ML25156A235
| ML25156A235 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 06/17/2025 |
| From: | Reactor Decommissioning Branch |
| To: | |
| Shared Package | |
| ML25156A231 | List: |
| References | |
| EPID L-2025-LLA-0033 | |
| Download: ML25156A235 (1) | |
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CR3 Partial Site Release Audit Topics Summary May 12-29, 2025 Page 1 of 16 Attachment No.
Discussion Topic NRC Staff Observations &
Closure Actions 1.i Describe the conceptual site model for brackish groundwater and how it relates to water quality in the areas of the partial site release. Clarify how the conceptual site model is consistent with the water quality data in Haley & Aldrich 2024* and whether the groundwater quality in the Partial Site Release (PSR) areas has no uses for drinking water, irrigation, or stock.
- Haley & Aldrich 2024, Sodium and Chloride Groundwater Data from Wells Within NRC Licensed Area Accelerated Decommissioning Partners (ADP), Crystal River Unit 3; Technical Memorandum dated May 29, 2024, File No. 134300-0.
Observations: ADP proposed that the groundwater residual radioactivity results in Table 2-26 of LTP Rev 1 are false positives. If the indistinguishable from background assessment is substantiated, then there is no need to address water quality (i.e., brackish or freshwater) in Phase II PSR areas. See item 2.i. for groundwater portion and item 11.i-ii for soils portion.
If water quality and use need to be determined, then Haley & Aldrich (May 2024) will need to be provided since it is not on the docket.
Action: This item is closed due to resolution of item 2.i indicting that Table 2-26 results are likely false positives. Haley & Aldrich (May 2024) does not need to be provided for the Phase II PSR.
1.ii Clarify how the boundary and initial conditions in the brackish water model documented in Enclosure 8 of the Phase II PSR represent conditions across the proposed partial site release areas (NIA-01 through NIA-06, R16Y, Coal Ash Storage Area (CASA), SEAL).
Observations: The need to address this item was dependent on the resolution of item 2.i which is closed-pending based on ADP providing support that Table 2-26 groundwater results above the critical level are likely false positives. See item 2.i.
Action: This item is closed.
CR3 Partial Site Release Audit Topics Summary May 12-29, 2025 Page 2 of 16 No.
Discussion Topic NRC Staff Observations &
Closure Actions 2.i Reconcile the groundwater results in Table 2-26 of License Termination Plan (LTP),
Rev. 2 from the proposed partial site release areas (or near the proposed boundary) with the designation of non-impacted for the partial site release areas (particularly the CASA). Options for the licensee to address results in Table 2-26 of LTP Rev. 2 include: (i) if the licensee considers these three results to be statistical anomalies, then more than one sampling event may be necessary; or (ii) if the licensee considers these results as detections of plant-related radioactivity, then a dose estimate for existing groundwater contamination should be provided in the Phase II PSR.
Observations: ADP stated that their position remains that there is no residual radioactivity in the groundwater of the PSR areas. MARLAP guidance indicates that analytical results between critical levels (Lc) and minimum detectable concentrations (MDC), while unreliable, mean that radionuclides were detected (i.e., statistically above the signal level associated with blanks). Considering that the values of analytical results are based on statistical assessment, ADP chose to evaluate the possibility that results in Table 2-26 of the LTP Rev 2 are false positives.
Response Document: ADP made the Technical Support Document (TSD) "Evaluation of Radionuclide Analysis of Well Water Samples from the Proposed Partial Site Release at the Crystal River 3 Nuclear Generating Plant" available for staff viewing in the online portal. The document includes the data from Table 2-26 of LTP Rev. 2 and results from a follow-up sampling event; the data includes the results along with a posteriori values for the Lc and MDC. The support included several considerations, including averages from the two data sets being below the value associated with the critical level, radionuclide results above the critical level in the first data set were below the critical level in the second data set, and all results were near the critical level or below. In addition, ADP suggested that tritium, as an indicator radionuclide for residual radioactivity, was below the Lc values in all samples for both sampling events.
Action: The item will be closed when ADP attaches the TSD to the PSR application resubmittal and revises the text, as appropriate, in other parts of the PSR application.
2.ii Confirm that Wells 4, 5, and 6D in Table 2-26 of LTP Rev 2 refer to the CR3 series of wells, and not to the MW series of wells.
Observations: ADP confirmed that the results in Table 2-26 of LTP Rev 2 refer to the well series CR3-xx. The document provided for item 2.i confirmed that wells 4, 5, and 6D refer to CR3-4, CR3-5, and CR3-6d.
Action: The item is closed based on the TSD provided in item 2.i.
CR3 Partial Site Release Audit Topics Summary May 12-29, 2025 Page 3 of 16 No.
Discussion Topic NRC Staff Observations &
Closure Actions 3.i MARSSIM, Section 4.5, recommends background reference areas have similar physical, chemical, geological, radiological, and biological characteristics as the survey units being evaluated. Four background reference areas were selected to capture the physical and chemical variability of the site to support the Phase I PSR release including non-industrialized and tidal flats areas.
Explain how the physical and geological characteristics for the background reference areas (BRAs) are representative of the survey units identified in the Phase II PSR.
Observations: ADP plans to split RA-03 and RA-04 into four reference areas and conduct a resampling effort in these areas to reestablish the background concentrations for use in the indistinguishable from background determination.
These new reference areas have similar characteristics to the survey units in the Phase II PSR. ADP will define the new reference areas in the PSR, which will resolve questions of whether the tidal flats reference areas were applicable to industrial area survey units.
Action: The item will be closed when ADP adequately revises the application to include a description of the updated BRA.
3.ii BRA data was provided in Partial Site Release of the Crystal River Energy Complex Radiological Survey Final Report, Table 4-3, Summary of Gamma Spectroscopy Results for Samples Comprising the Statistical Sample Population - Background Assessment.
Minimum Detectable Concentration (MDC) values were reported for sample results less than the MDC for Cs-137 and Co-60. The results, including those reported as the MDC, were used to perform statistical tests and determine the Cs-137 background value used as a comparison point for the Phase II PSR. Use of the MDC rather than actual concentrations, biased the background concentration high in the non-conservative direction. Propose an approach to resolve the bias in the BRA concentration used as the basis for determining indistinguishable from background.
Observations: ADP chose to reestablish the BRAs and conduct a new sampling campaign in the new background reference areas. The samples will be analyzed onsite for Cs-137 allowing the licensee to use actual sample results to establish the concentration that is indistinguishable from background and eliminate the bias caused by using MDC values for results less than the MDC.
Action: The item will be closed when ADP adequately revises the application to include an updated BRA analysis.
CR3 Partial Site Release Audit Topics Summary May 12-29, 2025 Page 4 of 16 No.
Discussion Topic NRC Staff Observations &
Closure Actions 3.iii The existing survey unit data (NIA, CASA, R16Y and SEAL) reported the actual results for all radionuclides whether above or below the Minimum Detectable Activity (MDA).
While this is the appropriate approach to reporting data, it is inconsistent with the reporting and analysis of data for the BRAs.
Since the data sets are not equivalent, a direct comparison of the data is not appropriate. Propose an approach to resolve the inconsistencies between the BRA and survey unit data sets.
Observations: ADP chose to reestablish the BRAs and conduct a new sampling campaign. The licensee will be using actual sample results for their statistical background concentration determination.
This approach is consistent with the use of actual sample results in the Phase II PSR survey units.
Action: The item will be closed when ADP adequately revises the application to include an updated BRA analysis.
3.iv The BRA concentrations were based on judgmental rather than random sampling, which is inconsistent with the use of non-parametric statistics (e.g., indistinguishability from background). Justify the use of judgmental rather than random samples.
Observations: ADP chose to reestablish the BRAs and conduct a new sampling campaign. ADP will divide RA-03 and RA-04 into four reference areas.
A set of random samples locations will be generated along with a back-up set of random sample locations. The back-up locations will be used where samples cannot be collected at the initial random sample coordinates. The use of random sampling with the new sampling campaign would resolve the issue of using judgmental sampling in non-parametric statistics. ADP will verify the number of samples collected generates sufficient power in the analysis.
Action: The item will be closed when ADP adequately revises the application to include an updated BRA analysis.
3.v The Phase I PSR did not include a Kruskal-Wallis to evaluate the variability between the reference areas. In addition, there was no mention of the WRS and Quantile test in the Phase II PSR. Justify excluding these tests from the indistinguishable from background analysis.
Observations: ADP chose to reestablish the BRAs and conduct a new sampling campaign. Using this new data and the data from the Class 3 survey units, the licensee will conduct the appropriate statistical tests to demonstrate that the residual radioactivity in the survey units is indistinguishable from background.
Action: The item will be closed when ADP adequately revises the application to include an updated BRA analysis.
CR3 Partial Site Release Audit Topics Summary May 12-29, 2025 Page 5 of 16 No.
Discussion Topic NRC Staff Observations &
Closure Actions 4.i.a Isolation and controls are established to prevent the spread of contamination from areas of the site under active decommissioning to those previously released. Provide isolation and control plans for the proposed site boundary and evaluations of all migration pathways from the remaining onsite areas to the proposed partial site release areas.
Observations: ADP will summarize in the revised PSR an evaluation of the migration pathways from the site to the adjacent PSR areas. The evaluation will include isolation and control measures and evaluations of both surface and subsurface migration pathways. The discussion will consider both natural processes and decommissioning activities and will include plans for isolation control measures for any possible sources. Additional specifics are included in items 4.i.b, 4.i.c, and 4.ii.
Action: The item will be closed when ADP adequately revises the application to summarize an evaluation of the migration pathways and any isolation and control measures to prevent the spread of residual radioactivity from the Protected Area to the adjacent PSR areas.
4.i.b The final status survey for R16Y occurred in October 2023, and for CASA, and SEAL in November 2024. Describe the isolation and controls implemented to prevent recontamination of survey units following the final status surveys.
Observations: ADP provided NS-FSS-04, "Isolation and Controls of Areas for Final Status Survey," which discusses post FSS controls in place for survey units.
Action: The item will be closed when ADP adequately revises the application to include a summary of the isolation and controls in NS-FSS-04, "Isolation and Controls of Areas for Final Status Survey."
4.i.c Describe the controls in place to prevent the recontamination of released survey units during transport of radioactive materials from the Protected Area through the Phase II PSR survey units following approval of the PSR.
Observations: ADP provided NS-FSS-04, "Isolation and Controls of Areas for Final Status Survey" which discusses rerouting of haul paths through areas within the revised site boundary.
Action: The item will be closed when ADP adequately revises the application to summarize the plans for haul path use within the Protected Area to prevent recontamination of PSR survey units.
CR3 Partial Site Release Audit Topics Summary May 12-29, 2025 Page 6 of 16 No.
Discussion Topic NRC Staff Observations &
Closure Actions 4.ii Provide a discussion of how the environmental monitoring program and offsite dose calculation manual still meet the 10 CFR 50.83(a)(1)(iv) requirements for offsite effluents for the proposed site boundary when considering the groundwater pathway.
Understanding: ADP will revise the PSR to indicate that all migration pathways from the remaining site area to the partial site release areas were evaluated. The evaluation will include the groundwater pathway to all adjacent PSR areas, but particularly from the remaining site area to the southeast into NIA-06 considering groundwater flow patterns at the site. As indicated in the PSR, no revision to the ODCM is expected.
Action: The item will be closed when ADP adequately revises the application to indicate that all migration pathways from the remaining site area to the partial site release areas were evaluated.
5.i MARSSIM examples of Class 3 survey areas include buffer zones around Class 1 and Class 2 areas. The southeast corner of NIA-04 and the southwest corner of NIA-05 were bounded by DISC-02 through DISC-10, which were designated Class 1 and Class 2 survey units in the LTP, Rev. 2. Justify the classification for the portions of NIA-04 and NIA-05 adjacent to Class 1 and Class 2 areas as non-impacted.
Observations: ADP maintains that the Class 1/2 residual radioactivity is in the underwater sediment in the Discharge Canal which borders NIA-04 and NIA-05. ADP does not plan to remediate this area at this time. If remediation occurs in the Discharge Canal, ADP will conduct activities on the North side of the canal and implement radiological controls.
Action: The item will be closed when ADP revises their application to include an explanation of the nature of the residual radioactivity in the Discharge Canal Class 1 survey units adjacent to NIA-04 and NIA-05 and radiological controls to be implemented if remediation occurs in the PSR.
5.ii reclassified R16Y as non-impacted based on information in the Historical Site Assessment (HSA) and further characterization that was completed during the CHAR-01 characterization survey and the FSS. According to the HSA, the area was used for radioactive material container shipping storage during Refuel Outage #16 and was designated as MARSSIM Class 3. Non-impacted areas are those with no reasonable potential for residual radioactivity in excess of natural background or fallout levels (10 CFR 50.2).
Clarify the rationale for reclassification of R16Y.
Observations: The R16Y will remain a Class 3 area. The statement relating to the downgrading of R16Y to a non-impacted area will be removed from.
Action: The item will be closed when ADP adequately revises the application to remove the reference to downgrading the survey unit from Class 3 to non-impacted.
CR3 Partial Site Release Audit Topics Summary May 12-29, 2025 Page 7 of 16 No.
Discussion Topic NRC Staff Observations &
Closure Actions 6
The PSR does not specify a surface to detector distance or a scan speed for the R16Y and NIA survey units. The distance of the detector from the surface and the scan speed can impact detector sensitivity.
Provide the surface to detector distance and the scan speed used for the R16Y and non-impacted survey units.
Observations: ADP agreed to incorporate the detector distance and scan speed in the application.
Action: The item will be closed when ADP adequately revises the application to include the scan speed and the detector distance in the survey unit Final Status Survey Reports (FSSRs) for R16Y and the NIA survey units.
7 The PSR did not include a discussion of the determination of relative shift, or the input data (i.e., upper bound of the gray region (UBGR), lower bound of the gray region (LBGR), standard deviation) used for the relative shift calculation. Additionally, the PSR did not specify the Type II error but stated that the Type II error rate and subsequent power achieved were dependent on the number of samples collected and the concentration variability in the sample set.
Provide the relative shift and Type II error calculations for each survey unit to enable NRC staff to verify the licensee collected the appropriate number of samples during the FSS. Identify data used to determine the standard deviation.
Observations: ADP used the standard MARSSIM method for calculating the required number of samples in the survey units.
Action: The item will be closed when ADP adequately revises the application to include the relative shift calculation and identify the data used to calculate the standard deviation for the relative shift equation in the FSSRs for the Class 3 areas.
8.i Information in the PSR included the average background for the R16Y and SEAL, and the collective background for all non-impacted areas. However, the method used to determine this background was not included.
Describe the approach for establishing background levels.
Observations: ADP explained that background in each survey unit was determined by averaging measurements taken at each corner and in the center of the survey unit.
Action: The item will be closed when ADP adequately revises the application to include the background determination method in the Class 3 area FSSRs.
8.ii Guidance recommends survey results be included as a part of the FSSR to support the overall release survey. The R16Y and SEAL FSSRs did not include scanning survey results (e.g., scan area designation, minimum and maximum scan reading, action level, whether investigative samples or scan alarms occurred). Provide a summary of the scan survey results for R16Y and SEAL survey units.
Understanding: ADP plans to include scanning survey maps for the survey units in the FSSRs summarizing the scanning survey results.
Action: The item will be closed when ADP adequately revises the application to summarize the FSSRs scanning survey results.
CR3 Partial Site Release Audit Topics Summary May 12-29, 2025 Page 8 of 16 No.
Discussion Topic NRC Staff Observations &
Closure Actions 8.iii The alarm set point and investigation level were set at the observed background plus the Minimum Detectable Count Rate (MDCR) for the areas being scanned. For areas exceeding these values, an investigation was conducted to bound the elevated area, and additional samples were collected where elevated measurements were verified. Although the background was provided in the PSR, the MDCR or the input information to derive the MDCR was not included. Identify the variables other than background assumed in the MDCR calculation.
Observations: ADP noted that the MDCRs are routinely documented in the survey package.
Action: The item will be closed when ADP adequately revises the application to include the MDCR calculation.
8.iv The PSR described the investigative process as occurring following any alarms with investigative samples taken when elevated measurements were verified. Judgmental sampling was conducted in low lying areas and other areas where residual radioactivity may concentrate. In addition, the judgmental sampling occurred during scanning where measurements exhibited elevated radiation levels distinguishable from background. Clarify the difference between investigative and judgmental samples.
Understanding: ADP explained that investigative samples were obtained at the discretion of the technician when they encountered a hot spot.
Judgmental samples were taken in places where contamination may concentrate such as low-lying areas. They noted that the terms judgmental and biased are used interchangeably throughout the PSR.
Action: The item will be closed when ADP adequately revises the application to clarify the difference between investigative and judgmental sampling in the FSSRs.
9.i.a Dredged sediment from the CR3 East and West Settling Ponds was deposited somewhere in the CASA, however, the location within the pile is unknown. Provide any historical information on the volume of sediment and the location where the sediment was deposited within the coal ash.
Understanding: New information was obtained about the radioactive material deposited in the CASA. Sampling from December 13, 2011, indicates that the dredging contained no plant derived activity above background levels.
Furthermore, the coal ash heavy metal in ground water remediation effort resulted in the removal of the coal ash material from the CASA in 2016 or 2017, which is believed to include the Settling Pond dredge. The licensee proposes downgrading the status of the CASA from a MARSSIM Class 3 area to a non-impacted area with the new information.
The new information is documented in a new report placed in the online portal.
Action: NRC staff will evaluate the assumption that no radioactive material was sent to the CASA upon receipt of the BRA data to determine if the CASA can be reclassified as non-impacted.
CR3 Partial Site Release Audit Topics Summary May 12-29, 2025 Page 9 of 16 No.
Discussion Topic NRC Staff Observations &
Closure Actions 9.i.b On September 2, 2009, the State of Florida Department of Health Bureau of Radiation Control (DOH) collected and analyzed sediment from the Settling Ponds, which is summarized in Attachment A, WOCZ Settling Pond Position Paper. Eight samples were collected along the banks of each pond. However, there were no sediment samples collected in the center of the ponds.
Explain how the September 2009 samples on the banks of the East and West Settling Ponds are representative of the residual radioactivity concentration throughout the ponds.
Understanding: ADP proposed changing the classification of the CASA to non-impacted based on information in a report placed in the online portal.
ADP provided data collected by the state of Florida from the Settling Ponds as documented in the Radiological Environmental Monitoring Program (REMP) reports. The report identified four samples taken at the interface between the bank and the bottom of the East Settling Pond which were representative of the center of the pond.
Action: Item is closed because the four samples, in conjunction with those samples collected on the banks by the state of Florida, provide a representative sampling of the East Settling Pond.
9.ii On December 13, 2011, four samples were collected with a maximum concentration of 0.02716 pCi/g Cs-137. No additional information on this sampling campaign was provided. Describe the sampling locations and method for the four December 2011 samples collected from the East and West Settling Ponds.
Understanding: ADP proposed changing the classification of the CASA to non-impacted based on information in a report placed in the online portal.
See item 9.i. The report discussed this sampling effort and provided the analytical results. ADP plans to update the report to remove the reference to the REMP Cs-137 background concentration as this background is limited to specific areas of the site.
Action: NRC staff will use the indistinguishable from background concentration derived from the new BRAs to determine whether these four samples are at background and to evaluate the reclassification of the CASA as non-impacted.
9.iii The historical site assessment recommended additional surveys be performed below the ash pile to determine if residual radioactivity was present; however, this could not be performed without destroying the geosynthetic environmental barrier. To evaluate potential subsurface contamination, Attachment 4, Section 4.2 of the PSR stated that subsurface composite samples were collected for depths 0-3 feet (ft), 3-6 ft, and 6-9 ft at each of fifteen locations. No specific information about the method for collecting subsurface sampling, other than compositing, was discussed.
Describe the sample collection method for subsurface sampling and justify the selection of a maximum sampling depth of 9 ft.
Understanding: ADP has proposed changing the classification of the CASA to a non-impacted area based on information in a report placed in the online portal. There is no requirement for subsurface sampling in a non-impacted area, which resolves this issue once the Settling Pond dredge is verified to be less than background.
Action: NRC staff will use the indistinguishable from background concentration derived from the BRAs to evaluate the reclassification of the CASA as non-impacted, which would not require subsurface sampling.
CR3 Partial Site Release Audit Topics Summary May 12-29, 2025 Page 10 of 16 No.
Discussion Topic NRC Staff Observations &
Closure Actions 9.iv For the CASA, in the absence of scanning surveys due to the presence of NORM, the licensee was dependent on sampling for identifying areas of elevated activity or anomalies, which consisted of fifteen survey locations where surface samples were collected. An integrated survey design combines scanning surveys with direct measurements and sampling, with the level of effort commensurate with the potential for residual radioactivity. MARSSIM recommends that judgmental scans be conducted in Class 3 survey units with a focus on areas with the highest potential for residual radioactivity. Identify a methodology to address the absence of scanning in the CASA.
Understanding: ADP has proposed changing the classification of the CASA to a non-impacted area based on information in a report placed in the online portal. See item 9.i. No scanning surveys are required for non-impacted areas which resolves this issue once the Settling Pond dredge is verified to be less than background.
Action: NRC staff will use the indistinguishable from background concentration derived from the BRAs to evaluate the reclassification of the CASA as non-impacted, where scanning would not be required.
10.i In a response dated March 21, 2025, CR3 explained the definitions of the terms Lower Limit of Detection (LLD), Minimum Detectable Activity (MDA), Minimum Detectable Concentration (MDC), MDL and Critical Limit (Lc). They stated that the use of detection terms in the PSR reflect the terms used on the onsite and offsite analytical reports. The licensee indicated that the terms LLD, MDA, MDC, and MDL were used interchangeably per the guidance in MARLAP. In a follow up response dated March 31, 2025, CR3 specified the equations used to calculate the LLD, MDA, MDC, MDL, and Lc and provided the reference for these equations. Clarify whether the LLDs for both water and soil are calculated using the formula from the ODCM.
Understanding: ADP explained the LLD was established as a performance criterion to be evaluated on an annual basis. The LLD equation in the ODCM is used to calculate an a priori value.
The same equation is used to determine an a posteriori sample MDC.
Action: ADP will revise their previous response to clarify that the LLDs for both water and soil were calculated using the LLD formula in the ODCM.
CR3 Partial Site Release Audit Topics Summary May 12-29, 2025 Page 11 of 16 No.
Discussion Topic NRC Staff Observations &
Closure Actions 10.ii.a Table 2-26 of the LTP, Rev. 2 summarized the sample results and their respective critical levels (Lc). Staff interpret the Lc in this table to be a posteriori. The March 31 response related the Lc to the LLD indicating the Lc is the lower bound of the 95%
detection interval defined for the LLD.
Clarify whether the Lc in Table 2-26 was calculated using the Stapleton Approximation (Sc) for alpha emitting radionuclides (Equation 20.54 of MARLAP) and the Currie method for gamma spectroscopy (Equation 20.48 of MARLAP) as discussed in the March 31 response.
Clarify the method used to calculate the Lc for beta emitters.
ADP explained the usage of the terms in their March 31 response provided in the online portal.
Further discussions are described below for clarifying the March 31 response.
Understanding: With respect to the MARSSIM approach, the actual sample results for the laboratory should be reported in the data tables whether positive, negative, and zero. These results can then be used to determine the basic statistical quantities such as the minimum, maximum, median, mean, and standard deviation. Actual results can also be used for the Wilcoxon Rank Sum test. For the LTP dose compliance determinations, if the median for a radionuclide determined from the basic statistical quantities is negative, the value should be set to zero for the sum of fractions calculation and the subsequent survey unit dose.
With respect to groundwater data, any values greater than the Lc are considered positive detections and thus contribute to a dose estimation.
The values less than the Lc are assumed to be zero (and thus a dose of zero). For dose estimation purposes, if the analytical result is between the Lc and MDC (a posteriori), the result should not be set to zero. If results are reported as <MDC, then the MDC should be used for a dose estimate. If actual result values are reported, then those results or MDC value can be used for dose estimates.
Action: The item will be closed when ADP adequately revises the application to include the discussion above.
CR3 Partial Site Release Audit Topics Summary May 12-29, 2025 Page 12 of 16 No.
Discussion Topic NRC Staff Observations &
Closure Actions 10.ii.b Table 3-2 of Attachments 2, 3, 4, and 5 list the ROCs and off-site laboratory GEL average MDLs. These appear to be a priori detection capabilities for GEL laboratory methods, which would be consistent with the MARLAP. MDL is defined in Environmental Protection Agency regulations as a method capability for hazardous contaminants (40 CFR Part 136 Appendix B). Table 1-1 of 1 also lists GEL laboratory MDLs. Clarify whether the MDL is an a priori method detection limit. Provide an example within the PSR GEL laboratory report where MDL is equated to MDA or MDC.
Action: The item will be closed when ADP adequately revises the application to eliminate the use of the term MDL and to replace it with MDC in the Phase II PSR.
10.ii.c Laboratory reports for onsite analyses provided a posteriori MDAs for each characterization and FSS sample listed in the results summary tables. Similarly, these same identified MDAs for GEL Laboratory results, which were taken from the MDCs (not MDAs) reported on the GEL laboratory reports. Furthermore, statements such as no plant-derived radioisotopes were detected above the MDC occur throughout Attachments 2, 3, 4, 5, and 10, which indicates a comparison to an a posteriori MDC. Based on the 3/31/25 response, the MDC equates to the MDA multiplied by the appropriate conversion factor to obtain a concentration. Staff understand this statement to mean the MDA represents results in terms of activity (e.g., pCi, uCi) versus MDC in terms of activity/unit (e.g.,
pCi/g, µCi/g). Clarify whether the MDC data from the GEL laboratory reports were listed in the sample results tables as the MDA.
Understanding: ADP stated that they are replacing the term MDA with MDC.
Action: The item will be closed when ADP adequately revises the application to eliminate the term MDA and to replace it with MDC in the Phase II PSR.
10.iii The sample count time can impact the MDAs for radionuclide concentrations in individual samples. Confirm the count time used for Phase I PSR reference area samples and Phase II PSR survey unit samples were identical.
Understanding: ADP identified the sample count time for survey unit samples as 1,000 seconds.
However, the Phase I PSR BRA data will not be used in the Phase II PSR indistinguishable from background analysis.
Action: Item to be closed because the question is no longer relevant.
CR3 Partial Site Release Audit Topics Summary May 12-29, 2025 Page 13 of 16 No.
Discussion Topic NRC Staff Observations &
Closure Actions 11.i MARSSIM, Section 9.3, Data Assessment recommends that data validation and verification be conducted to ensure the quality of the data and to ensure the results of the data collection activities meet the objectives of the survey. The staff was unable to reproduce the mean, median, and standard deviations found in Table 6-9, Basic Statistical Quantities for NIA-05. This information is important to support data to demonstrate the survey unit is indistinguishable from background.
Demonstrate to staff how the statistical quantities for NIA-05 were determined.
Understanding: ADP provided a written response to 11i stating that there were a few anomalies during data analysis that resulted in reanalysis of some samples. ADP will update data and statistical quantities table in Attachment 2 of the PSR to reflect the appropriate results.
Action: The item will be closed when ADP updates the data and statistical quantities tables for NIA-05 in PSR to reflect this change.
11.ii The statistical evaluations for survey units R16Y, SEAL, NIA-03, NIA-04, and NIA-05 included biased and investigative sample results in the statistical analysis. MARSSIM indicates that judgmental samples are not to be included in the survey unit data statistical evaluation as their use violates the assumption of randomly selected, independent measurements. Provide an updated statistical analysis excluding biased or investigative samples.
Understanding: ADP provided a written response to 11.ii stating that they plan to use random samples for statistical analysis and to exclude investigative and judgmental samples.
Action: The item will be closed when ADP updates the statistical quantities tables for survey units R16Y, SEAL, NIA-03, NIA-04 and NIA-05 in PSR to reflect this change.
11.iii The Executive Summary (ES) for and Attachment 11 of the PSR included a summary of data from the non-impacted areas listing the analytical results by survey unit that exceeded the MDA.
There are inconsistencies between the two ESs for NIA-01, NIA-02, NIA-03, and NIA-06 relating to the number of samples above MDA and the sample results in some cases.
Explain the discrepancies in the ES sample results between Attachment 2 and 1 of the PSR, identifying any additional data not included in Attachments 2 that are not in Attachment 11 and vice versa.
Understanding: ADP provided a written response to 11.iii acknowledging the discrepancies between and 11 summaries.
Action: The item will be closed when ADP updates 1 of the PSR to reflect the results of reanalyzed samples.
CR3 Partial Site Release Audit Topics Summary May 12-29, 2025 Page 14 of 16 No.
Discussion Topic NRC Staff Observations &
Closure Actions 12.i There are several miscellaneous errors that occurred throughout the PSR that need to be corrected. MARSSIM, Section 3.0, "Historical Site Assessment" recommends the HSA delineate between impacted and non-impacted areas. Attachment 1 stated, The HSA identified areas outside of the Protected Area as non-impacted because they were not specifically identified in the HSA. The Protected Area fence was defined in Figure 9, Crystal River Unit 3 Preliminary Classifications of Non-Radiological Impacts in the Vicinity of Storage Tanks and Transformers of. There are several impacted survey units, including the CASA, SEAL, and R16Y outside the Protected Area fence.
Explain the conclusion that areas outside the Protected Area are non-impacted.
Action: ADP will revise this comment in the PSR to reflect the fact that there are impacted areas outside the Protected Area.
12.ii.a Attachment A, WOCZ Settling Pond Dredge Position Paper, in Attachment 10 of the PSR describes the process for determining a bounding external dose from exposure to Settling Pond sediment. The final paragraph of the white paper stated the highest concentrations in the sediment for Cs-137 and Co-60 were 2.99E-1 Ci/g and 2.7E-2 Ci/g, respectively, whereas the data table (page 4 of 7) listed the values as 299 pCi/kg for Cs-137 and 27 pCi/kg for Co-60. There is an inconsistency in radionuclide concentrations between the data table and the final paragraph of Attachment A.
Resolve the error.
Understanding: ADP provided the "History of the Settling Pond Radioactivity Levels and Work Activities," which is a replacement to the "WOCZ Settling Pond Dredge Position Paper." The revised document does not include a bounding dose calculation.
Action: Item is closed because the issue of inconsistent radionuclide concentrations is resolved.
12.ii.b The Attachment A dose calculation was based on MARSSIM (pg. 6-45), which indicated a Cs-137 soil concentration of 5 pCi/g was equated to 1.307 R/hr. Rather than using 5 pCi/g, the dose calculation assumed 5,000 pCi/g, which was inconsistent with MARSSIM. While the dose of 0.15 mrem appears to be correct, the errors lead to a lack of confidence in other calculations. Correct the error.
Understanding: ADP provided the "History of the Settling Pond Radioactivity Levels and Work Activities" which is a replacement to the "WOCZ Settling Pond Dredge Position Paper." The revised document does not include a bounding dose calculation.
Action: Item is closed because the History of the Settling Pond Radioactivity Levels and Work Activities does not include a bounding dose calculation.
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Discussion Topic NRC Staff Observations &
Closure Actions 12.iii Attachment A, Table 1 of Attachment 4:
Characterization survey sample locations are identical to the first nine FSS coordinates. In addition, Table 1 coordinates are inconsistent with Table B-1, Coal Ash Storage Area (CASA) Sample Locations in Attachment 10 of the PSR.
Reconcile the Attachment 4 and 10 characterization survey sample locations for the CASA.
Understanding: ADP will update the Attachment A, Table 1 in Attachment 4, to reflect the correct sample coordinates for the characterization samples.
Action: The item will be closed when ADP adequately revises the application to reflect the correct characterization sample coordinates.
12.iv Table 3 of Attachment 1 of PSR averages may not be correct.
Understanding: Discussions identified the differences between NRC staffs method of calculating the average and ADPs method. ADPs method involved setting negative values to zero and including the zeroes to calculate the average.
Action: Item will be closed because the NRC understands how the average value is calculated.
13.i Section 6.3.1, "Non-Impacted Areas" of the HSA states there are many buildings, structures, and areas located within the site footprint outside the Protected Area that are not likely to have been impacted by site operations. A meeting conducted with licensee staff discussed the approach to dispositioning these buildings, structures, and areas. The meeting was documented in "HSA Licensed Footprint Meeting Minutes (25Feb2016).pdf." Provide a copy of this document for review.
Understanding: ADP will provide the document "HSA Licensed Footprint Meeting Minutes" dated 25 Feb 2016 for review by NRC staff.
Action: Item will be closed because ADP provided the document for NRC staff review.
13.ii According to Attachments 2, 3, 4, and 5 of the PSR, the QA/QC checks and controls, calibrations, and training were conducted in accordance with the Quality Assurance Project Plan, NS-FSS-19. This document also serves as an input to the third step of the DQO process. Provide a copy of this document for review.
Understanding: ADP will provide the document NS-FSS-19, "Quality Assurance Program Plan" for review by NRC staff.
Action: Item will be closed because the NRC reviewed the document NS-FSS-19, "Quality Assurance Program Plan."
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Discussion Topic NRC Staff Observations &
Closure Actions 13.iii The potential radionuclides of concern at the CR3, according to the PSR, have been established in the CR3 Technical Basis Document (TBD), Crystal River Unit 3 Radiological Nuclides of Concern for DCGL Development (NorthStar, 2024). ADP appears to be defining the thirteen radionuclides selected for offsite analysis based on the thirteen dose significant radionuclides listed in this TBD. The document is currently a part of the LTP, Rev.
2 (Appendix A to Chapter 6 of the LTP Rev 2). Clarify whether this is the basis ROCs established for offsite analysis.
Understanding: ADP will provide the document Crystal River Unit 3 Radiological Nuclides of Concern for DCGL Development, Rev. 4 for review by NRC staff.
Action: Item will be closed because the NRC reviewed the document Crystal River Unit 3 Radiological Nuclides of Concern for DCGL Development, Rev. 4, which established the thirteen radionuclides identified for offsite analysis.
13.iv Table 5-6, Other Building Substructures DCGLs, ROCs, Normalized Fractions, and TEDE Evaluation, of the LTP Rev. 2 establishes the dose significant radionuclides for other buildings and open land areas based on characterization data.
Based on information provided in this table, all radionuclides other than Cs-137 are insignificant contributors. Thus, only Cs-137 must be considered in the FSS detailed analysis. Provide Table 5-6, or an updated version, to support the deselection process or justify the assumption that Cs-137 is the only significant contributor.
Understanding: ADP will provide the information justifying the choice of Cs-137 as the only radionuclide requiring detailed analysis for review by NRC staff.
Action: Item will be closed because the NRC reviewed the document TSD -Establishing Testing Requirements for Soil Background at CR3, which established Cs-137 as the only dose significant contributor.
13.v Results of December 2023 groundwater sampling event for all 13 radionuclides in the initial suite presented in Table 2-26 in LTP Rev. 2.
Action: Item is closed because ADP provided results from Table 2-26 in the TSD provided for item 2.i which ADP indicated will be attached to the revised Phase II PSR application.
13.vi GHS (2017) CR3 Groundwater Flow Study Summary Report; provided in Enclosure 15 to LTP Rev 2, also provided in Enclosure 22 to LTP Rev. 1.
Understanding: ADP will provide for review by NRC staff if needed. The need is dependent on items 1.i and 1.ii.
Action: This item will be closed because information on water quality and use (item 1.i and 1.ii) is no longer needed due to resolution of item 2.i (radionuclide data in Table 2-26 of LTP Rev 2 are likely false positives). GHS (2017) does not need to be provided for the Phase II PSR.