3F0625-01, Attachment 12: Tsd - Evaluation of Radiochemical Analysis of Well Water Samples from the Proposed Partial Site Release at the Crystal River 3 Nuclear Generating Plant
| ML25170A032 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 06/18/2025 |
| From: | Bland J ADP CR3, Chesapeake Nuclear Services |
| To: | Office of Nuclear Material Safety and Safeguards, Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML25170A017 | List: |
| References | |
| 3F0625-01 | |
| Download: ML25170A032 (1) | |
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ADP CR3, LLC 15760 West Power Line Street l Crystal River, FL 34428 ADP CR3, LLC DOCKET NUMBER 50-302 / DOCKET NUMBER 72-1035 LICENSE NUMBER DPR - 72 ATTACHMENT 12 TSD - Evaluation of Radiochemical Analysis of Well Water Samples from the Proposed Partial Site Release at the Crystal River 3 Nuclear Generating Plant 3F0625-01 / Attachment 12 A1
3F0625-01 / Attachment 12 / Page 1 of 6 ADP CR3, LLC A1 15760 West Power Line Street I Crystal River, FL 34428 Technical Support Document Evaluation of Radiochemical Analysis of Well Water Samples from the Proposed Partial Site Release at the Crystal River 3 Nuclear Generating Plant May 27, 2025 Performed by: --~----------
]. Stewart Bland, CHP Chesapeake Nuclear Services, Inc.
Reviewed by: -~C~i~A~u~JJ~t.~ZJ~~::'.'.-
~:....:.* __::-~-
Claude Wiblin, CHP Chesapeake Nuclear Services, Inc.
Apprnvcd by ~
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Leon BryanAkinsJr_
FSS/ RPM, ADP CR3 Decommissioning
3F0625-01 / Attachment 12 / Page 2 of 6 Evaluation of Radiochemical Analysis of Well Water Samples from the Proposed Partial Site Release at the Crystal River 3 Nuclear Generating Plant The following addresses issues raised during the NRC's audit of the proposed Partial Site Release (PSR),
pertaining to the Crystal River Unit 3 Nuclear Generating Plant (CR3's) position of false positive measurements of radionuclide concentrations in groundwater samples. Of primary concern were groundwater samples collected from wells within the PSR area. As detailed in the CR3's PSR request, two rounds of groundwater samples were submitted to General Engineering Laboratories (GEL) for radionuclide analysis. In keeping with MARLAP guidance, the critical level, referred to as the Le value, has been used as the decision point for identifying a positive measurement, i.e., any value above the critical level (Le) is considered a positive measurement. These two sampling campaigns and analytical results identified several CR3 Radionuclides of Concern (ROCs) that would be considered positive measurements, i.e., above respective Le values, but below the minimum detectable concentrations (MDC). This situation (Le <
measured concentration < MDC) is not unexpected, recognizing the statistical basis for calculating the Le with a 5% false positive rate. In this situation, a follow up assessment or evaluation is needed to support a conclusion of a false positive.
Based on a thorough review of the analytical data and associated quality control measures, the following rationale is presented to support the CR3 position that certain radioanalytical concentrations, which were above reported Le values, are considered false positive results.
The radiochemical analytical results for groundwater samples collected from key indicator wells at CR3, which included wells CCRW-29, TWI-2R-A and TWI-3-A located within the PSR area, are evaluated below.
Table 1 summarizes the results from sampling conducted in January 2024; Table 2 summarizes results from follow-up sampling conducted in February 2024. Highlighted values are above the respective Le value for the analysis; all others were below Le values. All values were below respective MDC values.
Table 1,January 2024 Sample Results Summary (values highlighted were above Le but below MDC values)
Radionuclide CR3-4 CR3-5 CR3-6D CCRW-29 TW1-2R-A TWI-3-A (pCi/1)
(pCi/1)
(pCi/1)
(pCi/1)
(pCi/1)
(pCi/1)
Americium-241 0.00743 0.0192 0.0329 0.0176 0.0141 0.0145 Carbon-14
-22.8 1.72 41.6 7.28 33.3
-21.0 Cesium-137 0.199 0.000
-0.567 0.499
-0.949 0.352 Cobalt-60 0.107
-0.0852 0.687
-0.269 1.47 0.402 Europium-152
-3.69
-2.35 0.806
-1.27
-1.66 4.91 Europium-154
-1.34
-1.69 4.47
-0.454
-3.01
-0.114 lron-55 3.80
-8.45
-15.1
-1.46 0.658
-7.02 Nickel-59
-9.74 2.02
-1.46 0.367
-1.46
-5.95 Nickel-63 1.31 0.399
-0.933
-1.18 1.07
-1.06 Plutonium-239
-0.0124
-0.00463
-0.0294
-0.0127 0.00668 0.000556 Strontium-90 0.290
-1.58 0.0179 0.0871
-0.505 0.138 T echnetium-99
-3.69 7.14 5.39 4.25
-8.30 1.33 Tritium
-20.1 44.9
-27.7 32.8 12.3 44.6 1
3F0625-01 / Attachment 12 / Page 3 of 6 Table 2, February 2024 Resampling Results Summary (values highlighted were above Le but below MDC values)
Radionuclide CR3-4 CR3-6D TWI-2R-A TWI-3-A (pCi/1)
(pCi/1)
(pCi/1)
(pCi/1)
-0.004
-0.002 0.046 0.015 Carbon-14
-16.7 31.4 3.28 8.420 Cesium-137 0.722
-2.09
-1.22 0.607 Cobalt-60 2.60
-2.99 0.751 0.117 Europium-152 2.40
-3.87
-2.24 3.710 Europium-154
-7.79 7.09
-2.08 2.44 Iron-55
-104.
-74.8
-102
-75.4 Nickel-59
-19.7
-1.09
-2.29
-1.44 Nickel-63
-2.42 21.1 4.25 8.70 Plutonium-239 0.020
-0.010 0.016 0.111 Strontium-90
-0.425 0.904 0.480
-0.144 Technetium-99 28.9 39.3 27.3
-7.49 Tritium 76.0 10.4 3.91
-74.9 Note: Wells CR3-5 and CCRW-29 were not resampled; no analytical results required additional evaluation.
Evaluation of Radiochemical Analytical Measurements The following evaluates the analytical measurement results, comparing the initial sample and the follow-up resampling. Any measurement above its Le value is considered a positive, based on the results of the single measurement alone. However, recognizing the possibility of a false positive (nominal 5% based on a 1-tailed statistical test upon which the Le value is determined) and the fact that these analytical measurements are, or can be, challenging due to the very low radionuclide concentration and required chemical processes, identified positive measurements requires careful examination in determining if the radionuclide detection is a true or false positive measurement. Analytical measurements for other key ROCs are included as additional indicators of the overall absence of ROCs in the sample, with attention given to tritium, which, because of its mobility, is considered the primary indicator for groundwater contamination.
WELL TWI-3-A The initial sample (collected on 01 / 11 / 24) showed detectable level ofEu-152 at 4.91 pCi/ 1 with a Le value of 4.45 pCi/ 1 and MDC of 9.55 pCi/ 1. This was the only ROC detected above the Le. The following summarizes analytical results for other ROCs:
Tritium level was below the Le at a measured value of 44.6 pCi/ 1 with an Le value of 87.7 pCi/ 1.
Sr-90 was measured at 0.138 pCi/ 1 with an Le value of 0.487 pCi/ 1.
Ni-63 was measured at -1.06 pCi/ 1 with an Le value of 1.78 pCi/ 1.
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3F0625-01 / Attachment 12 / Page 4 of 6 For the resample of Well TWI-3-A, the measured value for Eu-152 was 3.71 pCi/ 1, which was below its Le value of 4.36 pCi/ 1; the MDC value was 9.36 pCi/ 1. However, Ni-63 was detected at 8.7 pCi/ 1, which was above its Le value of 7.23 pCi/ 1; the MDC value was 14.9 pCi/1. Additional analytical results for the resample included:
Tritium was measured at -74.9 pCi/ 1 with an Le value of 102 pCi/ 1.
Sr-90 was -0.144 pCi/ 1 with an Le value of 0.230 pCi/ 1.
Ni-63 was 8.7 pCi/ 1 with an Le value of7.23 pCi/ 1.
The initial detection ofEu-152 is considered a false positive. When multiple analyses are performed, with conflicting results, as is the case here, the average of the two measurements can be used for a comparison. In this case, the average of the two Eu-152 values (4.91 and 3.71 pCi/ 1) is 4.31 pCi/ 1. This value is less than both of the Le value for the analyses.
The initial sample reported a Ni-63 value of -1.06 pCi/ 1 with an Le value of 1.78 pCi/ 1. However, the reanalysis reported a level of 8.7 pCi/ 1 with an Le value of 7.23 pCi/ 1. Similarly, an averaging of the values (-
1.06 and 8. 7) would yield a value of 7.64 pCi/ 1. While this value is above the initial sample Le, it is below the 2nd sample Le. In this case, the initial sample had a lower Le value and its results were below the Le. In this case, priority is given to the initial analysis with its lower Le value. Therefore, the Ni-63 detection is the reanalysis is considered a false positive.
Tritium, which serves as the primary indicator of contamination, was not detected in either sample analyses.
For reasons discussed above, the positives as measured for Well TWI-3-A (initial for Eu-152 and reanalysis for Ni-63) are considered false positives.
WELL TWI-2R-A The initial sample (collected on 01 / 11 / 24) showed detectable level of C-14 at 33.3 pCi/ 1 with an Le value of 26.5 pCi/ 1 and MDC of 55.3 pCi/ 1. This was the only detected ROC. The following summarizes analytical results for other ROCs:
Tritium level was measured at 12.3 pCi/ 1 with an Le value of 86.4 pCi/ 1.
Sr-90 was measured at -0.505 with an Le value of 0.289 pCi/ 1.
Ni-63 was measured at 1.07pCi/ l with an Le value of 1.80 pCi/ 1.
For the resample of Well TWI-2R-A, the measured value for C-14 was 3.28 pCi/ 1, which was below its Le value of 34.7 pCi/ 1 and MDC value of 72.0 pCi/ 1. However, Sr-90 was detected at 0.480 pCi/ 1, which was above the Le value of 0.235 pCi/ 1; the MDC value was 0.487 pCi/ 1. The following summarizes analytical results for other ROCs:
Tritium was 3.91 pCi/ 1 with an Le value of 105 pCi/ 1.
Ni-63 was 4.25 pCi/ 1 with an Le value of 7.60 pCi/ 1.
The initial detection of C-14 is considered a false positive. When multiple analyses are performed, with conflicting results, as is the case here, the average of the two measurements can be used for a comparison. In this case, the average of the two C-14 values (33.3 and 3.28 pCi/ 1) is 18.3 pCi/ 1. This value is less than both Le values for the analyses.
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3F0625-01 / Attachment 12 / Page 5 of 6 The initial sample reported a Sr-90 value of -0.505 pCi/ 1 with an Le value of 0.289 pCi/ 1. However, the reanalysis reported a level of 0.48 pCi/ 1 with an Le value of 0.235 pCi/ 1. Similarly, an averaging of the values
(-0.505 and 0.48) would yield a value of -0.108 pCi/ 1. This value is less than both Le values for the analyses.
Tritium, which serves as the primary indicator of contamination, was not detected in either sample analyses.
For reasons discussed above, the positives as measured for Well TWI-3-A (initial for C-14 and reanalysis for Sr-90) are considered false positives.
WELLCR3-6D The initial sample (collected on 01 / 10/ 24) showed detectable level ofEu-154 at 4.47 pCi/ 1 with a Le value of 3.28 pCi/ 1 and MDC of 7. 77 pCi/ 1. This was the only detected ROC. The following summarizes analytical results for other ROCs:
Tritium level was measured value of -27.7 pCi/ 1 with an Le value of 123 pCi/ 1.
Sr-90 was measured at 0.0179 with an Le value of 0.790 pCi/ 1.
Ni-63 was measured at -0.933 pCi/ 1 with an Le value of 2.34 pCi/ 1.
For the resample of Well CR3-6D, the measured value for Eu-154 was 7.09 pCi/ 1, which was below the Le value of10.6 pCi/ 1; the MDC value was 23.7 pCi/ 1. However, Ni-63 was detected at 21.1 pCi/ 1, which was above the Le value of 15.6 pCi/ 1; the MDC value was 32.0 pCi/ 1. And, Sr-90 was detected at 0.904 pCi/ 1, which was above its Le value of0.518 pCi/ 1; the MDC value was 1.07 pCi/ 1.
Tritium was 10.4 pCi/ 1 with an Le value of 101 pCi/ 1.
The initial detection ofEu-154 is considered a false positive. When multiple analyses are performed, with conflicting results, as is the case here, the average of the two measurements can be used for a comparison. In this case, the average of the two Eu-154 values (4.47 and 7.09 pCi/ 1) is 5.78 pCi/ 1. While 5.78 pCi/ 1 is above the Le value for the initial sample, this value is below the average Le value of 6.94 pCi/ 1 for the combined results.
The initial sample reported a Ni-63 value of -0.933 pCi/ 1 with an Le value of 2.34 pCi/ 1 and an MDC of 4.82 pCi/ 1. However, the reanalysis reported a level of 21.1 pCi/ 1 with an Le value of 15.6 pCi/ 1; the MDC value was 32.0 pCi/ 1. The averaging of the values (-0.933 and 21.1) is 10.1 pCi/ 1. This value is above the reported Le values. A review of the sample analytical data indicated that this reanalysis had a condition where there was a limited sample volume, and the sample extraction was counted on a detector with a slightly higher background rate than the other analyses. Considering these potential limitations, more weight is given to the initial analyses which showed no detectable Ni-63 with much lower measured value and lower Le value.
Based on the above, the reanalysis for Ni-63 is considered a false positive.
For Sr-90, the average of the two sample measurements (0.0179 and 0.904 pCi/ 1) is 0.461 pCi/ 1. This value is below the Le values for both analyses. The reanalysis for Sr-90 had the same issues as addressed above for the Ni a limited sample volume and higher detector background. Based on the average value being below the Le and the concerns regarding the reanalysis, the Sr-90 results for the reanalysis is considered a false positive.
Tritium, which serves as the primary indicator of contamination, was not detected in either sample analyses.
For reasons discussed above, the positives as measured for Well CR3-6D (initial for Eu-154 and reanalysis for Ni-63 and Sr-90) are considered false positives.
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3F0625-01 / Attachment 12 / Page 6 of 6 WELLCR3-4 The initial sample (collected on 01 / 10/ 24) showed detectable level of Sr-90 at 0.290 pCi/1 with a Le value of 0.272 pCi/ 1 and MDC of 0.563 pCi/ 1. This was the only ROC detected above the Le. The following summarizes analytical results for other ROCs:
Tritium level was measured value of -20.1 pCi/ 1 with an Le value of 121 pCi/ 1.
Ni-63 was measured at 1.31 pCi/ 1 with an Le value of 1.78 pCi/ 1.
For the resample of Well CR3-4, the measured value for Sr-90 was -0.425 pCi/ 1, which was below the Le value of 0.351 pCi/ 1. No other ROCs were detected above their Le values.
Tritium was 76.0 pCi/ 1 with an Le value of 126 pCi/ 1.
When multiple analyses are performed, with conflicting results, as is the case here, the average of the two measurements can be used for a comparison. In this case, the average of the two Sr-90 values (0.290 and
-0.425 pCi/1) is -0.068 pCi/ 1. This value is below both Le values. The initial detection of Sr-90 is considered a false positive.
Conclusion Based on the evaluations above, the groundwater analysis for the ROCs with measured concentrations above respective Le values are false positives. There were no positively identified ROCs in groundwater for the wells sampled during the identified two sampling campaigns in January and February 2024. The groundwater is considered NOT IMPACTED in the areas identified in the PSR request.
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