EPA 600/R-11/015 | May 2011 | www.epa.gov/ord

Office of Research and Development

National Homeland Security Research Center

River Technologies LLC 3-Way 

Decontamination System for 

Radiological Decontamination

Technology evaluaTion RepoRT
 EPA 600-R-11-015

May 2011

Technology Evaluation Report

River Technologies LLC 3-Way 

Decontamination System for 

Radiological Decontamination 

United States Environmental Protection Agency 

Cincinnati, OH 45268
ii

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 
iii

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 Herrmann, Director 

National Homeland Security Research Center
iv

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

Howard Hall

United States Department of Energy’s Idaho National Laboratories 

Battelle Memorial Institute
v 

Contents

Foreword ............................................................................................................................ iii

Acknowledgments.............................................................................................................. iv

Abbreviations/Acronyms .................................................................................................. vii

Executive Summary......................................................................................................... viii

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...................................................................10

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 ...................................................................12

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

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

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

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

Figures

Figure 2-1. 3WDS rotating spray tool (left). 3WDS vacuum canister and waste 

collection drum (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 3-3. Operator applying 3WDS to concrete coupon. ...........................................................7

Figure 5-1. Water running onto other coupons ............................................................................12

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 ............................................................................12

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

Abbreviations/Acronyms

3WDS

ANSI

ASTM

BQ

Cs

cfm

cm

cm2

River Technologies, LLC 3-Way Decontamination System

American National Standards Institute

American Society for Testing and Materials

Becquerel

cesium

cubic feet per minute 

centimeters

square centimeters

DARPA Defense Advanced Research Projects Agency

DF decontamination factor

DHS U.S. Department of Homeland Security

DOD Department of Defense

EPA

Eu

Ft

IEEE

INL

U.S. Environmental Protection Agency

europium 

feet

Institute of Electrical and Electronics Engineers

Idaho National Laboratory

keV

mg

mL

L 

m 

m

2

μCi

kilo electron volts

milligram

milliliter

liter

meter

square meters

microCuries

NHSRC

NIST

National Homeland Security Research Center

National Institute of Standards and Technology

ORD Office of Research and Development

%R percent removal

PE

psi

performance evaluation

pounds per square inch

QA quality assurance

QC quality control

QMP

RDD

RH

quality management plan

radiological dispersion device 

relative humidity

RML

RSD

Radiological Measurement Laboratory

relative standard deviation

TSA technical systems audit

TTEP

Th

Technology Testing and Evaluation Program

thorium

V volt
viii

Executive Summary

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

Research Center (NHSRC) Technology Testing and Evaluation Program (TTEP) 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. Under 

TTEP, Battelle evaluated the performance of the River Technologies, LLC 3-Way 

Decontamination System (hereafter referred to as the 3WDS), and its ability to remove 

radioactive Cs-137 from the surface of unpainted concrete. 

Experimental Procedures. The 3WDS is designed to clean floors, walls, and surfaces 

contaminated with loose or fixed radioactive debris by using a high pressure/hot water 

sprayer and an air-powered vacuum recovery system. The 3WDS consists of a pressure 

washer spray tool equipped with rotating spray nozzles enclosed by a vacuum shroud. 

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 treated using 

the 3WDS, 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 3WDS was evaluated for each 

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

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

for the 3WDS was 36% ± 4% and the average DF was 1.58 ± 0.09. 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.

The rate at which the 3WDS could be used to decontaminate a vertical surface was 

approximately 5.4 square meters (m2

) per hour. The 3WDS caused no visible surface 

destruction of the coupons. Approximately 40 liters (L) of secondary liquid waste was 

generated during application. The texture of the concrete surface is not likely to be 

important to the efficacy of the 3WDS and similar water blasting radiological 

decontamination technologies. The high pressure water should access most concrete 

surfaces, regardless of the irregularities. The 3WDS was used with a gas-powered, dieselheated high pressure hot water washer. In addition, the vacuum recovery system required 

an air compressor to provide at least 250 cubic feet per minute (cfm) of air flow at a 

pressure of 120 pounds per square inch (psi). A large diesel powered air compressor was 

used during this evaluation to power the 3WDS vacuum. With two sources of power 

required the locations at which the 3WDS can be used could be limited. 
ix

A very 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 3WDS in the same way as 

the other coupons. Following decontamination, the uncontaminated coupon exhibited a 

very small but measurable activity (0.0019 μCi compared with approximately 0.7 μCi on 

the coupons that had been decontaminated), suggesting that minimal cross contamination 

had occurred in the process of decontaminating the other coupons and this coupon using 

the 3WDS. In addition, the 3WDS created a significant amount of mist around the spray 

tool. This mist caused the operator’s outer layer of protective gear to become very wet. 

The possibility of contaminating the operator with secondary waste would likely be a 

safety concern in an actual decontamination operation.
1 

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’s 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 vendorprovided 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, Battelle evaluated the

performance of the River Technologies

(Forest, VA), LLC 3-Way 

Decontamination System (hereafter 

referred to as the 3WDS) in removing 

radioactive isotope Cs-137 from concrete. 

Battelle followed a peer-reviewed test/QA 

plan that was developed according to the 

requirements of the quality management 

plan (QMP) for TTEP. The evaluation 

generated the following performance 

information for the 3WDS: 

Decontamination efficacy, defined as 

the extent of radionuclide removal 

following use of the 3WDS, and the 

possibility of cross-contamination. 

Deployment and operational data, 

including rate of surface area 

decontamination, applicability to 

irregular surfaces, skilled labor 

requirement, utility requirements, 

portability, secondary waste 

management, and technology cost.
2 

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 

this evaluation of the 3WDS. 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. 
3 

2.0 Technology Description

The following description of the 3WDS is

based on information provided by the 

vendor and was not verified during this 

evaluation. 

The 3WDS consists of a pressure washer 

spray tool equipped with rotating spray 

nozzles enclosed by a vacuum shroud. 

The spray tool is attached to a gaspowered, diesel-heated high pressure hot 

water washer (Mi-T-M, Peosta, IA; Model 

HSP-3504-3), capable of providing 

pressures of up to 3,500 pounds per 

square inch (psi) and water at 180 oF. 

During this evaluation the unit was 

attached to a compressed air powered 

vacuum (Nederman, Helsingborg, 

Sweden; Model NE52), which requires 

approximately 250 cubic feet per minute 

(cfm) of air at approximately 120 psi. A 

diesel-powered air compressor (LeROI, 

Sidney, OH; Model 260) was used to 

provide the compressed air to operate the 

vacuum necessary for recovery of the 

water. The air compressor was available at 

the test location and the pressure washer 

was rented for the duration of testing. 

Figure 2-1 shows photographs of the 

3WDS spray tool and vacuum used during 

the evaluation. The metal surrounding the 

rotating spray nozzles serves as a vacuum 

shroud to collect the sprayed water. 

Figure 2-1. 3WDS rotating spray tool (left). 3WDS vacuum canister and waste 

collection drum (right). 
4 

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.1 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 

account 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 centimeters (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 

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 centimeter (cm2

) surface. 

Application of the Cs in an aqueous 

solution was justified because even if Cs

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, 
5 

it is much easier to apply liquids, rather 

than 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 

project2

) 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 3WDS. These 

measurements were made using an

intrinsic, high purity germanium detector 

(Canberra LEGe Model GL 2825R/S, 

Meriden, CT). After being placed into the 

detector, each 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 half-life 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. 
6 

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 3WDS in 

the same way as the other coupons. This 

coupon was placed there to observe 

possible secondary contamination caused 

by the decontamination 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 3WDS 

vacuum and collection drum. The vacuum 

hose extending from the collection drum 

connected to the vacuum shroud on the 

spray tool through a small opening in the 

tent wall between the two rooms. The 

power washer and air compressor were 

located outside the containment tent. The 

high pressure water hose connected to the 

spray tool through a small opening in the 

outer tent wall, and traveled through the 

smaller room and into the test stand room 

through a small opening in the tent wall 

between the two rooms. Each of the tent 

openings was taped closed around the 

hoses. Figure 3-3 shows the metal tube 

providing the high pressure water through 

the top of the spray tool and the larger 

diameter vacuum hose connecting to the 

vacuum shroud (which surrounds the 

spray tool) as the operator applies the 

3WDS to a concrete coupon. 

The nine concrete coupons in the test 

stand were pressure washed with the 

3WDS starting with the top row and 

working from left to right, then 

proceeding to the middle and bottom 

rows. The coupons were sprayed 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 
7 

because of the possibility of secondary 

contamination lower on the wall. 

The flow of hot, pressurized water was 

initiated by hand triggering the spray tool; 

the vacuum flow was continuous 

(controlled by a valve near the vacuum 

canister). Upon triggering, there was 

approximately a two second delay before 

the water flowed at full strength and 

caused the nozzles to rotate. Each coupon 

was then sprayed for approximately 15 

seconds, moving the tool back and forth to 

ensure that the entire surface of the 

coupon had been covered. The trigger was 

released between coupons to stop the flow 

of water. This application technique 

would correspond to a rate of 0.1 square 

meters (m2

) per minute. The temperature 

and relative humidity (RH) were recorded 

before (17.5 °C, 32% RH) and after (18.6 

°C, 32% RH) the approximately one hour 

test. These conditions did not vary 

significantly in the room where the 

evaluation was performed. 

Figure 3-3. Operator applying 3WDS to concrete coupon.
8 

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 throughout the 

evaluation 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. The calibrations are 

shown for the detector used during this 

evaluation. All the calibrations fell within

this requirement.

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

Date

Calibration Energy Levels (keV)

Energy 1 

238.632

Energy 2 

583.191

Energy 3 

860.564

Energy 4

1620.735

Energy 5 

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 Cs137 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, 

then the data were considered certified. 

This process defines the full gamma 

counting QA process for certified results. 

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 postdecontamination activity levels), no 

background subtraction was required. 
9 

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 this activity 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 this activity comparison 

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 evaluation. All of the 

measurements during this evaluation were 

made during three separate weeks. 

Therefore, there are three sets of results 

and all results are within the acceptable 

difference of 7%.

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

Date

NIST Activity 

(BQ) 

INL RML 

Result (BQ)

Relative 

Percent 

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%
10 

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 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.
11 

5.0 Evaluation Results

5.1 Decontamination Efficacy 

The decontamination efficacy of the 

3WDS 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 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 3WDS 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 

3WDS. All coupons were oriented 

vertically. The target activity for each of 

the contaminated coupons (predecontamination) 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 1.13 μCi ± 0.03 μCi, a 

variability of 3%. The postdecontamination coupon activities were 

less than the pre-decontamination 

activities showing an overall reduction in 

activity. The %R (calculated as described 

above) averaged 36% ± 4% and the DF 

averaged 1.58 ± 0.09. Overall, the %R 

ranged from 31% to 43% and the DF 

ranged from 1.46 to 1.76. 

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. No significant difference 

between any of the rows was determined.

The bottom middle coupon was not 

contaminated to test the possibility of 

cross-contamination. Activity of the 

uncontaminated coupon was measured 

after the 3WDS had been applied to all 

nine coupons. During application of the 

3WDS to the coupons located higher on 

the test stand, droplets of water that had 

been sprayed onto the coupons (but not 

collected by the vacuum) ran down the 

test stand onto the coupons below as

shown in Figure 5-1. Following the 

application of the 3WDS to all nine 

coupons, including the uncontaminated 

coupon, the uncontaminated coupon 

exhibited a very small but measurable 

activity (0.0019 μCi compared with 1 μCi

on the contaminated coupons), suggesting 

that some cross contamination had 

occurred during the application of the 

3WDS. 
12 

Table 5-1. Decontamination Efficacy Results

Coupon 

Location in 

Test Stand

Pre-Decon Activity 

μCi / Coupon

Post-Decon Activity 

μCi / Coupon %R DF

Top left 1.14 0.781 31 1.46

Top middle 1.18 0.769 35 1.53

Top right 1.15 0.730 37 1.58

Center left 1.09 0.619 43 1.76

Center middle 1.12 0.699 38 1.60

Center right 1.11 0.734 34 1.51

Bottom left 1.17 0.757 35 1.55

Bottom right 1.10 0.678 38 1.62

Average 1.13 0.72 36 1.58

Std. Dev 0.03 0.05 4 0.09

5.2 Deployment and Operational 

Factors 

A number of operational factors were 

documented by the 3WDS operator. One 

of the factors was damage to the surface 

of the concrete coupons. The 3WDS used 

pressurized hot water to remove 

radiological contamination from the 

surface of the concrete coupons. The 

water pressures and spray nozzles used 

did not cause any visible surface removal 

of concrete. The hot, high pressure water 

spray combined with the vacuum to clean 

the surface of the concrete coupons of all 

loose particles and dirt, but did not cause 

visible surface damage.

Another important factor to consider is the 

secondary waste management of a 

decontamination technology and the 

personal protection of the technology 

operators. During this evaluation, the 

radiological control technicians required 

the operators to wear full anticontamination personal protective 

equipment that included a full face 

respirator with supplied air. The 3WDS 

created a significant amount of mist 

around the spray tool that caused water to 

run down the test stand and caused the 

operator’s outer layer of protective gear to 

become very wet. The possibility of 

contaminating the operators with 

secondary waste or the ground 

surrounding the surface being 

contaminated with liquid radiological 

waste may be a major concern in an actual 

decontamination event. These concerns 

were also present during this evaluation, 

but the radiological control technicians 

who oversaw the evaluation determined 

that no measureable cross-contamination 

occurred due to the water from the 3WDS. 
13 

Figure 5-1. Water running 

onto other coupons. 

Table 5-2 summarizes qualitative and 

quantitative practical information gained 

by the operator during the evaluation of 

the 3WDS. All of the operational 

information was gathered during use of 

3WDS on the concrete coupons inserted 

into the test stand. Some of the 

information given in Table 5-2 could 

differ if the 3WDS were applied to a 

larger surface or surfaces made up of 

different types of concrete.
14 

Table 5-2. Operational Factors Gathered from the Evaluation 

Parameter Description/Information

Decontamination 

rate 

Technology Preparation: Upon initial receipt, it took 1.5 days to get the components 

assembled and the spray tool to function properly. 

Application: Approximately 15 seconds per concrete coupon corresponds to an 

application rate of 5.4 m2

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

levels of radiological decontamination.

Applicability to 

irregular surfaces

Irregular surfaces should not be a problem for the 3WDS as the high pressure water 

should be able to access most concrete surfaces, regardless of the roughness. 

Skilled labor 

requirement

Adequate training would likely require approximately one hour. In addition to the 

assembly and operation of the 3WDS, topics would need to include safety precautions 

unique to pressurized water spray and 3WDS troubleshooting. 

The 3WDS spray tool alone is not heavy, but the operator experienced a significant 

level of exertion as he completed the evaluation. The weight of the 3WDS, in 

combination with the additional weight and awkwardness of the attached water and 

vacuum hoses, increased the level of effort required to use the 3WDS. Depending on 

what row of the test stand is being used, the operator was required to bend over, stand 

on the floor, or stand on a ladder. Each of these situations required a significant 

amount of exertion. These factors will exclude some people from operating the 

3WDS. However, most people who are used to performing physical labor should not 

have any problem operating the 3WDS.

Utilities required 250 cfm compressed air at 120 psi and hot, high pressure water are the two 

requirements for operation. 

Portability The limiting factors of portability for the 3WDS will include the availability of 250

cfm compressed air. 

Amount of spent 

media

Following blasting of 9 coupons, approximately 40 L of dispensed water was 

collected in the collection drum. Over the course of the evaluation, an estimated 4 L 

of water was not collected by the vacuum and ran down the test stand and sprayed 

onto the operator.

Secondary waste 

management

An estimated 90% of the water was collected by the vacuum. However, during 

testing there was a visible mist that extended approximately two feet surrounding the 

spray tool. As mentioned in the text, drops of water flowed down over the surface of 

the test stand during application of the 3WDS to coupons higher on the test stand. 

The mist that extended from the spray tool caused the outer layer of the operator’s 

protective equipment to become very wet. This was a concern from the standpoint of 

protecting the operator from radiological contamination. Small pools of water 

collected at the base of the test stand. These pools of water were collected using the 

vacuum as well as absorbent rags. The radiological control technicians that oversaw 

the evaluation determined that no measureable contamination occurred due to the 

3WDS water.

Surface damage Pressurized water and vacuum collection removed loose particles from surface of 

concrete coupon, but did not visibly damage the surface.

Cost The 3WDS costs $24,500 for the vacuum, pressure washer, and discharge pump 

situated on a portable stand with wheels. The hand cleaning tool with the rotating 

water jet would be an additional approximately $3,500 - $5,000.
15 

6.0 Performance Summary

This section presents Battelle’s findings 

from the evaluation of the 3WDS for each 

performance parameter evaluated. 

6.1 Decontamination Efficacy 

The decontamination efficacy (in terms of 

%R) attained by the 3WDS was evaluated 

for each concrete coupon used during the 

evaluation. When the decontamination 

efficacy metrics (DF and %R) of the eight 

contaminated coupons were averaged 

together, the average %R for the 3WDS

was 36% ± 4% and the average DF was 

1.58 ± 0.09. 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 

The rate at which the 3WDS could be 

used to decontaminate a vertical surface 

was approximately 5.4 m2

per hour. The 

3WDS caused no visible surface 

destruction of the coupons. 

Approximately 40 L of secondary liquid 

waste was generated during application. 

The texture of the concrete surface is not 

likely to be important to the efficacy of 

the 3WDS and similar water blasting 

radiological decontamination 

technologies. The high pressure water 

should access most concrete surfaces, 

regardless of the irregularities. The 3WDS

was used with a gas-powered, dieselheated high pressure hot water washer. In 

addition, the vacuum recovery system 

required an air compressor to provide at 

least 250 cfm of air flow at a pressure of 

120 psi. A large diesel powered air 

compressor was used during this 

evaluation to power the 3WDS vacuum. 

These pieces of equipment were the only 

two sources of power required and could 

limit the locations at which the 3WDS can 

be used. 

A very limited evaluation of crosscontamination was performed. During an 

actual decontamination of a vertical 

surface, the higher elevation surfaces 

would likely be decontaminated first, 

possibly exposing the lower elevation 

surface 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 3WDS in the 

same way as the other coupons. Following 

decontamination, the uncontaminated 

coupon exhibited a small but measurable 

activity (0.0019 μCi compared with 

approximately 0.7 μCi on the coupons 

that had been decontaminated), suggesting 

that minimal cross contamination had 

occurred in the process of 

decontaminating the other coupons and 

this coupon using the 3WDS. In addition, 

the 3WDS created a significant amount of 

mist around the spray tool. This mist 

caused the operator’s outer layer of 

protective gear to become very wet. The 

possibility of contaminating the operators 

with secondary waste would likely be a 

safety concern in an actual 

decontamination operation. 
16 

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). 
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