20 3,500 3,976.8 1.1 17-May-18-200003 CS-137 8.43E-02 3.00E-02 L4-003-014S 41.51681850 96.08904200 4/26/2018 13:54 3,500 3,398.4 1.0 21-May-18-200002 CS-137 5.56E-02 4.51E-02 NO = None Detected; All latitude values are North, and all longitude values are West.
IffWU Partial Site Release Radiological Measurements Oma/aPatHc Power Oisirki FC-18-010 Revision 1 Page 11 of 12 Attachment 5 - Gross Gamma Radiation Scan Background Calculations Requires Loc.Avg.Requires Loc.Avg.Location Investigate Type CRM Location Investigate Type CRM 1-1 0 Field 8,641 2-9 0 Trees 8,959 1-2 0 Field 8,544 2-10 0 Field 9,065 1-3 0 Field 8,543 2-11 0 Field 9,755 1-4 0 Field 9,193 2-12 0 Field 9,790 1-5 0 Field 8,787 2-13 0 Field 9,913 1-6 0 Field 9,107 2-14 0 Trees 9,860 1-7 0 Field 8,689 3-1 0 Field 9,732 1-8 0 Field 8,494 3-2 0 Field 9,348 1-9 0 Field 8,729 3-3 0 Field 9,606 1-10 0 Field 8,448 3-4 0 Field 9,280 1-11 0 Field 8,452 3-5 0 Field 9,267 1-12 0 Field 8,503 3-6 0 Sand 8,894 1-13 0 Field 8,480 3-7 0 Field 9,702 1-14 0 Field 9,107 3-8 0 Field 9,378 2-1 0 Trees 9,664 3-9 0 Field 9,553 2-2 0 Trees 8,948 3-10 0 Field 9,578 2-3 0 Trees 8,785 3-11 0 Field 9,652 2-4 0 Field 9,963 3-12 0 Field 9,568 2-5 0 Trees 9,460 3-13 0 Field 8,768 2-6 0 Field 9,793 3-14 0 Field 9,458 2-7 0 Field 9,855 2-10 0 Field 9,065 2-8 0 Trees 9,983 2-11 0 Field 9,755 HFKII OaalaM^leFewerDlstiicI Partial Site Release Radiological Measurements FC-18-010 Revision 1 Page 12 of 12 Attachment 5 - Gross Gamma Radiation Scan Background Calculations Summary of N a! Background Data Location Type Avg.Bkgd (cpm)StDev (cpm)Median (cpm)MDCR (cpm)Action Level (cpm)Field 9,161 587 9,150 2,606 11,767 Trees 9,743 1,280 10,020 2,680 12,423 Sand 8,926 911 8,580 2,553 11,479 Action Level = MDCR + Average Background
,2 MDCR=MDCR = minimum detectable count rate (cpm)a = probability of a Type I (false positive) error P = probability of a Type II (false negative) error Zi-a = (1 ~ ci) quantile of the standard normal distribution Z].p = (1 - P) quantile of the standard normal distribution ts = sample count time (min)tb = background count time (min)Rb = background count rate (cpm).