ML19077A052

Final Status Survey (FSS) Final Report - Phase 2, Part 1 - Turbine Building Basement Survey, Unit 06100

ML19077A052
Person / Time
Site:	Zion  File:ZionSolutions icon.png
Issue date:	02/28/2019
From:	Giza P ZionSolutions
To:	Office of Nuclear Material Safety and Safeguards
References
ZS-2019-0017
Download: ML19077A052 (482)

Text

ZION STATION RESTORATION PROJECT FINAL STATUS SURVEY RELEASE RECORD TURBINE BUILDING BASEMENT SURVEY UNIT 06100

FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 PREPARED BY / DATE: P. Giza 2/28/2019 Radiological Engineer REVIEWED BY / DATE: R. Massengill 2/28/2019 Radiological Engineer APPROVED BY / DATE: D. Wojtkowiak 2/28/2019 C/LT Manager

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 TABLE OF CONTENTS

1. EXECUTIVE

SUMMARY

................................................................................................... 6

2. CLASSIFICATION BASIS .................................................................................................. 9

3. SURVEY UNIT DESCRIPTION ....................................................................................... 13

4. DATA QUALITY OBJECTIVES (DQO) ......................................................................... 18

5. SURVEY DESIGN .............................................................................................................. 21

6. SURVEY IMPLEMENTATION........................................................................................ 34

7. SURVEY RESULTS............................................................................................................ 35

8. QUALITY CONTROL ....................................................................................................... 45

9. INVESTIGATIONS AND RESULTS ............................................................................... 45

10. REMEDIATION AND RESULTS ..................................................................................... 46

11. CHANGES FROM THE SURVEY PLAN ....................................................................... 46

12. DATA QUALITY ASSESSMENT (DQA) ........................................................................ 46

13. ANOMALIES....................................................................................................................... 46

14. COMPLIANCE EQUATION............................................................................................. 47

15. CONCLUSION .................................................................................................................... 49

16. REFERENCES .................................................................................................................... 50

17. ATTACHMENTS ................................................................................................................ 51 ATTACHMENT 1 - MAPS ................................................................................................... 52 ATTACHMENT 2 - GRAPHICAL PRESENTATIONS ...................................................... 57 ATTACHMENT 3 - SIGN TEST .......................................................................................... 63 ATTACHMENT 4 - QC MEASUREMENT ASSESSMENT............................................... 66 ATTACHMENT 5 - ISOCS GEOMETRY ........................................................................... 72 ATTACHMENT 6 - ISOCS REPORTS ................................................................................ 83

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 LIST OF TABLES Table 1 - Turbine Building 560 Foot and 570 Foot Elevation Concrete Core Sample Analysis Summary ................................................................................................................. 11 Table 2 - Dose Significant Radionuclides and Mixture.......................................................................... 19 Table 3 - Base Case DCGLs (BcDCGLB) for the Turbine Building Basement Survey Unit - LTP Chapter 5, Table 5-3 ........................................................................................... 20 Table 4 - Operational DCGLs (OpDCGLB) for the Turbine Building Basement Survey Unit - LTP Chapter 5, Table 5-4 ........................................................................................... 21 Table 5 - Surrogate Ratios ...................................................................................................................... 22 Table 6 - Surrogate Operational DCGLs for Turbine Building .............................................................. 22 Table 7 - Action Levels for Turbine Building ........................................................................................ 23 Table 8 - Adjusted Minimum Number of ISOCS Measurements .......................................................... 24 Table 9 - Random ISOCS Measurement Locations for Turbine Building Structures ........................... 25 Table 10 - Judgmental ISOCS Measurement Locations for Turbine Building Structures .................... 26 Table 11 - Random ISOCS Measurement Locations for Unit 1 and Unit 2 Steam Tunnels ................. 27 Table 12 - Judgmental ISOCS Measurement Locations for Unit 1 and Unit 2 Steam Tunnels ............ 28 Table 13 - Judgmental ISOCS Measurement Locations for Circulating Water Discharge Tunnels ..... 29 Table 14 - Judgmental ISOCS Measurement Locations for Circulating Water Discharge Pipe ........... 30 Table 15 - Investigation Levels .............................................................................................................. 32 Table 16 - Synopsis of Survey Design ................................................................................................... 33 Table 17 - Summary of ISOCS Results for Random Measurements ..................................................... 35 Table 18 - Basic Statistical Properties of Random ISOCS Measurements ............................................ 37 Table 19 - Summary of ISOCS Replicate Measurement for QC............................................................ 37 Table 20 - Summary of ISOCS Results for Judgmental Measurements Taken in the Turbine Building Basement and Steam Tunnels .................................................................. 38 Table 21 - Summary of Gamma Spectroscopy Results for Judgmental ISOCS Measurements Taken in Circulating Water Discharge Pipes........................................................................ 39 Table 22 - Basic Statistical Properties of Judgmental ISOCS Measurements in Circulating Water Discharge Pipe .................................................................................... 39 Table 23 - Summary of Results for Judgmental Measurements Taken in the Circulating Water Discharge Tunnels ........................................................................ 40 Table 24 - Basic Statistical Properties of Judgmental ISOCS Measurements in Circulating Water Discharge Tunnel ................................................................................ 41 Table 25 - Summary of Replicate Measurement Taken in Circulating Water Discharge Tunnel for QC ........................................................................ 41 Table 26 - Summary of Final Status Surveys Performed in Ancillary Areas and in Embedded Piping within the Turbine Building Basement ................................................... 43 Table 27 - Surface Survey Units Contributing to the Turbine Building Basement ................................ 44

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 LIST OF FIGURES Figure 1 - Turbine Building Characterization Concrete Core Locations ............................................... 10 Figure 2 - Turbine Building Basement 560 ft. Elevation ....................................................................... 15 Figure 3 - Turbine Building Basement North ......................................................................................... 16 Figure 4 - Turbine Building Demolition................................................................................................. 17 Figure 5 - 510 Valve Pit Circulating Service Water Discharge Pipe ..................................................... 30

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100

1. EXECUTIVE

SUMMARY

This Final Status Survey (FSS) Release Record for Survey Unit B3-06100, Turbine Building Basement, Survey Unit B3-09200B, Circulating Water Discharge Tunnels and Survey Unit S3-06105AS, Unit 1 and Unit 2 Circulating Water Discharge Pipe has been generated for the Zion Station Restoration Project (ZSRP). The release record was developed in accordance with ZionSolutions procedure ZS-LT-300-001-005, Final Status Survey Data Reporting (Reference 1) and satisfies the requirements of Section 5.11 of the Zion Station Restoration Project License Termination Plan (LTP) (Reference 2). The FSS package for basement Survey Unit B3-06100, Turbine Building, Survey Unit B3-09200B, Circulating Water Discharge Tunnels and Survey Unit S3-06105AS, Unit 1 and Unit 2 Circulating Water Discharge Pipe also includes FSS design and FSS results for the following. The stand-alone Release Records for each are attached to this document as Appendixes;

• S3-06105B Turbine Building 560 foot Embedded Floor Drain Pipe

• S3-06209A Unit 1 Steam Tunnel Embedded Floor Drain Pipe

• S3-06210A Unit 2 Steam Tunnel Embedded Floor Drain Pipe

• B1-06113/14A Unit 1 East and West Valve Houses

• B3-06115/16A Unit 2 East and West Valve Houses

• B1-06201A Unit 1 Diesel Fuel Oil Storage Tank Room

• B1-06202A Unit 2 Diesel Fuel Oil Storage Tank Room

• B3-06107A Unit 1 Tendon Buttress Pits

• B3-06108A Unit 2 Tendon Buttress Pits

• S3-06211A Unit 1 Tendon Tunnel 547 foot Embedded Floor Drain Pipe

• S3-06212A Unit 2 Tendon Tunnel 547 foot Embedded Floor Drain Pipe Final Status Survey (FSS) sample plans for each of these survey units were developed in accordance with ZionSolutions procedure ZS-LT-300-001-001, Final Status Survey Package Development (Reference 3), the ZSRP LTP, and guidance from NUREG-1575, Revision 1, Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM) (Reference 4).

FSS was conducted to demonstrate that the concentrations of residual radioactivity are equal to or below site-specific Derived Concentration Guideline Levels (DCGL) corresponding to the dose criterion in 10 CFR 20.1402.

In accordance with ZSRP LTP Chapter 5, section 5.5.2.1 and Table 5-19, the Turbine Building basement and the Circulating Water Discharge Tunnels are classified as MARSSIM Class 3.

The Circulating Water Intake and Discharge pipe, the Steam Tunnels, the Tendon Tunnels, the Buttress Pits and the associated embedded piping are integral to the Turbine Building basement and are also classified as MARSSIM Class 3. The Unit 1 and Unit 2 570 foot Diesel Generator rooms were also initially classified as MARSSIM Class 3. However, during the course of decommissioning, unpackaged radioactive material was transported through these areas from

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 the Auxiliary Building. Consequently, the Unit 1 and Unit 2 570 foot Diesel Generator rooms were reclassified during decommissioning to MARSSIM Class 1.

Unit 1 East and West Valve Houses (Survey Units B1-06113/14A) were initially classified as Class 3 but during FSS activity, activity was detected at concentrations greater than 50% of the release criteria. Consequently, these survey units were reclassified as Class 1.

Survey plans were designed based upon use of the Sign Test as the nonparametric statistical test for compliance. Both the Type I () and Type II () decision error rates were set at 0.05.

The Canberra In Situ Object Counting System (ISOCS) was selected as the primary instrument used to perform FSS of the Turbine Building basement, Circulating Water Tunnels and Circulating Water Discharge Pipe survey units. In accordance with LTP Chapter 5, Table 5-23, the surface area of the complete Turbine Building Basement survey unit (including all ancillary areas) was determined to be 27,135 m2.

In accordance with LTP Chapter 5, Table 5-19, the minimum number of measurements necessary in the Turbine Building basement (which includes the area of the Steam Tunnels, the Diesel Generator Rooms, the Tendon Tunnels and the Valve Houses) and inside of the Circulating Water Tunnels was 14 each. In addition, 4 judgmental measurements were acquired in the Circulating Water Discharge Pipe. During FSS, a total of 28 random ISOCS measurements and 173 judgmental ISOCS measurements were taken on structural surfaces in the Turbine Building basement. Additionally, three-hundred twenty-seven (327) random measurements were taken during FSS within embedded pipe systems that remain in the Turbine Building basement.

In accordance with ZionSolutions TSD 14-016, Description of Embedded Piping, Penetrations, and Buried Pipe to Remain in Zion End State (Reference 5), there were 11 penetrations (T91, T92, T93, T94, T96, T97, T98, T99, T100, T101 and T104) that accessed the exterior C wall of the Turbine Building basement (east wall) between 585 foot and the 586 foot elevation. The pipes were all removed in April of 2017 during decommissioning and the penetration openings in the Turbine Building east and west walls were grouted as required by LTP Chapter 6, section 6.6.1.

Penetrations also interfaced between the Turbine Building and the Auxiliary Building, primarily through the G wall but also through the north and south walls into the Unit 1 and Unit 2 Steam Tunnels, as well as both Unit 1 and Unit 2 Containments, through the Unit 1 and Unit 2 Main Steam Valve Houses. LTP Chapter 6, section 6.4.5 states, The dose from penetrations is summed with the dose from the wall and floor surfaces of both basements that the penetration interface. The FSS of the Turbine Building penetrations that interface with the Auxiliary Building is presented in the Release Record for the Auxiliary Building penetrations and, the FSS of the Turbine Building penetrations that interface with the Unit 1 and Unit 2 Containments are presented in the Release Records for the Unit 1 and Unit 2 Containment

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 penetrations. The FSS design employed the Operational DCGLs (OpDCGLPN) for the Auxiliary Building and Containments as they were the most limiting. However, the mean concentration for each Radionuclide-of-Concern (ROC) was compared against the Base Case Penetration DCGLs (BcDCGLPN) for the Turbine Building as well. The resultant dose from each was added to the Turbine Building dose to ensure compliance with the LTP.

When this survey commenced in March of 2016, it was performed at risk in accordance with the initial version of the LTP, which was not approved. The survey design for all three survey units utilized Basement Inventory Levels (BIL) as the Operational DCGLs had not yet been developed. The initial analysis of the FSS data was directly compared against the BILs to determine the Sum-of-Fractions (SOF) of individual measurements and to derive the values used for the Sign Test. In addition, other commitments from Revision 2 of the LTP, such as the requirement to acquire concrete core samples for HTD ROC analysis were not required at the time the surveys were performed. When compared against the BILs, all measurements taken for the FSS of these three survey units were less than a SOF of 0.5 and decommissioning decisions were made based upon those results. However, for this Release Record, the measurement results taken in 2016 were compared against the Operational DCGLs from the approved Revision 2 of the LTP. As the Operational DCGLs are significantly more conservative than the BILs, several measurements exceeded a SOF of 0.5 when compared against the Operational DCGLs and several measurements exceeded a SOF of one. No measurements exceeded the Base Case DCGLs. In these cases, no investigations were performed as required by LTP Chapter 5, section 5.6.4.6 and, no assessment was made to determine if reclassification was appropriate was performed as required in accordance with LTP Chapter 5, section 5.6.4.6.1. By the time this discrepancy was identified, the Turbine Building basement void had been completely backfilled and additional investigations were not possible. In addition, it should also be noted that with the exception of the two measurements taken in the Unit 2 Discharge Tunnel, all measurements were less than a SOF of 0.5 when compared against the Base Case DCGLs. (BcSOF of 0.9411 and 0.6860). ZionSolutions believes that despite these differences in LTP Rev 0 vs Rev 2 compliance, sufficient measurements were acquired to adequately quantify the radiological source term that remains in the Turbine Building footprint and that the dose assigned is representative and conservative.

Upon discovery of these differences during preparation for this submittal, a Condition Report was initiated to document the issue and any corrective actions.

Of the 28 random and 173 judgmental measurements obtained in the Turbine Building, 2 judgmental ISOCS measurements taken in sumps exceeded a SOF of 0.5 when compared against the Operational DCGL for structures in the Turbine Building (OpDCGLB). One random measurement taken in the Unit 1 Steam Tunnel and two judgmental ISOCS measurements taken in the Unit 2 Circulating Water Discharge Tunnel exceeded a SOF of one when compared against the Operational DCGL.

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 The mean SOF for the Turbine Building basement when compared against the Operational DCGL (OpSOF) was 0.2455 with a maximum OpSOF of 1.3460. When compared against the Base Case DCGL for the Turbine Building (BcDCGLB), the mean BcSOF (area-weighted adjusted for the elevated measurement) for the Turbine Building basement was 0.0209, which results in the dose calculated for this survey unit to be 0.5233 mrem/yr.

The mean OpSOF for the Circulating Water Discharge pipe was 0.1459 with a maximum OpSOF of 0.4165. When compared against the BcDCGLB, the mean BcSOF for the Circulating Water Discharge Pipe was 0.0124, which results in the dose calculated for this survey unit to be 0.3097 mrem/yr.

The mean OpSOF for the Circulating Water Discharge Tunnels was 0.2852 with a maximum OpSOF of 2.2517. When compared against the BcDCGLB, the mean BcSOF for the Circulating Water Discharge Tunnels (area-weighted adjusted for the two elevated measurements) was 0.1272, which results in the dose calculated for this survey unit to be 3.1800 mrem/yr.

In accordance with LTP Chapter 6, section 6.6.8, the activity in the Circulating Water Intake Pipes, Circulating Water Discharge Tunnels, Circulating Water Discharge Pipes, Buttress Pits/Tendon Tunnels, Diesel Generator Rooms and Valve Houses are included with Turbine Building through the DCGL calculation. The activity in the Circulating Water Intake Pipe is conservatively assumed to be part of the Turbine Building and the Crib House/Forebay survey units simultaneously. Consequently, the area-weighted mean of the measurements in these survey units are added to the mean (BcSOF) of the Turbine Building results. The area-weighted adjusted mean BcSOF for the Turbine Building is 0.0459, which equates to a dose of 1.1470 mrem/yr.

It should be noted that prior to backfill, a confirmatory survey of the Turbine Building basement was performed by Oak Ridge Institute for Science and Education (ORISE) with no findings.

2. CLASSIFICATION BASIS Survey Units B3-06100, B3-09200B and S3-06105AS were classified in accordance with ZionSolutions procedure ZS-LT-300-001-002, Survey Unit Classification (Reference 6).

The Turbine Building and all systems within the Turbine Building were initially classified as a Class 2 structure by the Zion Station Historical Site Assessment (HSA) (Reference 7).

In November of 2012, Site Characterization of the Turbine Building commenced with the acquisition of a series of concrete core samples that were taken in the 560 foot elevation Turbine Building concrete floor as well as the 570 foot elevation Steam Tunnel concrete floors.

The locations where the core samples were taken are illustrated in Figure 1.

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 Figure 1 - Turbine Building Characterization Concrete Core Locations A total of 10 concrete core samples were collected, three (3) in the Turbine Building 560 foot elevation floor, five (5) in the Unit 1 Steam Tunnel floor and two (2) in the Unit 2 Steam Tunnel floor. The locations selected were biased toward locations where physical or observed radiological measurements indicated the presence of fixed and/or volumetric contamination of the concrete media. When possible, locations were determined based upon elevated observed contact dose rates or count rates. In addition, visual observations of floor and wall surfaces were used to identify potential locations of surface contamination, such as discoloration or standing water. The goal was to identify to the extent possible, the locations that exhibited the highest potential of representing the worst case radiological condition for concrete in each survey unit. A summary of the gamma spectroscopy results for the concrete cores obtained from the Turbine Building 560 foot elevation and the 570 foot elevation Steam Tunnels are provided in Table 1. Cs-137 was the only plant-derived gamma emitting radionuclides identified. Concentrations for Co-60 were less than the Minimum Detectable Concentration (MDC) for all samples from the Turbine Building and the Steam Tunnels.

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 Table 1 - Turbine Building 560 Foot and 570 Foot Elevation Concrete Core Sample Analysis Summary Co-60 Cs-137 Core Avg. Avg.

Surface Surface Location Sample ID Depth Subsurface Subsurface Activity (a) Activity (a)

(inches) Activity (b) Activity (b)

(pCi/g) (pCi/g) (pCi/g) (pCi/g)

TB 560 el. North @ Grid F8 B206104-CJFCCV-001 5.5 1.14E-01 8.57E-02 1.27E-01 1.30E-01 TB 560 el. North @ Grid F11 B206104-CJFCCV-002 5.0 2.11E-01 1.07E-01 1.65E+00 1.76E-01 TB 560 el. North @ Grid F12 B206104-CJFCCV-003 4.0 2.73E-01 1.10E-01 4.67E+00 1.37E+00 Unit 1 Steam Tunnel @ Grid L32 B206207-CJFCCV-001 2.0 1.04E-01 1.18E-01 4.67E+00 2.98E+00 Unit 1 Steam Tunnel @ Grid K31 B206207-CJFCCV-002 2.0 1.30E-01 6.86E-02 4.52E+01 3.02E+00 Unit 1 Steam Tunnel@ Grid M32 B206207-CJFCCV-003 2.0 1.06E-01 9.61E-02 1.49E+01 1.03E+00 Unit 1 Steam Tunnel o/s West Valve Room B206207-CJFCCV-004 2.0 1.66E-01 7.57E-02 3.97E+01 2.44E+00 Unit 1 Steam Tunnel @ End of Tunnel B206207-CJFCCV-005 1.5 6.56E-02 1.22E-01 1.74E+01 1.70E+00 Unit 2 Steam Tunnel o/s West Valve Room B206208-CJFCCV-001 2.0 1.50E-01 1.17E-01 6.72E+00 5.95E-01 Unit 2 Steam Tunnel o/s West Valve Room B206208-CJFCCV-002 5.0 1.35E-01 8.93E-02 1.86E+01 1.97E-01 (a) Represents surface activity of floor following removal of loose contamination (b) Represents average of activity over entire depth of core sample minus the surface activity (c) Italicized values indicate MDC value.

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 Analyses of the concrete core samples taken from the Turbine Building 560 foot elevation show the presence of Cs-137 at concentrations greater than the MDC of the instrument at two (2) of the three (3) sample locations, and only in the 1st 1/2-inch of concrete. Observed Cs-137 concentrations ranged from 1.65 pCi/g to 4.67 pCi/g. At depths greater than 1/2-inch, concentrations for Cs-137 was less than MDC. In the Steam Tunnels, Cs-137 concentrations in the 1st 1/2-inch on concrete ranged from 4.67 pCi/g to 45.2 pCi/g in Unit 1 and 6.72 pCi/g to 18.6 pCi/g in Unit 2. At depths greater than 1/2-inch, concentrations for Cs-137 was less than the MDC of the instrument used.

Between March 21, 2013 and March 27, 2013, additional characterization was performed in the Turbine Building. All accessible surfaces of the 560 foot elevation floor in the Turbine Building were scanned using a Ludlum Model 43-37 floor monitor. The average background of the instrument was 900 cpm. The alarm set-point was set at the observed background plus the Minimum Detectable Count Rate (MDCR) for the instrument. The mean observed count rate was 1,493 cpm with a maximum observed count rate of 3,922 cpm. Three (3) instrument alarms were observed, primarily around a posted radiological area adjacent to the elevator.

In accordance with the Basement Fill Model (BFM), the classification for the Turbine Building, Circulating Water Discharge Pipe and Circulating Water Discharge Tunnel survey units were changed from their original classification of Class 2 to Class 3 consistent with Section 5.5.2.1 of the LTP Chapter 5. The survey units and classifications designated for structures below 588 foot elevation from the HSA that were presented in LTP Chapter 2, Table 2-2 were based on screening values and source term assumptions that are significantly different from the BFM and were therefore not applicable. Process knowledge and the results of past radiological surveys and site characterization indicated that the probability of residual radioactivity in these FSS units exceeding 50% of the allowable inventory for the Turbine Building was very low.

During plant operations, the Circulating Water Discharge Tunnels were the main authorized effluent release pathway for the discharge of treated and filtered radioactive liquid effluent to Lake Michigan. The liquid effluent release pathway was monitored and the results presented in the annual Radiological Environmental Monitoring Program (REMP) report in accordance with the Off-site Dose Calculation Manual (ODCM). During decommissioning, the Unit 2 Circulating Water Discharge Tunnel was used as the authorized effluent release pathway from July 2013 to October 2015.

The FSS units for the basement of the Turbine Building, the Circulating Water Discharge Pipe and the Circulating Water Discharge Tunnel were designated as Class 3 as defined in MARSSIM, section 2.2 in that the FSS units were not expected to contain any residual radioactivity, or expected to contain levels of residual radioactivity at a small fraction of the DCGLs, based on site operating history and previous radiation surveys. The Turbine Building basement FSS unit would be subjected to an areal coverage commensurate with the guidance pertaining to Class 3 scan coverage as presented in MARSSIM, Table 5.9, which states that the

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 scan coverage guidance is judgmental. In this context, judgmental areal coverage was defined as sufficient ISOCS measurements to ensure that at least 1% of the surface area in the survey unit was subjected to FSS.

A FSS Engineer performed a visual inspection and walk-down of the survey unit on 04/14/2016 prior to performing FSS. The purpose of the walk-down was to assess the physical condition of the survey unit, evaluate access points and travel paths and identify potentially hazardous conditions. A final classification assessment was performed in accordance with procedure ZS-LT-300-001-002 as part of the survey design for FSS.

Based upon completion of Survey Unit Classification Basis for final classification, which included a review of the historical information, the results of the Characterization Survey data and, completion of a final Survey Unit Classification Worksheet, it was concluded that there was a low probability for the presence of residual radioactivity at concentrations greater than 50% of the allowable inventory, justifying a final survey unit classification of Class 3 for Survey Units B3-06100, B3-09200B and S3-06105AS.

3. SURVEY UNIT DESCRIPTION The Turbine Building basement survey unit is an impacted Class 3 basement FSS unit. A basement FSS unit is comprised of the combined internal wall and floor surfaces of each remaining building basement below the 588 ft. elevation following demolition. The Turbine Building footprint is located within Class 1 open land survey units L1-12205A, L1-12205B, L1-12205C, L1-12205D and L112205E.

The Turbine Building housed the steam turbines and generators for both reactor units as well as secondary steam systems, circulating water systems, lubrication and fuel oil systems and emergency diesel generators. The internal structures that supported the Condensers, Turbine and Generators are solid concrete below the 588 foot elevation. The Circulating Water Intake and Discharge pipes are embedded in concrete above the 560 foot elevation. The floors of the Unit 1 and Unit 2 Steam Tunnels are at the 570 elevation and the floors of the Unit 1 and Unit 2 Diesel Generator Oil Storage rooms are at the 567 foot elevation. The Turbine Building sits on top of the Circulating Water Discharge Tunnels. The floor of the Unit 1 and Unit 2 Turbine Building basement is at the 560 foot elevation and has a Common Area between them. The Unit 1 and 2 areas are mirror images of each other.

The Unit 1 and Unit 2 Circulating Water Discharge Pipe and Discharge Tunnels provided for the discharge of cooling water, primarily from the Main Condensers but also from ancillary system cooling systems to Lake Michigan. The Circulating Water Tunnels were also the main authorized effluent release path to Lake Michigan for the release of treated and filtered radioactive liquid effluent. The tunnels run under the Turbine Building where two 12 foot diameter Circulating Water Discharge pipes opens into the tunnels from above. The tunnels

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 dip down under the Circulating Water Intake Pipes and then up again to the Valve House where it connects to the 14 foot diameter tunnels to Lake Michigan.

Large component removal in the Turbine Building was completed in 2015. Initial component removal included the dismantlement and removal of most of the large components, including the turbines, generator, moisture separator reheaters, feedwater heaters and coolers. In parallel with this effort, the surveys were performed for the unconditional release of materials, equipment and structural surfaces throughout the building.

All systems and materials that were identified by radiological survey as contaminated with detectable plant-derived radioactive material were removed and properly disposed of as radioactive waste. The remaining structure and materials in the Turbine Building were surveyed to demonstrate compliance with the unconditional release criteria. All remaining commodities were removed from the Turbine Building basement with the exception of the underground Circulating Water pipe, Circulating Water Discharge Tunnels, and buried Service Water pipe running between the Crib House location and the Auxiliary Building beneath the Turbine Building concrete floor.

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 Figure 2 - Turbine Building Basement 560 ft. Elevation

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 Figure 3 - Turbine Building Basement North

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 The Turbine Building structure was demolished to a depth of 3 feet below grade in accordance with the requirements of the Asset Sale Agreement. The Circulating Water Intake Piping, Circulating Water Discharge Pipe were filled with grout and the Intake/Discharge pipe and Discharge Tunnels were abandoned in place. Following the performance of FSS (as detailed in this Release Record) and a confirmatory survey by ORISE, the Turbine Building void was backfilled using clean concrete debris and clean fill from off-site to the 588 foot elevation.

Figure 4 - Turbine Building Demolition

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100

4. DATA QUALITY OBJECTIVES (DQO)

Final Status Survey planning and design hinges on coherence with the Data Quality Objective (DQO) process to ensure, through compliance with explicitly defined inputs and boundaries, that the primary objective of the survey is satisfied. The DQO process is described in the ZSRP LTP in accordance with MARSSIM. The appropriate design for a given survey will be developed using the DQO process as outlined in Appendix D of MARSSIM.

The DQO process incorporated hypothesis testing and probabilistic sampling distributions to control decision errors during data analysis. Hypothesis testing is a process based on the scientific method that compares a baseline condition to an alternate condition. The baseline condition is technically known as the null hypothesis. Hypothesis testing rests on the premise that the null hypothesis is true and that sufficient evidence must be provided for rejection. In designing the survey plan, the underlying assumption, or null hypothesis was that residual activity in the survey unit exceeded the release criteria. Rejection of the null hypothesis would indicate that residual activity within the survey unit does not exceed the release criteria.

Therefore, the survey unit would satisfy the primary objective of the FSS sample plan.

The primary objective of the FSS sample plan is to demonstrate that the level of residual radioactivity in Survey Units B3-06100, B3-09200B and S3-06105AS did not exceed the release criteria specified in the LTP and that the potential dose from residual radioactivity is As Low As Reasonably Achievable (ALARA).

ZionSolutions TSD 11-001, Potential Radionuclides of Concern during the Decommissioning of Zion Station (Reference 8) established the basis for an initial suite of potential ROC for the decommissioning of the Zion Nuclear Power Station (ZNPS). LTP Chapter 2 provides detailed characterization data that described contamination levels in the basements. The survey data for basements is based on core samples obtained at biased locations with elevated contact dose rates and/or evidence of leaks/spills and analyzed for the presence of plant-derived radionuclides. ZionSolutions TSD 14-019, Radionuclides of Concern for Soil and Basement Fill Model Source Terms (Reference 9) evaluates the results of the concrete core analysis data from the Containments and Auxiliary Building and refines the initial suite of radionuclides potential ROC by evaluating the dose significance of each radionuclide.

LTP Chapter 6, section 6.5.2 discusses the process used to derive the ROC for the decommissioning of ZNPS, including the elimination of insignificant dose contributors (IC) from the initial suite. Based upon the analysis of the mixture, it was determined that Co-60, Ni-63, Sr-90, Cs-134 and Cs-137 accounted for 99.5% of all dose in the non-activated contaminated concrete mixes.

Due to absence of significant source term in the Turbine Building, the suite of ROC and radionuclide mixture derived for the Auxiliary Building concrete was considered as a

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 reasonable conservative mixture to apply to the Turbine Building for FSS planning and implementation. Table 2 reproduces the ROC from LTP Chapter 5, Table 5-2.

Table 2 - Dose Significant Radionuclides and Mixture Auxiliary Building Radionuclide  % of Total Activity (normalized)(1)

Co-60 0.92%

Ni-63 23.71%

Sr-90 0.05%

Cs-134 0.01%

Cs-137 75.32%

(1) Based on maximum percent of total activity from Table 20 of TSD 14-019, normalized to one for the dose significant radionuclides.

A fundamental precursor to survey design is to establish a relationship between the release criteria and some measurable quantity. This is done through the development of DCGLs. The DCGLs represent average levels of radioactivity above background levels and are presented in terms of surface or mass activity concentrations. Chapter 6 of the LTP describes in detail the modeling used to develop the DCGLs for structures.

The End State Basements will be comprised of steel and/or concrete structures which will be covered by at least three feet of clean soil and physically altered to a condition which would not realistically allow the remaining structures, if excavated, to be occupied. The exposure pathways in the BFM are associated with residual radioactivity in floors and walls that is released through leaching into water contained in the interstitial spaces of the fill material. The BFM assumes that the inventory of residual radioactivity in a given building is released either instantly or over time by diffusion, depending on whether the activity is surficial or volumetric, respectively. The activity released into the fill water will adsorb onto the clean fill, as a function of the radionuclide-specific distribution coefficients, resulting in equilibrium concentrations between the fill and the water. Consequently, the only potential exposure pathways after backfill, assuming the as-left geometry, are associated with the residual radioactivity in the water contained in the fill.

The final outputs of the BFM are the Basement Derived Concentration Guideline Levels (DCGL), in units of pCi/m2, which are calculated using the BFM Groundwater (GW) and BFM Drilling Spoils Dose Factors. DCGLs are calculated separately for the GW and Drilling Spoils scenarios and for the summation of both scenarios. The summation DCGL is designated as the Base Case DCGL and is used during FSS to demonstrate compliance (analogous to the DCGLW as defined in MARSSIM). The Base Case DCGLs are radionuclide-specific concentrations that

[19]

FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 represent the 10 CFR 20.1402 dose criterion of 25 mrem/yr and are calculated for each ROC and each backfilled basement.

When applied to structures, the DCGLs are expressed in units of activity per unit of area (pCi/m2). The unity rule is applied when there is more than one ROC. The measurement results for each singular ROC present in the mixture are compared against their respective DCGL to derive a dose fraction.

The Base Case DCGLs for the unrestricted release of the Turbine Building Basement survey unit are provided in Table 3. The IC dose percentage of 5% was used to adjust the Turbine Building Basement DCGLs to account for the dose from the eliminated IC radionuclides.

Table 3 - Base Case DCGLs (BcDCGLB) for the Turbine Building Basement Survey Unit - LTP Chapter 5, Table 5-3 Base Case DCGL Turbine Building Floors Radionuclide and Walls (pCi/m2)

Co-60 7.03E+07 Ni-63 2.18E+09 Sr-90 7.74E+05 Cs-134 1.59E+07 Cs-137 2.11E+07 Each radionuclide-specific Base Case DCGL is equivalent to the level of residual radioactivity (above background levels) that could, when considered independently, result in a Total Effective Dose Equivalent (TEDE) of 25 mrem per year to an Average Member of the Critical Group (AMCG). To ensure that the summation of dose from each source term is 25 mrem/yr or less after all FSS is completed, the Base Case DCGLs are reduced based on an expected, or a priori, fraction of the 25 mrem/year dose limit from each source term. The reduced DCGLs, or Operational DCGLs can be related to the Base Case DCGLs as an expected fraction of dose based on an a priori assessment of what the expected dose should be based on the results of site characterization, process knowledge and the extent of planned remediation. The Operational DCGL is then used as the DCGL for the FSS design of the survey unit (calculation of surrogate DCGLs, investigations levels, etc.). Details of the Operational DCGLs derived for each dose component and the basis for the applied a priori dose fractions are provided in TSD 17-004, Operational Derived Concentration Guideline Levels for Final Status Survey (Reference 10).

The Operational DCGLs for the unrestricted release of the Turbine Building Basement survey unit are provided in Table 4.

[20]

FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 Table 4 - Operational DCGLs (OpDCGLB) for the Turbine Building Basement Survey Unit - LTP Chapter 5, Table 5-4 Operational DCGL Operational DCGL Turbine Building Floors Circulating Water and Walls Discharge Tunnel Radionuclide Circulating Water (pCi/m2)

Discharge Pipe (pCi/m2)

Co-60 5.98E+06 2.94E+07 Ni-63 1.85E+08 9.11E+08 Sr-90 6.58E+04 3.24E+05 Cs-134 1.35E+06 6.65E+06 Cs-137 1.79E+06 8.82E+06 Instrument DQOs included a verification of the ability of the survey instrument to detect the radiation(s) of interest relative to the Operational DCGL. The Canberra ISOCS was selected as the primary instrument used to perform FSS of basement surfaces. Survey instrument response checks were required prior to issuance and after the instrument had been used. Control and accountability of survey instruments was required to assure the quality and prevent the loss of data.

As part of the DQOs applied to laboratory processes, analysis results were reported as actual calculated results. The actual recorded value was used as the recorded FSS result for measurement and/or sample values that are less than MDC. Negative values were recorded as zero. Results were not reported as less than MDC. Sample report summaries included unique sample identification, analytical method, radionuclide, result, uncertainty, laboratory data qualifiers, units, and the observed MDC.

In accordance with the LTP, for laboratory analysis, MDCs less than 10% of the Operational DCGL were preferable while MDCs up to 50% of the Operational DCGL were acceptable.

The maximum acceptable MDC for measurements obtained using field instruments was 50 percent of the applicable Operational DCGL.

5. SURVEY DESIGN The level of effort associated with planning a survey is based on the complexity of the survey and nature of the hazards. Guidance for preparing FSS plans is provided in procedure ZS-LT-300-001-001.

During FSS, concentrations for Hard-to-Detect (HTD) ROC Ni-63 and Sr-90 are inferred using a surrogate approach. Cs-137 is the principle surrogate radionuclide for Sr-90 and Co-60 is the

[21]

FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 principle surrogate radionuclide for Ni-63. The mean, maximum and 95% Upper Confidence Level (UCL) of the surrogate ratios for concrete core samples taken in the Auxiliary Building basement were calculated in TSD 14-019 and are presented in Table 5. The maximum ratios will be used in the surrogate calculations during this FSS. Equations 1 through 3 show the results of the calculations. The results of the surrogate calculations are listed in Table 6.

Table 5 - Surrogate Ratios Auxiliary Building Ratios Mean Max 95%UCL Ni-63/Co-60 44.143 180.450 154.632 Sr-90/Cs-137 0.001 0.002 0.002 The equation for calculating a surrogate DCGL is as follows:

Equation 1 1

=

1 2 3

+ + +

2 3 Using the Operational DCGLs presented in Table 4 and the maximum ratios from Table 5, the following surrogate calculations were performed:

Equation 2 (Cs-137 Surrogate OpDCGL) 1 (137) = = 1.7006 /2 1 0.002

+

1.7906(137) 6.5804(90)

Equation 3 (Co-60 Surrogate OpDCGL) 1 (60) = = 8.7505 /2 1 180.45

+

5.9806(060) 1.8508(63)

Table 6 - Surrogate Operational DCGLs for Turbine Building Surrogate OpDCGL, Surrogate OpDCGL, Floors and Walls, Circ. Water Discharge Radionuclide Circulating Water Tunnel Discharge Pipe pCi/m2 pCi/m2 Co-60 8.75E+05 4.31E+06 Cs-137 1.70E+06 8.36E+06

[22]

FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 The action level for investigation in a Class 3 basement structure survey unit is 50% of the Operational DCGL. For the Turbine Building, the surrogate DCGL for Co-60 while inferring Ni-63 is 8.75E+05 pCi/m2 and the surrogate DCGL for Cs-137 while inferring Sr-90 is 1.70E+06 pCi/m2. The action levels for Survey Unit B3-06100 are based on 50% of the DCGL and are presented in Table 7.

Table 7 - Action Levels for Turbine Building Radionuclide Action Levels Floors and Walls, Circ. Water Circulating Water Discharge Tunnel Discharge Pipe (pCi/m2) (pCi/m2)

Co-60 4.38E+05 2.16E+06 Cs-134 6.75E+05 3.33E+06 Cs-137 8.49E+05 4.18E+06 The Sign Test was selected as the non-parametric statistical test. The use of the Sign Test did not require the selection or use of a background reference area, which simplified survey design and implementation. This approach was conservative since it included background Cs-137 as part of the sample set.

The Elevated Measurement Comparison (EMC) did not apply to this survey unit. At the ZSRP, EMC only applies to soils as all other media (structural surfaces, embedded pipe, buried pipe and penetrations) will be remediated to their applicable Base Case DCGL. In addition, Survey Units B3-06100, B3-09200B and S3-06105A are Class 3 basement survey units and discrete, elevated areas of contamination were not expected.

Sample size determination for FSS of basement surfaces is addressed in LTP Chapter 5, section 5.5.2.2. To ensure that the number of ISOCS measurements based on the necessary areal coverage in a basement surface FSS unit was sufficient to satisfy a statistically based sample design, a calculation was performed to determine sample size. If the sample size based on the statistical design required more ISOCS measurements than the number of ISOCS measurement required by the areal coverage, then the number of ISOCS measurements was adjusted to meet the larger sample size.

Following the guidance in MARSSIM, the Type I decision error that was used for this calculation was set at 0.05 and the Type II decision error was set at 0.05. The Upper Boundary of the Gray Region (UBGR) was set at the Operational DCGLB. The Lower Bound of the Gray Region (LBGR) was set at the expected fraction of the Operational DCGLB. The expected fraction of the Operational DCGLB in a Class 3 FSS basement unit was set at 1%. The standard deviation of the concrete core samples taken in the Turbine Building was used for sigma ().

[23]

FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 The relative shift (/) was calculated as discussed in LTP Chapter 5, section 5.6.4.1.6. The relative shift (/) for the survey unit data set is defined as shift (), which is the Upper Boundary of the Gray Region, or the Operational DCGLB (SOF of 1) minus the Lower Bound of the Gray Region (LBGR) (SOF of 0.01), divided by sigma (), which is the standard deviation of the data set used for survey design. The optimal value for / should range between 1 and 3. The largest value the / can have is 3. If the / exceeds 3, then the value of 3 will be used for /. The / for Survey Unit B3-06100, based on standard deviation of 15.66 for Cs-137 resulted in a / that was greater than three. Consequently, a value of three was used as the adjusted relative shift (/). From Table 5-5 of MARSSIM, the required number of measurements (N) for use with the Sign Test, using a value of 0.05 for the Type I and Type II decision errors, is fourteen (14) measurements for a / value of three.

Consequently, the number of ISOCS measurements in Turbine Building basement surface FSS unit was adjusted to meet the larger sample size. Table 8 presents the Turbine Building basement surface FSS units from LTP Chapter 5, Table 5-19 and the adjusted number of ISOCS measurements required.

Table 8 - Adjusted Minimum Number of ISOCS Measurements Required Adjusted # of Adjusted Adjusted Areal ISOCS Areal Areal FSS Unit Classification Coverage Measurements Coverage Coverage (m2) (FOV-28 m2) (m2) (% of Area)

Turbine Building Class 3 149 14 392 3%

Basement Circulating Water Class 3 49 14 392 8%

Discharge Tunnels A Retrospective Power Curve was generated using MARSSIM Power, a software package developed for implementation in support of the decommissioning license termination rule (10CFR20, Subpart E). The result of the MARSSIM Power program computer run showed adequate power for the survey design (see Attachment 2). The survey design specified fourteen (14) ISOCS measurements for non-parametric statistical testing.

As the survey unit was classified as Class 3, measurement locations were selected at random.

The random locations of the ISOCS measurements were selected using Visual Sample Plan (VSP), in accordance with ZS-LT-300-001-001. Input parameters included use of a grid layout and the random sampling tool set with a predetermined number (14) of measurement points.

Measurement locations for the ISOCS measurements taken for survey design are listed with the grid coordinates in Table 9. A map of the random ISOCS measurement locations for the Turbine Building basement is provided in Figure 1 in Attachment 1.

[24]

FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 Table 9 - Random ISOCS Measurement Locations for Turbine Building Structures Coordinates MEASUREMENT ID X-Axis Y-Axis B3-06100A-FRWC-01-GD 295.63 252.07 B3-06100A-FRWC-02-GD 449.65 -135.25 B3-06100A-FRFC-03-GD 141.60 37.94 B3-06100A-FRWC-04-GD 757.71 213.14 B3-06100A-FRWC-05-GD 64.59 271.54 B3-06100A-FRWC-06-GD 584.43 216.02 B3-06100A-FRWC-07-GD 45.33 -114.9 B3-06100A-FRFC-08-GD 314.88 21.36 B3-06100A-FQWC-09-GD 468.91 254.96 B3-06100A-FRWC-09-GD 468.91 254.96 B3-06100A-FRWC-10-GD 160.85 -244.68 B3-06100A-FRFC-11-GD 545.92 47.31 B3-06100A-FRFC-12-GD 112.72 66.78 B3-06100A-FRFC-13-GD 343.76 -30.55 B3-06100A-FRWC-14-GD 305.25 -238.19 In addition to the random measurements, an additional 16 ISOCS measurements were taken at judgmental locations. The selection of these locations was based upon the results of past operational and characterization surveys which provided indication that these areas had a higher probability for the presence of residual radioactivity. Measurement locations for the ISOCS measurements taken at judgmental locations are listed in Table 10. A map of the judgmental ISOCS measurement locations taken in the Turbine Building basement is provided in Figure 1 in Attachment 1.

[25]

FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 Table 10 - Judgmental ISOCS Measurement Locations for Turbine Building Structures MEASUREMENT ID LOCATION B3-06100A-FJWC-15-GD C/D Oil Room East Wall B3-06100A-FJWC-16-GD C/D Oil Room North Wall B3-06100A-FJWC-17-GD Unit 1 510 ft. Valve Pit B3-06100A-FJWC-18-GD Unit 2 510 ft. Valve Pit B3-06100A-FJFC-19-GD Elevator Sump Floor B3-06100A-FJFC-20-GD Unit 1 Eq. Drain Sump B3-06100A-FJWC-21-GD Unit 2 Eq. Drain Sump B3-06100A-FJFC-22-GD Unit 2 CW Surge Line B3-06100A-FJFC-23-GD Unit 1 Col. G-27 B3-06100A-FJFC-24-GD Unit 1 Col. G-25 B3-06100A-FJFC-25-GD Central Floor Drain Sump B3-06100A-FJFC-26-GD Central Fire Sump B3-06100A-FJWC-27-GD Central Fire Sump B3-06100A-FJWC-28-GD EVS 1 B3-06100A-FIWC-30-GD EVS 2 B3-06100A-FIWC-31-GD EVS 1 The area of floors and walls of the Unit 1 and Unit 2 Steam Tunnels are also part of Survey Unit B3-06100. Fourteen (14) additional ISOCS measurement locations were selected at random on the walls and floors of the Steam Tunnels. The random locations of the ISOCS measurements were selected using Visual Sample Plan (VSP), in accordance with ZS-LT-300-001-001. Input parameters included use of a grid layout and the random sampling tool set with a predetermined number (14) of measurement points. These 14 measurements were added to the 14 measurements taken on the 560 foot elevation of the Turbine Building resulting in a population of 28 measurements. Measurement locations for the ISOCS measurements taken for survey design in Unit 1 and Unit 2 Steam Tunnels are listed in Table 11. A map of the random ISOCS measurement locations for the Turbine Building basement is provided in Figure 3 in Attachment 1.

[26]

FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 Table 11 - Random ISOCS Measurement Locations for Unit 1 and Unit 2 Steam Tunnels MEASUREMENT ID LOCATION B3-06100B-FRFC-007-GD Floor B3-06100B-FRFC-008-GD Floor B3-06100B-FRWC-009-GD North Wall B3-06100B-FRWC-010-GD North Wall B3-06100B-FRWC-011-GD South Wall B3-06100B-FQWC-011-GD South Wall B3-06100B-FRWC-012-GD South Wall B3-06100B-FRWC-013-GD South Wall B3-06100B-FRWC-014-GD South Wall B3-06100B-FRWC-015-GD South Wall B3-06100B-FRWC-016-GD North Wall B3-06100B-FRWC-017-GD North Wall B3-06100B-FRWC-018-GD North Wall B3-06100B-FRWC-019-GD North Wall B3-06100B-FRFC-020-GD Floor In addition to the random measurements, an additional 8 ISOCS measurements were taken at judgmental locations in the Steam Tunnels. The selection of these locations was based upon the results of past operational and characterization surveys which provided indication that these areas had a higher probability for the presence of residual radioactivity. Measurement locations for the ISOCS measurements taken at judgmental locations in the Steam Tunnels are listed in Table 12. A map of the judgmental ISOCS measurement locations taken in the Steam Tunnels is provided in Figure 2 in Attachment 1.

[27]

FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 Table 12 - Judgmental ISOCS Measurement Locations for Unit 1 and Unit 2 Steam Tunnels MEASUREMENT ID LOCATION B3-06100B-FJWC-001-GD Unit 1 North east wall B3-06100B-FJWC-002-GD Unit 1 South east wall B3-06100B-FJFC-003-GD Unit 1 Floor B3-06100B-FJWC-004-GD Unit 2 North east wall B3-06100B-FJWC-005-GD Unit 2 South east wall B3-06100B-FJFC-006-GD Unit 2 Floor B3-06100B-FJWC-021-GD Unit 2 West Wall B3-06100B-FJWC-022-GD Unit 1 North Wall Revision 2 of ZSRP LTP Chapter 5, section 5.1 states that concrete core samples will be collected during FSS to confirm the HTD to surrogate radionuclide ratios. The FSS of the Turbine Building basement walls and floors was completed prior to issuance of Revision 2 of the LTP, when this commitment was made. The basement below the 588 ft. elevation has been backfilled and is no longer accessible. Therefore, no concrete core samples were acquired during FSS. However, as previously stated, ZionSolutions acquired and analyzed 10 concrete core samples during site characterization. Only Cs-137 was positively identified at detectable concentrations in these samples and at very low concentrations. In addition, 4 concrete core samples were acquired during the FSS of the Unit 1 and Unit 2 Diesel Fuel Oil Storage Tank Rooms on the Turbine Building 570 foot elevation. Those samples were analyzed for the HTD ROC. The results of those samples are addressed in the Release Records for, Unit 1 and Unit 2 Diesel Fuel Oil Storage Tank Rooms which are attached as Appendixes to this Release Record.

Fourteen (14) ISOCS measurements were required for the survey of the Unit 1 and Unit 2 Circulating Water Discharge Tunnels. Access to the Circulating Water Discharge Tunnels is very limited and therefore, these areas were surveyed as biased areas using judgmental measurements. Sample plan B3-09200B was generated for the acquisition of the judgmental ISOCS measurements in these tunnels.

In March of 2016, the Circulating Water Tunnels were drained and surveyed. Continuing characterization was combined with FSS due to the low levels of residual radioactivity that was expected to remain. Judgmental FSS measurements using the ISOCS were located on surfaces within the Tunnels that could be accessed safely. Measurement locations for the judgmental ISOCS measurements are listed with the grid coordinates in Table 13. A map of the

[28]

FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 judgmental ISOCS measurement locations for the Circulating Water Discharge Tunnels is provided in Figure 3 in Attachment 1.

Table 13 - Judgmental ISOCS Measurement Locations for Circulating Water Discharge Tunnels Coordinates MEASUREMENT ID X-Axis Y-Axis B3-09200B-FJCC-001-GD 7.3 0.64 B3-09200B-FJWC-002-GD 153.1 11.6 B3-09200B-FJFC-003-GD 9.1 331.1 B3-09200B-FRWC-004-GD 16.57 -61.20 B3-09200B-FJFC-005-GD 9.0 327.0 B3-09200B-FRWC-006-GD 58.48 -110.95 B3-09200B-FJWC-007-GD -147.8 10.8 B3-09200B-FJCC-008-GD 9.0 327.0 B3-09200B-FJCC-009-GD 23.1 252.5 B3-09200B-FJFC-010-GD 9.2 66.7 B3-09200B-FJWC-011-GD -31.3 4.4 B3-09200B-FJWC-012-GD -142.8 10.8 B3-09200B-FJFC-013-GD 16.7 4.5 B3-09200B-FJFC-014-GD 8.9 327.2 The survey unit for the Circulating Water Discharge Pipes consisted of the 48-inch ID crossover sections of both Unit 1 and Unit 2. On the 560 foot elevation of the Turbine Building, there were two (2) 510 Valve Pits that housed the 48-inch diameter Circulating Service Water Discharge Pipes. The 510 valve was removed from the Unit 1 and Unit 2 pit, leaving the 48-inch Circulating Service Water Discharge Pipes exposed. The 48-inch pipe was cut leaving the north and south section of the pipe open for survey as shown in Figure 5.

[29]

FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 Figure 5 - 510 Valve Pit Circulating Service Water Discharge Pipe The FSS survey consisted of 2 judgmental ISOCS measurements in each pipe opening, one to the north and one to the south. The interior of both pipes had a surface area of 760 m2, but the only accessible portions of the pipe were the sections open to the Valve Houses. Judgmental ISOCS measurement locations are listed in Table 14.

Table 14 - Judgmental ISOCS Measurement Locations for Circulating Water Discharge Pipe MEASUREMENT ID LOCATION B3-06105A-FJSM-001-GD Unit 1 North Section B3-06105A-FJSM-002-GD Unit 1 South Section B3-06105A-FJSM-003-GD Unit 2 North Section B3-06105A-FJSM-004-GD Unit 2 South Section A map of the judgmental ISOCS measurement locations for the Circulating Water Discharge Pipes is provided in Figure 3 in Attachment 1.

The implementation of quality control measures as referenced by LTP Chapter 5, section 5.9 and ZionSolutions ZS-LT-01, Quality Assurance Project Plan (for Characterization and FSS) (QAPP) (Reference 11) includes the collection of a replicate measurement at 5% of the locations selected at random. One ISOCS measurement, B3-06100A-FQWC-09-GD was selected randomly for the replicate measurement for the Turbine Building basement. One

[30]

FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 ISOCS measurement, B3-06100B-FQWC-011-GD was selected randomly for the replicate measurement for the Unit 1 and Unit 2 Steam Tunnels. An additional replicate ISOCS measurement, B3-09200B-FQCC-009-GD was selected for the judgmental measurements taken in the Circulating Water Discharge Tunnel.

The areal coverage requirements for FSS of structures as specified in the LTP is commensurate with the probability that a small area of elevated activity could exist within a FSS unit in a concentration exceeding the Base Case DCGL and the likelihood that such an area would not be detected by the FSS ISOCS measurements. It is highly unlikely that the ISOCS, with a nominal Field-of-View (FOV) of approximately 28 m2 would not detect and account for elevated areas. The primary basis used to determine reasonable areal coverage for the ISOCS measurements is the potential for the Operational DCGL to be exceeded. The criterion for selecting reasonable and risk-informed areal coverage is based on a graded approach similar to the guidance for scan surveys during FSS provided in MARSSIM, where the coverage is based on the expected fraction of the DCGL (in this case, Operational DCGL).

As a Class 3 survey unit, LTP Chapter 5, Table 5-19, reproduced as Table 8 specifies that a minimum of 392 m2 or 3% of the accessible surface area in the Turbine Building structural basement survey unit will be subjected to scan coverage. The surface area covered by a single ISOCS measurement is large (a nominal range of 10-30 m2), and the FOV of the measurement becomes a substitute for scanning that is typically performed by moving a 100cm2 hand-held detector over the surface in question. Twenty-eight (28) ISOCS measurements were taken of the Turbine Building and Steam Tunnel basement surfaces, representing an areal coverage of 792 m2. In addition, 24 judgmental ISOCS measurements were taken in the Turbine Building basement and Steam Tunnels, providing for another 799 m2 of areal coverage. Four judgmental measurements were also taken in the Circulating Water Discharge Pipe, which is included with the surface area of the Turbine Building. Those measurements add an addition 113 m2 to the areal coverage. The total areal coverage of the FSS performed of the Turbine Building basement and Steam Tunnels, including the Circulating Water Discharge Pipe was 1,704 m2 or 6.3%, which is far in excess of the areal coverage requirements stated in LTP Chapter 5, Table 5-19. Table 8 also specifies that a minimum of 392 m2 or 8% of the accessible surface area in the Circulating Water Discharge Tunnel survey unit will be subjected to scan coverage. The 14 judgmental measurements provided 396 m2 of areal coverage, again in excess of the areal coverage requirements stated in LTP Chapter 5, Table 5-19. For these basement survey units, the Investigation Levels are those levels specified in LTP Chapter 5, Table 5-25 and are reproduced below in Table 15.

[31]

FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 Table 15 - Investigation Levels Classification Direct Measurement Class 1 >Operational DCGLW Class 2 >Operational DCGLW Class 3 >0.5 Operational DCGLW Table 16 provides a synopsis of the survey design for Survey Units B3-06100, B3-09200B and S3-06105A.

[32]

FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 Table 16 - Synopsis of Survey Design DESIGN BASIS FEATURE Survey Unit B3- Survey Unit B3- Survey Unit S3- BASIS 06100 09200B 06105A 27,135 m2 (LTP Chapter 6, Tables 6-22 and Survey Unit Area 4,868 1,075 (total area incl. all areas) 6-23) 28 Random, Number of Measurements 14 Judgmental 4 Judgmental (LTP Chapter 5, Table 5-19) 24 Judgmental Measurement Spacing Random Biased Biased (LTP Chapter 5, Section 5.6.4)

• Co-60 5.98E+06

• Co-60 2.94E+07

• Co-60 5.98E+06 DCGLs

• Ni-63 1.85E+08

• Ni-63 9.11E+08

• Ni-63 1.85E+08 Operational DCGLs,

• Sr-90 6.58E+04

• Sr-90 3.24E+05

• Sr-90 6.58E+04 (pCi/m )2 (LTP Chapter 5, Table 5-4)

• Cs-134 1.35E+06

• Cs-134 6.65E+06

• Cs-134 1.35E+06

• Cs-137 1.79E+06

• Cs-137 8.82E+06

• Cs-137 1.79E+06 Measurement >0.5 Operational >0.5 Operational >0.5 Operational (LTP Chapter 5, Table 5-25)

Investigation Level DCGL DCGL DCGL Scan Survey Area (incl. with Turbine 392 m2 or 3% 392 m2 or 8% (LTP Chapter 5, Table 5-19)

Coverage Building Area)

QC 5% of measurement 5% of measurement N/A (LTP Chapter 5, section 5.9.3.1)

[33]

FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100

6. SURVEY IMPLEMENTATION Survey instructions for this FSS were incorporated into and performed in accordance with FSS Sample Plans B3-06100, Turbine Building, B3-09200B, Circulating Water Discharge Tunnels and S3-06105A, Unit 1 and Unit 2 Circulating Water Discharge Pipe, which were developed in accordance with ZionSolutions procedure ZS-LT-300-001-001. All FSS units were inspected and controlled in accordance with ZionSolutions procedure ZS-LT-300-001-003, Isolation and Control for Final Status Survey (Reference 12). Compliance with the unrestricted release criteria was demonstrated through direct measurements using the ISOCS.

FSS field activities commenced in the Turbine Building basement in March of 2016. A Field Log (ZS-LT-300-001-001 Attachment 14) was used to document field activities and other information pertaining to the performance of the FSS.

FSS field activities were projected to take twelve (12) working days to complete FSS in all three areas. Daily briefings were conducted to discuss the expectations for job performance and to review safety aspects of the job.

ZionSolutions TSD 14-022, Use of In-Situ Gamma Spectroscopy for Source Term Survey of End State Structures (Reference 13) provides the initial justification for the selection of reasonably conservative geometries for efficiency calibrations for the ISOCS based on the physical conditions of the remediated surface and the anticipated depth and distribution of activity. Prior to implementing the sample plan for the FSS of the Turbine Building basement structure and the Circulating Water Discharge Tunnel, the physical condition of the surfaces to be surveyed were assessed to ensure that the geometry was not significantly changed from that assumed in TSD 14-022. Most ISOCS measurements were acquired using the geometry labeled as TBFLOOR, which assumed a circular plane source with a contaminant depth of 1/2 inch. With the 90-degree collimation shield installed and a stand-off distance of 3 meters, this orientation corresponded to a nominal FOV of 28 m2. Other geometries were used where the physical configuration of the measurement was different than a circular plane. For example, unique geometries were used for measurements taken in valve boxes and sumps. Unique ISOCS geometries were also employed for the measurements taken in the Circulating Water Discharge Tunnels and Circulating Water Discharge Pipe. A stand-off guide attached to the detector was used to establish a consistent source to detector distance and center the detector over the selected measurement location. The details pertaining to ISOCS geometries are provided in Attachment 2.

The 28 random ISOCS measurement locations were marked based on grid coordinates provided by VSP. A replicate measurement was also acquired in the Turbine Building basement at location B3-06100A-FQWC-09-GD, B3-6100B-FQWC-011-GD and in the Circulating Water Discharge Tunnels at location B3-09200B-FQCC-009-GD.

[34]

FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100

7. SURVEY RESULTS Direct measurements were acquired at each random location in the Turbine Building and Steam Tunnels basement and at the selected judgmental locations in the Turbine Building basement, the Circulating Water Discharge Pipe and the Circulating Discharge Tunnels using the ISOCS.

A summary of the results of the 28 ISOCS measurements taken for non-parametric statistical testing results are provided in Table 17. The concentrations for Ni-63 and Sr-90 are inferred based on the maximum ratios as specified in Table 5. The complete ISOCS gamma spectroscopy reports are presented in Attachment 7.

The SOF or unity rule is the mathematical test used to evaluate compliance with radiological criteria for license termination when more than one radionuclide has been determined to be potentially present. The equation for the unity rule is:

Equation 4 C1 C2 Cn

+ +............ 1 DCGL1 DCGL 2 DCGL n Where: Cn = concentration of radionuclide n DCGLn = DCGL of radionuclide n.

The basic statistics for the random measurements are summarized in Table 18.

Table 17 - Summary of ISOCS Results for Random Measurements Co-60 Cs-134 Cs-137 Ni-63 Sr-90 MEASUREMENT ID OpSOF (pCi/m ) (pCi/m ) (pCi/m ) (pCi/m ) (pCi/m2) 2 2 2 2 B3-06100A-FRWC-001-GD 1.30E+04 1.60E+04 1.59E+04 2.35E+06 3.18E+01 0.0361 B3-06100A-FRWC-002-GD 1.34E+04 1.97E+04 1.80E+04 2.42E+06 3.60E+01 0.0405 B3-06100A-FRFC-003-GD 4.49E+03 6.34E+03 4.91E+03 8.10E+05 9.82E+00 0.0127 B3-06100A-FRWC-004-GD 1.43E+04 1.66E+04 1.89E+04 2.58E+06 3.78E+01 0.0398 B3-06100A-FRWC-005-GD 1.43E+04 1.80E+04 1.89E+04 2.58E+06 3.78E+01 0.0408 B3-06100A-FRWC-006-GD 1.15E+04 1.57E+04 2.07E+04 2.08E+06 4.14E+01 0.0370 B3-06100A-FRWC-007-GD 1.15E+04 1.93E+04 1.33E+04 2.08E+06 2.66E+01 0.0353 B3-06100A-FRFC-008-GD 6.68E+03 8.20E+03 9.02E+03 1.21E+06 1.80E+01 0.0190 B3-06100A-FRWC-009-GD 1.20E+04 1.66E+04 1.82E+04 2.17E+06 3.64E+01 0.0367 B3-06100A-FRWC-010-GD 1.47E+04 1.57E+04 1.75E+04 2.65E+06 3.50E+01 0.0387 B3-06100A-FRFC-011-GD 1.43E+04 1.75E+04 1.93E+04 2.58E+06 3.86E+01 0.0407

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 Table 17 (continued) - Summary of ISOCS Results for Random Measurements Co-60 Cs-134 Cs-137 Ni-63 Sr-90 MEASUREMENT ID OpSOF (pCi/m ) (pCi/m ) (pCi/m ) (pCi/m ) (pCi/m2) 2 2 2 2 B3-06100A-FRFC-012-GD 1.39E+04 1.97E+04 1.95E+04 2.51E+06 3.90E+01 0.0420 B3-06100A-FRFC-013-GD 1.20E+04 1.97E+04 2.28E+04 2.17E+06 4.56E+01 0.0417 B3-06100A-FRFC-014-GD 1.13E+04 1.69E+04 1.73E+04 2.04E+06 3.46E+01 0.0356 B3-06100B-FRFC-007-GD 1.53E+05 2.05E+05 2.00E+05 2.76E+07 4.00E+02 0.4445 B3-06100B-FRFC-008-GD 1.68E+05 2.14E+05 1.69E+06 3.03E+07 3.38E+03 1.3460 B3-06100B-FRWC-009-GD 1.47E+05 1.98E+05 1.95E+05 2.65E+07 3.90E+02 0.4295 B3-06100B-FRWC-010-GD 1.44E+05 1.97E+05 2.80E+05 2.60E+07 5.60E+02 0.4754 B3-06100B-FRWC-011-GD 1.58E+05 1.85E+05 1.97E+05 2.85E+07 3.94E+02 0.4336 B3-06100B-FRWC-012-GD 1.37E+05 7.71E+03 1.82E+05 2.47E+07 3.64E+02 0.2695 B3-06100B-FRWC-013-GD 1.49E+05 1.94E+05 2.33E+05 2.69E+07 4.66E+02 0.4512 B3-06100B-FRWC-014-GD 1.32E+05 1.64E+05 1.80E+05 2.38E+07 3.60E+02 0.3783 B3-06100B-FRWC-015-GD 1.32E+05 1.89E+05 1.85E+05 2.38E+07 3.70E+02 0.3998 B3-06100B-FRWC-016-GD 1.32E+05 1.85E+05 1.84E+05 2.38E+07 3.68E+02 0.3963 B3-06100B-FRWC-017-GD 1.73E+05 2.14E+05 1.95E+05 3.12E+07 3.90E+02 0.4711 B3-06100B-FRWC-018-GD 1.47E+05 1.76E+05 2.03E+05 2.65E+07 4.06E+02 0.4179 B3-06100B-FRWC-019-GD 1.32E+05 2.06E+05 1.98E+05 2.38E+07 3.96E+02 0.4201 B3-06100B-FRFC-020-GD 1.43E+04 1.95E+04 2.10E+04 2.58E+06 4.20E+01 0.0432 One measurement, B3-06100B-FRFC-008-GD, exceeded a SOF of one when compared against the Operational DCGLs for the Turbine Building. This measurement was taken on the floor in the Unit 1 Steam Tunnel at the entrance to the East Valve House. However, when compared against the BILs, the measurement presented a SOF of 0.0594. Consequently, no action or investigation was taken at the time the survey was performed in 2016. The BcSOF, when compared against the Base Case DCGLs for this individual measurement is 0.1142. The adjustment to the mean BcSOF from elevated measurement B3-06100B-FRFC-008-GD is 0.0001 (see Attachment 3).

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 Table 18 - Basic Statistical Properties of Random ISOCS Measurements Mean Median Max Min BcDCGL Avg. SOF Avg. Dose ROC Std. Dev.

(pCi/m2) (pCi/m2) (pCi/m2) (pCi/m2) (pCi/m2) per ROC Per ROC Co-60 7.45E+04 1.45E.04 1.73E+05 4.49E+03 6.89E+04 7.03E+07 0.0011 0.0265 Cs-134 9.21E+04 1.97E+04 2.14E+05 6.34E+03 9.03E+04 1.59E+07 0.0058 0.1449 Cs-137 1.56E+05 2.19E+04 1.69E+06 4.91E+03 3.15E+05 2.11E+07 0.0074 0.1852 Ni-63 1.34E+07 2.62E+06 3.12E+07 8.10E+05 1.24E+07 2.18E+09 0.0062 0.1541 Sr-90 3.13E+02 4.38E+01 3.38E+03 9.82E+00 6.30+02 7.74E+05 0.0004 0.0101 The mean BcSOF from random measurements taken on basement structural surfaces in Survey Unit B3-06100 is 0.0208. This is derived by summing the average SOF per ROC resulting from the average concentration in Table 18. The adjustment to the mean BcSOF from elevated measurement B3-06100B-FRFC-008-GD is 0.0001. The adjusted mean BcSOF for Survey Unit B3-06100 is 0.0209, which equates to a dose of 0.5233 mrem/yr.

The implementation of required QC measurements included the collection of three additional ISOCS measurement at location 9 (B3-06100A-FQWC-09-GD), 11 (B3-06100BFQWC-011-GD) and 9 (B30900B-FQCC-009-GD) for replicate measurements analysis. The replicate ISOCS measurement results are provided in Table 19. The concentration for Ni-63 and Sr-90 are inferred based on the maximum ratios as specified in Table 5.

Table 19 - Summary of ISOCS Replicate Measurement for QC Co-60 Cs-134 Cs-137 Ni-63 Sr-90 MEASUREMENT ID OpSOF (pCi/m ) (pCi/m ) (pCi/m ) (pCi/m ) (pCi/m2) 2 2 2 2 B3-06100A-FQWC-009-GD 1.53E+04 1.80E+04 1.59E+04 2.76E+06 3.18E+01 0.0034 B3-06100B-FQWC-011-GD 1.51E+05 1.75E+05 1.71E+05 2.72E+07 3.42E+02 0.0021 B3-09200B-FQCC-009-GD 1.04E+04 2.00E+04 1.95E+04 1.88E+06 3.90E+01 0.1059 Twenty-four (24) judgmental measurements were acquired in the Turbine Building basement and in the Unit 1 and Unit 2 Steam Tunnels. A summary of the results are provided in Table

20. The concentration for Ni-63 and Sr-90 are inferred based on the maximum ratios as specified in Table 5. The complete ISOCS gamma spectroscopy reports are presented in Attachment 7.

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 Table 20 - Summary of ISOCS Results for Judgmental Measurements Taken in the Turbine Building Basement and Steam Tunnels Co-60 Cs-134 Cs-137 Ni-63 Sr-90 MEASUREMENT ID OpSOF (pCi/m2) (pCi/m2) (pCi/m2) (pCi/m2) (pCi/m2)

B3-06100B-FJWC-015-GD 7.13E+03 9.62E+03 1.13E+04 1.29E+06 2.26E+01 0.0219 B3-06100B-FJWC-016-GD 4.44E+03 2.60E+04 4.67E+03 8.02E+05 9.34E+00 0.0271 B3-06100A-FJW-017-GD 0.00E+00 4.92E+04 8.06E+04 0.00E+00 1.61E+02 0.0839 B3-06100A-FJWC-018-GD 5.24E+03 4.53E+03 3.98E+04 9.46E+05 7.96E+01 0.0328 B3-06100A-FJFC-019-GD 0.00E+00 3.50E+04 0.00E+00 0.00E+00 0.00E+00 0.0260 B3-06100A-FJFC-020-GD 5.81E+04 2.07E+05 4.21E+05 1.05E+07 8.41E+02 0.4671 B3-06100A-FJWC-021-GD 2.22E+04 9.19E+04 3.23E+05 4.00E+06 6.46E+02 0.2836 B3-06100A-FJFC-022-GD 1.68E+04 1.69E+04 5.52E+04 3.03E+06 1.10E+02 0.0643 B3-06100A-FJFC-023-GD 1.28E+04 1.80E+04 3.27E+03 2.31E+06 6.53E+00 0.0299 B3-06100A-FJFC-024-GD 0.00E+00 1.57E+04 0.00E+00 0.00E+00 0.00E+00 0.0116 B3-06100A-FIFC-025-GD 1.31E+05 2.58E+05 9.34E+05 2.37E+07 1.87E+03 0.8913 B3-06100A-FJFC-026-GD 1.74E+04 1.75E+04 7.42E+04 3.14E+06 1.48E+02 0.0766 B3-06100A-FJWC-027-GD 2.85E+04 3.22E+04 2.56E+05 5.14E+06 5.11E+02 0.2070 B3-06100A-FJWC-028-GD 7.00E+02 1.36E+03 1.42E+05 1.26E+05 2.84E+02 0.0856 B3-06100A-FIWC-030-GD 1.37E+04 1.89E+04 1.89E+04 2.47E+06 3.78E+01 0.0408 B3-06100A-FIWC-031-GD 1.50E+04 1.74E+04 1.70E+05 2.71E+06 3.40E+02 0.1301 B3-06100B-FJWC-001-GD 1.62E+04 1.80E+04 5.65E+04 2.92E+06 1.13E+02 0.0055 B3-06100B-FJWC-002-GD 1.34E+04 2.18E+04 1.80E+04 2.42E+06 3.60E+01 0.0036 B3-06100B-FJFC-003-GD 4.67E+03 6.69E+03 7.24E+03 8.43E+05 1.45E+01 0.0012 B3-06100B-FJWC-004-GD 1.34E+04 2.09E+04 2.08E+04 2.42E+06 4.16E+01 0.0037 B3-06100B-FJWC-005-GD 1.43E+04 1.80E+04 1.84E+04 2.58E+06 3.68E+01 0.0034 B3-06100B-FJFC-006-GD 4.58E+03 6.02E+03 7.91E+03 8.26E+05 1.58E+01 0.0012 B3-06100B-FJWC-021-GD 1.49E+05 1.92E+05 1.87E+05 2.69E+07 3.74E+02 0.2680 B3-06100B-FJWC-022-GD 1.49E+05 1.85E+05 2.04E+05 2.69E+07 4.08E+02 0.2710 Of the 24 judgmental samples taken, one exceeded a SOF of 0.5 when compared against the Operational DCGLs. Measurement B306100AFIFC-025-GD, which was taken in the Floor Drain Sump, had an OpSOF of 0.8913. When compared against the BILs, the SOF for measurement B306100AFIFC-025-GD was 0.0393. Consequently, no action or investigation

[38]

FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 was taken at the time the survey was performed. When compared against the Base Case DCGLs, the BcSOF for measurement B306100AFIFC-025-GD was 0.0756.

Four (4) judgmental ISOCS measurements were taken within the Unit 1 and Unit 2 Circulating Water Discharge Pipe. A summary of the results of the 4 judgmental ISOCS measurements taken within the Circulating Water Discharge Pipe are provided in Table 21. The concentration for Ni-63 and Sr-90 are inferred based on the maximum ratios as specified in Table 5. The complete ISOCS gamma spectroscopy reports are presented in Attachment 7.

Table 21 - Summary of Gamma Spectroscopy Results for Judgmental ISOCS Measurements Taken in Circulating Water Discharge Pipes Co-60 Cs-134 Cs-137 Ni-63 Sr-90 MEASUREMENT ID OpSOF (pCi/m ) (pCi/m ) (pCi/m ) (pCi/m ) (pCi/m2) 2 2 2 2 B3-06105A-FJSM-001-GD 1.60E+04 1.15E+04 1.28E+04 2.89E+06 2.56E+01 0.0343 B3-06105A-FJSM-002-GD 9.20E+03 1.07E+04 1.25E+04 1.66E+06 2.50E+01 0.0258 B3-06105A-FJSM-003-GD 2.64E+05 5.49E+04 1.26E+05 4.76E+07 2.52E+02 0.4165 B3-06105A-FJSM-004-GD 2.63E+04 2.05E+04 1.05E+05 4.75E+06 2.10E+02 0.1071 In order to assess the dose contribution from the Circulating Water Discharge Pipe, the concentration of each ROC in each judgmental measurement was also compared against the respective Base Case DCGLs. The calculation of the mean BcSOF for the Circulating Water Discharge Pipe and the resultant dose is presented in Table 22.

Table 22 - Basic Statistical Properties of Judgmental ISOCS Measurements in Circulating Water Discharge Pipe Mean Median Max Min BcDCGL Avg. SOF Avg. Dose ROC Std. Dev.

(pCi/m2) (pCi/m2) (pCi/m2) (pCi/m2) (pCi/m2) per ROC Per ROC Co-60 7.89E+04 2.12E+04 2.64E+05 9.20E+03 1.24E+05 7.03E+07 0.0011 0.0280 Cs-134 2.44E+04 1.60E+04 5.49E+04 1.07E+04 2.08E+04 1.59E+07 0.0015 0.0384 Cs-137 6.41E+04 5.89E+04 1.26E+05 1.25E+04 6.00E+04 2.11E+07 0.0030 0.0759 Ni-63 1.42E+07 3.82E+06 4.76E+07 1.66E+06 2.23E+07 2.18E+09 0.0065 0.1632 Sr-90 1.28E+02 1.18E+02 2.52E+02 2.50E+01 1.20E+02 7.74E+05 0.0002 0.0041 The mean BcSOF from the judgmental measurements taken on the Circulating Water Discharge Pipe in Survey Unit S3-06105AS is 0.0124. This equates to a dose of 0.3097 mrem/yr. This is derived by summing the average SOF per ROC resulting from the average concentration in Table 22. There were no identified elevated areas.

Fourteen (14) judgmental ISOCS measurements were taken within the Unit 1 and Unit 2 Circulating Water Discharge Tunnels. A summary of the results of the 14 judgmental measurements are provided in Table 23. The concentration for Ni-63 and Sr-90 are inferred

[39]

FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 based on the maximum ratios as specified in Table 5. The complete ISOCS gamma spectroscopy reports are presented in Attachment 7.

Table 23 - Summary of Results for Judgmental Measurements Taken in the Circulating Water Discharge Tunnels Co-60 Cs-134 Cs-137 Ni-63 Sr-90 MEASUREMENT ID OpSOF (pCi/m2) (pCi/m2) (pCi/m2) (pCi/m2) (pCi/m2)

B3-09200B-FRCC-001-GD 1.66E+04 1.63E+04 1.99E+04 3.00E+06 3.98E+01 0.0087 B3-09200B-FRWC-002-GD 1.51E+04 1.69E+04 1.84E+04 2.72E+06 3.68E+01 0.0082 B3-09200B-FRFC-003-GD 1.08E+04 1.79E+04 1.42E+04 1.95E+06 2.84E+01 0.0069 B3-09200B-FRWC-004-GD 1.43E+04 1.77E+04 1.93E+04 2.58E+06 3.86E+01 0.0083 B3-09200B-FRFC-005-GD 9.51E+06 8.85E+04 2.66E+05 1.72E+09 5.32E+02 2.2517 B3-09200B-FRWC-006-GD 1.15E+04 1.83E+04 1.89E+04 2.08E+06 3.78E+01 0.0077 B3-09200B-FRWC-007-GD 2.59E+04 2.18E+04 2.10E+04 4.67E+06 4.20E+01 0.0118 B3-09200B-FRCC-008-GD 6.89E+06 7.40E+04 2.69E+05 1.24E+09 5.38E+02 1.6413 B3-09200B-FRCC-009-GD 1.43E+04 1.88E+04 1.82E+04 2.58E+06 3.64E+01 0.0083 B3-09200B-FRFC-010-GD 1.43E+04 1.88E+04 1.84E+04 2.58E+06 3.68E+01 0.0083 B3-09200B-FRWC-011-GD 1.22E+04 1.30E+04 1.96E+04 2.20E+06 3.92E+01 0.0071 B3-09200B-FRWC-012-GD 2.51E+04 2.11E+04 1.99E+04 4.53E+06 3.98E+01 0.0114 B3-09200B-FRFC-013-GD 1.34E+04 1.88E+04 1.68E+04 2.42E+06 3.36E+01 0.0079 B3-09200B-FRFC-014-GD 8.73E+03 1.08E+04 1.65E+04 1.58E+06 3.30E+01 0.0056 The Circulating Water Discharge Tunnels were the main authorized effluent release pathway for the discharge of treated and filtered radioactive liquid effluent to Lake Michigan. During plant operations and during decommissioning until the pathway was secured in October of 2015, the liquid effluent release pathway was monitored and the results presented in the annual REMP report in accordance with the ODCM. The release of effluent during decommissioning was made at the west end of the Discharge Tunnel in the steel lined area under the 12-foot diameter Down-comer pipes. Judgmental measurements B3-09200B-FRFC-005-GD and B3-09200B-FRCC-008-GD were taken on the floor under the Unit 2 Down-comer pipe where the effluent was released during decommissioning.

All FSS ISOCS measurements results in both Unit 1 and Unit 2 Circulating Water Discharge Tunnels were less than an OpSOF of 0.5 with the exception of the area under the Unit 2 Down-comer pipe. When compared against the Operational DCGLs, judgmental measurements B3-09200B-FRFC-005-GD and B3-09200B-FRCC-008-GD resulted in OpSOF of 2.2517 and 1.6413 respectively. Co-60 and Cs-137 were positively identified in both measurements.

[40]

FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 When compared against the BILs, both measurements presented a SOF of 0.4887 and 0.3562 respectively. Consequently, no action or investigation was taken at the time the survey was performed. The BcSOF for both measurements were 0.9411 and 0.6860 respectively. The adjustment to the mean BcSOF from elevated measurements B3-09200B-FRFC-005-GD and B3-09200B-FRCC-008-GD is 0.0080 (see Attachment 3).

In order to assess the dose contribution from the Circulating Water Discharge Tunnels, the concentration of each ROC in each judgmental measurement was also compared against the respective Base Case DCGLs. The calculation of the mean BcSOF for the Circulating Water Discharge Tunnels and the resultant dose is presented in Table 24.

Table 24 - Basic Statistical Properties of Judgmental ISOCS Measurements in Circulating Water Discharge Tunnel Mean Median Max Min BcDCGL Avg. SOF Avg. Dose ROC Std. Dev.

(pCi/m2) (pCi/m2) (pCi/m2) (pCi/m2) (pCi/m2) per ROC Per ROC Co-60 1.18E+06 1.43E+04 9.51E+06 8.73E+03 3.02E+06 7.03E+07 0.0168 0.4210 Cs-134 2.66E+04 1.86E+04 8.85E+04 1.08E+04 2.35E+04 1.59E+07 0.0017 0.0419 Cs-137 5.40E+04 1.91E+04 2.69E+05 1.42E+04 9.05E+04 2.11E+07 0.0026 0.0640 Ni-63 2.14E+08 2.58E+06 1.72E+09 1.58E+06 5.44E+08 2.18E+09 0.0980 2.4500 Sr-90 1.08E+02 3.82E+01 5.38E+02 2.84E+01 1.81E+02 7.74E+05 0.0001 0.0035 The mean BcSOF from random measurements taken on basement structural surfaces in Survey Unit B3-09200B is 0.1192. This is derived by summing the average SOF per ROC resulting from the average concentration in Table 24. The adjustment to the mean BcSOF from elevated measurements B3-09200B-FRFC-005-GD and B3-09200B-FRCC-008-GD is 0.0080. The adjusted mean BcSOF for Survey Unit B3-09200B is 0.1272, which equates to a dose of 3.180 mrem/yr.

A replicate measurement was acquired in the Circulating Water Discharge Tunnels at location B3-09200B-FQCC-009-GD. A summary of the results for the QC replicate measurement is provided in Table 25.

Table 25 - Summary of Replicate Measurement Taken in Circulating Water Discharge Tunnel for QC Co-60 Cs-134 Cs-137 Ni-63 Sr-90 MEASUREMENT ID OpSOF (pCi/m2) (pCi/m2) (pCi/m2) (pCi/m2) (pCi/m2)

B3-09200B-FQCC-009-GD 3.66E+02 7.06E+02 6.89E+02 6.60E+04 1.38E+00 0.0083 B3-09200B-FQCC-009-GD 1.04E+04 2.00E+04 1.95E+04 1.88E+06 3.90E+01 0.0078 Appendixes 1 through 13 present Release Records of FSS performed on ancillary areas and embedded pipe associated with the Turbine Building basement following the initial FSS

[41]

FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 performed in March of 2016. These areas were either not accessible or deferred at the time the Turbine Building basement was subjected to FSS. For example, the Unit 1 and Unit 2 Diesel Generator rooms on the 570 foot elevation are part of the surface area of the Turbine Building as specified in LTP Chapter 6, section 6.6.8.1. During decommissioning, both areas were used as the transit path for radioactive materials removed from the Auxiliary Building. This activity was active after the FSS performed in 2016 and was completed in 2018. Consequently, both Diesel Generator rooms were resurveyed for compliance as Class 1 areas. These Release Records are as follows; Appendix 10a S3-06105BF - Turbine Building 560 foot Embedded Floor Drain Pipe Appendix 10b B3-06107A - Unit 1 Tendon Buttress Pits Appendix 10c B3-06108A - Unit 2 Tendon Buttress Pits Appendix 10d B1-06201AF - Unit 1 Diesel Fuel Oil Storage Tank Room Appendix 10e B1-06202AF - Unit 2 Diesel Fuel Oil Storage Tank Room Appendix 10f S3-06209AF - Unit 1 Steam Tunnel Embedded Floor Drain Pipe Appendix 10g S3-06210AF - Unit 2 Steam Tunnel Embedded Floor Drain Pipe Appendix 10h S3-06211AF - Unit 1 Tendon Tunnel 547 foot Embedded Floor Drain Pipe Appendix 10i S3-06212AF - Unit 2 Tendon Tunnel 547 foot Embedded Floor Drain Pipe Appendix 10j B3-06213/14 - Unit 1 East and West Valve Houses Appendix 10k B3-06215/16 - Unit 2 East and West Valve Houses Each of the Appendixes listed above are stand-alone Release Records for the areas specified.

Table 26 below provides a summary of the FSS results from each. Specifics of the FSS performed in each are provided in each applicable Release Record.

The surface DCGL calculations for the Turbine Building accounted for the activity in the Circulating Water Intake Pipes and Circulating Water Discharge Tunnels by summing the surface areas of the connected structures and using the summed areas for the DCGL calculation. The results of the FSS of the Circulating Water Intake Pipes is presented in the Release Record for the Crib House/Forebay, however the Circulating Water Intake Pipes is also connected to the Turbine basement and therefore, the Intake Pipe surface area is also added to the Turbine Basement. The activity in the Circulating Water Intake Pipes is conservatively assumed to be in both basements simultaneously. The summary of the results of the FSS performed on the Circulating Water Intake Pipe (documented in the Release Record for the Crib House/Forebay) is also presented in Table 26.

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 Table 26 - Summary of Final Status Surveys Performed in Ancillary Areas and in Embedded Piping within the Turbine Building Basement of Mean Concentrations Area OpSOF Mean Dose Survey Unit Description Class Measure Co-60 Cs-134 Cs-137 Ni-63 Sr-90 BcSOF m2 ments (pCi/m2) (pCi/m2) (pCi/m2) (pCi/m2) (pCi/m2) Mean Max (mrem/yr)

S3-06105BF TB 560 ft Embedded Drains 237.5 3 133 9.69E+03 1.07E+02 7.96E+05 1.75E+06 1.59E+03 0.0114 1.17 0.0005 0.0114 B1-06201AF Unit1 570 ft DG Rooms 813 1 51 1.21E+04 2.94E+04 3.08E+04 2.18E+06 6.15E+01 0.0116 0.0385 0.0046 0.1140 B1-06202AF Unit 2 570 ft DG Rooms 813 1 51 1.51E+04 1.18E+04 2.89E+04 2.72E+06 5.78E+01 0.0430 0.2279 0.0037 0.0913 B1-06213 Unit 1 East Valve Room 304 1 26 1.48E+04 3.65E+04 7.01E+05 2.68E+06 1.40E+03 0.4569 4.2127 0.0758 1.8945 B1-06214 Unit 1 West Valve Room 304 1 26 1.61E+04 4.40E+04 3.20E+05 2.90E+06 6.40E+02 0.2617 1.8173 0.0326 0.8160 B3-06215 Unit 2 East Valve Room 240 3 20 1.91E+04 4.58E+04 6.91E+04 3.45E+06 1.38E+02 0.0965 0.3271 0.0082 0.2047 B3-06216 Unit 2 West Valve Room 240 3 20 1.77E+04 4.08E+04 9.95E+04 3.20E+06 1.99E+02 0.1091 0.3035 0.0093 0.2314 B3-06107A Unit 1 Tendon Buttress Pits 1596 3 7 4.95E+03 1.44E+03 6.95E+03 8.92E+05 1.39E+01 0.0108 0.0336 0.0009 0.0230 B3-06108A Unit 2 Tendon Buttress Pits 1596 3 6 2.47E+03 5.35E+03 5.32E+03 4.46E+05 1.06E+01 0.0099 0.0223 0.0008 0.0210 Unit 1 Tendon Tunnel 547 foot S3-06211AF 51 3 58 1.11E+04 1.21E+02 9.08E+05 2.00E+06 1.82E+03 0.0184 0.0739 0.0004 0.0092 Embedded Floor Drain Pipe Unit 2 Tendon Tunnel 547 foot S3-06212AF 42.1 3 44 8.23E+03 8.95E+01 6.74E+05 1.49E+06 1.35E+03 0.0136 0.0161 0.0003 0.0068 Embedded Floor Drain Pipe Unit 1 Steam Tunnel Embedded S3-06209AF 46.6 3 68 3.80E+04 4.13E+02 3.11E+06 6.86E+06 6.23E+03 0.0069 0.0178 0.0008 0.0199 Floor Drain Pipe Unit 2 Steam Tunnel Embedded S3-06210AF 46.1 3 60 1.19E+04 1.29E+02 9.73E+05 2.15E+06 1.95E+03 0.0022 0.0027 0.0003 0.0062 Floor Drain Pipe Unit 1 and Unit 2 Circulating B3-08102AS 440 3 4 8.99E+03 5.86E+02 7.86E+02 1.62E+06 1.57E+00 0.0002 0.0006 0.0001 0.0025 Water Intake Pipe

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 The activity in the Circulating Water Intake Pipes, Circulating Water Discharge Tunnels, Circulating Water Discharge Pipes, Buttress Pits/Tendon Tunnels, Diesel Generator Rooms and Valve Houses are included with Turbine Building through the DCGL calculation. The area-weighted mean of the measurements taken during FSS in these survey units will be added to the mean of the Turbine Building results. The entire surface areas will be included in the area-weighted average calculation.

The process for calculating the combined basement surface dose from each of the survey units and the calculation method is provided below. Table 27 lists the surface survey units that contribute to the Turbine Building basement.

Table 27 - Surface Survey Units Contributing to the Turbine Building Basement Surface Surface Surface Surface Surface Surface Surface Basement Survey Survey Survey Survey Survey Survey Survey Unit 1 Unit 2 Unit 3 Unit 4 Unit 5 Unit 6 Unit 7 Unit 1 and Unit 1 and Circulating Circulating Buttress Circulating Unit 2 Unit 2 All walls Water Water Pits/ Water Turbine Diesel Valve and floors Discharge Intake Pipe Tendon Discharge (1) Generator Houses Tunnel Tunnels(1) Pipe (1)

Rooms (1) Judgmental measurements only - Circulating Water Intake Pipe, Circulating Water Discharge Pipe and Buttress Pits/Tendon Tunnels are not survey units.

After passing the Sign test, the mean dose contribution for the multiple surface survey units in the Turbine Building basement were determined on an area-weighted basis. The total basement area used in the weighted average calculation is the adjusted surface area used to calculate the DCGLs in LTP Chapter 6, section 6.6.8. The adjusted areas used for the DCGL calculations for the Turbine Building, and applied in the weighted average calculation of total basement surface dose is 27,135 m2, which is reproduced from Chapter 6, section 6.6.8.1, Table 6-23.

The area-weighted SOF for Basements that have dose contributions from multiple surface survey units was calculated in accordance with Equation 5. For the Circulating Water Discharge Tunnels, Circulating Water Intake Pipe, Circulating Water Discharge Pipe and Buttress Pits/Tendon Tunnels, the SOFBi,B used in Equation 5 is the mean of the judgmental measurements that were taken.

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 Equation 5

, = ,

=1 where:

SOFB,B = total surface SOF including all surface survey units in basement (B)

SASUi,B = surface area of survey unit (i) in basement (B)

SAAdjust,B = adjusted surface area for DCGL calculation (LTP Chapter 5, Table 5-23) for basement (B)

SOFBi,B = SOFB for survey unit (i) in basement (B)

8. QUALITY CONTROL In compliance with ZS-LT-01, replicate measurements were performed on 5% of the survey locations chosen at random. Two (2) replicate measurements were taken, one in the Turbine Building basement and one in the Circulating Water Tunnel. Using the acceptance criteria specified ZS-LT-01, Quality Assurance Project Plan (QAPP) for Characterization and Final Status Survey, there was acceptable agreement between the replicate and original readings.

Refer to Attachment 5 for quality control analysis results.

9. INVESTIGATIONS AND RESULTS When FSS of the Turbine Building was performed in March of 2016, it was performed at risk in accordance with the initial version of the LTP, which was not approved. The initial analysis of the Turbine Building and Circulating Water Discharge Tunnel FSS data was directly compared against the BILs from the draft LTP to determine the SOF of individual measurements. When compared against the BILs, all measurements taken for the FSS of these three survey units were less than a SOF of 0.5. Consequently, no investigations were required or performed at the time the survey was performed. However, when the measurement results were compared against the Operational DCGLs from the approved revision 2 of the LTP, several measurements exceeded a SOF of 0.5 and several measurements exceeded a SOF of one. In accordance with LTP Chapter 5, section 5.6.4.6, as these survey units were classified as Class 3, an investigation should have been performed and an assessment made to determine if reclassification was warranted. This was not accomplished. By the time this discrepancy was identified, the Turbine Building basement void had been completely backfilled and additional investigations were not possible. It should be noted that with the exception of the two measurements taken under the Unit 2 Down-comer in the Unit 2 Discharge Tunnel, all measurements were less that a SOF of 0.5 when compared against the Base Case DCGLs. The BcSOF for the two measurements in the Unit 2 Discharge Tunnel were less than one.

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100

10. REMEDIATION AND RESULTS Historically, no radiological remedial action as described by MARSSIM Section 5.4 was performed in this survey unit prior to or as a result of the FSS. Chapter 4 of the ZSRP LTP determined that remediation beyond that required to meet the release criteria is unnecessary and that the remaining residual radioactivity was ALARA.

11. CHANGES FROM THE SURVEY PLAN There were no addendums to the FSS plan.

12. DATA QUALITY ASSESSMENT (DQA)

In accordance with procedure ZS-LT-300-001-004, Final Status Survey Data Assessment (Reference 14), the DQOs, sample design, and data were reviewed for completeness, accuracy, and consistency. Documentation was complete and legible. The FSS unit was properly classified as Class 3. All measurement results were individually reviewed and validated. The number of measurements was sufficient to meet the areal coverage requirements for accessible surfaces. The instrumentation used to perform the FSS were in calibration, capable of detecting the activity with an adequate MDC and successfully response checked prior to and following use. An adequate number of replicate measurements were taken and the results meet the acceptance criteria as specified in the QAPP.

The Sign Test (Attachment 4) was performed on the data and compared to the original assumptions of the DQOs. The evaluation of the Sign Test results clearly demonstrates that the survey unit passes the unrestricted release criteria, thus, the null hypothesis is rejected.

The preliminary data review consisted of calculating basic statistical quantities (e.g., mean, median, standard deviation). All data was considered valid including negative values, zeros, values reported below the MDC, and values with uncertainties greater than two standard deviations. The mean and median values for each ROC were well below the respective Operational DCGLs. Also, the retrospective power curve shows that a sufficient number of samples were collected to achieve the desired power. Therefore, the survey unit meets the unrestricted release criteria with adequate power as required by the DQOs.

The data for Co-60 and Cs-137 is represented graphically through a frequency plot and a quantile plot. All graphical representations are provided in Attachment 6.

13. ANOMALIES No anomalies were observed during the performance or analyses of the survey.

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100

14. COMPLIANCE EQUATION There are four distinct source terms for the end-state at Zion: backfilled basements, soil, buried piping and groundwater. Demonstrating compliance with the dose criterion requires the summation of dose from the four source terms (see Equation 6-11 from LTP Chapter 6, section 6-17).

The final compliance dose will be calculated using Equation 6-11 after FSS has been completed in all survey units. The results of the FSS performed for each FSS unit will be reviewed to determine the maximum dose from each of the four source terms (e.g., basement, soil, buried pipe and existing groundwater if applicable) using the mean Base Case SOF of FSS results plus the dose from any identified elevated areas. The compliance dose must be less than 25 mrem/yr. The dose contribution from each ROC is accounted for using the Base Case SOF (BcSOF) to ensure that the total dose from all ROC does not exceed the dose criterion.

The term for each Basement includes the dose contributions from wall and floor surfaces within the Basement, the dose contribution from embedded pipe within the Basement, the dose contribution from penetrations within the Basement and the dose contribution from concrete fill in the Basement when clean concrete debris was used as fill. Each (structural surfaces, embedded pipe and penetrations) are surveyed separately during FSS. The dose from clean concrete fill is predetermined in accordance with LTP Chapter 5, Table 5-16, which is conservatively based on a maximum allowable MDC of 5,000 dpm/100cm2. The dose from fill assigned to the Turbine Building basement is 1.58 mrem/yr, which equates to a SOF of 0.0632.

Basement surface area adjustments (i.e. increases) were applied to the structure surface DCGL calculation for certain basements to ensure that the DCGLs accounted for the contribution of residual radioactivity from basements/structures that cannot, on their own, support a water supply well but were hydraulically connected to a basement that could support a well. One of these structures is the Circulating Water Intake Pipes. The surface area adjustments resulted in lowering the DCGL concentrations (pCi/m2) in the Crib House/Forebay by requiring the allowable total activity to be uniformly distributed over the larger, combined surface areas.

The activity in the Circulating Water Intake Pipes is included in both the Crib House/Forebay and the Turbine Basement. The Intake Pipe was grouted which essentially eliminated the hydraulic connections however, in calculating the Base Case DCGLs, the hydraulic connections to the Intake Pipe was assumed to be fully regained in the future after degradation of the isolation barriers and grout.

The Base Case DCGLs for the Turbine Building account for the activity in the Circulating Water Intake Pipes, Circulating Water Discharge Tunnels, Circulating Water Discharge Pipes, Buttress Pits/Tendon Tunnels, Diesel Generator Rooms and Valve Houses by summing the surface areas. In accordance with LTP Chapter 6, Table 6-23, the combined summed surface area of the Turbine Building is 27,135 m2. The areas for each of the surface areas within the

[47]

FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 Turbine Building are provided in Table 26. Area weighting using Equation 5 was used to sum for the residual activity in the Circulating Water Intake Pipes, Circulating Water Discharge Tunnels, Circulating Water Discharge Pipes, Buttress Pits/Tendon Tunnels, Diesel Generator Rooms and Valve Houses on an area-weighted basis. The result is provided in Equation 6.

Equation 6 4868 304 304 1075 813 (0.1272) + (0.0758) + (0.0326) + (0.0124) + (0.0046) +

27135 27135 27135 27135 27135 813 240 240 1596 1596 (0.0037) + (0.0082) + (0.0093) + (0.0009) + (0.0008) +

27135 27135 27135 27135 27135 440 (0.0001) = 0.0250 27135 The SOF of 0.0250 is added to the mean BcSOF for the Turbine Building to derive the adjusted BcSOF of 0.0459 for the Turbine Building basement structure. This equates to a dose of 1.1470 mrem/yr. The adjusted BcSOF for the Turbine Building is then used in the following equation to calculate BcSOFBASEMENT for the Turbine Building.

Equation 7

= + + +

where:

BcSOFBASEMENT = BcSOF (mean of FSS systematic results plus the dose from any identified elevated areas) for backfilled Basements BcSOFB = BcSOF for structural survey unit(s) within the Basement (mean of FSS systematic results plus the dose from any identified elevated areas)

BcSOFEP = BcSOF for embedded pipe survey unit(s) within the Basement (mean of FSS systematic results plus the dose from any identified elevated areas)

BcSOFPN = BcSOF for penetration survey unit(s) within the Basement (mean of FSS systematic results plus the dose from any identified elevated areas)

BcSOFCF = BcSOF for clean concrete fill (if applicable) based on maximum MDC during Unrestricted Release Survey (URS)

In accordance with TSD 14-016, there were 11 penetrations (T91, T92, T93, T94, T96, T97, T98, T99, T100, T101 and T104) that accessed the exterior C wall of the Turbine Building basement (east wall) between 585 foot and the 586 foot elevation. All the penetrations on the East Wall of the Turbine Building were concentrated in and around the basement Oil Room at

[48]

FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 the centerline of the building. As all the penetrations in question were shallow in relation to the final end-state grade (588 foot elevation), the pipes were all removed during decommissioning and the openings in the wall were grouted. Penetrations also interfaced between the Turbine Building and the Auxiliary Building, primarily through the G wall but also through the north and south walls into the Unit 1 and Unit 2 Steam Tunnels, as well as both Unit 1 and Unit 2 Containments, through the Unit 1 and Unit 2 Main Steam Valve Houses. LTP Chapter 6, section 6.4.5 states, The dose from penetrations is summed with the dose from the wall and floor surfaces of both basements that the penetration interface. The dose fraction for the Turbine Building penetrations that interface with the Auxiliary Building was 0.0023 and, the dose fraction for the Turbine Building penetrations that interface with the Unit 1 and Unit 2 Containments are 0.0002 and 0.0002 respectively. The resultant dose fractions were summed for a value of 0.0027, which equates to the BcSOFPN variable for the Turbine Building.

The value for embedded pipe in the Turbine Building is a summation of the BcSOF for the 560 foot elevation floor drains, the Unit 1 and Unit 2 Steam Tunnel floor drains and the Unit 1 and Unit 2 Tendon Tunnel floor drains. These values are listed in Table 26 and sum for a BcSOF value of 0.0023.

The BcSOFBASEMENT value for the Turbine Building is then derived as follows; Equation 8

= 0.0459 + 0.0023 + 0.0027 + 0.0632 = 0.1141 The BcSOFBASEMENT for the Turbine Building basement is 0.1141. This SOF equates to a dose of 2.8525 mrem/yr TEDE to an AMCG from residual radioactivity in the Turbine Building basement.

15. CONCLUSION Survey Unit B3-06100, Turbine Building Basement, Survey Unit B3-09200B, Circulating Water Discharge Tunnels and Survey Unit S3-06105AS, Unit 1 and Unit 2 Circulating Water Discharge Pipe have met the DQOs of their respective FSS plans. The ALARA criteria as specified in Chapter 4 of the LTP were achieved. The EMC is not applicable to structural surfaces and remediation was not required.

All identified ROC were used for statistical testing to determine the adequacy of the survey unit for FSS. Evaluation of the data shows that none of the mean ROC concentration values exceeds the Operational DCGL; therefore, in accordance with the LTP Section 5.10, the survey unit meets the release criterion.

The sample data passed the Sign Test. The null hypothesis was rejected. The Retrospective Power Curve showed that adequate power was achieved. The survey units were properly classified.

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 The dose contribution from structural surfaces in Survey Unit B3-06100, Turbine Building Basement, is 1.1475 mrem/year TEDE, based on the average concentration of the ROC in samples used for non-parametric statistical sampling as well as measurements taken in the Circulating Water Intake Pipes, Circulating Water Discharge Tunnels, Circulating Water Discharge Pipes, Buttress Pits/Tendon Tunnels, Diesel Generator Rooms and Valve Houses on an area-weighted basis. The dose from penetrations in the Turbine Building is 0.0675 mrem/yr TEDE, the dose from embedded pipe in the Turbine Building is 0.0575 mrem/year TEDE and the dose from clean fill is 1.5800 mrem/yr. The total dose attributed to the Turbine Building as a summation of all dose components is 2.8525 mrem/yr.

Survey Unit B3-06100, Turbine Building Basement is acceptable for unrestricted release.

16. REFERENCES

1. ZionSolutions ZS-LT-300-001-005, Final Status Survey Data Reporting

2. Zion Station Restoration Project License Termination Plan (LTP), Revision 2

3. ZionSolutions ZS-LT-300-001-001, Final Status Survey Package Development

4. NUREG-1575, Revision 1, Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM)

5. ZionSolutions TSD 14-016, Description of Embedded Piping, Penetrations, and Buried Pipe to Remain in Zion End State

6. ZionSolutions procedure ZS-LT-300-001-002, Survey Unit Classification

7. Zion Station Historical Site Assessment (HSA)

8. ZionSolutions TSD 11-001, Potential Radionuclides of Concern during the Decommissioning of Zion Station

9. ZionSolutions TSD 14-019, Radionuclides of Concern for Soil and Basement Fill Model Source Terms

10. ZionSolutions TSD 17-004, Operational Derived Concentration Guideline Levels for Final Status Survey

11. ZionSolutions procedure ZS-LT-01, Quality Assurance Project Plan (QAPP) for Characterization and Final Status Survey

12. ZionSolutions procedure ZS-LT-300-001-003, Isolation and Control for Final Status Survey

13. ZionSolutions TSD 14-022, Use of In-Situ Gamma Spectroscopy for Source Term Survey of End State Structures

14. ZS-LT-300-001-004, Final Status Survey Data Assessment

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100

17. ATTACHMENTS

1. Attachment 1 - Maps

2. Attachment 2 - Graphical Presentations

3. Attachment 3 - Sign Test

4. Attachment 4 - QC Measurement Assessment

5. Attachment 5 - ISOCS Geometry

6. Attachment 6 - ISOCS Reports

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 ATTACHMENT 1 - MAPS

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 FIGURE 1

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 FIGURE 2

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 FIGURE 3

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 FIGURE 4

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 ATTACHMENT 2 - GRAPHICAL PRESENTATIONS

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 QUANTILE PLOT FOR Co-60 Survey Unit: 6100 Survey Unit Name: Turbine Building Basement Mean: 7.45E+04 pCi/g Quantile Plot For Co-60 200000 180000 160000 Concentration (pCi/g) 140000 120000 100000 80000 60000 40000 20000 0

0 0.2 0.4 0.6 0.8 1 Percentage

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 QUANTILE PLOT FOR Cs-137 Survey Unit: 6100 Survey Unit Name: Turbine Building Basement Mean: 1.56E+05 pCi/g Quantile Plot For Cs-137 1.80E+06 1.60E+06 1.40E+06 Concentration (pCi/g) 1.20E+06 1.00E+06 8.00E+05 6.00E+05 4.00E+05 2.00E+05 0.00E+00 0% 20% 40% 60% 80% 100%

Percentage

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 HISTOGRAM FOR Co-60 Survey Unit: 6100 Survey Unit Name: Turbine Building Basement Mean: 7.45E+04 pCi/g Median: 1.45E+04 pCi/g ST DEV: 6.89E+04 Skew: 0.206706954 Upper Value Observation Frequency Observation %

1.48E+04 15 100%

1.66E+04 0 0%

1.84E+04 0 0%

2.02E+04 0 0%

2.19E+04 0 0%

2.37E+04 0 0%

2.55E+04 0 0%

2.55E+04 0 0%

TOTAL 15 Frequency Plot For Co-60 20 15 Frequency 10 5

0 1.48E+041.66E+041.84E+042.02E+042.19E+042.37E+042.55E+042.55E+04 Upper End Value (pCi/g)

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 HISTOGRAM FOR Cs-137 Survey Unit: 6100 Survey Unit Name: Turbine Building Basement Mean: 1.56E+05 pCi/g Median: 2.19E+04 pCi/g ST DEV: 314938.4205 Skew: 4.557864398 Upper Value Observation Frequency Observation %

1.85E+04 8 53%

2.12E+04 6 40%

2.38E+04 1 7%

2.64E+04 1 7%

2.90E+04 -1 -7%

3.17E+04 0 0%

3.43E+04 0 0%

3.69E+04 0 0%

TOTAL: 15 Frequency Plot For Cs-137 10 8

Frequency 6

4 2

0 1.85E+04 2.12E+04 2.38E+04 2.64E+04 2.90E+04 3.17E+04 Upper End Value (pCi/g)

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 ATTACHMENT 3 - SIGN TEST

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 Turbine Building BASEMENT FSS Survey Area 06000 Description unit Survey Turbine Building Surfaces (Walls &

06100A&B Description Unit Floors) & Steam Tunnels Number of Classification 1 Type I Error 0.05 28 Measurements SOF 1-Ws Sign (Ws) 1 0.0361 0.96 +1 2 0.0405 0.96 +1 3 0.0127 0.99 +1 4 0.0398 0.96 +1 5 0.0408 0.96 +1 6 0.0370 0.96 +1 7 0.0353 0.96 +1 8 0.0190 0.98 +1 9 0.0367 0.96 +1 10 0.0387 0.96 +1 11 0.0407 0.96 +1 12 0.0420 0.96 +1 13 0.0417 0.96 +1 14 0.0356 0.96 +1 15 0.4445 0.56 +1 16 1.3460 (0.35) -1 17 0.4295 0.57 +1 18 0.4754 0.52 +1 19 0.4336 0.57 +1 20 0.2695 0.73 +1 21 0.4512 0.55 +1 22 0.3783 0.62 +1 23 0.3998 0.60 +1 24 0.3963 0.60 +1 25 0.4711 0.53 +1 26 0.4179 0.58 +1 27 0.4201 0.58 +1 28 0.0432 0.96 +1

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 Number of positive 27 differences (S+)

Critical Value 18 Survey Unit Meets the Acceptance Criteria

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 ATTACHMENT 4 - QC MEASUREMENT ASSESSMENT

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 Duplicate Sample Assessment Form Survey Area #: 06100 Survey Unit # 06100A Survey Unit Name: Turbine Building Basement 560' elevation Floor and Walls Sample Plan#: B3-06100A-S Sample

Description:

Comparison of systematic and QC ISOCS measurements of concrete wall at GRID #9. The standard measurement is ID as B3-06100A-FRWC-009-GD. The comparison measurement is ID as B3-06100A-FQWC-009-GD STANDARD COMPARISON Activity Activity Standard Agreement Standard Comparison Acceptable Radionuclide Value Resolution Value Error Range Error Ratio (Y/N)

(pCi/m2) (pCi/m2)

K-40 7.88E+05 1.72E+05 5 0.5-2.0 8.44E+05 1.82E+05 0.9 Y Comments/Corrective Actions: None Table is provided to show acceptance criteria used to assess split samples.

Performed by: Patsy Giza Date: Reveiwed by: Date:

1/21/2019 1/21/2019

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 Duplicate Sample Assessment Form Survey Area #: 06100 Survey Unit # 06100B Survey Unit Name: Turbine Building Basement 560' elevation Steam Tunnel Sample Plan#: B3-06100B-S Sample

Description:

Comparison of systematic and QC ISOCS measurements of concrete wall at GRID #11. The standard measurement is ID as B3-06100B-FRWC-011-GD. The comparison measurement is ID as B3-06100B-FQWC-011-GD STANDARD COMPARISON Activity Activity Standard Agreement Standard Comparison Acceptable Radionuclide Value Resolution Value Error Range Error Ratio (Y/N)

(pCi/m2) (pCi/m2)

K-40 1.81E+07 2.58E+06 7 0.5-2.0 1.80E+07 2.64E+06 1.0 Y Comments/Corrective Actions: None Table is provided to show acceptance criteria used to assess split samples.

Performed by: Patsy Giza Date: Reveiwed by: Date:

1/21/2019 1/21/2019

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 1/21/2019

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 1/21/2019

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 Duplicate Sample Assessment Form Survey Area #: 08102B Survey Unit # 08102 Survey Unit Name: Unit 1 Circ Water Intake Pipes Sample Plan#: B3-08102B Sample

Description:

Comparison of systematic and QC ISOCS measurements of concrete wall at GRID #2. The standard measurement is ID as B1-08102B-SFJSM-002-GD. The comparison measurement is ID as B1-08102B-SQFC-002-GD STANDARD COMPARISON Activity Activity Standard Agreement Standard Comparison Acceptable Radionuclide Value Resolution Value Error Range Error Ratio (Y/N)

(pCi/m2) (pCi/m2)

K-40 1.48E+05 8.76E+04 2 0.4-2.5 2.07E+05 1.00E+05 0.7 Y Co-60 1.18E+05 1.85E+04 6 0.5-2.0 1.11E+05 1.77E+04 1.1 Y Comments/Corrective Actions: None Table is provided to show acceptance criteria used to assess split samples.

Performed by: Patsy Giza Date: Reveiwed by: Date:

1/21/2019

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 ATTACHMENT 5 - ISOCS GEOMETRY

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100

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FSS RELEASE RECORD TURBINE BUILDING SURVEY UNIT 06100 ATTACHMENT 6 - ISOCS REPORTS

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