ML25328A166
| ML25328A166 | |
| 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 |
| References | |
| Download: ML25328A166 (0) | |
Text
U.S. Department of Transportation Maritime Administration Office of Ship Operations N.S. SAVANNAH FINAL STATUS SURVEY FINAL REPORT Approved:
Date: November 20, 2025 Senior Technical Advisor Prepared by:
Nuclear Ship Support Services, LLC
Final Status Survey Final Report 1 of 5 PREPARED BY I DATE:
PEER REVIEW/ DATE:
DECOMMISSIONING PROGRAM MANAGER REVIEW/ DATE:
INDEPENDENT REVIEW /
DATE:
FSS MANAGER REVIEW/ DATE:
LICENSING and COMPLIANCE MANAGER REVIEW/ DATE:
SAFETY REVIEW COMMITTEE SUBMITTED/APPROVED LICENSE TERMINATION PLAN MANAGER REVIEW/ DATE:
Pete HO 11 en bee k Digitally signed by Pete Hollenbeck Date: 2025.11.18 15:02:01 -05'00' Pete Hollenbeck, CHP Date J h CI Digitally signed by John Q n ementS Clements Date: 2025.11.18 13:31 :44 -07'00' John Clements, CHP Date Soeuth Caleb Soeun DigitallysignedbySoeuthCalebSoeun Date: 2025.11.19 08:23:37 -05'00' Soeuth C. Soeun James Reese, CHP, RRPT James Reese Daniel Mihalik Daniel Mihalik Date Digitally signed by James Reese, CHP, RRPT Date: 2025.11.19 07:27:54 -08'00' Date Digitally signed by Daniel Mihalik Date: 2025.11.19 11:10:16 -05'00' Date JO h n Osborne Digitally signed by John Osborne Date: 2025.11.19 12:16:24 -05'00' John Osborne Date October 1, 2025 October 7, 2025 Submitted Approved Nov 19, 2025 Eric Darois Date Rev. 0 2
Final Status Survey Fin al Report 1 of 5 RECORDOFRE VISIONS Revision Summary of Revisions Final Status Survey Final Report 1 of 5, Rev. 0 Original LIST OF EFFEC TIVEPAGES Page No.
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Final Status Survey Final Report 1 of 5 EXECUTIVE
SUMMARY
The Nuclear Ship Savannah (NSS) Final Status Survey (FSS) program provides the necessary data and evaluation to support a finding that the ship (the licensed site) meets the Nuclear Regulatory Commission (NRC) radiological criterion for unrestricted use, thus permitting termination of the Maritime Administration's (MARAD) NRC operating license. MARAD's FSS program is described in detail in Chapters 5 and 6 of its revised License Termination Plan (L TP). In particular, Chapter 6 addresses the potential end-state condition of NSS, from among three primary disposition alternatives. These are physical destruction through shipbreaking, intentional sinking to form an artificial reef, and preservation for continued public use. MARAD's preferred outcome is preservation. The limiting condition for analysis is ship breaking. In each case, the areas of the ship of greatest concern are the former Radiologically Controlled Areas (RCA) comprising the several levels of the Reactor Compartment (RC),
and the Containment Vessel (CV) which housed the major components of the nuclear steam supply system (note, several of those components were remediated and left in-situ). This FSS Final Report addresses these areas of highest concern. The results demonstrate that they meet the criterion for unrestricted use.
As described in the LTP, MARAD adopted an administrative dose limit of 15 mrem / year that is less than the NRC limit of25 mrem I year. Because MARAD's preferred end-state outcome is preservation, rather than immediate ship breaking, Table 6-28 of the LTP illustrates the effect of decay over the projected seventy (70) year life of the ship post-decommissioning, beginning from 15 mreml. At 70 years, the dose has decayed to 3 mrem. As this report demonstrates, the highest residual activity dose rate inside the RC/CV was calculated to be 2.05 mrem / year. Table 6-28 is reproduced below, with the decay calculation starting at 2.05 mrem.
Table ES-1 Annual Dose Over Time (mrem)
LT 10 y 20y 30y 40y 50 y 60y 70 y 2.05 1.6 1.3 1.0 0.8 0.6 0.5 0.4 The NSS FSS field campaign was executed from April 2024 to January 2025. The campaign included sixty-seven ( 67) survey units, some of which were subdivisions of a base unit. The complete final list of survey units is provided in Table ES-4. Each survey unit has an individual Survey Unit Release Record (SURR). Each FSS Final Report, of which five (5) are planned, will include a tranche ofSURRs. In this first FSS Final Report, there are fifteen (15) SURRs attached. Reports (2) through (4) will contain approximately fifteen (15) SURRs each. The fifth and last report will describe the surveys of the ship's exterior hull envelope, including the normally underwater portions of the hull. Those surveys were performed in 2019, prior to the establishment of the FSS program, when the ship was fully accessible while on drydock.
Tables ES-2 and ES-3 list the fifteen SURRs included in this report, and their residual activity dose rates.
As may be inferred from the earlier paragraphs, the maximum dose rate within the ship areas of greatest concern is 2.05 mrem I year, which is well below MARAD's administrative limit, and less than ten (10) 1 Both Table 6-28 and ES-1 are based on the decay ofCs-137, one of the Radioisotopes of Concern, and the one that dominates over time - see section 6.15 of the revised L TP for more detail.
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Final Status Survey Final Report 1 of 5 percent of the NRC radiological release criterion. All fifteen survey units are acceptable for unrestricted use.
A dedicated Executive Summary may not be repeated in the remaining FSS Final Reports. Instead, the Introduction section of the follow-on reports will contain summary information germane to their included SURRs.
Table ES-2 Survey Units in FSS Final Report 1 of 5 Survey Unit MARSSIM Description of Survey Unit Class STR-101-01 1
Containment Vessel (CV)- 1st Level (Tanktop), Starboard Side STR-101-02 1
Containment Vessel (CV) - 1st Level (Tanktop), Port Side STR-102 1
Containment Vessel (CV)- 2nd Level (Flat)
STR-103 1
Containment Vessel (CV)- 3rd Level (D Deck)
STR-104 1
Containment Vessel (CV)- 4th Level (C Deck)
STR-105-01 1
Reactor Compartment - Lower Level ( 5' - 23 ') Starboard-side Half STR-105-02 1
Reactor Compartment - Lower Level ( 5' - 23 ') Port-side Half STR-105-03 1
Reactor Compartment - Lower Level, Drain Wells STR-108 1
Starboard Charging Pump Room STR-109 1
Auxiliary Access Trunk, C-Deck the Cold Water Chemistry Lab (Port) and Radiation Monitoring Room (Stbd)
STR-207 2
Health Physics Lab STR-301 3
Navigation Bridge Deck - Interior Surfaces SYS-112 Impacted Primary Pressurizing System (PE) including retained portions of System the pressurizer SYS-117-01 Impacted Neutron Shield Tank Retained Walls System SYS-117-02 Impacted Fuel Transfer Tank Retained Walls System Remainder of page intentionally blank.
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Final Status Survey Final Report 1 of 5 Table ES-3 Residual Activity Dose Rates in Each Survey Unit Survey Unit Dose Rate Survey Unit Dose Rate (mrem/yr)
(mrem/yr)
STR-101-01 2.05 STR-108 0.15 STR-101-02 1.12 STR-109 0.10 STR-102 0.88 SYS-112 0.42 STR-103 0.39 SYS-117-0.37 01 STR-104 1.06 SYS-117-1.17 02 STR-105-01 0.12 STR-207 0.15 STR-105-02 0.14 STR-301 0.13 STR-105-03 0.27 Remainder of page intentionally blank.
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Final Status Survey Final Report 1 of 5 Table ES-4 Final List ofNSS FSS Survey Units SURR SURR Title Report Designation Number STR-101-01 Containment Vessel (CV)- 1st Level (Tank.top), Starboard Report 1 of5 Side STR-101-02 Containment Vessel (CV) - 1st Level (Tank.top), Port Side Report 1 of5 STR-102 Containment Vessel (CV)- 2nd Level (Flat)
Report 1 of5 STR-103 Containment Vessel (CV)- 3rd Level (D Deck)
Report 1 of5 STR-104 Containment Vessel (CV)-4th Level (C Deck)
Report 1 of5 STR-105-01 Reactor Compartment - Lower Level ( 5' - 23 ') Starboard-side Report 1 of5 Half STR-105-02 Reactor Compartment - Lower Level ( 5' - 23 ') Port-side Half Report 1 of5 STR-105-03 Reactor Compartment - Lower Level, Drain Wells Report 1 of5 STR-108 Starboard Charging Pump Room Report 1 of5 STR-109 Auxiliary Access Trunk, C-Deck the Cold Water Chemistry Report 1 of5 Lab (Port) and Radiation Monitoring Room (Stbd)
STR-207 Health Physics Lab Report 1 of5 STR-301 Navigation Bridge Deck-Interior Surfaces Report 1 of5 SYS-112 Primary Pressurizing System (PE) including retained portions Report 1 of5 of the pressurizer SYS-117-01 Neutron Shield Tank Retained Walls Report 1 of 5 SYS-117-02 Fuel Transfer Tank Retained Walls Report 1 of5 STR-106 Port Stabilizer Room and Port Booster Pump Room Report2 of5 STR-107 Port Charging Pump Room Report2 of5 STR-110 Gas Absorption Equipment Room / Radiation Sampling Room Report 2 of 5 STR-111 Cupola Inner Wall, A Deck and B Deck Report2 of5 STR-202-01 Reactor Compartment - Dress, Undress, and Decontamination Report 2 of5 Shower STR-205 Starboard Stabilizer Room Report2 of5 STR-206 Engine Room Machinery Space, Hold Through Boat Deck Report 2 of5 STR-208 Horseshoe Area, Hold Deck Report 2 of5 STR-209 Hot Chemistry Lab, D Deck Report2 of5 STR-211 Reactor Compartment-Mid Level, 14' Flat Deck Report2 of5 STR-306 Promenade Deck, Exterior Surfaces Report 2 of5 STR-313 Refrigerator Rooms - Vegetable and Dairy (Port and Starboard Report2 of5 Passageways and Stairwells) 14' Flat STR-316 Cargo Hold No. 4 - C Deck Report2 of5 STR-317 Elevators and Elevator Shafts Report2 of5 SYS-103 Soluble Poison (SP), Retained Tank Report2 of5 Rev. 0 7
Final Status Survey Final Report 1 of 5 Table ES-4 Final List ofNSS FSS Survey Units (continued)
STR-302 Navigation Deck, Exterior Surfaces Report 3 of 5 STR-303 Boat Deck, Interior Surfaces Report 3 of 5 STR-304 Boat Deck, Exterior Surfaces Report 3 of 5 STR-308 A Deck Forward, Exterior Surfaces Report 3 of 5 STR-309 A Deck Aft, Exterior Surfaces Report 3 of5 STR-311 C Deck, Interior Surfaces Report 3 of 5 D Deck: Electronics Workshop, Bulk and Special Stores STR-312 Rooms, Food Freezers and Refrigerators, Machinery Space Report 3 of5 Equipment and Workshop Room, Engineering Stores Room, Spare Parts Storeroom, Passageways (all)
STR-314 Dry Stores (Port) and Steward (Starboard) Outboard of Report 3 of 5 Horseshoe Area STR-315 Cargo Hold No. 3, C Deck Report 3 of5 SYS-102 Emergency Cooling System (DK)
Report 3 of 5 SYS-114-01 PD-TS, Contaminated Water Tank (Starboard)
Report 3 of 5 SYS-114-02 PD-T6, Contaminated Water Tank (Port)
Report 3 of5 SYS-114-03 Reactor Compartment Void Tank Report 3 of 5 SYS-114-04 Fresh Water Shield Tank Report 3 of 5 SYS-118 Decommissioning Heating, Ventilation, and Air Conditioning Report 3 of5 (HVAC)
STR-201 Reactor Compartment - Mid Level, D Deck Report4 of5 STR-202-00 Reactor Compartment - Mid Level, C Deck Report 4 of5 STR-203 Reactor Compartment - Upper Level, B Deck Report4 ofS STR-204 Reactor Compartment - Upper Level, A Deck Report4 of5 STR-210 Cargo Hold No.4 -Tanktop, D Deck and CV Portal Vestibule Report4 ofS STR-305 Promenade Deck - Interior Surfaces Report4 of5 STR-307 A Deck - Interior Surfaces Report 4 of5 STR-310 B Deck - Interior Surfaces Report4 of5 SYS STR-119 Penetrations (system pipe, sleeves and structure)
Report4 of5 SYS-106 Hydrogen Addition System (HA)
Report4 of5 SYS-109 Intermediate Cooling System (CW)
Report 4 of5 SYS-116-01 Main Steam System including retained portions of the port side Report 4 ofS steam generator shell and associated steam drum SYS-116-02 Main Steam System including retained portions of the starboard Report 4 of5 side steam generator shell and associated steam drum Rev. 0 8
Final Status Survey Final Report 1 of 5 Table ES-4 Final List ofNSS FSS Survey Units (continued)
FSS-310A External Hull, Starboard Fore Report 5 of 5 FSS-311A External Hull, Starboard Mid Report 5 of5 FSS-312A External Hull, Starboard Aft Report 5 of5 FSS-313A External Hull, Port Fore Report 5 of 5 FSS-314A External Hull, Port Mid Report 5 of 5 FSS-315A External Hull, Port Aft Report 5 of 5 FSS-316A External Hull, Starboard Above Boot Stripe Report 5 of 5 FSS-317A External Hull, Port Above Boot Stripe Report 5 of 5 FSS-318A External Hull, Rudder Report 5 of5 End of Section Rev. 0 9
Final Status Survey Final Report 1 of 5 TABLE OF CONTENTS 1
FINAL STATUS SURVEY PROGRAM OVERVIEW........................................................ 15 1.1 Survey Planning..................................................................................................................... 15 1.2 Survey Design........................................................................................................................ 16 1.3 Survey Implementation.......................................................................................................... 17 1.4 Radiological Release Criteria................................................................................................ 17 1.5 Calibration Sources and Efficiencies..................................................................................... 20 1.6 Survey Data Assessment........................................................................................................ 21 1.7 Quality Assurance and Quality Control Measures................................................................. 21 1.7.1 Technician Training............................................................................................................... 22 1.7.2 Instrumentation...................................................................................................................... 22 1.7.3 Periodic Surveillance............................................................................................................. 23 2
SHIP AND SURVEYUNITINFORMATION..................................................................... 23 2.1 Ship Description and History................................................................................................. 23 2.2 Survey Unit Descriptions....................................................................................................... 24 2.2.1 STR-101-01 Containment Vessel (CV) - 1st Level (Tanktop), Starboard Side.................... 24 2.2.2 STR-101-02 Containment Vessel (CV)- 1st Level (Tanktop), Port Side............................. 24 2.2.3 STR-102 Containment Vessel (CV) - 2nd Level (Flat)........................................................ 24 2.2.4 STR-103 Containment Vessel (CV) - 3rd Level (D Deck)................................................... 24 2.2.5 STR-104 Containment Vessel (CV) - 4th Level (C Deck)................................................... 25 2.2.6 STR-105-01 Reactor Compartment-Lower Level (5'-23') Starboard Half........................ 25 2.2.7 STR-105-02 Reactor Compartment-Lower Level (5'-23') Port-side Half............................ 25 2.2.8 STR-105-03 Reactor Compartment-Lower Level (5'-23') Drain Wells............................. 25 2.2.9 STR-108 Starboard Charging Pump Room........................................................................... 25 2.2.10 STR-109 Auxiliary Access Trunk, C-Deck, Cold Water Chemistry Lab (Port) and Radiation Monitoring Room (Stbd)....................................................................................................... 25 2.2.11 STR-207 Health Physics Lab................................................................................................. 26 2.2.12 STR-301 Navigation Bridge Deck - interior surfaces............................................................ 26 2.2.13 SYS-112 Primary Pressurizing System (PE) including retained portions of the pressurizer 26 2.2.14 SYS-117-01 Neutron Shield Tank wall located in the CV.................................................... 26 2.2.15 SYS-117-02 Fuel Transfer Tank wall located in the CV....................................................... 26 2.3 Locations on General Arrangement Drawings...................................................................... 27 3
SUMMARY
OF SURVEY RESULTS............................................................................... 30 3.1 Total Measurements Collected in Each Survey Unit............................................................. 30 3.2 Summary of Survey Results.................................................................................................. 32 3.3 Anomalous Data, Elevated Scan Results and Investigations................................................. 33 3.3.1 STR-101-01, Containment Vessel (CV)- 1st Level (Tanktop), Starboard Side................... 33 3.3.2 STR-101-02, Containment Vessel (CV) - 1st Level (Tanktop), Port Side............................ 33 3.3.3 STR-102, Containment Vessel (CV)- 2nd Level (Flat)....................................................... 34 3.3.4 SYS-112, Primary Pressurizing System (PE)........................................................................ 34 3.4 Comparison of Findings with the Release Criteria................................................................ 34 Rev. 0 10
Final Status Survey Final Report 1 of 5 3.5 NRC and Other Independent Verification Findings.............................................................. 35 4
FSS FINAL REPORT
SUMMARY
...................................................................................... 37 5
References.............................................................................................................................. 38 6
ATTACHMENTS.................................................................................................................. 39 6.1 STR-101-01 Containment Vessel (CV)- 1st Level (Tanktop), Starboard Side..................... 39 6.2 STR-101-02 Containment Vessel (CV)- 1st Level (Tanktop), Port Side.............................. 39 6.3 STR-102 Containment Vessel (CV)-2nd Level (Flat).......................................................... 39 6.4 STR-103 Containment Vessel (CV)- 3rd Level (D Deck).................................................... 39 6.5 STR-104 Containment Vessel (CV)- 4th Level (C Deck).................................................... 39 6.6 STR-105-01 Reactor Compartment-Lower Level (5'-23 ') Starboard Half........................ 39 6.7 STR-105-02 Reactor Compartment-Lower Level (5'-23 ') Port-side Half............................ 39 6.8 STR-105-03 Reactor Compartment-Lower Level (5'-23') Drain Wells............................. 39 6.9 STR-108 Starboard Charging Pump Room........................................................................... 39 6.10 STR-109 Auxiliary Access Trunk, C-Deck, The Cold Water Chemistry Lab (Port) and Radiation Monitoring Room (Stbd)....................................................................................... 39 6.11 STR-207 Health Physics Lab................................................................................................. 39 6.12 STR-301 Navigation Bridge Deck-interior surfaces............................................................ 39 6.13 SYS-112 Primary Pressurizing System (PE) including retained portions of the Pressurizer 39 6.14 SYS-117-01 Neutron Shield Tank wall located in the CV.................................................... 39 6.15 SYS-117-02 Fuel Transfer Tank wall located in the CV....................................................... 39 Rev. 0 11
Final Status Survey Final Report 1 of 5 LIST OF TABLES Table 1-1 Traditional Scanning Coverage Requirements...................................................................... 16 Table 1-2 Radionuclide Fractions and Normalized Fractions................................................................ 18 Table 1-3 15 mrem/y DCGLs for ROC and Ni-63................................................................................. 18 Table 1-4 Re-normalized Co-60 and Cs-13 7 Fractions......................................................................... 20 Table 3-1 Summary of Static Measurements......................................................................................... 31 Table 3-2 Summary of Random and Static Measurement Parameters................................................... 32 Table 3-3 Residual Activity Dose Rates in Each Survey Unit............................................................... 34 Rev. 0 12
Figure 2-1 Figure 2-2 Figure 2-3 Figure 2-4 Figure 2-5 Final Status Survey Final Report 1 of 5 LIST OF FIGURES NSS at Pier 13 in 2023...................................................................................................... 23 Inboard Profile.................................................................................................................. 27 STR-301, Navigation Bridge Deck................................................................................... 27 STR-101-01, 101-02, 102, 103, 104 Containment (Historical Drawing)......................... 28 STR-105-01, -02 and -03, Reactor Compartment-Lower Level.................................... 29 Rev. 0 13
ALARA AMCG CAD CR CV DQAP DQO DCGL ERF ETD FSS HTD
!SOCS LBGR LTP MARAD MARSSIM NRC NSS ORISE QA QC RASS RC RCA RSCS ROC RPT SURR TEDE UBGR VSP Final Status Survey Final Report 1 of 5 ABBREVIATIONS AND ACRONYMS As Low As Reasonably Achievable Average Member of the Critical Group Computer-aided Design Contractor Report Containment Vessel Decommissioning Quality Assurance Plan Data Quality Objective Derived Concentration Guideline Level Efficiency Reduction Factor Easy-To-Detect Final Status Survey Hard-to-Detect In Situ Object Counting System Lower Bound of the Gray Region License Termination Plan United States Department of Transportation, Maritime Administration Multi-Agency Radiation Survey and Site Investigation Manual United States Nuclear Regulatory Commission Nuclear Ship SAVANNAH Oak Ridge Institute for Science and Education Quality Assurance Quality Control Remedial Action Support Survey Reactor Compartment Radiologically Controlled Areas Radiation Safety and Control Services, Inc.
Radionuclides of Concern Radiation Protection Technician Survey Unit Release Record Total Effective Dose Equivalent Upper Bound of the Gray Region Visual Sample Plan Rev. 0 14
Final Status Survey Final Report 1 of 5 1 FINAL STATUS SURVEY PROGRAM OVERVIEW MARAD conducts its FSS activities in accordance with the FSS Plan described in Chapter 5 of the LTP and as described in the Decommissioning Quality Assurance Plan (DQAP) (Reference e ). A suite of FSS implementing procedures was developed (see list below), with procedure STS-005-029, Final Status Survey Program (Reference f) establishing the overarching framework for the FSS program. This procedure expands the description of the FSS organization with roles and responsibilities, and establishes requirements and methods for FSS planning, survey design and implementation, data assessment and investigation, remediation (including potential reclassification and resurvey, where and ifrequired), and reporting. The FSS program is conducted within the overall context of the site procedure program, so that activities are subject to, among other things, the DQAP implementing procedures, Work Control Process, Health and Safety Plan, Radiation Protection Plan, etc. The FSS-specific administrative procedures are listed below:
STS-005-029, Final Status Survey Program (Reference/)
STS-005-030, Preparation of FSS Packages (Reference g)
STS-005-031, Calculation of the Number of Measurements (Reference h)
STS-005-032, Survey Unit Turnover and Control (Reference i)
STS-005-033, Final Status Survey Data Assessment (Reference j)
STS-005-034, Survey Unit Classification (Reference k)
STS-005-035, Preparation of Survey Unit Release Records (Reference d)
SIC-MA-Q-25, FSS Survey Unit Inspections After Surveys are Completed (Reference l) 1.1 Survey Planning The Data Quality Objectives (DQO) process is incorporated as an integral component of the data life cycle of the NSS FSS program. This process, described in MARSSIM, is a series of planning steps found to be effective in establishing criteria for data quality and developing survey plans. DQOs allow for systematic planning and are specifically designed to address problems that require a decision to be made and provide alternate actions. The DQO process is flexible (i.e., it employs a graded approach) in that the level of effort associated with planning a survey is based on the complexity of the survey and nature of the hazards. Finally, the DQO process is iterative, allowing the survey planning team to incorporate new knowledge and modify the output of previous steps to act as input to subsequent steps.
The DQO process was used in the FSS planning phase for scoping, characterization, remediation, and FSS package development.
The DQO process consists of performing the following seven steps:
State the Problem; Identify the Decision; Identify the Inputs to the Decision; Define the Boundaries of the Decision; Develop a Decision Rule; Specify Tolerable Limits on Decision Errors; and, Rev. 0 15
Final Status Survey Final Report 1 of 5 Optimize the Design for Obtaining Data.
These DQO process steps were completed for each FSS package.
1.2 Survey Design The survey design was a MARS SIM based approach using a combination of static measurements and scans in each survey unit. Visual Sample Plan (VSP) (Reference m) software was used to create maps and to select systematic sample locations for Class 1 and Class 2 survey units and random locations for Class 3 survey units.
The number of measurements for each survey unit was determined in accordance with STS-005-031. The relative shift 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. The optimal value for the relative shift should range between one (1) and three (3). If the relative shift is less than one (1), or greater than three (3), then the value of two (2) will be used for the relative shift.
Each Class 1 and Class 2 survey unit bad a Remedial Action Support Survey (RASS) performed prior to turnover to the FSS staff. That data was used to both calculate sigma ( cr) and determine whether the survey unit could pass the FSS data assessment.
Class 3 survey units did not have a RASS or turnover survey performed because they inherently have a very low probability of being contaminated with licensed materials above 10% of the DCGL. Therefore, STS-005-031 specifies using a value of 0.3 as an estimate of the standard deviation. The lower boundary of the gray region was set at 0.5 and the DCGL set to 1. The relative shift was calculated as 1.67 and rounded up to 1. 7.
The sample size in all cases was determined from Table 5.5 ofMARSSIM with a Type I and Type II error of0.05.
Each survey design specified the method and location for collection of static measurements and scan coverage. Scan coverage for each survey unit followed the scanning coverage presented in L TP Table 5-3, presented as Table 2-1 below.
Table 1-1 Traditional Scanning Coverage Requirements Survey Unit Classification Required Scanning Coverage Fraction Class I 100%
Class 2 Decks, or lower bulkheads of rooms: 10% to 100%
Upper bulkheads or overheads: 10% to 50%
Class 3 Judgmental Systems and Components Judgmental Each survey design specified the collection of 2 judgmental and 1 duplicate measurement for Quality Control (QC) purposes. Investigation Levels are also specified in the survey design. Confirmatory measurements are required when an investigation level is exceeded.
The product of the survey design process is an FSS package, which addresses various elements of the survey, including, but not limited to:
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Final Status Survey Final Report 1 of 5 Maps of the survey area showing the survey unit(s) and measurement/sample locations, as appropriate; Applicable DCGLs; Instrumentation to be used; Types and quantities of measurements to be made or collected; Investigation criteria; Quality Assurance (QA)/QC requirements (e.g., replicate measurements);
Applicable health and safety procedures; and, Applicable operating procedures.
1.3 Survey Implementation FSS field activities were considered work and were subject to the STS 002-011 Work Control Process procedure. Master work packages were developed, incorporating all applicable site req~irements, and the work was scheduled. The FSS packages described above formed the technical scope for field surveys.
Prior to performing the FSS, each survey unit was walked down and turned over to the FSS staff. This was performed under STS-005-032. Each survey unit was inspected to ensure all decommissioning activities were 1) complete and 2) any unsatisfactory conditions had been resolved. Isolation and controls were implemented. Large area smear surveys in regularly accessed areas of Class 3 survey units are used to determine whether radioactive material has been reintroduced to these survey units. The controls and smears will remain in effect until license termination.
Prior to starting a survey, the survey team was briefed on the FSS package. Each package has a daily journal to record important information and logs to record static measurement and scan data. There are logs to record instrument operability checks before and after the surveys.
Radiological surveys were performed with the following instrumentation:
Ludlum model 3002 with a Ludlum model 43-93 dual-phosphor scintillation detector (direct static beta measurements and beta scans)
Ludlum model 3002 with a Ludlum model 43-37 gas flow proportional detector (beta scans)
Total surface activity measurements were collected with the detector in contact with the surface. Beta scan data with the Ludlum 43-93 detector was collected by holding the detector at approximately 0.75 inches above the surface and moving at a speed of one (1) detector width per second. The Ludlum 43-37 detector was on wheels with the detector height set at 0.75 inches and moved at a speed of one (1) detector width per second.
1.4 Radiological Release Criteria The significant Radionuclides of Concern (ROC) identified in the Contractor Report (CR) -109, RC/CV Characterization Report (Reference n) were Co-60, Cs-137, and Ni-63. Characterization data in CR-109, measurements for alpha activity showed no significant alpha activity was present. CR-139, Calculations to Support NS SAVANNAH Surface Contamination DCGLs (Reference o) confirmed that Co-60, Cs-137 and Ni-63 comprise approximately 99% of the total residual radioactivity on the ship.
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 from the initial suite. Table 2-2 presents Rev. 0 17