FINAL STATUS DECONTAMINATION & CLEANUP SURVEY …4 Arrow Drive Woburn, MA 01801 JANUARY 19, 2018....

FINAL STATUS DECONTAMINATION & CLEANUP SURVEY REPORT

Former Benrus Clock Factory Site 145 Cherry Ave

Waterbury, Connecticut

Prepared for:

Cherry Avenue Partners, LP 325 Spalding Gates Court

Atlanta, Ga 30328

Prepared by:

DDES, LLC 4 Arrow Drive

Woburn, MA 01801

JANUARY 19, 2018


FORMER BENRUS CLOCK FACTORY SITE

TABLE OF CONTENTS

i

1.0 EXECUTIVE SUMMARY .............................................................................................. 1

2.0 FACILITY OPERATING HISTORY .................................................................................. 3

2.2 RADIOACTIVE MATERIAL USE ................................................................................................................................ 32.3 POTENTIAL CONTAMINANTS ................................................................................................................................. 32.4 OPERATIONAL RADIOLOGICAL SURVEYS ................................................................................................................... 32.5 SPILLS AND UNCONTROLLED RELEASE OF RADIOACTIVITY ............................................................................................ 42.6 POTENTIALLY IMPACTED FACILITIES AND LABORATORIES ............................................................................................. 42.7 NON-IMPACTED AREAS ........................................................................................................................................ 4

3.0 FACILITY CLEANUP CRITERIA ...................................................................................... 5

3.2 DCGL DEVELOPMENT ......................................................................................................................................... 5Table 3-2 Former Benrus Clock Company’s Administrative Limits for Surveys .................................................... 63.3 ALARA GOALS .................................................................................................................................................. 6

4.0 PROJECT MANAGEMENT AND ORGANIZATION .......................................................... 7

5.0 TRAINING ................................................................................................................. 8

6.0 ENVIRONMENTAL MONITORING PROGRAM .............................................................. 9

7.0 RADIOACTIVE WASTE MANAGEMENT ..................................................................... 10

8.0 SURVEY INSTRUMENTATION ................................................................................... 11

8.1 INSTRUMENT CALIBRATION ................................................................................................................................. 118.2 FUNCTIONAL CHECKS ......................................................................................................................................... 118.3 DETERMINATION OF COUNTING TIMES AND MINIMUM DETECTABLE CONCENTRATIONS ................................................. 118.3.1 Static Counting ......................................................................................................................................... 118.3.2 Ratemeter Scanning ............................................................................................................................... 128.3.3 Smear Counting ......................................................................................................................................... 128.4 RADIOLOGICAL INSTRUMENTATION SPECIFICATIONS ............................................................................................. 13

9.0 DATA QUALITY OBJECTIVES ..................................................................................... 15

10.0 CLASSIFICATION OF AREAS ...................................................................................... 16

10.1 CLASS 1 AREAS ................................................................................................................................................. 1610.2 CLASS 2 AREAS ................................................................................................................................................. 1610.3 CLASS 3 AREAS ................................................................................................................................................. 1710.4 SURVEY UNITS ................................................................................................................................................. 1710.5 SURFACE CONTAMINATION SCANS ....................................................................................................................... 1710.6 TOTAL SURFACE ACTIVITY MEASUREMENTS ........................................................................................................... 1810.6.1 Determining the Number of Samples ...................................................................................................... 1810.6.2 Determination of the Relative Shift ......................................................................................................... 1910.6.3 Determination of Acceptable Decision Errors.......................................................................................... 1910.6.4 Determination of Number of Data Points (Sign Test) .............................................................................. 1910.6.5 Determination of Sample Locations......................................................................................................... 2010.6.5.1 Determining Class 1 and 2 Sample Locations .............................................................................. 2110.6.5.2 DETERMINING CLASS 3 SAMPLE LOCATIONS ................................................................................................... 2210.7 REMOVABLE CONTAMINATION MEASUREMENTS .................................................................................................... 22


FORMER BENRUS CLOCK FACTORY SITE

TABLE OF CONTENTS

ii

11.0 DECONTAMINATION ............................................................................................... 23

12.0 DATA QUALITY ASSESSMENT AND INTERPRETATION OF SURVEY RESULTS ............... 24

12.3 FINAL STATUS SURVEY RESULTS ........................................................................................................................... 24

13.0 QUALITY ASSURANCE SURVEYS ............................................................................... 29

APPENDIX A – INSTRUMENT CALIBRATION CERTIFICATES

APPENDIX B – MINIMUM DETECTABLE CONCENTRATION CALCULATIONS

APPENDIX C – FACILITY MAPS

APPENDIX D – STATISTICAL DATA

APPENDIX E – SURVEY DATA FOR STRUCTURES AND SYSTEMS

APPENDIX F – TOTAL EFFECTIVE DOSE EQUIVALENT CALCULATIONS

APPENDIX G – QUALITY ASSURANCE DATA

APPENDIX H – SURVEY CODING SYSTEM

Former Benrus Clock Factory Site Final Status Survey Report

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1.0 EXECUTIVE SUMMARY

Decontamination Decommissioning and Environmental Services (DDES) was retained by Cherry Avenue Partners LP to perform radium (226Ra) cleanup operations at the Former Benrus Clock Factory Site in accordance with the requirements of the Cleanup Plan dated May 17th, 2017. The decontamination and final status survey work began on September 25th and continued through January 9th 2018. The cleanup project was performed using DDES Massachusetts Radioactive Materials License 56-0623 under reciprocal agreement with the Nuclear Regulatory Commission (NRC).

The structures and surfaces of the interior of the affected building were surveyed to demonstrate compliance with the established cleanup criteria. The surveys were designed and executed using the guidance provided in NUREG 1757, “Consolidated NMSS Decommissioning Guidance”; and NUREG 1575, “Multi-Agency Radiation Survey and Site Investigation Manual” (MARSSIM). The final status survey methods and techniques for the evaluation of potentially impacted radiological areas followed MARSSIM guidance to demonstrate compliance with the specified dose based cleanup criteria. These methods ensure technically defensible data is generated to aid in determining whether or not these facilities meet the cleanup criteria for unrestricted use.

The radionuclide Radium (226Ra) was present at the site. DDES performed a radiological Historic Site Assessment (HSA) prior to beginning the characterization and cleanup that was based on NUREG 1575, MARSSIM. The nuclide of concern for the Former Benrus Clock Company Site has been identified in Table 2-1.

Characterization and Final Status Surveys were designed to implement the protocols and guidance provided in MARSSIM to demonstrate compliance with the Cleanup Plan. Default screening values are usually specified in NUREG 1757, Volume 1, Appendix B. However, a default screening value is not provided for 226Ra on surfaces. DandD v.2.4 was used to determine the Derived Concentration Guideline Level (DCGL) with a corresponding dose measurement of 19 mrem. These methods ensure technically defensible data is generated to demonstrate the facility is acceptable for unrestricted use.

Based upon the results of the Final Status Survey, the facility meets the requirement for cleanup goals based upon the following:

All final status scanning measurements were below the DCGL.

All final status static measurements were below the DCGL.


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None of the removable measurements obtained exceeded the administrative removable contamination limit of 20 dpm/100cm2 for 226Ra.

The greatest final status survey structure contamination survey measurement from within the Former Benrus Clock Company Site was at 599 dpm/100cm2 for 226Ra.

The calculated total effective dose equivalent (TEDE) from any potential radioactive materials in the specified areas within the Former Benrus Clock Factory Site were calculated to be 4.7 mrem/year. This was based on the Nuclear Regulatory Commission (NRC) DandD Version 2.4 default building occupancy scenario using the highest average total contamination value from all survey units.


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2.0 FACILITY OPERATING HISTORY

DDES, LLC performed a Historical Site Assessment (HSA) of the facilities in April of 2017. The HSA was designed to determine the existing radiological status of the facilities.

2.2 Radioactive Material Use

The Benrus Clock Company was founded in New York City in 1921 and operated a watch factory at 145 Cherry Avenue in Waterbury, Connecticut. Prior to the Benrus Clock Company, the facility was once the movement factory for the Waterbury Clock Company. The Benrus Clock Factory Site was known to have produced watches containing radium-luminous paint.

One Public Health Assessment Survey from 1998 issued by the Agency for Toxic Substances & Disease Registry (ATSDR) was located. This report provided limited dose rate surveys of the site. Dose rates in excess of twice background were noted on the 4th, 5th and 7th floors of the facility.

A limited spot-check survey was performed on the 4th, 5th and 7th floors of the facility by Scientech in 2003. Elevated levels were noted in each of the areas previously surveyed. These areas of contamination needed further quantification to determine the level of remediation necessary to meet the free release criteria. Previous surveys were limited due to the amount of material being stored in the facility by the previous tenant.

2.3 Potential Contaminants

Table 2-1 lists the potential radioactive contaminants as identified by the HSA.

Table 2-1 Potential Contaminants

Radionuclide Half-Life Dispersible Form Half Life >120 Days

226Ra 1,600 years Yes Yes

2.4 Operational Radiological Surveys

To our knowledge, the Former Benrus Clock Factory did not perform radioactive surveys when 226Ra paints were used. DDES performed personnel surveys during characterization and remediation efforts. No detectable personal contamination was found on personnel or visitors for the duration of the cleanup project. There were several areas of removable contamination identified during the Characterization Survey on the 7th floor. All locations were below 20 dpm/100cm2 during the execution of the Final Status Survey.


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2.5 Spills and Uncontrolled Release of Radioactivity

Since no radiological records were required to be kept, no radiological spills had been reported over the history of the site.

2.6 Potentially Impacted Facilities and Laboratories

Table 2-2 lists areas that have been potentially impacted by the use of radioactive material and were evaluated against the cleanup criteria.

Table 2-2 Potentially Impacted Areas

Location Isotope Class

1st Floor Ra-226 1

2nd Floor Ra-226 1

3rd Floor Ra-226 1

4th Floor Ra-226 1

5th Floor Ra-226 1

6th Floor Ra-226 1

7th Floor Ra-226 1

Stairwell Ra-226 3

2.7 Non-Impacted Areas

The following locations have not been impacted by radioactivity associated with activities based on information obtained during the HSA and characterization of the site.

Building Exterior

Walls and surfaces greater than 2 meters in height

Attached Buildings and Additions


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3.0 FACILITY CLEANUP CRITERIA

The radiological release criteria in accordance with Title 10 Code of Federal Regulations (CFR) Part 20 “Standards for Protection Against Radiation, Subpart E – Radiological Criteria for License Termination” were used for cleanup of the facility. While the facility was not specifically licensed by the NRC, the regulations provide the framework to achieve unrestricted reuse of the site with regard to radiological controls.

Specifically, the areas of the Site being released under this cleanup effort were surveyed in accordance with the guidance and protocols contained in MARSSIM to demonstrate compliance with the release criteria. The criteria was that residual radioactivity results in a TEDE to an average member of the critical group that does not exceed 19 mrem per year and that the residual radioactivity has been remediated to levels that are as low as reasonably achievable (ALARA).

DCGLs are radionuclide-specific concentration limits used during cleanup to achieve the regulatory dose standard that permit the release of the property. The DCGL applicable to the average concentration over a survey unit is called the DCGLW and the DCGL applicable to limited areas of elevated concentrations within a survey unit is called the DCGLEMC (NRC 2006). These values were used as a guide to establish compliance with the site cleanup criteria.

3.2 DCGL Development

The DCGL development analyses simulate the behavior of residual radioactivity over one year, a period during which peak annual doses from the radionuclides of primary interest would be expected to occur. DCGLs are developed for residual radioactivity that will result in 25 mrem per year dose to the average member of the critical group.

The NRC has published default screening values (DSVs) in NUREG 1757, Volume 1, Appendix B for commonly used radionuclides. These default screening values are based on 25 mrem/year. However a DSV was not published for 226Ra. NRC DandD code ver. 2.4 was used to calculate the DSV for 226Ra. Furthermore, the State of Connecticut regulations require facilities meet a TEDE of 19 mrem for unrestricted use. Table 3-1 presents the DCGLs based on 19 mrem.


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Table 3-1 Established DCGLw for Survey based on 19 mrem/yr

Isotope Total(DPM/100 cm2)

Removable (DPM/100 cm2)

226Ra 819 82

DDES and Cherry Avenue Partners, LP established a conservative action limit for 226Ra. It is presented in table 3-2. Non impacted material backgrounds were established prior to facility characterization and final status survey activities.

Table 3-2 Former Benrus Clock Company’s Administrative Limits for Surveys

Isotope Total(DPM/100 cm2)

Removable (DPM/100 cm2)

226Ra 100 20

3.3 ALARA Goals

Administrative limits of radionuclides were established far below the DCGLw values. The administrative limits were established for free release of materials and final status survey contamination levels. The administrative goals were met for removable in all final status survey readings. The administrative goals were met in 88% of all final status total readings.


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4.0 PROJECT MANAGEMENT AND ORGANIZATION

DDES LLC has maintained primary responsibility for all activities conducted under the requirements of the Cleanup Plan and the Final Status Survey. DDES holds Massachusetts Radioactive Material License No. 56-0623 under reciprocity with the NRC. The point of contact between applicable regulatory authorities and DDES has been the DDES Principal. DDES personnel authorized under the license were on site during cleanup operations involving radioactive materials.


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5.0 TRAINING

DDES, LLC performed annual radiation safety training and project specific training for DDES personnel and subcontractors as required by DDES, LLC’s license conditions.


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6.0 ENVIRONMENTAL MONITORING PROGRAM

The scope of this cleanup project was limited to the interior of the facilities; therefore, a project-specific environmental monitoring program was not required.


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7.0 RADIOACTIVE WASTE MANAGEMENT

Approximately 90 cubic yards of radioactive waste was generated during this project. The majority of the waste was wood flooring components. Also included were contaminated radiators, bricks, vacuum bags, sheeting, and PPE. The waste was shipped offsite on 02/13/2018 for direct disposal at U.S. Ecology in Grandview, Idaho.


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8.0 SURVEY INSTRUMENTATION

8.1 Instrument Calibration

Portable field instruments were calibrated with National Institute of Standards and Technology (NIST) traceable sources for the nuclides of concern within the previous year. Instrument calibration sheets have been included in Appendix A.

8.2 Functional Checks

Functional checks for portable instrumentation were performed daily when in use. The background, source check, and field measurement count times for radiation detection instrumentation were validated daily to ensure that statistically valid data was obtained. Background readings were taken as part of the daily instrument check and compared with the acceptance range for instrument performance and site conditions.

8.3 Determination of Counting Times and Minimum Detectable Concentrations

Minimum counting times for background determinations and measurement of total and removable contamination were chosen to provide a minimum detectable concentration (MDC) that met the Final Status Survey DQOs. MDC calculations are presented in Appendix B. Instrumentation count times and scanning rates were determined using the following equations listed in Sections 8.3.1, 8.3.2 and 8.3.3 below:

8.3.1 Static Counting

Static counting Minimum Detectable Concentration at a 95% confidence level were calculated using the following equation, which is an expansion of NUREG 1507, "Minimum Detectable Concentrations with Typical Radiation Survey Instruments for Various Contaminants and Field Conditions", (Strom & Stansbury, 1992):

2100

)1(29.33

cm

AEt

t

ttB

MDC

tots

b

ssr

static

Where: MDCstatic = minimum detectable concentration level in dpm/100cm2

Br = background count rate in counts per minute tb = background count time in minutes ts = sample count time in minutes

Etot = total detector efficiency for radionuclide emission of interest (includes combination of instrument efficiency and 0.25 surface efficiency for beta emitters <400 keV max and 1.00 surface efficiency for gamma emitters)


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A = detector probe area in cm2

8.3.2 Ratemeter Scanning

Scanning Minimum Detectable Concentration at a 95% confidence level was calculated using the following equation, which is a combination of MARSSIM equations 6-8, 6-9, and 6-10:

2100

60'

cm

AEp

ibd

MDC

tot

i

scan

Where:

MDCscan = minimum detectable concentration level in dpm/100 cm2

d’ = desired performance variable (1.38)

bi = background counts during the residence interval

i = residence interval

p = surveyor efficiency (0.5)

Etot = total detector efficiency for radionuclide emission of interest (includes combination of instrument efficiency and 0.25 surface efficiency for beta emitters <400 keV max) and 0.50 surface efficiency for beta emitters >400keV max and 1.0 surface efficiency for gamma emitters

A = detector probe area in cm2

8.3.3 Smear Counting

Smear counting Minimum Detectable Concentration at a 95% confidence level was calculated using the following equation, which is NUREG 1507, "Minimum Detectable Concentrations with Typical Radiation Survey Instruments for Various Contaminants and Field Conditions", (Strom & Stansbury, 1992):

Et

t

ttB

MDCs

ssr

smearb

)1(29.33

Where: MDCsmear = minimum detectable concentration level in dpm/smear

Br = background count rate in counts per minute tb = background count time in minutes ts = sample count time in minutes E = instrument efficiency for radionuclide emission of interest


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8.4 Radiological Instrumentation Specifications

Field instruments were selected based on the DQOs in Section 9.0. Table 8-1 shows typical field instruments and associated efficiencies that were used for the Final Status Survey.

Table 8-1 Radiological Field Instruments

Detector

Model

Detector

Type

Detector

Area

Meter

Model

Window

Thicknes

s

Typical Total

Efficiency

Ludlum 43-37

Floor Monitor Gas Flow Proportional

584 cm2

Ludlum 2221 0.4 mg/cm2

10.6 % (230Th)

Ludlum

43-93

ZnS(Ag)

Scintillator 100 cm2

Ludlum 2224-1 0.8 mg/cm2

10.4% (230

Th)

N/A Alpha/Beta ZnS(Ag)

Scintillator 20.26 cm2 Ludlum 3030 0.4 mg/cm2

34.0% (239

Pu)

N/A NaI (Tl) Scintillation 1” x 1” Ludlum 19 N/A 175 cpm/µR/hr

NOTES: These are approximate values based primarily on manufacturer's ratings. The sensitivities depend on background, count time, and other factors.

To assist with planning activities, estimated scanning MDCs for the radionuclide of interest were obtained for field survey instruments by reviewing available information, and these values are listed in Table 8-2.


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Table 8-2 Typical Operating Instrument Operating Parameters

Measurement

Type

Detector

Model

Meter

Model

Scan

Rate

Count

Time

Background

(cpm)

MDC

(dpm/100cm2)

Surface ScansLudlum

43 - 93

Ludlum

2224-1

2

in./sec. N/A 285 179 (230Th)

Surface Scans

Ludlum

43 - 37B

Floor

Monitor

Ludlum

2221

4

in./sec. N/A 740 69 (230Th)

Total Surface

Activity

Ludlum

43 - 93

Ludlum

2224 N/A 1 Min 235 70 (230Th)

Exposure

Rate N/A

Ludlum

19 N/A N/A 12 (µR/hr) N/A

Removable

Activity N/A Ludlum

3030 N/A 1 Min

0.3 (α)

37.3(β)

13 (239Pu)

93 (99Tc)

The scanning MDCs presented in Table 8-2 are representative of those that reasonably can be expected to be obtained with currently available instruments under conditions typically encountered in the field. These values were obtained from reported values and scanning experience.


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9.0 DATA QUALITY OBJECTIVES

The following identifies the data quality objectives (DQOs) used for the project radiological surveys:

Static measurements were taken to achieve a MDCstatic of 70 dpm/100cm2 Alpha.

Hand scanning was conducted at a scan speed to achieve a MDCscan of 179 dpm/100cm2 for Alpha.

Floor scanning was conducted at a scan speed to achieve a MDCscan of 69 dpm/100cm2 for Alpha.

Removable contamination measurements had a MDC of 13 dpm/100cm2 for Alpha.

Removable contamination measurements had a MDC of 93 dpm/100cm2 for Beta.

Scenario A was used for the null hypothesis.

Decision error and probability rates were set to 0.05 for Type I and Type II errors.


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10.0 CLASSIFICATION OF AREAS

Different areas of the project premises, facilities and areas of interest were classified based on potential for radioactive contamination. Four classifications could have been used:

Class 1: impacted areas that, prior to remediation, are expected to have concentrations of residual radioactivity that exceed the DCGLw;

Class 2: impacted areas that, prior to remediation, are not likely to have concentrations of residual radioactivity that exceed the DCGLw;

Class 3: any impacted areas that have a low probability of containing residual radioactivity; and

Non-impacted: areas without reasonable potential for radioactive contamination from previous use or cleanup activities.

Non-impacted areas are building surfaces or systems that did not have residual radioactivity present from previous activities. The following areas were classified as non-impacted:

Exterior Building Surfaces

Walls and surfaces greater than 2 meters in height

Attached buildings and additions

Impacted areas are identified in Section 2.6 based on information obtained during the HSA and characterization. Each impacted areas classification was confirmed by subsequent characterization and final status survey data. Impacted areas were those areas that had potential residual radioactivity from previous site activities. Impacted areas were subdivided into Class 1, Class 2 or Class 3 areas. Class 1 areas had the greatest potential for contamination and therefore received the highest degree of survey effort for the final status survey using a graded approach, followed by Class 2, and then by Class 3. Impacted sub-classifications are defined as follows:

10.1 Class 1 Areas

Areas with the highest potential for contamination, and meet the following criteria: (1) impacted; (2) potential for delivering a dose above the release criterion; (3) potential for small areas of elevated activity; and (4) insufficient evidence to support classification as Class 2 or Class 3.

10.2 Class 2 Areas

Areas that met the following criteria: (1) impacted; (2) low potential for delivering a dose above the release criterion; and (3) little or no potential for small areas of elevated activity. There were no Class 2 survey units included in this Final Status Survey.


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10.3 Class 3 Areas

Areas that meet the following criteria: (1) impacted; (2) little or no potential for delivering a dose above the release criterion; and (3) little or no potential for small areas of elevated activity.

The radiological status of the facility was determined by reviewing the limited amount of historical survey records and the characterization survey.

10.4 Survey Units

Areas within a survey unit had a similar usage history and contamination potential and were contiguous areas of the same area classification. Areas of similar construction and composition were grouped together as survey units and tested individually against the DCGLs and the null hypothesis to show compliance with the release criteria. Survey units were of homogeneous construction, contamination potential, and contamination distribution.

The number of discrete sampling locations needed to determine if a uniform level of residual radioactivity existed within a survey unit does not depend on the survey unit size. However, the sampling density reflected the potential for small elevated areas of residual radioactivity. Survey units were sized according to the potential for small elevated areas of residual radioactivity.

Recommended maximum survey unit sizes from MARSSIM are provided in Table 10-1.

Table 10-1 Recommended Maximum Survey Unit Size Limits

Type of Survey Unit Class 1 Class 2 Class 3

Structures Up to 100 m2 100 m2 to 1,000 m2 No Limit

10.5 Surface Contamination Scans

Scanning was used to identify locations within the survey unit that exceeded the investigation level. These locations were marked and received additional investigation to determine the concentration, area, and extent of the contamination. Scanning surveys are designed to detect small areas of elevated activity that were not detected by the measurements using the systematic pattern. Floor surfaces were scanned by floor monitor across the entire floor. Wall surfaces and columns were scanned by hand. Table 10-2 summarizes the percentage of accessible building structural surfaces scanned based on classification.


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Table 10-2 Scan Survey Coverage by Classification

Classification Recommended Scan Coverage Actual Coverage

1 100% 100%

3 Judgmental 50%

For the purposes of the Final Status Survey, Class 1 survey units received a scan survey of 100% and Class 3 survey units received a scan survey of 50%, of all accessible horizontal surfaces and vertical surfaces to a height of two (2) meters.

Scanning was performed by moving the probe over the subject surface at a distance of approximately 1.0 cm or less at a rate less than the maximum scan rate necessary to achieve the specific MDCscan for the instrument. Areas of elevated activity that were detected during the scan surveys were marked and total and removable surface activity measurements taken. However, these total surface activity measurements are in addition to the static measurements required for the statistical test.

The derivation of scan and fixed MDCs took into account instrument efficiencies (surface and detector), scan rates and distances over surfaces, surveyor efficiency, and minimum detectable count rate, using guidance in the MARSSIM (NRC 2000) and NUREG 1507 (Abelquist, et al. 1998).

The survey methodology specified in this section is consistent with the provisions of NUREG-1757, Volume 2 (NRC 2006) and with the guidance found in NUREG-1575, Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM) (NRC 2000).

10.6 Total Surface Activity Measurements

Total activity measurements were taken on building surfaces and system internals to the extent practical in impacted areas utilizing instrumentation of the best geometry based on the surface at the survey location. Locations of elevated activity were identified and marked during the scan survey. Total surface activity measurements were taken at each determined sample location. The Survey Coding System used to identify each sample location is presented in Appendix H. Hand-held monitor count times were determined based on the MDCstatic of the applicable survey instrument.

10.6.1 Determining the Number of Samples

A minimum number of samples were needed to obtain sufficient statistical confidence that the conclusions drawn from the samples are correct. The number of samples depended on the relative shift. Initial calculations have been performed to determine an estimated standard deviation and Lower Bound of the Gray Region (LBGR) for determination of the relative shift. Specific data was selected from


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areas that appear to meet the release criteria using the assumption that remedial actions will remove locations greater than the DCGLW.

The survey design for surfaces and structures were based on the Sign test. The minimum number of samples calculated using MARSSIM Equation 5-2 was 11 sample locations.

10.6.2 Determination of the Relative Shift

The number of required samples depended on the ratio involving the activity level to be measured

relative to the variability in the concentration. The ratio used is called the Relative Shift, /S and is defined in MARSSIM as:

S

S

LBGRDCGL

/

Where:

DCGL = derived concentration guideline level

LBGR = concentration at the lower bound of the gray region. The LBGR is the average concentration to which the survey unit should be cleaned in order to have an acceptable probability of passing the test

S = an estimate of the standard deviation of the residual radioactivity in the survey unit

For the purpose of this survey, an estimated standard deviation was pre-determined based on the expected total activity levels at the time of the FSS. The LBGR was initially be set at one-half of the DCGLW.

10.6.3 Determination of Acceptable Decision Errors

A decision error is the probability of making an error in the decision on a survey unit by failing a unit that should pass (β decision error) or passing a unit that should fail (α decision error). MARSSIM uses the terminology α and β decision errors; this is the same as the more common terminology of Type I and Type II errors, respectively. The decision errors were set at 0.05 for Type I errors and 0.05 for Type II errors.

10.6.4 Determination of Number of Data Points (Sign Test)

The number of direct measurements for a particular survey unit, employing the Sign Test, was determined from MARSSIM Table 5.5, which is based on the following equation (MARSSIM equation 5-2):


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2

2

11

5.04

SignP

ZZN

Where:

N = number of samples needed in the survey unit

Z1- = percentile represented by the decision error

Z1- = percentile represented by the decision error

SignP = estimated probability that a random measurement will be less than the DCGL when the survey unit median is actually at the LBGR

110.5-0.9986504

1.645+1.6452

2

N

Note: SignP is determined from MARSSIM Table 5.4

MARSSIM recommends increasing the calculated number of measurements by 20% to ensure sufficient power of the statistical tests and to allow for possible data losses. MARSSIM Table 5.5 values include an increase of 20% of the calculated value of 11 sample locations to 13 sample locations.

10.6.5 Determination of Sample Locations

Determination of Class 1 survey unit sample locations was accomplished by first determining sample spacing and then systematically plotting the sample locations from a randomly generated start location. The random starting point of the grid provides an unbiased method for obtaining measurement locations used in the statistical tests.

Survey protocols for all areas are summarized in Table 10-3.


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Table 10-3 Survey Sample Placement Overview

Survey Unit Classification DCGLw

Comparison

Elevated Measurement Comparison

Measurement Locations

Impacted Class 1 Yes N/A Systematic/Random Start

Class 2 N/A N/A Systematic/Random Start

Class 3 Yes N/A Judgmental

Non-Impacted None None None

10.6.5.1 Determining Class 1 and 2 Sample Locations

In Class 1 survey units, the sampling locations were established in a unique pattern beginning with the random start location and the determined sample spacing. After determining the number of samples needed in the survey unit, sample spacing was determined from MARSSIM equation 5-8:

gridsquareafor N

AL

Where:

L = sample spacing interval

A = the survey unit floor area

N = number of samples needed in the survey unit

Class 1 & 2 grid areas included walls to a height of 2 meters. Maps were generated for each survey unit’s permanent surfaces included in the statistical tests. Maps are located in Appendix C. Random starting points were determined using computer-generated random numbers coinciding with the x and y coordinates of the total survey unit. A grid was plotted across the survey unit surfaces based on the random start point and the determined sample spacing. A measurement location was plotted at each intersection of the grid plot. For the purposes of this report all survey units were considered Class 1 and Class 3 units. There were no Class 2 survey units included in this scope.


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10.6.5.2 Determining Class 3 Sample Locations

Class 3 sample locations were performed using judgment in locations where high traffic would occur in the stairwell, such as landings and handrails.

10.7 Removable Contamination Measurements

Removable contamination measurements (smears) were collected on building surfaces and structures at each total activity sample location to determine the potential removable contamination. 226Ra contamination levels were evaluated using removable contamination measurements (wipe test). This approach assumed that the removable portion is 10% of the total fixed contamination. An area of approximately 100 cm2 was wiped for each sample location.


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11.0 DECONTAMINATION

Decontamination is the physical or chemical process of reducing and preventing the spread or potential exposure from contamination. Decontamination included the use of commercially available materials and/or equipment that effectively removed radioactive materials from surface areas so that the contamination could be collected and properly disposed. In some cases, the contamination has been absorbed into the material and the impacted areas must be removed. The Former Benrus Clock Factory Site had brick, metal, concrete and wood surfaces that were impacted by 226Ra contamination.

Wood Flooring System

The flooring of the Benrus Clock Factory was composed of a top layer of 2-inch maple planking with a diagonal 8-inch by 1-inch subfloor. These horizontal flooring layers were supported by sistered 2-inch by 6-inch floor joists. A number of floor surfaces were decontaminated below the cleanup criteria by sanding. Other areas required complete removal as contamination had migrated between materials.

The top layer of maple flooring had to be removed in locations on the 3rd, 4th, 5th, 6th, and 7th

floors due to 226Ra contamination between the flooring. Approximately 4,660 ft2 of the top layer of flooring was removed and packaged for radioactive waste disposal. The second layer of flooring ranged from non-impacted to heavily impacted by radioactive contamination. The second layer of subfloor was scanned to identify areas exceeding the cleanup criteria. Approximately 2,000 ft2 of subfloor required sanding under negative pressure to remediate. Approximately 1,200 ft2 of the second layer of subflooring required complete removal. Approximately 1,460 ft2 met the cleanup criteria without further remediation. In locations where the second layer of floor was removed, the supporting floor joists were surveyed for 226Ra contamination exceeding the cleanup criteria. Approximately 480 ft2 the floor joists required removal. Radioactive contamination was also identified in concrete surfaces on the 1st, 5th, and 7th floors. Approximately 250 ft2 of concrete floors required grinding to remove surficial contamination.

The walls were impacted by radioactive contamination on the 3rd, 4th, 5th, 6th, and 7th floors. Approximately 750 ft2 of impacted walls were decontaminated by needle gunning to remove the top surface of the brick. In addition 12 steam radiators were identified as contaminated, removed and disposed of as radioactive waste. There were a number of impacted metal doors that were sanded or completely removed as part of the cleanup project.


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24

12.0 DATA QUALITY ASSESSMENT AND INTERPRETATION OF SURVEY RESULTS

The statistical guidance contained in Section 8 of MARSSIM was used to determine if areas are acceptable for unrestricted reuse and whether additional surveys or sample measurements were required.

12.1 Preliminary Data Review

A preliminary data review was performed for each survey unit to identify any patterns, relationships or anomalies. Additionally, measurement data were reviewed and compared with the DCGLs and administrative limits to confirm the correct classification of survey units. All statistical calculations of average, standard deviations, minimum and maximum values are presented in Appendix D.

12.2 Determining Compliance for Building Surfaces and Structures

Removable contamination measurements were compared directly to the applicable DCGLs. Additionally, all removable contamination measurements were compared to the applicable administrative limits to determine if an area required further examination. All smears collected during the final status surveys were less than the applicable administrative limits and significantly less than the established DCGLs for removable activity. Therefore, the remediation’s success was determined based on total activity measurements.

All total alpha surface activity measurements were compared directly to the DCGL. All total surface activity measurements collected during final status surveys were less than the established DCGLs.

Therefore, the null hypothesis can be rejected and the facility meets the cleanup criteria and is suitable for repurpose. Total activity and removable contamination measurement results for all surface and structure survey units are provided in Appendix E.

12.3 Final Status Survey Results

All removable contamination measurements were below both the Administrative Limits of 20 dpm/100cm2 for 226Ra and the DCGLw of 82 dpm/100cm2 for 226Ra. All total contamination measurements taken during the Final Status Survey were below the DCGLw of 819 dpm/100cm2

for 226Ra. The final status survey results are summarized in Table 12-1.


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Table 12-1 Final Status Survey Results Summary

Survey Unit

Class Survey Points

Removable Contamination(226Ra DPM/100cm2)

Total Contamination(226Ra DPM/100cm2)

Locations Exceeding

DCGLwAve. σ Min. Max. Ave. σ Min. Max.

1-1 1 34 0.61 1.4 0.0 5.9 29.8 29.8 -19.3 87.0 0

1-2 1 18 0.7 1.3 0.0 2.9 9.1 24.0 -19.3 58.0 0

1-3 1 27 1.2 1.7 0.0 5.9 1.1 18.2 -19.3 58 0

1-4 1 22 -2.3 1.3 -2.9 0.0 19.6 30.7 -18.8 84.5 0

1-5 1 20 -2.5 1.1 -2.9 0.0 7.5 21.9 -18.8 56.3 0

1-6 1 20 0.6 1.2 0.0 2.9 8 20.0 -9.4 56.3 0

1-7 1 31 -2.6 1.0 -2.9 0.0 1.8 19.2 -28.2 46.9 0

2-1 1 25 0.4 1.0 0.0 2.9 5.3 21.0 -28.2 75.1 0

2-2 1 18 -2.6 1.0 -2.9 0.0 6.8 24.7 -18.8 84.5 0

2-3 1 24 -2.1 1.4 -2.9 0.0 12.1 22.4 -18.8 84.5 0

2-4 1 22 -2.4 1.5 -2.9 2.9 10.2 20.5 -18.8 56.3 0

2-5 1 22 0.3 0.9 0.0 2.9 4.3 22.0 -28.2 56.3 0

2-6 1 22 0.9 1.7 0.0 5.9 4.3 12.9 -18.8 28.2 0

2-7 1 31 0.5 1.1 0.0 2.9 3.9 13.9 -18.8 37.6 0

3-1 1 22 2.0 2.5 0.0 8.8 30.3 37.1 -9.4 131.5 0

3-2 1 16 -1.1 1.8 -2.9 2.9 27.0 31.6 -9.4 103.3 0

3-3 1 18 -1.3 2.3 -2.9 5.9 35.5 34.6 -28.2 122.1 0

3-4 1 20 0.3 0.9 0.0 2.9 3.3 12.7 -18.8 28.2 0

3-5 1 22 0.7 1.3 0.0 2.9 -5.7 14.8 -29.0 19.3 0

3-6 1 22 0.9 1.9 0.0 5.9 -4.0 15.1 -29.0 29 0

3-7 1 31 3.1 2.5 0.0 8.8 -3.7 16.7 -29.0 38.6 0

4-1 1 25 0.9 1.6 0.0 5.9 35.2 21.9 -9.7 87.0 0

4-2 1 24 1.7 1.9 0.0 5.9 33.6 31.2 -18.8 112.7 0

4-3 1 27 -2.1 1.6 -2.9 2.9 34.0 26.6 -9.7 106.3 0

4-4 1 20 0.9 1.4 0.0 2.9 54.1 56.7 -19.3 193.2 0

4-5 1 22 1.7 2.5 0.0 8.8 119.1 106.8 9.4 441.3 0

4-6 1 20 0.6 1.5 0.0 5.9 42.3 56.8 -9.4 244.1 0

4-7 1 28 1.6 1.9 0.0 5.9 42.9 23.9 0.0 93.9 0

5-1 1 25 2.1 2.8 0.0 8.8 28.9 31.7 -18.8 103.3 0

5-2 1 16 0.2 2.5 -2.9 2.9 26.4 22.0 -9.4 56.3 0

5-3 1 24 -0.4 3.0 -2.9 8.8 30.5 44.0 -28.2 169 0

5-4 1 20 -0.7 2.8 -2.9 5.9 36.2 27.3 -9.4 75.1 0

5-5 1 22 1.1 1.9 0.0 5.9 38.0 22.7 0.0 75.1 0

5-6 1 20 0.9 1.4 0.0 2.9 40.8 28.3 9.4 103.3 0

5-7 1 31 0.6 1.2 0.0 2.9 4.1 20.7 -29.0 48.3 0

6-1 1 25 2.7 3.1 0.0 8.8 119.4 120.9 -9.7 425.1 0


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Exposure rate data was collected in each Survey Unit to ensure that external exposure was ALARA. All values reported are the highest gross value observed in each Survey Unit at 1m from the floor. Background throughout the building was measured between 12 – 14 µR/hr. This data is presented in Table 12-2.

Table 12-2 Exposure Rate Results

Survey Unit Class Gross Maximum Exposure Rate

(µR/hr)

1-1 1 16

1-2 1 14

1-3 1 15

1-4 1 14

1-5 1 13

1-6 1 12

1-7 1 14

2-1 1 17

2-2 1 19

2-3 1 16

2-4 1 12

2-5 1 16

Survey Unit

ClassTotal

Number

Removable Contamination(226Ra DPM/100cm2)

Total Contamination(226Ra DPM/100cm2)

Locations Exceeding

DCGLwAve. σ Min. Max. Ave. σ Min. Max.

6-2 1 27 2.4 2.9 0.0 8.8 39.4 42.3 -29.0 144.9 0

6-3 1 27 1.0 1.6 0.0 5.9 46.9 28.4 -9.7 125.6 0

6-4 1 22 1.2 2.7 0.0 8.8 36.5 22.1 9.7 77.3 0

6-5 1 22 0.4 1.0 0.0 2.9 29.4 27.4 -19.3 96.6 0

6-6 1 22 0.4 1.0 0.0 2.9 1.3 13.1 -19.3 38.6 0

6-7 1 31 0.3 0.9 0.0 2.9 15.0 25.8 -19.3 106.3 0

7-1 1 34 1.7 2.2 0.0 8.8 87.2 72.1 0.0 280.2 0

7-2 1 27 1.9 2.2 0.0 5.9 148.5 107.8 29.0 589.4 0

7-3 1 18 1.5 1.8 0.0 5.9 89.1 91.4 0.0 396.1 0

7-4 1 22 1.6 2.4 0.0 8.8 156.3 109.7 19.3 396.1 0

7-5 1 20 2.1 2.7 0.0 8.8 209.7 146.5 29.0 599.0 0

7-6 1 22 1.7 2.7 0.0 8.8 177.4 155.8 0.0 492.8 0

7-7 1 31 1.8 2.6 0.0 8.8 157.1 148.0 -9.7 579.7 0

Stairs 3 26 1.6 2.4 0.0 5.9 28.9 35.5 -9.4 131.5 0


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(µR/hr)

2-6 1 14

2-7 1 14

3-1 1 16

3-2 1 13

3-3 1 12

3-4 1 13

3-5 1 11

3-6 1 12

3-7 1 12

4-1 1 14

4-2 1 15

4-3 1 13

4-4 1 12

4-5 1 15

4-6 1 13

4-7 1 14

5-1 1 13

5-2 1 13

5-3 1 11

5-4 1 9

5-5 1 14

5-6 1 13

5-7 1 15

6-1 1 19

6-2 1 18

6-3 1 14

6-4 1 12

6-5 1 12

6-6 1 13

6-7 1 14

7-1 1 23

7-2 1 12

7-3 1 14

7-4 1 15

7-5 1 17

7-6 1 14

7-7 1 14


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(µR/hr)

Stairs 3 15

12.4 DandD Dose Calculations

To support the unrestricted release of the areas, dose calculations were completed using NRC DandD code Version 2.4. The dose was calculated using the highest average dpm total contamination value from any survey unit. Survey Unit 7-5 had the highest average dpm total contamination value. This calculated value provides a conservative estimate of dose since the other forty-nine (49) survey units have lower total contamination averages.

The calculated TEDE from 226Ra in the survey unit with the highest average measurements was calculated to be 4.7 mrem/year. The TEDE calculations are provided in Appendix F.

12.5 Decontamination Review

DDES has reviewed all of the applicable data pertaining to the history of radioactive materials use at the facility as well as the static and removable contamination surveys completed in the specified areas of Former Benrus Clock Company Site. It is our professional opinion that the areas surveyed are acceptable for unrestricted release.


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29

13.0 QUALITY ASSURANCE SURVEYS Greater than ten percent of the structural surface survey units were selected to be independently monitored to verify the reproducibility of the results recorded during final status surveys. The QA results demonstrate the data quality objectives have been met and the survey results are reproducible. QA sample data are provided in Appendix G.

ACRONYMS


January 19, 2018

ACRONYMS

ALARA As Low As Reasonably AchievableCFR Code of Federal RegulationsD&D Decontamination and DecommissioningDCGLW Derived Concentration Guideline Level DCGLEMC Elevated Measurement Exposure ConcentrationDQO Data Quality ObjectiveDSV Default Screening ValueHSA Historical Site AssessmentMARSSIM Multi-Agency Radiation Survey and Site Investigation ManualMDC Minimum Detectable ConcentrationNMSS Nuclear Materials Safety and SafeguardsNRC U.S. Nuclear Regulatory CommissionNUREG Nuclear Regulatory Commission Guidance DocumentQAPP Quality Assurance Project PlanRAM Radioactive MaterialsRSO Radiation Safety OfficerTEDE Total Effective Dose Equivalent

REFERENCES


January 19, 2018

REFERENCES

10 CFR 20, Standards for Protection Against Radiation

10 CFR 20, Subpart E., Radiological Criteria For License Termination (LTR)

NUREG-1505, “A Nonparametric Statistical Methodology for the Design and Analysis of Final Decommissioning Surveys"

NUREG 1507, “Minimum Detectable Concentrations with Typical Radiation Survey Instruments for Various Contaminants and Field Conditions”

NUREG-1575, “Multi-Agency Radiation Survey and Site Investigation Manual” (MARSSIM)

NUREG 1727, “NMSS Decommissioning Standard Review Plan,” September 2000.

NUREG-1757, Volume 1,” Consolidated NMSS Decommissioning Guidance”

NUREG 1757, Volume 2, “Consolidated NMSS Decommissioning Guidance”

U.S. Nuclear Regulatory Commission (NRC). Guidelines for the Decontamination of Facilities and Equipment Prior to Release for Unrestricted Use or Termination of Byproduct, Source, or Special Nuclear Material Licenses; Policy and Guidance Directive FC 83-23, November 1983.

U.S. Nuclear Regulatory Commission (NRC). NUREG/CR-5512, Residual Radioactive Contamination from Decommissioning, October 1992.

Abelquist, et al. 1998, Minimum Detectable Concentrations With Typical Radiation Survey Instruments for Various Contaminants and Field Conditions, NUREG-1507. Abelquist, E., W. Brown, and G. Powers, U.S. Nuclear Regulatory Commission, Washington, D.C., June 1998.

NRC 1994, NUREG-1501. Background as a Residual Radioactivity Criterion for Decommissioning. Draft Report for Comment. U.S. Nuclear Regulatory Commission, Washington, D.C., August 1994.

NRC 1998. NUREG-1505, Rev. 1. A Nonparametric Statistical Methodology for the Design and Analysis of Final Status Decommissioning Surveys. U.S. Nuclear Regulatory Commission, Washington, D.C., September 1998.


APPENDIX A

Instrument Calibration Certificates


APPENDIX B

Minimum Detectable Concentration Calculations

DDES, LLC.Analytical Worksheet

Appendix B

Minimum Detectable Concentration (MDC) Static Count

Calculations for Wipe Counter

(95% confidence level via MARSSIM method)

Where:

Eff. = Total efficiency, Counter cpm/NIST Standard dpm

Rb = LSC background rate (cpm)

Ts+b = Sample count time (minutes)

Tb = Background count time (minutes)

Static Count MDC Calculations

Isotope Eff. Rb Ts+b Tb

Tc-99 26% 37 1 10 93

Pu-239 34% 0.2 1 10 13

Minimum Detectable Concentration (MDC) Static Count

Calculations for Hand-Held Monitors

(95% confidence level via MARSSIM method)

Where: Eff. = instrument efficiency (2p geometry)

Rb = Average background rate (cpm)

Ts+b = Sample count time (minutes)

Tb = Background count time (minutes)

P = Probe area (cm2)

Eff. Rb Ts+b Tb P

Probe: 43-93

Th-230 41.4% 1.5 1 10 100 70 dpm/100 cm2

MDC (Static)

Static Count MDC Calculations

MDC (Static)

Isotope

dpm/100 cm2

dpm/100 cm2

bs

bbsbsb

TEff

TTTRcmdpmMDC

.

129.33)100/( 2

22

2

100.

129.33)100/(

cmcmareaprobeTEff

TTTRcmdpmMDC

bs

bbsbsb

Ref. MARSSIM NUREG-1575

NUREG-1507 MDC Worksheet


Appendix B

Scan Minimum Detectable Concentration (MDC)


(Scan MDA per MARSSIM/NUREG-1575, NUREG-1507 methodology)

Where: p = surveyor efficiency, per MARSSIM (0.5)

ei = instrument efficiency (2p geometry)

es = surface efficiency, 1 for gammas and high energy betas >1 Mev Emax

(e.g. P-32, Cl-36, S/Y-90, etc.), 0.5 for low energy betas

(e.g. C-14, P-33, S-35, Tc-99, Ca-45, etc.), 0.25

A = probe active area (cm2)

And,

Where:

MDCR = Minimum detectable count rate (cpm)

Si = source counts in time interval, i.

And,

Where:

d’ = 1.38 for 95% true positive scan detection rate,

per, MARSSIM, Table 6.5

Bi = Background counts in interval, i

And,

Where:

Pb = probe background count rate (cpm)

i = observation interval

secminsec60 iSMDCR i

ii BdS

sec60min1iPB bi

2100cm

Ap

MDCRMDCScan

si




Appendix B

Propagation of Error

The actual value of MDC (where ts and tb are both 1 minute), at the 95% confidence level, is:

Because most (if not all) calibration labs do not report σE ,we must compensate as shown below:

where:

σMDC = Standard deviation of Minimum Detectable Concentration, dpm/100cm2

Cb = Background counts obtained

tb = Background count time interval, minutes

Rb = Background count rate, minutes

σA = Standard deviation of calibration source activity as reported on certificate of traceability

A = Source activity, dpm, as reported on certificate of traceability

Cc = Total net sample counts (minus background counts) obtained at the

calibration facility when determining instrument efficiency

tc = Calibration facility count time interval, minutes

Rc = Calibration facility net count rate (Cc/tc)

MDCr

E

BMDC 96.1

65.43

22

ERMDC

E

b

RMDC

b

2

2

2

222

c

c

c

A

b

b

b

c

RA

b

RMDC

R

t

C

AR

t

C

MDCRAR

MDCcb




Appendix B

Scan Minimum Detectable Concentration (MDC)


(Scan MDA per MARSSIM/NUREG-1575, NUREG-1507 methodology)

Specific Scan MDC calculation results:

43-37 43-93

Electra

1A

Pb = 8 cpm Pb = 1.5 cpm Pb = 3290 cpm

i = 1 sec i = 1 sec i = 1 sec

Bi = 0.13 counts Bi = 0.03 counts Bi = 54.83 counts

d’ = 1.38 d’ = 1.38 d’ = 1.38

Si = 0.50 counts Si = 0.22 counts Si = 10.22 counts

MDCR = 30.23 cpm MDCR = 13.09 cpm MDCR = 613.13 cpm

Scan MDC Calculations

Isotope ei es A

Probe: 43-37

Th-230 42.3% 0.25 584 69 dpm/100 cm2 ± 8

Probe: 43-93

Th-230 41.4% 0.25 100 179 dpm/100 cm2 ± 21

MDC (Scan) (dpm/100cm2)




APPENDIX C

Facility Maps

1st Floor Survey Unit Overview

Former Benrus Clock Factory Radiological Characterization Survey

DDES, LLC 345 North Ave

Wakefield, MA 01880

Survey Unit 1-1

Survey Unit 1-2

Survey Unit 1-3

Survey Unit 1-4

Survey Unit 1-5

Survey Unit 1-6

Survey Unit 1-7

2nd Floor Survey Unit Overview



Wakefield, MA 01880

Survey Unit 2-1

Survey Unit 2-2

Survey Unit 2-3

Survey Unit 2-4

Survey Unit 2-5

Survey Unit 2-6

Survey Unit 2-7

3rd Floor Survey Unit Overview



Wakefield, MA 01880

Survey Unit 3-1

Survey Unit 3-2

Survey Unit 3-3

Survey Unit 3-4

Survey Unit 3-5

Survey Unit 3-6

Survey Unit 3-7

4th Floor Survey Unit Overview



Wakefield, MA 01880

Survey Unit 4-1

Survey Unit 4-2

Survey Unit 4-3

Survey Unit 4-4

Survey Unit 4-5

Survey Unit 4-6

Survey Unit 4-7




Wakefield, MA 01880

Survey Unit 5-1

Survey Unit 5-2

Survey Unit 5-3

Survey Unit 5-4

Survey Unit 5-5

Survey Unit 5-6

Survey Unit 5-7




Wakefield, MA 01880

Survey Unit 6-1

Survey Unit 6-2

Survey Unit 6-3

Survey Unit 6-4

Survey Unit 6-5

Survey Unit 6-6

Survey Unit 6-7




Wakefield, MA 01880

Survey Unit 7-1

Survey Unit 7-2

Survey Unit 7-3

Survey Unit 7-4

Survey Unit 7-5

Survey Unit 7-6

Survey Unit 7-7


APPENDIX D

Statistical Data

Mean 0.60

Standard Error 0.05

Median 0.00

Mode 0.00

Standard Deviation 2.39

Range 11.76

Max 8.82

Min -2.94

Count 1187

226Ra Removable Activity (dpm/100cm2)

Mean 42.36

Standard Error 0.05

Median 19.32

Mode 0.00

Standard Deviation 75.82

Range 628.02

Max 599.03

Min -28.99

Count 1187

226Ra Total Activity (dpm/100cm2)

Survey Unit Class Samples Type 1 Error Type 2 Error STD DEVAlpha Relative

Shift

Alpha Locations

Required

SU-1-1 1 34 0.05 0.05 29.84 26.45 14

SU-1-2 1 18 0.05 0.05 24.01 33.74 14

SU-1-3 1 27 0.05 0.05 18.24 44.84 14

SU-1-4 1 22 0.05 0.05 30.65 26.08 14

SU-1-5 1 20 0.05 0.05 21.88 37.08 14

SU-1-6 1 20 0.05 0.05 20.04 40.47 14

SU-1-7 1 31 0.05 0.05 19.15 42.66 14

SU-2-1 1 25 0.05 0.05 21.01 38.73 14

SU-2-2 1 18 0.05 0.05 24.70 32.89 14

SU-2-3 1 24 0.05 0.05 22.41 36.01 14

SU-2-4 1 22 0.05 0.05 20.47 39.51 14

SU-2-5 1 22 0.05 0.05 22.02 37.01 14

SU-2-6 1 22 0.05 0.05 12.87 63.30 14

SU-2-7 1 31 0.05 0.05 13.88 58.72 14

SU-3-1 1 22 0.05 0.05 37.10 21.26 14

SU-3-2 1 24 0.05 0.05 31.59 25.07 14

SU-3-3 1 18 0.05 0.05 34.62 22.63 14

SU-3-4 1 20 0.05 0.05 12.66 64.42 14

SU-3-5 1 22 0.05 0.05 14.81 55.70 14

SU-3-6 1 22 0.05 0.05 15.10 54.49 14

SU-3-7 1 31 0.05 0.05 16.67 49.34 14

SU-4-1 1 25 0.05 0.05 21.94 35.73 14

SU-4-2 1 25 0.05 0.05 31.19 25.18 14

SU-4-3 1 27 0.05 0.05 26.58 29.54 14

SU-4-4 1 20 0.05 0.05 56.72 13.49 14

SU-4-5 1 22 0.05 0.05 106.76 6.56 14

SU-4-6 1 20 0.05 0.05 56.79 13.68 14

SU-4-7 1 28 0.05 0.05 23.90 32.48 14

SU-5-1 1 25 0.05 0.05 31.72 24.91 14

SU-5-2 1 16 0.05 0.05 22.01 36.01 14

SU-5-3 1 24 0.05 0.05 43.98 17.93 14

SU-5-4 1 20 0.05 0.05 27.29 28.68 14

SU-5-5 1 22 0.05 0.05 22.72 34.38 14

SU-5-6 1 20 0.05 0.05 28.30 27.50 14

SU-5-7 1 31 0.05 0.05 20.69 39.39 14

SU-6-1 1 25 0.05 0.05 120.93 5.78 14

SU-6-2 1 27 0.05 0.05 42.28 18.44 14

SU-6-3 1 27 0.05 0.05 28.45 27.14 14

SU-6-4 1 22 0.05 0.05 22.10 35.41 14

SU-6-5 1 22 0.05 0.05 27.41 28.81 14

SU-6-6 1 22 0.05 0.05 13.10 62.43 14

SU-6-7 1 31 0.05 0.05 25.79 31.18 14

SU-7-1 1 34 0.05 0.05 72.09 10.15 14

SU-7-2 1 27 0.05 0.05 107.83 6.22 14

SU-7-3 1 18 0.05 0.05 91.39 7.99 14

SU-7-4 1 22 0.05 0.05 109.70 6.04 14

SU-7-5 1 20 0.05 0.05 146.47 4.16 14

SU-7-6 1 22 0.05 0.05 155.75 4.12 14

SU-7-7 1 31 0.05 0.05 147.97 4.47 14

Stairwell 3 26 0.05 0.05 35.52 22.24 Judgemental

FINAL STATUS DECONTAMINATION & CLEANUP SURVEY …4 Arrow Drive Woburn, MA 01801 JANUARY 19, 2018....

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