ML26027A171
| ML26027A171 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 03/14/2024 |
| From: | Davis L Energy Solutions, Omaha Public Power District |
| To: | Division of Decommissioning, Uranium Recovery and Waste Programs |
| Shared Package | |
| ML26027A165 | List: |
| References | |
| EPID L-2025-LLN-0012 FC-24-004, Rev 1 | |
| Download: ML26027A171 (0) | |
Text
Page 1 of 40 FC-24-004 Revision 1 DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches Prepared By:
LJ Davis Date Reviewed By:
John Clements Date Approved By:
Date 3-14-24 3-14-24 03/15/2024 Jason Q. Spaide Digitally signed by Jason Q.
Spaide Date: 2024.03.15 06:01:19 -05'00'
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 2 of 40 1.0 PURPOSE The purpose of this Technical Support Document (TSD) is to provide a summary of the DCGLs, remediation strategy and survey methodology for the Auxiliary Building (AB)
A discussion of these trenches and their end state are provided below. The relevant portions of this TSD will be incorporated into Revision 2 of the FCS License Termination Plan (LTP).
2.0 DISCUSSION 2.1 Overview The AB structure will be removed to a minimum of three feet below grade (approximately 1,001 feet Above Mean Sea Level (AMSL)). All of the interior walls in the AB basement have been removed. Once Demolition and Decommissioning (D&D) activities and Final Status Surveys (FSS) are complete, the basement will be backfilled to grade level (approximately 1,004 feet AMSL).
The East Trenches survey unit consists of 30 trenches, with a total surface area of approximately 860 m2. Two of the trenches were installed during plant construction (Trenches 15 and 25). The remainder of the trenches were East Trench survey unit is classified as MARSSIM Class 1. The floors and to a lesser extent, the walls of these trenches are contaminated.
The current plan includes backfilling the trenches with grout or concrete as a mitigation measure. The term grout in this report will be used to refer to the material used to backfill the trenches. This could be grout or concrete with additives to improve the long-term performance of the material as an engineered barrier.
The remediation of the Auxiliary Building floors and walls started in July of 2023 and is currently ongoing. In order to proceed into Open Air Demolition (OAD) of the Auxiliary Building the floor drains were mechanically plugged and grouted to protect them during OAD. Once the floor drains were accessible, the majority of were removed. However, the drains that were too close to the bottom of the foundation or that required an excessive level of effort (i.e.,
drains below or in the vicinity of the Spent Fuel Pool pad) were not removed. The drain piping was removed by saw cutting along the length of the piping and then demolished utilizing an excavator with a pneumatic hammer attachment.
The East Trenches have been remediated to the maximum extent possible. The concrete foundation has been damaged by the trench remediation and further remediation is expected to increase the damage. This damage has resulted in foundation fractures that allow groundwater intrusion. It could also create pathways for migration of contamination into previously uncontaminated areas of
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 3 of 40 concrete. The further intrusion of groundwater could result in the migration of contamination within the basement.
In September of 2023, a contractor installed grout beneath the structure to mitigate groundwater intrusion. The contractor drilled holes along the edges of trenches and installed ports to inject polyacrylate as intercept grouting.
Polyacrylate grout was also injected into cracks. After the sealing of the cracks, the contractor performed soil grouting to reduce groundwater in-leakage. Soil grouting consisted of drilling holes through the bottom of the trench slabs and injecting acrylamide grout. Injection ports and the openings for crack sealing and soil grouting were repaired and covered with cementitious repair mortar.
The groundwater in-leakage issue is exacerbated by the fact that the U.S. Army Corps of Engineers plans to release water for navigation flow support into the Missouri River. The commercial navigation season is normally from late March to early December. Specific minimum flow rates are required during the navigation season to provide adequate depths and width. During insufficient natural flows, water is released from the upstream reservoir system. The current projection is that the ACE will begin to release water in mid-March, 2024.
Groundwater in-leakage can be eliminated by grouting the trenches before the rising river levels increase the groundwater levels. However, FSS must be completed prior to the grouting of the trenches. To expedite the remediation and FSS of the trenches a decision was made to take credit for the grout as a mitigation measure in the dose calculations.
Revised Derived Concentration Guideline Levels (DCGLs) have been calculated for the trenches. These account for the use of grout and to modify some of the more conservative assumptions in the original DCGLs. Additionally, provision has been made for the use of Areas Factors to decrease the amount of remediation necessary and facilitate meeting the deadline for grouting.
Once the basement is backfilled there is a concern that radioactive contamination migrating through the grout, may reach the surface of the grout, where it will then enter the groundwater. To determine the extent of this migration, modelling was performed to calculate the diffusion factors for all radionuclides of interest. To minimize the migration, the trenches will also be covered with an additional layer of grout to prevent the release of radionuclides to the groundwater above the grout. The results of the modelling and calculations are contained in TSD FC Diffusion Factors of Radionuclide Release Through Grouted Trenches (Ref. 8.7). The results of the diffusion factor calculations were used to calculate DCGLs for the grouted East Trenches.
Continuing characterization was performed in February, 2024 to support the development of radionuclide mixture fractions and surrogate ratios for the East Trenches. Concrete core samples were collected from the surfaces of the
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 4 of 40 trenches and sent to an off-site laboratory for analysis. The results were evaluated using the same calculational methodologies that were employed in TSD 21-043 Radionuclides of Concern in Support of the Fort Calhoun License Termination Plan (Ref. 8.4). The results were used to establish a mixture fraction, Radionuclides of Concern (ROCs) and Insignificant Contributors (IC) to dose.
The resulting activity fractions and ROCs were used to establish surrogate ratios.
The IC Dose Adjusted Base Case, and surrogate ratios were then used to establish effective Base Case DCGLs for gamma emitting nuclides. Operational DCGLs (OpDCGLs) were calculated for determining compliance. The effective Base Case DCGLs were used to determine the required survey detection limits.
A Remedial Action Support Survey (RASS) was performed at the end of February, 2024 and the results revealed that there were no areas that would require further remediation.
FSS will be performed to demonstrate that the concentrations of residual activity are equal to or below Derived Concentration Guide Limits (DCGLs) corresponding to the dose criterion in 10 CFR 20.1402. The residual radioactivity must also be reduced to levels that are As Low As Reasonably Achievable (ALARA).
Once the FSS and NRC confirmatory surveys are complete, the trenches will be backfilled with grout to floor level. Upon completion of remediation in the remainder of the basement, the remaining basement surfaces will undergo FSS.
Upon the completion of FSS and prior to backfill, an additional layer of grout will be added to the tops of the trenches.
2.2 Details of the East Trenches The methods used for demolition of the trenches resulted in large variations in their dimensions and configurations. The dimensions of the trenches are included in Table 1 below. The wall, floor and total surface areas for each trench are also shown.
basement.
Table 1: Trench Dimensions and Surface Areas Trench Length (m)
Width (m)
Depth (m)
Floor Area (m2)
Wall Area (m2)
Total Area (m2)
Additional Irregular Surface Area (m2)
Total Surface Area (m2) 1 7.9 1.0 0.4 7.9 6.3 14.2 14.2 2
4.5 1.0 0.4 4.5 3.2 7.7 7.7
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 5 of 40 Trench Length (m)
Width (m)
Depth (m)
Floor Area (m2)
Wall Area (m2)
Total Area (m2)
Additional Irregular Surface Area (m2)
Total Surface Area (m2) 3 4.7 1.0 0.5 4.8 4.7 9.5 9.5 4
4.7 1.3 0.5 5.9 5.1 11.0 11.0 5
2.4 1.0 0.5 2.4 2.4 4.8 4.8 6
10.2 1.1 0.7 10.7 14.7 25.4 25.4 7
4.7 1.1 0.9 5.1 8.2 13.3 13.3 8
2.1 0.9 0.6 1.9 2.5 4.4 4.4 9
18.0 1.1 1.2 19.8 41.8 61.6 61.6 10 4.0 1.2 1.0 5.0 7.8 12.7 12.7 11 6.5 1.0 0.8 6.5 9.8 16.4 16.4 12 2.8 1.7 0.6 4.6 3.1 7.7 6.6 11.2 13 3.2 0.9 0.7 2.9 4.6 7.5 7.5 14 7.0 2.0 1.1 13.7 15.2 28.9 28.9 15 18.7 1.0 0.6 18.5 22.4 41.0 41.0 16 18.7 1.5 1.1 27.4 39.9 67.3 67.3 17 2.3 2.0 0.8 4.7 3.7 8.4 1.8 10.1 18 40.4 1.2 0.9 47.2 71.1 118.3 6.0 124.3 19 3.7 1.0 1.3 3.7 9.3 13.0 13.0 20 5.7 1.8 1.1 10.0 12.5 22.5 22.5 21 2.6 0.9 0.7 2.2 3.6 5.9 5.9 22 9.3 1.2 0.6 10.7 11.1 21.8 51.0 23 17.9 1.4 1.0 24.2 35.2 59.4 59.4 24 3.4 1.0 0.9 3.4 6.1 9.5 9.5 25 1.0 0.8 0.7 0.8 1.4 2.2 2.2 26 9.6 0.9 0.7 8.4 13.7 22.0 36.0 26A 3.1 2.8 0.7 8.4 4.1 12.5 12.5 27 7.5 1.4 1.2 10.4 17.9 28.3 2.3 30.6 28 11.4 1.2 0.7 13.1 16.0 29.1 29.1 28A 0.0 0.0 0.0 4.9 4.9 29 27.9 1.1 0.8 30.6 44.6 75.2 75.2 30 13.8 1.0 0.5 13.8 14.4 28.2 6.4 34.6 Total Surface Area:
333.3 456.2 789.5 27.9 857.44
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 6 of 40 3.0 USE OF GROUT AS AN ENGINEERED BARRIER Grouting results in a reduction in radionuclide releases. A reduction in radionuclide release is linearly correlated to a reduction in dose. The crediting of grout for contamination retention is a standard industry practice that has received regulatory approval at other decommissioning sites. Three such sites were Connecticut Yankee (CY), Zion and Plum Brook.
The In-Core Sump area concrete in the CY Containment Building had elevated levels of H-3, Co-60, Fe-55, and Eu-152. An analysis was performed of the radionuclide release rates from the concrete. These were then used to determine the acceptable levels of residual activity that could remain at site closure. These acceptable levels would not result in releases to groundwater in excess of the acceptable dose limits. (Ref. 8.11)
At Zion the Auxiliary Building floor drains were decontaminated, surveyed and grouted. The Zion LTP (Ref. 8.12 applied DCGLs which assumed that activity was released from the drains at the same rate as from the basement floor or wall surfaces. The dose calculated using the DCGL values was highly conservative because it did not take credit for the reduction in release due to the presence of grout. Therefore, a more realistic, yet still reasonably conservative dose calculation was performed for the Auxiliary Floor Drains that accounted for the presence of grout. This was used in the final demonstration of compliance with the dose criterion.
The Plum Brook Reactor Facility (PBRF) contained a large amount of embedded piping. The embedded piping DCGL values represented surface activity concentrations that corresponded to an annual dose of 1 mrem/yr to a future building occupant. The only exposure pathway that was considered for embedded piping was direct dose from gamma-emitting radionuclides. In order to utilize the DCGL values, the piping was required to be grouted prior to license termination. All the radionuclides present in piping residual contamination were assumed to be fixed in place by grout and were considered as not available for transport to ground water or to ingestion or inhalation pathways to a future building occupant (Ref. 8.13).
To support the use of grout in the trenches at FCS, modelling and calculations were performed to determine the diffusion factors for the radionuclides of interest. Estimates of the fractional release of contaminants from the grout/concrete are required to verify that the DCGL values are conservative. The fractional releases have been calculated for all of the radionuclides listed in Table 5-2 of the License Termination Plan (Ref. 8.1).
To minimize the potential for radionuclide migration, the trenches will be covered with clean grout with a thickness of 15 to 45 cm. The trenches range in depth from 1.5 to 5 feet. The median depth is 2.79 feet, and the mean depth is 3 feet.
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 7 of 40 To examine the potential release from this pathway into the groundwater, the maximum release from this condition will be simulated by placing the entire inventory of the existing cement at the interface with the grout in the trench (initially uncontaminated zone) and simulating the diffusion up to the edge of the trench (i.e., no additional cover), Two cases are simulated, 45 cm (~1.5 feet, the minimum initial grout thickness) and 90 cm (mean depth of the trenches.
Initial characterization indicates there is some residual contamination in the walls.
However, most of the contamination is at the bottom surface of the trench. To accommodate the possibility of wall contamination, it is assumed that the contamination along the walls causes the grout/concrete to be uniformly contaminated. This is a conservative assumption based on the initial characterization data. The contamination will be covered by clean grout and three cover thicknesses are simulated,1 5, 30, and 45 cm.
4.0 ALARA CONSIDERATIONS NUREG-1757 Vol. 2 (8.2) provides guidance to licensees considering the use of engineered barriers such as stabilizing cementitious materials to demonstrate compliance with radiological criteria for license termination. Engineered barriers are passive, man-ability to meet the dose criteria in the License Termination Rule (LTR).
Engineered barriers are usually designed to inhibit water from contacting waste and releasing radionuclides to groundwater, thereby reducing exposure from ingestion of contaminated water.
NUREG 1757 states that for licensees pursuing unrestricted use of their site, residual radioactivity must be reduced to levels that are ALARA before reliance on engineered barriers to meet LTR criteria. The use of grout as proposed in this TSD would be considered an engineered barrier. Therefore, the residual radioactivity in the trenches will be reduced to levels that are ALARA without factoring in the reduction in releases due to grouting.
5.0 DERIVED CONCENTRATION GUIDELINES (DCGLS)
Several revisions were made to the Basement Fill Model (BFM) to reduce conservatism in the DCGL calculation for the trenches in the Auxiliary Building basement floor. These changes will be described in detail in LTP Chapter 6, Revision 2. The revised Base Case, IC Dose Corrected and Operational DCGLs are provided in Table 2 below.
The DCGL values have been adjusted in this calculation to include the Insignificant Contributor doses. In accordance with NUREG-1757, Volume 2, Revision 1, Section 3.3 (Ref. 14.15) radionuclides that contribute, in aggregate,
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 8 of 40 Insignificant Contributor (IC) radionuclides may be eliminated from further consideration in FSS and from detailed dose modeling but the aggregate dose from the insignificant contributors must be accounted for in demonstrating compliance. The IC dose determined in Section 6.4 below was 4.8%.
To ensure that the summation of dose from each source term, or media, is 25 mrem/year or less after all FSS is completed, the DCGLs are reduced based on a projected, or a priori, fraction of the 25 mrem/year dose limit from each media.
The a priori fraction is based on the results of site characterization, process knowledge, and the extent of planned remediation. The a priori fraction for the Auxiliary Building is 0.15. These reduced Adjusted DCGLs are referred to as Operational DCGLs (OpDCGLs).
The descriptions and justifications for the changes to the Basement Fill Model are provided in Table 3.
Table 2: Revised DCGLs for Trenches in the Floor of The Auxiliary Building Basement Radionuclide Base Case DCGLs (pCi/m2)
IC Dose Corrected DCGLs (pCi/m2)
Operational DCGLs (pCi/m2)
Am-241 1.44E+10 1.37E+10 2.06E+09 C-14 1.80E+13 1.71E+13 2.57E+12 Ce-144 1.04E+10 9.91E+09 1.49E+09 Cm-243 3.41E+09 3.25E+09 4.87E+08 Cm-244 3.70E+10 3.52E+10 5.28E+09 Cm-243/244 3.41E+09 3.25E+09 4.87E+08 Co-58 1.39E+09 1.32E+09 1.98E+08 Co-60 1.48E+08 1.41E+08 2.11E+07 Cs-134 2.79E+08 2.66E+08 3.99E+07 Cs-137 6.66E+08 6.34E+08 9.51E+07 Eu-152 3.28E+08 3.13E+08 4.69E+07 Eu-154 3.04E+08 2.89E+08 4.34E+07 Eu-155 1.30E+10 1.23E+10 1.85E+09 Fe-55 1.48E+14 1.41E+14 2.11E+13 H-3 1.76E+09 1.68E+09 2.52E+08 Ni-59 2.87E+13 2.73E+13 4.10E+12 Ni-63 1.05E+13 9.99E+12 1.50E+12 Np-237 1.81E+09 1.72E+09 2.59E+08 Pu-238 2.30E+10 2.19E+10 3.29E+09 Pu-239 2.07E+10 1.97E+10 2.96E+09
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 9 of 40 Radionuclide Base Case DCGLs (pCi/m2)
IC Dose Corrected DCGLs (pCi/m2)
Operational DCGLs (pCi/m2)
Pu-240 2.08E+10 1.98E+10 2.96E+09 Pu-239/240 2.07E+10 1.97E+10 2.96E+09 Pu-241 1.03E+12 9.80E+11 1.47E+11 Sb-125 1.03E+09 9.82E+08 1.47E+08 Sr-90 6.71E+10 6.39E+10 9.58E+09 Tc-99 1.74E+11 1.66E+11 2.49E+10
Page 10 of 40 Table 3: Description and Justification for Revisions to the Auxiliary Building Basement Fill Model to Reduce Conservatism in the DCGLs Assigned to the Trenches Conceptual Change Model Change Justification 1 Changed assumption that excavated concrete acts like soil Evaluate two scenarios and select the lowest DCGL for each radionuclide. The scenarios are: 1) no cover no plants or fodder, no meat, no milk, and 2) 1 m cover with plants, meat and milk. Assign the lowest DCGL for the two scenarios Plants and fodder cannot be grown directly on concrete. A soil cover is required to grow plants and fodder. Soil cover depth is assumed to be 1m.
2 Resident Farmer Concrete Excavation Scenario applies to the upper two meters of wall only. This allows for three meters deep excavation below the ground surface.
Excavation below 2 m of wall not included in Resident Farmer BFM DCGL. But 1.25 mrem/yr (5% of 25 mrem/yr criterion) assigned to excavation of top 2 m of walls.
The first meter below the surface is clean fill.
Not plausible that resident farmer would perform large-scale excavation of deep walls and floors.
3 Resident Farmer scenario includes only the excavation of top 2 m of walls The minimum wall thickness assumed for excavation scenario is the same as in LTP Rev 1 Resident Farmer excavation limited to 3 m below ground surface to construct a basement for a residence.
4 Full excavation of walls and floors is assumed to occur in the LLBP Industrial Use scenario SA/V ratio for excavation includes all basement walls and floors. The SA/V ratio is used to calculate an effective wall thickness for the Industrial Use scenario using the methods described in Chapter 6 Revision 1.
Not plausible that resident farmer would conduct large-scale excavation of deep walls and floors. Large-scale excavation would occur for Industrial Use Scenario only 5 Changes to Resident Farmer Scenario Parameters for Industrial Use Scenario.
Cover 0.0 (m)
Inhalation rate 3.066E+03 (m3/yr)
Fraction of time indoors 1.875E-01 (unitless)
The Industrial Use parameters were the same as used in the La Crosse LTP which applied Industrial Use as the compliance scenario. The bases for the La
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 11 of 40 Fraction of time outdoors 6.250E-02 (unitless) drinking water 3.27E+02 (L/yr) plant, meat, milk contaminated fractions 0.0 (unitless)
Crosse Industrial Use parameters are assumed to apply at SONGS.
6 Resident Farmer BFM DCGLs for the lower walls and floors (below 2 m) do not include excavation. The excavation of upper walls (the first 2 m) is included in Resident Famer scenario for deep walls/floors as described in Change item #2. The Resident Farmer BFM DCGL for lower walls/floors assumes that the contribution from the excavation of upper walls is less than 1.25 mrem/yr (5% of 25 mrem/yr criterion)
Resident Farmer Scenario DCGL includes in situ and drilling spoils only multiplied by 0.95 to allocate 5% of dose criterion (1.25 mrem/yr) to excavation of upper walls Excavation of upper walls are included in Resident Farmer scenario, but contribution limited to 1.25 mrem/yr 7 Assumed trenches filled with grout and an additional 30 cm grout cover placed over filled trench. Release limited by diffusion through the grout.
Groundwater contribution from trenches (in situ scenario) reduced by the release fraction through grout. DCGL increased by dividing the in situ DCGL by the diffusion fraction.
Grout cover reduces release of contamination to groundwater.
8 For Industrial Use Soil DCGL, the total dose from each year was calculated using the Trench and Auxiliary wall/floor mixtures to determine which year resulted in the highest dose given the trench Radionuclide mixture Minimum Np-237 DCGL occurs after year 300. Calculated the total dose at year of minimum Np-237 DCGL and other years between 0 and 1000 using the trench and wall/floor radionuclide mixture fractions.
The maximum dose considering the DCGLs within each time and the Reduce conservatism that occurs when the minimum DCGLs are assigned regardless of when the minimum DCGL occurs. For example, the minimum Np-237 DCGL occurs at year 341.4 but the year zero DCGL is assigned
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 12 of 40 radionuclide mixtures occurs at year zero for both the trench and wall/floor mixtures.
The year zero DCGLs were assigned as the excavation scenario DCGLs.
because the total dose, considering all initial suite radionuclides at their respective mixture fractions, occurs at year zero.
Page 13 of 40 6.0 RADIONUCLIDES OF CONCERN AND RADONUCLIDE MIXTURE FRACTION 6.1 Radionuclides of Concern TSD 21-Radionuclides of Concern in Support of the Fort Calhoun License Termination Plan (Ref. 8.4) establishes the basis for an initial suite of potential ROC for decommissioning. Industry guidance was reviewed as well as the analytical results from the sampling of various media from past plant operations.
An initial suite of radionuclides was prepared after the elimination of some of the theoretical neutron activation products, noble gases, and radionuclides with a half-life less than two years (with the exception of Ce-144). The initial suite is listed in Table 5-2 of the LTP and is reproduced in Table 4 below.
Table 4: Initial Suite of Radionuclides Radionuclide Half Life (Years)
Radionuclide Half Life (Years)
Am-241 4.32E+02 Fe-55 2.74E+00 C-14 5.70E+03 H-3 1.23E+01 Ce-144 0.78E+00 Ni-59 1.01E+05 Cm-243 2.85E+01 Ni-63 1.00E+02 Cm-244 2.85E+01 Np-237 2.14E+06 Co-58 0.19E+00 Pu-238 8.77E+01 Co-60 5.27E+00 Pu-239 2.41E+04 Cs-134 2.06E+00 Pu-240 6.60E+03 Cs-137 3.02E+01 Pu-241 1.44E+01 Eu-152 1.35E+01 Sb-125 2.76E+01 Eu-154 8.80E+00 Sr-90 2.88E+01 Eu-155 4.76E+00 Tc-99 2.11E+05 6.2 Continuing Characterization Sample Results samples were collected from East Trenches using Continuing Characterization Plan 2002-C (Ref. 8.14).
The offsite analysis was performed by GEL Laboratories LLC in Charleston SC and the results are reported in (References 8.9 and 8.10). The seven samples with the highest concentrations of gamma-emitters were analyzed for the full suite of radionuclides in Table 4 above. The remaining eleven samples were analyzed for gamma emitters, C-14, Ni-63 and Sr-90.
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 14 of 40 GEL Laboratory Reports 653015 and 653354 contain the analytical results for the sample. The reports contain the sample activity, 2-sigma uncertainty, critical level (Lc) and Minimum Detectable Activity (MDA) for each of the radionuclides listed in Table 4 above. This laboratory report also contains the internal laboratory QA/QC analytical data, along with a case narrative.
Tables 5 through 7 provide the analytical results for the seven samples analyzed for the full suite of radionuclides. These results include all values as reported by GEL, regardless of whether or not they were less than any screening values such as the LC or MDA. Negative decay corrected results have been reset to zero to avoid generating fractional results greater than one. The reported concrete sample concentrations were decay corrected from the sample analysis dates to the anticipated license termination date of October 5, 2026.
It should be noted that due to alpha energy resolution limitations, the laboratory reports two radionuclide pairs: Pu-239/240, and Cm-243/244. Each of these pairs are considered a single reported nuclide in this analysis.
The decay corrected Am-241 concentrations include the in-growth of activity from the decay of Pu-241. Equation 1 represents how this was accounted for.
Equation 1
Page 15 of 40 Table 5: Sample Analytical Results, First Set of Radionuclides (pCi/g)
Sample ID H-3 C-14 Fe-55 Co-58 Ni-59 Co-60 Ni-63 Sr-90 2002X-1-CJ-FCV1-003 0.0-0.5T 3.24E+00 0.00E+00 0.00E+00 0.00E+00 1.01E-01 1.20E-02 5.03E-01 6.96E-02 2002X-1-CJ-FCV1-005 0.0-0.5 1.03E+01 8.25E+01 3.29E+00 1.31E-06 8.12E+00 2.95E+01 8.71E+02 8.69E+00 2002X-1-CJ-FCV1-006T 1.79E-01 3.94E+01 7.30E-01 2.38E-05 1.36E+00 3.02E+01 2.35E+02 1.57E+00 2002X-1-CJ-FCV1-007T 8.24E-01 9.20E+00 2.35E+00 0.00E+00 4.83E-01 1.08E+01 3.31E+01 4.65E-03 2002X-1-CJ-FCV1-010 0.0-0.5 1.32E+01 3.67E+02 1.44E+01 4.13E-05 3.63E+00 1.11E+02 5.91E+02 6.12E+00 2002X-1-CJ-WCV1-017 0.0-0.5T 3.43E+00 1.63E+00 2.39E-01 3.65E-06 0.00E+00 3.63E-01 0.00E+00 3.42E-02 2002X-1-CJ-WCV1-018 0.0-0.5T 3.20E-01 0.00E+00 0.00E+00 0.00E+00 0.00E+00 9.42E-02 7.22E-01 0.00E+00 Table 6: Sample Analytical Results, Second Set of Radionuclides (pCi/g)
Sample ID Tc-99 Sb-125 Cs-134 Cs-137 Ce-144 Eu-152 Eu-154 2002X-1-CJ-FCV1-003 0.0-0.5T 5.39E-01 0.00E+00 2.80E-02 3.99E-01 0.00E+00 7.82E-02 7.20E-02 2002X-1-CJ-FCV1-005 0.0-0.5 3.78E+01 0.00E+00 2.52E-01 2.35E+03 1.43E-01 3.77E-01 1.05E-01 2002X-1-CJ-FCV1-006T 3.20E+00 1.15E-01 4.60E-02 2.29E+02 2.44E-02 0.00E+00 2.37E-01 2002X-1-CJ-FCV1-007T 6.38E-01 1.39E-02 3.41E-02 2.69E+01 5.18E-03 2.72E-02 8.10E-02 2002X-1-CJ-FCV1-010 0.0-0.5 2.74E+01 7.09E-01 2.19E-01 1.98E+03 0.00E+00 9.24E-01 2.06E-01 2002X-1-CJ-WCV1-017 0.0-0.5T 9.61E-01 0.00E+00 1.20E-02 7.17E-01 9.82E-03 0.00E+00 5.94E-02 2002X-1-CJ-WCV1-018 0.0-0.5T 5.46E-01 0.00E+00 2.94E-02 9.69E-01 0.00E+00 0.00E+00 0.00E+00 Table 7: Sample Analytical Results, Third Set of Radionuclides (pCi/g)
Sample ID Eu-155 Np-237 Pu-238 Pu-239/240 Am-241 Pu-241 Cm-243/244 2002X-1-CJ-FCV1-003 0.0-0.5T 0.00E+00 5.12E-03 2.85E-02 3.87E-02 0.00E+00 0.00E+00 0.00E+00 2002X-1-CJ-FCV1-005 0.0-0.5 1.91E-01 0.00E+00 8.13E-02 0.00E+00 1.53E-02 1.21E+00 9.74E-02 2002X-1-CJ-FCV1-006T 1.16E-01 0.00E+00 1.12E-01 4.53E-02 5.07E-01 0.00E+00 0.00E+00 2002X-1-CJ-FCV1-007T 0.00E+00 4.15E-03 6.04E-02 0.00E+00 3.72E-03 5.81E-01 0.00E+00 2002X-1-CJ-FCV1-010 0.0-0.5 0.00E+00 1.71E-03 2.29E-01 5.97E-02 2.29E-02 2.01E+00 3.83E-01 2002X-1-CJ-WCV1-017 0.0-0.5T 0.00E+00 2.00E-03 2.87E-02 0.00E+00 5.64E-03 6.85E-01 3.40E-02 2002X-1-CJ-WCV1-018 0.0-0.5T 3.76E-02 0.00E+00 3.10E-02 0.00E+00 1.33E-03 0.00E+00 1.61E-02
Page 16 of 40 Table 8 shows the average decay corrected MDCs from all 7 samples analyzed by GEL for each radionuclide. This listing demonstrates that an effective average MDC was achieved by GEL for each analysis.
Table 8: Average Decay Corrected MDCs from GEL Analysis Results of Concrete Samples for Each Radionuclide Radionuclide Average MDC (pCi/g)
H-3 4.94E+00 C-14 8.10E+00 Fe-55 4.25E+00 Co-58 2.34E-05 Ni-59 2.40E+00 Ni-63 2.00E+00 Co-60 2.11E-01 Tc-99 1.60E+00 Sr-90 2.07E-01 Sb-125 9.59E-01 Cs-134 1.56E-01 Cs-137 4.18E-01 Ce-144 1.70E-01 Eu-152 1.34E+00 Eu-154 6.88E-01 Eu-155 6.04E-01 Pu-238 1.27E-01 Pu-239/240 1.95E-01 Pu-241 3.01E+00 Am-241 2.74E-01 Cm-243/244 3.80E-01 Np-237 9.68E-03 Table 9 displays the gamma emitting ROC results for all 18 samples. Table 10 converts the results to pCi/m2 and calculates the necessary statistical parameters for calculating the number of samples required in accordance with MARSSIM.
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 17 of 40 Table 9: Gamma Spectroscopy Results for ROCs of All 18 Samples Sample ID Co-60 (pCi/g)
Cs-137 (pCi/g) 2002X-1-CJ-FCV1-001 0.0-0.5T
-1.98E-02 1.95E-01 2002X-1-CJ-FCV1-002 0.0-0.5T 1.23E-01 4.64E-01 2002X-1-CJ-FCV1-003 0.0-0.5T 1.71E-02 4.24E-01 2002X-1-CJ-FCV1-004 0.0-0.5T
-3.88E-02 1.62E-02 2002X-1-CJ-FCV1-005 0.0-0.5T 4.19E+01 2.50E+03 2002X-1-CJ-FCV1-006 0.0-0.5T 4.29E+01 2.44E+02 2002X-1-CJ-FCV1-007 0.0-0.5T 1.53E+01 2.86E+01 2002X-1-CJ-FCV1-008 0.0-0.5T
-6.20E-02 0.00E+00 2002X-1-CJ-FCV1-009 0.0-0.5T 6.21E-02 1.17E-01 2002X-1-CJ-FCV1-010 0.0-0.5T 1.58E+02 2.11E+03 2002X-1-CJ-FCV1-011 0.0-0.5T 0.00E+00 5.88E-01 2002X-1-CJ-FCV1-012 0.0-1.0T 7.08E-02 7.36E-02 2002X-1-CJ-FCV1-013 0.0-0.5T 4.49E-02 1.48E+00 2002X-1-CJ-FCV1-014 0.0-0.5T 5.06E-02 8.48E-01 2002X-1-CJ-FCV1-015 0.0-0.5T 3.00E-02 1.69E+00 2002X-1-CJ-WCV1-016 0.0-0.5T 2.77E-02 3.36E-01 2002X-1-CJ-WCV1-017 0.0-0.5T 5.16E-01 7.63E-01 2002X-1-CJ-WCV1-018 0.0-0.5T 1.34E-01 1.03E+00 Maximum 1.58E+02 2.50E+03 Mean 1.44E+01 2.72E+02 Standard Deviation 3.84E+01 7.45E+02 The statistical results in pCi/g from Table 9 are converted to pCi/m2 In Table 10 below.
Table 10: Statistical Parameters for Gamma Emitting ROCs Statistical parameter Co-60 (pCi/m2)
Cs-137 (pCi/m2)
Maximum 5.10E+06 8.06E+07 Mean 4.64E+05 8.76E+06
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 18 of 40 Statistical parameter Co-60 (pCi/m2)
Cs-137 (pCi/m2)
Standard Deviation 1.24E+06 2.40E+07 The depth of contamination in the concrete surfaces of the East Trenches was also determined. This was done by analyzing the concrete disc samples from continuing characterization using the on-site gamma spectroscopy systems. Six of the eighteen core samples broke apart during collection and the cores could not be Those samples were not included in this analysis.
Incremental disc samples, starting with the disc representing the shallowest location depth (i.e., closest to the surface), were analyzed at each location until the concentrations were less than the prescribed MDC.
The results of the depth analysis are contained in Table 11 below. The bold values represent positive detections.
Table 11: East Trenches Contamination Depth Analysis Sample ID Cs-137 (pCi/g) 0.0 - 0.5" Depth 0.5 - 1.0" Depth Total 2002X-1-CJ-FCVX-001 5.27E-01 3.12E-01 8.39E-01 2002X-1-CJ-FCVX-003 1.97E+00 7.41E-02 2.04E+00 2002X-1-CJ-FCVX-004 0.00E+00 2.56E-01 2.56E-01 2002X-1-CJ-FCVX-005 5.19E+03 4.72E-02 5.19E+03 2002X-1-CJ-FCVX-009 6.85E-01 6.92E-01 1.38E+00 2002X-1-CJ-FCVX-010 4.55E+03 3.68E-01 4.55E+03 2002X-1-CJ-FCVX-013 1.95E+00 0.00E+00 1.95E+00 2002X-1-CJ-FCVX-014 1.77E+00 2.49E+00 4.26E+00 2002X-1-CJ-FCVX-015 2.28E+00 1.53E-01 2.43E+00 2002X-1-CJ-WCVX-016 7.70E-01 1.82E-01 9.52E-01 2002X-1-CJ-WCVX-017 3.05E+00 1.90E-01 3.24E+00 2002X-1-CJ-WCVX-018 3.40E+00 5.96E-01 4.00E+00 Sum 9.76E+03 5.36E+00 9.76E+03 99.95%
0.05%
100.00%
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 19 of 40 6.3 Radionuclide Mixture Fraction The evaluation provided in this section determines the radionuclide mixture fraction based on the analytical results. This will be used to calculate the radionuclide fractional abundances.
The evaluation provided in this section determines the radionuclide mixture fractions of the initial suite of radionuclides and selects the radionuclides that are
-1757, Vol. 2, Rev 1 The radionuclides remaining after the insignificant dose contributors are eliminated are the radionuclides of concern (ROCs).
The insignificant contributor (IC) dose fraction will be accounted for by adjusting the final DCGLs for each ROC. This section is divided into two subsections; one for determining radionuclide mixture fractions using three methods, and a second to establish the IC dose fraction.
The radionuclide mixture fraction will be used in conjunction with the dose assessment methods in Chapter 6 of the LTP to calculate the relative dose significance of the radionuclides in the initial suite.
The radionuclide mixture fractions are derived from the results of the 7 concrete core samples.
The radionuclide fractions were determined from the decay corrected analytical data using three separate approaches as described below. The three methods were chosen to represent common and conservative methods in determining activity fractions to ensure that the final selection of the radionuclide mixtures accounts for variability and represent conservative estimates. Each of the three analysis methods use the actual reported laboratory values, whether detected or less than the reported MDC values. All negative results were reset to zero to avoid generating fractional results greater than one. The results were decay corrected from the date of sample analysis to the anticipated date of license termination. The Am-241 results also account for the in-growth from Pu-241.
- 1. The first method was to calculate the radionuclide activity fraction, fAi,j,k, for each sample, j, each radionuclide, i, within the sample population, k, from the reported decay corrected radionuclide activity concentrations, Ci,j,k, using Equation 2 and then calculating the average activity fraction, fAi,j,k, for each radionuclide, i, and population, k, of N samples using Equation 3.
Equation 2
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 20 of 40 Equation 3
- 2. The second was to calculate the 75th percentile of the population of samples from Equation 2 above. Once the 75th percentile fraction were calculated for each radionuclide, fi,k,.75, the data set was re-normalized to determine the percentile-based activity fractions, fAi,k,.75 using Equation 4.
Equation 4
- 3. The third was to calculate the individual radionuclide ratios to Cs-137 for each sample, Ri,Cs-137,j, calculate the 75th percentile for the sample group, Ri,Cs-137,k,.75 then renormalize to determine the activity fractions, fRAi,k,.75 using Equation 5.
Equation 5 The analyses described above remove the activity weighting and give equal statistical weight to each of the sample results. The results of the three methods are provided within each of the following subsections.
Tables 12 through 14 provide the radionuclide activity fractions for all sample data that represent the East Trench mixture. The data is subdivided into three tables to allow for convenient inspection of all 22 radionuclides. The last three rows of these tables provide the average fraction, the 75th percentile of each fractional data set, and the normalized 75th data set as described above. Tables 15 through 17 provide the radionuclide activity ratios to Cs-137 for all sample data. Similarly, to the previous three tables, the data is subdivided into three tables to allow for convenient inspection of all 22 radionuclides. The last two rows of these tables provide the 75th percentile of each ratio data set, and the normalized 75th data set as described above.
Page 21 of 40 Table 12: Radionuclide Activity Fractions, fAi,j and fAi,j,.75, First Set of Radionuclides Sample ID H-3 C-14 Fe-55 Co-58 Ni-59 Co-60 Ni-63 Sr-90 2002X-1-CJ-FCV1-003 0.0-0.5T 6.34E-01 0.00E+00 0.00E+00 0.00E+00 1.98E-02 2.35E-03 9.83E-02 1.36E-02 2002X-1-CJ-FCV1-005 0.0-0.5 3.04E-03 2.42E-02 9.66E-04 3.85E-10 2.39E-03 8.65E-03 2.56E-01 2.55E-03 2002X-1-CJ-FCV1-006T 3.31E-04 7.27E-02 1.35E-03 4.39E-08 2.51E-03 5.57E-02 4.33E-01 2.89E-03 2002X-1-CJ-FCV1-007T 9.69E-03 1.08E-01 2.77E-02 0.00E+00 5.68E-03 1.27E-01 3.89E-01 5.47E-05 2002X-1-CJ-FCV1-010 0.0-0.5 4.22E-03 1.17E-01 4.61E-03 1.32E-08 1.16E-03 3.56E-02 1.89E-01 1.96E-03 2002X-1-CJ-WCV1-017 0.0-0.5T 4.18E-01 1.99E-01 2.91E-02 4.44E-07 0.00E+00 4.42E-02 0.00E+00 4.17E-03 2002X-1-CJ-WCV1-018 0.0-0.5T 1.16E-01 0.00E+00 0.00E+00 0.00E+00 0.00E+00 3.41E-02 2.61E-01 0.00E+00 Average 1.69E-01 7.44E-02 9.10E-03 7.17E-08 4.50E-03 4.39E-02 2.32E-01 3.61E-03 75 Percentile Frac.
2.67E-01 1.13E-01 1.61E-02 2.86E-08 4.09E-03 4.99E-02 3.25E-01 3.53E-03 75 Perc. Norm. Frac.
1.85E-01 7.84E-02 1.12E-02 1.99E-08 2.85E-03 3.47E-02 2.26E-01 2.46E-03 Table 13: Radionuclide Activity Fractions, fAi,j and fAi,j,.75, Second Set of Radionuclides Sample ID Tc-99 Sb-125 Cs-134 Cs-137 Ce-144 Eu-152 Eu-154 2002X-1-CJ-FCV1-003 0.0-0.5T 1.05E-01 0.00E+00 5.49E-03 7.80E-02 0.00E+00 1.53E-02 1.41E-02 2002X-1-CJ-FCV1-005 0.0-0.5 1.11E-02 0.00E+00 7.41E-05 6.91E-01 4.21E-05 1.11E-04 3.09E-05 2002X-1-CJ-FCV1-006T 5.91E-03 2.12E-04 8.49E-05 4.23E-01 4.51E-05 0.00E+00 4.38E-04 2002X-1-CJ-FCV1-007T 7.50E-03 1.63E-04 4.01E-04 3.16E-01 6.09E-05 3.20E-04 9.52E-04 2002X-1-CJ-FCV1-010 0.0-0.5 8.78E-03 2.27E-04 7.02E-05 6.35E-01 0.00E+00 2.96E-04 6.59E-05 2002X-1-CJ-WCV1-017 0.0-0.5T 1.17E-01 0.00E+00 1.46E-03 8.74E-02 1.20E-03 0.00E+00 7.23E-03 2002X-1-CJ-WCV1-018 0.0-0.5T 1.97E-01 0.00E+00 1.06E-02 3.50E-01 0.00E+00 0.00E+00 0.00E+00 Average 6.47E-02 8.60E-05 2.60E-03 3.69E-01 1.92E-04 2.29E-03 3.26E-03 75 Percentile Frac.
1.11E-01 1.88E-04 3.47E-03 5.29E-01 5.30E-05 3.08E-04 4.09E-03 75 Perc. Norm. Frac.
7.74E-02 1.30E-04 2.42E-03 3.68E-01 3.68E-05 2.14E-04 2.85E-03
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 22 of 40 Table 14: Radionuclide Activity Fractions, fAi,j and fAi,j,.75, Third Set of Radionuclides Sample ID Eu-155 Np-237 Pu-238 Pu-239/240 Am-241 Pu-241 Cm-243/244 2002X-1-CJ-FCV1-003 0.0-0.5T 0.00E+00 1.00E-03 5.57E-03 7.57E-03 0.00E+00 0.00E+00 0.00E+00 2002X-1-CJ-FCV1-005 0.0-0.5 5.61E-05 0.00E+00 2.39E-05 0.00E+00 4.48E-06 3.57E-04 2.86E-05 2002X-1-CJ-FCV1-006T 2.14E-04 0.00E+00 2.06E-04 8.36E-05 9.35E-04 0.00E+00 0.00E+00 2002X-1-CJ-FCV1-007T 0.00E+00 4.88E-05 7.10E-04 0.00E+00 4.37E-05 6.83E-03 0.00E+00 2002X-1-CJ-FCV1-010 0.0-0.5 0.00E+00 5.48E-07 7.34E-05 1.91E-05 7.32E-06 6.45E-04 1.23E-04 2002X-1-CJ-WCV1-017 0.0-0.5T 0.00E+00 2.44E-04 3.49E-03 0.00E+00 6.87E-04 8.35E-02 4.14E-03 2002X-1-CJ-WCV1-018 0.0-0.5T 1.36E-02 0.00E+00 1.12E-02 0.00E+00 4.82E-04 0.00E+00 5.83E-03 Average 1.98E-03 1.85E-04 3.04E-03 1.10E-03 3.09E-04 1.30E-02 1.45E-03 75 Percentile Frac.
1.35E-04 1.46E-04 4.53E-03 5.14E-05 5.85E-04 3.74E-03 2.13E-03 75 Perc. Norm. Frac.
9.38E-05 1.02E-04 3.15E-03 3.57E-05 4.07E-04 2.60E-03 1.48E-03 Table 15: Radionuclide Activity Ratios to Cs-137, fRAi,j, First Set of Radionuclides Sample ID H-3 C-14 Fe-55 Co-58 Ni-59 Co-60 Ni-63 Sr-90 2002X-1-CJ-FCV1-003 0.0-0.5T 8.12E+00 0.00E+00 0.00E+00 0.00E+00 2.53E-01 3.02E-02 1.26E+00 1.75E-01 2002X-1-CJ-FCV1-005 0.0-0.5 4.40E-03 3.51E-02 1.40E-03 5.57E-10 3.45E-03 1.25E-02 3.70E-01 3.70E-03 2002X-1-CJ-FCV1-006T 7.81E-04 1.72E-01 3.18E-03 1.04E-07 5.93E-03 1.31E-01 1.02E+00 6.83E-03 2002X-1-CJ-FCV1-007T 3.07E-02 3.42E-01 8.75E-02 0.00E+00 1.80E-02 4.00E-01 1.23E+00 1.73E-04 2002X-1-CJ-FCV1-010 0.0-0.5 6.64E-03 1.85E-01 7.26E-03 2.08E-08 1.83E-03 5.60E-02 2.98E-01 3.09E-03 2002X-1-CJ-WCV1-017 0.0-0.5T 4.78E+00 2.27E+00 3.33E-01 5.08E-06 0.00E+00 5.06E-01 0.00E+00 4.77E-02 2002X-1-CJ-WCV1-018 0.0-0.5T 3.30E-01 0.00E+00 0.00E+00 0.00E+00 0.00E+00 9.73E-02 7.45E-01 0.00E+00 75th Percentile Each Sample 2.55E+00 2.63E-01 4.74E-02 6.23E-08 1.19E-02 2.66E-01 1.13E+00 2.73E-02 75th Normalized Fraction 4.01E-01 4.13E-02 7.43E-03 9.77E-09 1.87E-03 4.17E-02 1.77E-01 4.28E-03
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 23 of 40 Table 16: Radionuclide Activity Ratios to Cs-137, fRAi,j, Second Set of Radionuclides Sample ID Tc-99 Sb-125 Cs-134 Cs-137 Ce-144 Eu-152 Eu-154 2002X-1-CJ-FCV1-003 0.0-0.5T 1.35E+00 0.00E+00 7.03E-02 1.00E+00 0.00E+00 1.96E-01 1.81E-01 2002X-1-CJ-FCV1-005 0.0-0.5 1.61E-02 0.00E+00 1.07E-04 1.00E+00 6.09E-05 1.61E-04 4.48E-05 2002X-1-CJ-FCV1-006T 1.39E-02 5.00E-04 2.00E-04 1.00E+00 1.07E-04 0.00E+00 1.03E-03 2002X-1-CJ-FCV1-007T 2.37E-02 5.16E-04 1.27E-03 1.00E+00 1.92E-04 1.01E-03 3.01E-03 2002X-1-CJ-FCV1-010 0.0-0.5 1.38E-02 3.57E-04 1.10E-04 1.00E+00 0.00E+00 4.66E-04 1.04E-04 2002X-1-CJ-WCV1-017 0.0-0.5T 1.34E+00 0.00E+00 1.67E-02 1.00E+00 1.37E-02 0.00E+00 8.27E-02 2002X-1-CJ-WCV1-018 0.0-0.5T 5.64E-01 0.00E+00 3.04E-02 1.00E+00 0.00E+00 0.00E+00 0.00E+00 75th Percentile Each Sample 9.52E-01 4.29E-04 2.36E-02 1.00E+00 1.50E-04 7.39E-04 4.29E-02 75th Normalized Fraction 1.49E-01 6.73E-05 3.70E-03 1.57E-01 2.35E-05 1.16E-04 6.73E-03 Table 17: Radionuclide Activity Ratios to Cs-137, fRAi,j, Third Set of Radionuclides Sample ID Eu-155 Np-237 Pu-238 Pu-239/240 Am-241 Pu-241 Cm-243/244 2002X-1-CJ-FCV1-003 0.0-0.5T 0.00E+00 1.28E-02 7.15E-02 9.71E-02 0.00E+00 0.00E+00 0.00E+00 2002X-1-CJ-FCV1-005 0.0-0.5 8.12E-05 0.00E+00 3.46E-05 0.00E+00 6.49E-06 5.16E-04 4.15E-05 2002X-1-CJ-FCV1-006T 5.05E-04 0.00E+00 4.87E-04 1.97E-04 2.21E-03 0.00E+00 0.00E+00 2002X-1-CJ-FCV1-007T 0.00E+00 1.54E-04 2.25E-03 0.00E+00 1.38E-04 2.16E-02 0.00E+00 2002X-1-CJ-FCV1-010 0.0-0.5 0.00E+00 8.62E-07 1.15E-04 3.01E-05 1.15E-05 1.02E-03 1.93E-04 2002X-1-CJ-WCV1-017 0.0-0.5T 0.00E+00 2.79E-03 4.00E-02 0.00E+00 7.86E-03 9.55E-01 4.74E-02 2002X-1-CJ-WCV1-018 0.0-0.5T 3.88E-02 0.00E+00 3.20E-02 0.00E+00 1.38E-03 0.00E+00 1.66E-02 75th Percentile Each Sample 2.93E-04 1.47E-03 3.60E-02 1.14E-04 1.79E-03 1.13E-02 8.42E-03 75th Normalized Fraction 4.60E-05 2.31E-04 5.65E-03 1.78E-05 2.81E-04 1.77E-03 1.32E-03
Page 24 of 40 Table 18 summarizes the radionuclide activity fractions using the three methods described above.
Table 18: Radionuclide Activity Fractions for East Trench Sample Population Using Three Methods Radionuclide Average Activity Fractions,
- fAi, 75th Percentile of the Activity Average Fractions, fAi,,.75 75th Percentile of the Individual Sample Ratios to Cs-137, fRAi,.75 H-3 1.69E-01 1.85E-01 4.01E-01 C-14 7.44E-02 7.84E-02 4.13E-02 Fe-55 9.10E-03 1.12E-02 7.43E-03 Co-58 7.17E-08 1.99E-08 9.77E-09 Ni-59 4.50E-03 2.85E-03 1.87E-03 Co-60 4.39E-02 3.47E-02 4.17E-02 Ni-63 2.32E-01 2.26E-01 1.77E-01 Sr-90 3.61E-03 2.46E-03 4.28E-03 Tc-99 6.47E-02 7.74E-02 1.49E-01 Sb-125 8.60E-05 1.30E-04 6.73E-05 Cs-134 2.60E-03 2.42E-03 3.70E-03 Cs-137 3.69E-01 3.68E-01 1.57E-01 Ce-144 1.92E-04 3.68E-05 2.35E-05 Eu-152 2.29E-03 2.14E-04 1.16E-04 Eu-154 3.26E-03 2.85E-03 6.73E-03 Eu-155 1.98E-03 9.38E-05 4.60E-05 Np-237 1.85E-04 1.02E-04 2.31E-04 Pu-238 3.04E-03 3.15E-03 5.65E-03 Pu-239/240 1.10E-03 3.57E-05 1.78E-05 Am-241 3.09E-04 4.07E-04 2.81E-04 Pu-241 1.30E-02 2.60E-03 1.77E-03 Cm-243/244 1.45E-03 1.48E-03 1.32E-03 6.4 Insignificant Contributors to Dose NUREG-less than 10% of the total dose from all radionuclides combined. The
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 25 of 40 insignificant contributors can be eliminated from further detailed consideration in the LTP and FSS. However, the dose contribution from the insignificant contributors must be accounted for in the final DCGLs. The radionuclides remaining after the insignificant contributors are removed are the ROCs for the East Trenches.
The ROCs were selected to ensure that sufficient margin has been attributed to the estimated dose contribution from the insignificant radionuclides. This decreases the risk of having to recalculate the adjusted DCGLS.
The Relative Dose Fraction, RDFi,k, for nuclide i and population k is calculated using the applicable DCGLs from Table 2, and the nuclide activity fraction from Section 6.3 and Equation 6.
Equation 6 The values of are listed in Table 2.
It should be noted that for the nuclide pairs Pu-239/240 and Cm-243/244 that the most limiting DCGL for each pair was selected for use in Equation 6. Tables 19 and 20 show the results of the RDF calculations using the 75th Percentile of the Activity Average Fractions and the 75th Percentile of the Individual Sample Ratios to Cs-137.
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 26 of 40 Table 19: Relative Dose Fractions, RDFi,k, East Trench Mix Fraction, Using 75th Percentiles of the Averages Nuclide ROC?
East Trench Mix Fraction East Trench Dose Fraction H-3 Y
1.85E-01 1.15E-01 C-14 7.84E-02 4.78E-06 Fe-55 1.12E-02 8.32E-08 Co-58 1.99E-08 1.57E-08 Ni-59 2.85E-03 1.09E-07 Co-60 Y
3.47E-02 2.57E-01 Ni-63 2.26E-01 2.36E-05 Sr-90 2.46E-03 4.01E-05 Tc-99 7.74E-02 4.86E-04 Sb-125 1.30E-04 1.38E-04 Cs-134 2.42E-03 9.47E-03 Cs-137 Y
3.68E-01 6.05E-01 Ce-144 3.68E-05 3.88E-06 Eu-152 2.14E-04 7.14E-04 Eu-154 2.85E-03 1.03E-02 Eu-155 9.38E-05 7.92E-06 Np-237 1.02E-04 6.15E-05 Pu-238 3.15E-03 1.50E-04 Pu-239/240 3.57E-05 1.89E-06 Am-241 4.07E-04 3.09E-05 Pu-241 2.60E-03 2.76E-06 Cm-243/244 1.48E-03 4.76E-04 Sum 1.00E+00 ROC 9.78E-01 IC Dose 2.19E-02
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 27 of 40 Table 20: Relative Dose Fractions, RDFi,k, East Trench Mix Fraction, Using 75th Percentiles of the Nuclide Ratios to Cs-137 Nuclide ROC?
East Trench Mix Fraction East Trench Dose Fraction H-3 Y
4.01E-01 2.91E-01 C-14 4.13E-02 2.94E-06 Fe-55 7.43E-03 6.43E-08 Co-58 9.77E-09 8.99E-09 Ni-59 1.87E-03 8.33E-08 Co-60 Y
4.17E-02 3.61E-01 Ni-63 1.77E-01 2.15E-05 Sr-90 4.28E-03 8.15E-05 Tc-99 1.49E-01 1.09E-03 Sb-125 6.73E-05 8.33E-05 Cs-134 3.70E-03 1.69E-02 Cs-137 Y
1.57E-01 3.01E-01 Ce-144 2.35E-05 2.88E-06 Eu-152 1.16E-04 4.51E-04 Eu-154 6.73E-03 2.83E-02 Eu-155 4.60E-05 4.53E-06 Np-237 2.31E-04 1.63E-04 Pu-238 5.65E-03 3.14E-04 Pu-239/240 1.78E-05 1.10E-06 Am-241 2.81E-04 2.49E-05 Pu-241 1.77E-03 2.20E-06 Cm-243/244 1.32E-03 4.95E-04 Sum 1.00E+00 ROC 9.52E-01 IC Dose 4.79E-02 6.5 Selection of Final Nuclide Fraction To support FSS activities, a single radionuclide mix is desired for each potential source-term rather than a set of values as has been used in Section 6.3 representing three statistical/mathematical methods. Evaluation of the three statistical methods, shows that the two methods involving the use of the 75th percentiles result in very similar results, particularly the IC dose fractions.
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 28 of 40 Using the 75th percentile provides sufficient overall conservatism in the development of the radionuclide mixtures. For consistency with previous evaluations done at FCS and for th percentile of the Cs-East Trenches sample population as reproduced in Section 6.4. Table 21 shows the final radionuclide mixture fractions which have been selected. These were the radionuclide mix fractions for the nuclides used to calculate the DCGLS and for the determination of ROCs and IC to dose.
Table 21: Final Radionuclide Mixture Fraction Radionuclide East Trench Final Mix Fraction H-3 4.01E-01 C-14 4.13E-02 Fe-55 7.43E-03 Co-58 9.77E-09 Ni-59 1.87E-03 Co-60 4.17E-02 Ni-63 1.77E-01 Sr-90 4.28E-03 Tc-99 1.49E-01 Sb-125 6.73E-05 Cs-134 3.70E-03 Cs-137 1.57E-01 Ce-144 2.35E-05 Eu-152 1.16E-04 Eu-154 6.73E-03 Eu-155 4.60E-05 Np-237 2.31E-04 Pu-238 5.65E-03 Pu-239/240 1.78E-05 Am-241 2.81E-04 Pu-241 1.77E-03 Cm-243/244 1.32E-03 6.6 ROC Mixture Fractions In order to support gross gamma measurements during characterization and final status surveys, an ROC mixture for gamma emitting radionuclides can be used to
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 29 of 40 calculate the sensitivity of gross gamma detectors for a specific mixture. This determination begins with the re-normalized ROC fractions listed in Table 22 for Section 6.4.
Table 22: ROC Mixture Fraction Radionuclide ROC Mixture Fraction H-3 6.69E-01 Co-60 6.96E-02 Cs-137 2.62E-01 Using the data in Table 22, the ROC mixture fraction for only the gamma emitters is re-normalized against the total gamma ROC activity and shown in Table 23.
Table 23: Gamma ROC Mixture Fraction Radionuclide ROC Mixture Fraction Co-60 2.10E-01 Cs-137 7.90E-01 6.7 Continuing Characterization Surrogate Ratios From the data provided in Sections 6.4 through 6.6, it is evident that Co-60 and Cs-137 are the predominant ROC gamma-emitting radionuclides. Also, H-3 is identified as an ROC while also being a HTD radionuclides. Cs-137 was selected as the most appropriate gamma emitter for the surrogate relationship for H-3.
The ratio of HTDs to gamma emitters is required to develop a surrogate relationship as defined in MARSSIM. The concentration of HTDs can be inferred from the concentration of a gamma emitter in cases where samples are not subject to HTD analysis during FSS activities. Table 23s show the decayed concentrations, MDCs and the Cs-137 ratios for H-3.
Of the 7 samples, 2 of the H-3 and all 7 of the Cs-137 results were greater than the MDC. In the instances where H-3 was not detected at levels above the MDC the decayed MDC is used as the H-3 activity for the ratio calculation.
The average, minimum, maximum, standard deviation, 75th and 95th percentile of the surrogate ratio is shown in Table 25.
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 30 of 40 To account for the variability and level of uncertainty in the data, the 95th percentile values were selected for the final surrogate ratios. Using the 95th percentile value along with the MDC substituted will provide reasonable conservatism during the final status surveys.
Table 24: Continuing Characterization H-3 and Cs-137 Decayed Reported Concentrations, MDCs and Ratios Sample ID H-3 Decayed Reported Conc.
(pCi/g)
Cs-137 Decayed Reported Conc.
(pCi/g)
H-3 Conc.
Using Reported or MDC Values (pCi/g)
Cs-137 Conc. Using Reported or MDC Values (pCi/g)
H-3/Cs-137 Ratio Using Reported or MDC Values 2002X-1-CJ-FCV1-003 0.0-0.5T 3.24E+00 4.91E+00 3.99E-01 1.35E-01 4.91E+00 3.99E-01 1.23E+01 2002X-1-CJ-FCV1-005 0.0-0.5 1.03E+01 4.94E+00 2.35E+03 7.36E-01 1.03E+01 2.35E+03 4.39E-03 2002X-1-CJ-FCV1-006T 1.79E-01 4.93E+00 2.30E+02 4.18E-01 4.93E+00 2.30E+02 2.15E-02 2002X-1-CJ-FCV1-007T 8.24E-01 4.94E+00 2.69E+01 2.59E-01 4.94E+00 2.69E+01 1.84E-01 2002X-1-CJ-FCV1-010 0.0-0.5 1.32E+01 4.93E+00 1.98E+03 1.10E+00 1.32E+01 1.98E+03 6.63E-03 2002X-1-CJ-WCV1-017 0.0-0.5T 3.43E+00 4.97E+00 7.18E-01 1.39E-01 4.97E+00 7.18E-01 6.92E+00 2002X-1-CJ-WCV1-018 0.0-0.5T 3.19E-01 4.94E+00 9.69E-01 1.39E-01 4.94E+00 9.69E-01 5.09E+00 Table 25: Continuing Characterization H-3/Cs-137 Ratio Parameter East Trench Sample Population Average 3.51E+00 Minimum 4.39E-03 Maximum 1.23E+01 Std. Dev.
4.82E+00 75th Percentile 6.01E+00 95th Percentile 1.07E+01 6.8 RASS Surrogate Ratios During the RASS, 12 concrete core samples were obtained from the locations with the highest hand-scan or ISOCS scan results. The sample results are reported in GEL Work Order 658343 (Ref. 8.17). The H-3/Cs-137 ratios were compared to the ratio from the Continuing Characterization samples in Section 6.7 in accordance with the requirements of Section 5.2.5 of the LTP.
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 31 of 40 One of the samples, 2002X-1-RJ-WCV1-130 0.0-0.5T, had a higher H-3/Cs-137 ratio then the results calculated in Section 6.7. In this situation the LTP requires that the maximum value be used as the surrogate ratio for the Sample Unit.
Section 5.2.5 of the LTP requires that if the analysis indicates positive results (greater than MDC) for both an HTD ROC and the corresponding surrogate radionuclide, then the HTD to surrogate ratio will be calculated. If the calculated HTD to surrogate ratio is less than the applicable HTD to surrogate ratio, then no further action is required. The actual maximum HTD to surrogate ratio observed in any individual sample will be used to infer HTD radionuclide concentrations in the survey units shown to be impacted by the investigation. The survey unit-specific HTD to surrogate ratio and the survey data serving as the basis for the ratio will be documented in the release record for the survey unit(s).
The reported results of the RASS samples are contained in Table 26. The decay corrected values and calculated surrogate ratios are contained in Table 27.
Table 26: RASS Core Sample Results for H-3 and Cs-137 Sample ID H-3 Reported Conc.
(pCi/g)
Cs-137 Reported Conc.
(pCi/g)
Cs-137 MDCs (pCi/g) 2002X-1-RJ-FCV1-082 0.0-1.0T
-1.12E-02 5.90E+00 2.83E-01 9.99E-02 2002X-1-RJ-FCV1- 083 0.0-0.5T
-8.96E-01 6.02E+00 3.13E+00 1.33E-01 2002X-1-RJ-FCV1-110 0.0-0.5T 1.81E+00 5.71E+00 1.28E+00 1.89E-01 2002X-1-RJ-FCV1-116 0.0-0.5T 1.65E+01 6.02E+00 5.49E-03 1.30E-01 2002X-1-RJ-FCV1-128 0.0-0.5T 1.20E-01 5.82E+00 1.09E-01 1.28E-01 2002X-1-RJ-WCV1-130 0.0-0.5T 2.48E+01 5.90E+00 6.99E-01 1.37E-01 2002X-1-RJ-WCV1-134 0.0-1.5T 1.26E+01 5.94E+00 2.26E+01 1.44E-01 2002X-1-RJ-FCV1-137 0.0-0.5T 1.63E+01 5.99E+00 1.27E-02 1.36E-01 2002X-1-RJ-WCV1-140 0.0-0.5T 9.07E+00 5.84E+00 5.50E+01 2.93E-01 2002X-1-RJ-FCV1-142 0.0-0.5T 8.56E+00 5.94E+00 4.99E+01 2.43E-01 2002X-1-RJ-WCV1-147 0.0-1.0T 2.17E+00 5.91E+00 5.31E+01 1.60E-01 2002X-1-RJ-WCV1-148 0.0-2.0T 2.03E+01 5.95E+00 5.24E+00 1.60E-01
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 32 of 40 Table 27: RASS Core Sample Decay Corrected Results for H-3 and Cs-137 Sample ID H-3 Decayed Conc.
(pCi/g)
Cs-137 Decayed Reported Conc.
(pCi/g)
H-3 Conc.
Greater Than MDC ?
Cs-137 Conc.
Greater Than MDC?
2002X-1-RJ-FCV1-082 0.0-1.0T
-9.69E-03 5.10E+00 2.67E-01 9.41E-02 Y
2002X-1-RJ-FCV1- 083 0.0-0.5T
-7.75E-01 5.21E+00 2.95E+00 1.25E-01 Y
2002X-1-RJ-FCV1-110 0.0-0.5T 1.57E+00 4.94E+00 1.21E+00 1.78E-01 Y
2002X-1-RJ-FCV1-116 0.0-0.5T 1.43E+01 5.21E+00 5.17E-03 1.22E-01 Y
2002X-1-RJ-FCV1-128 0.0-2.0T 1.04E-01 5.04E+00 1.03E-01 1.21E-01 2002X-1-RJ-WCV1-130 0.0-0.5T 2.15E+01 5.10E+00 6.59E-01 1.29E-01 Y
Y 2002X-1-RJ-WCV1-134 0.0-1.5T 1.09E+01 5.14E+00 2.13E+01 1.36E-01 Y
Y 2002X-1-RJ-FCV1-137 0.0-0.5T 1.41E+01 5.18E+00 1.20E-02 1.28E-01 Y
2002X-1-RJ-WCV1-140 0.0-0.5T 7.85E+00 5.05E+00 5.18E+01 2.76E-01 Y
Y 2002X-1-RJ-FCV1-142 0.0-0.5T 7.41E+00 5.14E+00 4.70E+01 2.29E-01 Y
Y 2002X-1-RJ-WCV1-147 0.0-1.0T 1.88E+00 5.11E+00 5.00E+01 1.51E-01 Y
2002X-1-RJ-WCV1-148 0.0-2.5T 1.76E+01 5.15E+00 4.94E+00 1.51E-01 Y
Y Table 28: RASS Core Sample Surrogate Ratios Sample ID H-3/Cs-137 Ratio 2002X-1-RJ-FCV1-130 0.0-1.0T 3.26E+01 2002X-1-RJ-FCV1-134 0.0-0.5T 5.12E-01 2002X-1-RJ-FCV1-140 0.0-0.5T 1.51E-01 2002X-1-RJ-FCV1-142 0.0-0.5T 1.58E-01 2002X-1-RJ-FCV1-148 0.0-0.5T 3.56E+00
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 33 of 40 As the ratio of 32.6 for sample 2002X-1-RJ-FCV1-130 0.0-1.0T is greater than the value of 10.7 calculated in Section 6.7, it now becomes the H-3/Cs-137 surrogate value. The other four core sample results were less than the value calculated in Section 6.7. As the use of this surrogate value would result in scan MDCs greater than the OpDCGL. The Base Case DCGLs will be used for comparing to the scan MDCs and determining action levels.
Using the appropriate scaling factors, the DCGL of the measured radionuclide is modified to account for the represented radionuclide, according to the following equation from Section 4.3.2 of MARSSIM. This is designated as Equation 5-2 in the LTP and is reproduced below. Effective Base case DCGLs for use with the East Trench surveys are provided in Table 26.
Table 29: Effective DCGLs ETD Nuclide HTD Nuclide East Trench Effective DCGL (pCi/m2)
Co-60 NA 1.41E+08 Cs-137 H-3 4.76E+07 Co-60 + Cs-137 H-3 5.53E+07 7.0 SURVEY METHODOLOGY The FSS is used to verify that the potential dose from residual radioactivity is below the release criterion for each survey unit. For this Class 1 survey unit, 100% of the accessible surfaces of the trench floors and walls will be scanned using a combination of in situ gamma spectroscopy (ISOCS) and NaI detectors (e.g., Ludlum 3001 (or equivalent) coupled to a collimated 44-10. Compliance will
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 34 of 40 be demonstrated through the collection and analysis of systematic concrete core samples.
7.1 Scan Surveys The ISOCS will primarily be used to scan the accessible floors of the trenches and the 44-10 NaI detectors will be used in all other areas. Hand scanned areas will overlap with ISOCS scan areas.
TSD FC Ludlum 44-10 Detector Sensitivity for Determining Scan MDCs on Concrete Surfaces provides guidance on determining the scan sensitivities for concrete surfaces.
TSD FC Use of In-situ Gamma Spectroscopy for Scan Surveys provides details of using in-situ gamma spectroscopy for scan surveys of building surfaces.
Scans of all trench walls will be performed to identify any elevated radiation purpose of this is to identify and evaluate any elevated radiation levels in the top The ISOCS geometries to be used for this survey are specific to this survey unit.
Each survey grid location will have a predefined geometry assigned to it. Various ISOCS geometries will be utilized due to the differences in dimensions of the trenches. LT/FSS Supervision will determine which ISOCS geometry to be used, the height from desired target, and distance from each surrounding measurement. To ensure 100% areal coverage with ISOCS measurements, the Field of View (FOV) for each ISOCS scan measurement will overlap with adjacent measurements.
Per Table 5-23 of the LTP, direct and scanning measurements should be flagged at greater than the DCGL. The FSS plan will be written to utilize the MDCRSurveyor as the alarm set point, therefore the scanning requirement of Table 5-23 of the LTP is satisfied.
7.2 Systematic Sampling Compliance will be demonstrated through the collection and analysis of systematic concrete core samples. The sample locations will be generated by VSP using a triangular grid with a random starting point. The number of samples will be specified in the FSS plan.
7.3 Investigation Levels
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 35 of 40 Investigation and Action Levels will be based on the Base Case DCGL for scanning with a NaI detector or ISOCS detector and on-site analysis. For a Class 1 survey unit the Investigation Level is set at the Base case DCGL. Section 5.2.5 of the LTP states:
Radiation detection and measurement instrumentation will be selected based on the type and quantity of radiation to be measured. For direct measurements and sample analyses, MDCs less than 10% of the Operational DCGL are preferable while MDCs up to 50% of the Operational DCGL are acceptable. Instruments used for scan measurements in Class 1 areas are required to be capable of detecting radioactive material at the Base Case DCGL. Measurement results with associated MDC that exceed these values may be accepted as valid data after evaluation by FSS supervision. The evaluation will consider the actual MDC, the reported value for the measurement result, the reported uncertainty and the fraction of the Operational DCGL identified in the sample.
For the ISOCS, the Derived Investigation Levels will be calculated that include an offset geometry correction factor. For this survey unit the offset correction factor uses the most conservative value for any combination of detector and geometry.
Section 5.5.5.2 of the LTP states that any areas of elevated residual radioactivity above the Base Case DCGL will be remediated. If an area is remediated, then a RASS will be performed to ensure that the remediation was sufficient.
7.4 Investigations If the results of an individual scan measurement show elevated activity, an investigation may be performed at the discretion of LT/FSS Supervision.
Investigations will consist of scan surveys utilizing a Model 3001 instrument coupled to a collimated Model 44-10 NaI detector. The ISOCS may also be used for additional investigational surveys of elevated areas.
LT/FSS Supervision will review the results of the scan surveys and determine the location(s) for gross gamma static measurement(s). The selection of the locations will be based on the results of the scan surveys.
At the discretion of LT/FSS Supervision, a concrete core may be collected for analysis at the location(s) of the gross gamma static measurements.
7.5 Concrete Core Samples Concrete core samples will be taken in accordance with the FSS Plan. Each core will go to a depth of 4 inches if the trench configuration allows and then be cut into 1/2 inch disks for on-site analysis. It should be noted that some trench floors the cores will be as deep as the structural integrity will allow.
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 36 of 40 Incremental disk samples, starting with the disk representing the shallowest location depth (closest to the surface) for each sample location, will be analyzed by gamma spectroscopy until the analysis shows concentrations less than the prescribed MDC. Samples not requiring analysis will be archived.
Samples will be counted to an MDA of less than 1 pCi/g for Co-60 and less than 1.0 pCi/g for Cs-137. Count times and MDAs may be altered with approval of the LT/FSS Manager.
7.6 Data Assessment Data assessment will be in accordance with FCSD-RA-LT-304 Final Status Survey Data Assessment (Ref 8.16).
Area Factors, in accordance with the guidance in MARSSIM, may be used in the assessment of compliance for this survey unit. This is an exception to the requirements of FCSD-RA-LT-304 and to the requirements of the LTP. The LTP and FCSD-RA-LT-304 will be revised to reflect this change.
Equation 5-8 of the LTP will be used to determine compliance when Area Factors are used. This equation is reproduced below.
7.7 Quality Control Measurements Quality Control (QC) measurements will be collected to satisfy the 5%
requirement from the Quality Assurance Project Plan (Ref. 8.15) for QC measurements. The QC measurements will be determined based on the total
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 37 of 40 numbers of measurements collected during the survey, utilizing a random number generator to determine the locations for QC measurements.
8.0 REFERENCES 8.1 Fort Calhoun Station Decommissioning Project License Termination Plan Revision 1, 2023.
8.2 Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM),
NUREG-1575, Revision 1 August, 2000.
8.3 Consolidated Decommissioning Guidance, Characterization, Survey, and Determination of Radiological Criteria, NUREG-1757, Vol. 2, Revision 1.
8.4 TSD 21-043 Radionuclides of Concern in Support of the Fort Calhoun License Termination Plan 8.5 Continuing Characterization Plan 2002-C.
8.6 TSD FC-24-001 Use of In-situ Gamma Spectroscopy for Scan Surveys 8.7 TSD FC Radionuclide Release Through Grouted Trenches 8.8 TSD FC-24-0 Ludlum 44-10 Detector Sensitivity for Determining Scan MDCs on Concrete Surfaces 8.9 GEL Laboratories LLC, WO No. 637320, Charleston, SC, 2023.
8.10 GEL Laboratories LLC, WO No. 637320, Charleston, SC, 2023.
8.11 Estimates for Release of Radionuclides from Potentially Contaminated Concrete at the Haddam Neck Nuclear Power Plant BNL-73965-2005-IR, 2004.
8.12 Zion Station Restoration Project License Termination Plan, Revision 3, 2020.
8.13 NASA Safety and Mission Assurance Directorate, Final Status Survey Plan for the Plum Brook Reactor Facility, Revision 1, February 2007.
8.14 Continuing Characterization Plan 2002-C.
8.15 FCSD-RA-LT-100 Quality Assurance Project Plan for the License Termination Plan Development, Site Characterization and Final Status Survey Projects at Fort Calhoun Station 8.16 FCSD-RA-LT-Final Status Survey Data Assessment
DCGLs, Remediation Strategy and Survey Methodology for the Auxiliary Building East Trenches FC-24-004 Revision 1 Page 38 of 40 9.0 ATTACHMENTS 9.1 : Configuration of A
FC-18-008 Revision 0 Page 39 of 40 Trenches
FC-18-008 Revision 0 Page 40 of 40