ML22269A392

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01-Responses to NRC Questions from July 5 - 2022
ML22269A392
Person / Time
Site: La Crosse  File:Dairyland Power Cooperative icon.png
Issue date: 09/07/2022
From:
LaCrosseSolutions
To:
Office of Nuclear Material Safety and Safeguards
Shared Package
ML22269A395 List:
References
LS-2022-0019
Download: ML22269A392 (16)
v • d • e


Text

Responses to NRC July 5 Questions and July 7, 2022 Call

Question 1:

General. Is there a procedure for establishing background radiation levels in land survey areas (specifically excavation areas)? How was background established for the survey scans?

LaCrosseSolutions Response:

As discussed in the responses to Questions 7 and 16 from the June 6, 2022 call, the process for acquiring background measurements for scanning of excavations or open land areas was not procedurally established at LACBWR. Rather, background measurement collection requirements were denoted in the instructions of each FSS sample plan, with more detailed instruction provided through technician training and field supervisor instruction.

Question 2:

B1-010- 004. The November 2020 RAI response (RAI 1e) indicated that the pre - and post-rain event scan data for the WGTV was included in the revised release record, but the pre and post scan data from before and after the rain event that caused intrusion to the WGTV Basement does not seem to be in the revised release record. Please verify that Revision 1 of the release record is the correct revision that is meant to have the pre - and post-rain event scan data.

LaCrosseSolutions Response:

Revision 1 of the release record is the correct revision. In revision 1 to the release record for survey unit B1- 010- 004, pre-and post -rain scan data summaries are provided in section 6. For the pre-rain turnover survey data,the release record states, The maximum scan reading captured was 10,276 cpm. No alarms were produced during the performance of this survey. For the post -

rain surveillance survey data, the release record states, The maximum scan reading captured during this surveillance survey was 14,383 cpm. No alarms were produced during the performance of this survey.

The Ludlum 2350- 1 download reports for the pre-and post -rain scan data are below.

Figure 1 - Pre-Rain Scan Download [1]

1 Figure 2 - Pre-Rain Scan Download [2]

Figure 3 - Post-Rain Scan Download [1]

Figure 4 - Post-Rain Scan Download [2]

Question 3:

B1-010- 004. The maximum insignificant contributor (IC) dose calculated by the licensee for the continuing characterization samples was 0.5042 mrem/yr for the concrete core samples and

2 0.1437 mrem/yr for the soil samples, which is below the 2.5 mrem/yr limit provided in the LTP for DCGL adjustment. Please provide the detailed calculations for this maximum IC dose.

LaCrosseSolutions Response:

The calculation is performed as follows: Radioisotope results are tabulated and negative results are zeroed. Positive results, whether above MDA or not, are then divided by the associated Base Case DCGLs as provided in Table 6-6 for soils or Table 6-16 for concrete in Chapter 6 of the LTP. Concrete results in pCi/g need to be converted to pCi/m2, or the DCGLs converted to pCi/g to assign a percentage of dose. The conversion from pCi/g to pCi/m2 is detailed in the response to Question 5. The fractions of the DCGL for the individual radionuclides are then multiplied by 25 to obtain a mrem/yr value for that radioisotope. The IC radionuclide doses (all doses but Co-60, Sr-90, Cs-137, Eu-152 and Eu-154) are then summed to obtain a total mrem/yr value for the IC dose. Below are the calculations for the two samples referenced in the question:

Base Case Remove Radionuclide DCGL (pCi/m2) Sample Activity (pCi/m2)NegativeFraction Dose IC Dose H-3 5.91E+09 B1-010-04A-CJFC-009-CV 1.06E+05 1.06E+05 0.0000 0.0005 C-14 5.33E+08 B1-010-04A-CJFC-009-CV -2.10E+04 0.00E+00 0.0000 0.0000 Fe-55 2.32E+10 B1-010-04A-CJFC-009-CV -8.79E+04 0.00E+00 0.0000 0.0000 Ni-59 2.09E+11 B1-010-04A-CJFC-009-CV -6.56E+03 0.00E+00 0.0000 0.0000 Co-60 6.42E+06 B1-010-04A-CJFC-009-CV 7.45E+02 7.45E+02 0.0001 0.0029 Ni-63 8.49E+10 B1-010-04A-CJFC-009-CV 2.73E+04 2.73E+04 0.0000 0.0000 Sr-90 1.18E+07 B1-010-04A-CJFC-009-CV 3.04E+03 3.04E+03 0.0003 0.0064 Nb-94 1.05E+07 B1-010-04A-CJFC-009-CV -8.37E+02 0.00E+00 0.0000 0.0000 T c-99 1.50E+08 B1-010-04A-CJFC-009-CV 1.96E+03 1.96E+03 0.0000 0.0003 Cs-137 2.82E+07 B1-010-04A-CJFC-009-CV 1.59E+05 1.59E+05 0.0056 0.1405 Eu-152 1.51E+07 B1-010-04A-CJFC-009-CV 2.57E+03 2.57E+03 0.0002 0.0043 Eu-154 1.39E+07 B1-010-04A-CJFC-009-CV -4.35E+03 0.00E+00 0.0000 0.0000 Eu-155 5.77E+08 B1-010-04A-CJFC-009-CV 2.00E+03 2.00E+03 0.0000 0.0001 Np-237 1.51E+05 B1-010-04A-CJFC-009-CV 3.04E+03 3.04E+03 0.0201 0.5032 P u-238 1.77E+07 B1-010-04A-CJFC-009-CV -1.05E+02 0.00E+00 0.0000 0.0000 P u-239 1.46E+07 B1-010-04A-CJFC-009-CV -1.05E+02 0.00E+00 0.0000 0.0000 P u-240 1.46E+07 B1-010-04A-CJFC-009-CV -1.05E+02 0.00E+00 0.0000 0.0000 P u-241 7.81E+08 B1-010-04A-CJFC-009-CV -6.11E+03 0.00E+00 0.0000 0.0000 Am-241 2.75E+07 B1-010-04A-CJFC-009-CV -4.47E+02 0.00E+00 0.0000 0.0000 Am-243 2.16E+07 B1-010-04A-CJFC-009-CV -1.24E+02 0.00E+00 0.0000 0.0000 Cm-243 6.66E+07 B1-010-04A-CJFC-009-CV 9.98E+01 9.98E+01 0.0000 0.0000 Cm-244 1.34E+08 B1-010-04A-CJFC-009-CV 9.98E+01 9.98E+01 0.0000 0.0000 0.5042

3 Base Case Activity Remove Radionuclide DCGL (pCi/g) Sample (pCi/g) Negative Fraction Dose IC Dose H-3 1.75E+04 B1-010-04A-CJFS-004-SB3.54E+00 3.54E+00 0.0002 0.0051 C-14 2.45E+05 B1-010-04A-CJFS-004-SB9.13E-01 9.13E-01 0.0000 0.0001 Fe-55 1.02E+07 B1-010-04A-CJFS-004-SB-1.12E+00 0.00E+00 0.0000 0.0000 Ni-59 2.59E+07 B1-010-04A-CJFS-004-SB6.67E-01 6.67E-01 0.0000 0.0000 Co-60 1.28E+01 B1-010-04A-CJFS-004-SB-1.03E-02 0.00E+00 0.0000 0.0000 Ni-63 9.48E+06 B1-010-04A-CJFS-004-SB8.61E-01 8.61E-01 0.0000 0.0000 Sr-90 6.59E+03 B1-010-04A-CJFS-004-SB1.20E-01 1.20E-01 0.0000 0.0005 Nb-94 2.02E+01 B1-010-04A-CJFS-004-SB2.68E-03 2.68E-03 0.0001 0.0033 T c-99 3.56E+02 B1-010-04A-CJFS-004-SB8.45E-01 8.45E-01 0.0024 0.0593 Cs-137 5.81E+01 B1-010-04A-CJFS-004-SB9.21E-03 9.21E-03 0.0002 0.0040 Eu-152 2.84E+01 B1-010-04A-CJFS-004-SB-3.22E-02 0.00E+00 0.0000 0.0000 Eu-154 2.64E+01 B1-010-04A-CJFS-004-SB8.23E-03 8.23E-03 0.0003 0.0078 Eu-155 1.12E+03 B1-010-04A-CJFS-004-SB-4.45E-03 0.00E+00 0.0000 0.0000 Np-237 7.99E-01 B1-010-04A-CJFS-004-SB2.39E-03 2.39E-03 0.0030 0.0748 P u-238 1.66E+03 B1-010-04A-CJFS-004-SB2.25E-04 2.25E-04 0.0000 0.0000 P u-239 1.49E+03 B1-010-04A-CJFS-004-SB-2.13E-02 0.00E+00 0.0000 0.0000 P u-240 1.50E+03 B1-010-04A-CJFS-004-SB-2.13E-02 0.00E+00 0.0000 0.0000 P u-241 3.64E+04 B1-010-04A-CJFS-004-SB-2.75E-01 0.00E+00 0.0000 0.0000 Am-241 1.09E+03 B1-010-04A-CJFS-004-SB1.33E-02 1.33E-02 0.0000 0.0003 Am-243 1.87E+02 B1-010-04A-CJFS-004-SB6.62E-03 6.62E-03 0.0000 0.0009 Cm-243 2.88E+02 B1-010-04A-CJFS-004-SB-6.06E-03 0.00E+00 0.0000 0.0000 Cm-244 2.67E+03 B1-010-04A-CJFS-004-SB-6.06E-03 0.00E+00 0.0000 0.0000 0.1437

Question 4:

B1-010- 004. The licensees response to RAI 3g states:

No additional remediation took place in the WGTV Basement after the continuing characterization cores were obtained. The ISOCS results from the survey reflect the expectations of the results with the cores. The highest ISOCS result, 1.32E+7 pCi/m2 was obtained from the WGTV sump, which also had the highest Cs-137 concentration of 148 pCi/g. The value of 148 pCi/g when converted to pCi/m2 is 4.42E+6 pCi/m2. The mean and median of the systemic measurements of 5.77E+4 and 3.77E+4 pCi/m2, equate to 1.94 and 1.27 pCi/g of Cs-137. This is in line with the sporadic contamination within the area and the use of a 28.3m2 field of view for the ISOCS measurements.

Please provide the assumptions and/or detailed calculations supporting these conversions from pCi/m2 to pCi/g. Please also provide additional justification as to why additional remediation did not take place in this survey unit given the results of the continuing characterization samples.

LaCrosseSolutions Response:

The calculation for converting a pCi/g analytical value to the units of pCi/m2 is as follows:

4 x pCi 1.27cm 1m2 1x104 cm2 2.35 g= pCi g m2 cm3 m2

The assumptions are that the depth of contamination is 0.5 (1.27cm) and the density of the concrete is 2.35 g/cm3. These are the same parameters as those used for the conversion presented in RS-TD-31319- 001, Radionuclides of Concern During LACBWR Decommissioning.

Additional remediation did not take place within the WGTV sump due to difficulties in decontaminating a small area and fears of fracturing the base of the sump, which would introduce groundwater intrusion into the WGTV. Additionally, at that point in the project, LACBWR did not have finalized Operational or Base Case DCGLs and the highest ISOCS measurement was below the Base Case DCGL at that time. Surface scans were also performed by NRC Region III, where an elevated area was noted by the sump, but the average was below the DCGL.

Question 5:

L1-SUB-TDS. Two of the eight continuing characterization samples in the Turbine Building Excavation were positive for Tc-99 but they contained no other radionuclides above MDC. Has the licensee calculated the relative dose contribution at this concentration for Tc-99? The average concentration of Tc-99 for soils from characterization was 0.576 pCi/g, and the staff notes that this is not far off from what was assumed to derive the IC dose contribution.

However, if the relative proportion of the radionuclides was assumed to be consistent, the staff believes these samples would also have been positive for Cs-137. Could ES provide the analysis that shows or a discussion that supports that this meets the original IC dose contribution assumptions? The staff notes that the associated RAI path forward (RAI 3) asked for detailed calculations to estimate the actual IC dose for each individual sample result.

LaCrosseSolutions Response:

The results for L1 -SUB-TDS-FJGS-004-SB and L1-SUB-TDS-FJGS-006-SB were both positive for Tc-99 with respective concentrations of 0.530 and 0.628 pCi/g, respectively. These results indicate a yearly dose of 0.0372 and 0.0441 mrem/yr, respectively due to Tc-99. The total IC dose for these samples indicate 0.0457 and 0.0662 mrem/yr, respectively. The highest IC dose was associated with L1 -SUB-TDS-FJGS-010- SB, with a value of 0.1439 mrem/yr. These values are all well below the 2.5 mrem/yr assumption for IC dose contribution for the DCGLs.

Cs-137 was detected in both samples from boththe on-site and off-site laboratories. Off-site results for samples L1-SUB-TDS-FJGS-004-SB and L1-SUB-TDS-FJGS-006-SB were 0.103 and 0.189 pCi/g, respectively. Onsite results for the same samples indicate Cs-137 concentrations of 0.0607 and 0.188 pCi/g,respectively.

The following present the calculations for the IC doses for the samples referenced above:

5 Base Case DCGL Remove Radionuclide (pCi/g) Sample Activity (pCi/g) Negative Fraction Dose IC Dose H-3 1.75E+04 L1-SUB-T DS-FJGS-004-SB -5.28E-01 0.00E+00 0.0000 0.0000 C-14 2.45E+05 L1-SUB-T DS-FJGS-004-SB -8.69E-01 0.00E+00 0.0000 0.0000 Fe-55 1.02E+07 L1-SUB-T DS-FJGS-004-SB 2.34E+00 2.34E+00 0.0000 0.0000 Ni-59 2.59E+07 L1-SUB-T DS-FJGS-004-SB -1.24E-01 0.00E+00 0.0000 0.0000 Co-60 1.28E+01 L1-SUB-T DS-FJGS-004-SB 5.96E-02 5.96E-02 0.0047 0.1163 Ni-63 9.48E+06 L1-SUB-T DS-FJGS-004-SB 1.98E-01 1.98E-01 0.0000 0.0000 Sr-90 6.59E+03 L1-SUB-T DS-FJGS-004-SB 2.29E-02 2.29E-02 0.0000 0.0001 Nb-94 2.02E+01 L1-SUB-T DS-FJGS-004-SB 6.01E-03 6.01E-03 0.0003 0.0074 T c-99 3.56E+02 L1-SUB-T DS-FJGS-004-SB 5.30E-01 5.30E-01 0.0015 0.0372 Cs-137 5.81E+01 L1-SUB-T DS-FJGS-004-SB 1.03E-01 1.03E-01 0.0018 0.0443 Eu-152 2.84E+01 L1-SUB-T DS-FJGS-004-SB 9.20E-03 9.20E-03 0.0003 0.0081 Eu-154 2.64E+01 L1-SUB-T DS-FJGS-004-SB -3.00E-04 0.00E+00 0.0000 0.0000 Eu-155 1.12E+03 L1-SUB-T DS-FJGS-004-SB -3.01E-02 0.00E+00 0.0000 0.0000 Np-237 7.99E-01 L1-SUB-T DS-FJGS-004-SB 0.00E+00 0.00E+00 0.0000 0.0000 P u-238 1.66E+03 L1-SUB-T DS-FJGS-004-SB 1.83E-02 1.83E-02 0.0000 0.0003 P u-239 1.49E+03 L1-SUB-T DS-FJGS-004-SB -1.70E-03 0.00E+00 0.0000 0.0000 P u-240 1.50E+03 L1-SUB-T DS-FJGS-004-SB -1.70E-03 0.00E+00 0.0000 0.0000 P u-241 3.64E+04 L1-SUB-T DS-FJGS-004-SB -1.09E+00 0.00E+00 0.0000 0.0000 Am-241 1.09E+03 L1-SUB-T DS-FJGS-004-SB 1.91E-02 1.91E-02 0.0000 0.0004 Am-243 1.87E+02 L1-SUB-T DS-FJGS-004-SB 2.60E-03 2.60E-03 0.0000 0.0003 Cm-243 2.88E+02 L1-SUB-T DS-FJGS-004-SB -4.50E-03 0.00E+00 0.0000 0.0000 Cm-244 2.67E+03 L1-SUB-T DS-FJGS-004-SB -4.50E-03 0.00E+00 0.0000 0.0000 0.0457

Base Case DCGL Remove Radionuclide (pCi/g) Sample Activity (pCi/g) Negative Fraction Dose IC Dose H-3 1.75E+04 L1-SUB-T DS-FJGS-006-SB 3.40E-01 3.40E-01 0.0000 0.0005 C-14 2.45E+05 L1-SUB-T DS-FJGS-006-SB -1.07E+00 0.00E+00 0.0000 0.0000 Fe-55 1.02E+07 L1-SUB-T DS-FJGS-006-SB 1.02E+00 1.02E+00 0.0000 0.0000 Ni-59 2.59E+07 L1-SUB-T DS-FJGS-006-SB -1.71E+00 0.00E+00 0.0000 0.0000 Co-60 1.28E+01 L1-SUB-T DS-FJGS-006-SB 4.34E-02 4.34E-02 0.0034 0.0847 Ni-63 9.48E+06 L1-SUB-T DS-FJGS-006-SB 7.96E-01 7.96E-01 0.0000 0.0000 Sr-90 6.59E+03 L1-SUB-T DS-FJGS-006-SB -6.57E-02 0.00E+00 0.0000 0.0000 Nb-94 2.02E+01 L1-SUB-T DS-FJGS-006-SB 5.40E-03 5.40E-03 0.0003 0.0067 T c-99 3.56E+02 L1-SUB-T DS-FJGS-006-SB 6.28E-01 6.28E-01 0.0018 0.0441 Cs-137 5.81E+01 L1-SUB-T DS-FJGS-006-SB 1.89E-01 1.89E-01 0.0033 0.0813 Eu-152 2.84E+01 L1-SUB-T DS-FJGS-006-SB 4.90E-03 4.90E-03 0.0002 0.0043 Eu-154 2.64E+01 L1-SUB-T DS-FJGS-006-SB -4.90E-03 0.00E+00 0.0000 0.0000 Eu-155 1.12E+03 L1-SUB-T DS-FJGS-006-SB 3.89E-02 3.89E-02 0.0000 0.0009 Np-237 7.99E-01 L1-SUB-T DS-FJGS-006-SB 4.00E-04 4.00E-04 0.0005 0.0125 P u-238 1.66E+03 L1-SUB-T DS-FJGS-006-SB -4.20E-03 0.00E+00 0.0000 0.0000 P u-239 1.49E+03 L1-SUB-T DS-FJGS-006-SB -1.15E-02 0.00E+00 0.0000 0.0000 P u-240 1.50E+03 L1-SUB-T DS-FJGS-006-SB -1.15E-02 0.00E+00 0.0000 0.0000 P u-241 3.64E+04 L1-SUB-T DS-FJGS-006-SB -2.80E+00 0.00E+00 0.0000 0.0000 Am-241 1.09E+03 L1-SUB-T DS-FJGS-006-SB 1.76E-02 1.76E-02 0.0000 0.0004 Am-243 1.87E+02 L1-SUB-T DS-FJGS-006-SB 9.10E-03 9.10E-03 0.0000 0.0012 Cm-243 2.88E+02 L1-SUB-T DS-FJGS-006-SB -9.50E-03 0.00E+00 0.0000 0.0000 Cm-244 2.67E+03 L1-SUB-T DS-FJGS-006-SB -9.50E-03 0.00E+00 0.0000 0.0000 0.0662

6 Base Case DCGL Remove Radionuclide (pCi/g) Sample Activity (pCi/g)NegativeFraction Dose IC Dose H-3 1.75E+04 L1-SUB-T DS-FJGS-010-SB -8.41E-01 0.00E+00 0.0000 0.0000 C-14 2.45E+05 L1-SUB-T DS-FJGS-010-SB -1.01E+00 0.00E+00 0.0000 0.0000 Fe-55 1.02E+07 L1-SUB-T DS-FJGS-010-SB 5.15E-01 5.15E-01 0.0000 0.0000 Ni-59 2.59E+07 L1-SUB-T DS-FJGS-010-SB -4.26E-01 0.00E+00 0.0000 0.0000 Co-60 1.28E+01 L1-SUB-T DS-FJGS-010-SB -3.20E-03 0.00E+00 0.0000 0.0000 Ni-63 9.48E+06 L1-SUB-T DS-FJGS-010-SB -4.08E-01 0.00E+00 0.0000 0.0000 Sr-90 6.59E+03 L1-SUB-T DS-FJGS-010-SB -5.03E-02 0.00E+00 0.0000 0.0000 Nb-94 2.02E+01 L1-SUB-T DS-FJGS-010-SB 1.14E-02 1.14E-02 0.0006 0.0141 T c-99 3.56E+02 L1-SUB-T DS-FJGS-010-SB 4.23E-01 4.23E-01 0.0012 0.0297 Cs-137 5.81E+01 L1-SUB-T DS-FJGS-010-SB 5.63E-02 5.63E-02 0.0010 0.0242 Eu-152 2.84E+01 L1-SUB-T DS-FJGS-010-SB 1.62E-02 1.62E-02 0.0006 0.0142 Eu-154 2.64E+01 L1-SUB-T DS-FJGS-010-SB 3.27E-02 3.27E-02 0.0012 0.0310 Eu-155 1.12E+03 L1-SUB-T DS-FJGS-010-SB 1.32E-02 1.32E-02 0.0000 0.0003 Np-237 7.99E-01 L1-SUB-T DS-FJGS-010-SB 3.10E-03 3.10E-03 0.0039 0.0970 P u-238 1.66E+03 L1-SUB-T DS-FJGS-010-SB -6.60E-03 0.00E+00 0.0000 0.0000 P u-239 1.49E+03 L1-SUB-T DS-FJGS-010-SB -3.03E-03 0.00E+00 0.0000 0.0000 P u-240 1.50E+03 L1-SUB-T DS-FJGS-010-SB -3.03E-03 0.00E+00 0.0000 0.0000 P u-241 3.64E+04 L1-SUB-T DS-FJGS-010-SB -3.59E-01 0.00E+00 0.0000 0.0000 Am-241 1.09E+03 L1-SUB-T DS-FJGS-010-SB -3.40E-03 0.00E+00 0.0000 0.0000 Am-243 1.87E+02 L1-SUB-T DS-FJGS-010-SB 1.75E-02 1.75E-02 0.0001 0.0023 Cm-243 2.88E+02 L1-SUB-T DS-FJGS-010-SB 5.20E-03 5.20E-03 0.0000 0.0005 Cm-244 2.67E+03 L1-SUB-T DS-FJGS-010-SB 5.20E-03 5.20E-03 0.0000 0.0000 0.1439

Question 6:

L1-SUB-TDS. ORISE conducted a confirmatory survey of the Turbine Building Excavation survey unit from January 15-18, 2018. The results of the confirmatory survey concluded that LACBWRs FSS design and implementation were appropriate and reported results were acceptable for demonstrating compliance with the release criteria given that all the radionuclide concentrations in measurements obtained in the confirmatory survey were at least an order of magnitude less than the respective Operational DCGLs.

The ORISE confirmatory survey noted that the physical boundary established by LACBWR for the turbine building excavation did not match the planned boundary established in the GIS files as indicated by the difference in where ORISE performed scans and the blue line at the southern portion of the survey unit in the associated figures. The survey also stated that the post-survey review of the gamma walkover maps showed a discrepancy between the planned survey unit boundary and the physical boundary observed in the field. Please confirm that the boundaries of the survey units surrounding the excavation survey unit of L1-SUB-TDS share physical boundaries such that 100 percent of the soil area was investigated. Please explain the difference in this survey unit boundary andconfirm that the portion of the survey unit that was not scanned by ORISE during their confirmatory survey was scanned by the licensee during FSS.

LaCrosseSolutions Response:

A review of the FSS f ield l ogs for L1- 010- 102 was performed,and it was confirmed that 100%

of L1-SUB-TDS was scanned.

7 Based on a review of release r ecords for L1-010- 102 and L1-SUB-TDS it is not apparent what caused the discrepancy in the s urvey unit boundary between the ORISE and licenseesurveys. A review of the FSS f ield l ogs for L1- 010- 102 was performed, and it was confirmed that the areas not scanned by ORISE were scanned by LaCrosse Solutions technicians.

Question 7:

L1-SUB-TDS A. Why was one continuing characterization sample in the Eastern Portion of the Turbine Building, Sump, Pit, and Diesel Excavation survey unit considered adequate? From where in the survey unit was it taken? Was it taken from the highest risk area (sump area)?

LaCrosseSolutions Response:

L1-SUB-TDS A covered a small portion of the Turbine Building, with only one location identified within the unit from the removed drain systems. Its location is in the southern portion of the unit, adjacent to L1-SUB-TDS B survey unit. The location is labeled L1-SUB-CJGS-A01 and is adjacent to sample location 15 on Figure 16-1. When taken as a whole, the TDS area had 17 continuing characterization samples taken, when taking into account TDS (8), TDS A (1), and TDS B (8). The 17 samples are considered adequate to appropriately characterize the area.

The highest risk area, the RPGPA sump, was sampled during the L1-SUB-TDS B FSS. Results of the analysis are detailed in the associated L1 -SUB-TDS B Release Record. Other sample locations for continuing characterization of the Turbine Building are associated with the suspected broken drain lines, Turbine sump, pit, and the condenser pit.

Question 8:

L1-SUB-TDS B. For the RPGPA Excavation continuing characterization samples and RASS samples, please provide the location of where the samples were taken. Provide a map with the continuing characterization and RASS sample locations (in Figure 16-1 or a new Figure 16-2).

LaCrosseSolutions Response:

The two figures below show the sample locations for the RASS performed in L1-SUB-TDS B.

8 Figure 5 - L1-SUB -TDS B RASS Sample Locations Gamma Measurements

9 Figure 6 - L1-SUB -TDS B RASS Sample Locations

10 The figure below shows the locations of the continuing characterization samples.

Figure 7 - L1-SUB -TDS B Continuing Characterization Sample Locations

11 Question 9:

L1-SUB-TDS B. The release record states that the maximum IC dose in the survey unit was 0.6373 mrem/yr, and then also states that the IC dose from Sump Area #1 is 0.4987 mrem/yr. It is confusing that the IC dose from samples with none of the insignificant radionuclides above MDC would be higher than that for Sump Area #1, which had several insignificant radionuclides above MDC. Could you please provide the detailed calculations? Was the material represented by the Sump Area #1 soil sample removed or left in place?

LaCrosseSolutions Response:

The value of 0.4987 mrem/yr is an error. The IC dose for Sump Area #1 is 0.6373 mrem/yr, and the Release Record will be revised to reflect the value. The highest IC dose for the other samples within L1 -SUB-TDS B is 0.0956 mrem/yr. The materials represented by Sump Area # 1 were remediated and shipped off-site as waste. The following is the IC calculation for the Sump Area

  1. 1 sample:

Base Case DCGL Remove Radionuclide (pCi/g) Sample Activity (pCi/g)Negative Fraction Dose IC Dose H-3 1.75E+04 Sump #1 2. 46E+00 2. 46E+00 0. 0001 0. 0035 C-14 2. 45E+05 Sump #1 4. 46E-01 4. 46E-01 0. 0000 0. 0000 Fe-55 1. 02E+07 Sump #1 -2. 63E-01 0. 00E+00 0. 0000 0. 0000 Ni-59 2. 59E+07 Sump #1 1. 70E+00 1. 70E+00 0. 0000 0. 0000 Co-60 1. 28E+01 Sump #1 1. 23E+01 1. 23E+01 0. 9602 24. 0047 Ni-63 9. 48E+06 Sump #1 1. 83E+02 1. 83E+02 0. 0000 0. 0005 Sr-90 6. 59E+03 Sump #1 4. 24E+00 4. 24E+00 0. 0006 0. 0161 Nb-94 2. 02E+01 Sump #1 1. 58E-03 1. 58E-03 0. 0001 0. 0020 T c-99 3. 56E+02 Sump #1 2. 33E+00 2. 33E+00 0. 0065 0. 1635 Cs-137 5. 81E+01 Sump #1 1. 93E+02 1. 93E+02 3. 3207 83. 0179 Eu-152 2. 84E+01 Sump #1 -3. 71E-02 0. 00E+00 0. 0000 0. 0000 Eu-154 2. 64E+01 Sump #1 5. 57E-01 5. 57E-01 0. 0211 0. 5283 Eu-155 1. 12E+03 Sump #1 9. 95E-02 9. 95E-02 0. 0001 0. 0022 Np-237 7. 99E-01 Sump #1 -4. 43E-03 0. 00E+00 0. 0000 0. 0000 P u-238 1. 66E+03 Sump #1 2. 55E+00 2. 55E+00 0. 0015 0. 0384 P u-239 1. 49E+03 Sump #1 2. 73E+00 2. 73E+00 0. 0018 0. 0457 P u-240 1. 50E+03 Sump #1 2. 73E+00 2. 73E+00 0. 0018 0. 0456 P u-241 3. 64E+04 Sump #1 4. 10E+01 4. 10E+01 0. 0011 0. 0282 Am-241 1. 09E+03 Sump #1 1. 04E+01 1. 04E+01 0. 0096 0. 2388 Am-243 1. 87E+02 Sump #1 4. 36E-01 4. 36E-01 0. 0023 0. 0584 Cm-243 2. 88E+02 Sump #1 1. 10E-01 1. 10E-01 0. 0004 0. 0095 Cm-244 2. 67E+03 Sump #1 1. 10E-01 1. 10E-01 0. 0000 0. 0010 0. 6373

Question 10:

L1-010- 101 C. Were there any continuing characterization samples taken before backfilling either prior to or during the original FSS of the Waste Treatment Building (WTB) Excavation? If so, may we have the results from those samples? How about the samples collected as part of the NRC inspection activities? Were they analyzed for any other radionuclides?

LaCrosseSolutions Response:

12 A search was performed for continuing characterization samples from the WTB excavation. Both the Chain of Custody logs and reports from GEL during the time period were searched. No additional sample shipments nor results from the off-site laboratory were found.

Question 11:

L1-SUB-DRS. For the Radiologically Controlled Area North Excavation, please explain why continuing characterization was not necessary in this survey unit. Why was the original characterization of the above land survey unit deemed adequate for this survey unit and no samples sent off for analysis for the full suite of initial radionuclides?

LaCrosseSolutions Response:

Section 2.4 of the LTP lists the areas designated for continuing characterization:

  • WGTV interior structural surfaces
  • Underlying concrete in the Reactor Building basement after liner removal
  • Soil under the Turbine Building (suspect broken drain line)
  • Soil adjacent to and beneath basement structures
  • Interior of buried pipe that may remain The L1-SUB-DRS area was not designated as a continuing characterization area in accordance with Section 2.4 of the LTP. However, anRA was performed in the Class 2 survey unit directly adjacent to L1-SUB-DRS for the sloping of the excavation. This RA was L2-SUB-103, and one sample (L2 -SUB-103-AJGS-002-SB) was sent off -site for the full suite of radionuclides. No radionuclides of concern were identified in the sample.

No continuing characterization samples or other samples analyzed for the full suite of radionuclides have prompted an adjustment to the insignificant contributor dose, and it is highly unlikely that, had samples been analyzed for the full suite of radionuclides in this survey unit, the insignificant contributor dose would change.

Question 12:

L1-SUB-LES. There were several alarms during the RASS prior to FSS of the Low Specific Activity (LSA) Building, Eat Shack, and Septic Excavation survey unit, and this area received additional remediation. The Cs -137 concentration was 29 pCi/g, and the Co-60 concentration was 85.7 pCi/g in the samples taken prior to FSS. However, there were no continuing characterization samples taken as per Section 5.3.3.4, Inaccessible or Not Readily Accessible Areas, of the LACBWR LTP. What was the process to decide that no continuing characterization samples would be collected given that this was a previously uncharacterized area?

LaCrosseSolutions Response:

Similarly, to L1 -SUB-DRS, the L1-SUB-LES area was not designated as a continuing characterization area in accordance with Section 2.4 of the LTP.

No continuing characterization samples or other samples analyzed for the full suite of radionuclides have prompted an adjustment to the insignificant contributor dose, and it is highly

13 unlikely that, had samples been analyzed for the full suite of radionuclides in this survey unit, the insignificant contributor dose would change.

Question 13:

L1-SUB-CDR. In the RPGPA Excavation survey unit, the Cs-137 value measured using gamma spectroscopy on NRC Sample #4 was 1.52 pCi/g compared to the 171 pCi/g measured in the lab.

The NRC asked for additional information on the difference between NRC Sample #4 gamma spectroscopy measurements versus the GEL Laboratory results. The licensee responded stating:

Sample NRC-CDR #4 is believed to have been split from a different sample coming from the RPGPA area, which was split from the unit due to necessary remediation. It is believed the split may have been from one of the sump samples. This is supported by the results of the concrete core sampling of the tunnel, which was the structure removed for the unit. Sample results from the concrete cores, B1008101-CJ-FC-002-CV 0-1/2, B1008101-CJ-FC-003-CV 0-1/2, and B1008101-CJ-FC-004-CV 0-1/2 were 16.0, 10.0, and 19.8 pCi/g for Cs-137. These were biased concrete core samples of the source of the remediation (concrete tunnel), which were removed and contained much less activity than NRC-CDR #4.

Please walk through the connection between these concrete core sample results and the Cs -137 concentrations in NRC Sample #4. If the NRC Sample #4 Cs-137 concentrations were really associated with the sump samples that were remediated, this needs to be explicitly stated and supported with some sort of basis. The staff notes that this was not described in the associated release record and is an important aspect of the final status survey.

As the release record reads, the NRC Sample #4 results are presented as an investigational sample with radionuclide concentrations above the DCGLs (both Operational and Base Case) that was not remediated. Please clarify if the soil associated with NRC Sample #4 was remediated and consider updating the release record to clarify this situation and the relationship of the NRC Sample #4 results to the final status of the survey unit.

LaCrosseSolutions Response:

The belief that the GEL results for NRC Sample #4 were much higher than the on-site results due to a split from one of the sump samples being sent to GEL is due to the concentration of the sample. The results of the sample, 0.0758 and 1.52 pCi/g of Co-60 and Cs-137, respectively, are consistent with the means of the L1 -SUB-CDR systematic sample population, 0.103 and 1.24 pCi/g of Co-60 and Cs-137, respectively. This indicates the sample was obtained from the excavation subjected to FSS, and not the excluded RPGPA excavation where sample results ranged from 2.86 to 18.8 pCi/g for Co-60 and 105 to 200 pCi/g for Cs-137.

A search of the gamma spectroscopy computer was performed for sample results from the time period of the surveys. A result for NRC #4 was discovered. The results of the analysis are 22.4 pCi/g for Co-60, and 210 pCi/g of Cs-137, which are consistent with the RPGPA excavation at that time. The sample date and time are identical to the sample analyzed by GEL, 09/13/2017, 1345. The sample analysis for the investigational result within the Release Record is labeled

14 CDR #4 and subsequent sample identification numbers are CDR-NRC-5 through CDR-NRC-9. These samples were all obtained on 09/15/2017.

Sample "NRC #4" is not a part of the excavation subjected to the L1-SUB-CDR FSS. Materials associated with this sample were remediated and the associated land area was subjected to FSS as survey unit L1-SUB-TDS B. The L1-SUB-CDR Release Record will be revised to change references to NRC #4 to CDR #4 and subsequent samples identified as CDR-NRC-5 through CDR-NRC-9 to remove the relationship of the NRC #4 sample results with the L1-SUB-CDR survey unit.

Question 14:

The NRCs RAI 5 stated that the release record for the WGTV Basement contains information in Table 7-4, Summary of Replicate ISOCS Measurements for QC, Section 8, and Attachment 4 on two replicate ISOCS measurements acquired during the FSS of the basement structure.

According to Attachment 4 and Section 8 of the release record, both pairs of measurements did not identify any radionuclides in the samples. The licensee stated that their acceptance method could not be utilized for this situation, and since the detectable radioactivity levels were well below the OpDCGL for basements, no further action was deemed necessary.

Based on a review of the survey data in Attachment 6 of the release record, the Cs -137 concentrations in the original and quality control (QC) samples were above the reported MDCs.

For sample B1 010- 004-QSFC GM, the values are 2.13E+05 pCi/m2 with an MDC of 4.81E+04 pCi/m2; and for sample WGTV-03, the values are 1.93E+05 pCi/m2 with an MDC of 4.72E+04 pCi/m2. For sample B1- 010- 004-QSWC GM, the values are 2.83E+04 pCi/m2 with an MDC of 2.20E+04 pCi/m2; and for sample WGTV-10, the values are 2.62E+04 pCi/m2 with an MDC of 2.38E+04 pCi/m2. Given that both the QC and original ISOCS measurements have Cs-137 concentrations above the associated MDCs, the licensee should provide the QC analysis or a discussion of why this approach is acceptable. The licensee should also explain why of the release record does not agree with the raw data, which matches the data summarized in Table 7-4 of the release record.

The RAI response states that in this case, both pairs of standard and comparison measurements contained insignificant or no detectable radioactivity, and all were well below the OpDCGLB.

However, the staff notes that there is a difference between saying there was nothing above MDA and saying it was slightly above MDA. Please provide clarification on this response.

LaCrosseSolutions Response:

The question above states, according to Attachment 4 and Section 8 of the release record, both pairs of measurements did not identify any radionuclides in the samples. Attachment 4 and Section 8 do not state that that no radionuclides were identified, rather that there were no mutually identified radionuclides, meaning that there were no common radionuclides identified between each standard / comparison pair with which to run the acceptance test.

Further, there were no radionuclides of concern identified, only insignificant radionuclides.

Thus,the statement in the release record that in this case, both pairs of standard and comparison

15 measurements contained insignificant or no detectable radioactivity is true. This statement is not intended to imply that nothing was above MDA; the only radionuclides that were identified were insignificant.

The identification of a radionuclide comes from the portion of the gamma spectroscopy report titled Interference Corrected Report. Although specific radionuclides may be s hown in the Nuclide MDA Report section as being above MDA, several algorithms and tests are taken into account within the software to show specific radionuclides as being identified in the Interference Corrected Report. Theprincipal calculation, in this case, of the algorithms and tests within the software is the identification confidence. The identification confidence must be a high enough value for a specific energy line for the software to print a specific radionuclide i n the Interference Corrected Report. Thus, it is not uncommon for radionuclides to be above MDA in the Nuclide MDA Report and not be reported as identified in the Interference Corrected Report, especially if the activity is near background.

Considering the above, the conclusions reached in the release record regarding the quality control assessment are valid.

16

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