ML103060331

Final Status Survey Report - Attachment 2 - Revision 1, Service Equipment Building (Building 1131)

ML103060331
Person / Time
Site:	Plum Brook
Issue date:	10/25/2010
From:	Mann B US National Aeronautics & Space Admin (NASA)
To:	NRC/FSME
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Download: ML103060331 (70)

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Plum Brook Reactor Facility Final Status Survey Report Attachment 2 Revision 1 Service Equipment Building (Building 1131)

FINAL STATUS SURVEY REPORT ROUTING AND APPROVAL SHEET.

Document

Title:

Final Status Survey Report, Attachment 2 Service Equipment Building (Building 113 1)

Revision Number: 1 ROUTING SIGNATURE DATE Prepared By B. Mann ,a-*-* -to Prepared By N/A REVIEW & CONCUR9 Independent Technical Reviewer R. Caseo Other Reviewer, QA Manager J. Thomas . "

Other Reviewer FSS/Characterization Manager W. Stoner 1.01. slz.)

NASA Project Radiation Safety Officer W. Stoner r110 ii

NASA PBRF DECOMMISSIONING PROJEC ,T CHN:E/CL

,: LCE LL: .N ":ECORD DOCUMENT TITLE: Final Status DOCUMENT NO: NA REVISION NO: I Survey Report, Attachment 2, Service Equipment Building (Building 1131)

Revision 0: Initial issue of Report Revision 1:

Cover page - page number is removed.

List of Effective Pages page number is corrected from i to iv.

Table of Contents page number is corrected from ii to v.

List of Tables and List of Figures page number is corrected from iii to vi.

List of Acronyms & Symbols page numbers are corrected from iv to vii and v to viii.

Sections 2.4 & 3.1 were revised to update the building status (building demolished in July-Aug 2010) and disposition of materials.

In response to an NRC comment, a note was added to Table 3 and an explanatory paragraph added to Section 4.4 to explain the use of the DCGL, instead of the DCGLEMC, as the scan investigation-action level in Class 1 survey units.

Table 7 notes are revised in response to NRC comments to identify designs that did not adjust the DCGL for the presence of embedded piping (EP) and did not adjust the DCGL for deselected insignificant radionuclides.

Section 5.1 text is revised in response to NRC comment to clarify how scan investigations were initiated in survey units SE-3-1 and SE-3-2.

Section 5.1 text is revised in response to NRC comment. The first bullet following paragraph 2 and the first bullet following paragraph 3 on page 23. are edited to clarify that the Table 6 referred to is in the Survey Design No. 10 report, not the present report.

Table 11 and Table 11 notes are revised in response to NRC comment as follows:

• Survey units are identified for which the DCGL was not adjusted in the survey design to account for 1 mrem dose from EP.

Survey units are identified for which the DCGL was not adjusted in the survey design for the 2.5 mrem dose contribution from "insignificant radionuclides".

Table 11 was also modified by the addition of a column to show that a check was performed to verify that the total dose was less than 25 mrem/y considering the contributions from residual contamination, embedded piping and insignificant radionuclides.

The introductory paragraph of Section 5.2 was edited to clarify the evaluations presented in Table 11. The associated footnote which concluded that "average SEB residual activity levels are indistinguishable from background", was removed.

Miscellaneous typographical errors are corrected. These include Table 7 header column entries corrected to show the symbol characters A, a and A/a which were not accurately converted when the document was converted from a Word document to a "pdf' document (Adobe Acrobat). Also, the acronym "LGBR" was corrected to "LBGR" in several places in the document. Several grammatical and punctuation errors were corrected.

Other errors found in proof-editing were corrected. In Table 7, the DCGL and LBGR were corrected (changed from 27,166 to 26,079 and 21,718 to 20,631 dpm/100-cm 2 , respectively). In Table 10, the QC Replicate Scan Coverage percentages for survey units SE-I-11, 1-12, 2-3 & 2-4 were corrected.

SForm AD-01/3 Rev 1 111°.

Plum Brook Reactor Facility FSSR Attachment 2, Rev. 1 LIIST OF EFFECTIVE PAGES~

DOCUMENT NO: NA REVISION NO: 1 Page No. Revision Level Page No. Revision Level Page No. Revision Level Cover Page I Routing & Approval Sheet Change/Cancellation 1 Record LOEP TOC 1 List of Tables & List of Figures List of Acronyms &

Symbols, 2 pages Text, pages 1 through 1 30 Appendix A 0 32 pages Appendix B 0 82 pages I I U I 4 .1. .5.

4 4. 4 4.

4. 4 4. 4 I & i I Form AD-O1/5 Rev 2 iv

Plum Brook Reactor Facility FSSR Attachment 2, Rev. I TABLE OF CONTENTS 1.0 Introduction .................................................................................................................... 1 2.0 SEB D escription ...................................................................................................... 2 2.1 Building Construction ............................................................................................ 2 2.2 Building System s and Services .............................................................................. 4 2.3 Building M odifications ............................................................................................. 4 2.4 Final Configuration and Scope ................................................................................ 5 3.0 SEB History and Operations with Radioactive Materials ...................................... 5 3.1 Chronology ............................................................................................................ 5 3.2 O perations w ith Radioactive M aterial .................................................................... 7 3.3 D isposition of M aterial in the Post-Shutdow n Period ............................................ 8 3.4 D ecom m issioning ................................................................................................... 9 Table 1, Contaminated Areas Identified in SEB Decommissioning Surveys ........................ 9 4.0 Survey Design and Implementation for the SEB .................................................. 10 4.1 FSS Plan Requirem ents .......................................................................................... 10 4.2 SEB Area Classification and Survey Unit Breakdown .......................................... 12 4.3 N um ber of M easurem ents and Sam ples ............................................................... 14 4.4 Instrum entation and M easurem ent Sensitivity ...................................................... 18 5.0 SEB Survey Results ................................................................................................. 20 5.1 Surveys and Investigations .................................................................................. 20 5.2 Fixed M easurem ents and Tests ................................................................................ 23 5.3 ALA RA Evaluation .............................................................................................. 26 5.4 Com parison w ith EPA Trigger Levels .................................................................. 28 5.5 Conclusions .......................................................................................................... 28 6.0 R eferences ..................................................................................................................... 29 7.0 A ppendices .................................................................................................................... 30 Appendix A - Exhibits ..............................................................................................................

Appendix B - Survey Unit Maps Showing Measurement Locations & Fixed Measurement D ata ...........................................................................................................................................

v

Plum Brook Reactor Facility FSSR Attachment 2, Rev. I LIST OF TABLES Table 1, Contaminated Areas Identified in SEB Decommissioning Surveys ............................. 9 Table 2, SEB Radionuclide Activity Fractions and Gross Activity DCGLs ................................ 11 Table 3, Based Survey Scan Coverage and Action Level Requirements ..................................... 11 Table 4, SEB Survey Units for FSS ......................................................................................... 12 Table 5, SEB Survey Unit Breakdown .................................................................................... 14 Table 6, SEB Survey Unit Breakdown by MARSSIM Classification .................. 14 Table 7, SEB Survey Design Sum m ary ..................................................................................... 16 Table 8, VSP Sensitivity Analysis Results for Survey Unit SE-2-1 Design ........................... 17 Table 9, Detection Sensitivities of Field Instruments ............................................................... 19 Table 10, Scan Survey Results .............................. ............. 21 Table 11, SEB Total Surface Beta Activity Measurement Summary and Test Results ........... 24 Table 12, Screening Level Values for SEB and Radionuclide Activity Fractions ................... 27 LIST OF FIGURES Figure 1, PBRF NW Area Showing Reactor Building, SEB and Support Buildings ................. 3 vi

Plum Brook Reactor Facility FSSR Attachment 2, Rev. I LIST OF ACRONYMS & SYMBOLS (X alpha A Area AEMC Area corresponding to the area factor calculated using the scan MDC AEC Atomic Energy Commission ALARA As Low as Reasonable Achievable AF Area Factor P beta CFR Code of Federal Regulations CoC Chain-of-Custody cm centimeters 2

cm square Centimeters cpm counts per Minute CPT Cold Pipe Tunnel a delta, the average residual activity in the survey unit A delta, DCGLw - LBGR DCGL Derived Concentration Guideline Level DCGLEMC DCGL for small areas of elevated activity, used with the Elevated Measurement Comparison test (EMC)

DCGLES Effective Surface DCGL DCGLG Gross activity DCGL DCGLGB Gross beta activity DCGL DCGLsur Surrogate activity DCGL DCGLw DCGL for average concentrations over a large area, used with statistical tests dpm disintegrations per minute DQA Data Quality Assessment DQO Data Quality Objective EMC Elevated Measurement Comparison EPA Environmental Protection Agency FSS Final Status Survey FSSP Final Status Survey Plan FSSR Final Status Survey Report ft feet 7 gamma g gram HTD Hard To Detect L Grid dimension LMI Ludlum Measurements, Inc.

LBGR Lower Bound of the Gray Region 2

m square meters pCi microCurie MARSSIM Multi-Agency Radiation Survey and Site Investigation Manual MDC Minimum Detectable Concentration vii

Plum Brook Reactor Facility FSSR Attachment 2, Rev. 1 LIST OF ACRONYMS. Continued MDCscan Minimum Detectable Concentration for scanning surveys MDCstatic Minimum Detectable Concentration for static surface activity measurements MDCR Minimum Detectable Count Rate ml milliliter mrem millirem MWH Montgomery Watson Harza, Inc.

NASA National Aeronautics and Space Administration N Number of FSS measurements or samples established in a survey design NA Not Applicable Nal Sodium Iodide NEMC number of measurements or samples determined using the elevated measurement comparison test NRC Nuclear Regulatory Commission PBRF Plum Brook Reactor Facility pCi/g picocuries per Gram QA Quality Assurance QC Quality Control RESRAD RESidual RADioactive - a pathway analysis computer code developed by Argonne National Laboratory for assessment of radiation doses. It is used to derive cleanup guideline values for soils contaminated with radioactive materials RESRAD-BUILD A companion code to RESRAD for evaluating indoor building contamination and developing site-specific DCGLs ROLB Reactor Office and Laboratory Building, Building 1141 RPD Relative Percent Difference o generic symbol for standard deviation of a population Cyb standard deviation of background measurements on standard deviation of net activity measurements at total estimated standard deviation of surface activity measurements SEB Reactor Service Equipment Building, Building 1131 TBD Technical Basis Document WEMS Water Effluent Monitoring Station VSP Visual Sample Plan WRS Wilcoxon Rank Sum Test viii

Plum Brook Reactor Facility FSSR Attachment 2, Rev. 1 1.0 Introduction This report presents the results of the final status radiological survey of the Plum Brook Reactor Facility (PBRF) Service Equipment Building (SEB). This is Attachment 2 of the PBRF Final Status Survey Report (FSSR). This document describes the SEB, its operational history and final condition for the final status survey (FSS). It describes the methods used in the FSS and presents the results of the survey measurements.

As stated in the Plum Brook Reactor Facility Final Status Survey Plan (FSSP) [NASA 2007], the goal of the decommissioning project is to release the facility for unrestricted use in compliance with the criteria in US NRC 10CFR20 Subpart E. The principal criterion is that the dose to future site occupants will be less than 25 mrem/y. In addition, levels of residual contamination will be reduced to achieve doses as low as reasonably achievable (ALARA) below 25 mrem/y. A Derived Concentration Guideline Level (DCGL) for residual surface contamination has been established for the SEB, Considering the radionuclide mixture established for the SEB, the gross beta DCGL is 27,166 dpm/100-cm2 . However, the DCGL for the entire length of the Cold Pipe Tunnel is 11,000 2

dpm/100-cm2.

The survey measurement results and supporting information presented herein demonstrate that residual contamination levels in each survey unit of the SEB are well below the DCGL. Additionally, it is shown that residual contamination has been reduced to levels that are consistent with the ALARA requirement. Therefore, the SEB meets the criteria for unrestricted release.

Section 2.0 of the report provides a description of the SEB. This includes the building layout, its relation to other PBRF buildings and facilities, design and materials of construction, building contents and use, systems and services, building modifications, final configuration of the SEB for the FSS and scope of the FSS for this building.

A brief history of operations is presented in Section 3.0. A chronology of significant milestones is followed by history of operations with radioactive materials. Post shutdown and decommissioning activities are summarized.

Section 4.0 presents the FSS design for the SEB. This includes FSS Plan requirements applicable to the SEB, breakdown into survey units and assignment of MARSSIM classification to each, the survey design approach, and instrumentation used for the FSS and measurement sensitivities.

Survey results are presented in Section 5.0. This section includes a summary of the FSS measurements performed in all SEB survey units, comparison to the DCGL and a discussion of residual contamination levels relative to the ALARA criterion.

The report of Final Status Survey results for the PBRF, including the SEB, will provide the basis for requesting termination of NRC Licenses TR-3 and R-93 in accordance with 10CFR50.82(b)(6).

1

Plum Brook Reactor Facility FSSR Attachment 2, Rev. 1 Supporting information is contained in Appendices. Appendix A contains photos and schematics to supplement the text. Survey design maps and tables of coordinates for the measurement locations in each survey unit are provided in Appendix B.

2.0 SEB Description The SEB is a three-story structure consisting of a basement, main floor, and mezzanine elevation.

There is an addition attached to the east side of the building, with a high bay and three offices on the mezzanine. The SEB housed water processing equipment, air compressors, electrical control equipment, diesel generators for emergency electrical power, and the health physics radiochemistry/analytical laboratory. The CPT was located at the -15 foot level and extended east to the cooling tower and overhead water storage tanks area and west to the Primary Pump House and the Reactor Building. It contained the piping associated with all the water, gas, service and auxiliary air, steam and other ancillary support systems.

The SEB was designed to treat Lake Erie water using process equipment to clarify and de-ionize the lake water; provide emergency diesel electric power; supply service and instrument air for facility and experiment use; deliver steam to the entire facility; and provide a backup control console with capability to safely shutdown the 60 MW nuclear test reactor. It also housed personnel offices, an environmental radiological counting laboratory and a chemical test laboratory for water treatment analysis. Initial construction began in 1957 and the building was completed in about 1960, prior to reactor startup in 1961.

There also were a number of ancillary facilities connected to the SEB. These included the main electrical substation, the water treatment precipitator, two utility air intakes, two diesel fuel oil tanks, a waste oil tank, and the above utility tunnel.

The SEB, identified as Building 1131, is shown on the PBRF site map in Figure 1. A recent (2009) photograph of the SEB is provided in Exhibits 1, 2 and 3 of Appendix A.

2.1 Building Construction The SEB was principally constructed in the 1958 -1960 time frame. Later, facility modifications occurred several times to improve operations.

The basement of the SEB consisted of three main excavated areas totaling roughly 6,300 square feet. The south side contained approximately 1400 square feet of excavated area that included an electrical room with batteries, a stairwell to the Equipment Control Room, a pit area off the east side of the electrical room and trenches for two large utility air receiver tanks and associated piping. The area between the south side of the basement and the north side was 1900 square feet of utility tunnel. The north portion of the basement contained an excavated area of approximately 3000 square feet that housed an auxiliary equipment room, a water treatment pump room and a large clear-well for processed water (part of the water treatment plant).

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Plum Brook Reactor Facility FSSR Attachment 2, Rev. 1 The first floor of the SEB contains about 15,700 square feet of total space. A low roofed one-story section on the west side included two offices, rest rooms, a janitors closet, a chemical test laboratory, a counting room and an equipment control room with reactor shutdown capability. The exterior front section was concrete and the remainder of the building was two stories of fluted metal siding; all windows were steel sash "Solex". The high bay area contained the water treatment area with a chlorine room, sand filters, pumps, a clear well storage tank and de-ionizers; a large room with two boilers; a storage area; and a locker room on the north side. The south side contained an engine room with two associated plumbing plus a general shop and equipment area. The two-story Annex, located in the southeast comer of the building, contained a shop and equipment area.

The second floor (mezzanine) consisted of about 2,100 square feet of chemical storage (lime, alum, etc.) and the upper parts of the chemical feeders for water treatment. In addition, the SEB Annex second floor contained about 800 square feet for two offices and a shop area.

Figure 1, PBRF NW Area Showing Reactor Building, SEB and Support Buildings 5EB -5EKVICF-5 EQUIPMENT BUILDING 11L FH - FAN MOU5E WHB - WASTE HANDUNG BUILDING PPH - PRIJMARY PUMP HOUSE ROLB - REACTOR OFFICE 4 LABORATORY BUILDING HRA - HOT RETENTION AREA 3

Plum Brook Reactor Facility FSSR Attachment 2, Rev. 1 2.2 Building Systems and Services The principal operational activities at that time were the startup and testing of all the reactor facility support systems contained in the SEB, i.e., the water treatment plant, the diesel systems, the boilers, utility air systems, electrical power feed and control systems, etc.

During the reactor operations period of 1961 through early 1973, the SEB services were operated continuously to fulfill their support role. Three personnel were normally for continuous three shift manning of the SEB during reactor operations - a water treatment operator, a roving electrician and an Equipment Control Room operator.

During the day shift, there was a large number of other support personnel (electricians, mechanics, supervisors, lab technicians, etc.) assigned to support operations, perform corrective and preventative maintenance and make system modifications facility-wide. The SEB staff also supported implementing facility changes and system upgrades to improve the effectiveness and efficiency of reactor operations.

2.3 Building Modifications Facility modifications occurred several times to improve operations such as the addition of a 2,200 square foot Annex in the 1964-1965 time frame, replacement of four small diesels generators with two larger units, and remodeling to create a separate radioactivity counting room.

Until modifications, made in 1965, the Chemical Test Laboratory, Room 1, was used to perform analysis on PBRF water systems, such as: raw water, process water, de-ionized water, cooling tower water, domestic water, boiler water and condensate, effluent water (WEMS), along with Plum Brook Station stream and sewage water. It was also used to perform routine and special radiometric analysis on facility and environmental air, charcoal, water, smears, vegetation, soils and silts, atmospheric fall out, aquatic biota and selected biological samples (milk, animals, etc.). Modifications in 1965 converted an adjacent office area, Room 2, into a counting room. All radiometric work was then done in this room until shutdown, in 1973.

In addition, a fume hood was installed in Room 1, which brought the total of fume hoods to two. Both hood exhausts were tied together and vented through the roof. The hood sink drains were connected to the building sanitary system, which emptied into the sewage sump in the basement. Natural gas, deionized water, hot domestic water, service air and a localized vacuum system were supplied to the hoods for sample preparation and chemical analysis work.

Between termination of reactor operations on January 5, 1973 and June 30, 1973, the SEB services were placed in a standby status similar to the rest of PBRF. The PBRF end condition statements governed the status of each system for the protected safe shutdown mode. General 4

Plum Brook Reactor Facility FSSR Attachment 2, Rev. 1 building conditions such that areas were left clean and void of miscellaneous equipment, materials and supplies governed the status of the SEB itself. Desks, tables, filing cabinets, bookcases, etc. were cleaned out and left. Rest rooms were taken out of service. Water fountains were deactivated and drained. The four large fans were removed from the top of the wooden cooling tower and were stored in the SEB Annex. The building was closed and locked.

2.4 Final Configuration and Scope Configuration of the SEB for the FSS and the period until license termination is controlled by PBRF decommissioning and FSS procedures. For the FSS, the structure was intact with utilities and services limited to temporary lighting. All furniture, furnishings and equipment were removed. Most floor coverings, wall coverings and false ceilings, electrical conduit, drains, HVAC ducts, hood ventilation ducts and plumbing fixtures were removed. All piping was drained and removed and all sumps deactivated, except for the north sump which was maintained active to control groundwater intrusion (see Exhibits 8 and 9 of Appendix A).

The scope of FSS measurement results reported in this attachment includes building interior and exterior surfaces. It includes surface attachments, temporary safety covers and small embedded fixtures, for example pipe and conduit stubs such as shown in the lower photograph of Appendix A, Exhibit 10. It does not include FSS measurement results for piping embedded in SEB concrete buried beneath or adjacent to the building (an example is shown in the upper photograph in Appendix A, Exhibit 10). The FSS results for these commodities are reported in separate attachments to the FSS Report.

The SEB was demolished in the summer of 2010. The structural steel and other metals were segregated for free release surveys under PBRF radiological control procedures (no detectable activity per Procedure RP-008).

3.0 SEB History and Operations with Radioactive Materials A chronology of SEB milestones is given below. This is followed by a discussion of the significant phases of SEB construction, operation and post-shutdown activities. Emphasis is on information pertainingto radiological operations that could affect the final building condition and final status survey.2 3.1 Chronology 1956 - September, groundbreaking for PBRF 1957 - SEB construction initiated 2 Information sources for the history and pre-decommissioning period include, construction photos, construction drawings, PBRF operating cycle reports, Radiochemistry periodic reports, PBRF Annual Reports, Unusual Occurrence Files, memoranda and other historical files maintained by PBRF Document Control.

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Plum Brook Reactor Facility FSSR Attachment 2, Rev. 1 1959 - Jan-Feb. Initial SEB occupancy 1961 - June, 60 Mw Test Reactor critical 1963 - April, 60 Mw Test Reactor reaches full power 1973 - January 5 th, Reactor shutdown 1973 - June 30, SEB vacated and placed in "standby condition". New Reactor Fuel and radioactive sources removed 1986 - New roof installed on SEB 1987 - The Teledyne Isotopes Characterization survey reported that the SEB was not surveyed because it was a clean area "previously verified to be in an uncontaminated condition". It should be noted that no survey data was presented to document this "uncontaminated condition".

1998 - Additional roofing work on SEB 1998 - GTS Duratek Confirmatory Survey showed no loose contamination. Fixed beta/gamma activity ranged from 260 to 485 dpm/1 00 cm 2 in the SEB addition.

There is no evidence of fixed alpha surveys being performed.

2001 - The Historical Site Assessment, conducted in 2001, identified evidence that indicated the presence of radioactive contamination in structures classified as non-impacted (e.g., Service Equipment Building 1131).

2002 - PBRF Decommissioning Plan approved. Equipment and cabinets removed; initial building decontamination.

2003 - In January, 2003 MWH characterization package D 1131 401C 1 was written for loose equipment and material. The highest fixed plus removable contamination beta. levels were 109 dpm/1 00 cm2,22 alpha, and 74,891 dpm/100 cm 2 ,

2003- 2005 - Temporary storage of contaminated equipment in SEB during D&D of the PBRF. Two pieces of stored equipment were identified as containing fixed radioactive contamination.

2004 - MWH characterization package for the basement of the SEB identified activity, by direct measurement, to a maximum level of 16 dpm/100 cm 2 ,

2 alpha, and 1,021 dpm/1 00 cm , beta. As a result of this survey, the area was re-classified from non-impacted to Impacted Class 2.

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Plum Brook Reactor Facility FSSR Attachment 2, Rev. 1 2006 - The SEB basement was surveyed under Survey Request (SR) 32. All smears were <MDA for both alpha and beta activity and the highest fixed activity, of the 26 measurements taken, was 7,708 dpm/100 cm 2 , beta. The average of the other 25 measurements was 438 dpmr100 cm 2 .

2006 - During performance of work for SR 32, it was determined that Sump #4, located in the Cold Pipe Tunnel portion of the SEB basement, accumulates water from the entire SEB and the entire Cold Pipe Tunnel, a decision was.

made to re-classify it as Impacted Class 1.

2006 - 2007 Remediation was performed on the contaminated areas of SEB and preparation for FSS.

2008 - FSS measurements completed in SEB interior.

2009 -, Roof covering removed.

2009 - FSS measurements of SEB roof and exterior walls completed.

2010 - Building demolished.

i3.2 Operations with Radioactive Material A review of the Health-Safety Operations Office input to the reactor cycle reports showed the de-ionized water to the SEB laboratory was contaminated during at least 4 reactor cycles (39, 76, 82 and 136) from 1965 to 1971. The maximum contamination level noted was 0.002 [tCi/ml. This water was used to wash and polish glassware and for sample preparation. Thus, there was a potential impact on the sanitary drains and sewage sump because of the waste from use of the contaminated de-ionized water.

During reactor cycle 82, on 11-7-68, draining of the de-ionized water header in the CPT inadvertently resulted in a large quantity of contaminated water flowing from the floor to the SEB -15' floor area. Transferable contamination levels of 100,000 dpm/100 cm2 were noted in areas contacted by the water. The cold drains in the CPT were also affected by this spill. These drains were connected to the SEB cold sump, which then pumped to the storm drain system.

Radiometric samples were prepared in the fume hoods such as water, vegetation, soils and silts, atmospheric fall out, aquatic biota and biological samples and then dried.

The samples would then be passed to the counting room and counted in one of two low-level background counters. Occasionally, higher activity radioactive samples would be encountered; such as smears, air (particulate) and water samples.

Sealed radioactive calibration sources were used to calibrate the counters, for example, Pb-210, U-238, Sr-90, Cs-137 and Ra-226. The sources were either disposed of or 7

Plum Brook Reactor Facility FSSR Attachment 2, Rev. 1 transferred to Bldg 7143 at PBS at shutdown. Both low level counters were transferred to Bldg. 7143 after shutdown.

There were no hot drains or sumps or related systems located in the SEB because it was intended that no unsealed radioactive materials would be processed there.

Subsequent to July 1, 1973, the SEB was controlled according to Nuclear Regulatory Commission Licenses TR-3, R-93 and Broad By-Product Material License BPL No.

34-06706-03. The annual reports to the NRC provide the details of significant events or changes in status during the period between 1973 and the approval of the PBRF Decommissioning Plan in 2001. In 1995, the original 4 ply roofing materials of the SEB were removed and a layer of foamed polyurethane material was replaced to prevent significant water leakage into the SEB. Also, in 1983-1984, the wooden cooling tower and the above grade portions of the concrete basin were removed.

3.3 Disposition of Material in the Post-Shutdown Period Notification was received on January 5, 1973 that NASA was terminating all nuclear related operations at PBRF due to budget constraints. The test reactor, mock-up reactor, hot laboratory and all associated operations were to be placed in standby condition by June 30, 1973. This included termination of the reactor facility operations staff.

Following notification, the test reactor (60 MW) was immediately shutdown on January 5th. A Master Plan was developed to address the activities associated with terminating the operating licenses for PBRF and placing the facility in a standby status. End condition statements were developed. These specified the final conditions for all buildings, structures and equipment on the PBRF site as of June 30, 1973. Both the initial Master Plan and the End Condition Statements were subject to revision as activities progressed or conditions changed.

Services to the building were terminated with the exception of electricity and the operation of one sump in the basement. Sanitary systems and water were cut off, the heating system was secured, and laboratory hoods were tagged and the access doors cabled shut to prevent entry.

All source (i.e., natural uranium) and special nuclear material were removed from the facility; except for calibration sources covered by general licenses per 10CFR70 and 10CFR40.

During the period between mid-1973 and the start of decommissioning in 2002, activities at PBRF were controlled according to modified AEC/NRC licenses TR-3, R-93 and BPL No. 34-060706-03. SNM-605 was apparently terminated in 1973; the by-product license No. 34-060706-03 was terminated in May, 1982. Licenses TR-3 and R-93 then controlled and authorized possession only of the remaining radioactive 8

Plum Brook Reactor Facility FSSR Attachment 2, Rev. 1 materials on-site, i.e., no facility operations were permitted. During 1973 to 2002, selected equipment, materials, and waste (both low-level radioactive and non-radioactive) were removed to other locations or discarded as the projected long-term considerations for the facility changed from possible restart to standby to decommissioning. For a brief history of the activities during this period, see the NASA PBRF Decommissioning Plan, Section 1.2.1 Decommissioning Historical Overview

[NASA 2007a].

3.4 Decommissioning In addition to removal of bulk equipment and furnishings, D&D activities focused on decontamination of known contaminated areas identified in the initial decommissioning characterization surveys. Also, surface coverings and fixtures that could mask contamination or physically interfere with surface activity measurements were removed. This included removal of floor tiles, ceiling acoustic tile and wall coverings. Hazardous materials and many building features, except structural components, have been removed from the building to facilitate the Final Status Survey. Recyclable items were segregated where possible.

Characterization, decommissioning support and post remediation radiological surveys were performed throughout the decommissioning process. The objective of the final post-remediation survey was to ensure that the SEB was ready for the FSS and could satisfy the release criteria with a high probability of success.

A summary of the areas in the SEB where contamination was measured and remediated during D&D is provided in Table 1. Note that these results do not include surveys of contaminated equipment or bulk contaminated items that were removed and disposed of as radioactive waste.

Table 1, Contaminated Areas Identified in SEB Decommissioning Surveys Room No. or Contamination levels Radionuclides Results, Survey ID Location Measured and Date Roof and Building Up to 699 dpm/100-cm 2 No sample analysis MWH D1131 405C1, Exterior beta total surface activity reported 4/2004 Cold Pipe Tunnel Up to 16 dpm/100-cm 2 No sample analysis MWH D1 131 406C1, alpha and up to 92,897 reported 4/2004, Tunnel dpm/1 00-cm 2 beta fixed Remediated (1) activity Cold Pipe Tunnel 5,941 dpm/100-cm 2 beta 66 pCi/g Co-60 and 0.9 MWH D1131 406C1, sediment sample total surface activity pCi/g Cs-137 4/2004, Trench from drainage Remediated ()

trench Mezzanine Room Hot particle discovered Gamma spec sample MWH DI 131 404C1, 19A on floor 92,158 dpm/100-cm2 beta results on hot particle 4/2004, Smears all <

and 23 dpm/100-cm2 were 17,507 pCi of Cs- MDA for alpha and beta.

alpha 137 9

Plum Brook Reactor Facility FSSR Attachment 2, Rev. 1 Table I Note:

1. Remediation goals varied somewhat through the decommissioning period, but were generally lowered to < 5,500 dpm/100-cm 2 total surface beta activity and < 20 dpm/100-cm 2 total surface alpha activity during final post-remediation surveys.

4.0 Survey Design and Implementation for the SEB This section describes the method for determination of the number of fixed measurements and samples for the FSS of the SEB. Requirements of the FSS Plan applicable to the SEB are summarized. These include the DCGLw3 , the gross activity DCGL that applies to the SEB, scan survey coverage and action-investigation levels, classification of areas and breakdown of the SEB survey units. The radiological instrumentation and their detection sensitivities are discussed.

4.1 FSS Plan Requirements The DCGLs for individual radionuclides were obtained for PBRF structures considering exposure to future site occupants from two potential pathways. Single radionuclide DCGLs were calculated using RESRAD-BUILD Version 3.22 for a building reuse scenario. Single radionuclide volumetric DCGLs were calculated for subsurface structures using RESRAD Version 6.21 for a resident farmer scenario. 4 The volumetric DCGLs (in pCi/g) were converted to "effective surface" DCGLs (in dpm/100-cm 2) using surface-to-volume ratios for the assumed volume of contaminated subsurface concrete. The DCGL calculations are described in the FSSP, Attachment B. To obtain the DCGLs for PBRF structures, the smaller of the two DCGLs calculated for each of the radionuclides of concern were selected.

For structural surfaces in the PBRF, where multiple radionuclides are potentially present in residual contamination, the DCGL for FSS design and implementation is a gross activity DCGL. The gross activity DCGL accounts for the presence of multiple radionuclides, including beta-gamma and alpha emitters. The gross activity DCGL can also include so-called hard-to-detect (HTD) radionuclides. The latter are not detected, or detected with very low efficiency, by the beta detectors selected for the FSS of structures.

3 The convention in MARSSIM is to identify the DCGL used as the benchmark for evaluating survey unit measurement results, as the DCGLw. The "W" subscript denotes "Wilcoxon", regardless of the particular test used: Wilcoxon Rank Sum Test, or Sign Test.

4 Potential exposure to future occupants from subsurface structures could occur from contaminated concrete rubble placed as fill and from contaminated intact structures such as the below-grade portion of the Reactor Bioshield.

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Plum Brook Reactor Facility FSSR Attachment 2, Rev. 1 The gross activity DCGLs were calculated for PBRF structures using the best available information on radionuclides identified and their activity ratios. Activity fractions and gross activity DCGLs for the SEB are shown in Table 2. The default DCGL for PBRF structures, 27,166 dpm/1 00-cm2, is applied to the SEB. However, the DCGL for the entire length of the Cold Pipe Tunnel is 11,000 dpm/1 00-cm2.2 5 Table 2, SEB Radionuclide Activity Fractions and Gross Activity DCGLs Radionuclides H-3 Co-60 Sr-90 1-129 Cs-137 Eu-154 U-234 U-235 DCGLw Location (dpm/100 Activity Fractions Assigned to SEB T)

Areas 0.2707 0.0965 0.0788 0.0142 0.4671 0.0012 0.0698 0.0017 27,166 Outside the CPT CPT 0 1.000 0 0 0 0 0 0 11,000 (entire length)

Table 2 Note:

1. Activity profiles and gross activity DCGLs for structures are reported in the Technical Basis Document PBRF-TBD-07-001 [PBRF 2007]. Only a small fraction of characterization smear and material samples from the SEB showed detectable activity. Thus, the SEB was assigned the default radionuclide mixture. The default activity fractions were obtained as the averages of radionuclide activity fractions in 18 characterization samples.

Requirements for scan coverage and investigation levels are derived from the MARSSIM classification of survey units. The values applicable to the SEB are shown in Table 3.

Table 3, Based Survey Scan Coverage and Action Level Requirements Scan Survey Scan Investigation Sai Measurement Static esrmn Classification SC uveye Sn velst i or Sample Result nCoverage Levels Investigation Levels Class 1 100% >DCGLEMC >DCGLEMC Class 2 10 to 100% >DCGLw or >MDCs~anI if MDCscan is >DCGLw Class 3 Minimum of 10% >DCGL>or >MDCscan >50% of the DCGLw if MDCan is >DCGLw 5 Data from smear samples and concrete samples collected in multiple characterization-sampling surveys in the period from approximately 2002 though 2007 were evaluated to develop activity profiles for the various PBRF structures.

Activity profiles and gross activity DCGLs for structures are reported in the Technical Basis Document PBRF-TBD 001 [PBRF 2007]. Since only a small fraction of characterization smear and material samples showed detectable activity, the SEB was assigned the default radionuclide mixture and DCGL for the PBRF structures. For the SEB, only the Cold Pipe Tunnel was assigned a location-specific radionuclide mixture and DCGL.

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Plum Brook Reactor Facility FSSR Attachment 2, Rev. I Table 3 Note:

1. The scan investigation levels shown above are as listed in the FSS Plan. However, as described in Section 4.4 for Class I survey units, the scan investigation level was set to be equal to the DCGLw.

4.2 SEB Area Classification and Survey Unit Breakdown The SEB was divided into 39 areas for division into potential survey units and assigned initial MARSSIM classifications in the FSS Plan. This breakdown is shown in Table 2-1 of the FSS Plan. As part of the FSS implementation process, individual survey units are identified and their final MARSSIM classification established. The SEB was divided into 52 survey units for the FSS. Table 4 lists the individual survey units and their classification for the FSS. The table compares final classification of the survey units with FSS Plan Table 2-1 classifications.

Table 5 summarizes the survey unit breakdown by major elevation. Table 6 shows the survey unit breakdown by MARSSIM classification.

Table 4 was reviewed to ensure that no areas were classified "downward" from classifications assigned in the FSS Plan. It is seen from examination of the table that upward classification of two survey units did occur. The two survey units that were identified as having the FSS classification change upward were survey units SE-3-32 and SE-3-34. These two survey units were identified in the FSSP as being Class 3 areas. However, due to leaks in the CPT that eventually accumulated in the sump, located in SE-3-34, it was necessary to raise the classification for SE-3-34 to Class 1. Due to the proximity of survey unit SE-3-32 to SE-3-34 (now a class I area), it was also necessary to raise SE-3-32 to a Class 2 area.

Recent photographs, taken during survey unit inspections, are provided in Exhibits 8 through 29 of Appendix A.

Table 4, SEB Survey Units for FSS Surve Description FSSP Unit ) Class (Rm=Room; FI=Floor; Lw=Lower wall; Classification Uw=Upper wall; WI=Window ledges) (2)

SE-I-1 I Shop and Equipment Room Fl I SE-1-2 I Shop and Equipment Room F1 I SE-1-3 I Shop and Equipment Room F1 I SE-1-4 1 Shop and Equipment Building North and East Lw I SE-1-5 1 Shop and Equipment Building South and West Lw 1 SE-1-6 I Shop and Equipment Building Steel below 2m Lw I SE-1-7 2 North Class 2 Floors Fl 2 SE-1-8 2 South Class 2 Floors F1 2 SE-1-9 2 Class 2 Lower Walls Lw 2 SE-I-10 2 Class 2 Steel below 2m Lw 2 SE-I-I 1 3 Class 3 Upper Walls and Ceiling Uw, Ceiling 3 SE-1-12 3 Class 3 Steel Beams Uw, Ceiling 3 SE-2-1 I Rm 19A, Chemical Storage F1l SE-2-2 I Rm 19A, Chemical Storage Lw I SE-2-3 2 Mezzanine Class 2 areas, F1, Lw, Uw, Ceiling 2 SE-2-4 3 Mezzanine Class 3 areas, F1, Lw, Uw, Ceiling 3 SE-3-1 I Cold Pipe Tunnel - Floor Section 1 F1 I 12

Plum Brook Reactor Facility FSSR Attachment 2, Rev. 1 Table 4, SEB Survey Units for FSS Description FSSP Surve Unit (~

Surni Class (Rm=Room; FI=Floor; Lw=Lower - wall; Classification 2

Uw=Upper wall; WI=Window ledges) (2)

SE-3-2 I Cold Pipe Tunnel - Floor Section 2 Fl I SE-3-3 I Cold Pipe Tunnel - Floor Section 3 Fl 1 SE-3-4 1 Cold Pipe Tunnel - Floor Section 4 Fl I SE-3-5 I Cold Pipe Tunnel - Floor Section 5 Fl I SE-3-6 I Cold Pipe Tunnel - Floor Section6 Fl I SE-3-7 I Cold Pipe Tunnel - Floor Section 7 F1 I SE-3-8 I Cold Pipe Tunnel - Floor Section 8 FI I SE-3-9 I Cold Pipe Tunnel - North Wall Section 1 Lw, Uw I SE-3-10 I Cold Pipe Tunnel - North Wall Section 2 Lw, Uw 1 SE-3-11 I Cold Pipe Tunnel - North Wall Section 3 Lw, Uw I SE-3-12 I Cold Pipe Tunnel - North Wall Section 4 Lw, Uw I SE-3-13 1 Cold Pipe Tunnel - North Wall Section 5 Lw, Uw I SE-3-14 I Cold Pipe Tunnel - South Wall Section ! Lw, Uw I SE-3-15 I Cold Pipe Tunnel - South Wall Section 2 Lw, Uw I SE-3-16 I Cold Pipe Tunnel - South Wall Section 3 Lw, Uw I SE-3-17 I Cold Pipe Tunnel - South Wall Section 4 Lw, Uw I SE-3-18 I Cold Pipe Tunnel - South Wall Section 5 Lw, Uw 1 SE-3-19 I Cold Pipe Tunnel - Ceiling Section 1Ceiling I SE-3-20 I Cold Pipe Tunnel - Ceiling Section 2 Ceiling I SE-3-21 I Cold Pipe Tunnel - Ceiling Section 3 Ceiling I SE-3-22 I Cold Pipe Tunnel - Ceiling Section 4 Ceiling I SE-3-23 1 Cold Pipe Tunnel - Ceiling Section 5 Ceiling I SE-3-24 1 Cold Pipe Tunnel - Ceiling Section 6 Ceiling I SE-3-25 1 Cold Pipe Tunnel - Ceiling Section 7 Ceiling I SE-3-26 I Cold Pipe Tunnel - Cooling Tower Basin Tunnel Floor Fl I SE-3-27 Cold Pipe Tunnel - Cooling Tower Basin Tunnel South and West I Walls Lw, Uw SE-3-28 Cold Pipe Tunnel - Cooling Tower Basin Tunnel North and East 1 Walls Lw, Uw SE-3-29 1 Cold Pipe Tunnel - Cooling Tower Basin Tunnel Ceiling I 1 Cold Pipe Tunnel - Connecting Tunnel C Floor and Ceiling Fl, I SE-3-30 Ceiling SE-3-31 I Cold Pipe Tunnel - Connecting Tunnel C Walls Lw, Uw I SE-3-32 2 Basement Class 2 Areas Fl, Lw 3 SE-3-33 3 Basement Class 3 Areas Fl, Lw, Uw, Ceiling 3 SE-3-34 1 Rm 20/21 Sump #4 3 SE-4-1 2 Roof 2 SE-4-2 3 Exterior Walls 3 Table 4 Notes:

1. The increase from 39 areas identified in Table 2-1 of the FSS Plan to 52 survey units was primarily due to the redistribution of the 6 Cold Pipe Tunnel areas into 31 Class 1 survey units (Survey Unit classification-based size limits were maintained in accordance with FSS Plan).

2. The FSS Plan classifications were based on area history and available characterization data.

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Plum Brook Reactor Facility FSSR Attachment 2, Rev. 1 Table 5, SEB Survey Unit Breakdown Major No. of Surface  % of  % of Surface Elevation or Survey Area Survey Area Area Units (2 Units Shop Shop and and 6 419 11.5 2.4 Equipment Rm Ground Floor 6 8,358 11.5 47.4 Elevation Mezzanine(s) 4 1273 7.7 7.2 Basement 3 2168 5.8 12.3 CPT 31 2548 59.6 14.4 OW&R 2 2877 3.9 16.3 Total 52 17643 100 100 Table 5 Notes:

1. Rm-Room

2. OW&R - Outside Walls and Roof.

Table 6, SEB Survey Unit Breakdown by MARSSIM Classification Average No. Surface  % of  % of Area of Class Survey Area Survey Surface Survey Units (in2) Units Area Units M2) 1 39 3073 75 17.4 78.8 2 6 5155 11.5 29.2 859.2 3 7 9415 13.5 53.4 1345.0 Total 52 17643 100 100 4.3 Number of Measurements and Samples The number of measurements and samples for each SEB survey unit was determined using the MARSSIM statistical hypothesis testing framework as outlined in the FSS Plan. The sign test is selected because background count rates of instruments to be used are equivalent to a 14

Plum Brook Reactor Facility FSSR Attachment 2, Rev. I small fraction of the applicable DCGLw. 6 Decision error probabilities for the Sign Test are set at a = 0.05 (Type I error) and P3 = 0.10 (Type II error) in accordance with the FSSP.

The Visual Sample Plan (VSP) software was used to determine the number of FSS measurements in the SEB. 7 When the Sign Test is selected, the VSP software uses MARSSIM Equation 5-2 to calculate the number of measurements. Equation 5-2 is shown below:

NU=1.2* (ZI-a + Zl-f, )2 (D 1.

4 *[i{~ 0 .5]2 (Equation 1)

Where:

1.2 = adjustment factor to add 20% to the calculated number of samples, per a MARSSIM requirement to provide a margin for measurement sufficiency, N = Number of measurements or samples, a = the type I error probability, 03= the type II error probability, ZI. = proportion of standard normal distribution < I - a (1.6449 for a =

0.05),

Zi-p = proportion of standard normal distribution < I - 03(1.2816 for 1= 0.1),

(D(A/at) = value of cumulative standard normal distribution over the interval -

00, A/o, A = the "relative shift", defined as the DCGL - the Lower Bound of the Gray Region (LBGR), and at = the standard deviation of residual contamination in the area to be surveyed (or a similar area). This may include the variation in measured "ambient" background plus the material background (for total surface beta measurements).

The MARSSIM module of VSP requires user inputs for the following parameters: a, I3,A, a and the DCGLW. The number of measurements, N, for the 52 SEB survey units were calculated in 11 survey designs. Table 7 summarizes the SEB survey design calculations and lists the values of the key VSP input parameters.

Appendix B provides VSP maps of all sample measurement locations for each of the 52 survey units within the SEB.

6 Background count rates for the LMI 44-116 detector, the instrument of choice for FSS surface beta activity measurements on structures, are in the range of 300 cpm or less for most materials. This is equivalent to about 2500 dpm/100-cm 2 or less than 10% of PBRF structure DCGLs (this assumes a detection efficiency of - 12%).

7 The FSS Plan (Section 5.2.4) states that a qualified software product, such as Visual Sample Plan0 [PNL 2010], may be used in the survey design process.

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Plum Brook Reactor Facility FSSR Attachment 2, Rev. 1 Table 7, SEB Survey Design Summary Design S DCGL LBGR (2) C (2)

No. Survey Units Class (2) (2) A A/t N SE-1-6 through SE-1-1 1 27,166 26,137 1,029 343 3.0 11 SE- 1-7 through SE-I1-10 2 27,166 26,137 1,029 343 3.0 11 13 (3) 12 3 27,166 26,054 1,112 371 3.0 11 14 SE-2-1 & SE-2-2 1 27,166 23,341 3,825 1,275 3.0 11 15 (3) SE-2-3 2 27,166 23,341 3,825 1,275 3.0 11 16 (3) SE-2-4 3 27,166 23,341 3,825 1,275 3.0 11 10(4) SE-3-1 through 10 SE-3-31 1 11,000 7,660 3,340 1,113 3.0 11 17 (5) SE-3-32 2 26,079 20,631 5,448 1,454 3.7 11 18 (5) SE-3-33 3 26,079 20,631 5,448 1,454 3.7 11 21 (6) SE-3-34 1 10,560 6,199 4,361 1,454 3.0 11 36(7) SE-4-1 & SE-4-2 2,3 24449 12,225 12,224 4,890 2.5 11 Table 7 Notes:

1. The data reported in Table 7 is taken from the Survey Design reports listed. They are maintained in the PBRF Document Control System.

2. Units are dpm/100-cm 2.

3. No embedded piping was identified in these survey designs, so no adjustment to the DCGL was made for embedded piping. Also, no adjustment was made for the dose contribution from deselected radionuclides.

The survey units in these designs are evaluated for the dose contribution from deselected radionuclides in Section 5.2.

4. No embedded piping was identified in Design No. 10 and no adjustment to the DCGL was made for embedded piping or for deselected radionuclides. However, the Cold Pipe Tunnel (CPT) does contain embedded piping. The conservative assumption is made that all the CPT structure survey units are impacted by embedded piping. The survey units in this design are evaluated for the dose contribution from embedded piping and deselected radionuclides in Section 5.2.

5. The DCGLs in these survey designs were adjusted for embedded piping, but were not adjusted for deselected radionuclides. The survey units in these designs are evaluated for the dose contribution from deselected radionuclides in Section 5.2.

6. Survey design inputs for the SEB Basement Sump #4 (Design No.21, SE-3-34) were derived from DCGLs for the Cold Pipe Tunnel (CPT) since it was determined that Sump #4 was a collection point for CPT floor drainis. The Design No. 21 DCGLw, 10,560 dpm/100-cm 2, was obtained by adjusting CPT DCGL, 11,000 dpm/1 00-cm 2, by a factor of 24/25 to account for embedded piping. The survey unit in this design is evaluated for the contribution from deselected radionuclides in Section 5.2.

7. In Survey Design No. 36, survey units SE-4-1 and SE-4-2 (building exterior surfaces), the DCGLw, 24,449 dpm/1 00-cm2, was obtained by adjusting the default value, 27,166 dpm/100-cm 2 , by a factor of 22.5/25 to account for deselected "insignificant" radionuclides. No embedded pipe is associated with this design.

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Plum Brook Reactor Facility FSSR Attachment 2, Rev. 1 Selection of design input parameters followed guidance in the FSS Plan. The Plan states that "the LBGR is initially set at 0.5 times the DCGLw, but may be adjusted to obtain a value for the relative shift (A/c) between 1 and 3." It is seen in Table 7, that in the majority of SEB designs, a relative shift value of 3.0 was used in the final calculations for determining N.

The VSP software automatically performs an analysis to examine the sensitivity of N, the number of samples, to critical input parameters. The following is an example obtained from the VSP report for survey unit SE-2-1 in Design No. 14. The sensitivity the of number of samples was explored by varying the following parameters: standard deviation, lower bound of gray region (as % of DCGL), beta, probability of mistakenly concluding that the survey unit mean concentration, p, is greater than the DCGL and alpha, probability of mistakenly concluding that the survey unit mean concentration, p, is less than the DCGL. Table 8 summarizes this analysis. The region of critical sensitivity is for a = 0.05 (required), 03= 0.10 (optional) and the LBGR set equal to 90% of the DCGL. In this region, N is only moderately sensitive to an increase of 100% in the value of a. In this case N changes from 11 to 12. The sensitivity of N to an incorrect conclusion that the survey unit will pass (regulator's risk) is quite low; increasing a from 0.05 to 0.10 and 0.15 shows that the number of measurements is 11 or fewer in all cases except one. These results show that N = 1 represents a conservative design.

Table 8, VSP Sensitivity Analysis Results for Survey Unit SE-2-1 Design Number of Samples DCGL=27166 a=0.05(2 ) a =0.10 a =0.15 a'=1452(_)(3) a=726 a=1452 (v=726 o"=1452 c=726 LBGR=90% '(4) P=0.05 (5, 16 14 12 11 11 10 P3=0.10 12 11 10 9 9 8 03=0.15 11 10 9 8 6 6 LBGR=80% P3=0.05 14 14 11 11 10 10 P3=0.10 11 11 9 9 8: 8 13=0.15 10 10 8 8 6 6 LBGR=70% 13=0.5 14 14 11 11 10 10 13=0.10 11 11 9 9 8 8 13=0.15 10 10 8 8 6 6 Table 8 Notes:

1. Units of DCGL, 0 and LBGR are dpm/100 -cm 2.

2. a = Alpha (%), Probability of mistakenly concluding that p < DCGL.

3. a = Standard Deviation.

4. LBGR = Lower Bound of Gray Region (as % of DCGL).

5. P3= Beta (%), Probability of mistakenly concluding that p > DCGL Visual Sample Plan was also used to determine the grid size, the random starting location coordinates (for Class I and 2 survey units) and to display the measurement locations on survey unit maps drawn to scale. Refer to Appendix B for location coordinate tables and scale VSP maps showing measurement locations for each SEB survey unit.

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Plum Brook Reactor Facility FSSR Attachment 2, Rev. 1 The survey designs also specify scan survey coverage and action levels based on the MARSSIM classification listed in Table 4. If the scan sensitivity of the detectors used in Class I survey units is below the DCGLw, the number of measurements in each survey unit is determined solely by the Sign Test. If the scan sensitivity is not below the DCGLw, the number of measurements is increased as determined by the Elevated Measurement Test. As discussed in the next section, the scan sensitivities of instruments used in the FSS of the SEB are below the DCGLw, and no increase in the number of measurements calculated using the Sign Test was required. One exception would be the LMI 44-9. As observed in Table 9, the scan sensitivity for the LMI 44-9 is 22,659 dpm/100-cm2, which is greater than the DCGL for the CPT (11,000 dpm/100-cm 2). However, the primary use for the LMI 44-9 was to determine the activity in "hard-to-reach" places inaccessible to the LMI 44-116.

4.4 Instrumentation and Measurement Sensitivity Instruments to be used in the FSS of each survey unit are selected in each survey design.

Their detection sensitivities must be sufficient to meet the required action levels for the MARSSIM class of each survey unit. Minimum detection sensitivities for static alpha and beta measurements are calculated using the following equation:

3 +3.29 BR *tt*(1'+t)

MDCstatic = (Equation 2) t*

• E~ *-

100 Where:

MDCstatic = Minimum Detectable Concentration (dpm/100-cm 2),

BR = Background Count Rate (cpm),

tb = Background Count Time (min),

t, = Sample Count Time (min),

A = Detector Open Area (cm 2) and Eot = Total Detection Efficiency (counts per disintegration). The total efficiency equals the product of Detector Efficiency, Ei and Surface Efficiency, E,.

Scan sensitivities for detectors which measure alpha and beta surface activity are determined using the following equation:

d'* @-

• 60 MDCscan = ' (Equation 3)

Ei* Es * *P*10 100 Where:

MDCsca, = Minimum Detectable Concentration (dpm/1 00-cm 2),

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Plum Brook Reactor Facility FSSR Attachment 2, Rev. 1 d' = Index of sensitivity related to the detection decision error rate of the surveyor, from Table 6.5 of MARSSIM [USNRC 2000],

i = observation counting interval, detector width (cm) / scan speed (s),

bi = background counts per observation interval, Ei = Detector Efficiency (counts per disintegration),

Es = Surface Efficiency, typically 25% for alpha and 50% for beta (ISO 7503-1, Table 2 [ISO 1988],

p = Surveyor efficiency (typically 50%) and A = Detector Open Area (cm 2).

A summary of the a priori detection sensitivities of instruments used in the FSS of the SEB is provided in Table 9.

Table 9, Detection Sensitivities of Field Instruments Detector MDCscan Net cpm Detector Model Efficiency (dpm/100- Equivalent MDCstatic (c/d) (') cm) to MDCscan (dpm/100-cm2)

LMI 44-116 3( ) (4) 0.12 2402 172 452 LMI 43-37 5 ) 0.145 798 352 NA LMI 44_9(6) 0.0925 22,659 151 4,745 Table 9 Notes:

1. The detector efficiencies listed are total efficiency, i. e., E, = E, + E,.

2. A priori scan sensitivities for the LMI 44-116 & LMI 43-37 detectors are calculated using Equation 3.

3. The static MDC for the LMI 44-116 detector is calculated using Equation 2 with background count rate = 196 cpm, E, = 0.242 and E, = 0.5 (detector-to-surface distance = 0.5 in.)

4. The scan MDC for the LMI 44-116 is from Survey Design No.11 Att. 5-2. The background count rate is 196 cpm; scan speed is 10 cm/s, Ej = 0.242, E, = 0.5, efficiency correction factor = 0.8349 to compensate for concrete roughness (detector-to-surface distance 0.5 in.)

5. The scan MDC for the LMI 43-37 is from Survey Design No. 11, Att. 5-3. The background count rate is 483 cpm; scan speed is 30 cm/s, E, = 0.29, E, = 0.5, detector-to-surface distance 0.5 in.

6. The static MDC for the LMI 44-9 detector is calculated using Equation 2 with background count rate = 200 cpm, Ej = 0.185 and E, = 0.5 (detector-to-surface distance = 0.5 in.)

The scan investigation level for Class 1 survey units listed in Table 3 is the DCGLEMC, as specified in the FSS Plan Section 8.1. However, the scan investigation level is actually set at the DCGLw established in the survey design for each structure survey unit. This practice was established in early survey designs for conservatism and was continued in subsequent designs.

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Plum Brook Reactor Facility FSSR Attachment 2, Rev. I It is also noted the FSS Plan states that technicians are to respond to indications of increased count rates even though scan count rates may not be above the investigation level specified in survey instructions. 8 Modifications to survey instructions are adjusted to account for unusual measurement conditions. Modified detection sensitivities may be applied taking into account adjustments in detector efficiency. Scan speeds may be reduced to ensure that required scan sensitivities are achieved. The bases for adjustments due to non-standard conditions are provided in PBRF Technical Basis Documents. Examples of areas or locations in SEB survey units where special measurement conditions apply are shown in Exhibits 26 and 27 of Appendix A.

5.0 SEB Survey Results Results of the SEB FSS are presented in this section. This includes scan survey frequencies (% of areas covered) for each survey unit and occurrence of events where scan investigation levels were exceeded. Investigations performed and the results are summarized. Fixed measurement results for each survey unit and the results of comparison tests of survey unit maximum and average values with the DCGLw are reported. As discussed below, no statistical tests were required. It is shown that

-levels of residual contamination have been reduced to levels that are ALARA. This section closes with a summary which concludes that applicable criteria for release of the SEB for unrestricted use are satisfied and all FSS Plan requirements are met.

5.1 Surveys and Investigations Scan survey results were reviewed to confirm that the scan coverage requirement (as % of survey unit area) was satisfied for all survey units. The results of QC replicate surveys were also reviewed to confirm that the minimum coverage requirement of 5% was satisfied. Results of the SEB scan surveys are compiled in Table 10. The table shows that scan coverage requirements were satisfied for all survey units. The table also shows that scan investigation levels were exceeded in three survey units (all Class 1). The results of the investigations are summarized below.

8 From FSS Plan Section 7.1.1: "Technicians will respond to indications of elevated areas while surveying. Upon detecting an increase in visual or audible response, the technician will reduce the scan speed or pause and attempt to isolate the elevated area. If the elevated activity is verified to exceed the established investigation level, the area is bounded (e.g., marked and measured to obtain an estimated affected surface area). Representative static measurements are obtained as determined by the FSS/Characterization Engineer. The collected data is documented on a Radiological Survey Form."

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Plum Brook Reactor Facility FSSR Attachment 2, Rev. I Table 10, Scan Survey Results Scan Survey QC Replicate Investigation Survey Class Coverage (%) Scan Coverage Level Unit () (%) (1)(2) (3) Exceeded SE-i-1 1 100 7 No SE-1-2 1 100 7 No SE- 1-3 1 100 7 No SE-1-4 1 100 7 No SE-1-5 1 100 7 No SE-1-6 1 100 7 No SE-1-7 2 52 9 No SE-1-8 2 52 9 No SE-1-9 2 51 9 No SE-I-10 2 57 12 No SE-I-11 3 11 6 No SE-1-12 3 11 6 No SE-2-1 1 100 10 No SE-2-2 1 100 10 No SE-2-3 2 60 6 No SE-2-4 3 13 5 No SE-3-1 1 100 33 Yes SE-3-2 1 100 33 Yes SE-3-3 1 100 33 No SE-3-4 1 100 33 No SE-3-5 1 100 33 No SE-3-6 1 100 33 No SE-3-7 1 100 11 No SE-3-8 1 100 17 No SE-3-9 1 100 7 No SE-3-10 1 100 7 No SE-3-11 1 100 7 No SE-3-12 1 100 7 No SE-3-13 1 100 7 No SE-3-14 1 100 7 No SE-3-15 1 100 7 No SE-3-16 1 100 7 No SE-3-17 1 100 7 No SE-3-18 1 100 7 No SE-3-19 1 100 6 Yes SE-3-20 1 100 6 No SE-3-21 1 100 6 No SE-3-22 1 100 6 No SE-3-23 1 100 6 No SE-3-24 1 100 6 No SE-3-25 1 100 7 No SE-3-26 1 100 7 No SE-3-27 1 100 7 No SE-3-28 I 100 7 No SE-3-29 1 100 7 No 21

Plum Brook Reactor Facility FSSR Attachment 2, Rev. 1 Table 10, Scan Survey Results Scan Survey QC Replicate Investigation Survey Class Coverage (%) Scan Coverage Level Unit (1) (%) (1)(2) (3) Exceeded SE-3-30 1 100 7 No SE-3-31 1 100 7 No SE-3-32 2 53 6 No SE-3-33 3 10 10 No SE-3-34 1 100 5 No SE-4-1 2 51 6 No SE-4-2 3 10 7 No Table 10 Notes:

1. Scan coverage % results are rounded to the nearest whole per cent. Values reported with the first decimal as 5, e. g., 5.5, are rounded downward.

2. The % scan coverage is given as the % of the area scanned in the initial survey.

3. Replicate QC scan results are reported for multiple survey units in some survey request close-out reports. The QC scan percentages are reported as % of the scanned area of the survey units combined. So the same % scanned is assigned to all of the survey units.

Review of SEB release records indicates that during the FSS of the SEB, investigations were performed in three survey units.

In survey unit SE-3-1, Cold Pipe Tunnel, a Class 1 survey unit, three localized areas were investigated. The scan investigation level was exceeded at two locations and at a third location the technician initiated an investigation responding to an increase in count rate at a location of irregular geometry. The areas were bounded and investigations performed of each.

The three locations were found to contain fixed activity with measured gross surface activity of 8,320, 8,480 and 4,050 dpm/100-cm 2 respectively. These values are all below the DCGLw (11,000 dpm/1 00-cm 2), and no further action was required.

In survey unit SE-3-2, Cold Pipe Tunnel, a Class 1 survey unit, one small localized area was identified that exceeded the scan investigation level. The area was bounded and an investigation was performed. The area was observed to be approximately 4 cm 2 and the measured activity was 21,574 dpm/100-cm 2 . An evaluation was conducted and it was determined that this area would not contribute significantly to the annual dose from the survey unit based on the following:

" The measured activity is < DCGLEMC, 29,015 dpm/100-cm 2 (listed in Table 6 of the Survey Design 10 report).

" The measured activity is less than the investigational DCGLEMC of 442,200 dpm/100-cm 2 which was derived by using Table 3-5 of the FSSP and applying an area factor of 40.2.

• The elevated measurement test was performed using the following equation, in accordance with procedure CS-09, Section 4.6. The calculated unity value was 0.113.

22

Plum Brook Reactor Facility FSSR Attachment 2, Rev. 1 J (averageconcentration in elevated area -3) _ 1.0 DCGLw (Area Factor)(LDCGLw) 6 = the average residual activity in the survey unit In survey unit SE-3-19, Cold Pipe Tunnel, a Class 1 survey unit, one small localized area was identified that exceeded the scan investigation level. The area was bounded and an investigation was performed. The area was observed to be approximately 125 cm2 and the measured activity was 12,709 dpm/100-cm 2. An evaluation was conducted and it was determined that this area would not contribute significantly to the annual dose of the survey unit based on the following:

" The measured activity is < DCGLEMC, 24,338 dpm/100-cm 2 (listed in Table 6 of the Survey Design 10 report).

• The measured activity is less than the investigational DCGLEMC of 442,200 dpm/100-cm2, which was derived by using Table 3-5 of the FSSP and applying an area factor of 40.2.

• The elevated measurement test was performed using the following equation, in accordance with procedure CS-09, Section 4.6. The calculated unity value was 0.08.

+ (average concentration in elevated area - 5) < 1.0 DCGLw (Area Factor)(DCGLw) 6 = the average residual activity in the survey unit As all three of these survey units were Class 1, no reclassification was required as a result of these investigations.

5.2 Fixed Measurements and Tests Results of the assessment of SEB FSS measurements are presented in Table 11 (individual measurements in each survey unit are reported in Appendix B). Table 11 compares the maximum activity measured in each survey unit to the DCGL. The mean activity of each survey unit is also compared to the DCGL, and as expected, are all less than the DCGL. The DCGL values used for these comparisons are identified as "adjusted DCGLs". As explained in the Table 11 Notes, the adjusted DCGLs are calculated for each survey unit to allow for the dose contribution from deselected radionuclides (2.5 mrem/y) and embedded piping (1 mrem/y) as applicable. The last column of Table 11 shows the results of an additional check.

This check is to ensure that the dose from residual surface contamination in each survey unit plus the doses allocated for embedded piping and deselected radionuclides is below 25 mrem/y.

23

Plum Brook Reactor Facility FSSR Attachment 2, Rev. 1 These evaluations show that the doses from the SEB survey units are well below the 25 mrem/y criterion. 9 The average of 579 systematic total surface beta measurements reported in the SEB release records is: 494 +/- 258 dpm/1 00-cm 2 (one standard deviation).

Removable surface activity measurements were also performed at each fixed activity measurement location and counted for gross alpha and gross beta activity. A review of the SEB Release records was conducted to ensure that all smear counting results were less than 10% of the gross activity DCGL. The requirement for PBRF laboratory smear counting instruments isthat the MDAs be < 10% of the applicable gross activity DCGL 10 . Gross beta and gross alpha counts for all SEB smears were less than MDA.

Table 11, SEB Total Surface Beta. Activity Measurement Summary and Test Results Total Survey DCGLw. Adjusted Maximum Test Result Average Test Result Dose <

DCGL (2)(4) N (3) (4) Maximum < (4) Average < 25 Unit ID (1) (4)

Adj. DCGL Adj. DCGL mrem/y (5)

SE-I-1 27,166 24,449 11 757 Yes 547 Yes Yes SE- 1-2 27,166 24,449 11 951 Yes 624 Yes Yes SE-1-3 27,166 24,449 11 826 Yes 657 Yes Yes SE-1-4 27,166 24,449 11 174 Yes 36 Yes Yes SE-1-5 27,166 24,449 11 285 Yes 68 Yes Yes SE-1-6 27,166 24,449 11 194 Yes 24 Yes Yes SE-1-7 27,166 24,449 11 719 Yes 493 Yes Yes SE-1-8 27,166 24,449 11 934 Yes 686 Yes Yes SE-1-9 27,166 24,449 13 566 Yes 201 Yes Yes SE-I-10 27,166 24,449 11 230 Yes 77 Yes Yes SE-1-11 27,166 24,449 11 444 Yes 42 Yes Yes SE-1-12 27,166 24,449 11 221 Yes 36 Yes Yes SE-2-1 27,166 24,449 12 867 Yes 704 Yes Yes SE-2-2 27,166 24,449 11 371 Yes 41 Yes Yes 9 The average estimated dose from residual activity in the SEB structure survey units is 1.2 mrem/y and the maximum dose is 4.5 mrem/y. Included in this average are the estimated doses from each survey unit obtained from the systematic total surface beta measurements taken on the structure surfaces and the contributions from measured activity in localized areas of elevated activity. For the systematic measurements, the estimated dose is obtained as the ratio of the survey unit average residual surface beta activity (from the systematic measurements only) to the adjusted DCGL times the dose that is equivalent to the adjusted DCGL. The dose contribution from localized areas of elevated activity is estimated to be 2.83 mremly for survey unit SE-3-2 and 1.89 mrem/y for survey unit SE-3-19. The dose contribution from localized areas of elevated area activity is estimated using the elevated measurement test unity value formula shown in Section 5.1.

10 Typical MDAs for PBRF low background smear counting instruments are 14 dpm for alpha and 18 dpm for beta.

Smears cover 100 cm2, so these MDA values are equivalent to dpm/I00-cm 2 .

24

Plum Brook Reactor Facility FSSR Attachment 2, Rev. 1 Table 11, SEB Total Surface Beta Activity Measurement Summary and Test Results Total DCGLw Adjusted Maximum Average Test Result Dose <

Survey (3)

Unit ID (1) (4) DCGL (2)(4) (4) Maximum < (4) Average < 25 Adj. DCGL Adj. DCGL mrem/y (5)

SE-2-3 27,166 24,449 11 534 Yes 171 Yes Yes SE-2-4 27,166 24,449 11 669 Yes 248 Yes Yes SE-3-1 11,000 9,460 11 2688 Yes 1186 Yes Yes SE-3-2 11,000 9,460 11 1115 Yes 726 Yes Yes (6)

SE-3-3 11,000 9,460 11 777 Yes 540 Yes Yes SE-3-4 11,000 9,460 11 1210 Yes 784 Yes Yes SE-3-5 11,000 9,460 11 796 Yes 593 Yes Yes SE-3-6 11,000 9,460 11 921 Yes 753 Yes Yes SE-3-7 11,000 9,460 11 742 Yes 458 Yes Yes SE-3-8 11,000 9,460 13 808 Yes 634 Yes Yes SE-3-9 11,000 9,460 11 859 Yes 587 Yes Yes SE-3-10 11,000 9,460 11 834 Yes 553 Yes Yes SE-3-11 11,000 9,460 11 1060 Yes 582 Yes Yes SE-3-12 11,000 9,460 13 893 Yes 590 Yes Yes SE-3-13 11,000 9,460 11 819 Yes 623 Yes Yes SE-3-14 11,000 9,460 11 711 Yes 479 Yes Yes SE-3-15 11,000 9,460 11 861 Yes 648 Yes Yes SE-3-16 11,000 9,460 11 1060 Yes 659 Yes Yes SE-3-17 11,000 9,460 11 881 Yes 558 Yes Yes SE-3-18 11,000 9,460 11 636 Yes 456 Yes Yes SE-3-19 11,000 9,460 11 782 Yes 529 Yes Yes 6 )

SE-3-20 11,000 9,460 11 1415 Yes 628 Yes Yes SE-3-21 11,000 9,460 11 796 Yes 600 Yes Yes SE-3-22 11,000 9,460 11 676 Yes 484 Yes Yes SE-3-23 11,000 9,460 11 634 Yes 364 Yes Yes SE-3-24 11,000 9,460 11 715 Yes 513 Yes Yes SE-3-25 11,000 9,460 11 841 Yes 587 Yes Yes SE-3-26 11,000 9,460 11 991 Yes 718 Yes Yes SE-3-27 11,000 9,460 *11 1000 Yes 673 Yes Yes SE-3-28 11,000 9,460 11 1106 Yes 738 Yes Yes SE-3-29 11,000 9,460 11 1188 Yes 946 Yes Yes 25

Plum Brook Reactor Facility FSSR Attachment 2, Rev. 1 Table 11, SEB Total Surface Beta Activity Measurement Summary and Test Results Total DCGLw Adjusted (3) Maximum Test Result Average Test Result Dose <

Survey DCGL (2)(4) S Maximum < (4) Average < 25 Unit ID (1)(4) (4)

Adj. DCGL Adj. DCGL mrem/y (5)

SE-3-30 11,000 9,460 11 1097 Yes 671 Yes Yes SE-3-31 11,000 9,460 11 958 Yes 565 Yes Yes SE-3-32 27,166 23,363 11 1177 Yes 665 Yes Yes SE-3-33 27,166 23,363 11 538 Yes 393 Yes Yes SE-3-34 10,560 9,900 11 369 Yes 80 Yes Yes SE-4-1 24,449 24,449 11 642 Yes 159 Yes Yes SE-4-2 24,449 24,449 11 842 Yes 323 Yes Yes Table 11 Notes:

1. The DCGLw as specified in the survey design.

2. The DCGLw is adjusted by a factor of 21.5/25 to account for one mrem/y dose contribution from embedded piping and 2.5 mrem/y from deselected radionuclides. If no embedded piping is associated with the survey unit, the DCGLw is adjusted by a factor of 22.5/25 to account for the dose contribution from deselected radionuclides only.

3. N = number of measurements. Where the number of measurements is greater than the default design value of 11, it is due to the VSP method of fitting the calculated systematic grid pattern into the survey unit. On occasion, this adds additional measurement locations.

4. Units are dpm/100-cm2.

5. This column shows the results of a check performed on each survey unit to confirm that the building structure surface activity measured from the systematic measurements plus any activity in localized areas of elevated activity is less than the adjusted DCGL. This is an additional check to ensure that the total dose from all contributors associated with each survey unit is less than 25 mrem/y.

6. The dose estimated for survey units SE-3-2 and SE-3-19 in the CPT each include the contribution from a localized area of elevated activity estimated by applying the EMC unity value factor calculated in accordance with the FSS Plan Section 8.0.

5.3 ALARA Evaluation It is shown that residual contamination in the SEB has been reduced to levels that are ALARA, using a method acceptable to the NRC. The NRC guidance on determining that residual contamination levels are ALARA includes the following:

"In light of the conservatism in the building surface and surface soil generic screening levels developed by the NRC, NRC staff presumes, absent information to the contrary, those licensees who remediate building surfaces or soil to the generic screening levels do not need to provide analyses to demonstrate that these screening levels are ALARA. In addition, if residual radioactivity cannot be detected, it may be presumed 26

Plum Brook Reactor Facility FSSR Attachment 2, Rev. I that it had been reduced to levels that are ALARA. Therefore the licensee 1' may not need to conduct an explicit analysis to meet the ALARA requirement."

Screening level values published by the NRC for the mix of radionuclides in structural surface residual contamination potentially present in the SEB are shown in Table 12. Since individual radionuclide activity concentrations are not measured in the FSS of structures, a direct comparison of residual contamination levels to screening level values is not possible. A comparison can be made by converting the nuclide-specific screening level values to an appropriate gross activity DCGL. This is accomplished using activity fractions used in development of the SEB gross activity DCGL. A screening level value that is equivalent to the gross activity DCGL was calculated using the equations in Section 3.6 of the FSS Plan and the activity fractions listed in Table 2 (also shown in Table 12). The screening level equivalent DCGL for the SEB is 1,188 dpm/1 00-cm 2. This value was determined by using the most conservative screening value based in the two radionuclide mixtures for the SEB reported in Technical Basis Document PBRF-TBD-07-001 [PBRF 2007].

As reported in Section 5.2, the average total surface beta activity measured in the FSS of the SEB is 494 +/- 258 dpm/100-cm2 (one standard deviation). The upper limit of 9 5 th %

confidence interval of this mean value is 515 dpm/100-cm 2 .12 This value is well below the screening level gross activity DCGL of 1,188 dpm/1 00-cm2 .

Table 12, Screening Level Values for SEB and Radionuclide Activity Fractions Radionuclide Screening Level Value SEB Activity CPT Activity (d m/100-cm ) 2 Fraction (%) Fraction %

H-3 1.2 E+08 27 0 Co-60 7.1E+03 (1) 9.7 100 Sr-90 8.7E+03 { 7.9 0 1-129 3.5E+04( )1 1.4 0 Cs-137 2.8E+04 (1) 46.7 0 Eu-154 1.2E+04(2) 0.1 0 U-234 9.1E+01 (2) 7.0 0 U-235 9.8E+01 2 } 0.2 0 Table 12 Notes:

1. Values from NUREG-1757 Vol. 2, Table H.1 [USNRC 2006].

2. Values from NUREG/CR-5512, Vol. 3, Table 5.19 [SNL 1999]. These are 90 th percentile values of residual surface activity corresponding to 25 mrem/y to a future building occupant.

This guidance was initially published in Draft Regulatory Guide DG-4006, but has been reissued in NUREG-1757 Volume 2, Appendix N.

12 The upper limit of the confidence interval, 95h percentile value, is calculated as: UL = mean + 1.96 o/'in, where n =

579 measurements.

27

Plum Brook Reactor Facility FSSR Attachment 2, Rev. 1 5.4 Comparison with EPA Trigger Levels The PBRF license termination process includes a review of residual contamination levels in groundwater and soil, as applicable, in accordance with the October 2002 Memorandum of Understanding (MOU) between the US NRC and the US Environmental Protection Agency (EPA) [USEPA 2002]. Concentrations of individual radionuclides, identified as "trigger levels" for further review and consultation between the agencies, are published in the MOU.

The trigger levels applicable to the PBRF are residual soil concentrations in excess of:

• Co-60, 4 pCi/g,

" Sr-90 (+Daughters), 23 pCi/g, and

" Cs-137 (+Daughters), 6 pCi/g.

No soil or groundwater samples were collected or analyzed as part of this Service and Equipment Building Final Status Survey Report.

5.5 Conclusions The results presented above demonstrate that the SEB satisfies all FSS Plan commitments and meets the release criteria in 10CFR20 Subpart E. The principal conclusions are:

• Scan surveys were performed in all 52 SEB survey units with scan coverage either equal to (for Class 1) or in excess of the percentage coverage requirements (for Class 2 and 3) for the survey units.

• Residual surface contamination above investigation levels was detected in only three of 52 survey units. Investigations were performed on the areas and they were below the applicable DCGLEMc and determined to not contribute significantly to the dose for each survey unit.

• Except as noted above, all remaining total surface activity measurements are less than the applicable DCGLW, 11,000 or 27,166 dpm/100-cm2.2

• All survey unit mean fixed measurement results (total surface beta activity) are below the DCGLw, hence no statistical tests were required.

" All removable surface activity measurements are less than 10% of the DCGLw.

" Residual surface activity concentration measurement results were compared to NRC screening level values - demonstrating that the ALARA criterion is satisfied.

• Only minor changes from what was proposed in the FSS Plan were made - the classification of two survey units was increased above what was proposed in the Plan.

• There were no changes from initial assumptions (in the FSS Plan) regarding the extent of residual activity in the SEB. Only two measurements in excess of the DCGL occurred (both in Class I survey units) and no reclassification of survey units was required as a result of FSS measurements and investigations.

28

Plum Brook Reactor Facility FSSR Attachment 2, Rev. 1 6.0 References ISO 1988 International Organization for Standardization, Evaluation of Surface Contamination,Part1. Beta Emitters andAlpha Emitters, ISO-7503-1, 1988.

NASA 2006 NASA Safety and Mission Assurance Directorate, Plum Brook Reactor Facility, DecommissioningProjectQualityAssurance Plan, QA-0 1, Revision 2, February 2006.

NASA 2007 NASA Safety and Mission Assurance Directorate, FinalStatus Survey Planfor the Plum Brook Reactor Facility,Revision 1, February 2007.

NASA 2007a NASA Safety and Mission Assurance Directorate, DecommissioningPlanfor the Plum Brook Reactor Facility,Revision 6, July 2007.

PBRF 2007 Plum Brook Reactor Facility Technical Basis Document, Adjusted Gross DCGLsfor StructuralSurfaces, PBRF-TBD-07-001, June 2007.

PBRF 2007a Plum Brook Reactor Facility Technical Basis Document, Efficiency Correction Factor,PBRF-TBD-07-004, November 2007.

PBRF 2009 Plum Brook Reactor Facility, Memorandum to Project File, J. L. Crooks, Don Young, FSS FinalReport Background Information - SEB, Service Equipment Building (1131), December 7, 2009.

PBRF 2009a Plum Brook Reactor Facility Technical Basis Document, 44-10 Detector MDCscan Valuesfor Various Survey Conditions,PBRF-TBD-09-002, June 2009.

PBRF 2009b Plum Brook Reactor Facility Technical Basis Document, An Evaluation of the 2350-1/44-10 NaI Detector Response in Water Covered Areas, PBRF-TBD-09-006, October 2009.

PBRF 2010 Plum Brook Reactor Facility, Memorandum to Project File, Bruce Mann, EngineeringRecordfor FinalStatus Survey Report, Attachment 1 Calculations, March 25, 2010.

USNRC 2000 US Nuclear Regulatory Commission, Multi-Agency RadiationSurvey and Site Investigation Manual (MARSSIM), NUREG-1575, Rev. 1, August 2000.

USNRC 2006 US Nuclear Regulatory Commission, ConsolidatedDecommissioningGuidance, Characterization,Survey and Determinationof RadiologicalCriteria,NUREG 1757, Vol. 2, Rev. 1, September 2006.

PNL 2010 Battelle Pacific Northwest Laboratories (PNL), Visual sample Plan, Version 5.9, 2010.

29

Plum Brook Reactor Facility FSSR Attachment 2, Rev. 1 SNL 1999 Sandia National Laboratories (SNL), for US Nuclear Regulatory Commission, Residual Radioactive ContaminationFrom Decommissioning,ParameterAnalysis, NUREG/CR-5512, Vol.3, Oct. 1999.

USEPA 2002 Memorandum of Understanding, US Environmental Protection Agency and US Nuclear Regulatory Commission, Consultationand Finality on Decommissioning and Decontaminationof ContaminatedSites, October 9, 2002.

7.0 Appendices Appendix A - Exhibits Appendix B - Survey Unit Maps Showing Measurement Locations &

Fixed Measurement Data 30

Final Status Survey Report Attachment 2 Service Equipment Building (Building 1131)

Revision 0 Appendix A Exhibits

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, List of Exhibits Exhibit 1, Service and Equipment Building Viewed from the North West ....................................... 3 Exhibit 2, SEB Viewed from the North East Showing Rollup Doors ............................................... 4 Exhibit 3, Close up View of the SEB West Wing .............................................................................. 5 Exhibit 4, SEB First Floor Survey Units ............................................................................................ 6 Exhibit 5, SEB Second Floor Survey Units ...................................................................................... 7 Exhibit 6, SEB Basement/Cold Pipe Tunnel Survey Units ............................................................... 8 Exhibit 7, SEB Shop and Equipment Survey Unit ........................................................................... 10 Exhibit 8, SEB Basement Sumps 1 and 2 (Survey Unit SE-3-32) ....................................................... 11 Exhibit 9, SEB Basement Sump 3 (Survey Unit SE-3-32) ............................................................ 12 Exhibit 10, Views of SEB Boiler Room Drains and Floor Details (Survey Unit SE-1-7) ............... 13 Exhibit 11, Views of SEB Shop and Equipment Room (Survey Unit SE-I-1) ............................... 14 Exhibit 12, Views of SEB Shop Walls and Windows(Survey Unit SE-1-6) .................................. 15 Exhibit 13, Views of SEB First Floor Hallways (Survey Unit SE-1-7) .......................................... 16 Exhibit 14, SEB Boiler Room Floor Details (Survey Unit SE-1-7) ................................................. 17 Exhibit 15, Views of SEB Water Treatment Room (Survey Unit SE- 1-7) ..................................... 18 Exhibit 16, General Views of SEB Mezzanine (Survey Unit SE-2-2) ............................................ 19 Exhibit 17, SEB Mezzanine Room 14 Landing (Survey Unit SE-2-3) ............................................ 20 Exhibit 18, SEB Mezzanine (2 nd Fl.) Office Rooms (Survey Unit Se-2-4) .................................... 21 Exhibit 19, SEB Cold Pipe Tunnel Floor (Survey Unit SE-3-8) ..................................................... 22 Exhibit 20, Views of SEB Cold Pipe Tunnel Walls (Survey Unit SE-3-15) .................................. 23 Exhibit 21, Views of SEB Cold Pipe Tunnel Ceiling(Survey Unit SE-3-23) .................................. 24 Exhibit 22, Views of SEB Cooling Tower Basin Area of CPT (Survey Unit SE-3-26) ................. 25 Exhibit 23, Views of SEB Cooling Tower Basin CPT Walls (Survey Unit SE-3-28) .................... 26 Exhibit 24, Views of SEB CPT Connecting Tunnel (Survey Unit SE-3-30) ................................... 27 Exhibit 25, Views of SEB Basement (Survey Unit SE-3-32) ........................................................ 28 Exhibit 26, SEB Basement Stairwell (Survey Unit SE-3-32) .......................................................... 29 Exhibit 27, Views of SEB Roof (Survey Unit SE-4-1) .................................................................... 30 Exhibit 28, Views of Unusual Condition Measurement (UMC) Areas (Survey Unit SE-3-5) ..... 31 Exhibit 29, Views of Unusual Condition Measurement (UMC) Areas (Survey Unit SE-3-16) .......... 32 2

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 1, Service and Equipment Building Viewed from the North West 3

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 2, SEB Viewed from the North East Showing Rollup Doors 4

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 3, Close up View of the SEB West Wing 5

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 4, SEB First Floor Survey Units (T> qQ 4LS CLASS2 iCLASS 3

~1~ 6ýj U OPASD EGMET LRD

.: -0 A I SEB - FIRST FLOOR Survey Description FSSP Unit Class (Rm=Room; Fl=Floor; Lw=Lower wall; Classification Uw=Upper wall; Wl=Window ledges)

SE-I-1 I Shop and Equipment Room Fl I SE-1-2 1 Shop and Equipment Room Fl I SE-1-3 1 Shop and Equipment Room F I SE-1-4 I Shop and Equipment Building North and East Lw I SE-1-5 I Shop and Equipment Building South and West Lw I SE-1-6 1 Shop and Equipment Building Steel below 2m Lw I SE-1-7 2 North Class 2 Floors Fl 2 SE-1-8 2 South Class 2 Floors Fl 2 SE-1-9 2 Class 2 Lower Walls Lw 2 SE-I-10 2 Class 2 Steel below 2m Lw 2 SE-1-11 3 Class 3 Upper Walls and Ceiling Uw, Ceiling 3 SE-1-12 3 Class 3 Steel Beams Uw, Ceiling 3 6

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 5, SEB Second Floor Survey Units CLASS 1

- CLASS 2

- CLASS 3 1 3 T T 6 1

SEB - MEZZANINE FLOOR Survey Description FSSP Unit Class (Rm=Room; Fl=Floor; Lw=Lower wall; Classification Uw=Upper wall; WI=Window ledges)

SE-2-1 1 Rm 19A, Chemical Storage Fl I SE-2-2 1 Rm 19A, Chemical Storage Lw I SE-2-3 2 Mezzanine Class 2 areas, Fl, Lw, Uw, Ceiling 2 7

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 6, SEB Basement/Cold Pipe Tunnel Survey Units TI T

CLASS I I'

-CLASS 2

-CLASS 3 TUNNEL I

TUNNEL 218' TO REACTOR UTILITY TUNNEL 72' TO REACTOR COOLING BUILDING 1111 AREA 23 TOWER BUILDING 1152 SEB - BASEMENT Survey Unit summary for Basement/Cold Pipe Tunnel is continued on the next page.

8

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 6, SEB Basement/Cold Pipe Tunnel Survey Units (Continued)

Description FSSP Survey Unit ) Class (Rm=Room; FI=Floor; Lw=Lower wall; Classification Unit Uw=Upper wall; WI=Window ledges) (2) (3)

SE-3-1 I Cold Pipe Tunnel - Floor Section 1 Fl I SE-3-2 I Cold Pipe Tunnel - Floor Section 2 Fl I SE-3-3 1 Cold Pipe Tunnel - Floor Section 3 Fl I SE-3-4 1 Cold Pipe Tunnel - Floor Section 4 Fl I SE-3-5 1 Cold Pipe Tunnel -Floor Section 5 Fl I SE-3-6 1 Cold Pipe Tunnel -Floor Section 6 F1 I SE-3-7 I Cold Pipe Tunnel -Floor Section 7 Fl I SE-3-8 1 Cold Pipe Tunnel - Floor Section 8 F1 I SE-3-9 I Cold Pipe Tunnel -North Wall Section 1 Lw, Uw I SE-3-10 I Cold Pipe Tunnel -North Wall Section 2 Lw, Uw I SE-3-11 1 Cold Pipe Tunnel -North Wall Section 3 Lw, Uw I SE-3-12 I Cold Pipe Tunnel -North Wall Section 4 Lw, Uw I SE-3-13 I Cold Pipe Tunnel -North Wall Section 5 Lw, Uw I SE-3-14 I Cold Pipe Tunnel - South Wall Section 1 Lw, Uw I SE-3-15 1 Cold Pipe Tunnel - South Wall Section 2 Lw, Uw 1 SE-3-16 1 Cold Pipe Tunnel - South Wall Section 3 Lw, Uw I SE-3-17 1 Cold Pipe Tunnel - South Wall Section 4 Lw, Uw I SE-3-18 1 Cold Pipe Tunnel - South Wall Section 5 Lw, Uw I SE-3-19 1 Cold Pipe Tunnel - Ceiling Section lCeiling I SE-3-20 1 Cold Pipe Tunnel - Ceiling Section 2 Ceiling I SE-3-2 1 1 Cold Pipe Tunnel - Ceiling Section 3 Ceiling I SE-3-22 I Cold Pipe Tunnel - Ceiling Section 4 Ceiling I SE-3-23 I Cold Pipe Tunnel - Ceiling Section 5 Ceiling I SE-3-24 1 Cold Pipe Tunnel - Ceiling Section 6 Ceiling 1 SE-3-25 1 Cold Pipe Tunnel - Ceiling Section 7 Ceiling 1 SE-3-26 I Cold Pipe Tunnel - Cooling Tower Basin Tunnel Floor Fl 1 SE-3-27 I Cold Pipe Tunnel - Cooling Tower Basin Tunnel South and West I Walls Lw, Uw SE-3-28 I Cold Pipe Tunnel - Cooling Tower Basin Tunnel North and East Walls Lw, Uw SE-3-29 I Cold Pipe Tunnel - Cooling Tower Basin Tunnel Ceiling Ceiling I SE-3-30 1 Cold Pipe Tunnel - Connecting Tunnel C Floor and Ceiling FI, I Ceiling SE-3-3 1 1 Cold Pipe Tunnel - Connecting Tunnel C Walls Lw, Uw 1 SE-3-32 2 Basement Class 2 Areas FI, Lw 3 SE-3-33 3 Basement Class 3 Areas FI, Lw, Uw, Ceiling 3 SE-3-34 1 Rm 20/21 Sump #4 3 9

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 7, SEB Shop and Equipment Survey Unit CLASS 1

'4V -

CLASS 2 CLASS 3 7 8' II 1B11, 1A2 4'AI)

SEB - SHOP AND EQUIPMENT BUILDING MEZZANINE Survey Description FSSP Unit Class (Rm=Room; Fl=Floor; Lw=Lower wall; Classification UUw=Upper wall; WI=Window ledges)

SE-2-4 3 Mezzanine Class 3 areas, Fl, Lw, Uw, Ceiling 3 10

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 8, SEB Basement Sumps 1 and 2 (Survey Unit SE-3-32) 11--2 l A -> \ ,- Q. - 'I II

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 9, SEB Basement Sump 3 (Survey Unit SE-3-32) 12

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 10, Views of SEB Boiler Room Drains and Floor Details (Survey Unit SE-1-7) 13

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 11, Views of SEB Shop and Equipment Room (Survey Unit SE-I-1) ta A -a 'a.,

%A-a CI-n I -- LA-n C:-e 14

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 12, Views of SEB Shop Walls and Windows(Survey Unit SE-1-6)

North Wall Steel Looking West 15

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 13, Views of SEB First Floor Hallways (Survey Unit SE-1-7)

PhAnin WnIli-i, I ,w^Ie;n- ýc.f

- f --- I I-I . . .. I -- -- .- -- ..

16

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 14, SEB Boiler Room Floor Details (Survey Unit SE-1-7) 17

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 15, Views of SEB Water Treatment Room (Survey Unit SE-1-7)

Water Treatment Room General Area View Lookino North 18

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 16, General Views of SEB Mezzanine (Survey Unit SE-2-2)

PRnm Hinacfn 11QAl Mannrol Arga krnrfh I&l JL IAt'*A\

• I A 19

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 17, SEB Mezzanine Room 14 Landing (Survey Unit SE-2-3)

Room 14 Looking South 20

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 18, SEB Mezzanine (2 a FI.) Office Rooms (Survey Unit Se-2-4)

Office Room 3 Lookina West 21

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 19, SEB Cold Pipe Tunnel Floor (Survey Unit SE-3-8)

General Area View of Floor Surface Lookina East.

22

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 20, Views of SEB Cold Pipe Tunnel Walls (Survey Unit SE-3-15) 23

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 21, Views of SEB Cold Pipe Tunnel Ceiling(Survey Unit SE-3-23)

General Area View Lookina East

- I I

24

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 22, Views of SEB Cooling Tower Basin Area of CPT (Survey Unit SE-3-26)

General Area View Lookina North 25

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 23, Views of SEB Cooling Tower Basin CPT Walls (Survey Unit SE-3-28)

General Area View East Wall Looking North 26

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 24, Views of SEB CPT Connecting Tunnel (Survey Unit SE-3-30)

KIl*-',k C,.. Ik W-l11--'J,, t-2r-*-,'l A -- \lX A-, I *l KnlI-kl,*ll 27

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 25, Views of SEB Basement (Survey Unit SE-3-32) 28

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 26, SEB Basement Stairwell (Survey Unit SE-3-32)

~IprpIDnnm Qn.ff^m ^f Q~niminAla I ^^L&inn Qrna ith 29

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 27, Views of SEB Roof (Survey Unit SE-4-1)

West End - looking North West End - looking North West Looking east toward addition Penetrations with tar and gravel area 30

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 28, Views of Unusual Condition Measurement (UMC) Areas (Survey Unit SE-3-5)

BSI Iu ed Core Bores 31

Plum Brook Reactor Facility FSSR, Attachment 2 Appendix A, Rev.0, Exhibit 29, Views of Unusual Condition Measurement (UMC) Areas (Survey Unit SE-3-16)

I 11'hA4 I ^^nr ýtwr in fh %A/-&+t ntraI *nm ,f-n fl- Q.- - I 1 32