EPA 600/R-13/002 | February 2013 | www.epa.gov/ord
United States
Environmental Protection
Agency
Technology Evaluation Report
Decontamination of Concrete
and Granite Contaminated
with Cobalt-60 and
Strontium-85
Office of Research and Development
National Homeland Security Research Center
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EPA/600/R-13/002
February 2013
Technology Evaluation Report
Decontamination of Concrete and
Granite Contaminated with Cobalt-60
and Strontium-85
National Homeland Security Research Center
Office of Research and Development
U.S. Environmental Protection Agency
26 Martin Luther King Drive
Cincinnati, OH 45268
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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 Contract No. EP-C-10-001 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, j ohn@ epa. gov
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FOREWORD
The U.S. 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.
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
in
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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, Office of Research and Development (ORD)/NHSRC
Emily Snyder, ORD/NHSRC
Scott Faller, Office of Air and Radiation (OAR)/Office of Radiation and Indoor Air (ORIA)
Jennifer Mosser, OAR/ORIA
Terry Stilman, Region 4
Battelle Memorial Institute
United States Department of Energy's Idaho National Laboratories
Portage, Inc.
IV
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Contents
Disclaimer ii
Foreword iii
Acknowledgments iv
Contents v
Abbreviations/Acronyms vii
Executive Summary viii
1.0 Introduction 1
2.0 Technology Description 3
2.1 Environmental Alternatives, Inc. Rad-Release II 3
2.2 Argonne SuperGel 4
3.0 Experimental Details 5
3.1 Experimental Preparation 5
3.2 Decontamination Technology Procedures 8
3.3 Decontamination Conditions 10
4.0 Quality Assurance/Quality Control 11
4.1 Intrinsic Germanium Detector 11
4.2 Audits 12
4.3 QA/QC Reporting 13
5.0 Evaluation Results and Performance Summary 14
5.1 Decontamination Efficacy 14
5.2 Deployment and Operational Factors 17
6.0 References 20
v
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Tables
Table 3-1. Concrete Characterization 5
Table 3-2. Number of Coupons included in Technology Evaluation 6
Table 3-3. Details of Each Testing Time Period 10
Table 4-1. Calibration Results - Difference (keV) from Th-228 Calibration Energies 11
Table 4-2. NIST-Traceable Eu-152 Activity Standard Check 12
Table 5-1. RRII Co-60 Decontamination Efficacy Results 15
Table 5-2. RRII Sr-85 Decontamination Efficacy Results 15
Table 5-3. ASG Co-60 Decontamination Efficacy Results 16
Table 5-4. ASG Sr-85 Decontamination Efficacy Results 16
Table 5-5. Operational Factors of RRII 18
Table 5-6. Operational Factors of ASG 19
Figures
Figure 3-1. Surface finish of concrete and granite coupons 6
Figure 3-2. Demonstration of contaminant application technique 7
Figure 3 -3. Containment tent (outer view) and inner view with test stand containing
contaminated coupons 8
Figure 3-4. Rinsing and vacuuming RRII from concrete coupon 9
Figure 3 -5. ASG before application, as applied to coupon, and during vacuum removal 9
VI
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Abbreviations/Acronyms
ANSI
ASG
Bq
°C
cm
Co
DARPA
DF
DHS
EAI
EPA
Eu
g
IEEE
INL
keV
mL
L
m
m2
nCi
NHSRC
NIST
%R
PE
PPE
QA
QAPP
QC
QMP
RDD
RML
RRII
RSD
Sr
TTEP
Th
American National Standards Institute
Argonne SuperGel
Bequerel
degrees Celsius
centimeters
cobalt
Defense Advanced Research Projects Agency
decontamination factor
U.S. Department of Homeland Security
Environmental Alternatives, Inc.
U. S. Environmental Protection Agency
europium
gram
Institute of Electrical and Electronics Engineers
Idaho National Laboratory
kilo electron volts
milliliter
liter
meter
square meters
microCuries
nanoCuries
National Homeland Security Research Center
National Institute of Standards and Technology
percent removal
performance evaluation
personal protective equipment
quality assurance
quality assurance project plan
quality control
quality management plan
radiological dispersion device
Radiological Measurement Laboratory
Rad-Release II
relative standard deviation
strontium
Technology Testing and Evaluation Program
thorium
vn
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Executive Summary
The U.S. Environmental Protection Agency's (EPA's) 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 recently evaluated the performance of Environmental
Alternatives, Inc.'sRad-Release II (RRII), and ArgonneNational Laboratory's SuperGel
(ASG) intended specifically for decontamination of radiological contamination. The
objective of evaluating these technologies was to test their ability to remove radioactive
cobalt (Co)-60 and strontium (Sr)-85 from the surface of unpainted concrete and split
face granite.
RRII was applied as a liquid with spray bottles and removed with a water rinse and
vacuum. ASG was applied as a gel and removed with a vacuum. Prior to the application
of each decontamination technology, 15 centimeter (cm) x 15 cm unpainted concrete and
split face granite coupons were contaminated with liquid aerosols of Co-60 and Sr-85 and
placed in a vertical test stand. Following manufacturer's recommendations, the
decontamination technologies were applied to all the coupons on the test stand.
Thereafter, the residual activity on the contaminated coupons was measured. Important
deployment and operational factors were also documented and reported.
A summary of the evaluation results for RRII and ASG is presented below while a
discussion of the observed performance can be found in Section 5 of this report.
Decontamination Efficacy: The decontamination efficacy (in terms of percent removal,
%R) attained by RRII and ASG was evaluated following contamination of the coupons
with approximately one microCurie (|iCi) Co-60 and Sr-85, measured by gamma
spectroscopy. For the concrete coupons, the %Rs for Co-60 were determined to be 79%
± 6.0% for RRII and 62% ± 5.2% for ASG and for Sr-85, 70% ± 6.1% for RRII and 40%
±7.1% for ASG. For the granite coupons, the %Rs for Co-60 were determined to be
64% ± 10% for RRII and 48% ± 14% for ASG and for Sr-85, 44% ± 4.4% for RRII, 32%
± 2.2% for ASG. Therefore, across all the decontamination technologies, on average, the
Co-60 was more effectively decontaminated than the Sr-85 and the concrete was more
effectively decontaminated than the granite.
Deployment and Operational Factors: Use of RRII included a two-step spray
application to each surface material coupon and rinse and removal that involved two 30
minute waiting periods. ASG was a one step application that included vacuum removal
after a 90 minute wait period. Both decontamination technologies seem well suited for
rough or jagged surfaces as the spray and gel can reach most areas easily, however, the
vacuum removal step could become difficult on rough surfaces. Neither the surface
finish of the concrete or the granite coupons were visibly affected by either of the
decontamination technologies.
vin
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1.0 Introduction
The U.S. Environmental Protection Agency's (EPA's) National Homeland Security Research
Center (NHSRC) is helping to protect human health and the environment from adverse effects
resulting from intentional acts of terror. With an emphasis on decontamination and consequence
management, water infrastructure protection, and threat and consequence assessment, NHRSC is
working to develop tools and information that will help detect the intentional introduction of
chemical or biological contaminants in buildings or water systems, the containment of these
contaminants, the decontamination of buildings and/or water systems, and the disposal of
material resulting from clean-ups.
NHSRC, through its Technology Testing and Evaluation Program (TTEP), works in partnership
with recognized testing organizations; with stakeholder groups consisting of buyers, vendor
organizations, and permitters; and with the participation of individual technology developers in
carrying out performance tests on homeland security technologies. The program evaluates the
performance of innovative 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 results are defensible. NHSRC, through TTEP (for example), provides high-quality
information that is useful to decision makers in purchasing or applying the evaluated
technologies. Potential users are provided 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.
Through TTEP, NHSRC evaluated the decontamination efficacy (results in this report) of two
separate technologies: 1) Environmental Alternatives, Inc.' s Rad-Release II (RRII), and 2)
Argonne National Laboratory's SuperGel (ASG) in decontamination of radioactive cobalt-60
(Co-60) and strontium-85 (Sr-85) from unpainted concrete and granite. This evaluation was
conducted according to a quality assurance project plan (QAPP) entitled, "Evaluation of
Chemical Technologies for Decontamination of Cobalt, Strontium, and Americium from Porous
Surfaces", Version 1.0 dated May 8, 2012 (available upon request) that was developed according
to the requirements of the TTEP Quality Management Plan (QMP) Version 3, January 2008.
The following performance characteristics of RRII and ASG were evaluated:
• Decontamination efficacy was defined as the extent of radionuclide removal following
application of the decontamination technology to concrete and granite coupons to which
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Co-60 and Sr-85 had been applied. Another quantitative parameter evaluated was the
extent of cross contamination onto uncontaminated surfaces due to the decontamination
procedure.
• Deployment and operational data including rate of surface area decontamination,
applicability to irregular surfaces, skilled labor requirement, utilities requirements, extent
of portability, shelf life of media, secondary waste management including the estimated
amount and characteristics of the spent media, and the cost of using the technologies.
This technology evaluation took place during July 2012 at the U. S. Department of Energy's
Idaho National Laboratory (INL).
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2.0 Technology Description
This report provides results for the evaluation of RRII and ASG. Following is a description of
each technology, based on information provided by the vendor. The information provided below
was not verified during this evaluation.
2.1 Environmental Alternatives, Inc. Rad-Release II
The RRII decontamination technology is a chemical process that involves the sequential topical
application of two solutions (applied in the order directed by EAI). RRII extracts radionuclides,
including transuranics, from nearly all substrates. This process was developed to be used in
sequence to synergistically remove the contaminants via the migration pathways, pores and
capillaries of the contaminated material.
To maximize the efficacy of the extraction process, the chemistry and application are tailored to
the specific substrate, targeted contaminant(s), and surface interferences. RRII Formula 1
contains salts to promote ion exchange and surfactants to remove dirt, oil, grease, and other
surface interferences. Broad-target and target-specific chelating agents are blended into the
solution to sequester and encapsulate the contaminants, keeping them in suspension until they are
removed by the subsequent rinse. RRII Formula 2 is designed as a caustic solution containing
salts to promote ion exchange, ionic and nonionic surfactants, and additional sequestering agents,
also utilized to encapsulate the contaminants and keep them in suspension until they are removed
by the subsequent rinse.
RRII is applied in low volumes, as either an atomized spray or foam (active ingredients do not
change). According to the manufacturer, foam deployment of the solution is most appropriate
for large scale applications while the spray application (as used during this evaluation) is
beneficial for smaller applications and applications where waste minimization is a critical factor.
Several options are available to facilitate the removal step including vacuuming, simple wiping
with absorbent laboratory wipes or rags for small surfaces, use of a clay overlay technique to
wick out RRII and contamination over time and then removing the clay at a later date, or use of
an absorbent polymer that is sprayed over the chemically treated surface to leach or wick out the
contaminant laden solutions and bind them. The sequence of application, dwell, rinse, and
removal of the decontamination solution constitutes a single iteration. This procedure may be
repeated, as needed, until the desired residual contaminant levels are achieved. More
information is available at www.eai-inc.com.
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2.2 Argonne SuperGel
The ASG is a system of super-absorbing polymers containing solid sequestering agents dissolved
in a nonhazardous ionic wash solution. The resulting hydrogel is applied to a contaminated
surface and provides exchangeable ions to the substrate to promote the desorption of
radionuclides. The solid sequestering agent provides strong sorption of the target radionuclides
within the gel. After removing the radionuclide-laden hydrogel by conventional wet vacuum, the
contaminated hydrogel can be dehydrated or incinerated to minimize waste volume without loss
of volatilized contaminants. To summarize, ASG provides for:
• in situ dissolution of bound contaminants without dissolving or corroding contaminated
structural components;
Controlled extraction of water and dissolved radionuclides from the surface and
pore/microcrack structures into a super-absorbing hydrogel;
Rapid stabilization of the solubilized radionuclides with high-affinity and high-specificity
sequestering agents immobilized in the hydrogel layer; and
• Low toxicity reagents and low volume radioactive waste.
The superabsorbing polymers consist of an anionic mixture of polyacrylamide and polyacrylate
in both linear and cross-linked form. The solid sequestering agents are mixed into the dry
polymer (10% by mass). The ionic wash solution is composed of a single component salt at 1
mole/liter (L) concentration (no strong acid or base is used). The reconstituted hydrogel (19-20
gram ionic wash solution per gram of dry polymer mix) can be applied by hand for small areas or
sprayed on for larger applications. The hydrogel is allowed to react with the contaminated
surface for at least 60-90 minutes to maximize the ionic exchange of radionuclides and
diffusion/absorption into the hydrogel. The hydrogel is designed to adhere to vertical surfaces
without slipping and maintain hydration in direct sunlight for more than an hour. Because no
component of the hydrogel is hazardous, there are no special precautions required to deal with
hazardous materials.
Conventional wet-vacuum technology is sufficient to remove the hydrogel from the
contaminated surface. For small-scale applications, the head of a standard wet vacuum is
adequate, while for larger scale applications, a squeegee attachment is recommended.
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3.0 Experimental Details
3.1 Experimental Preparation
3.1.1 Concrete Coupons
Concrete coupons were prepared in a single batch of concrete made from Type II Portland
cement. The ready-mix company (Burns Brothers Redi-Mix, Idaho Falls, ID) from which the
concrete for this evaluation was obtained provided the data shown in Table 3-1 describing the
cement clinker used in the concrete mix. The ASTM Cl 501 requirement for Type II Portland
cement is that the tri calcium aluminate content be less than 8% of the overall cement clinker. As
shown in Table 3-1 the cement clinker used for the concrete coupons was 4.5% tri calcium
aluminate. Because the only difference between Type I and II Portland cements is the maximum
allowable tricalcium aluminate content, and the maximum for Type I is 15%, the cement used
during this evaluation meets the specifications for both Type I and II Portland cements.
Table 3-1. Concrete Characterization
Cement Constituent Percent of Mixture
Tricalcium Silicate 57.6
Dicalcium Silicate 21.1
Tricalcium Aluminate 4.5
Tetracalcium 8.7
Aluminoferrite
Minor Constituents 8_1
To make the concrete coupons, the wet concrete was poured into 0.9 meter (m) square plywood
forms (approximately 4 centimeters [cm] deep) with the surface exposed. The surface was then
"floated" to get the smaller aggregate and cement paste to float to the top (the surface used for
this evaluation), and then cured for 21 days. Following curing, the 4 cm thick squares were cut
with a laser guided rock saw to the desired concrete coupon size of approximately 15 cm x 15
cm. The coupons had a surface finish that was consistent across all the coupons. In addition, the
concrete was representative of exterior concrete commonly found in urban environments in the
United States as shown by INL under a U.S. Department of Defense, Defense Advanced
Research Projects Agency (DARPA) and U.S. Department of Homeland Security (DHS)
project2.
The granite coupons were provided by INL and were approximately 16 cm x 16 cm and 4 cm
thick. These coupons consisted of a Milford Pink Granite (Fletcher Granite Co., Westford,
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Massachusetts) that is pinkish gray with areas of black and white. The surface finish of the
granite coupons was a split face granite, a rugged, uneven finish produced by splitting granite
with shims, wedges, or hydraulics. This type of granite has been used in the U.S. National
Archives Building, the Smithsonian, and the United States Department of the Interior Building in
Washington, DC. Figure 3-1 shows the surface finish of both the concrete and granite coupons.
Figure 3-1. Surface finish of concrete and granite coupons.
3.1.2 Coupon Contamination
Table 3-2 describes the number of coupons used in this technology evaluation. Regardless of
surface type, all of these coupons were contaminated with 2.5 milliliters (mL) of unbuffered,
slightly acidic aqueous solution containing approximately 0.4 microCurie (|iCi)/mL Co-60 or Sr-
85 which corresponds to an activity level of approximately 1 jiCi per coupon (± 0.5 jiCi). In the
case of an actual urban radiological dispersion device (RDD) event, dry contaminated particles
are expected to settle over a wide area of a city. Application of the radionuclides in an aqueous
solution was justified because even if Co-60 and Sr-85 were to be dispersed in a dry particle
form following an RDD event, morning dew or rainfall would likely occur before the surfaces
could be decontaminated. In addition, from an experimental standpoint, the ability to apply
liquids homogeneously across the surface of the concrete coupons greatly exceeds that capability
for dry particles. The aqueous contamination was delivered to each coupon using an
aerosolization technique developed by INL under the DARPA/DHS project2. Coupons were
contaminated approximately two weeks before use.
Table 3-2. Number of Coupons included in Technology Evaluation
Coupons
Surface Material
Concrete
Granite
Decon by
RRII
4
4
Decon by
ASG
4
4
Cross-
contamination
Blanks
2
-
Laboratory
Blanks
5
5
The aerosol delivery device was constructed of two syringes. The plunger and needle were
removed from the first syringe and discarded. A compressed air line was then attached to the
rear of this syringe. The second syringe containing 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 liter (L) per minute created a
turbulent flow through the first syringe. When the contaminant solution in the second syringe
was introduced, the contaminant 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
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fine liquid droplets onto the coupon surface. The contaminant spray was applied all the way to
the edges of the coupon, which were masked with tape (after having previously been sealed with
polyester resin) to ensure that the contaminant was applied only to the working surfaces of the
coupons. The photographs in Figure 3-2 show this procedure being performed using a
nonradioactive, nonhazardous aqueous dye to demonstrate that 2.5 mL of contaminant solution is
effectively distributed across the surface of the coupon.
Figure 3-2. Demonstration of contaminant application technique.
3.1.3 Measurement of Activity on Coupon Surface
Gamma radiation from the surface of each contaminated coupon was measured to quantify
contamination levels both before and after application of the two decontamination technologies
using an intrinsic high purity germanium detector (Canberra LEGe Model GL 2825R/S,
Meriden, CT). After each coupon was placed in front of the detector face, gamma ray spectra
were collected until the average activity level of Co-60 and Sr-85 from the surface stabilized to a
relative standard deviation (RSD) of less than 2%. Gamma-ray spectra acquired from
contaminated coupons were analyzed using INL Radiological Measurement Laboratory (RML)
data acquisition and spectral analysis programs. Radionuclide activities on each of the 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. The minimum detectable level of each radionuclide was 0.3
nanoCuries (nCi) for Co-60 and 0.2 nCi for Sr-85 on these coupons.
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Figure 3-3. Containment tent (outer view) and inner view with test stand containing
contaminated coupons.
3.1.4 Surface Construction Using Test Stand
To evaluate the decontamination technologies on vertical surfaces (simulating walls), a stainless
steel test stand (2.7 m x 2.7 m) designed to hold three rows of coupons was used. The granite
coupons were slightly too big to fit into the openings in the test stand so a second smaller test
stand was used only for the granite coupons. As shown in Figure 3-3, both test stands were
located in 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 and the granite
coupons were placed in a row next to one another on the smaller test stand. Nine coupons (four
concrete, four granite, and one concrete blank) were decontaminated together. The four concrete
coupons placed in the top two rows of the middle and left of the large test stand (see Figure 3-3)
were contaminated and the one concrete coupon in the bottom row was an uncontaminated blank
concrete coupon. This blank coupon was placed there to observe the extent of cross
contamination caused by the decontamination higher on the wall or transfer of contaminants due
to use of decontamination equipment higher on the wall.
3.2 Decontamination Technology Procedures
3.2.1 EAIRRII
The application of RRII onto the nine coupons was performed using plastic spray bottles (32 oz.
Heavy Duty Spray Bottle, Rubbermaid Professional, Atlanta, GA) according to the
manufacturer's recommended procedures. The coupons were thoroughly wetted with RRII
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Figure 3-4. Rinsing and vacuuming
RRII from concrete coupon
Formula 1 with 3-4 sprays. The solution was
then worked into the surface of the coupon by
scrubbing the entire surface of the coupon once
with a scouring pad (Heavy Duty Scouring Pad,
3M Scotch-Brite, St. Paul, MN). During this
evaluation, the initial application of RRII Formula
1 took only 10-15 seconds for each coupon. The
next step was a 30 minute dwell time for RRII
Formula 1 to reside on the surfaces of the coupons.
The coupon surfaces were kept damp with 1 -2
sprays of additional RRII Formula 1 approximately
every five minutes. The additional 1-2 sprays of
RRII Formula 1 were performed to simulate foam
collapse, i.e., the reintroduction of fresh solutions
to the contaminated matrix, as would be observed when RRII was deployed as a foam for larger
scale real-world applications. After the 30 minute dwell time, the coupon surfaces were
thoroughly wetted with a 10% nitric acid rinse solution (in deionized water) using another spray
bottle. The surface was then vacuumed a final time (12 gallon, 4.5 horsepower, QSP® Quiet
Deluxe, Shop-Vac Corporation, Williamsport, VA) which took about 25 seconds per coupon.
The above procedure was then repeated for RRII Formula 2. Altogether, the RRII procedure took
68 and 73 minutes to complete for the two sets of nine coupons. Figure 3-4 shows the rinse and
vacuuming step of the RRII procedure.
3.2.2 ASG
The ASG was prepared by mixing two dry powders with water according to the manufacturer's
recommended procedures. The mixture was then stirred with a drill equipped with a mixing tool
until the mixture was homogeneous. The ASG was applied to the nine coupons using a four-inch
paint brush to smooth the ASG across the surface. The specifications of the paint
brush/spackling knife were not critical as a perfectly smooth application was not required.
Altogether, the application of the ASG required approximately 20 seconds per coupon, ASG was
allowed to stay on the surface for 90 minutes, and then was removed with a wet vacuum (12
gallon, 4.5 horsepower, QSP® Quiet Deluxe, Shop-Vac Corporation, Williamsport, VA) which
required approximately 20 seconds per coupon. Figure 3-5 shows the application and vacuum
removal steps for ASG.
Figure 3-5. ASG before application, as applied to coupon, and during vacuum
removal.
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3.3 Decontamination Conditions
The decontamination technology testing was performed over the course of three days. Table 3-3
presents the number of days between coupon contamination and decontamination, the
temperature (or range) in degrees Celsius (°C) and the percent relative humidity measured during
the evaluation.
Table 3-3. Details of Each Testing Time Period
Time Between Temperature
Coupon During Relative Humidity
Contamination and Decontamination During
Technology Decontamination (°C) Decontamination (%)
Co-60 13 days 25.6 40
Sr-85 13 days 21.7 36
10
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4.0 Quality Assurance/Quality Control
QA/QC procedures were performed in accordance with the QMP and the test/QA plan for this
evaluation.
4.1 Intrinsic Germanium Detector
The germanium detector was calibrated weekly during the evaluation. 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). Table 4-1 presents the calibration results
across the duration of the project. In each row are shown the difference between the known
energy levels and those measured following calibration (rolling average across the six most
recent calibrations). Each row represents a six week rolling average of calibration results. These
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 (keV) from Th-228 Calibration Energies
Measurement
Month
July 2012
August 20 12
Calibration Energy Levels in keV
Date Range
7-3-12 to 7-24-12
7-9-12 to 8-14-12
Energy 1
238.632
-0.002
-0.004
Energy 2 Energy 3
583.191 860.564
0.007 -0.028
0.012 -0.034
Energy 4
1620.735
-0.110
-0.159
Energy 5
2614.511
0.011
0.016
Gamma ray counting was continued for each coupon until the activity level of Co-60 and Sr-85
on the surface had a RSD of less than 2%. This RSD was achieved during the first 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 the data analyst independently arrived at the same value the
data were considered certified. This process defined the full gamma counting QA process for
certified results.
11
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The background activity of laboratory blank coupons was determined by analyzing five
arbitrarily selected coupons from the stock of concrete and granite coupons used for this
evaluation. The ambient activity level of these coupons was measured for one hour. No activity
was detected above the minimum detectable level of 0.3 nCi for Co-60 and 0.2 nCi for Sr-85 on
these coupons.
Throughout the evaluation, a second measurement was taken on four coupons in order to provide
duplicate measurements to evaluate the repeatability of the instrument. Two of the duplicate
measurements were performed after contamination but prior to application of the
decontamination technologies and two were performed after decontamination. All four of the
duplicate pairs showed percent difference in activity level of 4% or less, below the acceptable
percent difference of 5%.
4.2 Audits
4.2.1 Performance Evaluation A udit
RML performs monthly checks of the accuracy of the Th-228 daughter calibration standards by
measuring the activity of a National Institute of Standards and Technology (NIST)-traceable
europium (Eu)-152 standard (in units of Bequerel, Bq) and comparing the results 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 served 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 these audits of the detector that was used
during this evaluation. All results were within the acceptable difference of 7%.
Table 4-2. NIST-Traceable Eu-152 Activity Standard Check
Date
TnK? 9D1 9
July /ui/
AUgUSt Z(J iZ
Eu-152
(keV)
Average
122
779
1408
Average
122
779
1408
NIST Activity
(Bq)
124,600
124,600
124,600
124,600
124,600
124,600
124,600
124,600
INL RML
Result (Bq)
122,000
118,900
121,000
120,600
122,300
118,600
121,300
122,600
Difference
2.1%
4.6%
2.9%
3.2%
1.8%
4.8%
2.6%
1.6%
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4.2.2 Data Quality Audit
At least 10% of the data acquired during the evaluation were audited. The QA Manager traced
the data from the initial acquisition, through reduction and statistical analysis, to final reporting,
to ensure the integrity of the reported results. All calculations performed on the audited data
undergoing. No significant findings were noted.
4.3 QA/QC Reporting
Each assessment and audit was documented in accordance with the Q APP and the QMP.
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5.0 Evaluation Results and Performance Summary
5.1 Decontamination Efficacy
The decontamination efficacy was determined for each contaminated coupon in terms of percent
removal (%R) and decontamination factor (DF) as defined by the following equations:
%R = (1 -Af/Ao) x 1 00% and DF =
where AO is the radiological activity from the surface of the coupon before application of the
decontamination technologies and Af is radiological activity from the surface of the coupon after
removal. While the DFs are reported in the following data tables, the narrative describing the
results will focus on the %R.
5.1.1 RRII Results
Table 5-1 presents the decontamination efficacy, expressed as both %R and DF for RRII when
decontaminating Co-60 from concrete and granite surface coupons and
Table 5-2 presents the same data for Sr-85 decontamination. The target activity for each of the
contaminated coupons (pre-decontamination) was between 0.5 jiCi and 1.5 jiCi. The overall
(both RRII and ASG included) average activity (plus or minus one standard deviation) of the Co-
60 contaminated coupons was 0.83 jiCi ± 0.05 jiCi, a variability of 6% and for Sr-85, 1.06 jiCi ±
0.08 |iCi, a variability of 8%.
The decontamination efficacies of RRII in terms of %R for Co-60 were 79% ± 6% for the
concrete surfaces and 64% ± 10% for the granite surfaces. For Sr-85, the %Rs were 70% ± 6%
for the concrete surfaces and 44% ± 4% for the granite surfaces. Several t-tests were performed
to determine the likelihood that results for each contaminant and surface were the same. The %R
of Co-60 decontaminated by RRII from concrete was not significantly different than the %R of
Co-60 decontaminated by RRII from granite at the 95% confidence interval (p=0.15). However,
the %R of Sr-85 decontaminated by RRII from concrete was significantly different (higher) than
the %R of Sr-85 decontaminated by RRII from granite (p=0.02). The %Rs of Co-60 and Sr-85
decontaminated by RRII from concrete were not significantly different from one another
(p=0.22) while the %R of Co-60 decontaminated by RRII from granite was significantly
different (higher) than was the %R of Sr-85 decontaminated by RRII from granite (p=0.03).
As described above in Section 3.1.4, cross contamination blanks were included in the test stand
during testing with both contaminants to evaluate the potential for cross contamination due to
application of RRII on wall locations above the blank. In both cases the cross contamination
14
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Table 5-1. RRII Co-60 Decontamination Efficacy Results
Surface Material
Concrete
Granite
Pre-Decon Activity
(uCi/Coupon)
0.86
0.89
0.83
0.86
Avg 0.86
SD 0.02
0.84
0.73
0.86
0.88
Avg 0.83
SD 0.07
Post-Decon Activity
(uCi/Coupon)
0.20
0.11
0.18
0.23
0.18
0.05
0.33
0.35
0.27
0.22
0.29
0.06
%R
77%
88%
78%
74%
79%
6%
61%
52%
69%
75%
64%
10%
DF
4.4
8.2
4.5
3.8
5.2
2.0
2.5
2.1
3.2
4.0
3.0
0.8
Table 5-2. RRII Sr-85 Decontamination Efficacy Results
Surface Material
Concrete
Granite
Pre-Decon Activity
(uCi/Coupon)
1.13
1.12
1.12
1.15
Avg 1.13
SD 0.01
0.91
0.97
0.96
1.00
Avg 0.96
SD 0.04
Post-Decon Activity
(uCi/Coupon)
0.38
0.40
0.30
0.26
0.34
0.07
0.57
0.52
0.54
0.53
0.54
0.02
%R
66%
64%
73%
77%
70%
6%
37%
46%
44%
47%
44%
4%
DF
3.0
2.8
3.7
4.4
3.5
0.8
1.6
1.9
1.8
1.9
1.8
0.1
blanks were concrete coupons that had not been contaminated and the pre-decontamination
activity measurements indicated extremely low background levels (below the detection limit) of
activity. These coupons were decontaminated using RRII along with the other contaminated
coupons and the post-decontamination measurements of the activity of these blanks were found
to be 0.048 jiCi for Co-60 and 0.011 for Sr-85. This increased level of activity was less than 6%
and 2% for Co-60 and Sr-85, respectively, of the activity applied to each of the contaminated
coupons. Therefore, the cross contamination was minimal but still detectable, and enough to
note that the possibility exists that cross contamination to locations previously not contaminated
is a possibility when using RRII in a wide area application.
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5.1.2 ASG Results
Table 5-3 present the decontamination efficacy, expressed as both %R and DF for ASG when
decontaminating Co-60 from concrete and granite surface coupons and Table 5-4 presents the
same data for Sr-85 decontamination. As with the previous technology, the overall average
activity (plus or minus one standard deviation) of the Co-60 contaminated concrete coupons was
0.83 |iCi ± 0.05 |iCi, a variability of 6% and for Sr-85, 1.06 |iCi ± 0.08 |iCi, a variability of 8%.
Table 5-3. ASG Co-60 Decontamination Efficacy Results
Surface Material
Concrete
Avg
SD
Granite
Avg
SD
Pre-Decon Activity
(uOCoupon)
0.76
0.87
0.86
0.89
0.85
0.06
0.81
0.79
0.78
0.80
0.80
0.01
Table 5-4. ASG Sr-85 Decontamination Efficacy
Surface Material
Concrete
Avg
SD
Granite
Avg
SD
Pre-Decon Activity
(uOCoupon)
1.18
1.04
1.11
1.14
1.12
0.06
1.04
1.08
0.96
1.03
1.03
0.05
Post-Decon Activity
(uOCoupon)
0.31
0.263
0.33
0.37
0.32
0.04
0.46
0.254
0.43
0.52
0.42
0.11
Results
Post-Decon Activity
(uOCoupon)
0.81
0.65
0.58
0.65
0.67
0.10
0.72
0.72
0.68
0.68
0.70
0.02
%R
59%
70%
62%
58%
62%
5%
43%
68%
45%
35%
48%
14%
%R
31%
38%
48%
43%
40%
7.1%
31%
33%
29%
34%
32%
2.2%
DF
2.5
3.3
2.6
2.4
2.7
0.4
1.8
3.1
1.8
1.5
2.1
0.7
DF
1.5
1.6
1.9
1.8
1.68
0.20
1.4
1.5
1.4
1.5
1.47
0.05
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The decontamination efficacies of RRII in terms of %R for Co-60 were 62% ± 5.2% for
decontamination of the concrete surfaces with ASG and 48% ± 14% for decontamination of the
granite surfaces with ASG. For Sr-85, the %Rs were 40% ± 7% for decontamination of the
concrete surfaces with ASG and 32% ± 2% for decontamination of the granite surfaces with
ASG. As for RRII, several t-tests were performed to determine the likelihood that results for
each contaminant and surface were the same. The %R of Co-60 by ASG from concrete was
significantly different (higher) from the %R from granite at the 95% confidence interval
(p=0.048), but the %R of Sr-85 by ASG from concrete was not significantly different from the
%R from granite (p=0.13). The %Rs of Co-60 from concrete were significantly different from
the %R of Sr-85 from concrete (p=0.015) while the %R of Co-60 and Sr-85 from granite were
not significantly different from one another (p=0.11).
As for the RRII testing, the cross contamination blanks were included in the test stand during
testing with both contaminants to evaluate the potential for cross contamination due to
application of ASG on wall locations above the blank. The cross contamination blanks were
concrete coupons that had not been contaminated and the pre-decontamination activity
measurements indicated extremely low background levels (below the detection limit) of activity.
These coupons were decontaminated using ASG along with the other contaminated coupons.
The post-decontamination measurement of activity of these blanks were found to be 0.56 nCi for
the Co-60 and 1.2 nCi for the Sr-85. This increased level of activity was approximately 0.1% of
the activity added to each of the contaminated coupons for Co-60 and Sr-85. Therefore, the
cross contamination was very minimal during application of ASG.
5.2 Deployment and Operational Factors
Throughout the evaluation, technicians were required to use full anti-contamination personal
protective equipment (PPE) because the work was performed in a radiological enclosure using
Co-60 and Sr-85 on the coupon surfaces. Whenever radiological material was handled, anti-
contamination PPE was required and any waste (e.g., from removal of the decontamination
technology foams and reagents) was considered at a minimum as low level radioactive waste
(and was disposed of accordingly). The requirement for this level of PPE was not driven by the
use of the decontamination technologies (which are not hazardous), but rather the presence of
Co-60 and Sr-85.
5.2.1 RRII
A number of operational factors were documented by the technician who performed the testing
with RRII. The application process of RRII was described in Section 3.2.1 and included use of a
plastic spray bottle. Application of RRII solutions to each coupon took 10-15 seconds in
addition to the recommended dwell time of 30 minutes for each solution. For RRII, there were
two formulas that were applied using the identical procedure which included a 30 minute dwell
time for each. The total elapsed time for the nine coupons decontaminated with RRII was
approximately 68 and 73 minutes for Co-60 and Sr-85, respectively. These application and
removal times are applicable only to the experimental scenario using small concrete coupons.
According to the manufacturer, if RRII were to be applied to larger surfaces, larger application
tools such as larger sprayers or foamers would likely be used which would impact the application
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rate. In addition, larger vacuum heads would be used for removal. RRII did not cause any
visible damage to the surface of the coupons. The RRII coupons did not dry completely
overnight. Table 5-5 provides some additional detail about the operational factors for RRII as
observed during the use of this experimental setup/test stand with relatively small concrete
coupons.
Table 5-5. Operational Factors of RRII
Parameter
Decontamination
rate
Applicability to
irregular surfaces
Skilled labor
requirement
Utilities
requirement
Extent of portability
Secondary waste
management
Surface damage
Cost
Description/Information
Technology Preparation: RRII is provided ready to use. The solutions (Formula 1
and Formula 2) were transferred into spray bottles and applied.
Application: Using this experimental setup, the initial application of RRII Formula 1
to the coupons took only seconds and then the coupons were kept damp (to simulate
the ongoing presence of a foam during a large-scale application) with reapplication
every 10 minutes during the dwell time. Following the 30 minute dwell time, rinsing
and vacuuming took approximately 25 seconds per coupon. This process was
repeated for RRII Formula 2. hi all, the application and removal steps took 8-13
minutes in addition to the two 30 minutes dwell times for RRII. Aside from the dwell
times, this corresponds to a decontamination rate of approximately 1 m2/hr for RRII.
Estimated volumes used per application of nine coupons (0.2 m2) included 280 mL
RRII Formula 1, 280 mL RRII Formula 2, and 200 mL of the rinse solution.
Application to irregular surfaces would not seem to be problematic, RRII is easily
sprayed into hard to reach locations. Irregular surfaces may pose a problem for
vacuum removal.
Adequate training would likely include a few minutes of orientation so the technician
is familiar with the application technique including dwell times and requirement of
keeping the surface wet. Larger surfaces may require more complex equipment such
as spray or foam application.
Electricity for the wet vacuum. Larger surfaces may require more complex equipment
such as spray or foam application requiring additional utilities.
At a scale similar to that used for this evaluation, vacuum removal would be the only
portability factor. However, for larger scale applications, limiting factors would
include the ability to apply RRn at a scale applicable to an urban contamination (area
of city blocks or square miles) and then rinse and remove with a vacuum Portable
electrical generation or vacuum capability may be required.
Approximately 760 mL of liquid was applied per nine coupons used during this
evaluation. That volume corresponds to a waste generation rate of approximately 4
L/m2 depending on how much of the solutions absorb to the surfaces.
Concrete and granite surfaces appeared undamaged.
RRII solutions are not sold as a stand-alone product but are only available as a
decontamination service for which the cost varies greatly from project to project.
Typical project costs are in the approximate range of $33-$55/m2.
5.2.2 ASG
A number of operational factors were documented by the technician who performed the testing
with ASG. Once fully mixed, ASG had the look of cooked oatmeal but was very slippery. A
paint brush was used to apply the ASG onto the concrete coupons. However, once on the
concrete, ASG adhered rather well. Altogether, the application of ASG took approximately 20
seconds per coupon and removal with a wet vacuum took approximately 20 seconds per coupon.
18
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ASG caused no visible damage to the surface of the coupons. Table 5-6 provides some
additional detail about the operational factors for ASG as observed during the use of this
experimental setup/test stand with relatively small concrete coupons.
Table 5-6. Operational Factors of ASG
Parameter
Decontamination
rate
Applicability to
irregular surfaces
Skilled labor
requirement
Utilities
requirement
Extent of portability
Secondary waste
management
Surface damage
Cost
Description/Information
Technology Preparation: 15 minutes to measure and mix powder with water.
ASG is able to be used for several days after mixing as long as ASG is kept
moist by covering the mixture as it will dry out if left exposed to air for several
days.
Application: ASG was applied with a paint brush to each coupon in
approximately 20 seconds (4 square meters (m2)/hour (hr)). After a 90 minute
dwell time, ASG was removed with a wet vacuum and the surface was wiped
with a paper towel at a rate of approximately 20 seconds per coupon (4 m2/hr).
Aside from the wait time (which is independent of the surface area), the
application and removal rate was approximately 2 m2/hr for application and
corresponding removal.
Estimated volumes used per nine coupons included 0.5-1 L of ASG. Overall
that volume corresponds to a loading of 2.5-5 L/m2.
Application to irregular surfaces may be problematic as ASG could slide off
jagged edges and be hard to apply to hard to reach locations. During use on
the rough split face granite, small amount of AS G could be seen remaining in
the crevices after vacuum removal.
Adequate training would likely include a few minutes of orientation so the
technician is familiar with the application technique. Larger surfaces may
require more complex equipment such as sprayer application.
As evaluated here, electricity was required to operate the wet vacuum
Electricity for the wet vacuum. Larger surfaces may require more complex
equipment such as spray application requiring additional utilities.
At a scale similar to that used for this evaluation, the only limitation on
portability would be the ability to provide vacuum removal in remote
locations. However, for larger scale applications, limiting factors would
include the ability to apply ASG at scale applicable to an urban contamination
(area of city blocks or square miles).
0.5-1 L of ASG was applied per nine coupons during this evaluation. That
volume corresponds to a waste generation rate of approximately 5-10 L/m2.
ASG was collected entirely by the wet vacuum
Concrete and granite surfaces appeared undamaged.
Cost of materials (labor not included) is approximately $0.30/L for ASG
(depending on source material costs). This cost corresponds to approximately
$2/m2 if used in a similar way as used during this evaluation.
19
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6.0 References
ASTM Standard C 150-07, 2007, "Standard Specification for Portland Cement," ASTM
International, West Conshohocken, PA, www.astm.org.
Radionuclide Detection and Decontamination Program, Broad Agency Announcement 03-
013, U.S. Department of Defense Defense Advanced Research Projects Agency (DARPA)
and the U.S. Department of Homeland Security, classified program.
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).
20
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United States
Environmental Protection
Agency
PRESORTED STANDARD
POSTAGE & FEES PAID
EPA
PERMIT NO. G-35
Office of Research and Development (8101R)
Washington, DC 20460
Official Business
Penalty for Private Use
$300
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