ML25328A174

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Us Dept of Transportation - Nuclear Ship Savannah, Survey Ship Savannah Survey Unit Release Record Survey Unit STR-207 Health Physics Lab, a Deck
ML25328A174
Person / Time
Site: NS Savannah
Issue date: 11/20/2025
From: Hollenbeck P
US Dept of Transportation, Maritime Admin, Nuclear Ship Support Services
To:
Office of Nuclear Reactor Regulation
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U.S. Department of Transportation Maritime Administration Office of Ship Operations Nuclear Ship Savannah Survey Unit Release Record Survey Unit STR-207 Health Physics Lab, A Deck Senior Technical Advisor Prepared by:

Nuclear Ship Support Services, LLC

SAVANNAH Technical Staff Survey Unit Release Record PREPARED BY /DATE:

PEER REVIEW /DATE:

DECOMMISSIONING PROGRAM MANAGER REVIEW/ DATE:

INDEPENDENT REVIEW/

DATE:

FSS MANAGER REVIEW/ DATE:

LICENSING COMPLIANCE MANAGER REVIEW/ DATE:

SAFETY REVIEW COMMITTEE SUBMITTED/APPROVED Survey Unit STR-207 Health Physics Lab A Deck Pete HO 11 en beck Digitally signed by Pete Hollenbeck Date: 2025.03.20 10:31 :34 -04'00' Pete Hollenbeck, CHP D. Roberson Douglas Roberson Date Digitally signed by D. Roberson Date: 2025.03.2010:14:03 -05'00' Date Soeuth Caleb Soeun DigitallysignedbySoeuthCalebSoeun Date: 2025.0331 07:55:31 -04'00' Soeuth C. Soeun James Reese, CHP, RRPT James Reese Daniel R. Mihalik Daniel Mihalik John Osborne LCM John Osborne 12/10/2024 Submitted Date Digitally signed by James Reese, CHP, RRPT Date: 2025.03.31 07:25:32 -07'00' Date Digitally signed by Daniel R. Mihalik Date: 2025.04.0212:10:19-04'00' Date Digitally signed by: John Osborne LCM DN: CN = John Osborne LCM email

= jmosborne@nsss.llc C = AD Date: 2025.04.07 11 :50:51 -05'00' Date 12/18/2024 Approved Note that this document was re-signed after the review committee comments were resolved.

Page 2 of30

SAVANNAH Technical Staff Survey Unit Release Record TABLE OF CONTENTS

1.

EXECUTIVE Su-MMARY.................................................................................................... 6

2.

SURVEY UNIT DESCRIPTION.......................................................................................... 6

3.

CLASSIFICATION BASIS................................................................................................... 6

4.

DATA QUALITY OBJECTIVES......................................................................................... 7

5.

SURVEY DESIGN............................................................................................................... 10

6.

SURVEY IMPLEMENTATION......................................................................................... 12

7.

SURVEY RESUL TS............................................................................................................. 14

8.

QUALITY CONTROL........................................................................................................ 16

9.

INVESTIGATIONS AND RESULTS................................................................................ 16

10. REMEDIATION AND RES UL TS...................................................................................... 16
11. CHANGES FROM THE FINAL STATUS SURVEY PACKAGE................................. 16
12. DATA QUALITY ASSESSMENT (DQA)......................................................................... 16
13. ANOMALIES........................................................................................................................ 17
14. CONCLUSIONS................................................................................................................... 17
15. REFERENCES..................................................................................................................... 17
16. ATTACHMENTS................................................................................................................. 19 Survey Unit STR-207 Health Physics Lab, A Deck Page 3 of30

SAVANNAH Technical Staff Survey Unit Release Record LIST OF TABLES Table 4 Radionuclide Fractions and Normalized Fractions............................................... 8 Table 4 15 mrem/y DCGLs for ROC and Ni-63.................................................................. 8 Table 4 Re-normalized Co-60 and Cs-137 Fractions.......................................................... 9 Table 4 Operational DCGLs................................................................................................ 10 Table 5 STR-207 Systematic Measurement Designations................................................. 11 Table 5 Scanning Coverage................................................................................................. 12 Table 5 Investigation Levels................................................................................................ 12 Table 7 Summary of Systematic, Judgmental, and QC Static Measurements................ 14 Table 7 Basic Statistical Properties of Static Measurement Population.......................... 15 Table 7 Scan Measurement Summary................................................................................ 15 Survey Unit STR-207 Health Physics Lab, A Deck Page 4 of30

SAVANNAH Technical Staff Survey Unit Release Record LIST OF ACRONYMS AND ABBREVIATIONS ALARA As Low As Reasonably Achievable DQA Data Quality Assessment DQO Data Quality Objective DCGL Derived Concentration Guideline Level FSS Final Status Survey HSA Historical Site Assessment IC Insignificant Dose Contributors LBGR Lower Bound of the Gray Region LTP License Termination Plan MARAD Maritime Administration MARS SIM Multi-Agency Radiation Survey and Site Investigation Manual MDC Minimum Detectable Concentration MDCR Minimal Detectable Count Rate NSS Nuclear Ship Savannah QC Quality Control RASS Remedial Action Support Survey ROC Radionuclides of Concern SOF Sum-of-Fraction TEDE Total Effective Dose Equivalent UBGR Upper Bound of the Gray Region USNRC United States Nuclear Regulatory Commission Survey Unit STR-207 Health Physics Lab, A Deck Page 5 of30

SA VANNAH Technical Staff Survey Unit Release Record

1.

EXECUTIVE

SUMMARY

This Survey Unit Release Record for survey unit STR-207, Health Physics Lab, A Deck, has been generated in accordance with Maritime Administration (MARAD) procedure STS-005-035, Preparation of Survey Unit Release Records and FSS Final Reports [1] and satisfies the requirements of Section 5.10 of the Nuclear Ship SA v ANN AH (NSS) License Termination Plan, STS-004-003 [2].

A Final Status Survey (FSS) survey package for this survey unit was developed in accordance with MARAD procedure STS-005-030, Preparation of Final Status Survey Packages [3], the NSS License Termination Plan, and with guidance from NUREG-1575, Revision 1, Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM)

[4].

This survey unit has a MARS SIM classification of 2. A survey package was designed based upon the use of the Sign Test as the nonparametric statistical test for compliance. Both the Type I (a) and Type II (~) decision error rates were set at 0.05. As a systematic measurement population, fifteen (15) static beta measurements were acquired from the survey unit. In addition, two judgmental static beta measurements were acquired. Surface scanning was performed on approximately 36% of the total surface area in the survey unit.

The data assessment results for survey unit STR-207 show that the maximum gross activity concentration among systematic and judgmental measurements is equal to 874 dpm/100 cm2, which is 1.7% of the operational Derived Concentration Guideline Level (DCGLw) value of 52,300 dpm/100 cm2. Therefore, the null hypothesis of the Sign Test is rejected, and survey unit STR-207 is acceptable for unrestricted release. The mean gross activity concentration among the systematic and judgmental measurements is equal to 684 dpm/100 cm2, which is 1 % of the 15 rnrem/y gross activity DCGLw of 69,700 dpm/100 cm2. The mean gross activity concentration is equal to 0.15 mrem/y for the survey unit.

2.

SURVEY UNIT DESCRIPTION STR-207 is an impacted Class 2 survey unit. The HP Laboratory was utilized primarily as a count room and for processing film badges. Records also indicate that decontamination of equipment was occasionally performed in the Health Physics Counting Lab on A Deck, which required moving packaged radioactive material through clean areas. The survey unit consists of base and wall cabinets, countertop and sink. The deck surface area is approximately 13.83 square meters (13.83 m2), based upon Computer Aided Design drawings. The total surface area including the bulkheads and overhead is 73.51 m2. Refer to Attachment 1 of this report for figures and maps depicting survey unit STR-207.

3.

CLASSIFICATION BASIS Based on the NSS Historical Site Assessment [HSA] [5], survey unit STR-207, identified as survey unit 202Al in the HSA, was identified as a Class 2 structure survey unit. No Survey Unit STR-207 Page 6 of30 Health Physics Lab, A Deck

SAVANNAH Technical Staff Survey Unit Release Record spills or incidents were identified in the HSA. The 2023 Remedial Action Support Survey (RASS), STR-207-RASS-01-Rev O shows the room, including the hot sink, to be at background levels. Based upon review of the historical information, the results of the characterization survey data, and completion of a final Survey Unit Classification Worksheet, the correct final classification of survey unit STR-207 was determined to be Class 2.

4.

DATA QUALITY OBJECTIVES FSS planning and design relies on a properly executed 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 NSS LTP in accordance with MARSSIM. The appropriate design for a given survey was developed using the DQO process as outlined in Appendix D ofMARSSIM.

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 package, 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 STR-207 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).

MARAD Contractor Report CR-139, Calculations to Support NSS Swface Contamination DCGLs [ 6] established the basis for an initial suite of potential Radionuclides of Concern (ROC) for decommissioning. Insignificant dose contributors (IC) were determined consistent with the guidance contained in Section 3.3 of NUREG-1757, Volume 2, Revision 1, Consolidated Decommissioning Guidance - Characterization, Survey, and Determination of Radiological Criteria [7]. In all analyses, Cs-137 and Co-60 contribute nearly 100% of the total dose. The remaining radionuclides were designated as IC. Because Ni-63 comprises approximately 90% of the total activity, it is accounted for as a surrogate to Co-60. Therefore, the final ROCs for final status surveys are Cs-137 and Co-60surrogate, LTP Chapter 6, Section 6.13 discusses the process used to derive the ROC for the decommissioning of the NSS, including the elimination of insignificant dose contributors Survey Unit STR-207 Health Physics Lab, A Deck Page 7 of30

SAVANNAH Technical Staff Survey Unit Release Record from the initial suite. Table 4-1 presents the initial suite of ROC for the decommissioning of the NSS, and the normalized mixture fractions based on the radionuclide mixture.

Table 4-1-Radionuclide Fractions and Normalized Fractions Normalized Sum of Sum of Only Co, Ni Nuclide Fractions Fractions and Cs C-14 3.37E-02 5.61E-03 Co-60 9.78E-02 1.63E-02 1.63E-02 Ni-63 5.40E+00 9.00E-01 9.00E-01 Sr-90 9.22E-06 l.54E-06 Tc-99 l.27E-04 2.llE-05 Ag-108m 8.30E-04 1.38E-04 Cs-137 4.57E-01 7.61E-02 7.61E-02 H-3 l.93E-03 3.21E-04 Fe-55 8.l0E-03 1.35E-03 Am-241 5.79E-07 9.66E-08 Pu-239/240 4.81E-07 8.0lE-08 Totals 6.00E+00 l.00E+00 9.93E-01 Each radionuclide-specific DCGLw 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 15 mrem/yr to an Average Member of the Critical Group. Table 4-2 presents the 15 mrem/y DCGLw for Co-60, Ni-63 and Cs-137 from Chapter 6 of the L TP.

Table 4 15 mrem/y DCGLs for ROC and Ni-63 Radionuclide DCGLw (dpm/100cm2)

Co-60 2.37E+04 Ni-63 2.53E+08 Cs-137 1.20E+05 Nickel-63 is a Hard-to-Detect (HTD) radionuclide. To account for Ni-63, the Easy-To-Detect (ETD) radionuclide Co-60 will be used as a surrogate.

The surrogate DCGL is computed as:

DCGL DCGLETD X DCGLHTD surrogate =

(f HTD:ETvxDCGLETv)+DCGLHTD Equation 1 Where:

DCGLEm = the DCGL for the easy-to-detect radionuclide Survey Unit STR-207 Page 8 of30 Health Physics Lab, A Deck

SAVANNAH Technical Staff Survey Unit Release Record 1 -*¥ *-- +rt DCGLHTo = the DCGL for the hard-to-detect radionuclide FHm:ETD

= the activity ratio of the hard-to-detect radionuclide to the easy-to-detect radionuclide Using the data in Table 4-1, the Ni-63/Co-60 ratio equals 55.3. Solving Equation 1 using the DCGLs for Co-60 and Ni-63 in Table 4-2 and the Ni-63/Co-60 ratio of 55.3 is shown below.

DCGLco-60 surrogate= 2.37E + 04 x C 2

53 E+~a E

= 2.36E+04 dpm/100 cm2 55.3 X 2.37E+04 +2.53 +08 A gross activity DCGLw has been established, based on the representative radionuclide mix, as follows:

Where:

n DCGLn Gross Activity DCGLw =

1 fraction of the total activity contributed by radionuclide n the number of radionuclides

= DCGL for the Radionuclide of Concern (ROC)

Equation 2 Of the three radionuclides, only Co-60 and Cs-13 7 can be detected by gross activity measurements. The normalized fractions for both radionuclides in Table 4-1 have to be re-normalized for use in Equation 2. Table 4-2 presents the re-normalized fractions for each radionuclide.

Table 4-3-Re-normalized Co-60 and Cs-137 Fractions Nuclide C-14 Co-60 Ni-63 Sr-90 Tc-99 Ag-108m Cs-137 H-3 Fe-55 Am-241 Pu-239/240 Totals Survey Unit STR-207 Health Physics Lab, A Deck Normalized sum of fractions 5.61E-03 1.63E-02 9.00E-01 l.54E-06 2.llE-05 l.38E-04 7.61E-02 3.21E-04 1.35E-03 9.66E-08 8.0lE-08 l.00E+00 Only Co-60 Re-and Cs-137 normalized Fractions Fractions l.63E-02 l.76E-01 7.61E-02 8.24E-01 9.24E-02 l.00E+00 Page 9 of30

SAVANNAHTechnical Staff Survey Unit Release Record Solving Equation 2 using the re-normalized Co-60 and Cs-13 7 fractions and the Co-60 surrogate DCGL is shown below.

1 Gross Activity DCGLw = 1_76E-l + s.z4E-l = 6.97E+04 dpm/100 cm2*

2.36E+o4 1.20E+os The DCGLs are reduced to a fraction of the 15 mrem/yr dose limit. The reduced DCGLs, or operational DCGLw, is then used as the DCGL for the FSS design of the survey unit (investigations levels, etc.). The operational DCGLs are set at 75% of the 15 mrem/y DCGLw. The operational DCGLs are provided in Table 4-4.

Table 4 Operational DCGLs Radionuclide Operational DCGLw (dpm/100cm2)

Co-60 l.77E+04 Cs-137 9.00E+04 Gross Activity 5.23E+04 Instrument DQOs included a verification of the ability of the survey instrument to detect the radiation(s) of interest relative to the operational DCGLw. 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 ensure the quality and prevent the loss of data. MARS SIM states that a Minimum Detectable Concentration (MDC) below 10%

of the DCGL is preferable and up to 50% is acceptable. Because the background is low on the NSS, the MDC for most static and scan measurements were less than 10% of the DCGL and in all cases the MDCs were less than 50% of the DCGL.

5.

SURVEY DESIGN The L TP specifies that the Sign Test will be used as the nonparametric statistical test for compliance with the release criteria. The number of measurements for use with the Sign Test was determined in accordance with MARAD procedure STS-005-031, Calculation Of The Number of Measurements For Final Status Surveys. [8] The relative shift (/1/cr) for the survey unit data set is defined as shift (d), which is the Upper Boundary of the Gray Region (UBGR), or the operational DCGLw, minus the Lower Bound of the Gray Region (LBGR),

divided by sigma ( cr), which is the standard deviation of the data set used for survey design.

The optimal value for 11/cr should range between one (1) and three (3). The largest value the 11/cr can have is three (3). If the d/cr exceeds three (3), then the value of two (2) will be used for 11/cr.

A RASS survey was performed on 11/13/23. Forty (40) static measurements and 40 smears were collected. Only 1 smear had positive alpha activity at 2.792 dpm/100 cm2. The Survey Unit STR-207 Page 10 of30 Health Physics Lab, A Deck

SAVANNAH Technical Staff Survey Unit Release Record maximum beta activity was 58.435 dpm/100 cm2. The average activity concentration and standard deviation of the measurements was 851 and 182 dpm/100 cm2, respectively.

Because the activity concentration is low, the LBGR was set to half the operational DCGLw. The relative shift for survey unit STR-207 is based upon the RASS survey results and was calculated as follows:

52,300-26,150 Relative Shift=------= 143.45 182 Because the calculated relative shift was greater than three (3), the value of two (2) was used as the adjusted !::Ja. Both the Type I error, or a value, and the Type II error, or p value, was set at 0.05. The sample size from Table 5.5 of MARS SIM that equates to the Type I and Type II error of 0.05 for use with the Sign Test is an N value of fifteen (15). Fifteen (15) total systematic measurements were used in the survey design for survey unit STR-207.

The survey unit was designated Class 2, therefore the measurement locations were selected based on a systematic grid with a random starting point. The systematic locations of the static measurements were selected using Visual Sample Plan (VSP). Input parameters included the use of survey unit drawings and the systematic sampling tool set with a predetermined number of measurement locations. The systematic measurement locations were identified in the field using dimension parameters provided on the survey unit map (see Attachment 1). Table 5-1 lists the systematic measurements to be collected for FSS of survey unit STR-207.

Table 5 STR-207 Systematic Measurement Designations Label LX(m) LY(m)

LZ(m)

Surface STR-207-01 0.33 1.69 0.00 Deck STR-207-02 2.52 1.69 0.00 Deck STR-207-03 4.72 1.69 0.00 Deck STR-207-04 0.53 0.05 2.74 Overhead STR-207-05 2.73 0.05 2.74 Overhead STR-207-06 4.92 0.05 2.74 Overhead STR-207-07 1.63 1.96 2.74 Overhead STR-207-08 3.83 1.96 2.74 Overhead STR-207-09 2.74 1.27 1.27 Bulkhead 1 STR-207-10 4.94 1.27 1.27 Bulkhead 1 STR-207-11 1.05 1.27 1.27 Bulkhead 2 STR-207-12 0.97 1.27 1.27 Bulkhead 3 STR-207-13 3.17 1.27 1.27 Bulkhead 3 STR-207-14 5.36 1.27 1.27 Bulkhead 3 STR-207-15 1.48 1.27 1.27 Bulkhead 4 The implementation of quality control (QC) measures is referenced in LTP Chapter 5, Section 5.11. A randomly chosen replicate measurement was specified in the survey Survey Unit STR-207 Health Physics Lab, A Deck Page 11 of30

SAVANNAH Technical Staff Survey Unit Release Record package. This measurement was to be collected by either a different technician or by a different instrument. Location STR-207-09 was chosen for the replicate measurement. In addition, the survey package also specified to perform QC operability checks of field instruments both prior to and after collection of the measurements.

The survey package also specified collection of two judgmental measurements to augment the systematic measurements. The locations of these two measurements were to be determined by the technicians and/or the field supervisor. Those two judgmental measurements are identified as STR-207-16-J and STR-207-17-J. Those locations would be documented on the field forms.

For this Class 2 structure survey unit, the "Scanning Coverage" are those levels specified in LTP Chapter 5, Table 5-3, and are reproduced below in Table 5-2.

Table 5 Scanning Coverage Classification Required Scanning Coverage Fraction Class 2 Decks, or lower bulkheads of rooms: 10% to 100%

Uooer bulkheads or overheads: 10% to 50%

For survey unit STR-207, seven scan areas were established. The survey package stated to scan 100% of the accessible area in each scan area SA-01 through SA-07 and scan a 2-foot radius around each static survey location. An estimated 50% of the surface area in STR-207 was to be scanned. Refer to Attachment 1 for figures and maps depicting the measurement and scan locations in survey unit STR-207.

For this Class 2 structure survey unit, the "Investigation Levels" for direct and scanning measurement results are those levels specified in LTP Chapter 5, Table 5-2, and are reproduced below in Table 5-3.

Table 5 Investigation Levels Classification Direct Investigation Levels Scan Investigation Levels Class 2

> Operational DCGLw

> Operational DCGLw These investigation levels were specified in the survey package.

An additional action level was specified in the survey package. If the technician observed a count rate of2,500 cpm when scanning, approximately one-half of the investigation level, they were to stop scanning, backup and rescan the elevated location again to see if the count rate was observed again. If observed again, an additional static measurement would be collected. If not, they would continue scanning.

6.

SURVEY IMPLEMENTATION For survey unit STR-207, compliance with the unrestricted release criteria was demonstrated through a combination of surface scanning and surface static measurements Survey Unit STR-207 Health Physics Lab, A Deck Page 12 of30

SAVANNAH Technical Staff Survey Unit Release Record with a Ludlum Model 43-93 ZnS detector connected to a Ludlum Model 3002 meter operating in the beta mode.

Prior to performing the swvey, a walkdown of the swvey unit was performed per MARAD procedure STS-005-032, Survey Unit Turnover and Control. [9] No conditions prohibited the proper collection of static and scan measurements.

FSS field activities were conducted under the approved FSS Package Number NSS-FSSP-STR-207-00-00, which included DQOs, swvey design, detailed FSS instructions, swvey maps and swvey forms. FSS field activities were projected to take two (2) working days to complete. A daily briefing was conducted to discuss the expectations for job performance and to review safety aspects of the job. An FSS package "Field Log" was used to document field activities and other information pertaining to the performance of the FSS.

The FSS field activities took one day to complete and was performed on April 23, 2024, with the exception of the 2-foot scan around the two judgmental locations. This condition was observed when performing the preliminary data review. On July 10, 2024, the 2-foot scans around the two judgmental locations were performed.

An ambient background count rate was collected by taking a I-minute static measurement, while maintaining the detector waist high. This value was used to calculate the MDC for scanning and static measurements.

The fifteen (15) systematic static measurement locations were marked based on the dimensions provided on the swvey map. Two (2) judgmental measurement locations were selected and marked as per the sample plan. A I -minute static measurement was acquired at each location with the detector in contact with the surface.

All planned scan areas, SA-01 through SA-07, were scanned. A 2-foot radius around each systematic and judgmental static swvey location was also scanned. Approximately 36% of the total surface area was scanned. This is less than the estimated scan area; however, the actual scan area meets the requirements of Class 2. Scanning was performed with the detector held approximately 0.75 inches from the surface while moving at a speed of one detector width per second. No locations were identified during scanning that triggered the 2,500 cpm action level.

The implementation of swvey specific QC measures included the collection of one replicate static measurement. The random location of the replicate measurement was STR-207-09 and identified as STR-207-09-D. That measurement was collected with a different instrument but the same make and model used for all the other measurements.

The instruments used for this swvey were satisfactorily checked prior to and after performing the swvey.

Survey Unit STR-207 Page 13 of30 Health Physics Lab, A Deck

SAVANNAH Technical Staff Survey Unit Release Record

7.

SURVEY RESULTS The efficiencies used to convert count rates to activity are weighted efficiencies in which the Tc-99 (Co-60 surrogate) and Cs-137 efficiencies are weighted by the fraction Co-60 and Cs-137 comprise the NSS fingerprint. This is documented in CR-164 [10]. For example, if the 41t contact Tc-99 efficiency is 0.1002 c/d and the 41t Cs-137 contact efficiency is 0.1868 c/d, the weighted contact efficiency is shown below.

Weighted efficiency (c/d) = (0.1002)(0.176) + (0.1868)(0.824) = 0.1716 c/d Copies of the instrument calibration records are presented in Attachment 2.

The ambient background count rate from a I-minute count was 122 cpm. Rounding up the count rate to 125 cpm, using the contact detector efficiency of 0.1716 c/d and using LTP Equation 5-6, which was derived from NUREG-1507, in which the count time and background count times are equal, results in an MDC for I-minute static measurement equal to 320 dpm/100 cm2. This value is less than 1 % of the operational and gross activity DCGLw. Table 7-1 presents the activity concentration for all static measurements.

Table 7 Summary of Systematic, Judgmental, and QC Static Measurements Activity Concentration Measurement ID (dpm/100 cm2)

STR-207-01 693.64 STR-207-02 868.51 STR-207-03 804.39 STR-207-04 804.39 STR-207-05 734.44 STR-207-06 530.43 STR-207-07 874.34 STR-207-08 781.08 STR-207-09 658.67 STR-207-10 559.58 STR-207-11 641.18 STR-207-12 530.43 STR-207-13 495.46 STR-207-14 786.90 STR-207-15 594.55 STR-207-16-J 612.04 STR-207-17-J 658.67 STR-207-09-D 777.83 The raw static data with detector efficiencies are presented in Attachment 3.

Table 7-2 presents the basic statistical properties of the static measurement population, without the duplicate measurement.,

Survey Unit STR-207 Health Physics Lab, A Deck Page 14 of30

SAVANNAH Technical Staff Survey Unit Release Record Table 7 Basic Statistical Properties of Static Measurement Population Parameter Value Units Minimum Measurement 495.46 dpm/100 cm2 Maximum Measurement 874.34 dpm/100 cm2 Mean 684.04 dpm/100 cm2 Median 658.67 dpm/100 cm2 Standard Deviation 121.55 dpm/100 cm2 Coefficient of Variation 0.18 unitless Residual activity dose rate 0.15 mrem/y The mean activity from static measurements was divided by the gross activity DCGLw to derive a mean fraction. The mean fraction was then multiplied by 15 mrem/yr to derive the dose attributed to the survey unit. For survey unit STR-207, the calculated dose from residual activity is 0.15 mrem/yr.

Calculation of the scan MDC used the same rounded count rate of 125 cpm, the detector efficiency of 0.1081 c/d at a distance of 0.75 inches and using LTP Equation 5-8, which was derived from NUREG-1507. The elevated area was assumed to be a 100 cm2 circular source. The detector width is 3.6 inches, and the detector speed is 3.6 in/second. With these parameters, the resulting observation interval is 1.234 seconds. The resulting MDC for scanning is 1,407 dpm/100 cm2. This value is 3% of the operational DCGLw and 2% of the gross activity DCGLw.

Table 7-3 presents activity concentrations for all scan measurements.

Table 7 Scan Measurement Summary Low to High Range Average Scan ID

( dpm/100 cm2)

(dpm/100 cm2)

SA-01 739.8 - 1294.65 1017.22 SA-02 739.8 - 1109.7 924.75 SA-03 739.8 - 1017.22 878.51 SA-04 832.27 - 1202.17 1017.22 SA-05 647.32 - 1017.22 832.27 SA-06 693.56 - 1063.46 878.51 SA-07 693.56 - 1063.46 878.51 STR-207-01 693.56 - 1155.93 924.74 STR-207-02 1294.65 - 1572.07 1433.36 STR-207-03 924.75 - 1202.17 1063.46 STR-207-04 1063.46 - 1294.65 1179.06 STR-207-05 1109.7 - 1294.65 1202.18 STR-207-06 1109.7 - 1387.12 1248.41 STR-207-07 1109.7 - 1294.65 1202.18 STR-207-08 739.8 - 1017.22 878.51 STR-207-09 832.27 - 1109.7 970.98 STR-207-10 739.8 - 924.75 832.28 Survey Unit STR-207 Page 15 of30 Health Physics Lab, A Deck

SAVANNAH Technical Staff Survey Unit Release Record Scan ID STR-207-11 STR-207-12 STR-207-13 STR-207-14 STR-207-15 STR-207-16-J STR-207-17-J Low to High Range Average (dpm/100 cm2)

(dpm/100 cm2) 832.27 - 1109.7 970.98 739.8 - 1109.7 924.75 832.27 - 1017.22 924.74 924.75 - 1109.7 1017.22 739.8 - 1109.7 924.75 691.78 - 1773.79 1232.78 940.11 - 1560.94 1250.52 The raw scan data with detector efficiencies are presented in Attachment 3.

8.

QUALITY CONTROL The implementation of survey specific QC measures included the collection of one replicate static measurement (STR-207-09-D) for analysis. The acceptance criteria for replicate static measurements is defined by NUREG-1576, MARLAP volume 1, Appendix C, Section C.4.2.2 Duplicate Analyses [11]. That section states that when the average of the two measurements is less than the UBGR, the control limit for the absolute difference between the two values is 4.24µMR.. The value for µMR is equal to the shift divided by 10.

The shift is equal to the operational DCGLw minus one half the operational DCGLw, or 26,150 dpm/100 cm2. Therefore, the control limit is equal to 11,087.6 dpm/100 cm2, as shown below.

Control limit= 26,150/10*4.24 = 11,087.6 dpm/100 cm2.

The results of the evaluation of the quality control measurement shows agreement between the original and duplicate measurements. See Attachment 4 for the results.

9.

INVESTIGATIONS AND RESULTS No investigation levels were triggered, and no investigations were performed as the result of the analysis of the collected data.

10.

REMEDIATION AND RESULTS No radiological remedial action was performed in this survey unit as a result of the FSS.

11.

CHANGES FROM THE FINAL STATUS SURVEY PACKAGE There were no addendums to the FSS package which was developed in accordance with STS-005-030, Preparation of Final Status Survey Packages [3].

12.

DATA QUALITY ASSESSMENT (DQA)

The DQO sample design and data were reviewed in accordance with MARAD procedure STS-005-033, Final Status Survey Data Assessment and Investigation [12] for completeness and consistency. Documentation was complete and legible. Scan surveys and Survey Unit STR-207 Health Physics Lab, A Deck Page 16 of30

SAVANNAH Technical Staff Survey Unit Release Record f -. --- hat the collection of static measurements were consistent with the DQOs and were sufficient to ensure that the survey unit was properly designated as Class 2.

The preliminary data review consisted of calculating basic statistical quantities ( e.g., mean, median, standard deviation). The mean and median values of the data were well below the operational DCGLw. The survey unit data is presented graphically in a frequency plot and quantile plot presented in Attachment 6.

Although MARSSIM states that the Sign Test need not be performed in the instance that no measurements exceed the DCGL, the test was conducted to demonstrate coherence to the statistical principles of the DQO process. The Sign Test 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 results of the Sign Test are presented in Attachment 5.

13.

ANOMALIES No anomalies were observed during the performance of the survey.

14.

CONCLUSIONS Survey unit STR-207 has met the DQOs of the FSS package. The survey unit is properly classified as Class 2.

The sample data passed the Sign Test. The null hypothesis was rejected. Therefore, the survey unit meets the release criteria.

The dose contribution from residual activity in survey unit STR-207 is 0.15 mrem/yr TEDE, based on the mean activity of measurements used for non-parametric statistical sampling.

Survey unit STR-207 is acceptable for unrestricted release.

15.

REFERENCES

[1] "STS-005-035, Preparation of Survey Unit Release Records and FSS Final Reports".

[2] "STS-004-003, N.S. Savannah License Termination Plan".

[3] "STS-005-030, Preparation of Final Status Survey Packages".

[4] "NUREG-1575, Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM), Revision 1, August 2000".

[5] "CR-003, STS-109, Historical Site Assessment, 2008".

Survey Unit STR-207 Health Physics Lab, A Deck Page 17 of30

SAVANNAH Technical Staff Survey Unit Release Record

[6] "CR-139, TSD 21-089, Calculations to Support NSS Surface Contamination DCGLs, Rev 01, September 2022".

[7] "NUREG-1757, Vol 2, Rev 1, Characterization, Survey, and Determination of Radiological Criteria".

[8] "STS-005-031, Calculation of The Number of Measurements For Final Status Surveys".

[9] "STS-005-032, Survey Unit Turnover and Control".

[10] "CR-164, TSD 23-126, "Calculation of Weighted Efficiencies and MDCs of Ludlum Detectors for Final Status Surveys on the NS Savannah", Rev 01 ".

[11] "NUREG-1576, Multi-Agency Radiological Laboratory Analytical Protocols Manual, MARLAP, July 2004".

[12] "STS-005-033, Final Status Survey Data Assessment and Investigation".

Survey Unit STR-207 Page 18 of30 Health Physics Lab, A Deck

SAVANNAH Technical Staff Survey Unit Release Record

16.

ATTACHMENTS - Figures and Maps - Calibration Records - Static and Scan Data - Quality Control Assessment - Sign Test - Graphical Presentations Survey Unit STR-207 Health Physics Lab, A Deck Page 19 of30

SA VANNA/, Technical Staff Survey Unit Release Record Survey Unit STR-207 Health Physics Lab, A Deck - Figures and Maps Location of the Health Physics Lab, A Deck l

A-15 A-13 A-II A-9 A-1 A-5 A-I r

HJ BOW tr Page 20 of30

S A YANNAII Technical Staff Survey Unit Release Record j

Health Physics Lab Systematic and Judgmental Static Locations STR-207-01 TR-207-I5

'-TR-207-1 I Ink)

-$,STR-207-I4 LEGEND*

V p _ mple e

inPouu Survey Unit STR-207 Health Physics Lab, A Deck

-Ef,: TR-207-09

,$: TR-207-10

-$ TR-207 -02

-EJ?R-207-03 TR-207-08

~

TR 207-I7.J

-$= TR-207-II (Courcor)

TR-207-04 TR-207-05 STR-207-06 VSP origin point in ship coordinates: A Deck

-$,STR-207-13 TR-207-2 Frame 126 12' 5" Port of Centerline 50' O" ABL (above baseline)

NOTES SAt 1PLE LOCATIONS CREA TED IN VISUALS 1PLE PLAN u, BER OF 's.Al,1PLES 15 PLACEi t T ~IETH D Y TEI.IATIC START LOC. RANDO~ 1 BOW D Page 21 of30

SAVANNA/I Technical Staff Survey Unit Release Record SA-06 Survey Unit STR-207 Health Physics Lab, A Deck SA-02 f --jf -- -- 'l rt Health Physics Lab Scan Areas SA-03 SA-01 SA-04 SA-07 SA-05 BOW D Page22 of30

S1vANNA11 Technical Staff Survey Unit Release Record - Calibration Records C Jlbratlo,. Ce'11ti ID Numi;Mtr, 25035132000 20240)0 - 1 C RSCS 11r; R

& Co, I ol s.tv,

, Inc Road N 0387'!

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\\ j Survey Unit STR-207 Page23 of30 Health Physics Lab, A Deck

_ _J

S1 v AJVNAJJ Technical Staff Survey Unit Release Record l - ---

Ca ibration Cfftificate - ID N mber. 25035147000 - 20240304 - 1 RSCS Customer: ~ch;,,~ G i-iuntrer Rad1a on Sa';;t/ & Cor-irol Seiv s Inc 93 ledge oad lnstru~nl Ludlum odel ? -~

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i j Survey Unit STR-207 Page24 of 30 Health Physics Lab, A Deck

SAVANNAH Technical Staff Survey Unit Release Record Meter ID 25035147 25035147 25035147 25035147 25035147 25035147 25035147 25035147 25035147 25035147 25035147 25035147 25035147 25035147 25035147 25035147 25035147 25035132 Survey Unit STR-207 Health Physics Lab, A Deck 1 -- -- d:

1 rt - Static Data Count Rate Total Weighted Eff Measurement ID (cpm)

(c/d)

STR-207-01 119 0.1716 STR-207-02 149 0.1716 STR-207-03 138 0.1716 STR-207-04 138 0.1716 STR-207-05 126 0.1716 STR-207-06 91 0.1716 STR-207-07 150

  • 0.1716 STR-207-08 134 0.1716 STR-207-09 113 0.1716 STR-207-10 96 0.1716 STR-207-11 110 0.1716 STR-207-12 91 0.1716 STR-207-13 85 0.1716 STR-207-14 135 0.1716 STR-207-15 102 0.1716 STR-207-16-J 105 0.1716 STR-207-17-J 113 0.1716 STR-207-09-D 119 0.1530 Page 25 of30

SAVANNAH Technical Staff Survey Unit Release Record - Scan Data Meter ID Location 25035147 SA-01 25035147 SA-02 25035147 SA-03 25035147 SA-04 25035147 SA-05 25035147 SA-06 25035147 SA-07 25035147 STR-207-01 25035147 STR-207-02 25035147 STR-207-03 25035147 STR-207-04 25035147 STR-207-05 25035147 STR-207-06 25035147 STR-207-07 25035147 STR-207-08 25035147 STR-207-09 25035147 STR-207-10 25035147 STR-207-11 25035147 STR-207-12 25035147 STR-207-13 25035147 STR-207-14 25035147 STR-207-15 25035132 STR-207-16-J 25035132 STR-207-17-J Survey Unit STR-207 Health Physics Lab, A Deck Min/Max Range Average

{cpm)

{cpm) 80/140 110 80/120 100 80/110 95 90/130 110 70/110 90 75/115 95 75/115 96 75/125 100 140/170 155 100/130 115 115/140 128 120/140 130 120/150 135 120/140 130 80/110 95 90/120 105 80/100 90 90/120 105 80/120 100 90/110 100 100/120 110 80/120 100 78/200 139 106/176 141 1

- d t

Total Weighted eff

{c/d) 0.1081 0.1081 0.1081 0.1081 0.1081 0.1081 0.1081 0.1081 0.1081 0.1081 0.1081 0.1081 0.1081 0.1081 0.1081 0.1081 0.1081 0.1081 0.1081 0.1081 0.1081 0.1081 0.1127 0.1127 Page 26 of30

SAVANNAHTecbnical Staff Survey Unit Release Record 1 - - -- As h Yi - Quality Control Assessment Measurement Value (dpm/100 cm2}

Initial measurement 658.67 Replicate measurement 777.83 Average 718.25 Absolute Value of the difference 119.16 Condition Absolute value of the Control Limit (dpm/100 cm2) difference (dpm/100 cm2)

Result Average < 52,300 119.1 11087.6 Pass Survey Unit STR-207 Page 27 of30 Health Physics Lab, A Deck

SAVANNAH Technical Staff Survey Unit Release Record - Sign Test Measurement Result ID (dpm/100 cm2)

STR-207-01 693.64 STR-207-02 868.51 STR-207-03 804.39 STR-207-04 804.39 STR-207-05 734.44 STR-207-06 530.43 STR-207-07 874.34 STR-207-08 781.08 STR-207-09 658.67 STR-207-10 559.58 STR-207-11 641.18 STR-207-12 530.43 STR-207-13 495.46 STR-207-14 786.90 STR-207-15 594.55 STR-207-16-J 612.04 STR-207-17-J 658.67 Parameter Survey Unit STR-207 Health Physics Lab, A Deck Number of Measurements NumberofS+

Critical Value Meets I Doesn't Meet Acceptance Criteria DCGLw - Result (dpm/100 cm2) 69006.36 68831.49 68895.61 68895.61 68965.56 69169.57 68825.66 68918.92 69041.33 69140.42 69058.82 69169.57 69204.54 68913.10 69105.45 69087.96 69041.33 Result 17 17 12 Meets Sign

+1

+1

+1

+1

+1

+1

+1

+1

+1

+1

+1

+1

+1

+1

+1

+1

+1 Page 28 of30

SAVANNAH Technical Staff Survey Unit Release Record - Graphical Presentations Quantile Plot of Gross Activity Concentration 1000 900 N

800 8

C) 0 0......

700 8

.g.

C) 600 s::=

0 u

C) 500 *

<i::

400 300 0%

10%

20%

30%

40%

50%

60%

70%

80%

Survey Unit STR-207 Health Physics Lab, A Deck 90%

100%

Page 29 of30

SAVANNAHTechnical Staff Survey Unit Release Record Histogram Survey Unit Number: STR-207 Survey Unit Name: Health Physics Lab 4.5 4

3.5 3

>. g 2.5 Q)

J:

2 1.5 0.5 0

543 590 638 685 732 780 Upper end value (dpm/100 cm2)

Survey Unit STR-207 Health Physics Lab, A Deck 827 874 Page 30 of30

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