Text

Final Status Survey (FSS) Final Report - Phase 2, Part 1, Crib House/Forebay Basement Survey Unit 08100
	ML19077A065
Person / Time
Site:	Zion File:ZionSolutions icon.png
Issue date:	11/27/2018
From:	-Neednewvalue; ZionSolutions
To:	; Office of Nuclear Material Safety and Safeguards
References
	ZS-2019-0017
	Download: ML19077A065 (214)
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ZION STATION RESTORATION PROJECT FINAL STATUS SURVEY RELEASE RECORD CRIB HOUSE/FOREBAY BASEMENT SURVEY UNIT 08100

FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 PREPARED BY / DATE: ____ 11/27/2018________

Daniel R. Mihalik, Radiological Engineer 11/27/2018 REVIEWED BY / DATE: _________________________________________

G. L. Wood, Radiological Engineer 11/27/2018 APPROVED BY / DATE: _________________________________________

D. Wojtkowiak, C/LT Manager

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 TABLE OF CONTENTS

1. EXECUTIVE

SUMMARY

..................................................................................................... 7

2. SURVEY UNIT DESCRIPTION ........................................................................................... 8

3. CLASSIFICATION BASIS .................................................................................................. 11

4. DATA QUALITY OBJECTIVES (DQO) ........................................................................... 13

5. SURVEY DESIGN ................................................................................................................ 17

6. SURVEY IMPLEMENTATION.......................................................................................... 26

7. SURVEY RESULTS.............................................................................................................. 28

8. QUALITY CONTROL ......................................................................................................... 34

9. INVESTIGATIONS AND RESULTS ................................................................................. 35

10. REMEDIATION AND RESULTS ................................................................................... 35

11. CHANGES FROM THE FINAL STATUS SURVEY PLAN ........................................ 35

12. DATA QUALITY ASSESSMENT (DQA) ...................................................................... 35

13. ANOMALIES ..................................................................................................................... 36

14. COMPLIANCE EQUATION ........................................................................................... 36

15. CONCLUSION .................................................................................................................. 38

16. REFERENCES ................................................................................................................... 39

17. ATTACHMENTS .............................................................................................................. 40 ATTACHMENT 1 .............................................................................................................. 41 ATTACHMENT 2 .............................................................................................................. 59 ATTACHMENT 3 .............................................................................................................. 66 ATTACHMENT 4 ............................................................................................................ 201 ATTACHMENT 5 ............................................................................................................ 203 ATTACHMENT 6 ............................................................................................................ 205 ATTACHMENT 7 ............................................................................................................ 209

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 LIST OF TABLES Table 1 - Statistical Quantities for Cs-137 and Co-60 from the 2012 Characterization Survey .... 12 Table 2 - Dose Significant Radionuclides and Mixture .................................................................. 15 Table 3 - Base Case DCGLs for Crib House/Forebay Basement Survey Unit (BcDCGLB) .......... 16 Table 4 - Operational DCGLs for Crib House/Forebay Basement Survey Unit (OpDCGLB) ....... 17 Table 5 - Surrogate Ratios .............................................................................................................. 18 Table 6 - Action Levels for Survey Unit B3-08100A..................................................................... 19 Table 7 - Adjusted Minimum Number of ISOCS Measurements................................................... 20 Table 8 - Random ISOCS Measurement Locations ........................................................................ 21 Table 9 - Circulating Water Intake Pipe Judgmental Sample Measurement Locations ................. 22 Table 10 - Forebay Judgmental Sample Measurement Locations .................................................. 23 Table 11 - Investigation Levels....................................................................................................... 25 Table 12 - Synopsis of Survey Design ............................................................................................ 25 Table 13 - Summary of Gamma Spectroscopy Results for ISOCS Measurements Comprising the Statistical Sample Population.............................................................. 29 Table 14 - Basic Statistical Properties of Random ISOCS Measurements ..................................... 29 Table 15 - Summary of ISOCS Replicate Measurement for QC .................................................... 30 Table 16 - Summary of Gamma Spectroscopy Results for Judgmental ISOCS Measurements Taken in Circulating Water Intake Pipes ...................................................................... 30 Table 17 - Summary of ISOCS Replicate Measurement for QC .................................................... 30 Table 18 - Summary of Results for Judgmental Measurements Taken in the Forebay .................. 31 Table 19 - Summary of Replicate Measurement Taken in Forebay for QC ................................... 31 Table 20 - Sum-of-Fractions for Random ISOCS Measurements .................................................. 32 Table 21 - Sum-of-Fractions for Judgmental ISOCS Measurements Taken in the Circulating Water Intake Pipe....................................................................................... 33 Table 22 - Sum-of-Fractions for Judgmental Gamma Measurements Taken in the Forebay......... 33 Table 23 - Calculation of Mean Sum-of-Fractions for Judgmental Measurements Taken in the Circulating Water Intake Pipe Using Base Case DCGLs ................................... 34 Table 24 - Calculation of Mean Sum-of-Fractions for Judgmental Measurements Taken in the Forebay Using Base Case DCGLs ...................................................................... 34

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 LIST OF ACRONYMS AND ABBREVIATIONS ALARA As Low As Reasonably Achievable AMCG Average Member of the Critical Group BFM Basement Fill Model CoC Chain-of-Custody DQA Data Quality Assessment DQO Data Quality Objective DCGL Derived Concentration Guideline Level EMC Elevated Measurement Comparison FSS Final Status Survey GPS Global Positioning System HTD Hard-to-Detect IC Insignificant Contributor LTP License Termination Plan LBGR Lower Bound of the Gray Region MARSSIM Multi-Agency Radiation Survey and Site Investigation Manual MDC Minimum Detectable Concentration MDCR Minimal Detectable Count Rate NAD North American Datum NaI Sodium Iodide OpDCGL Operational Derived Concentration Guideline Level QAPP Quality Assurance Project Plan QC Quality Control RE Radiological Engineer ROC Radionuclides of Concern SOF Sum-of-Fraction TEDE Total Effective Dose Equivalent

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 UBGR Upper Bound of the Gray Region UCL Upper Confidence Level USNRC United States Nuclear Regulatory Commission VCC Vertical Concrete Cask VSP Visual Sample Plan ZNPS Zion Nuclear Power Station ZSRP Zion Station Restoration Project

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100

1. EXECUTIVE

SUMMARY

This Final Status Survey (FSS) Release Record for Survey Unit #B3-08100A, Crib House/Forebay basement survey unit, has been generated for the Zion Station Restoration Project (ZSRP) 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 #B3-08100A, Crib House/Forebay includes FSS design and FSS results for the following;

B3-08101A Crib House/Forebay Structural Surfaces

B3-08102AS Unit 1 Circulating Water Intake Pipe

B3-08102BS Unit 2 Circulating Water Intake Pipe

B3-08401AF Forebay Submerged Surfaces 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).

In accordance with ZSRP LTP Chapter 5, section 5.5.2.1.2 and Table 5-19, the Crib House/Forebay basement survey unit has a MARSSIM classification of 3. A survey plan was 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 Crib House/Forebay basement survey unit. As a random sample population, fourteen (14) randomly located static ISOCS measurement locations were designated on accessible structural surfaces within the survey unit. The surface area of the Forebay was deemed as not accessible at the time of FSS as it was flooded and hydraulically connected to Lake Michigan. Based on a measurement Field-of-View (FOV) of 28 m2 for each random ISOCS measurement, the areal scan surface coverage for the measurements equated to 392 m2, or approximately 3% of the total surface area of the Crib House/Forebay basement survey unit (18,254 m2). In addition, two (2) judgmental ISOCS measurements were taken inside each of the Unit 1 and Unit 2 Circulating Water Intake Pipes, each with a FOV of 78 m2 per measurement, or an additional 312 m2 of areal scan surface coverage.

The Forebay surface area that was, and continues to be submerged, equated to a surface area of 5,407 m2, or 30% of the total surface area of the Crib House/Forebay basement survey unit. ZionSolutions TSD 17-006, Underwater Survey Methodology for Zion

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 Nuclear Station Crib House/Forebay Basement Final Status Survey Unit (Reference 5) was developed for the use of scintillation detectors in dry tubes to acquire radiological data of the submerged wall surfaces for FSS. Fourteen (14) judgmental measurements were taken at biased locations within the Forebay using this survey approach.

The results for all ISOCS and gross gamma measurements (random and judgmental) taken in the Crib House/Forebay basement survey unit indicate that the Sum-of-Fraction (SOF) for each measurement, considering the concentration of all applicable Radionuclides of Concern (ROC), either by direct measurement or by inference, is less than 0.1 when applying the respective Operational Derived Concentration Guideline Levels (OpDCGL) for the Crib House/Forebay from ZionSolutions TSD 17-004, Operational Derived Concentration Guideline Levels for FSS (Reference 6). Therefore the null hypothesis is rejected and the Crib House/Forebay basement survey unit is acceptable for unrestricted release.

2. SURVEY UNIT DESCRIPTION The Crib House/Forebay 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 Crib House/Forebay basement structure is located within Class 1 open land survey units

L112204A, #L112204B and #L112204C.

PICTURE 1 CRIB HOUSE 559 FT ELEVATION

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 The 552 ft. and 559 ft. elevation of the Crib House contained the upper pump housings of the six circulatory pumps, three for Unit 1 and three for Unit 2 that provide cooling water from Lake Michigan to various heat exchangers and condensers in the Turbine Building and Auxiliary Building. In addition, the intake/outtake plenum under the Crib House contained the cooling water outlet from these systems back into the lake. The 552 ft.

elevation also contained the Crib House sumps and sump system components which served as the collection point for the Crib House drain piping.

Prior to demolition, the Crib House was comprised of two elevations, the 594 ft. elevation, which was constructed using cinderblock walls and the 559 ft. elevation, which was constructed of concrete walls and floors. The basement 559 ft. elevation consisted of a room measuring 171 feet long by 37.5 feet wide, resulting in a floor surface area of 6,412.5 ft2 or 595.74 m2. The basement was accessed by two stairways, one to the north and one to the south from the Crib House 594 ft. elevation. The room could also be accessed by a hoist-well from the 594 ft. elevation that was located between Circulation Pumps 1A and 2A. The west portion of the basement was sunken to a depth of 552 ft.

elevation, which housed the sumps and sump pump system valves. The remainder of the 559 ft. elevation was mostly unencumbered with the exception of the pump housings from each of the circulation pumps protruding from the floor.

PICTURE 2 CRIB HOUSE ENGINEERING PRINT The engineering drawings of the 559 ft. and 552 ft. elevation indicated that the concrete walls were 4 feet thick and the floor was 2 ft., 6 inches think. The concrete and floor was covered with a grey paint. Standing water, to a depth of approximately 1/4 inch surrounded

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 several of the sumps on the 552 ft. elevation. In addition, the floor paint at several locations was discolored indicating frequent contact with water. The 559 ft. elevation was dry and relatively free of discoloration. Several cat-walks and system piping were suspended from the ceiling of the room. All utilities, including electrical and drain systems were external from the concrete structure and were not embedded.

The Forebay structure was built to house and protect offshore water intakes providing cooling water from Lake Michigan to the Circulating Water Pumps, which in turn supplied various heat exchangers and condensers in the Turbine Building. It consisted of poured concrete walls, plate steel reinforcements and steel flow restriction gates along with associated conduits, piping and mechanical actuators. These walls and components began at approximately 596 ft. elevation and extended to approximately 537 ft. elevation with a mean Lake Michigan level of 577 ft. elevation.

PICTURE 3 FOREBAY The Circulating Water Pumps took suction on the Forebay and pumped cooling water into the Circulating Water Intake Pipes. The Circulating Water Intake Pipes entered the east side of the Turbine Building, beneath the Condenser Water Boxes. The interior surface area of the Circulating Water Intake piping was 4,412 m2, but the only portions that were accessible were the two vertical lengths of 9 diameter piping (in each unit) from the 588 ft. elevation to the 558 ft. elevation (approximate surface area of 158 m2).

The Circulating Water Intake Pipes are also located within Class I open land Survey Units

L1-12205A, #L1-12205B, #L1-12205C, #L1-12205D and #L1-12205E. The boundaries of the Crib House basement footprint were defined using a Global Positioning System

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 (GPS) based on the Illinois State Plane System North American Datum of 1927 (NAD27).

The reference coordinates associated with this survey unit are denoted on Figure 1 located in Attachment 1.

3. CLASSIFICATION BASIS The Crib House/Forebay Survey Unit #B3-08100A was initially classified in the Zion Station Historical Site Assessment (HSA) (Reference 7). The interior 552 ft. and 559 ft.

elevation concrete surfaces in the basement structure survey unit were originally designated as non-impacted. The Crib House/Forebay survey unit was not located in a radiologically controlled area. In addition, no radiological postings or labeled radioactive material were identified in or around the Crib House/Forebay structure and an RWP was not required for entry. The HSA classified the exterior of the building as well as the grounds surrounding the building as MARSSIM Class 2. The HSA classified the Circulating Water Intake Pipe interior surfaces as Class 3.

Fixed residual radioactive material was discovered on the 594 ft. elevation of the Crib House in 1985. In addition, the Circulatory Water system was the normal effluent release pathway for the facility during operation. Based upon use, location and previous findings, the MARSSIM classification for the interior of the Crib House was changed from its original classification of non-impacted to a MARSSIM impacted Class 2 classification in accordance with ZionSolutions procedure ZS-LT-300-001-002, Survey Unit Classification (Reference 8).

As part of Site Characterization, ZionSolutions acquired and analyzed twenty (20) concrete core samples taken from the 559 ft. elevation of the Crib House in March and April of 2012. Sixteen (16) 6-inch concrete core samples were taken from the floors and four (4) 6-inch concrete core samples were taken from the lower walls. Sample locations were selected at random. Prior to acquiring the core samples, the area was scanned to ensure the absence of surface radioactive contamination at each sample location. Scans were performed with a Ludlum 43-93 100cm2 alpha-beta scintillation detector. Gross beta background ranged from 150 cpm to 300 cpm. No activity greater than background was observed by scan. All concrete core samples were analyzed by the on-site gamma spectroscopy system for gamma emitting radionuclides. Only natural activity expected in background was detected during the analysis. No other licensed materials were identified in the samples.

The locations of scan areas and concrete core samples taken during the characterization of the interior surfaces of the Crib House are illustrated on Figure 2 in Attachment 1. A summary of the analyses results for the concrete core samples taken during site characterization are presented in Table 1.

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 Table 1 - Statistical Quantities for Cs-137 and Co-60 from the 2012 Characterization Survey Cs-137 Co-60 Statistical Quantities (pCi/g) (pCi/g)

Maximum Value : 9.24E-02 1.44E-01 Mean : 7.00E-02 1.20-01 Standard Deviation : 1.07E-02 1.84E-02 On November 17 and 18, 2014, six (6) samples were taken of sediment from the Forebay and Crib House basement while divers were used to install cofferdams and plugs.

Analysis of the samples indicated the presence of Cs-137 at concentrations ranging from less than Minimum Detectable Concentration (MDC) to 1.09E-01 pCi/g. No other plant-derived radionuclides were detected.

The Crib House above the 588 foot elevation was surveyed for unconditional release in January and February of 2015. Once it was demonstrated that the Crib House internal surfaces were suitable for unconditional release, a demolition contractor salvaged clean equipment out of the Crib House. Unrestricted release surveys were performed in March of 2015 on equipment removed prior to and during the demolition of the upper levels of the Crib House, including the Circulating Water pumps 1A and 1B, Butterfly Disk 1C, Turning Vanes, Rotating Assembly and the interior of the Circ. Water Intake Pipes from the 552ft elevation of the Crib House. All smear and direct readings were less than MDC.

The Crib House structural concrete and cinder block above the 588 ft. elevation was also surveyed to demonstrate that the material was free of plant-derived radionuclides at concentrations greater than background. The concrete and cinderblock Crib House structure above the 588 ft. elevation was demolished and stockpiled to be used as clean hard fill.

In accordance with the Basement Fill Model (BFM), the classification for this survey unit was changed from its original classification 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 are therefore not applicable. At the time of LTP submittal, the Forebay and the Circulating Water Intake Piping were completely underwater and not accessible.

Process knowledge and the results of environmental monitoring of radiological conditions at effluent outfalls in the past indicate that the probability of residual radioactivity in these FSS units exceeding 50% of the Operational DCGLB for the Crib House/Forebay is very low.

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 The FSS unit for the basement of the Crib House/Forebay and the Circulating Water Intake Pipe was designated as Class 3 as defined in MARSSIM, section 2.2 in that the FSS unit was 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 Crib House/Forebay 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 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 each survey unit was subjected to FSS.

A Radiological Engineer (RE) performed a visual inspection and walk-down of the survey unit on 06/25/2016 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, Survey Unit Classification 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 Operational DCGLs, justifying a final survey unit classification of Class 3.

At the time of FSS, the Forebay was still submerged. Following completion of FSS and once compliance with the unrestricted release criteria is successfully demonstrated, the Forebay walls will be demolished to elevation 588 foot and the Forebay will be backfilled with clean fill, clean concrete debris, grout, or a combination of the three materials. The Circulating Water Intake piping has been filled with grout.

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.

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 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 Unit #B3-08100A 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 9) 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 10) 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.

Table 2 presents the ROC for the decommissioning of Crib House/Forebay structural surfaces and the normalized mixture fractions based on the radionuclide mixture.

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 Table 2 - Dose Significant Radionuclides and Mixture

% of Total Activity Radionuclide (normalized)(1)(2)

Co-60 0.92%

Cs-134 0.01%

Cs-137 75.32%

Ni-63 23.71%

Sr-90 0.05%

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

(2) Does not include dose significant radionuclides for activated concrete (H-3, Eu-152, Eu-154).

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 represent the 10 CFR 20.1402 dose criterion of 25 mrem/yr and are calculated for each ROC and each backfilled Basement.

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 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 Crib House/Forebay Basement survey unit are provided in Table 3. The IC dose percentage of 5% was used to adjust the Crib House/Forebay Basement DCGLs to account for the dose from the eliminated IC radionuclides.

Table 3 - Base Case DCGLs for Crib House/Forebay Basement Survey Unit (BcDCGLB)

Base Case DCGL Radionuclide (pCi/m2)

Co-60 5.52E+07 Cs-134 2.13E+07 Cs-137 2.96E+07 Ni-63 3.25E+09 Sr-90 1.16E+06 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.

The Operational DCGLs for the unrestricted release of the Crib House/Forebay Basement survey unit are provided in Table 4.

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 Table 4 - Operational DCGLs for Crib House/Forebay Basement Survey Unit (OpDCGLB)

Operational DCGL Radionuclide (pCi/m2)

Co-60 2.13E+07 Cs-134 8.20E+06 Cs-137 1.14E+07 Ni-63 1.25E+09 Sr-90 4.47E+05 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 was provided in procedure ZS-LT-300-001-001 Final Status Survey Package Development. The FSS plan uses an integrated sample design that combines scanning surveys and sampling which can be either random or judgmental.

The DQO process determined that Co-60, Ni-63, Sr-90, Cs-134 and Cs-137 would be the ROC in Survey Unit #B3-08100A. During FSS, concentrations for Hard-to-Detect (HTD)

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 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 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 FSS unless area specific ratios are determined by continuing characterization.

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 For the FSS of Survey Unit #B3-08100A, the surrogate Operational DCGLs for Co-60 and Cs-137 were computed based on the maximum ratios from Table 5.

The equation for calculating a surrogate DCGL is as follows:

Equation 1 1

=

1 2 3

+ + +

2 3 Where: DCGLSur = Surrogate radionuclide DCGL DCGL2,3n = DCGL for radionuclides to be represented by the surrogate Rn = Ratio of concentration (or nuclide mixture fraction) of radionuclide n to surrogate radionuclide Using the Operational DCGLs presented in Table 4 and the maximum ratios from Table 5, the following surrogate calculations were performed; Equation 2 1

(137) = = 1.08 + 07 /2 1 0.002 1.14 + 07 +

(137) 4.47 + 05(90)

The surrogate Operational DCGL that was used for Cs-137 in this survey unit for direct comparison of sample results to demonstrate compliance is 1.08E+07 Ci/m2.

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 Equation 3 1

(60) = = 5.23 + 06 /2 1 180.45 2.13 + 07 +

(60) 1.25 + 09(63)

The surrogate Operational DCGL that was used for Co-60 in this survey unit for direct comparison of sample results to demonstrate compliance is 5.23E+06 Ci/m2.

The action level for investigation in a Class 3 basement structure survey unit is 50% of the Operational DCGL. The surrogate DCGL for Co-60 while inferring Ni-63 is 5.23E+06 Ci/m2 and the surrogate DCGL for Cs-137 while inferring Sr-90 is 1.08E+07 Ci/m2.

The action levels for Survey Unit #B3-08100A are based on 50% of the DCGL and are presented in Table 6.

Table 6 - Action Levels for Survey Unit B3-08100A ROC DCGL (pCi/m2)

Co-60 (1) 2.61E+06 Cs-134 (2) 4.10E+06 Cs-137 (3) 5.40E+06 (1) Based on 50% of surrogate adjusted DCGL of 5.23E+06 Ci/m2 for Co-60 while inferring Ni-63 (2) Based on 50% of Operational DCGL (3) Based on 50% of surrogate adjusted DCGL of 1.08E+07 Ci/m2 for Cs-137 while inferring Sr-90 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 Unit #B3-08100A is a Class 3 basement survey unit 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

[19]

FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 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 Crib House was used for sigma () for the Crib House/Forebay.

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 relative shift (/) 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 Crib House/Forebay basement surface FSS unit was adjusted to meet the larger sample size. Table 7 presents the Crib House/Forebay basement surface FSS unit from LTP Chapter 5, Table 5-19 and the adjusted number of ISOCS measurements required.

Table 7 - 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)

Crib House/Forebay Class 3 138 14 392 3%

A Prospective Power Curve was generated using COMPASS, a software package developed under the sponsorship of the United States Nuclear Regulatory Commission (USNRC) for implementation of the MARSSIM in support of the decommissioning license termination rule (10CFR20, Subpart E). The result of the COMPASS computer run showed adequate power for the survey design. The survey design specified fourteen (14) ISOCS measurements for non-parametric statistical testing.

[20]

FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 As the survey unit was classified as Class 3, sample locations were selected at random.

The random locations 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 sample points. Measurement locations for the ISOCS measurements taken for random design are listed with the grid coordinates in Table 8.

Revision 1 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 Crib House/Forebay Basement walls and floors was completed prior to issuance of Revision 1 of the LTP, when this commitment was made. The upper levels of the Crib House have been demolished and removed and 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 twenty (20) concrete core samples taken from the 559 ft. elevation of the Crib House in March and April of 2012 during site characterization. No plant-derived radioactivity was positively identified at detectable concentrations in any of these samples.

Table 8 - Random ISOCS Measurement Locations MEASUREMENT ID GRID NO.

B3-08101A-FRWC-001-GM 666 B3-08101A-FRWC-002-GM 70 B3-08101A-FRWC-003-GM 1046 B3-08101A-FRFC-004-GM 208 B3-08101A-FRWC-005-GM 150 B3-08101A-FRWC-006-GM 742 B3-08101A-FRWC-007-GM 32 B3-08101A-FRWC-008-GM 251 B3-08101A-FRFC-009-GM 172 B3-08101A-FRWC-010-GM 1149 B3-08101A-FRWC-011-GM 286

[21]

FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 Table 8 (continued) - Random ISOCS Measurement Locations MEASUREMENT ID GRID NO.

B3-08101A-FRFC-012-GM 830 B3-08101A-FRWC-013-GM 429 B3-08101A-FRWC-014-GM 13 B3-08101A-FQWC-014-GM 13 Fourteen (14) ISOCS measurements were required for the non-parametric statistical test (sample size N = 14). The activity in the Unit 1 and Unit 2 Circulating Water Intake Pipes are included with the Crib House/Forebay Basement survey unit through the DCGL calculation. The Circulating Water Intake Pipes are located on the south end of the Turbine Building, beneath the Condenser Water Boxes, on 583 ft. elevation. Access to the Circulating Water Intake Pipes is very limited and therefore, these areas were surveyed as biased areas using judgmental samples. The area-weighted mean of the judgmental sample population in the Unit 1 and Unit 2 Circulating Water Intake Pipes was added to the random mean of the Crib House/Forebay FSS unit results (see section 14). Sample plans #B3-08102A-S and #B3-08102B-S were generated for the acquisition of the judgmental ISOCS measurements in these pipes.

The survey units for the Circulating Water Intake Pipes consisted of the east and west sections of both Unit 1 and Unit 2 Intake Pipes. The interior of each pipe has a surface area of 440m2 but the only accessible portions of the survey unit are the two vertical lengths of 9 diameter piping from 588 elevation to the 558 ft. elevation (approximate surface area of 158 m2). In order to allow access for the ISOCS, a hole was cut into each of the two pipes at the 588 elevation. The ISOCS was secured at 90 degrees looking down the 30 ft. length of pipe, resulting in a FOV of 78m2. Measurement locations for the ISOCS measurements taken for the Circulating Water Intake Pipes judgmental samples are listed with the grid coordinates in Table 9.

Table 9 - Circulating Water Intake Pipe Judgmental Sample Measurement Locations MEASUREMENT ID GRID NO.

B3-08102AS-FJSM-001-GD 01 B3-08102AS-FJSM-002-GD 02 B3-08102AS-FQSM-002-GD 02 B3-08102BS-FJSM-001-GD 01 B3-08102BS-FJSM-002-GD 02

[22]

FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 A map of the judgmental ISOCS measurement locations for the Circulating Water Intake Pipes is provided in Figure 3 in Attachment 1.

The Forebay surface area that was, and continues to be submerged, equated to a surface area of 5,407 m2, or 30% of the total surface area of the Crib House/Forebay Basement survey unit. While the surfaces of the Forebay were not accessible to random measurements, due to the large surface area involved, additional judgmental measurements were acquired of the submerged wall surfaces using scintillation detectors in dry tubes for FSS. Sample plan #B3-08401A-F was generated for the acquisition of 14 judgmental measurements at biased locations within the Forebay using this survey approach. The mechanics of the survey approach is further described in TSD 17-006.

Judgmental locations for the measurements taken with scintillation detectors inside the Forebay are listed with a description of the location in Table 10.

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 measurements taken in a survey unit with the locations selected at random. One ISOCS measurement, #B3-08101A-FQWC-014-GM was selected randomly for the replicate measurement. An additional replicate ISOCS measurement, #B3-08102AS-FQSM-002-GD was selected for the judgmental measurements taken in the Circulating Water Intake Pipe. As part of the Forebay survey, an additional replicate measurement was also acquired at location #B3-08401A-FJQC-014-GD.

Table 10 - Forebay Judgmental Sample Measurement Locations MEASUREMENT ID DESCRIPTION B3-08401A-FJWC-001-GD Pier 1, South Side, 2 feet below water line B3-08401A-FJWC-002-GD Pier 2, North Side, 2 feet below water line B3-08401A-FJWC-003-GD Pier 2, South Side, 2 feet below water line B3-08401A-FJWC-004-GD Pier 3, North Side, 2 feet below water line B3-08401A-FJWC-005-GD Pier 3, South Side, 2 feet below water line B3-08401A-FJWC-006-GD Pier 4, North Side, 2 feet below water line B3-08401A-FJWC-007-GD Pier 4, South Side, 2 feet below water line B3-08401A-FJWC-008-GD Pier 5, North Side, 2 feet below water line B3-08401A-FJWC-009-GD 5th Screen Box, NW, 2 ft. below water line

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 Table 10 (continued) - Forebay Judgmental Sample Measurement Locations MEASUREMENT ID DESCRIPTION B3-08401A-FJWC-010-GD Southeast Wall corner, 2 ft. below water line B3-08401A-FJWC-011-GD East Wall Platform, 2 ft. below water line B3-08401A-FJWC-012-GD East Wall Platform, 2 ft. below water line B3-08401A-FJWC-013-GD East Wall Platform, 2 ft. below water line B3-08401A-FJWC-014-GD Northeast Wall corner, 2 ft. below water line B3-08401A-FJQC-014-GD Northeast Wall corner, 2 ft. below water line 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 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 7 specifies that a minimum of 392 m2 or 3% of the accessible surface area in this 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. Fourteen random (14) ISOCS measurements were taken of Crib House basement surfaces at a stand-off distance of 3 meters. This resulted in a FOV for each measurement of 28 m2. The total areal coverage represented by the 14 ISOCS measurements was 392 m2. In addition, 4 judgmental measurements were taken with the ISOCS secured at 90 degrees looking down the 30 ft.

length of Circulating Water Intake Pipe, resulting in a FOV for each measurement of 78 m2. These measurements added an additional surface area of 312 m2 to the surface area in this survey unit that was subjected to areal scan coverage. The 704 m2 area actually scanned (by ISOCS FOV) represents approximately 4% of the total surface area (18,254 m2) of the survey unit. A map of the surface area scanned by the ISOCS FOV is provided in Figure 3.

[24]

FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 For this Class 3 basement structure survey unit, the Investigation Levels for ISOCS measurement results are those levels specified in LTP Chapter 5, Table 5-25 and are reproduced below in Table 11.

Table 11 - Investigation Levels Classification Direct Measurement Class 3 >0.5 Operational DCGL Table 12 provides a synopsis of the survey design for Survey Unit #B3-08100A.

Table 12 - Synopsis of Survey Design FEATURE DESIGN CRITERIA BASIS Survey Unit Surface 18,254 m2 LTP Ch. 5, Table 5-23 Area

= 3.66E-09

UBGR = SOF of 1

LBGR = SOF of 0.01 Number of 14 (random)

Type I error = 0.05 Measurements (N)

Type II error = 0.05

/ = 3 (adjusted)

MARSSIM Table 5.5 (LTP Chapter 5, section Grid Spacing Random 5.6.4.5.2)

Co 2.13E+07 pCi/m2

Cs-134 - 8.20E+06 pCi/m2 Operational DCGLs for Crib DCGLs

Cs-137 - 1.14E+07 pCi/m2 House/Forebay,

Ni 1.25E+09 pCi/m2 (LTP Chapter 5, Table 5-4)

Sr 4.47E+05 pCi/m2 Investigation Level >0.5 Operational DCGL (LTP Chapter 5, Table 5-25)

Judgmental areal coverage, Scan Areal Coverage 704 m2 or ~4% areal coverage (LTP Chapter 5, Table 5-19) 3 measurements selected randomly for QC (LTP Chapter 5, section 5.9) replicate measurement analysis

[25]

FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100

6. SURVEY IMPLEMENTATION For Survey Unit #B3-08100A, compliance with the unrestricted release criteria was demonstrated through a combination of direct measurements using the ISOCS and direct measurements using scintillation detectors in dry tubes. LTP Chapter 5, section 5.1 states that if the concentration of residual gamma radioactivity in an individual measurement exceeds a SOF of 0.1, then a sample will be acquired of the elevated media and analyzed for HTD ROC. This threshold was not encountered during the FSS of Survey Unit #B3-08100A. Consequently, no additional samples were acquired for assessment of HTD ROC.

CRIB HOUSE BASEMENT STRUCTURE FSS field activities commenced in the Crib House basement under FSS Sample Plan #B3-08101A-F, which included DQOs, survey design, detailed FSS instructions, job safety analysis, and related procedures for reference. 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 four (4) working days to complete. Daily briefings were conducted to discuss the expectations for job performance and to review safety aspects of the job. The survey required field activities were performed during normal working hours starting on June 24, 2015 and concluding on June 27, 2015.

ZionSolutions TSD 14-022, Use of In-Situ Gamma Spectroscopy for Source Term Survey of End State Structures (Reference 12) 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 Crib House basement structure, the physical condition of the concrete surfaces to be surveyed were assessed to ensure that the geometry was not significantly changed from that assumed in TSD 14-022. All ISOCS measurements were acquired using the geometry labeled as CRIBHOUSE_3M, 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. 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. No additional adjustments to ISOCS geometry were deemed necessary.

The 14 random ISOCS measurement locations were marked based on grid coordinates provided by VSP. A replicate measurement was also acquired in the Crib House basement

[26]

FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 at location B3-08101A-FQWC-014-GM at grid #13. The ISOCS detector was oriented perpendicular to the surface of interest represented by the grid coordinate.

UNIT 1 AND UNIT 2 CIRCULATING WATER INTAKE PIPES Subsequent FSS field activities were conducted starting on September 16, 2015 under FSS Sample Plans #B3-08102A-S and #B3-08102B-S, which included the requisite DQOs, survey design, detailed FSS instructions, job safety analysis, and related procedures for obtaining ISOCS measurements within the Unit 1 and Unit 2 Circulating Water Intake Pipe for FSS. 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 four (4) working days to complete. Daily briefings were conducted to discuss the expectations for job performance and to review safety aspects of the job. The survey required field activities were performed during normal working hours starting on September 16, 2015 and concluding on September 17, 2015.

The Circulating Water Intake Pipes are located on the south end of the Turbine Building, beneath the Condenser Water Boxes, on the 583 ft. elevation. During facility operation, the Unit 1 and Unit 2 Circulating Water Intake Pipes provided cooling water from Lake Michigan to various heat exchangers and condensers in the Turbine Building. The area to be surveyed consisted of the east and west portions of both Intake Pipes. The only access to the interior of the pipe were the two vertical lengths of 9 ft. diameter pipe that ran from 588 ft. elevation to the 558 ft. elevation (approximate surface area of 158 m2). In order to allow access for insertion of the ISOCS, a hole was cut into each of these two pipes at the 588 ft. elevation. The ISOCS was then secured at 90 degrees looking down the 30 foot length of pipe.

Prior to implementing this sample plan, the physical geometry of the ISOCS measurements in the Circulating Water Intake Pipe were assessed to determine if the geometry were significantly different from that assumed in TSD 14-022. In accordance with the general approach and methods described in TSD 14-022, the efficiency calibrations for the ISOCS measurements in the Intake Pipe were modified to meet the unique geometry encountered in the pipes. The geometry assumed that the detector was positioned perpendicular inside of a cylinder with the exposed face of the detector positioned at a distance of 9.1 meters from the bottom of the pipe surface. The depth of contamination was assumed at 1/2 inch. All measurements were taken using Efficiency ID 3M_TURBINE, which assumed a FOV of 78 m2.

Two (2) judgmental ISOCS measurement locations were selected within the Unit 1 Circulating Water Intake Pipe and two (2) judgmental ISOCS measurement locations were

[27]

FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 selected within the Unit 2 Circulating Water Intake Pipe. A replicate measurement was also acquired in Unit 1 Circulating Water Intake Pipe at location B3-08102AS-FQSM-002-GD.

FOREBAY STRUCTURE FSS field activities were conducted in the Forebay under FSS Sample Plan #B3-08401A-F, which included DQOs, survey design, detailed FSS instructions, job safety analysis, and related procedures for reference. The Forebay is considered as part of the Crib House basement structure. During the FSS of the Crib House basement, the surface area of the Forebay was deemed as not accessible as it was flooded and directly hydraulically connected to Lake Michigan. Consequently, the selection of a Forebay surface for the acquisition of a random measurement was not possible. The 14 judgmental measurements taken under sample plan #B3-08401A-F in the Forebay were intended to supplement the FSS that was performed in the Crib House basement in June of 2015.

The radiological survey data that was acquired by the implementation of sample plan #B3-08401A-F was the result of specialized measurement methodology using scintillation detectors deployed in dry tubes. TSD 17-006 describes the basis for this methodology.

Prior to implementing this sample plan, the physical condition of the surfaces to be surveyed in the Forebay were assessed to determine if the geometry was significantly different from that assumed in TSD 17-006. The assessment confirmed that the geometry used for the efficiency calibrations was valid.

The scintillation detector was deployed vertically in a dry tube positioned adjacent to the surface of each designated measurement location. The FOV was equivalent to the surface area of the conformal source utilized during the detectors efficiency determination. Each survey measurement location was made reproducible by utilizing permanent markings on the Forebay walls above the waterline.

Measurements were acquired using this approach at fourteen (14) biased locations selected within the Forebay. A replicate measurement was also acquired at location B3-08401A-FJQC-014-GD.

7. SURVEY RESULTS Direct measurements were acquired at each random location in the Crib House basement and at the four judgmental locations in the Circulating Water Intake Pipe using the ISOCS.

A summary of the results of the fourteen (14) ISOCS measurements taken for non-parametric statistical testing results is provided in Table 13. The concentrations for Ni-63 and Sr-90 are inferred based on the maximum ratios as specified in Table 5. The complete

[28]

FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 ISOCS gamma spectroscopy reports are presented in Attachment 3. The basic statistics for the random measurements are summarized in Table 14.

Table 13 - Summary of Gamma Spectroscopy Results for ISOCS Measurements Comprising the Statistical Sample Population Co-60 Cs-134 Cs-137 Ni-63 Sr-90 MEASUREMENT ID 2 2 2 2 (pCi/m ) (pCi/m ) (pCi/m ) (pCi/m ) (pCi/m2)

B3-08101A-FRWC-001-GM 0.00E+00 1.74E+02 2.78E+02 0.00E+00 5.56E-01 B3-08101A-FRWC-002-GM 0.00E+00 4.99E+01 1.73E+01 0.00E+00 3.46E-01 B3-08101A-FRWC-003-GM 1.02E+02 1.07E+01 5.54E+01 1.84E+04 1.11E-01 B3-08101A-FRFC-004-GM 1.84E+02 3.88E+01 1.00E+02 3.33E+04 2.01E-01 B3-08101A-FRWC-005-GM 0.00E+00 1.23E+02 0.00E+00 0.00E+00 0.00E+00 B3-08101A-FRWC-006-GM 1.52E+02 0.00E+00 1.75E+02 2.74E+04 3.49E-01 B3-08101A-FRWC-007-GM 0.00E+00 9.15E+01 9.17E+01 0.00E+00 1.83E-01 B3-08101A-FRWC-008-GM 3.44E+01 2.69E+02 0.00E+00 6.20E+03 0.00E+00 B3-08101A-FRFC-009-GM 1.44E+02 0.00E+00 0.00E+00 2.59E+04 0.00E+00 B3-08101A-FRWC-010-GM 9.72E+01 2.13E+01 0.00E+00 1.75E+04 0.00E+00 B3-08101A-FRWC-011-GM 5.30E+01 2.22E+01 6.57E+01 9.57E+03 1.31E-01 B3-08101A-FRFC-012-GM 5.53E+01 9.56E+00 3.24E+01 9.97E+03 6.48E-02 B3-08101A-FRWC-013-GM 2.86E+01 1.68E+02 0.00E+00 5.16E+03 0.00E+00 B3-08101A-FRWC-014-GM 7.28E+00 0.00E+00 0.00E+00 1.31E+03 0.00E+00 Table 14 - 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 6.12E+01 4.37E+01 1.84E+02 0.00E+00 6.38E+01 5.52E+07 1.11E-06 2.77E-05 Cs-134 6.98E+01 3.05E+01 2.69E+02 0.00E+00 8.37E+01 2.13E+07 3.28E-06 8.19E-05 Cs-137 5.82E+01 2.49E+01 2.78E+02 0.00E+00 8.20E+01 2.96E+07 1.97E-06 4.92E-05 Ni-63 1.10E+04 7.88E+03 3.33E+04 0.00E+00 1.15E+04 3.25E+09 3.40E-06 8.50E-05 Sr-90 1.16E-01 4.97E-02 5.56E-01 0.00E+00 1.64E-01 1.16E+06 1.00E-07 2.51E-06 The mean BcSOF from random measurements taken on basement structural surfaces in survey unit #B3-08100A is 9.85E-06. This is derived by summing the average SOF per ROC resulting from the average concentration in Table 14. There were no identified elevated areas.

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 The implementation of required QC measures included the collection of one additional ISOCS measurement at location #14 (B3-08101A-FQWC-014-GM) for replicate measurement analysis. The replicate ISOCS measurement results are provided in Table

15. The concentration for Ni-63 and Sr-90 are inferred based on the maximum ratios as specified in Table 5.

Table 15 - Summary of ISOCS Replicate Measurement for QC Co-60 Cs-134 Cs-137 Ni-63 Sr-90 MEASUREMENT ID (pCi/m2) (pCi/m2) (pCi/m2) (pCi/m2) (pCi/m2)

B3-08101A-FQWC-014-GM 7.95E+01 7.98E+01 4.89E+01 1.44E+04 9.78E+05 Two (2) judgmental ISOCS measurements were taken within the Unit 1 Circulating Water Intake Pipe and 2 judgmental ISOCS measurements were taken within the Unit 2 Circulating Water Intake Pipe. A summary of the results of the 4 judgmental ISOCS measurements taken within the Circulating Water Intake Pipes are provided in Table 16.

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 3.

Table 16 - Summary of Gamma Spectroscopy Results for Judgmental ISOCS Measurements Taken in Circulating Water Intake Pipes Co-60 Cs-134 Cs-137 Ni-63 Sr-90 MEASUREMENT ID (pCi/m2) (pCi/m2) (pCi/m2) (pCi/m2) (pCi/m2)

B3-08102AS-FJSM-001-GD 1.20E+02 1.38E+03 1.90E+02 2.16E+04 3.80E-01 B3-08102AS-FJSM-002-GD 0.00E+00 4.59E+02 2.64E+02 0.00E+00 5.28E-01 B3-08102BS-FJSM-001-GD 4.20E+03 2.30E+02 6.16E+02 7.58E+05 1.23E+00 B3-08102BS-FJSM-002-GD 3.16E+04 2.78E+02 2.08E+03 5.71E+06 4.15E+00 A replicate ISOCS measurement was also acquired in Unit 1 Circulating Water Intake Pipe at location B3-08102AS-FQSM-002-GD. A summary of the results for the QC replicate measurement is provided in Table 17. The concentration for Ni-63 and Sr-90 are inferred based on the maximum ratios as specified in Table 5.

Table 17 - Summary of ISOCS Replicate Measurement for QC Co-60 Cs-134 Cs-137 Ni-63 Sr-90 MEASUREMENT ID 2 2 2 (pCi/m ) (pCi/m ) (pCi/m ) (pCi/m2) (pCi/m2)

B3-08102AS-FQSM-002-GD 3.61E+01 0.00E+00 0.00E+00 6.52E+04 0.00E+00

[30]

FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 Fourteen (14) judgmental measurements were taken within the Forebay using scintillation detectors deployed in dry tubes. A summary of the results of the 14 judgmental measurements taken within the Forebay are provided in Table 18. Each measurement represents the net gamma result at that location in units of pCi/m2. Using the normalized gamma mixture from Table 2, a concentration for each of the gamma emitting ROC was calculated. The concentrations for Ni-63 and Sr-90 were then inferred based on the maximum ratios as specified in Table 5.

Table 18 - Summary of Results for Judgmental Measurements Taken in the Forebay Co-60 Cs-134 Cs-137 Ni-63 Sr-90 MEASUREMENT ID (pCi/m2) (pCi/m2) (pCi/m2) (pCi/m2) (pCi/m2)

B3-08401A-FJWC-001-GD 6.48E+03 7.08E+01 5.33E+05 1.17E+06 1.07E+03 B3-08401A-FJWC-002-GD 6.65E+03 7.27E+01 5.48E+05 1.20E+06 1.10E+03 B3-08401A-FJWC-003-GD 6.46E+03 7.06E+01 5.32E+05 1.17E+06 1.06E+03 B3-08401A-FJWC-004-GD 6.74E+03 7.37E+01 5.55E+05 1.22E+06 1.11E+03 B3-08401A-FJWC-005-GD 5.78E+03 6.32E+01 4.76E+05 1.04E+06 9.52E+02 B3-08401A-FJWC-006-GD 6.15E+03 6.73E+01 5.07E+05 1.11E+06 1.01E+03 B3-08401A-FJWC-007-GD 6.65E+03 7.27E+01 5.48E+05 1.20E+06 1.10E+03 B3-08401A-FJWC-008-GD 5.96E+03 6.51E+01 4.90E+05 1.08E+06 9.81E+02 B3-08401A-FJWC-009-GD 7.11E+03 7.77E+01 5.85E+05 1.28E+06 1.17E+03 B3-08401A-FJWC-010-GD 7.11E+03 7.77E+01 5.85E+05 1.28E+06 1.17E+03 B3-08401A-FJWC-011-GD 6.96E+03 7.61E+01 5.73E+05 1.26E+06 1.15E+03 B3-08401A-FJWC-012-GD 7.15E+03 7.82E+01 5.89E+05 1.29E+06 1.18E+03 B3-08401A-FJWC-013-GD 6.52E+03 7.13E+01 5.37E+05 1.18E+06 1.07E+03 B3-08401A-FJWC-014-GD 8.22E+03 8.98E+01 6.77E+05 1.48E+06 1.35E+03 A replicate measurement was acquired in the Forebay at location B3-08401A-FJQC-014-GD. A summary of the results for the QC replicate measurement is provided in Table 19.

Table 19 - Summary of Replicate Measurement Taken in Forebay for QC Co-60 Cs-134 Cs-137 Ni-63 Sr-90 MEASUREMENT ID 2 2 2 2 (pCi/m ) (pCi/m ) (pCi/m ) (pCi/m ) (pCi/m2)

B3-08401A-FJQC-014-GD 8.61E+03 9.41E+01 7.09E+05 1.55E+06 1.42E+03

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 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 results of the unity rule calculation for the ROC for the random ISOCS measurements for Survey Unit #B3-08100A using Operational DCGLs are provided in Table 20.

Table 20 - Sum-of-Fractions for Random ISOCS Measurements FRACTION OF OPERATIONAL DCGL MEASUREMENT ID SOF Co-60 Cs-134 Cs-137 Ni-63 Sr-90 B3-08101A-FRWC-001-GM 0.00E+00 2.12E-05 2.44E-05 0.00E+00 1.24E-06 4.68E-05 B3-08101A-FRWC-002-GM 0.00E+00 6.08E-06 1.52E-06 0.00E+00 7.74E-08 7.68E-06 B3-08101A-FRWC-003-GM 4.78E-06 1.30E-06 4.86E-06 1.47E-05 2.48E-07 2.59E-05 B3-08101A-FRFC-004-GM 8.65E-06 4.73E-06 8.81E-06 2.66E-05 4.49E-07 4.92E-05 B3-08101A-FRWC-005-GM 0.00E+00 1.50E-05 0.00E+00 0.00E+00 0.00E+00 1.50E-05 B3-08101A-FRWC-006-GM 7.12E-06 0.00E+00 1.53E-05 2.19E-05 7.81E-07 4.51E-05 B3-08101A-FRWC-007-GM 0.00E+00 1.12E-05 8.04E-06 0.00E+00 4.10E-07 1.96E-05 B3-08101A-FRWC-008-GM 1.61E-06 3.28E-05 0.00E+00 4.96E-06 0.00E+00 3.94E-05 B3-08101A-FRFC-009-GM 6.75E-06 0.00E+00 0.00E+00 2.07E-05 0.00E+00 2.75E-05 B3-08101A-FRWC-010-GM 4.56E-06 2.59E-06 0.00E+00 1.40E-05 0.00E+00 2.12E-05 B3-08101A-FRWC-011-GM 2.49E-06 2.70E-06 5.77E-06 7.66E-06 2.94E-07 1.89E-05 B3-08101A-FRFC-012-GM 2.60E-06 1.17E-06 2.84E-06 7.89E-06 1.45E-07 1.47E-05 B3-08101A-FRWC-013-GM 1.34E-06 2.05E-05 0.00E+00 4.13E-06 0.00E+00 2.59E-05 B3-08101A-FRWC-014-GM 3.42E-07 0.00E+00 0.00E+00 1.05E-06 0.00E+00 1.39E-06 B3-08101A-FQWC-014-GM 3.73E-06 9.73E-06 4.29E-06 1.15E-05 2.19E-07 2.94E-05 Number of Random Measurements = 14 # of Random Measurements with SOF > 1 = 0 Max Individual Random Measurement SOF = 4.92E-05 Mean Random Measurement SOF = 2.56E-05 The results of the unity rule calculation for the judgmental ISOCS measurements taken in the Circulating Water Intake Pipe using Operational DCGLs are provided in Table 21.

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 Table 21 - Sum-of-Fractions for Judgmental ISOCS Measurements Taken in the Circulating Water Intake Pipe FRACTION OF OPERATIONAL DCGL MEASUREMENT ID SOF Co-60 Cs-134 Cs-137 Ni-63 Sr-90 B3-08102AS-FJSM-001-GD 5.26E-06 1.68E-04 1.67E-05 1.73E-05 8.50E-07 2.08E-04 B3-08102AS-FJSM-002-GD 0.00E+00 5.60E-05 2.31E-05 0.00E+00 1.18E-06 8.03E-05 B3-08102AS-FQSM-002-GD 1.70E-05 0.00E+00 0.00E+00 5.21E-05 0.00E+00 6.91E-05 B3-08102BS-FJSM-001-GD 1.97E-04 2.80E-05 5.40E-05 6.07E-04 2.75E-06 8.89E-04 B3-08102BS-FJSM-002-GD 1.49E-03 3.39E-05 1.82E-04 4.57E-03 9.28E-06 6.28E-03 Number of Judgmental Measurements = 4 # of Judgmental Measurements with SOF > 1 = 0 Max Individual Judgmental Measurement SOF = 6.28E-03 Mean Judgmental Measurement SOF = 1.86E-03 The results of the unity rule calculation for the judgmental ISOCS measurements taken in the Circulating Water Intake Pipe using the Operational DCGLs are provided in Table 22.

Table 22 - Sum-of-Fractions for Judgmental Gamma Measurements Taken in the Forebay FRACTION OF OPERATIONAL DCGL MEASUREMENT ID SOF Co-60 Cs-134 Cs-137 Ni-63 Sr-90 B3-08401A-FJWC-001-GD 3.04E-04 8.64E-06 4.68E-02 9.35E-04 2.39E-03 5.04E-02 B3-08401A-FJWC-002-GD 3.12E-04 8.87E-06 4.80E-02 9.60E-04 2.45E-03 5.18E-02 B3-08401A-FJWC-003-GD 3.03E-04 8.61E-06 4.66E-02 9.32E-04 2.38E-03 5.03E-02 B3-08401A-FJWC-004-GD 3.16E-04 8.98E-06 4.87E-02 9.73E-04 2.48E-03 5.25E-02 B3-08401A-FJWC-005-GD 2.72E-04 7.71E-06 4.18E-02 8.35E-04 2.13E-03 4.50E-02 B3-08401A-FJWC-006-GD 2.89E-04 8.20E-06 4.44E-02 8.88E-04 2.27E-03 4.79E-02 B3-08401A-FJWC-007-GD 3.12E-04 8.87E-06 4.80E-02 9.60E-04 2.45E-03 5.18E-02 B3-08401A-FJWC-008-GD 2.80E-04 7.94E-06 4.30E-02 8.60E-04 2.19E-03 4.64E-02 B3-08401A-FJWC-009-GD 3.34E-04 9.48E-06 5.13E-02 1.03E-03 2.62E-03 5.53E-02 B3-08401A-FJWC-010-GD 3.34E-04 9.48E-06 5.13E-02 1.03E-03 2.62E-03 5.53E-02 B3-08401A-FJWC-011-GD 3.27E-04 9.27E-06 5.02E-02 1.00E-03 2.56E-03 5.42E-02 B3-08401A-FJWC-012-GD 3.36E-04 9.54E-06 5.17E-02 1.03E-03 2.64E-03 5.57E-02 B3-08401A-FJWC-013-GD 3.06E-04 8.69E-06 4.71E-02 9.42E-04 2.40E-03 5.08E-02 B3-08401A-FJWC-014-GD 3.86E-04 1.10E-05 5.94E-02 1.19E-03 3.03E-03 6.40E-02 B3-08401A-FJQC-014-GD 4.04E-04 1.15E-05 6.22E-02 1.24E-03 3.17E-03 6.70E-02 Number of Judgmental Measurements = 14 # of Judgmental Measurements with SOF > 1 = 0 Max Individual Judgmental Measurement SOF = 6.40E-02 Mean Judgmental Measurement SOF = 5.32E-02

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 In order to assess the dose contribution from the Circulating Water Intake Pipe and the Forebay, the concentration of each ROC in each judgmental measurement was also compared against the respective Base Case DCGLs. This was accomplished using the same method that was used to calculate the mean SOF for the random measurements. The calculation of the mean SOF for the Circulating Water Intake Pipe is presented in Table 23 and the calculation of the mean SOF for the Forebay is presented in Table 24.

Table 23 - Calculation of Mean Sum-of-Fractions for Judgmental Measurements Taken in the Circulating Water Intake Pipe Using Base Case DCGLs Mean BcDCGL Avg SOF ROC (pCi/m ) (pCi/m2) per ROC 2

Co-60 8.99E+03 5.52E+07 1.63E-04 Cs-134 5.86E+02 2.13E+07 2.75E-05 Cs-137 7.86E+02 2.96E+07 2.66E-05 Ni-63 1.62E+06 3.25E+09 4.99E-04 Sr-90 1.57E+00 1.16E+06 1.36E-06 7.17E-04 Mean SOF Table 24 - Calculation of Mean Sum-of-Fractions for Judgmental Measurements Taken in the Forebay Using Base Case DCGLs Mean BcDCGL Avg SOF ROC (pCi/m ) (pCi/m2) per ROC 2

Co-60 6.71E+03 5.52E+07 1.22E-04 Cs-134 7.34E+01 2.13E+07 3.44E-06 Cs-137 5.52E+05 2.96E+07 1.87E-02 Ni-63 1.21E+06 3.25E+09 3.73E-04 Sr-90 1.10E+03 1.16E+06 9.53E-04 2.01E-02 Mean SOF

8. QUALITY CONTROL Three (3) duplicate measurements were taken during the FSS of this basement structure.

Measurement #B3-08101A-FQWC-014-GM was taken with the random measurement population acquired in the Crib House basement, measurement #B3-08102AS-FQSM-002-GD was taken with the judgmental measurements taken in the Circulating Water Intake Pipes and measurement #B3-08401A-FJQC-014-GD was taken with the judgmental gamma measurements taken in the Forebay. The measurement results were evaluated using USNRC acceptance criteria specified in Inspection Procedure No. 84750, Radioactive Waste Treatment, and Effluent and Environmental Monitoring (Reference

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 13). There was acceptable agreement between replicate measurement results taken in the Crib House basement and in the Forebay. Comparison of the duplicate ISOCS measurements collected from measurement location #2 inside the Unit 1 Circulating Water Intake Pipe was inconclusive. The Cs-137 concentration for both measurements was less than instrument MDC. The reported result for the comparison measurement was a negative value (-1.759E+02 pCi/m2, thus resulting in a reported concentration of 0.00E+00 pCi/m2). K-40 could not be substituted as the comparison measurement was also negative. As two additional QC samples were taken in this survey unit with acceptable comparison, no further action was deemed necessary. Refer to Attachment 5 for data and quality control analysis results.

9. INVESTIGATIONS AND RESULTS No measurements were taken for an investigation during the performance of FSS in this survey unit.

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 in soil was ALARA.

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

12. DATA QUALITY ASSESSMENT (DQA)

The DQO sample design and data were reviewed in accordance with ZionSolutions procedure ZS-LT-300-001-004, Final Status Survey Data Assessment (Reference 14) for completeness and consistency. Documentation was complete and legible. Surveys and the collection of measurements were consistent with the DQOs and were sufficient to ensure that the survey unit was properly designated as Class 3. The survey design had adequate power as indicated by the Retrospective Power Curve.

The analytical results of all samples were less than a SOF of one. Additionally, the maximum activity for each ROC did not exceed 10% of their respective Operational DCGL for the Crib House/Forebay.

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 Although MARSSIM states that the Sign Test need not be performed in the instance that no measurements surpass the DCGL, the test was conducted to demonstrate coherence to the statistical principles of the DQO process. 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 7.

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

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 systematic 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

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 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 Crib House/Forebay is 1.57 mrem/yr, which equates to a SOF of 0.0628.

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 DCGL for the Crib House/Forebay accounts for the activity in the Circulating Water Intake Pipes by summing the surface areas. In accordance with LTP Chapter 6, Table 6-23, the combined summed surface area of the Crib House/Forebay and Circulating Water Intake Pipe is 18,254 m2. The total area is broken down as follows; the Crib House has a surface area of 8,435 m2, the Circulating Water Intake Pipe has a surface area of 4,412 m2 and the Forebay has a surface area of 5,407 m2. Area weighting using Equation 5-9 from LTP Chapter 5 was used to sum the residual activity in the Crib House structure, Forebay structure and Circulating Water Intake Pipes on an area-weighted basis.

The result is provided in Equation 5.

Equation 5 8,435 4,412 5,407 (9.85 06 ) + (7.17 04 ) + (2.01 02 ) = 0.0061 18,254 18,254 18,254 The adjusted BcSOF for the Crib House/Forebay basement structure is 0.0061. This equates to a dose of 0.1525 mrem/yr. The adjusted BcSOF for the Crib House/Forebay is then used in the following equation to calculate BcSOFBASEMENT for the Crib House/Forebay.

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 Equation 6

= + + +

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)

There are no penetrations or embedded pipe associated with the Crib House/Forebay basement. Consequently, the dose contribution from both (variables BcSOFEP and BcSOFPN) are zero.

The BcSOFBASEMENT value for the Crib House/Forebay is then derived as follows; Equation 8

= 0.0061 + 0.0000 + 0.00000 + 0.0628 = 0.0689 The BcSOFBASEMENT for the Crib House/Forebay basement is 0.0689. This SOF equates to a dose of 1.7225 mrem/yr TEDE to an AMCG from residual radioactivity in the Crib House/Forebay basement.

15. CONCLUSION Survey Unit #B3-08100A has met the DQOs of the FSS plan. 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 ROC concentration

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 values exceeds the Operational DCGL or any investigational levels; 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 unit is properly classified as Class 3.

The dose contribution from structural surfaces in Survey Unit #B3-08100A, Crib House/Forebay Basement, is 0.1525 mrem/yr TEDE, based on the average concentration of the ROC in samples used for non-parametric statistical sampling as well as judgmental measurements taken in the Forebay and the Circulating Water Intake Pipes on an area-weighted basis. The dose from embedded pipe and penetrations in the Crib House/Forebay is zero and the dose from clean fill is 1.57 mrem/yr. The total dose attributed to the Crib House/Forebay as a summation of all dose components is 1.7225 mrem/yr.

Survey Unit # B3-08100A, Crib House/Forebay Basement is acceptable for unrestricted release.

16. REFERENCES

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

2. Zion Station Restoration Project License Termination Plan

3. ZionSolutions procedure 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 17-006, Underwater Survey Methodology for Zion Nuclear Station Crib House/Forebay Basement Final Status Survey Unit

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

7. Zion Station Historical Site Assessment (HSA)

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

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

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

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100

11. ZionSolutions ZS-LT-01, Quality Assurance Project Plan (for Characterization and FSS) (QAPP)

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

13. U.S. NRC Inspection Procedure No. 84750, Radioactive Waste Treatment, and Effluent and Environmental Monitoring

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

17. ATTACHMENTS Attachment 1 - Figure and Maps Attachment 2 - ISOCS Geometry Attachment 3 - ISOCS Analytical Reports Attachment 4 - Sign Test Attachment 5 - Forebay Judgmental Measurements Attachment 6 - QC Measurement Assessments Attachment 7 - Graphical Presentations

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY ATTACHMENT 1 FIGURES AND MAPS

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Forebay - Figure 1 001 003 007 South side South side South side 2 feet 2 feet 2 feet below below below water line water line water line 005 South side 2 feet below water line 002 004 006 008 North side North side North side North side 2 feet 2 feet 2 feet 2 feet below below below below water line water line water line water line

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Forebay - Figure 2 Forebay - Figure 3 009 2 feet below water line

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Forebay - Figure 4 010 2 feet below water line 011 2 feet below water line

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Forebay - Figure 5 013 012 2 feet 2 feet below below water line water line

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Forebay - Figure 6 014 (QC) 014 2 feet 2 feet below below water line water line

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Forebay - Figure 7 009 2 feet below water line

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 ATTACHMENT 2 ISOCS Geometry

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 ATTACHMENT 3 ISOCS ANALYTICAL REPORTS

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FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 ATTACHMENT 4 SIGN TEST

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Survey Area 08000 Description Crib House/Forebay FSS Survey Unit 08101 Description Crib House/Forebay Structural Basement Classification 3 Type I Error 0.05 Number of Measurements 14 SOF

1-Ws Sign (Ws) 1 0.00005 1.00 +1 2 0.00001 1.00 +1 3 0.00003 1.00 +1 4 0.00005 1.00 +1 5 0.00002 1.00 +1 6 0.00005 1.00 +1 7 0.00002 1.00 +1 8 0.00004 1.00 +1 9 0.00003 1.00 +1 10 0.00002 1.00 +1 11 0.00002 1.00 +1 12 0.00001 1.00 +1 13 0.00003 1.00 +1 14 0.00000 1.00 +1 Number of positive differences (S+) 14 Critical Value 10 Survey Unit Meets the Acceptance Criteria Prepared by (RE): Dan Mihalik 11/27/2018 (Print Name) (Signature) (Date)

Peer Reviewed by (RE): Gerry Wood 11/27/2018 (Print Name) (Signature) (Date)

[202]

FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 ATTACHMENT 5 FOREBAY JUDGMENTAL MEASUREMENTS

[203]

Measurement Location MDC dpm/cm2 MDC pCi/cm2 MDC dpm/100cm2MDC pCi/100cm2 MDC dpm/1m2 MDC pCi/1m2 BKGD CPM GCPM NCPM eff. NET DPM net dpm/cm2 net pCi/cm2 netdpm/100cm2 net pCi/100cm2 net dpm/m2 net pCi/m2 B3-08401A-FJWC-001-GD 58 26 5793 2609 579276 260935 72 370 298 0.003 116270 120 54 11988 5400 1198783 539992 B3-08401A-FJWC-002-GD 58 26 5793 2609 579276 260935 72 378 306 0.003 119391 123 55 12310 5545 1230965 554488 B3-08401A-FJWC-003-GD 58 26 5793 2609 579276 260935 72 369 297 0.003 115880 119 54 11948 5382 1194761 538180 B3-08401A-FJWC-004-GD 58 26 5793 2609 579276 260935 72 382 310 0.003 120952 125 56 12471 5617 1247056 561737 B3-08401A-FJWC-005-GD 58 26 5793 2609 579276 260935 72 338 266 0.003 103785 107 48 10701 4820 1070055 482006 B3-08401A-FJWC-006-GD 52 24 5230 2356 522961 235568 65 348 283 0.003 110417 114 51 11384 5128 1138442 512811 B3-08401A-FJWC-007-GD 52 24 5230 2356 522961 235568 65 371 306 0.003 119391 123 55 12310 5545 1230965 554488 B3-08401A-FJWC-008-GD 52 24 5230 2356 522961 235568 65 339 274 0.003 106906 110 50 11022 4965 1102237 496503 B3-08401A-FJWC-009-GD 52 24 5230 2356 522961 235568 65 392 327 0.003 127585 132 59 13154 5925 1315443 592542 B3-08401A-FJWC-010-GD 58 26 5793 2609 579276 260935 72 399 327 0.003 127585 132 59 13154 5925 1315443 592542 B3-08401A-FJWC-011-GD 52 24 5230 2356 522961 235568 65 385 320 0.003 124854 129 58 12873 5799 1287284 579857 B3-08401A-FJWC-012-GD 52 24 5230 2356 522961 235568 65 394 329 0.003 128365 132 60 13235 5962 1323489 596166 B3-08401A-FJWC-013-GD 52 24 5230 2356 522961 235568 65 365 300 0.003 117050 121 54 12068 5436 1206829 543616 B3-08401A-FJWC-014-GD 58 26 5793 2609 579276 260935 72 450 378 0.003 147483 152 68 15206 6850 1520604 684956 B3-08401A-FJQC-014-GD 52 24 5230 2356 522961 235568 65 461 396 0.003 154506 159 72 15930 7176 1593014 717573 Inferred using Normalized Mixture Mixture Measurement Location pCi/m2 Co-60 Cs-134 Cs-137 pCi/m2 pCi/m2 pCi/m2 B3-08401A-FJWC-001-GD 5.40E+05 6.48E+03 7.08E+01 5.33E+05 B3-08401A-FJWC-002-GD 5.54E+05 6.65E+03 7.27E+01 5.48E+05 B3-08401A-FJWC-003-GD 5.38E+05 6.46E+03 7.06E+01 5.32E+05 B3-08401A-FJWC-004-GD 5.62E+05 6.74E+03 7.37E+01 5.55E+05 B3-08401A-FJWC-005-GD 4.82E+05 5.78E+03 6.32E+01 4.76E+05 B3-08401A-FJWC-006-GD 5.13E+05 6.15E+03 6.73E+01 5.07E+05 B3-08401A-FJWC-007-GD 5.54E+05 6.65E+03 7.27E+01 5.48E+05 B3-08401A-FJWC-008-GD 4.97E+05 5.96E+03 6.51E+01 4.90E+05 B3-08401A-FJWC-009-GD 5.93E+05 7.11E+03 7.77E+01 5.85E+05 B3-08401A-FJWC-010-GD 5.93E+05 7.11E+03 7.77E+01 5.85E+05 B3-08401A-FJWC-011-GD 5.80E+05 6.96E+03 7.61E+01 5.73E+05 B3-08401A-FJWC-012-GD 5.96E+05 7.15E+03 7.82E+01 5.89E+05 B3-08401A-FJWC-013-GD 5.44E+05 6.52E+03 7.13E+01 5.37E+05 B3-08401A-FJWC-014-GD 6.85E+05 8.22E+03 8.98E+01 6.77E+05 B3-08401A-FJQC-014-GD 7.18E+05 8.61E+03 9.41E+01 7.09E+05

[204]

FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 ATTACHMENT 6 QC MEASUREMENT ASSESSMENTS

[205]

FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 Replicate Measurement Assessment Survey Unit # 08000 Survey Unit Name Crib House/Forebay Basement Sample Plan # B308101A Sample

Description:

Comparison of duplicate ISOCS measurements collected from measurement location #10. The standard measurement was B3-08101AF-RWC-014-GM, the comparison sample was B3-08101AF-QWC-014-GM.

STANDARD COMPARISON ROC Activity Standard Resolution Agreement Activity Standard Comparison Acceptable Value Error Range Value Error Ratio (Y/N)

Cs-137 0.00E+00 2.38E+02 0.00 0.5 - 2.0 7.83E+01 1.76E+02 0 N K-40 4.12E+04 6.36E+03 6.47 0.5 - 2.0 3.71E+04 5.63E+03 0.899732945 Y Comments/Corrective Actions: The Cs-137 Table is provided to show acceptance criteria concentration for both measurements was less used to assess split samples.

than instrument MDC. The reported result for the standard measurement was a negative value

(-1.035E+02 pCi/m2, thus resulting in a reported concentration of 0.00E+00 pCi/m2).

Consequently, as insufficient data was reported for Cs-137, K-40 was substituted for the comparison. There was acceptable agreement when using K-40. No further action is necessary.

Performed Date: Reviewed by: Date:

By:

G.L. Wood 09/26/17 D Wojtkowiak 09/27/17

[206]

FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 Replicate Measurement Assessment Survey Unit # 08000 Survey Unit Name Circ Water Intake Pipe Sample Plan # B308102S Sample

Description:

Comparison of duplicate ISOCS measurements collected from measurement location #2 inside the Unit 1 Circ Water Intake Pipe. The standard measurement was B3-08102AS-FJSM-002-GD, the comparison sample was B3-08102AS-FQSM-002-GD.

STANDARD COMPARISON ROC Activity Standard Resolution Agreement Activity Standard Comparison Acceptable Value Error Range Value Error Ratio (Y/N)

Cs-137 2.64E+02 2.54E+03 0.10 0.5 - 2.0 0.00E+00 2.27E+03 0 N Comments/Corrective Actions: The Cs-137 Table is provided to show acceptance criteria concentration for both measurements was less used to assess split samples.

than instrument MDC. The reported result for the comparison measurement was a negative value

(-1.759E+02 pCi/m2, thus resulting in a reported concentration of 0.00E+00 pCi/m2).

Consequently, as insufficient data was reported for Cs-137, K-40 could not be substituted as the comparison measurement was also negative. As two additional QC samples were taken in this survey unit with acceptable comparison, no further action was deemed necessary Performed Date: Reviewed by: Date:

By:

G.L. Wood 09/26/17 D Wojtkowiak 09/27/17

[207]

FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 Replicate Measurement Assessment Survey Unit # 08000 Survey Unit Name Forebay Sample Plan # B308401AF Sample

Description:

Comparison of duplicate NaI measurements collected from measurement location #14 in the Forebay. The standard measurement was B3-08401A-FJWC-014-GD, the comparison sample was B3-08401A-FJQC-014-GD.

STANDARD COMPARISON ROC Activity Standard Resolutio Agreement Activity Standard Comparison Acceptable Value Error n Range Value Error Ratio (Y/N)

Gross 6.85E+05 N/A N/A +20% 7.18E+05 N/A N/A Y Comments/Corrective Actions: The Cs-137 Table is provided to show acceptance criteria concentration for both measurements was inferred used to assess split samples.

from gross gamma results using the non-activated mixture from LTP Table 5-2. As the standard agreement method was not applicable to gross gamma results, the samples were in agreement if the gross gamma values were with + 20%. The gross gamma values were within 6%.

Consequently, the agreement between the two measurements were deemed acceptable.

Performed Date: Reviewed by: Date:

By:

G.L. Wood 09/26/17 D Wojtkowiak 09/27/17

[208]

FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 ATTACHMENT 7 GRAPHICAL PRESENTATIONS

[209]

FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 Quantile Plot for Co-60 Survey Unit: B308101A

Description:

CRIB HOUSE/FOREBAY STRUCTURAL Mean: 6.12E+01 pCi/m2 Quantile Plot For Co-60 2.00E+02 1.80E+02 1.60E+02 Concentration (pCi/m2) 1.40E+02 1.20E+02 1.00E+02 8.00E+01 6.00E+01 4.00E+01 2.00E+01 0.00E+00 0% 20% 40% 60% 80% 100%

Percentage

[210]

FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 Quantile Plot for Cs-137 Survey Unit: B308101A

Description:

CRIB HOUSE/FOREBAY STRUCTURAL Mean: 5.82E+01 pCi/m2 Quantile Plot For Cs-137 3.00E+02 2.50E+02 Concentration (pCi/m2) 2.00E+02 1.50E+02 1.00E+02 5.00E+01 0.00E+00 0% 20% 40% 60% 80% 100%

Percentage

[211]

FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 Histogram for Co-60 Survey Unit: B308101A

Description:

CRIB HOUSE/FOREBAY STRUCTURAL Mean: 6.12E+01 pCi/m2 Median: 4.37E+01 pCi/m2 ST Dev.: 63.762445 Skew: 0.743206 Frequency Plot For Co-60 10 9

8 7

Frequency 6

5 4

3 2

1 0

3.07E+01 6.14E+01 9.22E+01 1.23E+02 1.54E+02 1.84E+02 Upper End Value (pCi/m2)

Upper Value Observation Observation Frequency %

3.07E+01 6 43%

6.14E+01 3 21%

9.22E+01 0 0%

1.23E+02 2 14%

1.54E+02 2 14%

1.84E+02 1 7%

TOTAL 14

[212]

FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 Histogram for Cs-137 Survey Unit: B308101A

Description:

CRIB HOUSE/FOREBAY STRUCTURAL Mean: 5.82E+01 pCi/m2 Median: 2.49E+01 pCi/m2 ST Dev.: 82.014195 Skew: 1.791894 Frequency Plot For Cs-137 10 9

8 7

Frequency 6

5 4

3 2

1 0

4.63E+01 9.26E+01 1.39E+02 1.85E+02 2.32E+02 2.78E+02 Upper End Value (pCi/m2)

Upper Value Observation Observation Frequency %

4.63E+01 8 57%

9.26E+01 3 21%

1.39E+02 1 7%

1.85E+02 1 7%

2.32E+02 0 0%

2.78E+02 1 7%

TOTAL 14

[213]

FSS RELEASE RECORD CRIB HOUSE / FOREBAY BASEMENT SURVEY UNIT 08100 Retrospective Power Curve for Survey Unit

[214]

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