EPA 600/R-11/018 | April 2011 | www.epa.gov/ord 

CS Unitec ETR180 Circular 

Sander for Radiological

Decontamination 

TECHNOLOGY EVALUATION REPORT 

Office of Research and Development

National Homeland Security Research Center 
United States 

Environmental Protection

Agency 

Office of Research and 

Development 

Washington, D.C. 20460

EPA 600-R-11-018 

February 2011

www.epa.gov/nhsrc 

 

 

Technology Evaluation Report 

CS Unitec ETR180 Circular 

Sander for Radiological 

Decontamination 
EPA 600-R-11-018 

February 2011 

Technology Evaluation Report 

CS Unitec ETR 180 Circular Sander 

for Radiological Decontamination 

John Drake 

Task Order Project Officer 

National Homeland Security Research Center 

Office of Research and Development 

U.S. Environmental Protection Agency 

26 Martin Luther King Drive 

Cincinnati, OH 45268 
Disclaimer 

The U.S. Environmental Protection Agency (EPA), through its Office of Research and 

Development’s National Homeland Security Research Center, funded and managed this 

technology evaluation through a Blanket Purchase Agreement under General Services 

Administration contract number GS23F0011L-3 with Battelle. This report has been peer 

and administratively reviewed and has been approved for publication as an EPA 

document. Mention of trade names or commercial products does not constitute 

endorsement or recommendation for use of a specific product. 

Questions concerning this document or its application should be addressed to: 

John Drake 

National Homeland Security Research Center 

Office of Research and Development 

U.S. Environmental Protection Agency 

26 West Martin Luther King Dr. 

Cincinnati, OH 45268 

513-569-7164 

drake.john@epa.gov 

i 
Foreword 

The Environmental Protection Agency (EPA) holds responsibilities associated with 

homeland security events: EPA is the primary federal agency responsible for 

decontamination following a chemical, biological, and/or radiological (CBR) attack. The 

National Homeland Security Research Center (NHSRC) was established to conduct 

research and deliver scientific products that improve the capability of the Agency to carry 

out these responsibilities. 

An important goal of NHSRC’s research is to develop and deliver information on 

decontamination methods and technologies to clean up CBR contamination. When 

directing such a recovery operation, EPA and other stakeholders must identify and 

implement decontamination technologies that are appropriate for the given situation. The 

NHSRC has created the Technology Testing and Evaluation Program (TTEP) in an effort 

to provide reliable information regarding the performance of homeland security related 

technologies. TTEP provides independent, quality assured performance information that 

is useful to decision makers in purchasing or applying the tested technologies. TTEP 

provides potential users with unbiased, third-party information that can supplement 

vendor-provided information. Stakeholder involvement ensures that user needs and 

perspectives are incorporated into the test design so that useful performance information 

is produced for each of the tested technologies. The technology categories of interest 

include detection and monitoring, water treatment, air purification, decontamination, and 

computer modeling tools for use by those responsible for protecting buildings, drinking 

water supplies and infrastructure, and for decontaminating structures and the outdoor 

environment. Additionally, environmental persistence information is also important for 

containment and decontamination decisions. 

NHSRC is pleased to make this publication available to assist the response community to 

prepare for and recover from disasters involving CBR contamination. This research is 

intended to move EPA one step closer to achieving its homeland security goals and its 

overall mission of protecting human health and the environment while providing 

sustainable solutions to our environmental problems. 

Jonathan G. Herrmann, Director 

National Homeland Security Research Center 

ii 
Acknowledgments 

Contributions of the following individuals and organizations to the development of this document 

are gratefully acknowledged. 

United States Environmental Protection Agency (EPA) 

John Drake 

Emily Snyder
 

Sang Don Lee 

Lukas Oudejans 

David Musick 

Kathy Hall 

Eletha Brady-Roberts 

Jim Mitchell 

University of Tennessee 

Dr. Howard Hall 

United States Department of Energy’s Idaho National Laboratories 

Battelle Memorial Institute 

iii 
Contents 

Disclaimer........................................................................................................................................ i 

Foreword......................................................................................................................................... ii 

Acknowledgments.......................................................................................................................... iii 

Abbreviations/Acronyms ............................................................................................................... vi 

Executive Summary...................................................................................................................... vii 

1.0 Introduction...............................................................................................................................1
 

2.0 Technology Description............................................................................................................3
 

3.0 Experimental Details.................................................................................................................4
 

3.1 Experiment Preparation..................................................................................................4
 

3.1.1 Concrete Coupons ..............................................................................................4
 

3.1.2 Coupon Contamination.......................................................................................4
 

3.1.3 Measurement of Activity on Coupon Surface ....................................................5
 

3.1.4 Surface Construction Using Test Stand..............................................................6
 

3.2 Evaluation Procedures....................................................................................................6
 

4.0 Quality Assurance/Quality Control...........................................................................................8
 

4.1 Intrinsic Germanium Detector........................................................................................8
 

4.2 Audits .............................................................................................................................9
 

4.2.1 Performance Evaluation Audit ...........................................................................9
 

4.2.2 Technical Systems Audit....................................................................................9
 

4.2.3 Data Quality Audit ...........................................................................................10
 

4.3 QA/QC Reporting.........................................................................................................10
 

5.0 Evaluation Results ..................................................................................................................11
 

5.1 Decontamination Efficacy............................................................................................11
 

5.2 Deployment and Operational Factors...........................................................................13
 

6.0 Performance Summary............................................................................................................15
 

6.1 Decontamination Efficacy............................................................................................15
 

6.2 Deployment and Operational Factors...........................................................................15
 

7.0 References...............................................................................................................................16
 

iv 
Figures 

Figure 2-1. CS Unitec ETR180 (left) and sanding disk (right). ................................................... 3
 

Figure 3-1. Demonstration of contaminant application technique. .............................................. 5
 

Figure 3-2. Containment tent: outer view (left) and inner view with test stand containing 

contaminated coupons (right) .....................................................................................6
 

Figure 5-1. Test coupon surfaces before (left) and after (right) sanding with the 

ETR180.....................................................................................................................13
 

Tables 

Table 3-1. Characteristics of Portland Cement Clinker Used to Make Concrete 

Coupons ......................................................................................................................4
 

Table 4-1. Calibration Results – Difference from Th-228 Calibration Energies ........................ 8
 

Table 4-2. NIST-Traceable Eu-152 Activity Standard Check .................................................... 9
 

Table 5-1. Decontamination Efficacy Results........................................................................... 13
 

Table 5-2. Operational Factors Gathered from the Evaluation ................................................. 14
 

v 
Abbreviations/Acronyms 

ANSI 

ASTM 

BQ 

Cs 

cfm 

cm 

2

cm

DARPA 

DF 

DHS 

DOD 

EPA 

ETR180 

Eu 

HEPA 

IEEE 

INL 

keV 

kg 

mg 

mL 

L 

m 

2 m

μCi 

NHSRC 

NIST 

ORD 

%R 

RH 

PE 

QA 

QC 

QMP 

RDD 

RML 

RSD 

TSA 

TTEP 

Th 

V 

American National Standards Institute 

American Society for Testing and Materials 

Becquerel 

cesium 

cubic feet per minute 

centimeters 

square centimeters 

Defense Advanced Research Projects Agency 

decontamination factor 

U.S. Department of Homeland Security 

Department of Defense 

U.S. Environmental Protection Agency 

CS Unitec ETR180 

europium 

High Efficiency Particle Air 

Institute of Electrical and Electronics Engineers 

Idaho National Laboratory 

kilo electron volts 

kilogram 

milligram 

milliliter 

liter 

meter 

square meters 

microCurie 

National Homeland Security Research Center 

National Institute of Standards and Technology 

Office of Research and Development 

percent removal 

relative humidity 

performance evaluation 

quality assurance 

quality control 

quality management plan 

radiological dispersion device 

Radiological Measurement Laboratory 

relative standard deviation 

technical systems audit 

Technology Testing and Evaluation Program 

thorium 

volt 

vi 
Executive Summary 

The U.S. Environmental Protection Agency’s (EPA) National Homeland Security 

Research Center (NHSRC) is helping to protect human health and the environment from 

adverse impacts resulting from acts of terror by carrying out performance tests on 

homeland security technologies. Through its Technology Testing and Evaluation 

Program (TTEP), NHSRC evaluated the performance of the CS Unitec ETR180 

(hereafter referred to as the ETR180) and its ability to remove radioactive cesium (Cs)­

137 from the surface of unpainted concrete. 

Experimental Procedures. The ETR180 is a lightweight disk sander with a dust hood 

and configuration that allows sanding all the way to a wall edge. Bound Cs can be 

removed from a surface by sanding away the surface layer. Eight 15 centimeter (cm) × 15 

cm unpainted concrete coupons were contaminated with approximately 1 microCurie 

(μCi) of Cs-137 per coupon and allowed to age for seven days. The amount of 

contamination deposited on each coupon was measured using gamma spectroscopy. The 

eight contaminated coupons were placed in a test stand (along with one uncontaminated 

blank coupon) that was designed to hold nine concrete coupons in a vertical orientation to 

simulate the wall of a building. Each coupon was sanded with the ETR180, and the 

decontamination efficacy was determined by calculating both a decontamination factor 

(DF) and percent removal (%R). Important deployment and operational factors were also 

documented and reported. 

Results. The decontamination efficacy attained by the ETR180 was evaluated for each 

concrete coupon used during the evaluation. When the decontamination efficacy metrics 

(%R and DF) of the eight contaminated coupons were averaged together, the average %R 

for the ETR180 was 54 ± 10% and the average DF was 2.3 ± 0.7. Hypothesis testing was 

performed to determine if there were significant differences between the %R values 

determined for the coupons in each row (top, middle, and bottom) of the test stand. No 

differences were found. 

Following the manufacturer’s recommendations, the ETR180 was used with 24 grit 

sanding disks. The ETR180 could decontaminate a vertical surface at a rate of 

approximately 1.4 square meters (m2

) per hour with minimal surface destruction and 

minimal secondary waste. The texture of the coupon surface may be important to the 

efficacy of the ETR180 and similar radiological decontamination technologies. It was 

observed that because sanding disks do not cut into concrete surfaces, uneven concrete 

surfaces may prevent the sanding disk from reaching some areas of the concrete surfaces. 

A very limited evaluation of cross-contamination was performed. During an actual 

decontamination of a vertical surface, the higher elevation surfaces would likely be 

vii 
decontaminated first, possibly exposing the lower elevation surfaces to secondary 

contamination. To simulate an actual scenario, one uncontaminated coupon was placed 

in the bottom row of the test stand and decontaminated using the ETR180 in the same 

way as the other coupons. Following decontamination, this uncontaminated coupon did 

not exhibit measurable activity, suggesting that cross contamination was minimal. 

Overall, the vacuum shroud was effective at containing the secondary waste. There was 

very little dust visible during the evaluation and very little remaining on the floor in front 

of the test stand following the evaluation. In addition, the radiological control technicians 

did not find any measurable airborne contamination through analysis of air filters 

sampled near the test stand. The dust collected by the vacuum was not analyzed for 

gamma radiation. 

viii 
1.0 Introduction 

The U.S. Environmental Protection Agency’s (EPA) National Homeland Security 

Research Center (NHSRC) is helping to protect human health and the environment from 

adverse effects resulting from acts of terror. NHSRC is emphasizing decontamination 

and consequence management, water infrastructure protection, and threat and 

consequence assessment. In doing so, NHRSC is working to develop tools and 

information that will improve the ability of operational personnel to detect the intentional 

introduction of chemical, biological, or radiological contaminants on or into buildings or 

water systems, to contain or mitigate these contaminants, to decontaminate affected 

buildings and/or water systems, and to dispose of contaminated materials resulting from 

clean-ups. 

NHSRC, through its Technology Testing and Evaluation Program (TTEP), works in 

partnership with recognized testing organizations; stakeholder groups consisting of 

buyers, vendor organizations, and permitters; and through the participation of individual 

technology developers in carrying out performance tests on homeland security 

technologies. The program evaluates the performance of homeland security technologies 

by developing evaluation plans that are responsive to the needs of stakeholders, 

conducting tests, collecting and analyzing data, and preparing peer-reviewed reports. All 

evaluations are conducted in accordance with rigorous quality assurance (QA) protocols 

to ensure that data of known and high quality are generated and that the results are 

defensible. TTEP provides high-quality information that is useful to decision makers in 

purchasing or applying the evaluated technologies and in planning clean-up operations. 

TTEP provides potential users with unbiased, third-party information that can supplement 

vendor-provided information. Stakeholder involvement ensures that user needs and 

perspectives are incorporated into the evaluation design so that useful performance 

information is produced for each of the evaluated technologies. 

Under TTEP, NHSRC evaluated the performance of the CS Unitec (Norwalk, CT) 

ETR180 (hereafter referred to as the ETR180) in removing radioactive isotope cesium 

(Cs)-137 from concrete. A peer-reviewed test/QA plan was developed according to the 

requirements of the quality management plan (QMP) for TTEP. The evaluation generated 

the following performance information: 

Decontamination efficacy, defined as the extent of radionuclide removal following 

use of the ETR180, and the possibility of cross-contamination. 

Deployment and operational factors, including the approximate rate of surface area 

decontamination, applicability to irregular surfaces, skilled labor requirement, utility 

1 
requirements, portability, secondary waste management, and technology cost. 

This evaluation took place from August 11, 2009 until October 13, 2009. All of the 

experimental work took place in a radiological contamination area at the U.S. Department 

of Energy’s Idaho National Laboratory (INL). This report describes the quantitative 

results and qualitative observations gathered during the evaluation of the ETR180. The 

contractor, Battelle, and EPA were responsible for QA oversight. The Battelle QA 

Manager conducted a technical systems audit (TSA) during the evaluation as well as a 

data quality audit of the evaluation data. 

2 
2.0 Technology Description 

The following description of the ETR180 is based on information provided by the vendor 

and was not verified during this evaluation. 

ETR180 is a lightweight (3 kilogram, kg) circular sander with a variable speed motor, a 

dust shroud, and a configuration to allow sanding all the way to a wall edge. The ETR180 

is powered by standard 110 volt (V) electricity; according to vendor specifications, it 

operates at approximately 1,450 revolutions per minute. The handle can be adjusted for 

right- and left-handed operators. The dust shroud allows dust extraction over the brush 

rim and through the punched sanding disk and base plate. The ETR180 comes with a 

centering tool for attaching the sanding disks, which are centered for balanced and 

smooth operation. The largest sanding disk the unit can use is 18 centimeters (cm) in 

diameter. During this evaluation, the ETR180 was used with 24 grit sanding disks 

provided by the vendor. Several different disks of varying coarseness (grit density) were 

evaluated during dry runs. A blue dye was applied to the coupon surface and allowed to 

dry, after which the ETR180 was used with each disk. The 24 grit disks were chosen as 

being aggressive enough to effectively clean the surface while being only minimally 

destructive. Figure 2-1 shows the ETR180 being applied to a coupon surface during the 

dry run using a 24 grit sanding disk. 

In order to minimize the secondary waste produced during sanding, the ETR180 was 

connected to a high efficiency particulate air (HEPA) vacuum (C83985-01, Minuteman, 

Addison, IL) with a flow rate of 95 cubic feet per minute (cfm). CS Unitec did not 

provide the vacuum, but approved of its use during this evaluation. 

Figure 2-1. CS Unitec ETR180 (left) and sanding disk (right). 

3 
3.0 Experimental Details 

3.1 Experiment Preparation 

3.1.1 Concrete Coupons 

The concrete coupons were prepared from a single batch of concrete made from Type II 

Portland cement. The ready-mix company (Burns Brothers Redi-Mix, Idaho Falls, ID) 

that supplied the concrete for this evaluation provided the data which describe the cement 

clinker used in the concrete mix. For Type II Portland cement, the American Society for 

Testing and Materials (ASTM) Standard C 150-71

 specifies that tricalcium aluminate 

accounts for less than 8% of the overall cement clinker (by weight). The cement clinker 

used for the concrete coupons was 4.5% tricalcium aluminate (Table 3-1). For Type I 

Portland cement the tricalcium aluminate content should be less than 15%. Because Type 

I and II Portland cements differ only in tricalcium aluminate content, the cement used 

during this evaluation meets the specifications for both Type I and II Portland cements. 

Table 3-1. Characteristics of Portland Cement Clinker 

Used to Make Concrete Coupons 

Cement Constituent Percent of Mixture 

Tricalcium Silicate 57.6 

Dicalcium Silicate 21.1 

Tricalcium Aluminate 4.5 

Tetracalcium Aluminoferrite 8.7 

Minor Constituents 8.1 

The wet concrete was poured into 0.9 meter (m) square plywood forms with the exposed 

surface “floated” to allow the smaller aggregate and cement paste to float to the top, and 

the concrete was then cured for 21 days. Following curing, the squares were cut to the 

desired size with a laser-guided rock saw. For this evaluation, the “floated” surface of the 

concrete coupons was used. The coupons were approximately 4 cm thick, 15 cm × 15 cm 

square, and had a surface finish that was consistent across all the coupons. The concrete 

was representative of exterior concrete commonly found in urban environments in the 

United States as shown by INL under a previous project sponsored by the U.S. 

Department of Defense (DOD), Defense Advanced Research Projects Agency (DARPA) 

and U.S. Department of Homeland Security (DHS).2 

3.1.2 Coupon Contamination 

4 
Eight coupons were contaminated by spiking individually with 2.5 milliliters (mL) of 

aqueous solution that contained 0.26 milligrams (mg)/liter (L) Cs-137 as a solution of 

cesium chloride, corresponding to an activity level of approximately 1 microCurie (μCi) 

over the 225 square centimeters (cm2) surface. Application of the Cs-137 in an aqueous 

solution was justified because even if Cs-137 were dispersed in a particle form following 

a radiological dispersion device (RDD) or “dirty bomb” event, morning dew or rainfall 

would likely occur before the surfaces could be decontaminated. In addition, from an 

experimental standpoint, it is much easier to apply liquids, rather than dry particles, 

homogeneously across the surface of the concrete coupons. The liquid spike was 

delivered to each coupon using an aerosolization technique developed by INL (under a 

DARPA/DHS project4) and described in detail in the test/QA plan. The coupons were 

then allowed to age for seven days. 

The aerosol delivery device was constructed of two syringes. The plunger and needle 

were removed from the first syringe and discarded. Then, a compressed air line was 

attached to the rear of the syringe. The second syringe contained the contaminant solution 

and was equipped with a 27 gauge needle, which penetrated through the plastic housing 

near the tip of the first syringe. Compressed air flowing at a rate of approximately 1 - 2 L 

per minute created a turbulent flow through the first syringe. When the contaminant 

solution in the second syringe was introduced, the solution became nebulized by the 

turbulent air flow. A fine aerosol was ejected from the tip of the first syringe, creating a 

controlled and uniform spray of fine liquid droplets onto the coupon surface. The 

contaminant spray was applied all the way to the edges of the coupon, which were taped 

(after having previously been sealed with polyester resin) to ensure that the contaminant 

was applied only to the surfaces of the coupons. The photographs in Figure 3-1 show this 

procedure being performed using a nonradioactive, nonhazardous aqueous dye to 

demonstrate that the 2.5 mL of contaminant solution is effectively distributed across the 

surface of the coupon. 

Figure 3-1. Demonstration of contaminant application technique. 

3.1.3 Measurement of Activity on Coupon Surface 

Gamma radiation from the surface of each concrete coupon was measured to quantify 

contamination levels both before and after evaluation of the ETR180. These 

measurements were made using an intrinsic, high purity germanium detector (Canberra 

LEGe Model GL 2825R/S, Meriden, CT). After being placed in the detector, each 

5 
coupon was measured until the average activity level of Cs-137 from the surface 

stabilized to a relative standard deviation of less than 2%. Gamma-ray spectra acquired 

from Cs-137 contaminated coupons were analyzed using INL Radiological Measurement 

Laboratory (RML) data acquisition and spectral analysis programs. Radionuclide 

activities on coupons were calculated based on efficiency, emission probability, and halflife values. Decay corrections were made based on the date and the duration of the 

counting period. Full RML gamma counting QA/quality control (QC), as described in 

the test/QA plan, was employed and certified results were provided. 

3.1.4 Surface Construction Using Test Stand 

To evaluate the decontamination technologies on vertical surfaces (simulating walls), a 

stainless steel test stand was fabricated that held three rows of three concrete coupons. 

The test stand, approximately 9 feet (ft) × 9 ft, was erected within a containment tent. The 

concrete coupons were placed into holders so their surfaces extended just beyond the 

surface of the stainless steel face of the test stand. Eight of the nine coupons placed in the 

test stand were contaminated with Cs-137, which has a half-life of 30 years. One 

uncontaminated coupon was placed in the bottom row of the test stand and 

decontaminated using the ETR180 in the same way as the other coupons. This coupon 

was placed on the test stand to observe possible secondary contamination caused by the 

decontamination process being conducted higher on the wall. Figure 3-2 shows the 

containment tent and the test stand loaded with the concrete coupons. 

Figure 3-2. Containment tent: outer view (left) and inner view with test stand 

containing contaminated coupons (right). 

3.2 Evaluation Procedures 

The containment tent consisted of two rooms. One room contained the test stand to hold 

the contaminated coupons; the other room (the shorter part of the tent as shown in Figure 

3-2) held the vacuum. An opening in the tent wall between the two rooms was just large 

enough to allow the vacuum hose connected to the ETR180 to pass through. The tent 

opening was taped closed around the hose prior to the start of the evaluation. 

6 
The nine concrete coupons in the test stand were sanded using the ETR180 starting with 

the top row and working from left to right, then proceeding to the middle and bottom 

rows. The coupons were sanded in this manner to simulate an approach that would likely 

be taken in an actual decontamination event, where higher wall surfaces would be 

decontaminated first because of the possibility of secondary contamination lower on the 

wall. The ETR180 was connected to the vacuum and used at full power for one minute on 

each coupon. The temperature and relative humidity (RH) were recorded before (21.1°C, 

32% RH) and after (21.4°C, 32% RH) the approximately one hour test. These conditions 

did not vary significantly in the room where the evaluation was performed. 

7 
4.0 Quality Assurance/Quality Control 

QA/QC procedures were performed in accordance with the program QMP and the 

test/QA plan for this evaluation. 

4.1 Intrinsic Germanium Detector 

The germanium detector was calibrated once each week. The calibration was performed 

in accordance with standardized procedures from the American National Standards 

Institute (ANSI) and the Institute of Electrical and Electronics Engineers (IEEE).3

 In 

brief, detector energy was calibrated using thorium (Th)-228 daughter gamma rays at 

238.6, 583.2, 860.6, 1620.7, and 2614.5 kilo electron volts (keV). This calibration was 

performed three times during the overall project and documented by the RML. Table 4-1 

gives the difference between the known energy levels and those measured following 

calibration. The energies were compared to the previous 30 calibrations to confirm that 

the results were within three standard deviations of the previous calibration results. All 

the calibrations fell within this requirement. 

Table 4-1. Calibration Results – Difference from Th-228 Calibration Energies 

Calibration Energy Levels (keV) 

Energy 1 Energy 2 Energy 3 Energy 4 Energy 5

Date 238.632 583.191 860.564 1620.735 2614.533 

8-25-2009 -0.005 0.014 -0.031 -0.199 0.031 

9-21-2009 -0.003 0.009 -0.040 -0.125 0.015 

10-13-2009 -0.003 0.008 -0.011 -0.180 0.020 

Gamma ray counting was continued on each coupon until the activity level of Cs-137 on 

the surface had a relative standard deviation (RSD) of less than 2%. This RSD occurred 

within the initial 1 hour of counting for all the coupons measured during this evaluation. 

The final activity assigned to each coupon was a compilation of information obtained 

from all components of the electronic assemblage that comprise the "gamma counter," 

including the raw data and the spectral analysis described in Section 3.1.3. Final spectra 

and all data that comprise the spectra were sent to a data analyst who independently 

confirmed the "activity" number arrived at by the spectroscopist. When both the 

spectroscopist and an expert data analyst independently arrived at the same value the data 

were considered certified. This process defines the full gamma counting QA process for 

certified results. 

8 
The background activity of the concrete coupons was determined by analyzing nine 

arbitrarily selected coupons from the stock of concrete coupons used for this evaluation. 

The ambient activity level of these coupons was measured for at least two hours. No 

activity was detected above the minimum detectable level of 2×10-4 μCi on these 

coupons. Because the background activity was not detectable (and the detectable level 

was more than 2,500 times lower than the post-decontamination activity levels), no 

background subtraction was required. 

Throughout the evaluation, a second measurement was taken on 10 coupons in order to 

provide duplicate measurements to evaluate the repeatability of the instrument. Half of 

the duplicate measurements were performed after contamination prior to application of 

the decontamination technology and half were performed after decontamination. Five of 

the duplicate pairs showed no difference in activity levels between the two 

measurements; the other five duplicate pairs had a difference of 2% between the two 

measurements, within the acceptable difference of 5%. 

4.2 Audits 

4.2.1 Performance Evaluation Audit 

RML performed regular checks of the accuracy of the Th-228 daughter calibration 

standards (during the time when the detector was in use) by measuring the activity of a 

National Institute of Standards and Technology (NIST)-traceable europium (Eu)-152 

standard (in units of Becquerel, BQ) and comparing it to the accepted NIST value. 

Results within 7% of the NIST value are considered to be within acceptable limits. The 

Eu-152 activity comparison is a routine QC activity performed by INL, but for the 

purposes of this evaluation serves as the performance evaluation (PE) audit, an audit that 

confirms the accuracy of the calibration standards used for the instrumentation critical to 

the results of an evaluation. Table 4-2 gives the results of each of the audits applicable to 

the duration of the evaluation. All results are below the acceptable difference of 7%. 

Table 4-2. NIST-Traceable Eu-152 Activity Standard Check 

Relative 

NIST Activity INL RML Percent 

Date (BQ) Result (BQ) Difference 

8-18-2009 124,600 122,400 2% 

9-10-2009 124,600 122,600 2% 

10-12-2009 124,600 122,300 2% 

4.2.2 Technical Systems Audit 

A TSA was conducted during testing at INL to ensure that the evaluation was performed 

in accordance with the test/QA plan and the TTEP QMP. As part of the audit, the actual 

evaluation procedures were compared with those specified in the test/QA plan and the 

data acquisition and handling procedures were reviewed. No significant adverse findings 

9 
were noted in this audit. The records concerning the TSA are stored indefinitely with the 

Battelle QA Manager. 

4.2.3 Data Quality Audit 

The Battelle QA Manager verified all of the raw data acquired during the evaluation and 

transcribed into spreadsheets for use in the final report. The data were traced from the 

initial raw data collection, through reduction and statistical analysis, to final reporting, to 

ensure the integrity of the reported results. 

4.3 QA/QC Reporting 

Each assessment and audit was documented in accordance with the test/QA plan and the 

QMP. The Battelle QA Manager prepared the draft assessment report and sent it to the 

Test Coordinator and Battelle TTEP Program Manager for review and approval. The 

Battelle QA Manager then sent the final assessment report to the EPA QA Manager and 

Battelle staff. 

10 
5.0 Evaluation Results 

5.1 Decontamination Efficacy 

The decontamination efficacy of the ETR180 was measured for each contaminated 

coupon in terms of percent removal (%R) and decontamination factor (DF). Both of these 

measurements provide a means of representing the extent of decontamination 

accomplished by a technology. The %R gives the extent of removal as a percent relative 

to the activity and the DF is the ratio of the initial activity to the final activity or the 

factor by which the activity was decreased. These terms are defined by the following 

equations: 

%R = (1-Af/Ao) × 100% and DF = Ao/Af 

where Ao is the radiological activity from the surface of the coupon before application of 

the ETR180 and Af is radiological activity from the surface of the coupon after treatment. 

While the DFs are reported, the narrative describing the results focuses on the %R. 

Table 5-1 gives the %R and DF for the ETR180. All coupons were oriented vertically. 

The target activity for each of the contaminated coupons (pre-decontamination) was 

within the acceptable range of 1 μCi ± 0.5 μCi. The overall average (plus or minus one 

standard deviation) of the contaminated coupons was 1.15 μCi ± 0.07 μCi, a variability of 

6%. The post-decontamination coupon activities were less than the pre-decontamination 

activities showing an overall reduction in activity. The %R averaged 54 ± 10% and the 

DF averaged 2.3 ± 0.7. Overall, the %R ranged from 42% to 74% and the DF ranged 

from 1.7 to 3.9. The coupons with the %R values of 61% and 74% were notably higher 

than the %R values for the other six coupons, which all fell within the range of 42% to 

53%. There was no obvious reason for these larger %R values. 

Paired t-tests were performed at a 95% confidence interval to determine whether location 

(top, middle, or bottom) on the test stand affected the decontamination efficacy. While 

the average %R for the top row (47% ± 5%) of coupons was slightly lower than the 

middle (58% ± 14%) and bottom (57% ± 6%) rows, no significant difference between 

any of the rows was found. The bottom middle coupon was not contaminated to test the 

possibility of cross-contamination. Activity of the uncontaminated coupon was measured 

after the ETR180 had been used on all nine coupons. No activity was detected on the 

uncontaminated coupon, suggesting that cross-contamination resulting from ETR180 

sanding was minimal. 

11 
12 
Table 5-1. Decontamination Efficacy Results 

Coupon 

Location in Pre-Decon Activity Post-Decon Activity 

Test Stand μCi / Coupon μCi / Coupon %R DF 

Top left 1.12 0.53 53 2.1 

Top middle 1.21 0.71 42 1.7 

Top right 1.21 0.64 47 1.9 

Center left 1.06 0.53 50 2.0 

Center middle 1.12 0.57 50 2.0 

Center right 1.13 0.29 74 3.9 

Bottom left 1.09 0.52 52 2.1 

Bottom right 1.25 0.48 61 2.6 

Average 1.15 0.53 54 2.3 

Std. Dev 0.07 0.12 10 0.7 

5.2 Deployment and Operational Factors 

A number of operational factors were documented by the ETR180 operator. One of the 

factors was damage to the surface of the concrete coupons. Figure 5-1 shows photographs 

of an uncontaminated coupon before and after sanding with the ETR180. The slight pink 

color is due to a dye that was applied to the surface of the noncontaminated coupon for 

illustrative purposes. The coupon on the right still has all of the obvious surface 

characteristics (discolorations, etc.) visible on the coupon on the left. However, a very 

thin layer of the surface (referred to as the “cream” of the concrete) has been removed as 

a result of sanding with the ETR180 making those characteristics more pronounced on 

the right coupon. The ETR180 operator referred to the condition of the right coupon as 

looking “polished.” It is clear from these photographs that a small amount of the surface 

was removed, but not enough to significantly change the look of the coupon. 

Figure 5-1. Test coupons before (left) a 

after (right) sanding with the ETR180. 

Another important factor to consider is the personal protection of the technology 

operators. During this evaluation, the radiological control technicians required the 

operators to wear full anti-contamination personal protective equipment that included a 

full face respirator with supplied air. This level of personal protection was required by 

the INL RCTs because of the likelihood of airborne radiological contamination due to the 

nd 

13 
act of sanding. However, each situation will need to be considered independently by 

local RCTs to determine the proper level of personal protection. 

Table 5-2 summarizes qualitative and quantitative practical information gained by the 

operator during the evaluation of the ETR180. All of the operational information was 

gathered during use of ETR180 on the concrete coupons inserted into the test stand. 

Some of the information given in Table 5-2 could differ if the ETR180 were applied to a 

larger surface or to a surface that was smoother or more rough and jagged than the 

concrete coupons used during this evaluation. 

Table 5-2. Operational Factors Gathered from the Evaluation 

Parameter Description/Information 

Decontamination 

rate 

Technology Preparation: 15 minutes to attach sanding disk, vacuum shroud, and 

vacuum to the ETR180. 

Application: One minute per concrete coupon used during this evaluation corresponds 

to an application rate of 1.4 m2

/hour; less or more time per coupon may result in 

different levels of radiological decontamination. 

Applicability to 

irregular surfaces 

Application to irregular surfaces could be problematic for sanding disk technologies 

like the ETR180 because the rotating disk does not cut into the surface of the 

concrete: therefore, irregular coupon surfaces may prevent the sanding disk from 

reaching some areas of the coupons. 

Skilled labor 

requirement 

The rotating sanding disk is an extremely basic technology requiring minimal 

training. Adequate training would likely include a few minutes of orientation so the 

operator is familiar with the power switches on the vacuum and the ETR180. The 

ETR180 centering tool was helpful in attaching the sanding disks. 

The ETR180 weighs 3 kg. The operator during this evaluation experienced a 

significant level of exertion as he completed the evaluation. The weight of the 

ETR180, in combination with the additional weight and awkwardness of the attached 

HEPA vacuum hose, increased the level of effort required to use the ETR180 when 

standing on a ladder holding the ETR180 at a level equivalent to the operator’s chest. 

These factors will exclude some people from operating the ETR180. However, most 

people who are used to performing physical labor should not have any problem 

operating the ETR180. 

Utilities 

requirement 110V power for both the ETR180 and an applicable vacuum. 

Extent of portability The limiting factors of portability for the ETR180 will include the availability of 

power and the ability to connect to the vacuum by staying close enough to the 

vacuum or by having vacuum hosing of adequate length. 

Sanding media A new sanding disk was used after treating every 5 concrete coupons. The 24 grit 

surface became smoother after each successive sanding. 

Secondary waste 

management 

The vacuum shroud was effective at containing the secondary waste. There was very 

little dust visible during the evaluation and very little remaining on the floor in front 

of the test stand following the evaluation. In addition, the radiological control 

technicians did not find any measurable airborne contamination during the evaluation. 

The dust collected by the vacuum was not analyzed for gamma radiation, but given 

the decrease in activity on the coupons, the waste would have had measurable 

activity. 

Surface damage Operator described surface as being “polished.” See description and photograph in 

text. 

Cost The cost of ETR 180 is $389 and replacement disks are less than $5 each. 

14 
6.0 Performance Summary 

This section presents the findings from the evaluation of the ETR180 for each 

performance parameter evaluated. 

6.1 Decontamination Efficacy 

The decontamination efficacy (in terms of %R) attained by the ETR180 was evaluated 

for each concrete coupon used during the evaluation. When the decontamination efficacy 

metrics (%R and DF) of the eight contaminated coupons were averaged together, the 

average %R for the ETR180 was 54 ± 10% and the average DF was 2.3 ± 0.7. Hypothesis 

testing was performed to determine if there were significant differences between the %R 

values determined for the coupons in each row (top, middle, and bottom) of the test stand. 

No differences were found. 

6.2 Deployment and Operational Factors 

Following the manufacturer’s recommendations, the ETR180 was used with 24 grit 

sanding disks. The ETR180 could decontaminate a vertical surface at a rate of 

approximately 1.4 m2 per hour with minimal surface destruction and minimal secondary 

waste. The texture of the coupon surface may be important to the efficacy of the ETR180 

and similar radiological decontamination technologies. Battelle observed that because 

sanding disks do not cut into concrete surfaces, uneven concrete surfaces may prevent the 

sanding disk from reaching some areas of the concrete surfaces. 

A limited evaluation of cross-contamination was performed. During an actual 

decontamination of a vertical surface, the higher elevation surfaces would likely be 

decontaminated first, possibly exposing the lower elevation surfaces to secondary 

contamination. To simulate an actual scenario, one uncontaminated coupon was placed 

in the bottom row of the test stand and decontaminated using the ETR180 in the same 

way as the other coupons. Following decontamination, this uncontaminated coupon did 

not exhibit measurable activity, suggesting that cross contamination was minimal. 

Overall, the vacuum shroud was effective at containing the secondary waste. There was 

very little dust visible during the evaluation and very little remaining on the floor in front 

of the test stand following the evaluation. In addition, the radiological control technicians 

did not find any measurable airborne contamination through analysis of air filters 

sampled near the test stand. The dust collected by the vacuum was not analyzed for 

gamma radiation. 

15 
7.0 References 

1.	 ASTM Standard C 150-07, “Standard Specification for Portland Cement.” ASTM 

International, West Conshohocken, PA, www.astm.org, 2007, 

2.	 Radionuclide Detection and Decontamination Program. Broad Agency 

Announcement 03-013, U.S. Department of Defense (DOD) Defense Advanced 

Research Projects Agency (DARPA) and the U.S. Department of Homeland Security, 

classified program. 

3.	 Calibration and Use of Germanium Spectrometers for the Measurement of Gamma 

Emission Rates of Radionuclides. American National Standards Institute. ANSI 

N42.14-1999. IEEE New York, NY (Rev. 2004). 

16 
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