ML25328A177

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Us Dept of Transportation - Nuclear Ship Savannah, Survey Unit Release Record Survey Unit STR-108 Starboard Charging Pump Room
ML25328A177
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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Download: ML25328A177 (0)
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Text

Approved:

U.S. Department of Transportation Maritime Administration Office of Ship Operations Nuclear Ship Savannah Survey Unit Release Record Survey Unit STR-108 Starboard Charging Pump Room 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-108 Pete Hollenbeck Pete Hollenbeck, CHP D. Roberson Doug Roberson Digitally signed by Pete Hollenbeck Date: 2025.04.21 11 :06:32 -04'00' Date Digitally signed by D. Roberson

---0.ite* 2025 04 21 10*01 *32 -05'00' Date Digitally signed by Soeuth Caleb Soeuth Caleb Soeun Soeun Soeuth C. Soeun James Reese, CHP, RRPT James Reese Date: 2025.04.23 08:33:55 -04'00' Date Digitally signed by James Reese, CHP, RRPT Date: 2025.04.23 11 :35:11

-Q7'QQ' Date Da n *, e I R M *,ha 1

  • , k Digitally signed by Daniel R. Mihalik Date: 2025.04.24 08:48:41 -04'00' Daniel Mihalik Date JO h n Osborne ~~~ally signed by: John Osborne ON: CN = John Osborne LCM email LCM

= jrnosborne@nsss.llc C = AD Date: 2025.05.13 11 :34:19 -05'00' John Osborne Date 4/24/2025 5/2/2025 Submitted Approved Page2 of32 Starboard Charging Pump Room - Hold Deck

SAVANNAH Technical Staff Survey Unit Release Record TABLE OF CONTENTS hrl

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......................................................................................... 13

7.

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

8.

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

9.

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

10. REMEDIATION AND RESULTS...................................................................................... 16
11. CHANGES FROM THE FINAL STATUS SURVEY PACKAGE................................. 17
12. DATA QUALITY ASSESSMENT (DQA)......................................................................... 17
13. ANOMALIES........................................................................................................................ 17
14. CONCLUSIONS................................................................................................................... 17
15. REFERENCES..................................................................................................................... 17
16. ATTACHMENTS................................................................................................................. 18 Survey Unit STR-108 Page 3 of32 Starboard Charging Pump Room

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 4-3 -Re-normalized Co-60 and Cs-137 Fractions.......................................................... 9 Table 4 Operational DCGLs................................................................................................ 10 Table 5 STR-108 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 Table 7-4-10/7/24 Scan Measurement Summary................................................................... 16 Survey Unit STR-108 Page4 of32 Starboard Charging Pump Room

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 L TP License Termination Plan MARAD Maritime Administration MARSSIM 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-108 Starboard Charging Pump Room Page 5 of32

SAVANNAH Technical Staff Survey Unit Release Record

1.

EXECUTIVE

SUMMARY

This Survey Unit Release Record for survey unit STR-108, Starboard Charging Pump Room, 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 SAVANNAH (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 (LTP), 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 1. 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 (13) 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 100% of the accessible total surface area in the survey unit.

The data assessment results for survey unit STR-108 show that the maximum gross activity concentration among systematic and judgmental measurements is equal to 1,215.56 dpm/100 cm2, which is 2.3% 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-108 is acceptable for unrestricted release. The mean gross activity concentration among the systematic and judgmental measurements is equal to 699.67 dpm/100 cm2, which is 1.0% of the 15 mrem/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-108 is an impacted Class 1 survey unit located on the Hold Deck. The Charging Pump/Buffer Seal System was used to supply primary system make up water and supply water under high pressure to seal the control rod drive openings in the reactor vessel head.

Based upon Computer Aided Design drawings, the deck surface area is approximately 15.17 square meters ( 15.17m2), The total surface area including the bulkheads and overhead is 71.14 m2. Refer to Attachment I of this report for figures and maps depicting survey unit STR-108.

3.

CLASSIFICATION BASIS Based on the NSS Historical Site Assessment [HSA] [5], survey unit STR-108, identified as survey unit 106Al in the HSA, was identified as a Class 1 structure survey unit. Based Survey Unit STR-108 Page 6 of32 Starboard Charging Pump Room

SAVANNAH Technical Staff Survey Unit Release Record on the Historical Site Assessment, Section 3.2.3, Conditions at the Conclusion ofDefueling and Deactivation, the pump room bilges were decontaminated, washed, vacuumed, and painted. Also, the Historical Site Assessment, Table 1 in Section 4.2 states that the radiation levels were 0.18 mR/hr on the charging pump and loose contamination levels were less than Minimum Detectable Activity (MDC). In 2019, the charging pumps and associated systems were removed. Based upon a review of the historical information, the results of the characterization survey data, the 2024 Remedial Action Support Survey (RASS) STR-108-RASS-01-Rev 0, and the completion of a final Survey Unit Classification Worksheet, the correct final classification of survey unit STR-108 met the requirements of Class 1.

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 L TP in accordance with MARS SIM. The appropriate design for a given survey was developed using the DQO process as outlined in Appendix D of MARS SIM.

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-108 did not exceed the release criteria specified in the L TP and that the potential dose from residual radioactivity is As Low As Reasonably Achievable (ALARA).

MARAD Contractor Report CR-139, Calculations to Support NSS Surface 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-13 7 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, Survey Unit STR-108 Page 7 of32 Starboard Charging Pump Room

SAVANNAH Technical Staff Survey Unit Release Record L TP 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 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 l.63E-02 l.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 l.38E-04 Cs-137 4.57E-01 7.61E-02 7.61E-02 H-3 1.93E-03 3.21E-04 Fe-55 8.lOE-03 l.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-0l 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 l.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:ETDXDCGLETv)+DCGLHTD Equation 1 Survey Unit STR-108 Page 8 of32 Starboard Charging Pump Room

SAVANNAH Technical Staff Survey Unit Release Record.

Where:

DCGLEm = the DCGL for the easy-to-detect radionuclide DCGLttm = the DCGL for the hard-to-detect radionuclide FHTD: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-6O ratio equals 55.3. Solving Equation 1 using the DCGLs for Co-6O and Ni-63 in Table 4-2 and the Ni-63/Co-6O ratio of 55.3 is shown below.

DCG 2.53E+08 2

Lco-60 surrogate= 2.3 7E + 04 X (

)

= 2.36E+O4 dpm/1OO cm 55.3 x 2.37E+04 +2.53E+08 A gross activity DCGLw has been established, based on the representative radionuclide mix, as follows:

Where:

n DCGLn 1

Gross Activity DCGLw =

11 tz tn DCGL1 + DCGL2 +***vcGLn

= 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-6O and Cs-13 7 can be detected by gross activity measurements. The normalized fractions for both radionuclides in Table 4-1 must be re-normalized for use in Equation 2. Table 4-3 presents the re-normalized :fractions for each radionuclide.

Table 4-3 -Re-normalized Co-60 and Cs-137 Fractions Normalized Only Co-60 Re-sum of and Cs-137 normalized Nuclide fractions Fractions Fractions C-14 5.61E-O3 Co-6O l.63E-O2 l.63E-O2 l.76E-O1 Ni-63 9.OOE-O1 Sr-9O 1.54E-O6 Tc-99 2.1 lE-O5 Ag-108m 1.38E-O4 Cs-137 7.61E-O2 7.61E-O2 8.24E-O1 H-3 3.21E-O4 Fe-55 l.35E-O3 Am-241 9.66E-O8 Survey Unit STR-108 Page 9 of32 Starboard Charging Pump Room

SAVANNAH Technical Staff Survey Unit Release Record Nuclide Pu-239/240 Totals Normalized sum of fractions 8.0lE-08 1.00E+o0 OnlyCo-60 Re-and Cs-137 normalized Fractions Fractions 9.24E-02 1.00E+00 Solving Equation 2, using the re-normalized Co-60 and Cs-137 fractions and the Co-60 surrogate DCGL, is shown below.

1 Gross Activity DCGLw = 1 _76E-l 8 _24E-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 1.77E+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 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 (A/cr) for the survey unit data set is defined as shift(~), 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.

Survey Unit STR-108 Page 10 of32 Starboard Charging Pump Room

SAVANNAH Technical Staff Survey Unit Release Record The optimal value for Ncr should range between one (1) and three (3). The largest value the Ncr can have is three (3). If the Ncr exceeds three (3), then the value of two (2) will be used for Ncr.

A RASS survey was performed between 02/05/24 and 02/12/24. Thirty (30) static measurements and 30 smears were collected. No smears had alpha activity greater than the minimum detectable activity. The maximum beta activity was 60.5 dpm/100 cm2. The average total surface activity concentration and standard deviation of the measurements was 664 and 113 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-108 is based upon the RASS survey results and was calculated as follows:

52,300-26,150 Relative Shift=------= 232 113 Because the calculated relative shift was greater than three (3), the value of two (2) was used as the adjusted Ncr. Both the Type I error, or a value, and the Type II error, or~ value, was set at 0.05. The sample size from Table 5.5 of MARSSIM 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-108.

The survey unit was designated Class 1; 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-108.

Table 5 STR-108 Systematic Measurement Designations Label LX(m) LY(m)

Sample Area STR-108-01 1.11 0.55 Deck STR-108-02 3.28 0.55 Deck STR-108-03 0.03 2.43 Deck STR-108-04

  • 2.20 2.43 Deck STR-108-05 1.11 4.31 Deck STR-108-06 0.79 1.58 Overhead STR-108-07 2.96 1.58 Overhead STR-108-08 1.88 3.46 Overhead STR-108-09 0.31 0.89 Bulkhead2 STR-108-10 1.34 0.89 Bulkhead 3 Survey Unit STR-108 Page 11 of32 Starboard Charging Pump Room

SAVANNAH Technical Staff Survey Unit Release Record Label STR-108-11 STR-108-12 STR-108-13 STR-108-14 STR-108-15 LX(m) LY(m)

Sample Area 1.22 0.89 Bulkhead4 3.39 0.89 Bulkhead 4 1.99 0.89 Bulkhead 5 0.34 0.89 Bulkhead 6 2.51 0.89 Bulkhead 6 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 package. This measurement was to be collected by either a different technician or by a different instrument. Location STR-108-01 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-108-16-J and STR-108-17-J. Those locations would be documented on the field forms.

For this Class 1 structure survey unit, the "Scanning Coverage" are those levels specified in L TP Chapter 5, Table 5-3, and are reproduced below in Table 5-2.

Table 5 Scanning Coverage Classification Required Scanning Coverage Fraction Class 1 100%

For survey unit STR-108, eight scan areas were established, SA-01 through SA-08. The survey package stated to scan 100% of the accessible area in each scan area. Refer to for figures and maps depicting the measurement and scan locations in survey unit STR-108.

For this Class 1 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 Survey Unit Fixed Measurements Scan Measurements Classification Class 1

> Operational DCGLw > Operational DCGLw and an outlier*

These investigation levels were specified in the survey package.

Survey Unit STR-108 Page 12 of32 Starboard Charging Pump Room

SAVANNAH Technical Staff Survey Unit Release Record 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-108, compliance with the unrestricted release criteria was demonstrated through a combination of surface scanning and surface static measurements with a Ludlum Model 43-93 ZnS detector connected to a Ludlum Model 3002 meter operating in the beta mode.

Prior to performing the survey, a walkdown of the survey unit was performed as 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-108-00-00, which included DQOs, survey design, detailed FSS instructions, survey maps and survey forms. FSS field activities were projected to take four (4) 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 three days to complete and were performed between June 25, 2024 through June 27, 2024.

Ambient background count rates were 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 survey 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 eight planned scan areas, SA-01 through SA-08, were scanned, resulting in 100% of the total surface area being scanned. The total scan area meets the scan coverage requirements for a Class 1 area as shown in LTP Table 5-3 and reproduced in Table 5-2 of this release record. 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.

The implementation of survey specific QC measures included the collection of one replicate static measurement. The random location of the replicate measurement was STR-108-01 and identified as STR-108-01-D. That measurement was collected with a different instrument but the same make and model used for all the other measurements.

Survey Unit STR-108 Page 13 of32 Starboard Charging Pump Room

SAVANNAH Technical Staff Survey Unit Release Record The instruments used for this survey were satisfactorily checked prior to and after performing the survey.

7.

SURVEYRESULTS 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 highest ambient background count rate from a !-minute count was 106 cpm and was rounded up to 125 cpm. The contact detector weighted efficiency for a painted surface is equal to 0.0858 c/d. 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 a 1-minute static measurement equal to 641.4 dpm/100 cm2. That value is 1.2% of the operational DCGLw and 0.9% of the 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-108-01 652.99 STR-108-02 652.99 STR-108-03 954.37 STR-108-04 612.81 STR-108-05 642.94 STR-108-06 723.31 STR-108-07 1215.56 STR-108-08 783.59 STR-108-09 401.84 STR-108-10 552.53 STR-108-11 743.40 STR-108-12 642.94 STR-108-13 652.99 STR-108-14 743.40 STR-108-15 803.68 STR-108-16-J 532.44 STR-108-17-J 582.67 STR-108-01-D 1410.98 The raw static data with detector efficiencies are presented in Attachment 3.

Survey Unit STR-108 Page 14 of32 Starboard Charging Pump Room

SAVANNAH Technical Staff Survey Unit Release Record Table 7-2 presents the basic statistical properties of the static measurement population, without the duplicate measurement.

Table 7 Basic Statistical Properties of Static Measurement Population Parameter Value Units Minimum Measurement 401.84 dpm/100 cm2 Maximum Measurement 1215.56 dpm/100 cm2 Mean 699.67 dpm/100 cm2 Median 652.99 dpm/100 cm2 Standard Deviation 181.28 dpm/100 cm2 Coefficient of Variation 0.26 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-108, the calculated dose from residual activity is 0.15 mrem/yr.

Calculation of the scan MDC for the Ludlum 43-93 detector used the highest rounded background count rate of 125 cpm, a distance of 0.75 inches, and the painted surface detector weighted efficiency of 0.0632 c/d. 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 painted surfaces is 2,407.7 dpm/100 cm2.

That value is 4.6% of the operational DCGLw and 3.5% 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-01 450.27 - 2138.80 1294.54 SA-02 520.63 - 1097.54 809.08 SA-03 548.77 - 830.19 689.48 SA-04 464.34 - 858.33 661.34 SA-05 534.70 - 1125.68 830.19 SA-06 576.91 - 1153.82 865.36 SA-07 647.27 - 1041.26 844.26 SA-08 1364.89 - 3531.83 2448.36 The raw scan data with detector efficiencies are presented in Attachment 3.

In the summer of 2024, MARAD and Nuclear Ship Support Services (NSSS) management decided to remove several system components rather than survey them. On September 23 and September 24, 2024, the Intermediate Cooling Water system piping was removed in the Starboard Charging Pump Room. FSS management decided to re-scan the entire room.

Survey Unit STR-108 Page 15 of32 Starboard Charging Pump Room

SAVANNAH Technical Staff Survey Unit Release Record On October 7, 2024, all eight scan areas were re-scanned. Table 7-4 presents the activity concentrations for all scan measurements.

Table 7-4-10/7/24 Scan Measurement Summary Low to High Range Average Scan ID

( dpm/100 cm2)

(dpm/100 cm2)

SA-01 844.26 - 2532.77 1688.51 SA-02 1027.31 - 1867.84 1447.57 SA-03 1369.75 - 1587.66 1478.71 SA-04 1598.05 - 3075.81 2336.93 SA-05 844.26 - 2462.42 1653.34 SA-06 1494.95 - 3161.73 2328.34 SA-07 1546.50 - 3110.18 2328.34 SA-08 1058.44 - 2646.10 1852.27 The raw scan data with detector efficiencies are presented in Attachment 3. No action levels were triggered during the performance of the scan surveys.

8.

QUALITY CONTROL The implementation of survey specific QC measures included the collection of one replicate static measurement (STR-108-01-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 dprn/100 cm2. Therefore, the control limit is equal to 11,087.6 dprn/100 cm2, as shown below.

Control limit= 26,150/10*4.24 = 11,087.6 dprn/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.

Survey Unit STR-108 Page 16 of 32 Starboard Charging Pump Room

SAVANNAH Technical Staff Survey Unit Release Record

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 the collection of static measurements were consistent with the DQOs and were sufficient to ensure that the survey unit was properly designated as Class 1.

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-108 has met the DQOs of the FSS package. The survey unit is properly classified as Class 1.

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-108 is 0.15 mrem/yr TEDE, based on the mean activity of measurements used for non-parametric statistical sampling.

Survey unit STR-108 is acceptable for unrestricted release.

15.

REFERENCES

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

Survey Unit STR-108 Page 17 of32 Starboard Charging Pump Room

SAVANNAH Technical Staff Survey Unit Release Record

[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 (MARS SIM), Revision 1, August 2000".

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

[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 0 1 ".

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

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

16.

ATTACHMENTS - Figures and Maps - Calibration Records - Static and Scan Data - Quality Control Assessment - Sign Test - Graphical Presentations Survey Unit STR-108 Starboard Charging Pump Room Page 18 of32

SAVANNAJt Technical Staff Survey Unit Release Record - Figures and Maps Location of the Starboard Charging Pump Room, Hold Deck I

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hrl Survey Unit STR-108 Page 19 of 32 Starboard Charging Pump Room

SA VANNAtt Technical Staff Survey Unit Release Record Starboard Charging Pump Room Systematic and Judgmental Static Locations B

Bui he, Survey Unit STR-108 Starboard Charging Pump Room 8 1 'lead 3 I

I S

- 108-05 I

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Deck

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TR-108-01 1

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TR-108-3 he d5 STR-1 8-

  • ertlead BL. head4 TR-1 8- :!

VSP origin point in ship coordinates: Hold Deck Frame 126 38' 8" Starboard of Centerline 5' O" Above Baseline NOTES*

SA'APLE LOCA O ~S CREATED

/ISUAl SA,IPLE PLAN NUMBER OF SAMPLES 15 P

CEMENT ilETliOO SYSTEMA C START LOC; RA DOM BOW b Page 20 of32

SAVA NNA /I Technical Staff Survey Unit Release Record SA-07 Bultheed8 Survey Unit STR-108 Starboard Charging Pump Room Starboard Charging Pump Room Scan Areas SA-02 IMldtNd 1 I

SA-04 1Mcheed3 SA-01 Dede I

I SA-03 BtMl.-d2 SA-OS aM!eed-4 SA-08 01191hNd BOW h Page 21 of32

S-1 VANNAJJ Technical Staff Survey Unit Release Record f -if --- - Calibration Records Calibration CtnI11e.1te

  • ID Number: 250351 12000
  • 20240606

customer: Scott (:,,n1eI R.Kl*JltOn SJ!e, & eon JOI 93 ledg: Road Seabrool> NH 03874 Instrument LUdlum ~

  • I 3002 Probe MO<MI LUdlum 43-93 Stnal Number 25035112 serial Number 421417 Precision Check Tesll I

Test2 I

Test3 I

r.1ean I

Results 5.00 kcpm I

4.99 kcpm 1

4.99 kcpm I

4.99 kcpm I

Pass Accuracy Check RaOOP Ti'm..t Val!x>

As Found AS let!

Source 10 AUTO 500 Kcpm =

500Kcpmil 500 Kcpm ii Pulser 98756 AUTO 50 Kcpm "

50Kcpm#

50 Kcpm*

Pulser 98756 AUTO 5 Kcpmw 5 Kcpm#

5Kcpml/

Pulser 98756 AUTO 05Kcpm :

0 499Kcpm ;:

0 d99 Kcpm II Pulser 987'>6 ReaaIngs wltn

  • ln<l ca:e ranges wnere As-Founa reaaIngs are... 20'!1, 01 Target va!Ue RP;id,ngs with ** InaIca*e As-1£,ff re.id ngs are > I()'\\(, or Ta'llf'I valuP Rea<lings w1tn "' riaIcate ra~ were cahbra!ed using a pulser Probe lsoto 43-93 -12 IJ I 7 CS-137(Betal 43-'13 421-1 17 Tc-99 d3-93 J2 IJ 17 Tc-99 93 -1214 17 CS-1371Beta 43-93 ~214 7 Cs 137(Bcta 43-93 4214 17 Tc-99 43-934214 7 Tt-99 41-93 421417 Cs I 37_1B ta)

Ugh Chee Probes Pass Outer Pnysk:31 Llled Pass T, p Tes P~~~

AUOIO Function Chea Pass Cora ctlCC.k P,bS llbra:10n Da!e Sel Pass Cornm,*nls Elf<e' noes Customer Equ pmen ID Cilllbra:e<1 B COie WedHJ Efficiency NIST Source ID 0 1901 CID (4 Pl) 127357 Cs-I37t8etl l 0 1028 CID (4 Pl) 127356 Tc-99 0 0699 CID (4 Pt) 1273"6 Tc-"9 0,360 CID (4 Pl) 1 7357 Cs-137tBel.l l 00167 C/0 (4 Pl 127357 Cs 137*Betal 0 0076 CJD 14 Pl) 127356 Tc-99 0 0056 C/0 (4 Pl) 127356 TC-9:l 0 0152 CID (4 Pl) 127357 Cs I371B till Electronics Checks sec QC Review B Ma Hunter 2~

L o'hg Geome1ry Comment Flat surtace On Contact riat Surface On Con ct FL11 Surf.1 Y 4" /JJ>oVe Source F tSUrlace 314* Al>Ove source Flat Surface OnGra*

Flat surtace OnGra:e F1a1 surta 3/4" AbOV te F ~I Surf,1ce 3/4" PlJ()V Grill As Found As left 70-1 VOits 704 VOits Dale Jun 06. 2024 Expires* Jun 06. 2025 oc Date Jun 06, 2024 lIm*r "'-thOO~ICbOf'lb/I

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    • RSCS R3dgt,on Pr cuon Prog-;un u;,J and I 2 b rf Survey Umt STR-108 Page 22 of32 Starboard Charging Pump Room

S,i v ANNAJJ Technical Staff Survey Unit Release Record if --- h rl

  • Rs C 5 1

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0 AU10 AUTO 43-034 1410 4:l

.,,.. 0 Survey Unit STR-108 Starboard Charging Pump Room I struml.'ffl lud Jill ~I 3002 Pro l'l o46 CID I PIJ 0 Q,471 C/0 [4 P1]

0 OHi$ C/0 ( P1J 0 16. C/0 (' f'I) 7 C.IO (4 "')

0 1, 7 C"..O (4 P1J 0 05J7 CID (4 Pi)

/\\ Found SOO K 49 ~Kcpm#

5 Kc:pm #

1:.>73 2735 12 Tc.

2/3!,

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314 Abcve Grate Page 24 of32

S 1vANNA11 Technical Staff Survey Unit Release Record C ibr lion Ccrtm 1

  • 10 Number 25035132000 2024030. 1 RSCS Customer.

Tc I 5.00 kc m AUTO AUTO lnstrum~nt

, Inc LudIum MOP JOO Pro II el Ludll.,_ 3 Accuracy Check Foui d

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489 Kc:prn 11 Eff,clent 0 o;>,43 CIO (4 P 27 0

5 CIO l~ Pl) 1273~7 0 Ol CID("

)

12/35'7 00177 CID (-4 P J I.'

0 1 ?O C'O {4 P,t 127357 0 110800(4

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?7357 Serial Number 25035132 e al Nu 421425 Resul'.s p

fr

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Survey Umt STR-108 Page 25 of32 Starboard Charging Pump Room

SAVANNAHTechnical Staff Survey Unit Release Record Meter ID 25035112 25035112 25035112 25035112 25035112 25035112 25035112 25035112 25035112 25035112 25035112 25035112 25035112 25035112 25035112 25035112 25035112 25035132 l - - -- d 1 Yi - Static Data Count Rate Total Weighted Eff Measurement ID (cpm)

(c/d)

STR-108-01 65 0.0995 STR-108-02 65 0.0995 STR-108-03 95 0.0995 STR-108-04 61 0.0995 STR-108-05 64 0.0995 STR-108-06 72 0.0995 STR-108-07 121 0.0995 STR-108-08 78 0.0995 STR-108-09 40 0.0995 STR-108-10 55 0.0995 STR-108-11 74 0.0995 STR-108-12 64 0.0995 STR-108-13 65 0.0995 STR-108-14 74 0.0995 STR-108-15 80 0.0995 STR-108-16-J 53 0.0995 STR-108-17-J 58 0.0995 STR-108-01-D 121 0.0858 Note: Meter IDs 25035112 and 25035132 are connected to a Ludlum model 43-93 detector with an area of 100 cm2.

Survey Unit STR-108 Page 26 of32 Starboard Charging Pump Room

SAVANNAH Technical Staff Survey Unit Release Record - Scan Data (6/25/24 and 6/26/24)

Total Min/Max Range Average Weighted eff Date Meter ID Location (cpm)

(cpm)

(c/d) 6/25/2024 25035112 SA-01 80/93 86.5 0.0711 6/25/2024 25035112 SA-02 37/78 57.5 0.0711 6/25/2024 25035112 SA-03 39/59 49.0 0.0711 6/25/2024 25035112 SA-04 33/61 47.0 0.0711 6/25/2024 25035112 SA-05 38/80 59.0 0.0711 6/25/2024 25035112 SA-06 41/82 61.5 0.0711 6/25/2024 25035112 SA-07 46/74 60.0 0.0711 6/25/2024 25035112 SA-08 97/251 174.0 0.0711 6/26/2024 25035112 SA-01 32/152 92.0 0.0711 Note: Meter ID 25035112 is connected to a Ludlum model 43-93 detector with an area of 100 cm2.

Survey Unit STR-108 Page 27 of32 Starboard Charging Pump Room

SAVANNAH Technical Staff Survey Unit Release Record Meter ID 25035112 25017651 25017651 25035102 25035112 25035102 25035102 25017651 - Scan Data (10/7/24)

Min/Max Range Average Location (cpm)

(cpm)

SA-01 60/180 120.0 SA-02 66/120 93.0 SA-03 88/102 95.0 SA-04 93/179 136.0 SA-05 60/175 117.5 SA-06 87/184 135.5 SA-07 90/181 135.5 SA-08 68/170 119.0 Total Weighted eff (c/d) 0.0711 0.0642 0.0642 0.0582 0.0711 0.0582 0.0582 0.0642 Note: Meter IDs 25035112, 25017651 and 25035102 are connected to a Ludlum model 43-93 detector with an area of 100 cm2.

Survey Unit STR-108 Page 28 of32 Starboard Charging Pump Room

SAVANNAH Technical Staff Survey Unit Release Record - Quality Control Assessment Measurement Value (dpm/100 cm2)

Initial measurement 652.99 Replicate measurement 1410.98 Average 1031.985 Absolute Value of the difference 757.99 Condition Absolute value of the Control Limit (dpm/100 cm2) difference (dpm/100 cm2)

Average< 52,300 757.99 11087.6 Survey Unit STR-108 Starboard Charging Pump Room Result Pass Page 29 of32

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

(dpm/100 cm2)

STR-108-01 652.99 69047.01 STR-108-02 652.99 69047.01 STR-108-03 954.37 68745.63 STR-108-04 612.81 69087.19 STR-108-05 642.94 69057.06 STR-108-06 723.31 68976.69 STR-108-07 1215.56 68484.44 STR-108-08 783.59 68916.41 STR-108-09 401.84 69298.16 STR-108-10 552.53 69147.47 STR-108-11 743.40 68956.60 STR-108-12 642.94 69057.06 STR-108-13 652.99 69047.01 STR-108-14 743.40 68956.60 STR-108-15 803.68 68896.32 STR-108-16-J 532.44 69167.56 STR-108-17-J 582.67 69117.33 Parameter Result Number of Measurements 17 Number ofS+

17 Critical Value 12 Meets I Doesn't Meet Acceptance Criteria Meets Survey Unit STR-108 Starboard Charging Pu.mp Room

) -- -- rt J rt Sign

+1

+1

+1

+1

+1

+1

+1

+1

+1

+1

+1

+1

+1

+1

+1

+1

+1 Page 30 of32

SAVANNAHTechnical Staff Survey Unit Release Record - Graphical Presentations Quantile Plot of Gross Activity Concentration 1400 1200 N 5 1000 0

0.-

800 8

0...

'O 600

(.)

i::

0 u 400

+-'

(.)

<t:

200 0

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Note: Gaps between data points are due to measurements with the same value. See Table 7-1.

Survey Unit STR-108 Page 31 of32 Starboard Charging Pump Room

SAVANNAH Technical Staff Survey Unit Release Record Histogram Survey Unit Number: STR-108 Survey Unit Name: Starboard Charging Pump Room 7

6 5

2 0

504 605 707 809 910 1012 Upper end value ( dprn/ 100 cm2)

Survey Unit STR-108 Starboard Charging Pump Room l - - -- 4 1 Yi 1114 1216 Page 32 of32

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