EPA 600/R-13/204 | September 2013 | www.epa.gov/ord
United States
Environmental Protection
Agency
Technology Evaluation Report
Decontamination of Concrete
and Granite Contaminated with
Americium-243
Office of Research and Development
National Homeland Security Research Center
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EPA 600-R-13-204
September 2013
Technology Evaluation Report
Decontamination of Concrete and
Granite Contaminated with
Americium-243
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
RESEARCH TRIANGLE PARK, NC 27711
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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.
The views expressed in this report are those of the authors and do not necessarily reflect the
views or policies of the Agency._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
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ACKNOWLEDGMENTS
Contributions of the following individuals and organizations to the development of this
document are gratefully acknowledged.
U.S. Environmental Protection Agency (EPA)
John Drake, Office of Research and Development (ORD)/NHSRC
Kathy Hall, ORD/NHSRC
Emily Snyder, ORD/NHSRC
James Mitchell, Region 5
Scott Hudson, Office of Emergency Management (OEM), Consequence Management Advisory
Team (CMAT)
Battelle Memorial Institute
U.S. Department of Energy's Idaho National Laboratories
in
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Contents
DISCLAIMER ii
ACKNOWLEDGMENTS iii
Contents ii
Abbreviations/Acronyms iv
Executive Summary vi
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 9
4.0 Quality Assurance/Quality Control 11
4.1 Intrinsic Germanium Detector 11
4.2 Audits 12
4.3 QA/QC Reporting 12
5.0 Evaluation Results and Performance Summary 13
5.1 Decontamination Efficacy 13
5.2 Deployment and Operational Factors 15
6.0 References 19
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Tables
Table 3-1. Concrete Characterization 5
Table 3-2. Number of Coupons Included in Technology Evaluation 7
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 Am-243 Decontamination Efficacy Results 14
Table 5-2. ASG Am-243 Decontamination Efficacy Results 15
Table 5-3. Operational Factors of RRII 17
Table 5-4. Operational Factors of ASG 18
Figures
Figure 3-1. Surface finish of concrete and granite coupons 6
Figure 3-2. Demonstration of contaminant application technique 7
Figure 3-3. Small test stand 8
Figure 3-4. Rinsing and vacuuming RRII from concrete coupon 8
Figure 3-5. ASG before application, as applied to coupon, and during vacuum removal 9
in
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Abbreviations/Acronyms
Am
ANSI
ASG
Bq
°C
cm
CBRN
CMAT
DARPA
DF
DHS
DI
EAI
EPA
Eu
h
HSRP
ICP-MS
IEEE
INL
keV
mL
L
Lpm
m
m2
mm
nCi
NHSRC
NIST
NPP
%R
OEM
ORD
PE
PPE
QA
QAPP
QC
QMP
RCT
ROD
americium
American National Standards Institute
Argonne SuperGel
becquerel(s)
degree(s) Celsius
centimeter(s)
chemical, biological, radiological, and nuclear
Consequence Management Advisory Team
Defense Advanced Research Projects Agency
decontamination factor
U.S. Department of Homeland Security
de-ionized
Environmental Alternatives, Inc.
U.S. Environmental Protection Agency
europium
hour(s)
Homeland Security Research Program
inductively coupled plasma mass-spectrometry
Institute of Electrical and Electronics Engineers
Idaho National Laboratory
kilo electron volts
milliliter(s)
liter(s)
liters per minute
meter(s)
square meter(s)
millimeter(s)
nanoCurie(s)
National Homeland Security Research Center
National Institute of Standards and Technology
nuclear power plant
percent removal
Office of Emergency Management
Office of Research and Development
performance evaluation
personal protective equipment
quality assurance
Quality Assurance Project Plan
quality control
Quality Management Plan
radiological control technician
radiological dispersion device
IV
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RML Radiological Measurement Laboratory
RRII Rad-Release II
RSD relative standard deviation
Th thorium
TTEP Technology Testing and Evaluation Program
v
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Executive Summary
The U.S. Environmental Protection Agency's (EPA's) Homeland Security Research
Program (HSRP) is helping to protect human health and the environment from adverse
impacts resulting from Chemical, Biological, Radiological and Nuclear (CBRN)
contamination whether it results from an intentional act (for instance, terrorism) a
criminal act or an unintentional act, (such as a natural disaster or industrial accident).
One way HSRP helps to protect human health and the environment is by carrying out
performance tests on technologies relevant to homeland security. Through its Technology
Testing and Evaluation Program (TTEP), HSRP recently evaluated the performance of
Environmental Alternatives, Inc.'s Rad-Release II (RRII) and Argonne National
Laboratory's SuperGel (ASG) intended specifically for decontamination of radiological
contamination. These technologies were evaluated for their ability to decontaminate
surfaces contaminated with radioactive americium from the surface of unpainted concrete
and split face granite such as might result from terrorist use of a radiological dispersion
device (RDD) or from a Nuclear Power Plant (NPP) accident.
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 Am-243 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 50 nanoCuries (nCi) of Am-243, measured by gamma spectroscopy.
For the concrete coupons, the %R was determined to be 88 ± 5% for RRII and 67 ± 9%
for ASG. For the granite coupons, the %R for Am-243 was determined to be 51 ± 3% for
RRII and 34 ± 2% for ASG.
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 waiting 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 of the
surface finishes of the concrete or the granite coupons were visibly affected by either of
the decontamination technologies.
VI
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1.0 Introduction
The U.S. Environmental Protection Agency's (EPA's) Homeland Security Research Program
(HSRP) is helping to protect human health and the environment from adverse effects resulting
from intentional and unintentional environmental contamination by chemical, biological,
radiological or nuclear (CBRN) materials. With an emphasis on decontamination and
consequence management, water infrastructure protection, and threat and consequence
assessment, HSRP is working to develop tools and information that will help detect the
intentional introduction of CBRN contaminants in indoor and outdoor environments and water
systems, the containment of these contaminants, the decontamination of buildings and/or water
systems, and the disposal of material resulting from cleanups.
The HSRP, 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. TTEP provides high-quality information that
is useful to decision makers in purchasing or applying the evaluated 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 evaluation design so that useful performance information is produced for
each of the technologies evaluated.
Through TTEP, the HSRP evaluated the decontamination efficacy of two separate technologies:
1) Environmental Alternatives, Inc.'s (EAI) Rad-Release II (RRII); and 2) Argonne National
Laboratory's SuperGel (ASG) for decontamination of radioactive americium (Am)-243 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, 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 defined as the extent of radionuclide removal following
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application of the two decontamination technologies to concrete and granite coupons to
which Am-243 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 October 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. The 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 the substrates. This process was developed to be used in sequence
to synergistically remove the contaminants via the migration pathways and pores 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 can be applied 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 well suited to
smaller applications and applications where waste minimization is a critical factor. Several
options are available to facilitate the removal step including vacuuming (as used in this
evaluation), 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 followed by removal of 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 contaminant removal
levels are achieved. More information is available at www.eai-inc.com [accessed 4/1/2013].
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2.2 Argonne SuperGel
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 for ASG
disposal until it is used to decontaminate surfaces contaminated with radionuclides
(contaminated ASG may need to be disposed of as low level radioactive waste).
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 smooth-surface applications, a squeegee attachment is
recommended.
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3.0 Experimental Details
3.1 Experimental Preparation
3.1.1 Test Coupons
Concrete coupons were prepared in a single batch of concrete made from Type II Portland
cement. The 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 C1501 requirement for Type II Portland cement specifies
that tricalcium 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% tricalcium 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 Aluminoferrite 8.7
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 allow 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
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. This concrete was judged to be representative
of exterior concrete commonly found in urban environments in the United States as shown by
INL under a previous 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,
Massachusetts) that is pinkish gray with areas of black and white. The surface finish of the
granite coupons was that of a split-face granite, a rugged, uneven finish produced by splitting
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granite with shims, wedges, or hydraulics. This type of granite has been used in the U.S.
National Archives Building, the Smithsonian, and the U.S. Department of the Interior Building
in Washington, DC. Figure 3-1 shows the surface texture of both the concrete and granite
coupons.
Figure 3-1. Surface finish of concrete and granite coupons.
3.1.2 Coupon Contamination
Am-241 is one of the radionuclides of concern as potentially attractive for use in an RDD. The
experimental methods traditionally used by NHSRC for decontamination efficacy evaluations
involve measuring contamination using the gamma signature of the radionuclide of concern.
However, Am-241 does not exhibit a gamma signature of sufficient strength to allow accurate
measurement at the levels representative of those expected for an urban radiological dispersion
device (RDD) scenario. However, Am-243, which does have a significant gamma signature, is
chemically similar to Am-241, and so was selected as the isotope for this experiment. This
allowed for measurement by gamma spectroscopy resulting in a more accurate measurement of
the level of contamination than would use of a chemical method, such as inductively coupled
plasma-mass spectrometry (ICP-MS), which would have required a contaminant concentration
significantly higher than would be realistic. In addition, the high contaminant concentration
required by the use of Am-241 would have resulted in a health and safety concern that would
have been prohibitive. Table 3-2 describes the number of coupons used in this evaluation. All of
the coupons were contaminated with 2.5 milliliters (mL) of unbuffered, slightly acidic aqueous
solution containing approximately 20 nanoCurie (nCi)/mL Am-243 which corresponds to an
activity level of approximately 50 nCi per coupon (± 5 nCi). In the case of an actual RDD, event
dry contaminated particles would be expected to settle over a wide area of a city. Application of
the contaminant in an aqueous solution was justified because from an experimental standpoint,
the ability to apply liquids homogeneously across the surface of the 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.
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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
2
Laboratory
Blanks
2
2
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 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 liters per minute (Lpm) 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
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 for 60 minutes 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 Am-243 from the surface stabilized to a
relative standard deviation (RSD) of less than 2%. The gamma emission energy of 74.66 keV
(characteristic of Am-243) was used to identify and measure the activity level of Am-243. To
protect against possible interfering radionuclides (not observed during this work), the product of
an Am-243 alpha decay (Np-239 with a gamma emission energy of 277.6 keV) was also
monitored to confirm the presence of Am-243. Gamma-ray spectra acquired from contaminated
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coupons were analyzed using INL's 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 QAPP, was employed and certified results
were provided. The minimum detectable level of Am-243 ranged from 0.2 to 0.4 nCi.
3.1.4 Surface Construction Using Test Stand
Because Am-243 is an alpha emitter, there are additional health and safety concerns (compared
with use of beta emitters like cesium and cobalt) that were taken into account by the radiological
control technicians (RCTs) and the INL and Portage staff to
minimize the possibility of personnel contamination. One
control measure was use of a small test stand (Figure 3-3)
inside of a radiological hood to hold the coupons. Ten
coupons (four concrete, four granite, one concrete blank, and
one granite blank) were decontaminated together. The five
concrete coupons were placed on the left, with the
uncontaminated blank in the lower left position (Figure 3-3).
The five granite coupons were placed on the right, with the
uncontaminated blank in the lower right position. The blank
coupons were included to observe the extent of cross
contamination caused by the decontamination activities
performed on adjacent coupons.
3.2 Decontamination Technology Procedures
Figure 3-3. Small test
stand.
3.2.1 EAIRRII
Figure 3-4. Rinsing and vacuuming
RRII from concrete coupon
The application of RRII onto the 10 coupons was
performed using plastic spray bottles (32 oz. Heavy
Duty Spray Bottle, Rubbermaid Professional, Atlanta,
GA) as directed by EAI staff via email directions. The
coupons were thoroughly wetted with RRII 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 ten minutes. The additional 1-2 sprays of
RRII Formula 1 were performed to simulate foam collapse, i.e., the reintroduction of fresh
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solutions to the contaminated matrix, as would be observed if RRII were to be deployed as a
foam for larger scale applications. After the 30-minute dwell time, the coupon surfaces were
thoroughly wetted with a 10% nitric acid rinse solution in deionized (DI) water using another
spray bottle. The surface was then vacuumed (vacuum unit "Little Green", Bissell, Grand
Rapids, MI) which took about 30 seconds per coupon. The above procedure was repeated using
RRII Formula 2. Altogether, the RRII procedure took 79 minutes to complete for ten 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 DI water as directed by Argonne staff
members via emailed written instruction and phone conversations. The mixture was then stirred
with a drill equipped with a mixing tool until the mixture was homogeneous. The
manufacturer's instructions called for application with either a plastic spatula/spackling knife, or
paintbrush. For this application the ASG was applied approximately six millimeters (mm) thick
to the ten coupons using a four inch paintbrush. The specifications of the paint brush were not
critical as a perfectly smooth application was not required. A total of two one-liter containers of
ASG were applied to the surface of the ten coupons. Altogether, the application and removal of
the ASG to the ten coupons required approximately 103 minutes, which included one minute per
coupon to apply the gel, a residence time on the surface for 90 minutes, and removal with a wet-
vacuum (Little Green, Bissell, Grand Rapids, MI) 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.
3.3 Decontamination Conditions
The decontamination technology testing was performed over the course of two days. Table 3-3
presents the number of days between coupon contamination and decontamination, the
temperature in degrees Celsius (°C) and the percent relative humidity measured during the
evaluation.
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Table 3-3. Decontamination Conditions
Time Between Temperature Relative Humidity
Coupon During During
Contamination and Decontamination Decontamination
Technology Contaminant Decontamination (°C) (%)
RRII Am-243 14 days 21.1 16-20
ASG Am-243 15 days 18.9 16
10
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4.0 Quality Assurance/Quality Control
QA/QC procedures were performed in accordance with the QMP and the QAPP 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 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). The Am-243 measurements were made using 74.66
keV to identify and quantify Am-243 with confirmation by the 277.6 keV line of the daughter
Np-239. Table 4-1 presents the calibration results across the duration of the project, consisting
of the difference between the known energy levels and those measured following calibration
(rolling average across the six most recent calibrations). 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
October 20 12
Date Range
10-2-20 12 to
11-13-2012
Energy 1
238.632
-0.004
Calibration
Energy 2
583.191
0.012
Energy Levels in keV
Energy 3
860.564
-0.028
Energy 4
1620.735
-0.222
Energy 5
2614.511
0.021
Gamma ray counting was performed for each coupon, both for initial and final activity levels,
until the activity level of Am-243 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.
The background activity of laboratory blank coupons was determined at the start of the
experiment by analyzing four arbitrarily selected coupons from the stock of concrete and granite
11
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coupons used for this evaluation. The ambient activity level of these coupons was measured for
one hour. No activity was detected above 0.3 nCi for Am-234 on these coupons.
Throughout the evaluation, a second measurement was taken on two coupons to provide
duplicate measurements to evaluate the repeatability of the instrument. One of the duplicate
measurements was performed after contamination but prior to application of the decontamination
technologies, and one was performed after decontamination. Both of the duplicate pairs showed
percent difference in activity level of 3% or less, below the acceptable percent difference of 5%.
4.2 Audits
4.2.1 Performance Evaluation Audit
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 becquerels, 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
November
2012
Eu-152
(keV)
Average
122
779
1408
NIST Activity
(Bq)
124,600
124,600
124,600
124,600
INL RML
Result (Bq)
121,600
118,800
120,700
121,500
Difference
0.49%
1.45%
1.77%
1.35%
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 data undergoing
the audit were checked. No significant findings were noted.
4.3 QA/QC Reporting
Each assessment and audit was documented in accordance with the QAPP 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 = (l-Af/A0) x 100% and DF = A0/Af
where A0 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 %R.
5.1.1 RRII Results
Table 5-1 presents the decontamination efficacy, expressed as both %R and DF for RRII when
decontaminating Am-243 from concrete and granite coupons. The target activity for each of the
contaminated coupons (pre-decontamination) was between 43 nCi and 56 nCi. The overall (both
RRII and ASG included) average activity (plus or minus one standard deviation) of the Am-243-
contaminated coupons was 50 ± 5.5 nCi, a variability of 11%. The decontamination efficacies of
RRII in terms of %R were 88 ± 5% for the concrete surfaces and 51 ± 3% for the granite
surfaces. A paired t-test was performed to determine the likelihood that results for each surface
were the same. The %R of Am-243 by RRII from concrete was significantly different (higher)
from the %R from granite at the 95% confidence interval (p=0.0022).
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.
Both concrete and granite coupons were used as cross contamination blanks. These coupons
were not contaminated, and the pre-decontamination activity measurements indicated extremely
low background levels (below the detection limit) of activity. The cross contamination blank
coupons were decontaminated using RRII along with the other contaminated coupons. The post-
decontamination measurements of activity on these blanks were 1.3 nCi for concrete, and 0.55
nCi for granite. The cross contamination was therefore minimal (1-2% of pre- decontamination
activities) but still detectable, and enough to note that the possibility exists of cross
contamination to locations previously not contaminated when using RRII in a wide area
application.
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Table 5-1. RRII Am-243 Decontamination Efficacy Results
Surface
Material
Concrete
Avg
RSD
Granite
Avg
RSD
Pre- Decontamination
Activity
(nCi/Coupon)
56
53
55
54
55
1
46
43
47
43
45
2
Post- Decontamination
Activity
(nCi/Coupon)
9.2
3.2
9.0
5.9
6.8
2.9
21
21
22
23
22
1
%R
84%
94%
84%
89%
88%
5%
54%
51%
53%
46%
51%
3%
DF
6.1
17
6.1
9.2
9.5
4.9
2.2
2.1
2.1
1.9
2.1
0.1
5.1.2 ASG Results
Table 5-2 presents the decontamination efficacy expressed as both %R and DF for ASG when
decontaminating Am-243 from concrete and granite coupons. The target activity for each of the
contaminated coupons (pre-decontamination) was between 42 nCi and 56 nCi. The overall (both
RRII and ASG included) average activity (plus or minus one standard deviation) of the Am-243-
contaminated coupons was 50 ± 5.5 nCi, a variability of 11%. The decontamination efficacies of
ASG in terms of %R were 67 ± 9% for the concrete surfaces and 34 ± 2% for the granite
surfaces. A paired t-test was performed to determine the likelihood that results for each surface
were the same. The %R of Am-243 by ASG from concrete was significantly different (higher)
from the %R from granite at the 95% confidence interval (p=0.0025).
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Table 5-2. ASG Am-243 Decontamination Efficacy Results
Surface
Material
Concrete
Granite
Pre- Decontamination
Activity
(nCi/Coupon)
52
56
51
42
Avg 50
RSD 6
47
53
42
48
Avg 48
RSD 5
Post-Decontamination
Activity
(nCi/Coupon)
10
21
18
16
17
5
30
36
28
32
32
3
%R
80%
62%
65%
62%
67%
9%
36%
32%
33%
33%
34%
2%
DF
5.0
2.6
2.8
2.6
3.3
1.2
1.6
1.5
1.5
1.5
1.5
0.04
As with 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. Both concrete and granite coupons were
used as cross contamination blanks. These coupons 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
contaminated coupons. The post-decontamination measurements of activity on these blanks
were below the detection limit for the concrete coupon and 0.36 nCi (detection level for that
coupon was 0.2 nCi) for the granite coupon. The cross contamination was therefore minimal
(less than 1% of the pre-decontamination activity) during application of ASG.
5.2 Deployment and Operational Factors
Throughout the evaluation, technicians were required to use personal protective equipment (PPE)
such as shoulder length gloves because the work was performed in a radiological hood using
Am-243. Whenever radiological material is handled, appropriate PPE is required and any waste
(e.g., from removal of RRII and ASG from the coupon surfaces) will likely be considered low
level radioactive waste and need to be disposed of accordingly. The requirement for this level of
PPE was not driven by the use of the decontamination technologies, which do not require use of
the extensive PPE, but rather by the presence of Am-243.
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, the two
formulas were applied using the identical procedure which included a 30-minute dwell time for
15
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each. The total elapsed time for the ten coupons decontaminated with RRII was approximately
79 minutes. The 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 rate. In addition, larger vacuum heads would be used for
removal. RRII did not cause any visible damage to the surface of the coupons. However, the
coupons appeared to have a thin layer of dried residual RRII Formula II remaining on the surface
after the final rinse, vacuum removal, and overnight drying. RRII was collected entirely by the
wet vacuum and the content of the vacuum canister was solidified in super-absorbing polymer
for ease of disposal as a dry granular mixture. Table 5-3 provides some additional detail about
certain operational factors for RRII as observed during the use of this experimental setup/test
stand with relatively small concrete coupons.
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 and consistency of cooked oatmeal but was
very "slippery" and tended to slide off a plastic spatula. Therefore the paintbrush was used to
apply the ASG (approximately 6 mm thick) to the coupons. However, once on the concrete, ASG
adhered rather well. Altogether, the application of ASG took approximately 30 seconds per
coupon and removal with a wet vacuum took approximately 50 seconds per coupon. The total
elapsed time for the 10 coupons decontaminated with ASG was approximately 100 minutes. If
ASG were to be applied to larger surfaces, larger application tools such as large sprayers would
likely be used which would impact the application rate. In addition, larger vacuum heads would
likely be used for removal. ASG caused no visible damage to the surface of the coupons. Table
5-4 provides some additional detail about certain operational factors for ASG as observed during
the use of this experimental setup/test stand with relatively small concrete and granite coupons.
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Table 5-3. Operational Factors for 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 as would be used 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 20 seconds per coupon. This
process was repeated for RRII Formula 2. In all, the application and removal steps
took 19 minutes in addition to the two 30 minutes dwell times for RRII. Aside from
the dwell times, this process corresponds to a decontamination rate of approximately
0.7 square meters (m2)/hour (h) for RRII. Estimated volumes used per application of
ten coupons (0.2 m2) included 210 milliliters (mL) RRII Formula 1, 210 mL RRII
Formula 2, and 180 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 the requirement
to keep 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 RRII 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 600 mL of liquid was applied per 10 coupons used during this
evaluation which corresponds to a waste generation rate of approximately 3 L/m2.
This generation rate would likely vary for different surface materials depending on
how much of the solutions absorb into the surfaces. RRII was collected entirely by
the wet vacuum and the content of the vacuum canister was solidified in super-
absorbing polymer for ease of disposal as a dry granular mixture.
Concrete and granite surfaces appeared undamaged, however they appeared to have a
thin layer of dried residual RRII Formula II remaining on the surface after the final
rinse, vacuum removal, and overnight drying.
RRII solutions are not sold as a stand-alone product but are available only as a
decontamination service for which the cost varies greatly from project to project.
Typical projects costs are in the approximate range of $33-$55/m2.
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Table 5-4. Operational Factors for 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 paintbrush to each coupon in
approximately 30 seconds (3 m2/h). 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 50 seconds per coupon (2 m /hr). Aside from the wait
time (which is independent of the surface area), the application and removal
rate was approximately 1 m2/h. Estimated volumes used per ten coupons
included 2 L of ASG. Overall that volume corresponds to a loading of 9 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 amounts of ASG 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. 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).
Approximately 4 L of ASG was applied per ten coupons during this
evaluation. That volume corresponds to a waste generation rate of
approximately 9 L/m2. ASG was collected entirely by the wet vacuum and the
content of the vacuum canister was solidified in super-absorbing polymer for
ease of disposal as a dry granular mixture. The final volume of waste was
approximately 4 L.
Concrete and granite surfaces appeared undamaged.
The material cost is approximately $0.30/L. This cost corresponds to
approximately $2/m2 if used in a way similar to the process used during this
evaluation. Labor costs were not calculated.
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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 [accessed 4/1/2013].
Radionuclide Detection and Decontamination Program, Broad Agency Announcement 03-
013, U.S. Department of 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).
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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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