ML21067A187

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Supplemental Information Related to the Final Status Survey Final Reports RAIs Response, Attachment 1
ML21067A187
Person / Time
Site: Zion  File:ZionSolutions icon.png
Issue date: 02/10/2021
From:
ZionSolutions
To:
Office of Nuclear Material Safety and Safeguards
Shared Package
ML21067A225 List:
References
ZS-2021-0001
Download: ML21067A187 (18)


Text

ZionSolutions ZS-2021-0001 Attachment 1 Zion Nuclear Power Station, Units 1 and 2 Supplemental Information Related to the Final Status Survey Final Reports

ZionSolutions, LLC ZS-2021-0001 Supplemental Information Related to the Final Status Survey Final Reports NRC Questions on Zion FSS Reports - October 1, 2020 Conference Call NRC Question #1 Verify that Release Record 12109 (South Half of Unit 1 Containment) contains a typo in that ORISE performed their confirmatory surveys of this area in April and July 2019 versus the incorrect date of August 2019.

RESPONSE: ZionSolutions acknowledges the correct dates that ORISE performed their confirmatory surveys in the following Power Block survey units are April and July 2019 versus the incorrect date of August 2019: 10203A, 10203F, 12201A, B and C, 12202A, B, C, D, E and F, 12104, 12105, 12106, 12107, 12108, 12109, 12110, and 12111. This response serves as an addendum to the release records listed above.

NRC Question #2 A conference call is needed to discuss the timeline on the progression of surveys done for RR 12109.

RESPONSE: During a conference call that was conducted on October 8, 2020, the NRC staff communicated a request for a timeline on the progression of surveys done for survey unit 12109.

Survey unit 12109 resides in the Power Block area. The Power Block consists of 19 Class 1 open land survey units for Final Status Survey (FSS).

January to February 2019 - Initial remediation of soils at the 588 ft. elevation in the Power Block (including 12109).

February to April 2019 - Post remediation scanning and sampling of soils in the Power Block (including 12109). Excavations were not backfilled to allow for confirmatory survey.

April 15, 2019 - ORISE begins confirmatory survey of Power Block.

April 16, 2019 - Survey identifies particle in survey unit 12106.

April 17, 2019 - Survey identifies a second particle in survey unit 12106. Upon discovery of the second particle, ZSRP Project Management requested that the in-progress confirmatory survey by ORISE be suspended so that ZSRP could investigate.

April 18, 2019 - Commenced resurvey of Power Block soils at the 588 ft. elevation.

May 20, 2019 - Completed initial resurvey of Power Block soils (including 12109).

May 20, 2019 - A readiness walk-down was performed of the Power Block. Participants included the D&D Manager, D&D Projects Manager, Lead C/LT Engineer, C/LT Supervisor, and the Director Radiological Site Closure.

May 28, 2019 - completed resurvey of Power Block soils at the 588 ft. elevation (including 12109).

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ZionSolutions, LLC ZS-2021-0001 Supplemental Information Related to the Final Status Survey Final Reports June 18, 2019 - A readiness report regarding this event in the Power Block was issued to the Site Manager. Upon submittal, the NRC was contacted pertaining to the resumption of the confirmatory survey of the Power Block.

July 15-19, 2019 - ORISE completed the confirmatory survey of the Power Block. Upon completion of the surveys, ZSRP backfilled all excavations and imported clean fill to the site to raise the elevation of the Power Block soils from the 588 ft. elevation to the 591 ft.

elevation as required by the LTP.

September 4, 2019 - Performed FSS of survey unit 12109.

Supplemental or Revised Documentation: Power Block RA Report Attachments and Power Block RA Readiness Review NRC Question #3 A call is needed to discuss Release Record 10221B (Near railroad)

RESPONSE: During a conference call that was conducted on October 8, 2020, the NRC staff communicated a request for clarification of the timing of FSS versus an RA performed in survey unit 10221B. The release record for the FSS of survey unit 10221B states the following, An investigation was performed based on the results of gamma scans performed under an RA on June 17, 2019 on the railroad ballast located in survey unit 10221B and the soil areas 1-meter beyond the ballast gravel (these scans were performed subsequent to the scans performed under the FSS Sample Plan). ZionSolutions has revised the release record for survey unit 10221B to clarify that the RA performed on the railroad ballast (which covered numerous survey units) was performed at the same time as the FSS of 10221B.

On May 14, 2019, FSS was performed of survey unit 10221D. An elevated area was identified directly adjacent to the railroad ballast supporting the rail line that transited through the southern portion of the survey unit. The railroad ballast is comprised of large granite rocks and gravel, making it difficult to acquire a volumetric sample, and as sampling was not possible, decisions regarding potential radiological contamination could only be made by scanning. Please note that the identified elevated area in survey unit 10221D was found to be from soil contamination that was remediated and not from contaminated ballast. However, while investigating the elevated area in survey unit 10221D, inquiries were made with the railroad pertaining to the potential need to remediate the ballast. ZionSolutions was informed by the railroad that any physical movement and/or removal of the ballast could potentially undermine the structural stability of the rail line and, that the railroad must be on-site to observe the remediation and recertify the stability of the rail line before it was used again. Therefore, in order to assess the potential involvement of the railroad and to coordinate their potential presence on-site, project management directed that the ballast for the entire rail line be assessed by scanning to estimate the potential scope of any necessary remediation.

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ZionSolutions, LLC ZS-2021-0001 Supplemental Information Related to the Final Status Survey Final Reports The FSS of survey unit 10221B commenced on June 7, 2019. The scans of the entire rail line commenced under the RA on June 17, 2019, while the FSS in survey unit 10221B was still in progress, and were considered as additional judgmental scans. Even though the ballast is not considered a soil, the RA scans were performed using a scan MDC sufficient for detecting the OpDCGLs for surface soils and the scan alarm was set to the instrument MDCR plus background. The ballast RA survey documentation (Ballast RA Attachments) is provided on the enclosure to this response.

Elevated areas were identified by the scan of the ballast not only in survey unit 10221B. The areas were investigated, and the contamination was discovered in small soil footprints, adjacent to the ballast, which were spot remediated and resurveyed during FSS.

ZionSolutions has revised the following sections of the release record for 10221B to clarify the timeline as described above.

The Executive Summary, Survey Implementation, and Survey Results sections previously stated, However, subsequent scans were performed under a Radiological Assessment (RA) survey on June 17, 2019 on the railroad ballast located in survey unit 10221B and on the soil areas one-meter beyond the ballast gravel. The RA survey identified two (2) small areas of elevated activity (see Section 9 for further discussion).

ZionSolutions revised as follows: While FSS was in progress, scans were performed on the entire rail line to ascertain if it was necessary to remediate any ballast, which could potentially impact the structural integrity of the rail line. The additional scans identified two (2) small areas of elevated activity in the soils bordering the ballast (see Section 9 for further discussion).

The Survey Implementation section previously stated, While performing a gamma scan of the railroad ballast located in survey unit 10221B, and the soil areas one-meter beyond the ballast gravel, two (2) small areas of elevated activity were identified (these scans were performed subsequent to the scans performed under the FSS Sample Plan).

ZionSolutions revised as follows: While performing a gamma scan of the railroad ballast located in survey unit 10221B, and the soil areas one-meter beyond the ballast gravel, two (2) small areas of elevated activity were identified (these scans were additional judgmental scans from performing an RA of the rail line ballast at the same time as FSS).

The Investigations and Results section previously stated, An investigation was performed based on the results of gamma scans performed under an RA on June 17, 2019 on the railroad ballast located in survey unit 10221B and the soil areas 1-meter beyond the ballast gravel (these scans were performed subsequent to the scans performed under the FSS Sample Plan). The RA identified two (2) small areas of elevated activity, both less than 100 cm2, reading 3,200 cpm and 4,700 cpm (a map of these areas is included in Page 3 of 17

ZionSolutions, LLC ZS-2021-0001 Supplemental Information Related to the Final Status Survey Final Reports Attachment 1). ZionSolutions revised as follows, While FSS was in progress, scans were performed on June 17, 2019 of the entire rail line to ascertain if it was necessary to remediate any ballast, which could potentially impact the structural integrity of the rail line. The additional scans identified two (2) small areas of elevated activity, the first reading 3,200 cpm and the second reading 4,700 cpm with an area for both less than 100 cm2, in the soils bordering the ballast in survey unit 10221B, prompting an investigation.

Supplemental or Revised Documentation: Revised Release Record 10221B, Ballast RA Attachments NRC Question #4 Survey 10220F (Near ISFSI) - There was a hot particle found in this area when removing buried pipe in June 2018. Which survey unit contained the hot particle? Was it found before or after the pipe removal?

RESPONSE: The particle was discovered during the performance of an RA in support of the removal of buried pipe in Class 3 survey unit 10220B. The particle was discovered during the scan of the top-side excavation footprint, prior to excavation, for the removal of a non-contaminated buried pipe system. As a result, the particle was remediated prior to the excavation, and as a corrective action for the discovery of the particle, the single Class 3 survey unit was subsequently divided into five Class 1 survey units (10220B, 10220D, 10220E, 10220F, and 10220G). After division of survey unit 10220B into five survey units, the particle would have been within the boundaries of survey unit 10220G.

NRC Question #5 Buried Pipes - Need a cross reference table for buried pipe survey units. It is hard to correlate with the open land survey units above the buried pipe.

RESPONSE: The open land survey units where each of these buried pipes are physically located is provided in the table below.

Buried Pipe Survey Units Survey Pipe Open Land Name Class Area (ft) Survey Units Unit ID Condensate Feed Water Supply T-103, T-105, and 12205C 00101A 3 2,455 and Recirculation Buried Pipe T-106 Primary Water Supply Header T-095 and T-102 12205B 00101B 2 308 T-095 and T-102 Buried Pipe Diesel Generator Heat Exchangers AO-27, AO-28, 12104, 12109 00101F Service Water Supply and Service 3 956 AO-30, AO-31, Water Return Buried Pipe TO-32, and TO-33 Service Water Supply Header CO-26 and CO-29 12205C 00101H 3 5,248 CO-26 and CO-29 Buried Pipe 00150A/B North End Storm Drain Buried NA 10214D, 10213A, 2 2,187

&C Piping 10212D Page 4 of 17

ZionSolutions, LLC ZS-2021-0001 Supplemental Information Related to the Final Status Survey Final Reports NRC Question #6 North Yard Storm Drain - Need Eberline sample ID # for the sediment sample.

RESPONSE: The sediment sample (L2-10214C-RJGS-001-SM) was collected from the west access point during the performance of an FSS surveillance. Both Cs-137 and Co-60 were positively detected at concentrations of 2.22E+00 pCi/g and 1.80E-01 pCi/g, respectively, by the on-site gamma spectroscopy system.

In response to a previous RAI pertaining to this sample, ZionSolutions recovered the sediment sample from the archives and sent the sample for full isotopic analysis. The Eberline lab ID is 20-04072-10. This sample report was provided in Attachment 3 of the ZionSolutions response to the Phase 2 Part 2 RAI submitted in May 2020. ZionSolutions has provided another copy of the gamma spectroscopy report on the enclosure to this response.

Supplemental or Revised Documentation: Gamma Spectroscopy Report for L2-10214C-RJGS-001-SM NRC Question #7 North Yard Storm Drain - When was the NRC notified when ZionSolutions found contamination in the storm drain pipes? Provide a copy of the email or correspondence. Alternative may be the CR package. The licensee should provide additional information on the on-site source of the residual radioactivity that contaminated the drain system.

Also, the licensee should state whether additional on-site storm drain systems were investigated for similar contamination of were removed from the site.

RESPONSE: ZionSolutions notified NRC Region III Inspectors in June 2019 (via phone call) of the storm drain piping reclassification. In response, the Inspectors made a site visit to discuss the issue. In addition, a CR was generated (ES-ZION-CR-2019-0165). CR-2019-0165 is included on the enclosure to this response.

The surveillance that was performed in June 2019 that identified the residual radioactivity in the manhole for the North Yard Storm Drain was in response to a flooding incident that completely flooded the site from inside of the fenced area north of Unit 2 Containment into survey units 10212 and 10213 and into the parking lot (10214). The concern was for potential cross contamination of soils due to carryover of sediment from inside the fenced controlled area. The area (parking lot, manways, etc.) was subjected to a surveillance following the incident to assess the radiological impact of this event. A timeline depicting all the events in 10212, 10213, and 10214 leading up to the completion of FSS is provided on the enclosure to this response. As shown in the timeline, in March and November of 2019, particles were discovered in 10214. The response to RAI Question #11b provides discussion on the source and spread of particles discovered on-site.

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ZionSolutions, LLC ZS-2021-0001 Supplemental Information Related to the Final Status Survey Final Reports The investigation of other buried pipe systems is addressed in the Response to Additional NRC Question #6.

Revised or Supplemental Documentation: CR-2019-0165, Drainage Ditch Flood Timeline Page 6 of 17

ZionSolutions, LLC ZS-2021-0001 Supplemental Information Related to the Final Status Survey Final Reports Additional NRC Questions on Zion FSS Reports -October 8, 2020 Conference Call Additional NRC Question #1 Verify when ORISE survey was performed for 12109.

RESPONSE: Upon review of C/LT schedule and logs, it was determined that ORISE was physically on-site at Zion to complete the confirmatory survey of the Power Block remediated soils from July 15, 2019, to July 19, 2019.

Additional NRC Question #2 Review Phase 2 Part 1 Release Records for how replicate QC ISOCS measurements were assessed, discuss why we are in compliance with the QAPP and check for consistency in use of the resolution table from NRC Inspection Procedure No. 84750.

(specifically reference QAPP sections 4.1.1 and 4.1.2 and 6.2.2.1 - uncertainty).

RESPONSE: The Phase 2 Part 1 release records were reviewed for how replicate QC ISOCS measurements were assessed. The ISOCS was used during FSS to demonstrate compliance with the structural release criteria in 18 Phase 2 Part 1 release records. While an ISOCS measurement is basically a timed static measurement, it also assesses the volumetric residual radioactivity concentrations in the media measured. Therefore, ISOCS replicate measurements collected for QC comparison are addressed similarly to duplicate and split samples in QAPP Section 4.2 and LTP Section 5.9.3.2. Both sections state that NRC Inspection Procedure, No. 84750, Radioactive Waste Treatment, and Effluent and Environmental Monitoring is used to determine the acceptability of split and duplicate sample analyses. QAPP Sections 4.1.1 and 4.1.2 are not applicable to the QC assessment of ISOCS measurements. In addition, LTP Section 5.9.3.2 also states, Agreement is ultimately determined when the same conclusion is reached for each compared result. If the split sample or duplicate sample results do not agree, then further evaluations will be performed. This conclusion is interpreted, for the QC assessments of the ZSRP FSS, as both the standard and comparison sample or measurement activities being above or below the OpDCGL (i.e., the same dose conclusion is reached). As part of the review for this response, an ISOCS QC summary table was compiled (ISOCS QC Comparison Review below). An additional tool of +/-20% was utilized in this summary table as a check, but this tool was not documented in the release records for the survey units that utilized ISOCS for FSS.

The most current revision of ZS-LT-01, Quality Assurance Project Plan (QAPP) for Characterization and FSS is Revision 7, dated 09/24/19. The QAPP references NRC Inspection Procedure No. 84750, Radioactive Waste Treatment, and Effluent and Environmental Monitoring - March 1994. The resolution table presented in Table 4-1 of the QAPP matches the resolution table presented in the current version of Inspection Procedure No. 84750.

A review of the Replicate Measurement Assessment forms found in the Attachments for the Phase 2 Part 1 release records where the ISOCS was used to demonstrate compliance found that Page 7 of 17

ZionSolutions, LLC ZS-2021-0001 Supplemental Information Related to the Final Status Survey Final Reports the resolution table presented in the current version of Inspection Procedure No. 84750 was used in 13 of the 18 release records. The now obsolete resolution table from the previous revision of the QAPP (which had an acceptance range for resolutions less than 4) was used on the Replicate Measurement Assessment forms in the release records for survey units 03202, 06107, 06108, 06201, and 06202. For comparisons that had resolutions less than 4 when comparing Cs-137, the comparison was then made using K-40. If the resolution in the comparison using K-40 was less than 4, then agreement was determined by comparing the standard and comparison measurement activities to the OpDCGL. Agreement was ultimately determined when the same dose conclusion was reached.

Each gamma spectroscopy report is validated by a Radiological Engineer in accordance with Section 5.1 of procedure ZS-LT-300-001-004, Final Status Survey Data Assessment. The procedure addresses the required content from QAPP Section 6.2.2.1, including the verification of the absence of anomalies in the sample or measurement results, or in the supporting data, including but not limited to MDC, uncertainty, deviation from established procedure, or analysis flags.

In the 18 Phase 2 Part 1 release records where the ISOCS was used to demonstrate compliance, 73 QC replicate measurements were taken:

Of the 73 QC replicate measurements taken, 37 QC replicate measurements demonstrated adequate agreement, based on Cs-137 activity, using Procedure No. 84750.

In 22 of the 73 measurements, the Cs-137 activity in either the standard or replicate measurement was less than MDC, or the resolution of the standard measurement for Cs-137 was less than 4. As Cs-137 was no longer comparable, K-40 activity was substituted for Cs-137. Acceptable agreement was reached during the comparison of the standard and replicate measurement, based on K-40 activity, in accordance with Procedure No. 84750.

In 14 of the 73 measurements, acceptable agreement using the acceptance criteria specified in Procedure No. 84750 was not achieved. In 12 of the 14 measurements, the reason for unacceptable agreement was due to resolutions less than 4 while assessing K-40 activity. In the other 2 measurements, the comparison ratio for K-40 fell outside of the acceptable range for the observed resolution of the standard measurement. In these cases, agreement was determined by comparing the standard and comparison measurement activities to the OpDCGL. Agreement was ultimately determined when the same dose conclusion was reached.

The results of the review of the QC measurements collected using the ISOCS that was requested are provided in the following table. Due to rounding errors, the values provided in the table below may deviate slightly from the values provided in the applicable release records.

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ZionSolutions, LLC ZS-2021-0001 Supplemental Information Related to the Final Status Survey Final Reports ISOCS QC COMPARISON REVIEW Acceptable Replicate Within Range of SU # Measurement OpSOF for Cs-137 ROC Activity Value Standard Error MDC Resolution >MDC Agreement Range Sample ID Activity Value Standard Error MDC Comparison Ratio >MDC Agreement +20% -20% Measurement +20%

Sample ID Activity Standard Replicate (Y/N) Activity (Yes or no) 01100 Called replicate measurements in Release Record text, Used most current 84750 table (no <4 category), two measurements with resolution <4, replaced Cs-137 with K-40, still no agreement for those two measurements SWM-036-GD Cs-137 2.34E+05 3.72E+04 1.75E+04 6.29 Yes 0.5 - 2.0 QWM-036-GD 2.46E+05 3.77E+04 8.65E+03 1.05 Yes Y 2.34E+05 2.81E+05 1.87E+05 2.46E+05 Yes 0.028 0.030 SWM-089-GD Cs-137 3.06E+05 4.59E+04 1.88E+04 6.67 Yes 0.5 - 2.0 QWM-089-GD 3.00E+05 4.57E+04 2.16E+04 0.98 Yes Y 3.06E+05 3.67E+05 2.45E+05 3.00E+05 Yes 0.037 0.036 SFM-100-GD Cs-137 2.82E+05 4.29E+04 1.78E+04 6.57 Yes 0.5 - 2.0 QFM-100-GD 2.70E+05 4.08E+04 1.15E+04 0.96 Yes Y 2.82E+05 3.38E+05 2.26E+05 2.70E+05 Yes 0.034 0.033 SFM-124-GD Cs-137 9.43E+04 2.07E+04 1.78E+04 4.56 Yes 0.5 - 2.0 QFM-124-GD 7.59E+04 1.64E+04 9.53E+03 0.80 Yes Y 9.43E+04 1.13E+05 7.54E+04 7.59E+04 Yes 0.011 0.009 SFM-125-GD Cs-137 2.62E+05 4.20E+04 2.56E+04 6.24 Yes 0.5 - 2.0 QFM-125-GD 2.76E+05 4.45E+04 2.97E+04 1.05 Yes Y 2.62E+05 3.14E+05 2.10E+05 2.76E+05 Yes 0.032 0.033 SFM-143-GD Cs-137 1.08E+05 2.24E+04 1.84E+04 4.82 Yes 0.5 - 2.0 QFM-143-GD 9.35E+04 2.11E+04 1.94E+04 0.87 Yes Y 1.08E+05 1.30E+05 8.64E+04 9.35E+04 Yes 0.013 0.011 Cs-137 1.98E+04 1.20E+04 1.75E+04 1.65 Yes N/A 2.15E+04 1.32E+04 1.95E+04 N/A Yes N 1.98E+04 2.38E+04 1.58E+04 2.15E+04 Yes 0.002 0.003 SFM-146-GD K-40 7.40E+05 1.77E+05 t 1.65E+05 t 4.18 Yes t 0.5 - 2.0 QFM-146-GD 4.87E+06 t 1.08E+06 1.65E+05 t 6.58 t Yes N t 7.40E+05 8.88E+05 5.92E+05 t 4.87E+06 No t N/A t N/A The original comparison of Cs-137 concentrations was listed as acceptable even though the resolution was unacceptable (<4). Comparisons were also made using the K-40 concentrations. Pre and post use operational checks of the ISOCS did not indicate any issues with the instrument or the quality of the data. In addition, other replicate measurements taken at several other locations were in agreement. The concentrations for Cs-137 in the standard and replicate measurements are with +20% and the Cs-137 data produces the same dose conclusion. No further action is necessary.

Cs-137 3.46E+04 1.25E+04 1.48E+04 2.77 Yes N/A 2.00E+04 7.32E+03 6.88E+03 N/A Yes N 3.46E+04 4.15E+04 2.77E+04 2.00E+04 No 0.004 0.002 SFM-150-GD K-40 7.72E+05 1.74E+05 t 1.46E+05 t 4.44 Yes t 0.5 - 2.0 QFM-150-GD 3.80E+05 t 1.17E+05 1.46E+05 t 0.49 t Yes N t 7.72E+05 9.26E+05 6.18E+05 t 3.80E+05 No t N/A t The original comparison of Cs-137 concentrations was listed as acceptable even though the resolution was unacceptable (<4). Comparisons were also made using the K-40 concentrations. Pre and post use operational checks of the ISOCS did not indicate any issues with the instrument or the quality of the data. In addition, other replicate measurements taken at several other locations were in agreement. The standard N/A concentration for Cs-137 is 42% of the replicate and the Cs-137 data produces the same dose conclusion. No further action is necessary.

SFM-153-GD Cs-137 2.41E+05 3.71E+04 1.84E+04 6.50 Yes 0.5 - 2.0 QFM-153-GD 2.30E+05 3.68E+04 2.31E+04 0.95 Yes Y 2.41E+05 2.89E+05 1.93E+05 2.30E+05 Yes 0.029 0.028 Acceptable Replicate Within Range of SU # Measurement OpSOF for Cs-137 ROC Activity Value Standard Error MDC Resolution >MDC Agreement Range Sample ID Activity Value Standard Error MDC Comparison Ratio >MDC Agreement +20% -20% Measurement +20%

Sample ID Activity Standard Replicate (Y/N) Activity (Yes or no) 01110 Called replicate measurements in Release Record text, Used most current 84750 table (no <4 category), one measurement with resolution <4, replaced Cs-137 with K-40, in agreement SFC-006-GD Cs-137 7.88E+06 9.68E+05 8.14 Yes 0.6 - 1.66 QFC-006-GD 7.60E+06 9.35E+05 8.56E+04 0.96 Yes Y 7.88E+06 9.46E+06 6.30E+06 7.60E+06 Yes 0.956 0.922 Cs-137 3.98E+05 1.19E+05 1.67E+05 3.34 Yes N/A 4.95E+05 1.56E+05 2.26E+05 N/A Yes N 3.98E+05 4.78E+05 3.18E+05 4.95E+05 No 0.048 0.060 SWC-016-GD K-40 2.82E+06 5.09E+05 t 4.39E+05 t 5.54 Yes t 0.5 - 2.0 QWC-016-GD 2.58E+06 t 4.92E+05 4.40E+05 t 0.91 t Yes Y t 2.82E+06 3.38E+06 2.26E+06 t 2.58E+06 The resolution when using Cs-137 was unacceptable (<4). Comparison was then made using K-40. There was acceptable agreement between the standard measurement and the replicate measurement when using K-40. In addition, the standard concentration for Cs-137 is 24% of the replicate and the Cs-137 data produces the same dose conclusion. No further action is necessary.

Yes t N/A t N/A SWC-051-GD Cs-137 2.06E+06 2.71E+05 6.11E+05 7.60 Yes 0.6 - 1.66 QWC-051-GD 2.12E+06 2.83E+05 1.16E+05 0.97 Yes Y 2.06E+06 2.47E+06 1.65E+06 2.12E+06 Yes 0.250 0.257 Acceptable Replicate Within Range of SU # Measurement OpSOF for Cs-137 ROC Activity Value Standard Error MDC Resolution >MDC Agreement Range Sample ID Activity Value Standard Error MDC Comparison Ratio >MDC Agreement +20% -20% Measurement +20%

Sample ID Activity Standard Replicate (Y/N) Activity (Yes or no) 02100 Called replicate measurements in Release Record text, Used most current 84750 table (no <4 category), nine measurements with resolution <4, replaced Cs-137 with K-40, K-40 out of resolution range in three of the nine Cs-137 1.67E+04 1.07E+04 1.56E+04 1.56 Yes N/A 2.58E+04 1.03E+04 1.20E+04 N/A Yes N 1.67E+04 2.00E+04 1.34E+04 2.58E+04 No 0.002 0.003 SWM-045-GD K-40 6.39E+05 1.53E+05 t 1.17E+05 t 4.18 Yes t 0.5 - 2.0 QWM-045-GD 5.94E+05 t 1.50E+05 1.28E+05 t 0.93 t Yes Y t 6.39E+05 7.67E+05 5.11E+05 t 5.94E+05 The resolution when using Cs-137 was unacceptable (<4). Comparison was then made using K-40. There was acceptable agreement between the standard measurement and the replicate measurement when using K-40. In addition, the standard concentration for Cs-137 is 54% of the replicate and the Cs-137 data produces the same dose conclusion. No further action is necessary.

Yes t N/A t N/A Cs-137 1.97E+04 9.31E+03 1.17E+04 2.12 Yes N/A 2.18E+04 9.40E+03 2.51E+04 1.11 No N 1.97E+04 2.36E+04 1.58E+04 2.18E+04 Yes 0.002 0.003 SWM-050-GD K-40 6.45E+05 1.50E+05 t 1.03E+05 t 4.30 Yes t 0.5 - 2.0 QWM-050-GD 5.48E+05 t 1.59E+05 1.73E+05 t 0.85 t Yes Y t 6.45E+05 7.74E+05 5.16E+05 t 5.48E+05 The resolution when using Cs-137 was unacceptable (<4). Comparison was then made using K-40. There was acceptable agreement between the standard measurement and the replicate measurement when using K-40. In addition, the standard concentration for Cs-137 is within +20% of the replicate and the Cs-137 data produces the same dose conclusion. No further action is necessary.

Yes t N/A t N/A Cs-137 4.01E+04 1.34E+04 1.53E+04 2.99 Yes N/A 3.66E+04 1.40E+04 1.77E+04 N/A Yes N 4.01E+04 4.81E+04 3.21E+04 3.66E+04 Yes 0.005 0.004 SWM-060-GD K-40 5.59E+05 1.48E+05 t 1.36E+05 t 3.78 Yes t N/A QWM-060-GD 5.60E+05 t 1.44E+05 1.20E+05 t N/A t Yes N t 5.59E+05 6.71E+05 4.47E+05 t 5.60E+05 Yes t N/A t N/A The resolution when using Cs-137 was unacceptable (<4). Comparison was then made using K-40. The resolution when using K-40 was also unacceptable (<4). Pre and post use operational checks of the ISOCS did not indicate any issues with the instrument or the quality of the data. In addition, other replicate measurements taken at several other locations were in agreement. The concentrations for Cs-137 and K-40 in the standard and replicate measurements are with +20% and the Cs-137 data produces the same dose conclusion. No further action is necessary.

Cs-137 3.64E+04 1.20E+04 1.26E+04 3.03 Yes N/A 2.41E+04 1.20E+04 1.66E+04 N/A Yes N 3.64E+04 4.37E+04 2.91E+04 2.41E+04 No 0.004 0.003 SFM-100-GD K-40 6.79E+05 ~ 1.54E+05

>-The resolution when~using Cs-137 was unacceptable t 1.03E+05 t 4.41 ~

Yes t 0.5 - 2.0 ~

QFM-100-GD

~

5.45E+05 t 1.47E+05 ~ 1.38E+05 t 0.80 t Yes ~

Y t 6.79E+05 ~ 8.15E+05 ~ 5.43E+05 t 5.45E+05 ~

(<4). Comparison was then made using K-40. There was acceptable agreement between the standard measurement and the replicate measurement when using K-40. In addition, the standard concentration for Cs-137 is 34% of the replicate and the Cs-137 data produces the same dose conclusion. No further action is necessary.

Yes t N/A t N/A Cs-137 4.11E+04 2.64E+04 4.11E+04 1.56 No N/A 4.17E+04 1.38E+04 1.59E+04 N/A Yes N 4.11E+04 4.93E+04 3.29E+04 4.17E+04 Yes 0.005 0.005 SFM-115-GD K-40 7.37E+05 1.57E+05 t 8.00E+04 t 4.69 Yes t 0.5 - 2.0 QFM-115-GD 6.10E+05 t 1.48E+05 1.12E+05 t 0.83 t Yes Y t 7.37E+05 8.84E+05 5.90E+05 t 6.10E+05 The resolution when using Cs-137 was unacceptable (<4). Comparison was then made using K-40. There was acceptable agreement between the standard measurement and the replicate measurement when using K-40. In addition, the standard concentration for Cs-137 is within +20% of the replicate and the Cs-137 data produces the same dose conclusion. No further action is necessary.

Yes t N/A t N/A Cs-137 2.82E+04 1.12E+04 1.35E+04 2.52 Yes N/A 3.20E+04 1.20E+04 1.42E+04 N/A Yes N 2.82E+04 3.38E+04 2.26E+04 3.20E+04 Yes 0.003 0.004 SFM-119-GD K-40 6.48E+05 1.55E+05 t 1.24E+05 t 4.18 Yes t 0.5 - 2.0 QFM-119-GD 6.49E+05 t 1.68E+05 1.67E+05 t 1.00 t Yes Y t 6.48E+05 7.78E+05 5.18E+05 t 6.49E+05 The resolution when using Cs-137 was unacceptable (<4). Comparison was then made using K-40. There was acceptable agreement between the standard measurement and the replicate measurement when using K-40. In addition, the standard concentration for Cs-137 is within +20% of the replicate and the Cs-137 data produces the same dose conclusion. No further action is necessary.

Yes t N/A t N/A Cs-137 9.20E+04 2.33E+04 2.60E+04 3.95 Yes N/A 9.53E+04 2.29E+04 2.42E+04 N/A Yes N 9.20E+04 1.10E+05 7.36E+04 9.53E+04 Yes 0.011 0.012 SFM-139-GD K-40 5.75E+05 1.51E+05 t 1.40E+05 t 3.81 Yes t N/A QFM-139-GD 6.06E+05 t 1.56E+05 1.45E+05 t N/A t Yes N t 5.75E+05 6.90E+05 4.60E+05 t 6.06E+05 Yes t N/A t N/A The resolution when using Cs-137 was unacceptable (<4). Comparison was then made using K-40. The resolution when using K-40 was also unacceptable (<4). Pre and post use operational checks of the ISOCS did not indicate any issues with the instrument or the quality of the data. In addition, other replicate measurements taken at several other locations were in agreement. The concentrations for Cs-137 and K-40 in the standard and replicate measurements are with +20% and the Cs-137 data produces the same dose conclusion. No further action is necessary.

Cs-137 4.66E+04 1.20E+04 2.55E+04 3.88 Yes N/A 3.21E+04 1.12E+04 1.18E+04 N/A Yes N 4.66E+04 5.59E+04 3.73E+04 3.21E+04 No 0.006 0.004 SFM-150-GD K-40 6.74E+05 1.61E+05 t 1.37E+05 t 4.19 Yes t 0.5 - 2.0 QFM-150-GD 5.61E+05 t 1.57E+05 1.62E+05 t 0.83 t Yes Y t 6.74E+05 8.09E+05 5.39E+05 t 5.61E+05 The resolution when using Cs-137 was unacceptable (<4). Comparison was then made using K-40. There was acceptable agreement between the standard measurement and the replicate measurement when using K-40. In addition, the standard concentration for Cs-137 is 31% of the replicate and the Cs-137 data produces the same dose conclusion. No further action is necessary.

Yes t N/A t N/A Cs-137 2.55E+04 9.90E+03 1.11E+04 2.58 Yes N/A 1.27E+04 8.05E+03 1.12E+04 N/A Yes N 2.55E+04 3.06E+04 2.04E+04 1.27E+04 No 0.003 0.002 SFM-165-GD K-40 5.93E+05 1.51E+05 t 1.32E+05 t 3.93 Yes t N/A QFM-165-GD 6.48E+05 t 1.52E+05 1.10E+05 t N/A t Yes N t 5.93E+05 7.12E+05 4.74E+05 t 6.48E+05 Yes t N/A t N/A The resolution when using Cs-137 was unacceptable (<4). Comparison was then made using K-40. The resolution when using K-40 was also unacceptable (<4). Pre and post use operational checks of the ISOCS did not indicate any issues with the instrument or the quality of the data. In addition, other replicate measurements taken at several other locations were in agreement. The concentrations for Cs-137 in the standard and replicate measurements are with +50% and the Cs-137 data produces the same dose conclusion. No further action is necessary.

Page 9 of 17

ZionSolutions, LLC ZS-2021-0001 Supplemental Information Related to the Final Status Survey Final Reports ISOCS QC COMPARISON REVIEW (continued)

Acceptable Replicate Within Range of SU # Measurement OpSOF for Cs-137 ROC Activity Value Standard Error MDC Resolution >MDC Agreement Range Sample ID Activity Value Standard Error MDC Comparison Ratio >MDC Agreement +20% -20% Measurement -+20%

Sample ID Activity Standard Replicate (Y/N) Activity (Yes or no) 02110 Called replicate measurements in Release Record text, Used most current 84750 table (no <4 category), one measurement with resolution <4, replaced Cs-137 with K-40, in agreement SWC-016-GD Cs-137 8.43E+05 1.94E+05 2.54E+05 4.35 Yes 0.5 - 2.0 QWC-016-GD 5.65E+05 1.73E+05 2.49E+05 0.67 Yes Y 8.43E+05 1.01E+06 6.74E+05 5.65E+05 No 0.102 0.069 SWC-017-GD Cs-137 4.14E+06 5.37E+05 2.43E+05 7.71 Yes 0.6 - 1.66 QWC-017-GD 4.17E+06 5.40E+05 2.93E+05 1.01 Yes Y 4.14E+06 4.97E+06 3.31E+06 4.17E+06 Yes 0.502 0.506 Cs-137 2.44E+05 6.37E+04 7.67E+04 3.83 Yes N/A 2.50E+05 6.79E+04 8.49E+04 N/A Yes N 2.44E+05 2.93E+05 1.95E+05 2.50E+05 Yes 0.030 0.030 SWC-051-GD K-40 1.52E+06 3.77E+05 3.99E+05 4.03 Yes 0.5 - 2.0 iQWC-051-GD t 1.84E+06 t 4.02E+05 3.81E+05 t 1.21 t Yes The resolution when using Cs-137 was unacceptable (<4). Comparison was then made using K-40. There was acceptable agreement between the standard measurement and the replicate measurement when using K-40. In addition, the standard concentration for Cs-137 is +20%

Y of the 1.52E+06 replicate and the Cs-137 1.82E+06 data produces the 1.22E+06 same dose conclusion.

1.84E+06 No further action is No necessary.

N/A N/A Acceptable Replicate Within Range of SU # Measurement OpSOF for Cs-137 ROC Activity Value Standard Error MDC Resolution >MDC Agreement Range Sample ID Activity Value Standard Error MDC Comparison Ratio >MDC Agreement +20% -20% Measurement -+20%

Sample ID Activity Standard Replicate (Y/N) Activity (Yes or no) 03202 Called replicate measurements in Release Record text, Used incorrect resolution Table from 84750 (<4 category listed), one measurement with resolution <4, replaced Cs-137 with K-40, in agreement SWC-004-GD Cs-137 1.14E+06 1.48E+05 2.99E+04 7.70 Yes 0.6-1.66 IQWC-004-GD I 1.06E+06 I 1.38E+05 3.24E+04 0.93 Yes Y 1.14E+06 1.37E+06 9.12E+05 1.06E+06 Yes 0.138 0.129 Cs-137 1.07E+06 2.18E+04 1.45E+04 49.08 Yes 0.75-1.33 8.99E+04 2.03E+04 1.70E+04 0.08 Yes N 1.07E+06 1.28E+06 8.56E+05 8.99E+04 No 0.130 0.011 SWC-012-GD K-40 9.68E+05 2.03E+05 1.62E+05 4.77 Yes 0.5-2.0 iQWC-012-GD t 1.10E+06 t 1.98E+05 1.84E+04 t 1.14 t Yes t Y 9.68E+05 1.16E+06 7.74E+05 1.10E+06 The Cs-137 activity in the standard measurement was 91% higher than Cs-137 activity in the QC measurement causing unacceptable agreement. Comparison was then made using K-40. There was acceptable agreement between the standard measurement and the replicate measurement. In addition, the Cs-137 data produces the same dose conclusion. No further action is necessary.

Yes N/A N/A SFC-032-GD Cs-137 4.31E+05 6.27E+04 2.54E+04 6.87 Yes 0.5-2.0 IQFC-032-GD I 5.49E+05 I 7.63E+04 2.49E+04 I 1.27 I Yes I Y 4.31E+05 5.17E+05 3.45E+05 5.49E+05 No 0.052 0.067 Cs-137 3.57E+04 1.31E+04 1.54E+04 2.73 Yes N/A 2.79E+04 1.26E+04 1.66E+04 N/A Yes N 3.57E+04 4.28E+04 2.86E+04 2.79E+04 No 0.004 0.003 SFC-048-GD K-40 9.21E+05 1.89E+05 1.22E+05 4.87 Yes 0.5-2.0 iQFC-048-GD t 9.96E+05 t 1.97E+05 1.23E+05 t 1.08 t Yes t Y 9.21E+05 1.11E+06 7.37E+05 9.96E+05 The resolution when using Cs-137 was unacceptable (<4). Comparison was then made using K-40. There was acceptable agreement between the standard measurement and the replicate measurement when using K-40. In addition, the standard concentration for Cs-137 is 22% of the replicate and the Cs-137 data produces the same dose conclusion. No further action is necessary.

Yes N/A N/A Acceptable Replicate Within Range of SU # Measurement OpSOF for Cs-137 ROC Activity Value Standard Error MDC Resolution >MDC Agreement Range Sample ID Activity Value Standard Error MDC Comparison Ratio >MDC Agreement +20% -20% Measurement -+20%

Sample ID Activity Standard Replicate (Y/N) Activity (Yes or no) 05100 Called replicate measurements in Release Record text, Used most current 84750 table (no <4 category) however, incorrectly used the agreement range of 0.1-2.5 and 0.4-2.5 for four measurements with resolutions <4 SWC-006-GD Cs-137 1.61E+05 3.62E+04 2.55E+04 4.45 Yes 0.5-2.0 QWC-006-GD 1.49E+05 3.60E+04 3.00E+04 0.93 Yes Y 1.61E+05 1.93E+05 1.29E+05 1.49E+05 Yes 0.020 0.018 SWC-024-GD Cs-137 1.70E+05 4.03E+04 3.61E+04 4.22 Yes 0.5-2.0 QWC-024-GD 1.63E+05 4.19E+04 4.37E+04 0.96 Yes Y 1.70E+05 2.04E+05 1.36E+05 1.63E+05 Yes 0.021 0.020 Cs-137 1.72E+04 1.92E+04 3.09E+04 0.90 No N/A -2.36E+04 1.30E+04 4.67E+04 N/A No N 1.72E+04 2.06E+04 1.38E+04 -2.36E+04 No 0.002 -0.003 SWC-074-GD K-40 1.31E+06 3.05E+05 3.02E+05 4.30 Yes 0.5-2.0 iQWC-074-GD t 9.95E+05 t 3.04E+05 3.18E+05 t 0.76 t Yes t Y The standard and replicate ISOCS measurements did not identify Cs-137 at activities greater than MDC. Comparison was then made using K-40. There was acceptable agreement between the standard measurement and the replicate measurement when using K-40. No further action is necessary.

1.31E+06 1.57E+06 1.05E+06 9.95E+05 No N/A N/A SWC-102-GD Cs-137 7.39E+05 1.08E+05 3.44E+04 6.84 Yes 0.5-2.0 IQWC-102-GD I 7.33E+05 I 1.08E+05 4.40E+04 I 0.99 I Yes I Y 7.39E+05 8.87E+05 5.91E+05 7.33E+05 Yes 0.090 0.089 Cs-137 4.57E+04 7.54E+03 5.32E+03 6.06 Yes 0.5-2.0 4.03E+05 6.96E+04 4.40E+04 8.82 Yes N 4.57E+04 5.48E+04 3.66E+04 4.03E+05 No 0.006 0.049 SWC-116-GD K-40 4.05E+04 3.07E+04 4.83E+04 1.32 No N/A iQWC-116-GD t 7.90E+05 t 2.38E+05 1.81E+05 t N/A t Yes t N 4.05E+04 4.86E+04 3.24E+04 7.90E+05 No N/A N/A The Cs-137 activity in the QC measurement was 89% higher than Cs-137 activity in the standard measurement causing unacceptable agreement. Comparison was then made using K-40 resulting in poor resolution (<4). Pre and post use operational checks of the ISOCS did not indicate any issues with the instrument or the quality of the data. In addition, other replicate measurements taken at several other locations were in agreement and the concentrations for Cs-137 produces the same conclusion pertaining to dose. No further action is necessary.

SWC-131-GD Cs-137 3.87E+05 6.45E+04 4.10E+04 6.00 Yes 0.5-2.0 QWC-131-GD 3.51E+05 5.93E+04 3.58E+04 0.91 Yes Y 3.87E+05 4.64E+05 3.10E+05 3.51E+05 Yes 0.047 0.043 III III SWC-132-GD Cs-137 3.58E+06 4.51E+05 7.28E+04 7.94 Yes 0.6-1.66 QWC-132-GD 3.60E+06 5.54E+05 6.94E+04 1.01 Yes Y 3.58E+06 4.30E+06 2.86E+06 3.60E+06 Yes 0.434 0.437 SWC-156-GD Cs-137 1.17E+07 1.43E+06 1.16E+05 8.18 Yes 0.6-1.66 QWC-156-GD 1.20E+07 1.46E+06 9.50E+04 1.03 Yes Y 1.17E+07 1.40E+07 9.36E+06 1.20E+07 Yes 1.420 1.456 SWC-167-GD Cs-137 1.18E+06 1.65E+05 6.14E+04 7.15 Yes 0.6-1.66 QWC-167-GD 1.31E+06 1.79E+05 5.96E+04 1.11 Yes Y 1.18E+06 1.42E+06 9.44E+05 1.31E+06 Yes 0.143 0.159 SWC-208-GD Cs-137 4.76E+06 5.95E+05 1.09E+05 8.00 Yes 0.6-1.66 QWC-208-GD 4.75E+06 5.95E+05 1.33E+05 1.00 Yes Y 4.76E+06 5.71E+06 3.81E+06 4.75E+06 Yes 0.578 0.576 SWC-218-GD Cs-137 4.80E+05 7.85E+04 4.19E+04 6.11 Yes 0.5-2.0 QWC-218-GD 4.24E+05 7.27E+04 4.58E+04 0.88 Yes Y 4.80E+05 5.76E+05 3.84E+05 4.24E+05 Yes 0.058 0.051 Cs-137 5.36E+04 3.15E+04 4.67E+04 1.70 Yes N/A 5.36E+04 3.16E+04 4.67E+04 N/A Yes N 5.36E+04 6.43E+04 4.29E+04 5.36E+04 Yes 0.007 0.007 SWC-230-GD K-40 1.11E+06 3.36E+05 3.37E+05 3.30 Yes N/A iQWC-230-GD t 1.11E+06 t 3.36E+05 3.73E+05 t N/A t Yes t N 1.11E+06 1.33E+06 8.88E+05 1.11E+06 Yes N/A N/A The initial comparison was made using Cs-137 with an inadequate resolution. An additional comparison was then made using K-40. There is not acceptable agreement between the standard and comparison measurements when using K-40, also due to poor resolution (<4). Pre and post use operational checks of the ISOCS did not indicate any issues with the instrument or the quality of the data. In addition, other replicate measurements taken at several other locations were in agreement. The Cs-137 concentrations for the standard and replicate measurements are with +20% and the Cs-137 data produces the same conclusion pertaining to dose.No further action is necessary.

Cs-137 1.28E+05 3.90E+04 4.62E+04 3.28 Yes N/A 1.53E+05 3.60E+04 2.83E+04 N/A Yes N 1.28E+05 1.54E+05 1.02E+05 1.53E+05 Yes 0.016 0.019 SWC-243-GD K-40 7.22E+05 3.35E+05 4.66E+05 2.16 Yes N/A iQWC-243-GD t 1.14E+06 t 3.19E+05 3.13E+05 t N/A t Yes t N 7.22E+05 8.66E+05 5.78E+05 1.14E+06 No N/A The initial comparison was made using Cs-137 with an inadaquate resolution. An additional comparison was then made using K-40. There is not acceptable agreement between the standard and comparison measurements when using K-40, also due to poor resolution. Pre and post use operational checks of the ISOCS did not indicate any issues with the instrument or the quality of the data. In addition, other replicate N/A measurements taken at several other locations were in agreement. The Cs-137 concentrations for the standard and replicate measurements are with +20% and the Cs-137 data produces the same conclusion pertaining to dose. No further action is necessary.

SWC-272-GD Cs-137 4.84E+06 6.15E+05 2.19E+05 7.87 Yes 0.6-1.66 QWC-272-GD 5.06E+06 6.44E+05 2.48E+05 1.05 Yes Y 4.84E+06 5.81E+06 3.87E+06 5.06E+06 Yes 0.587 0.614 SWC-292-GD Cs-137 1.69E+07 2.05E+06 1.62E+05 8.24 Yes 0.6-1.66 QWC-292-GD 1.69E+07 2.05E+06 1.76E+05 1.00 Yes Y 1.69E+07 2.03E+07 1.35E+07 1.69E+07 Yes 2.051 2.051

~

SWC-331-GD Cs-137 8.07E+05 1.19E+05 5.64E+04 6.78 Yes 0.6-1.66 QWC-331-GD 8.21E+05 1.21E+05 5.63E+04 1.02 Yes Y 8.07E+05 9.68E+05 6.46E+05 8.21E+05 Yes 0.098 0.100 SWC-333-GD Cs-137 4.57E+05 8.13E+04 6.55E+04 5.62 Yes 0.5-2.0 QWC-333-GD 5.01E+05 8.57E+04 6.39E+04 1.10 Yes Y 4.57E+05 5.48E+05 3.66E+05 5.01E+05 Yes 0.055 0.061 SWC-334-GD Cs-137 1.62E+06 2.26E+05 1.29E+05 7.17 Yes 0.6-1.66 QWC-334-GD 1.64E+06 2.29E+05 1.31E+05 1.01 Yes Y 1.62E+06 1.94E+06 1.30E+06 1.64E+06 Yes 0.197 0.199

~

SWC-341-GD Cs-137 1.99E+07 2.42E+06 1.76E+05 8.22 Yes 0.6-1.66 QWC-341-GD 2.09E+07 2.53E+06 1.58E+05 1.05 Yes Y 1.99E+07 2.39E+07 1.59E+07 2.09E+07 Yes 2.415 2.536 SWC-373-GD Cs-137 1.93E+06 2.54E+05 6.85E+04 7.60 Yes 0.6-1.66 QWC-373-GD 2.05E+06 2.68E+05 6.89E+04 1.06 Yes Y 1.93E+06 2.32E+06 1.54E+06 2.05E+06 Yes 0.234 0.249 SWC-395-GD Cs-137 3.89E+05 6.99E+04 5.15E+04 5.57 Yes 0.5-2.0 QWC-395-GD 4.41E+05 7.40E+04 4.30E+04 1.13 Yes Y 3.89E+05 4.67E+05 3.11E+05 4.41E+05 Yes 0.047 0.054

~

SWC-405-GD Cs-137 9.12E+05 1.33E+05 2.63E+04 6.86 Yes 0.5-2.0 QWC-405-GD 8.61E+05 1.29E+05 7.50E+04 0.94 Yes Y 9.12E+05 1.09E+06 7.30E+05 8.61E+05 Yes 0.111 0.104 SWC-409-GD Cs-137 1.76E+06 2.35E+05 8.16E+04 7.49 Yes 0.6-1.66 QWC-409-GD 1.61E+06 2.15E+05 5.96E+04 0.91 Yes Y 1.76E+06 2.11E+06 1.41E+06 1.61E+06 Yes 0.214 0.195 Page 10 of 17

ZionSolutions, LLC ZS-2021-0001 Supplemental Information Related to the Final Status Survey Final Reports ISOCS QC COMPARISON REVIEW (continued)

Acceptable Replicate Within Range of SU # Measurement OpSOF for Cs-137 ROC Activity Value Standard Error MDC Resolution >MDC Agreement Range Sample ID Activity Value Standard Error MDC Comparison Ratio >MDC Agreement +20% -20% Measurement +20%

Sample ID Activity Standard Replicate (Y/N) Activity (Yes or no) 06100 Called replicate measurements in Release Record text, Used most current 84750 table (no <4 category), all measurements in agreement K-40 7.88E+05 1.72E+05 1.19E+05 4.58 Yes 0.5-2.0 QWC-009-GD 8.44E+05 1.82E+05 1.32E+05 1.07 Yes Y 7.88E+05 9.46E+05 6.30E+05 8.44E+05 Yes N/A N/A RWC-009-GD The Cs-137 concentrations in both the standard and QC measurement was <MDC. Comparison was then made using K-40. There was acceptable agreement between the standard measurement and the replicate measurement. No further action is necessary.

K-40 1.81E+07 2.58E+06 8.67E+04 7.02 Yes 0.5-2.0 QWC-011-GD 1.80E+07 2.64E+06 1.57E+06 0.99 Yes Y 1.81E+07 2.17E+07 1.45E+07 1.80E+07 Yes N/A N/A RWC-011-GD The Cs-137 concentrations in both the standard and QC measurement was <MDC. Comparison was then made using K-40. There was acceptable agreement between the standard measurement and the replicate measurement. No further action is necessary.

Acceptable Replicate Within Range of SU # Measurement OpSOF for Cs-137 ROC Activity Value Standard Error MDC Resolution >MDC Agreement Range Sample ID Activity Value Standard Error MDC Comparison Ratio >MDC Agreement +20% -20% Measurement +20%

Sample ID Activity Standard Replicate (Y/N) Activity (Yes or no) 09200B Called replicate measurements in Release Record text, Used most current 84750 table (no <4 category)

K-40 8.88E+05 2.14E+05 1.00E+05 4.15 Yes 0.5-2.0 QCC-009-GD 8.90E+05 1.93E+05 1.18E+05 1.00 Yes Y 8.88E+05 1.07E+06 7.10E+05 8.90E+05 Yes N/A N/A RCC-009-GD Cs-137 concentration were >MDC in both the standard and QC measurement, Comparison was then made using K-40. There was acceptable agreement between the standard measurement and the replicate measurement. No further action is necessary.

Acceptable Replicate Within Range of SU # Measurement OpSOF for Cs-137 ROC Activity Value Standard Error MDC Resolution >MDC Agreement Range Sample ID Activity Value Standard Error MDC Comparison Ratio >MDC Agreement +20% -20% Measurement +20%

Sample ID Activity Standard Replicate (Y/N) Activity (Yes or no) 06107 Called replicate measurements in Release Record text, Used incorrect resolution Table from 84750 (<4 category listed), no measurement with that resolution, all in agreement JFC-005-GD K-40 7.03E+05 9.68E+04 4.28E+04 7.26 Yes 0.5-2.0 QFC-005-GD 7.09E+05 9.63E+04 3.43E+04 1.01 Yes Y 7.03E+05 8.44E+05 5.62E+05 7.09E+05 Yes N/A N/A Acceptable Replicate Within Range of SU # Measurement OpSOF for Cs-137 ROC Activity Value Standard Error MDC Resolution >MDC Agreement Range Sample ID Activity Value Standard Error MDC Comparison Ratio >MDC Agreement +20% -20% Measurement +20%

Sample ID Activity Standard Replicate (Y/N) Activity (Yes or no) 06108 Called replicate measurements in Release Record text, Used incorrect resolution Table from 84750 (<4 category listed), no measurement with that resolution, all in agreement JFC-002-GD K-40 7.08E+05 1.00E+05 5.73E+04 7.08 Yes 0.5-2.0 QFC-002-GD 6.66E+05 9.96E+04 7.23E+04 0.94 Yes Y 7.08E+05 8.50E+05 5.66E+05 6.66E+05 Yes N/A N/A Acceptable Replicate Within Range of SU # Measurement OpSOF for Cs-137 ROC Activity Value Standard Error MDC Resolution >MDC Agreement Range Sample ID Activity Value Standard Error MDC Comparison Ratio >MDC Agreement +20% -20% Measurement +20%

Sample ID Activity Standard Replicate (Y/N) Activity (Yes or no) 06201 Called replicate measurements in Release Record text, Used incorrect resolution Table from 84750 (<4 category listed), two measurements with resolution <4 but listed as acceptable, other measurements in agreement K-40 7.73E+05 2.37E+05 2.35E+05 3.26 Yes N/A QFC-002-GD 9.68E+05 2.52E+05 2.02E+05 N/A Yes N 7.73E+05 9.28E+05 6.18E+05 9.68E+05 No N/A N/A SFC-002-GD The Cs-137 concentrations listed on the Replicate Measurement Assessment form in the Release Record is actually K-40 concentrations as Cs-137 is actually <MDC. The original comparison of concentrations was listed as acceptable even though the resolution was unacceptable (<4). Pre and post use operational checks of the ISOCS did not indicate any issues with the instrument or the quality of the data. In addition, other replicate measurements taken at several other locations were in agreement. The concentrations for the standard and replicate measurements are within 21% and the data produces the same conclusion. No further action is necessary.

SFC-025-GD Cs-137 1.65E+05 3.48E+04 2.62E+04 4.74 Yes 0.5-2.0 QFC-025-GD 1.64E+05 3.37E+04 2.16E+04 0.99 Yes Y 1.65E+05 1.98E+05 1.32E+05 1.64E+05 Yes 0.020 0.020 Cs-137 3.13E+04 1.52E+04 1.91E+04 2.06 Yes N/A 3.56E+04 1.55E+04 1.83E+04 N/A Yes N 3.13E+04 3.76E+04 2.50E+04 3.56E+04 Yes 0.004 0.004 QWC-046-GD K-40 9.76E+05 2.59E+05 2.26E+05 3.77 Yes N/A 7.83E+05 2.31E+05 2.11E+05 N/A Yes N 9.76E+05 1.17E+06 7.81E+05 7.83E+05 Yes N/A N/A SWC-046-GD The original comparison of Cs-137 concentrations was listed as acceptable even though the resolution was unacceptable (<4). Comparisons were also made using the K-40 concentrations. Resolution was poor with both comparisons (<4). Pre and post use operational checks of the ISOCS did not indicate any issues with the instrument or the quality of the data. In addition, other replicate measurements taken at several other locations were in agreement. The concentrations for Cs-137 and K-40 in the standard and replicate measurements are with +20% and the Cs-137 data produces the same dose conclusion. No further action is necessary.

Acceptable Replicate Within Range of SU # Measurement OpSOF for Cs-137 ROC Activity Value Standard Error MDC Resolution >MDC Agreement Range Sample ID Activity Value Standard Error MDC Comparison Ratio >MDC Agreement +20% -20% Measurement +20%

Sample ID Activity Standard Replicate (Y/N) Activity (Yes or no) 06202 Called replicate measurements in Release Record text, Used incorrect resolution Table from 84750 (<4 category listed), the resolution for measurement SWC-038-GD rounded up to 4, all measurements in agreement SFC-005-GD K-40 1.20E+06 2.78E+05 1.91E+05 4.32 Yes 0.5-2.0 QFC-005-GD 1.00E+06 2.57E+05 2.03E+05 0.83 Yes Y 1.20E+06 1.44E+06 9.60E+05 1.00E+06 Yes N/A N/A SFC-012-GD K-40 1.04E+06 2.40E+05 3.21E+04 4.33 Yes 0.5-2.0 QFC-012-GD 9.24E+05 2.65E+05 2.64E+05 0.89 Yes Y 1.04E+06 1.25E+06 8.32E+05 9.24E+05 Yes N/A N/A SWC-038-GD K-40 9.89E+05 2.50E+05 1.77E+05 3.96 Yes 0.5-2.0 QWC-038-GD 1.13E+06 2.60E+05 1.36E+05 1.14 Yes Y 9.89E+05 1.19E+06 7.91E+05 1.13E+06 Yes N/A N/A Acceptable Replicate Within Range of SU # Measurement OpSOF for Cs-137 ROC Activity Value Standard Error MDC Resolution >MDC Agreement Range Sample ID Activity Value Standard Error MDC Comparison Ratio >MDC Agreement +20% -20% Measurement +20%

Sample ID Activity Standard Replicate (Y/N) Activity (Yes or no) 06213 Called replicate measurements in Release Record text, Used most current 84750 table (no <4 category), all measurements in agreement SFC-002-GD Cs-137 7.06E+06 8.68E+05 5.92E+04 8.13 Yes 0.6-1.66 QFC-002-GD 7.04E+06 8.66E+05 6.17E+04 1.00 Yes Y 7.06E+06 8.47E+06 5.65E+06 7.04E+06 Yes 0.857 0.854 SWC-020-GD Cs-137 1.89E+05 4.15E+04 3.25E+04 4.55 Yes 0.5-2.0 QWC-020-GD 1.22E+05 3.05E+04 2.27E+04 0.65 Yes Y 1.89E+05 2.27E+05 1.51E+05 1.22E+05 Yes 0.023 0.015 Acceptable Replicate Within Range of SU # Measurement OpSOF for Cs-137 ROC Activity Value Standard Error MDC Resolution >MDC Agreement Range Sample ID Activity Value Standard Error MDC Comparison Ratio >MDC Agreement +20% -20% Measurement +20%

Sample ID Activity Standard Replicate (Y/N) Activity (Yes or no) 06214 Called replicate measurements in Release Record text, Used most current 84750 table (no <4 category), all measurements in agreement Cs-137 2.86E+04 1.67E+04 2.22E+04 1.71 Yes N/A 2.85E+04 1.65E+04 2.16E+04 N/A Yes N 2.86E+04 3.43E+04 2.29E+04 2.85E+04 Yes 0.003 0.003 SWC-007-GD QWC-007-GD K-40 7.91E+05 2.75E+05 3.05E+05 2.88 Yes N/A 8.95E+05 2.65E+05 2.32E+05 N/A Yes N 7.91E+05 9.49E+05 6.33E+05 8.95E+05 Yes N/A N/A The initial comparison was made using Cs-137 with an inadequate resolution. An additional comparison was then made using K-40. There is not acceptable agreement between the standard and comparison measurements when using K-40, also due to poor resolution. Pre and post use operational checks of the ISOCS did not indicate any issues with the instrument or the quality of the data. In addition, other replicate measurements taken at several other locations were in agreement. The Cs-137 concentrations for the standard and replicate measurements are with +20% and the Cs-137 data produces the same conclusion pertaining to dose. No further action is necessary.

SWC-016-GD Cs-137 1.79E+05 3.84E+04 2.44E+04 4.66 Yes 0.5-2.0 QWC-016-GD 2.13E+05 4.28E+04 2.53E+04 1.19 Yes Y 1.79E+05 2.15E+05 1.43E+05 2.13E+05 Yes 0.022 0.026 Page 11 of 17

ZionSolutions, LLC ZS-2021-0001 Supplemental Information Related to the Final Status Survey Final Reports ISOCS QC COMPARISON REVIEW (continued)

Acceptable Replicate Within Range of SU # Measurement OpSOF for Cs-137 I ROC Activity Value Standard Error MDC Resolution >MDC Agreement Range Sample ID Activity Value Standard Error MDC Comparison Ratio >MDC Agreement +20% -20% Measurement -+20%

Sample ID Activity Standard Replicate (Y/N) Activity (Yes or no) 06215 Called replicate measurements in Release Record text, Used most current 84750 table (no <4 category), one QC measurement taken, Cs-137 >MDC, low resolution for K-40 SWC-018-GD K-40 1.04E+06 l 2.83E+05 2.31E+05 3.67 Yes N/A lQWC-018-GD l 1.32E+06 l 3.23E+05 2.53E+05 N/A Yes l N l 1.04E+06 l 1.25E+06 8.32E+05 1.32E+06 No N/A l N/A tThe Cs-137 concentrations listed on the Replicate Measurement Assessment form in the Release Record is actually K-40 concentrations as Cs-137 is actually <MDC. The original comparison of concentrations was listed as out of agreement as the resolution was unacceptable (<4). Pre and post use operational checks of the ISOCS did not indicate any issues with the instrument or the quality of the data. In addition, other replicate measurements taken at several other locations were in agreement. The concentrations for the standard and replicate measurements are within 27% and the data produces the same conclusion. No further action is necessary.

Acceptable Replicate Within Range of SU # Measurement OpSOF for Cs-137 ROC Activity Value Standard Error MDC Resolution >MDC Agreement Range Sample ID Activity Value Standard Error MDC Comparison Ratio >MDC Agreement +20% -20% Measurement -+20%

Sample ID Activity Standard Replicate (Y/N) Activity (Yes or no) 06216 Called replicate measurements in Release Record text, Used most current 84750 table (no <4 category), one measurement within agreement SFC-003-GD ICs-137 2.90E+05 I 5.55E+04 3.99E+04 5.23 Yes 0.5-2.0 IQFC-003-GD I 2.86E+05 I 5.35E+04 3.37E+04 0.99 Yes I Y I 2.90E+05 3.48E+05 2.32E+05 2.86E+05 Yes 0.035 I 0.035 Acceptable Replicate Within Range of SU # Measurement OpSOF for Cs-137 ROC Activity Value Standard Error MDC Resolution >MDC Agreement Range Sample ID Activity Value Standard Error MDC Comparison Ratio >MDC Agreement +20% -20% Measurement -+20%

Sample ID Activity Standard Replicate (Y/N) Activity (Yes or no) 08100 Called replicate measurements in Release Record text, Used most current 84750 table (no <4 category), one measurement within agreement Cs-137 0.00E+00 1.08E+02 2.52E+02 0.00 No N/A 4.89E+01 1.76E+02 3.60E+01 N/A Yes N 0.00E+00 0.00E+00 0.00E+00 4.89E+01 No 0.000 0.000 L

RWC-014-GM f

K-40 4.12E+04 t 6.36E+03 3.21E+04 6.48 Yes 0.5 - 2.0 iQWC-014-GM r 3.71E+04 t 5.63E+03 6.80E+03 0.90 Yes t Y t The standard and replicate ISOCS measurements did not identify Cs-137 at activities greater than MDC. Comparison was then made using K-40. There was acceptable agreement between the standard measurement and the replicate measurement when using K-40. No further action is necessary.

4.12E+04 4.94E+04 3.30E+04 3.71E+04 Yes N/A t N/A Acceptable Replicate Within Range of SU # Measurement OpSOF for Cs-137 ROC Activity Value Standard Error MDC Resolution >MDC Agreement Range Sample ID Activity Value Standard Error MDC Comparison Ratio >MDC Agreement +20% -20% Measurement -+20%

Sample ID Activity Standard Replicate (Y/N) Activity (Yes or no) 09100 Called replicate measurements in Release Record text, Used most current 84750 table (no <4 category), two measurements within agreement using K-40 SFC-009-GD Cs-137 3.15E+03 1.12E+04 2.40E+04 0.28 No N/A QFC-009-GD -1.09E+04 9.59E+03 2.14E+04 N/A No N 3.15E+03 3.78E+03 2.52E+03 -1.09E+04 No 0.000 -0.001 tK-40 1.22E+06 t 2.36E+05 1.92E+05 5.17 Yes 0.5-2.0 t t 1.01E+06 t 2.48E+05 1.41E+05 0.83 Yes t Y t The standard and replicate ISOCS measurements did not identify Cs-137 at activities greater than MDC. Comparison was then made using K-40. There was acceptable agreement between the standard measurement and the replicate measurement when using K-40. No further action is necessary.

1.22E+06 t 1.46E+06 9.76E+05 1.01E+06 Yes N/A t N/A SFC-014-GD Cs-137 2.57E+04 1.27E+04 2.76E+04 2.02 No N/A QFC-014-GD 3.56E+03 1.15E+04 2.53E+04 N/A No N 2.57E+04 3.08E+04 2.06E+04 3.56E+03 No 0.003 0.000 K-40

~

7.60E+05 t 2.13E+05 1.77E+05 3.57 Yes N/A t t 8.85E+05 t 2.20E+05 1.35E+05 N/A Yes t N t 7.60E+05 t 9.12E+05 6.08E+05 8.85E+05 Yes N/A t N/A SWC-027-GD tThe standard and replicate ISOCS measurements did not identify Cs-137 at activities greater than MDC. Comparison was then made using K-40. There is not acceptable agreement between the standard and comparison measurements when using K-40, also due to poor resolution. Pre and post use operational checks of the ISOCS did not indicate any issues with the instrument or the quality of the data. In addition, other replicate measurements taken at several other locations were in agreement. No further action is necessary.

Cs-137 2.57E+04 1.27E+04 2.76E+04 2.02 No N/A QWC-027-GD -3.54E+02 1.26E+04 2.73E+04 N/A No N 2.57E+04 3.08E+04 2.06E+04 -3.54E+02 No 0.003 0.000 tK-40 1.06E+06 t 2.34E+05 2.93E+04 4.53 Yes 0.5-2.0 t t 1.11E+06 t 2.48E+05 1.30E+05 1.05 Yes t Y t The standard and replicate ISOCS measurements did not identify Cs-137 at activities greater than MDC. Comparison was then made using K-40. There was acceptable agreement between the standard measurement and the replicate measurement when using K-40. No further action is necessary.

1.06E+06 t 1.27E+06 8.48E+05 1.11E+06 Yes N/A t N/A SWC-053-GD Cs-137 6.59E+03 1.47E+04 3.16E+04 0.45 No N/A QWC-053-GD 3.34E+04 1.29E+04 1.28E+04 N/A Yes N 6.59E+03 7.91E+03 5.27E+03 3.34E+04 No N/A N/A K-40 7.14E+05 t 2.03E+05 1.59E+05 3.52 Yes N/A t t 8.35E+05 t 2.04E+05 2.93E+04 N/A Yes t N t 7.14E+05 t 8.57E+05 5.71E+05 8.35E+05 Yes N/A t N/A tThe standard and replicate ISOCS measurements did not identify Cs-137 at activities greater than MDC. Comparison was then made using K-40. There is not acceptable agreement between the standard and comparison measurements when using K-40, also due to poor resolution. Pre and post use operational checks of the ISOCS did not indicate any issues with the instrument or the quality of the data. In addition, other replicate measurements taken at several other locations were in agreement. No further action is necessary.

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ZionSolutions, LLC ZS-2021-0001 Supplemental Information Related to the Final Status Survey Final Reports Additional NRC Question #3 Review the Attachment 3 spreadsheet from the RAI response and discuss the assessment of non-ROC full suite radionuclides that presented as >MDC (such as Tc-99). Also, weave the statement in the Eberline report about false positive for Tc-99 into the Release Records).

RESPONSE: The spreadsheet submitted as an Attachment to the ZSRP RAI responses to Request for Additional Information Related to Final Status Survey Reports Phase 2A, 2B, and 3 dated May 2020 was reviewed. The results provided in Tab - SAMPLE ANALYSIS (ALL ISOTOPES) from Attachment 1 present the analytical results for the full suite analysis performed by Eberline Laboratories on 15 concrete core samples, 2 subsurface soil samples, and one sediment sample. These samples were sent for full suite isotopic analysis to address NRC concerns in response to RAIs 1a, 3b, 3d, 4a, 4b, 4f, and 4h.

Table 5-2 of LTP Chapter 5 presents the Radionuclides of Concern (ROC) for the Zion decommissioning which include Co-60, Ni-63, Sr-90, Cs-134, Cs-137, and H-3, Eu-152, and Eu-155 for Containment. Cs-137 was positively detected in 5 of the 18 samples, and Co-60 was positively detected in one. In addition, the analytical results from Eberline showed positive concentrations of Tc-99 in 17 of the 18 samples that were analyzed. In addition, Np-237 and Cm-243/244 were positively detected in concrete core sample B2-06104-CJFC-003-CV, Pu-238 was positively detected in concrete core sample B1-06201A-FSWC-041-CV, Eu-155 was positively detected in concrete core sample B2-08101A-BJFC-007-CV, Eu-154 was positively detected in sediment sample L2-10214C-RJGS-001-SM-A, Eu-155 was positively detected in subsurface soil sample L1-12109L-CJGS-001-SB-A, and CM-243/244 was positively detected in concrete sample B1-06201A-FSWC-050-CV. These radionuclides (Tc-99, Eu-154, Np-237, Pu-238, Cm-243/244), as well as Eu-155 outside of Containment, were included in LTP Chapter 5, Table 5-1 as potential plant-derived radionuclides but were not included as ROC in LTP Chapter 5, Table 5-2, as they were classified as Insignificant Contributors (IC) to dose. The elimination of IC from the initial suite is consistent with the guidance in NUREG-1757.

To account for the potential dose from IC radionuclides, the Base Case DCGLs for structures other than Containment were reduced by 5%, and the Base Case DCGLs for Containment and soils were reduced by 10%. To ensure that the IC dose adjustments are not exceeded, LTP Chapter 5, section 5.1 requires that the actual IC dose is calculated in samples analyzed for the full suite of radionuclides. This calculation was performed and documented in the Tab-SAMPLE ANALYSIS ASSESSMENT from Attachment 1, and it includes all the positively detected IC radionuclide concentrations specified with the exception of Tc-99. The calculations presented in the Attachment 1 spreadsheet show that the residual detectable concentrations had no consequence on mixture, IC dose adjustments, or ratios.

As previously described, positive concentrations of Tc-99 were identified in 17 of the 18 samples sent to Eberline to support the RAI responses. Due to the fact that Tc-99 was not positively Page 13 of 17

ZionSolutions, LLC ZS-2021-0001 Supplemental Information Related to the Final Status Survey Final Reports detected in any of the previous samples sent to Eberline for full suite isotopic analysis and the presence of Tc-99 in the locations where the samples were taken was very unlikely, the project contacted Eberline in May of 2020 for possible explanations. Copies of the correspondences were included in Attachment 3 to the ZSRP RAI response submitted in May 2020.

The e-mail correspondences from the Eberline Laboratory manager state that false positives for Tc-99 are caused by noise equivalent for the analytical technique. Technetium-99 is counted by beta liquid scintillation and is prone to background noise variations directly related to the counting method. Using an absolute value that is less than the MDC is not appropriate for a beta liquid scintillation method when the value at these levels is +/- 200% of the value. This was typical for all of the Tc-99 data that we reported in Tab - SAMPLE ANALYSIS (ALL ISOTOPES) from Attachment 1. The Eberline Lab Manager indicated in the correspondence that the Tc-99 reported in the analytical results for the 17 samples were indeed false positive and that Tc-99 was not positively identified by the analysis. Consequently, Tc-99 was not identified as a positively detected radionuclide for the assessment of IC dose presented in Tab-SAMPLE ANALYSIS ASSESSMENT from Attachment 1. However, it should be noted that the actual reported concentrations of Tc-99 were included in the calculation of the IC dose for each sample.

As part of this question, the NRC indicated that they preferred that the discussion pertaining to false positives for Tc-99 be included in relevant release records. The following text will be added to the release records for survey units 06100, 06201, 06202, 06213/06214, and 08100:

For the samples submitted for full isotopic analysis, Tc-99 was initially identified as positively detected at concentrations greater than MDC. Upon consultation with the laboratory, false positives for Tc-99 can be caused by noise equivalent for the analytical technique and an absolute value that is less than the MDC is not appropriate for a beta liquid scintillation method when the MDC is +/- 200% of the value. With concurrence of the laboratory, the positively identified Tc-99 initially identified during the full isotopic analysis of samples from this survey unit was changed to a false positive.

Supplemental or Revised Documentation: Revised release records for survey units 06100, 06201, 06202, 06213/06214, and 08100 Additional NRC Question #4 Ensure consistency between penetration dose presented in the revised penetration release record and the dose values presented in the Attachment 3 spreadsheet.

RESPONSE: The version of the Penetrations release record submitted with the ZSRP RAI response to Request for Additional Information Related to Final Status Survey Reports Phase 2A, 2B, and 3 from May 2020 was reviewed. The review showed that several tables were not updated with the exact values provided in Tab - SAMPLE PENETRATIONS from . A new dose calculation spreadsheet (Penetration Dose Calculation) was created Page 14 of 17

ZionSolutions, LLC ZS-2021-0001 Supplemental Information Related to the Final Status Survey Final Reports and is provided in the enclosure to the response. Release Record 01112/02112/05120 has been revised to update all data tables, as well as text where appropriate, so that they reflect the correct values provided in the Penetration Dose Calculation spreadsheet. Additionally, the Phase 2, Part 1 Final Report was revised to reflect the changes to the Penetrations release record. ZS-2020-0011 Attachment, Supporting Information for the Phased Release of Land from the 10 CFR Part 50 License was revised to reflect the changes to the Phase 2, Part 1 Final Report.

Supplemental or Revised Documentation: Revised release record for survey unit 01112/02112/05120, Penetration Dose Calculation spreadsheet, the Phase 2, Part 1 Final Report, and the ZS-2020-0011 Attachment, Revision 2, Supporting Information for the Phased Release of Land from the 10 CFR Part 50 License Additional NRC Question #5 Ensure assumptions used in the dose calculation for the ORISE identified pipe are correct (cited use of efficiency and viable detector, pipe size). This is a follow up question on the response to RAI 5c, submitted May 2020.

RESPONSE: Because of information that was provided by the NRC during a recent conference call (subsequent to the original response to RAI 5c), ZionSolutions has determined that a review of the assumptions used in the dose calculation for the ORISE identified pipe is not necessary.

The calculations were based on the assumption that the pipe was 6 in diameter and part of the Turbine Building embedded pipe system, when, in fact, the pipes much smaller diameter verifies the pipe could not be part of a process system. The pipe is likely a piece of conduit.

ZionSolutions performed a review of the cited ORAU report dated August 2016. The report mentions that at one of the judgmental sample locations (ISOCS-J-03), Cs-137 was measured in the spectrum. Further investigation with the NaI detector revealed that the source of the direct gamma radiation was originating from embedded piping in the floor. Section 7.2 of the ORAU report details that embedded piping located to the right of the earthen ramp (if facing east) had readings above background at 8,500 cpm. ZionSolutions assumes the embedded piping mentioned in Section 7.2 is the same embedded piping associated with judgmental measurement ISOCS-J-03.

Section 7.3 of the ORAU report details the ISOCS measurements obtained during their confirmatory surveys. The report states, Judgmental measurement location ISOCS-J-03 was located on the floor of the turbine building and Cs-137 was identified in the measurement spectrum. Further investigation with the NaI detector revealed the source of the direct gamma radiation was originating from two embedded pipes in the floor. During a subsequent conference call, an NRC reviewer stated that the ORAU technician that performed the gamma radiation survey stated the pipe was 1 to 2 in diameter.

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ZionSolutions, LLC ZS-2021-0001 Supplemental Information Related to the Final Status Survey Final Reports The only embedded piping that remained in the Turbine Building at the time of FSS were equipment or floor drain piping that were 4 or 6 in diameter (see Release Record 06105B).

ZionSolutions believes that the smaller diameter pipe identified by ORAU was in fact electrical conduit that was cut flush to the floor, and typically with the cabling still inside the pipe.

Because conduit is not a fluid or air-bearing system, it was not subject to FSS. ZionSolutions believes that the elevated readings were due to dirt and debris that concentrated around the conduit openings.

Because the conduit is not a fluid or air-bearing system, the grouting criteria is not applicable.

Because the ISOCS measurement taken directly over the elevated readings identified ROC at less than 1% of the OpDCGLB for the Turbine floor and walls, ZionSolutions contends there are no potential dose consequences attributable to this piping.

Additional NRC Question #6 Provide additional info on Phase 2 Part 2 RAI #7 response (check outfall of ISFSI storm drain, all other storm drains were removed).

RESPONSE: The buried pipe presented in TSD-14-016, Description of Embedded Piping, Penetrations and Buried Pipe to Remain in the Zion End State, Attachment N, lists all impacted buried pipe that remains at Zion. In addition to the pipe specified in that list, there were two additional storm drain systems that were initially designated as non-impacted and not included in Attachment N. The first is the storm drain that supports the ISFSI site. The drainage pipe was installed as part of the ISFSI construction, and it is located along the south boundary of the site.

The second was the North Yard storm drain that services the Switchyard that was reclassified as impacted Class 2 when plant-derived residual radioactivity was discovered during a surveillance.

Surveillances were also performed at the ISFSI drainage outfall, and to date no residual radioactivity has been positively identified at that location. All other buried pipe, except for the ISFSI drainage pipe and the pipe listed in Attachment N to TSD-14-016, have been excavated, removed, and disposed of as waste.

Additional NRC Question #7 Revise release record for 10221B to remove the word subsequent.

RESPONSE: The release record has been revised to clarify the sequencing of surveys. Please see the response to NRC Question #3 for more information.

Additional NRC Question #8 Provide RA results for remediation and excavation of Power Block soils which occurred prior to ORISE confirmatory surveys.

RESPONSE: As requested, copies of the documentation of the RA surveys performed to support the remediation of the subsurface soils in the Power Block are provided on the enclosure to this response.

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ZionSolutions, LLC ZS-2021-0001 Supplemental Information Related to the Final Status Survey Final Reports Supplemental or Revised Documentation: Power Block RA Report Attachments and Power Block RA Readiness Review Page 17 of 17