EPA/600/R-1 6/150 June 2016
www.epa.gov/homeland-security-research
United States
Environmental Protection
Agency
&EPA
Technology Evaluation Report: Non-
Destructive Decontamination
Methodologies for Mixed Porous
Surfaces
Office of Research and Development
Homeland Security Research Program

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EPA/600/R-16/150
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Technology Evaluation Report
Non-Destructive Decontamination
Methodologies for Mixed Porous Surfaces
June 2016
United States Environmental Protection Agency
Cincinnati, Ohio 45268
Office of Research and Development
Homeland Security Research Program

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Contents
Contents	i
Disclaimer	iii
Figures/Tables	iv
Acronyms/Abbreviations	v
Acknowl edgments	vi
Executive Summary	vii
1.0 Introduction	1
2.0 Technology Description	3
2.1	DeconGel 1108	3
2.2	Rad-Release II	3
2.3	SuperGel	4
2.4	I.I 1-21	4
3.0 Experimental Details	5
3.1	Experimental Preparation	5
3.1.1	Mixed Surface Coupons	5
3.1.2	Coupon Contamination	7
3.1.3	Measurement of Activity on Coupon Surface	8
3.1.4	Surface Coupon Placement on Test Stands	9
3.2	Decontamination Technology Procedures	9
3.2.1	DeconGel	9
3.2.2	Rad-Release II	10
3.2.3	SuperGel	10
3.2.4	I.I 1-21	11
3.3	Decontamination Conditions	11
4.0 Quality Assurance/Quality Control	12
4.1	Intrinsic Germanium Detector	12
4.2	Audits	13
4.2.1	Performance Evaluation Audit	13
4.2.2	Technical System Audit	13
4.2.3	Data Quality Audit	14
4.3	QA/QC Reporting	14
5.0 Evaluation Results and Performance Summary	14
5.1 Decontamination Efficacy	14
5.1.1	DeconGel Results	15
5.1.2	RRII Results	17
5.1.3	SuperGel Results	18
5.1.4	I.I 1-21 Results	20
5.1.5	Results by Surface Materials	21
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5.2 Deployment and Operational Factors	22
5.2.1	DeconGel	22
5.2.2	RRII	23
5.2.3	SuperGel	23
5.2.4	I.I 1-21	24
6.0 References	26
Appendix 1	27
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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. The document was prepared by Battelle Memorial Institute under EPA
Contract No. EP-C-11-038; Task Order 19. This document was reviewed in accordance with
EPA policy prior to publication. Note that approval for publication does not signify that the
contents necessarily reflect the views 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:
Ms. Kathy Hall
National Homeland Security Research Center
Office of Research and Development
U.S. Environmental Protection Agency
26 West Martin Luther King Dr.
Cincinnati, OH 45268
513-569-7484
hall.kathy@epa.gov
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FIGURES
Figure 3-1. Examples of mixed surface coupons	6
Figure 3-2. Demonstration of contaminant application technique	8
Figure 3-3. Containment tent (outer view) and inner view with large and small test stands
containing contaminated coupons	9
Figure 3-4. Wet DeconGel and DeconGel removal	9
Figure 3-5. Rinsing and vacuuming RRII from brick coupon	10
Figure 3-6. SuperGel before Application, as applied to coupon, and during vacuum removal... 11
Figure A-l. Efficacy by surface and technology	28
Figure A-2. Efficacy by technology and surface	28
Figure A-2. Efficacy by technology and surface	28
TABLES
Table 3-1. Description of Surface Materials	5
Table 3-2. Number and Type of Contaminated Coupons Used for Each Technology Tested	7
Table 4-1. Calibration Results - Difference from Th-228 Calibration Energies	12
Table 4-2. NIST-Traceable Eu-152 Activity Standard Check	14
Table 5-1. DeconGel Cs-137 Decontamination Efficacy Results	16
Table 5-2. RRII Cs-137 Decontamination Efficacy Results	18
Table 5-3. SuperGel Cs-137 Decontamination Efficacy Results	19
Table 5-4. LH-21 Cs-137 Decontamination Efficacy Results	20
Table 5-5. Decontamination Efficacy Technologies Ranked by Coupon Surface	21
Table 5-6. Operational Factors of DeconGel	22
Table 5-7. Operational Factors of RRII	23
Table 5-8. Operational Factors of SuperGel	24
Table 5-9. Operational Factors of LH-21	25
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Abbreviations/Acronyms
%R	percent removal
ANSI	American National Standards Institute
Bq	Bequerel
°C	degrees Celsius
cm	centimeter
Cs	cesium
DARPA	Defense Advanced Research Projects Agency
DF	decontamination factor
EAI	Environmental Alternatives, Inc.
EPA	U.S. Environmental Protection Agency
Eu	europium
g	gram
HSRP	Homeland Security Research Program
IEEE	Institute of Electrical and Electronics Engineers
INL	Idaho National Laboratory
keV	kilo electron volts
L	liter
mL	milliliter
m	meter
|iCi	microcurie
nCi	nanocurie
NIST	National Institute of Standards and Technology
ORD	Office of Research and Development
PE	performance evaluation
PPE	personal protective equipment
QA	quality assurance
QAPP	quality assurance project plan
QC	quality control
RDD	radiological dispersion device
RML	Radiological Measurement Laboratory
RPD	relative percent difference
RRII	Rad-Release II
RSD	relative standard deviation
SG	SuperGel
STREAMS	Scientific, Technical, Research, Engineering and Modeling Support
Th	thorium
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ACKNOWLEDGMENTS
This document was developed by the U.S. Environmental Protection Agency's (EPA) Homeland
Security Research Program (HSRP) within EPA's Office of Research and Development. Kathy
Hall was the project lead for this document. Contributions of the following individuals and
organizations to the development of this document are acknowledged.
United States Environmental Protection Agency
Kathy Hall, National Homeland Security Research Center
Eletha Brady-Roberts, National Homeland Security Research Center
John Griggs, National Analytical Radiation Environmental Laboratory
Scott Hudson, Chemical, Biological, Radiological, and Nuclear Consequence
Management Advisory Division
Mario Ierardi, Office of Resource Conservation and Recovery
Sangdon Lee, National Homeland Security Research Center
Battelle Memorial Institute
United States Department of Energy's Idaho National Laboratory
Portage, Inc.
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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 intentional or unintentional releases of chemical, biological, radiological and nuclear
contamination. One way the HSRP helps to protect human health and the environment is by
performance testing homeland security technologies. The HSRP recently evaluated the
performance of CBI Polymers' DeconGel™ 1108, Environmental Alternatives, Inc.'s (EAI's)
Rad-Release II (RRII), Environmental Alternatives, Inc.'s SuperGel, and Intek Technologies'
LH-21. The objective of evaluating these technologies was to test their ability to remove
radioactive cesium (Cs)-137 from the mixed building material coupons of brick with mortar, tile
with grout, granite with mortar, all mortar and all grout coupons.
Prior to the application of each decontamination technology, 15 centimeter (cm) x 15 cm
coupons were contaminated with liquid aerosols of Cs-137 and placed in a vertical test stand.
Following manufacturers' recommendations, the decontamination technologies were applied to
all of 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, SuperGel, DeconGel, and Intek LH-2 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 DeconGel, RRII, SuperGel, and Intek LH-21 was evaluated following contamination
of the coupons with approximately 1 microcurie (|iCi) Cs-137 measured by gamma
spectroscopy. Appendix I summarizes these data graphically.
For the brick with mortar coupons, the %R values for Cs-137 were determined to be:
. 71% ± 1% for DeconGel
. 44% ± 3% for RRII
48%) ± 2% for SuperGel
. 40% ± 1 % for Intek LH-21
For the tile with grout coupons, the %>R values for Cs-137 were determined to be:
• 92% ± 2% for DeconGel
. 95% ± 2% for RRII
82%) ± 5%> for SuperGel
. 87% ±2% Intek LH-21
For the granite with mortar coupons, the %>R values for Cs-137 were determined to be:
. 73% ± 8% for DeconGel
. 74% ± 1% for RRII
40%) ± 3% for SuperGel
. 51 % ± 6% for Intek LH-21
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For the mortar coupons, the %R values for Cs-137 were determined to be:
•	58% ± 10% for DeconGel
. 48% ± 8% for RRII
39% ± 5% for SuperGel
. 26% ± 6% for Intek LH-21
For grout coupons, the %R values were determined to be:
•	43% ± 3% for DeconGel
. 60% ± 11% for RRII
36% ± 4% for SuperGel
. 3 5% ± 7% for Intek LH-21
Deployment and Operational Factors: DeconGel and SuperGel were applied as gels.
DeconGel was removed by peeling and SuperGel was removed by vacuuming. RRII and LH-21
were applied as liquids and removed with an aqueous rinse and vacuum.
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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 impacts resulting
from chemical, biological, radiological and nuclear (CBRN) contamination. Both planning and
protection are required whether the contamination were to result from an intentional act such as
terrorism or crime, an unintentional act such as an industrial accident, or a natural disaster. With
an emphasis on decontamination and consequence management, water infrastructure protection,
and threat and consequence assessment, the HSRP is working to develop tools and information
that will help detect the intentional introduction of CBRN contaminants in buildings or water
systems, the containment of these contaminants, the decontamination of buildings and/or water
systems, and the management of wastes generated from decontamination and cleanup operations.
The National Response Framework, Nuclear/Radiological Annex, published in June of 2008,
designated EPA as a coordinating agency for long-term recovery following an intentional act, an
unintentional act, or a natural disaster involving the release of radioactive materials. Consistent
with EPA's legislated mission, this directive makes EPA the coordinating agency for the
environmental response following releases of radiological materials which impact non-coastal
private property. To meet the expected technology needs associated with radiological
contamination, EPA's Office of Research and Development (ORD), the HSRP, is conducting
decontamination technology evaluations. These technology evaluations provide data to be used
in support of decisions concerning the selection and use of decontamination technologies for
buildings contaminated with radiological threat agents. The decontamination efficacy (results in
this report) of four separate technologies was evaluated, which included SuperGel (SG)
(Environmental Alternatives, Inc. [EAI], Keene, NH), Rad-Release II (RRII; Environmental
Alternatives, Inc., Keene, NH), DeconGel (CBI Polymers, Honolulu, HI), and LH-21 (Intek
Marine Technology, Fairfax, VA). During this evaluation, the decontamination technologies
were applied to surfaces made from mixed porous surfaces that represent high-value urban
infrastructure. Surfaces include brick with mortar (simulating buildings), tile with grout
(simulating subway tunnels), and granite pieces held together with mortar. In addition, separate
coupons were also prepared with a complete covering of grout and mortar to evaluate these
porous materials individually. Cesium-137 (Cs-137) was the contaminant that was used
exclusively during this evaluation.
This evaluation was conducted according to the EPA Quality Assurance Program. The following
performance characteristics of DeconGel, RRII, SuperGel, and LH-21 were evaluated:
•	Decontamination efficacy defined as the extent of radionuclide removal following
application of the four decontamination technologies to mixed brick/mortar, mixed
tile/grout, mixed granite/mortar, grout and mortar coupons to which Cs-137 had been
applied.
•	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
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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 (1).
This technology evaluation took place from November 2014 (coupon preparation) through
March 2015 (completion of activity measurements) at the U.S. Department of Energy's Idaho
National Laboratory (INL). Quality assurance (QA) oversight of this evaluation was provided by
Battelle and EPA. The Battelle QA officer conducted a technical systems audit and an audit of
data quality on the results from the evaluation.
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2.0 Technology Description
This report provides results for the evaluation of DeconGel 1108, RRII, SuperGel, and LH-21.
Following is a description of each technology based on information provided by the vendors.
The information provided below was not verified during this evaluation.
2.1	DeconGel 1108
DeconGel 1108 (hereafter referred to as DeconGel) is a strippable coating designed for safely
removing radioactive contamination or as a covering to contain contamination. DeconGel is sold
as a paint-like formulation. Application options include use of a paint brush, roller, or sprayer.
The water-based wet coating (hydrogel) can be applied to horizontal, vertical or inverted surfaces
and can be applied to most surfaces including bare, coated and painted concrete, aluminum, steel,
lead, rubber, plastic sheeting, wood, porcelain, tile grout, and vinyl, ceramic and linoleum floor
tiles. Following application, the coating requires approximately 12 hours to cure prior to
removal. When dry, the product binds the contaminants into a polymer matrix. The dried
coating containing the encapsulated contamination can then be peeled off the surface and
disposed. More information is available at www.decongel.com.
2.2	Rad-Release II
The RRII decontamination technology is a chemical process involving 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 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 residual contaminant levels are achieved. More
information is available at http://www.eai-inc.com/Nuclear/rad-release.html.
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2.3	SuperGel
SuperGel 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 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, SuperGel 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
low toxicity reagents and low volume radioactive waste
The super absorbing 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 to
20 grams [g] of ionic wash solution per g 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 to 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. Prior to use to decontaminate a surface containing hazardous material, the hydrogel is not
in and of itself considered a hazardous material. However, after use for decontamination, the
new mixture of hydrogel and contaminant may then be considered hazardous and would have to
be disposed of accordingly.
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.
2.4	LH-21
LH-21 is a non-corrosive cleaning product developed to remove concrete from equipment. It
effectively and rapidly removes concrete, without damaging painted surfaces, aluminum, steel,
synthetic or composite materials. It also removes lime scale and other mineral deposits. LH-21
is used at a 1:1 dilution with water and can be applied via aerosol, low-pressure foaming system,
sprayer, or brush and bucket. Light to moderate deposits usually require one application. Heavy
or aged deposits may require regular applications over a period of hours, days or weeks. A
surface is typically sprayed and brushed, then sprayed again followed by a one hour wait period;
then, it is sprayed and brushed again and the decontaminant is rinsed away. Longer wait periods
may require misting with water to maintain wetness.
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3.0 Experimental Details
3.1 Experimental Preparation
3.1.1 Mixed Surface Coupons
Mixed surface coupons used for this evaluation were approximately 15 cm x 15 cm, and 4 cm
thick. The coupons' surface finish was consistent across all of the coupons and was
representative of that which would typically be found on the exterior of an urban structure. As
mentioned previously, the mixed surfaces were made from porous surfaces that represent high-
value urban infrastructure. The surfaces included brick with mortar, tile with grout, and granite
pieces held together with mortar. Cs-137 was the contaminant used exclusively during this
evaluation. Table 3-1 describes the materials that were used as urban surfaces.
Table 3-1. Description of Surface Materials
Material Type
Name
Source
Example Building
Brick with mortar
Facing Brick
Interstate Brick Company, West
Jordan, UT
Urban building
Tile with grout
Semplice™ Glossy
Emser Tile, Salt Lake City, UT
Subway tunnel
Granite with mortar
Milford Pink
Milford, MA
National Archives Building
Mortar
Mortar Mix
Quikrete (Atlanta, GA)
Not applicable
Grout
Polyblend®
Custom Building Products (Seal
Beach, CA)
Not applicable
Surface material coupon generation. In order to maintain methods as similar as possible to
previous technology evaluations, the mixed surface material (i.e., tile, brick, or granite) coupon
surface area was approximately 15 cm x 15 cm. To make these mixed porous surfaces, pieces of
each surface material were obtained in sizes smaller than 15 cm x 15 cm so more than one piece
of material was assembled with mortar or grout to make a mixed surface of that size. No matter
the surface material, Battelle put two or three of the smaller coupon pieces together with a rigid
backing (to prevent separation) and joined together mortar or grout to make mixed surfaces. The
mixed surfaces were assembled 2 to 3 months before use for decontamination testing. The
efficacy of contaminant removal from the grout and mortar was studied by making coupons with
surfaces that were made completely from the grout and mortar. For the brick mortar (used for
the brick and granite mixed coupons), Battelle and INL built a form that was 15 cm x 15 cm x 3
cm and the mortar was prepared as suggested by the instructions and poured into the form. The
mortar coupons were allowed to dry for at least 72 hours and then the form was removed leaving
a complete coupon made from the dried mortar. For the tile grout, a similar form was prepared,
but large enough to hold a 15 cm x 15 cm concrete coupon plus approximately 1 cm additional
depth. The tile grout was poured into the form (on top of the concrete coupon) that, when dry,
left behind a layer of approximately 1 cm of tile grout on the surface of the concrete coupon
serving as a coupon support. Figure 3-1 shows examples of the coupons used for this evaluation.
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r

i
Figure 3-1. Examples of mixed surface coupons.
(Top row left to right: brick with mortar, granite with mortar, and tile with grout. Bottom
row: mortar [left] and grout [right]).
Prior to contaminant application, the surface of each mixed surface coupon was examined for
obvious cracks or abnormalities and, if none were found, the coupon surfaces were cleaned with
a soft nylon brush and ASTM International (ASTM) Type I water and allowed to air dry on a
laboratory bench. Each coupon was then marked with an identifying number using a permanent
marker. Between the time of coupon cleaning and labeling and contaminant application, all of
the coupons were stored in the laboratory used for contaminant application. Following
contaminant application, the coupons were stored in a drum used for transporting the coupons to
and from the Radiological Measurement Laboratory (RML) located at the Idaho National
Laboratory facility. All of the coupons experienced the same environmental conditions,
minimizing environmental conditions as a variable to decontamination technology performance.
In addition, the decontamination experiments were performed in a climate controlled location
containing a radiological tent, minimizing differences in conditions during testing which was
conducted over the course of 2 weeks in February 2015.
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3.1.2 Coupon Contamination
Table 3-2 provides the number of coupons and contaminants used with each decontamination
technology during this technology evaluation. Regardless of surface type used, all of these
coupons were contaminated with 2.5 milliliter (mL) of unbuffered, slightly acidic aqueous
solution containing approximately 0.4 |iCi/mL Cs-137 which corresponds to an activity level of
approximately 1 |iCi per coupon (± 0.5 juCi). 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
from an experimental standpoint, the ability to apply liquids homogeneously across the surface
of the coupons greatly exceeds that capability for dry particles. Also, the selected
decontamination technologies are more likely to be used weeks or months after a radiological
incident. Therefore, it is expected that precipitation events are likely to have impacted the
particle bound Cs-137. The aqueous contamination was delivered to each coupon using an
aerosolization technique developed by INL. Coupons were contaminated approximately 2 weeks
before use.
Table 3-2. Number and Type of Contaminated Coupons Used for Each Technology Tested
Technology
Surface
Contaminant
Coupons

Brick with mortar

4

Tile with grout

4
SuperGel
Granite with mortar
Cs-137
4

Grout

4

Mortar

4

Brick with mortar

4

Tile with grout

4
RRII
Granite with mortar
Cs-137
4

Grout

4

Mortar

4

Brick with mortar

4

Tile with grout

4
DeconGel™
Granite with mortar
Cs-137
4

Grout

4

Mortar

4

Brick with mortar

4

Tile with grout

4
LH-21
Granite with mortar
Cs-137
4

Grout

4

Mortar

4
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 to 2 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 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 epoxy) to
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ensure 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 m L 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 four decontamination technologies
using an intrinsic high purity germanium detector (Canberra LEGe Model GL 2825 R/S,
Meriden, CT). After each coupon was placed in front of the detector face, gamma ray spectra
were collected until the average measured activity level of Cs-137 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 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. Gamma counting by RML was conducted to meet quality
assurance and control requirements and certified results were provided to the project manager.
The minimum detectable level for Cs-137 was 0.2 nanocurie (nCi) on these coupons.
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3.1.4 Surface Coupon Placement on Test Stands
To evaluate the decontamination technologies on vertical surfaces (simulating walls)
contaminated with Cs-137, three test stands were used for testing. A stainless steel test stand
(2.7 meters [m] >< 2.7 m) designed to hold three rows of coupons was used for the brick with
mortar and tiles with grout coupons. Smaller test stands were used for the granite with mortar
coupons as well as the mortar and grout coupons. Figure 3-3 shows the contamination tent and
both types of test stands. The middle position of the middle row contained an uncontaminated
blank coupon in the large test stand. A blank coupon was positioned at the bottom middle of the
smaller grey and white test stands. These blank coupons were 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.
Figure 3-3. Containment tent (outer view) and inner view with large and small test
stands containing contaminated coupons.
3.2 Decontamination Technology Procedures
3.2.1 DeconGel
The implementation of the DeconGel technology procedure included application of two coats of
DeconGel followed by removal of the dried coating. The application was performed using a
standard 6-inch paint brush. The specifications of the paint brush were not critical as a perfectly
smooth application was not required. The paint brush was loaded with the wet coatings by
dipping the brush into a plastic container containing the wet coatings and then the wet coatings
Figure 3-4. Wet DeconGel and DeconGel removal.
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were applied generously until the entire surface of the coupon was covered. The paint brush was
then used to work the wet coating into the surfaces. The brush was then used to smooth the
applied wet DeconGel on each coupon. If areas of the coupons were not covered completely,
additional wet DeconGel was added. The first coat of the DeconGel was allowed to set for two
hours and a second coat was added on top of the initial coat following the same method. The
coupons with the wet DeconGel were allowed to dry overnight. The dry coatings were removed
by first scoring the bottom edge of the coupons (now covered with dried coatings) with a plastic
knife to free corners of the dried coating so they could be pulled off the surface by hand. These
steps were repeated a second time before post-decontamination activity measurement. Figure 3-
4 shows a granite coupon just after DeconGel application and the removal of dry DeconGel.
3.2.2	Rad-Release II
The application of RRII was performed using plastic spray bottles (32-oz heavy duty spray
bottle, Rubbermaid Professional, Atlanta, GA). The coupons were thoroughly wetted with RRII
Formula 1 with three to four 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 15 to 20 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 one to two sprays of additional RRII
Formula 1 approximately every 5 minutes. The
additional one to two 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
applications. After the 30-minute dwell time, the
coupon surfaces were thoroughly wetted with a
10% nitric acid rinse solution (in deionized water)	_ n. . ,
' Figure 3-5. Rinsing and vacuuming
using another spray bottle. The surface was then	t»t»tt e ™ u • i
~	RRII from brick coupon.
vacuumed (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
(including all the steps above) took 79 and 72 minutes to complete for the two sets of coupons
that were decontaminated during this technology evaluation. Figure 3-5 shows the rinse and
vacuuming step of the RRII procedure.
3.2.3	Super Gel
The SuperGel was prepared by mixing two dry powders with water as directed by the vendor.
The mixture was then stirred with a drill equipped with a mixing tool until the mixture was
homogeneous. The SuperGel was applied using a 4-inch paint brush to smooth the SuperGel
across the surface. The specifications of the paint brush were not critical as a perfectly smooth
application was not required. Altogether, the application of the SuperGel required approximately
20 seconds per coupon; SuperGel was allowed to stay on the surface for 90 minutes, and then
10

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EPA/600/R-16/150
June 2016
was removed with a wet vacuum (same as for RRII above), which required approximately 20
seconds per coupon. Figure 3-6 shows the application and vacuum removal steps for SuperGel.
Figure 3-6. SuperGel before Application, as applied to coupon, and during vacuum
removal.
3.2.4 LH-21
The application of LFI-21 was performed using plastic spray bottles (same as for RRII above) as
directed by Intek staff members. The LH-21 was diluted 1:1 in water prior to addition to the
spray bottles for application to the contaminated coupons. The coupons were thoroughly wetted
with LH-21 with three to four sprays. The solution was then worked into the surface of the
coupon by scrubbing the entire surface of the coupon once with a medium bristle brush. This
initial application of LH-21 took only 25 seconds for each coupon and was followed by a quick
spray to rewet the surface of the coupons. The next step was a 60-minute dwell time for LH-21
to reside on the surfaces of the coupons. The coupon surfaces were kept damp with one to two
sprays of additional LH-21 approximately every 10 minutes. After the 60-minute dwell time, the
coupon surfaces were thoroughly wetted with LH-21 and scrubbed just as they were initially.
The coupons were then rinsed with deionized water using another spray bottle. The surface was
then vacuumed which took about 25 seconds per coupon. The total elapsed time for the entire
LH-21 procedure (including all of the steps detailed above) for the nine coupons decontaminated
with LH-21 was approximately 70 minutes.
3.3 Decontamination Conditions
The decontamination technology testing was performed over the course of four days from
February 23 to 26, 2015. During the evaluation the temperature was 20 Celsius (°C) and the
percent relative humidity was 16%.
11

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EPA/600/R-16/150
June 2016
4.0 Quality Assurance/Quality Control
QA/QC procedures were performed in accordance with the EPA Quality Assurance Program 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)(2). 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. Each row shows the difference between the known energy
levels and those measured following calibration (rolling average across the six most recent
calibrations). Each row represents a 6-week rolling average of calibration results. These
energies were compared to the previous 30 calibrations to confirm that results were within three
standard deviations of the previous calibration results. All of the calibrations fell within this
requirement.
Table 4-1. Calibration Results - Difference from Th-228 Calibration Energies
Measurement
Date Range

Calibration Energy Levels (keV)

Energy 1
238.632
Energy 2
583.191
Energy 3
860.564
Energy 4
1620.735
Energy 5
2614.533
12-23-14 to
1-26-15
-0.005
-0.014
-0.022
-0.275
0.026
1-26-15 to
2-24-15
-0.005
0.013
-0.022
-0.232
0.022
2-24-15 to
3-23-15
-0.003
0.009
-0.037
-0.120
0.012
3-2-15 to
3-31-15
-0.002
0.009
-0.048
-0.089
0.010
3-10-15 to
4-14-15
-0.001
0.003
-0.013
-0.039
0.004
Gamma ray counting was continued for each coupon until the measured activity level of Cs-137
on the surface had a RSD of less than 2%. This RSD was achieved during the first hour of
counting for all of 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 by analyzing five
arbitrarily selected coupons from the stock of 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 0.2 nCi for Cs-137 on these coupons.
12

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EPA/600/R-16/150
June 2016
Throughout the evaluation, a second measurement was taken on 11 coupons to provide duplicate
measurements to evaluate the repeatability of the instrument. Five of the duplicate
measurements were performed after contamination but prior to application of the
decontamination technologies and six were performed after decontamination. Seven of the
duplicate pairs had no measureable difference in activity level, while four of the duplicate pairs
showed a relative percent difference (RPD) in activity level of < 3%. All of the duplicate
measurement results were below the acceptable RPD of 10%.
Ten transport control samples (two from each surface material) were analyzed during the
evaluation. These samples were contaminated, measured for the pre-decontamination activity,
transported to the testing facility, and then shipped back to the RML for a follow-up
measurement of activity. The activity measured before and after shipment was measured to
determine the consistency of the gamma detector. All 10 samples had RPD values of < 1.1%,
well below the acceptable RPD of 25%.
4.2 Audits
4.2.1	Performance Evaluation Audit
RML performed 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,
and for the purposes of this evaluation, served as the performance evaluation audit to confirm the
accuracy of the calibration standards used for the instrumentation critical to the results of an
evaluation. Table 4-2 provides the results of each of these audits of the detector that was used
during this evaluation. All results were within the acceptable RPD of 7%.
4.2.2	Technical System Audit
A technical systems audit was performed on February 25, 2015 to confirm compliance with
project quality requirements. The audit report was completed. One observation was that some
non-concrete coupons were used for the cross-contamination blanks (because of unavailability of
concrete coupons). There was no negative impact to this change, but it was documented as a
deviation.
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EPA/600/R-16/150
June 2016
Table 4-2. NIST-Traceable Eu-152 Activity Standard Check
Date
Eu-152 (keV)
NIST Activity (Bq)
INL RML Result (Bq)
RPD

Average
124,600
122,100
2%
January
122
124,600
119,300
4%
2015
779
124,600
117,800
5%

1408
124,600
122,700
2%

Average
124,600
122,500
2%
February
122
124,600
118,400
5%
2015
779
124,600
118,800
5%

1408
124,600
123,000
1%

Average
124,600
122,000
2%
March
122
124,600
119,200
4%
2015
779
124,600
115,900
7%

1408
124,600
121,000
3%

Average
124,600
120,600
3%
April
122
124,600
118,400
5%
2015
779
124,600
119,700
4%

1408
124,600
124,600
0%
INL, Idaho National Laboratory; RML, Radiological Measurement Laboratory; RPD, relative percent difference
4.2.3 Data Quality Audit
At least 10% of the data acquired during the evaluation were audited. The QA officer 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 were
checked for accuracy. The audit revealed three activity measurement transcription errors that
were corrected in the report and data spreadsheets.
4.3 QA/QC Reporting
Each assessment and audit was documented in accordance with project quality requirements.
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 100%
and
DF = Ao/Af
where A0 is the radiological activity from the surface of the coupon before application of the
decontamination technologies and Af is the radiological activity from the surface of the coupon
after decontamination. While the DFs are reported in the following data tables, the narrative
describing the results will focus on the %R.
While given in each of the tables below, the overall (DeconGel, RRII, SuperGel and LH-21
included) average pre-decontamination activity (plus or minus one standard deviation) of the Cs-
137 contaminated coupons was:
14

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EPA/600/R-16/150
June 2016
. 0.97 |iCi ± 0.05 |iCi for brick (6% RSD)
. 1.04 |iCi ± 0.08 |iCi for tile (8% RSD)
1.04 |iCi ± 0.04 |iCi for mortar (4% RSD)
1.04 |iCi ± 0.09 |iCi for grout (8% RSD)
. 0.92 |iCi ± 0.07 |iCi for granite (7% RSD)
The target activity for each coupon was 1 |iCi. All pre-decontamination coupons were within
0.08 |iCi of the target, within the 0.5 |iCi requirement.
5.1.1 DeconGel Results
Table 5-1 presents the decontamination efficacy, expressed as both %R and DF, for DeconGel
when decontaminating Cs-137 from the surfaces. The decontamination efficacies of DeconGel
in terms of %R for Cs-137 were:
71% ± 1% for the brick with mortar surfaces
92% ± 2% for the tile with grout surfaces
73%) ± 9% for the granite with mortar surfaces
58% ± 10%o for mortar surfaces
43%o ± 3%o for grout surfaces
Several t-tests were performed to determine the likelihood that the %>R results for each surface
were the same. The t-test results indicated the %>R from each of the surfaces contaminated with
Cs-137 were significantly different from one another at the 95%> confidence level (p-values <
0.05) with the exception of two results. Brick with mortar compared to granite with mortar and
granite with mortar compared to mortar were statistically similar. As indicated by the %>R values
above, Cs-137 was most effectively removed from the mixed surfaces of tile followed by granite
and then brick.
15

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EPA/600/R-16/150
June 2016
Table 5-1. DeconGel Cs-137 Decontamination Efficacy Results
Surface Materials

Pre-Decon Activity
(jiCi/Coupon)
Post-Decon Activity
(jiCi/Coupon)
%R
DF
Brick with

0.95
0.28
71%
3.4
Mortar

1.00
0.30
70%
3.3


1.01
0.28
72%
3.6


0.97
0.29
70%
3.3

Ave
0.98
0.29
71%
3.4

SD
0.03
0.01
1%
0.1
Tile with Grout

1.12
0.11
90%
10.2


0.94
0.083
91%
11.3


1.12
0.062
94%
18.1


1.16
0.079
93%
14.7

Ave
1.09
0.084
92%
13.6

SD
0.10
0.020
2%
3.6
Granite with

0.93
0.29
69%
3.2
Mortar

0.96
0.21
78%
4.5


0.94
0.36
62%
2.6


0.85
0.16
81%
5.3

Ave
0.92
0.25
73%
3.9

SD
0.05
0.09
9%
1.2
Mortar

1.10
0.61
45%
1.8


1.01
0.41
59%
2.5


1.00
0.32
68%
3.1


1.06
0.43
59%
2.5

Ave
1.04
0.44
58%
2.5

SD
0.05
0.12
10%
0.5
Grout

1.04
0.58
44%
1.8


1.12
0.67
40%
1.7


1.00
0.59
41%
1.7


1.09
0.57
48%
1.9

Ave
1.06
0.60
43%
1.8

SD
0.05
0.05
3%
0.1
%R, percent removal
As described above in Section 3.1.4, cross-contamination blanks were included in the test stands
during testing to evaluate the potential for cross contamination due to application of DeconGel
on wall locations above the blanks. One blank was used in the middle of the large test stand and
one was used in between the two small test stands. Each cross-contamination blank was an
uncontaminated coupon that had pre-decontamination activity measurements indicating
extremely low background levels (below the detection limit) of activity. These coupons were
decontaminated using DeconGel along with the other contaminated coupons and the post-
decontamination measurement of activity of the two blanks revealed that one blank activity was
below detection limits and the activity of the other blank was measurable at 0.051 |iCi for Cs-
137. For the one cross-contamination blank that exhibited an increase in activity, the increased
level of activity was approximately 5% 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
16

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EPA/600/R-16/150
June 2016
is a possibility when using DeconGel in a wide area application possibly from dripping wet
coating and use of the same tools for application and removal.
5.1.2 RRII Results
Table 5-2 presents the decontamination efficacy, expressed as both %R and DF, for RRII when
decontaminating Cs-137 from surface coupons. The decontamination efficacies of RRII in terms
of %R for Cs-137 were:
44% ± 3% for the brick with mortar surfaces
95% ± 2% for the tile with grout surfaces
74%) ± 1%> for the granite with mortar surfaces
48%o ± 8%> mortar surfaces
60% ± ll%o for grout surfaces
Several t-tests were performed to determine the likelihood that the %>R results for each surface
were the same. The t-test results indicated that the %>R from each of the surfaces contaminated
with Cs-137 was significantly different from one another at the 95%> confidence level (p-values <
0.05) with the exception of two results. Brick with mortar compared with mortar, granite with
mortar compared to grout, and mortar compared to grout were statistically similar. As indicated
by the %>R values above, Cs-137 was most effectively removed from the mixed surface tile
followed by granite and then brick.
As described above in Section 3.1.4, cross-contamination blanks were included in the test stand
during testing to evaluate the potential for cross contamination due to application of RRII on wall
locations above the blanks. The post-decontamination measurement of activity of the two blanks
was found to be 0.004 and 0.057 |iCi for Cs-137. This increased level of activity was less than 6%
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
possibly due to the RRII formulas running down the wall and the use of the same equipment for
application and removal.
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EPA/600/R-16/150
June 2016
Table 5-2. RRII Cs-137 Decontamination Efficacy Results
Surface Materials

Pre-Decon Activity
Post-Decon Activity
%R
DF
Brick with Mortar

0.99
0.52
47%
1.9


0.99
0.58
41%
1.7


0.94
0.55
41%
1.7


0.95
0.51
46%
1.9

Ave
0.97
0.54
44%
1.8

SD
0.03
0.03
3%
0.1
Tile with Grout

1.05
0.075
93%
14.0


1.05
0.036
97%
29.2


1.16
0.087
93%
13.3


1.02
0.035
97%
29.1

Ave
1.07
0.058
95%
21.4

SD
0.06
0.027
2%
8.9
Granite with Mortar

1.08
0.29
73%
3.7


0.89
0.23
74%
3.8


0.96
0.26
73%
3.7


0.89
0.22
76%
4.1

Ave
0.96
0.25
74%
3.9

SD
0.09
0.03
1%
0.2
Mortar

1.08
0.63
42%
1.7


1.11
0.58
48%
1.9


1.02
0.57
44%
1.8


1.00
0.40
60%
2.5

Ave
1.05
0.55
48%
2.0

SD
0.05
0.10
8%
0.4
Grout

1.10
0.61
45%
1.8


0.95
0.32
66%
3.0


1.13
0.39
65%
2.9


0.98
0.34
65%
2.9

Ave
1.04
0.42
60%
2.6

SD
0.09
0.13
11%
0.6
%R, percent removal
5.1.3 SuperGel Results
Table 5-3 presents the decontamination efficacy, expressed as both %R and DF, for SuperGel
when decontaminating Cs-137 from surface coupons. The decontamination efficacies of
SuperGel in terms of %R for Cs-137 were:
48% ± 2% for the brick with mortar surfaces
82% ± 5% for the tile with grout surfaces
40% ± 3% for the granite with mortar surfaces
39% ± 5% mortar surfaces
36% ± 4% for grout surfaces
Several t-tests were performed to determine the likelihood that the %R results for each surface
were the same. The t-test results indicated the %R from each of the surfaces contaminated with
Cs-137 were significantly different from one another at the 95% confidence level (p-values <
18

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EPA/600/R-16/150
June 2016
0.05) with the exception of three results. Granite with mortar, grout, and mortar were all
statistically similar. As indicated by the %R values above, Cs-137 was most effectively removed
from the mixed surface tile followed by brick and then granite.
A cross-contamination blank was included in the test stand during testing to evaluate the
potential for cross contamination due to application of SuperGel on wall locations above the
blanks. This coupon was decontaminated using SuperGel along with the other contaminated
coupons. The post-decontamination measurement of activity for this blank was found to be less
than detection limit of 0.0002 |iCi for Cs-137; therefore, the cross contamination was very
minimal during application of SuperGel.
Table 5-3. SuperGel Cs-137 Decontamination Efficacy Results
Surface Materials

Pre-Decon Activity
(jiCi/Coupon)
Post-Decon Activity
(jiCi/Coupon)
%R
DF
Brick with Mortar

0.93
0.49
47%
1.9


0.81
0.42
48%
1.9


1.03
0.52
50%
2.0


0.97
0.54
44%
1.8

Ave
0.94
0.49
47%
1.9

SD
0.09
0.05
2%
0.1
Tile with Grout

0.99
0.124
87%
8.0


1.00
0.166
83%
6.0


1.10
0.233
79%
4.7


1.07
0.241
77%
4.4

Ave
1.04
0.191
82%
5.8

SD
0.05
0.056
5%
1.6
Granite with Mortar

0.83
0.48
42%
1.7


0.83
0.52
37%
1.6


0.87
0.53
39%
1.6


0.90
0.51
43%
1.8

Ave
0.86
0.51
40%
1.7

SD
0.03
0.02
3%
0.1
Mortar

1.01
0.65
36%
1.6


0.99
0.57
42%
1.7


1.07
0.70
35%
1.5


1.08
0.61
44%
1.8

Ave
1.04
0.63
39%
1.6

SD
0.04
0.06
5%
0.1
Grout

1.09
0.63
42%
1.7


1.11
0.74
33%
1.5


1.07
0.71
34%
1.5


1.01
0.64
37%
1.6

Ave
1.07
0.68
36%
1.6

SD
0.04
0.05
4%
0.1
%R, percent removal
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EPA/600/R-16/150
June 2016
5.1.4 LH-21 Results
Table 5-4 presents the decontamination efficacy, expressed as both %R and DF, for LH-21 when
decontaminating Cs-137 from surface coupons. The decontamination efficacies of LH-21 in
terms of %R for Cs-137 were:
40% ± 1% for the brick with mortar surfaces
87% ± 2% for the tile with grout surfaces
51% ± 6% for the granite with mortar surfaces
26% ± 6% for mortar surfaces
35% ± 7% for grout surfaces
Several t-tests were performed to determine the likelihood the %R results for each surface were
the same. The t-test results indicated the %R from each of the surfaces contaminated with Cs-
137 were significantly different from one another at the 95% confidence level (p-values < 0.05)
with the exception of two results. Brick with mortar compared to grout, and grout compared to
mortar were statistically similar. As indicated by the %R values above, Cs-137 was most
effectively removed from the mixed surface tile followed by granite and then brick.
Table 5-4. LH-21 Cs-137 Decontamination Efficacy Results
Surface Materials

Pre-Decon Activity
(jiCi/Coupon)
Post-Decon Activity
(jiCi/Coupon)
%R
DF
Brick with Mortar

1.00
0.62
38%
1.6


0.89
0.53
40%
1.7


1.01
0.6
41%
1.7


1.00
0.6
40%
1.7

Ave
0.98
0.59
40%
1.7

SD
0.06
0.04
1%
0.03
Tile with Grout

0.97
0.112
88%
8.7


0.93
0.125
87%
7.4


0.97
0.140
85%
6.9


1.03
0.130
87%
7.9

Ave
0.98
0.127
87%
7.7

SD
0.04
0.012
2%
0.7
Granite with

1.03
0.43
58%
2.4
Mortar

0.94
0.49
48%
1.9


0.87
0.49
44%
1.8


0.94
0.43
54%
2.2

Ave
0.95
0.46
51%
2.1

SD
0.07
0.03
6%
0.3
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EPA/600/R-16/150
June 2016
Mortar

1.02
0.83
19%
1.2


1.01
0.72
29%
1.4


1.01
0.77
24%
1.3


1.01
0.67
34%
1.5

Ave
1.01
0.75
26%
1.4

SD
0.01
0.07
6%
0.1
Grout

1.02
0.70
31%
1.5


0.79
0.50
37%
1.6


1.09
0.77
29%
1.4


1.10
0 61
45%
18

Ave
1.00
0.65
35%
1.6

SD
0.14
0.12
7%
0.2
As for the above 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 LH-21 on wall locations above the blanks. These blanks were found to be 0.007
|iCi for Cs-137. This increased level of activity was less than 1% of the activity added to each of
the contaminated coupons for Cs-137. Therefore, the cross contamination was minimal but still
detectable, and enough to note that cross contamination to locations previously not contaminated
is a possibility when using LH-21 in a wide area application possibly due to the solution running
down the wall and the same equipment being used in both locations.
5.1.5 Results by Surface Materials
Hypothesis testing included use of unpaired, two-tailed, Student's t-tests at a 95% confidence
interval to determine differences in decontamination technology efficacy between different
technologies on the same surface. In all cases, the null hypothesis was that there is no difference
between the two data sets and the Student's t-test would indicate the probability of the observed
data if the null hypothesis was true. Resulting probabilities of less than 0.05 indicated
statistically significant differences between data sets.
As presented in Table 5-6, the results indicate R% for DeconGel and RRII had the highest
decontamination efficacy and were not statistically different when used on tile with grout, granite
with mortar, and mortar. DeconGel had the highest R% when used on brick with mortar and
RRII had the highest R% when used on grout. These results are presented graphically in the
appendix.
Table 5-5. Decontamination Efficacy Technologies Ranked by Coupon Surface
%R Ranking
Brick with
Tile with
Granite with
Mortar
Grout
by Surface*
Mortar
Grout
Mortar
1
DeconGel
RRII =
RRII =
DeconGel =
RRII
DeconGel
DeconGel
RRII
2
II
o
in
SG = LH-21
LH-21
RRII = SG
DeconGel =
LH-21
3
LH-21
NA
SG
SG
SG = LH-21
4
NA
NA
NA
LH-21
LH-21
indicates removal effectiveness: 1 being most effective and 4 being least effective
= indicates that the results were not statistically different
NA, not applicable; RRII, Rad-Release II SG, SuperGel
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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
Cs-137 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 needed to be 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 by
the presence of Cs-137.
5.2.1 DeconGel
A number of operational factors were documented by the operator who performed the testing
with DeconGel. The application process of DeconGel was described in Section 3.2.1 and
included use of a standard 4-inch paint brush. DeconGel did not cause any visible damage to the
surface of the coupons although the white tile seemed to take on a slight blue tint. Table 5-6
provides some additional detail about the operational factors for DeconGel as observed during
the use of this experimental setup/test stand with relatively small coupons. The information
below is applicable only to the experimental scenario using small concrete coupons.
Table 5-6. Operational Factors of DeconGel
Parameter
Description/Information
Decontamination
rate
Coating preparation: Provided ready for use.
Application: Two applications of 2 coats applied 2 h apart. Each coat included
approximately 0.75 L applied to 22 coupons (total of 0.5 m2) taking approximately 11
min. This corresponds to an overall application rate of 2-4 m2/hour and a DeconGel
volumetric use rate of 1.5 L/m2 for each coat.
Drying time: overnight
Removal time: Brick: 1.5 m2/h, tile: 3 m2/h, granite: 2 m2/h
Estimated volume used per application of 22 coupons (0.5 m2) included 1.5 L
DeconGel.
Applicability to
irregular surfaces
Application to more irregular surfaces than what is encountered during this evaluation
would not seem to be much of a problem as a paint brush can reach most types of
surfaces as long as the operator can access the surfaces. DeconGel cures into a rather
rigid coating that was conducive for use on the surfaces made from brick, tile, granite,
mortar, and grout coupons used during this evaluation. As can be observed from the
decontamination rates above, DeconGel was most difficult to remove from the brick,
second most difficult to remove from the granite and easily removed from the tile.
Skilled labor
requirement
After a brief training session to explain the procedures, most able-bodied people
would successfully perform both the application and removal procedures.
Utilities
requirement
None was required in this case because a paint brush application was used.
According to the vendor, DeconGel can be applied using a paint sprayer.
Extent of portability
With the exception of extreme cold, which would prevent the application of
DeconGel (which is water-based), its portability seems limitless.
Shelf life of media
Shelf life is advertised as one year.
Secondary waste
management
Solid waste production: -200 g/m2 for application of two coats
Surface damage
Not visible to the eye, removed only loose particles that were seen to be stuck to the
coating. For the mortar surface, many particles were attached to dried coating.
Cost
Cost is $40/L for DeconGel which corresponds to approximately $76/m2 for each
coat if used in a similar way as used during this evaluation.
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5.2.2 RRII
A number of operational factors were documented by the technician who performed the testing
with RRII. The application of RRII was described in Section 3.2.2 and included use of plastic
spray bottles. These application and removal times are applicable only to the experimental
scenario involving these rather small coupons. According to the manufacturer, if RRII was
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, but a
visible residue was left remaining after rinse and removal of the RRII. Table 5-7 provides some
additional detail about the operational factors for RRII as observed using this experimental
setup/test stand with relatively small coupons.
Table 5-7. Operational Factors of RRII
Parameter
Description/Information

Technology Preparation: RRII is provided ready to use. The solutions (Formula 1
and Formula 2) were transferred into spray bottles and applied.
Decontamination
rate
Application: Using this experimental setup, the initial application of RRII Formula 1
to the 22 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. In all, the application and removal steps
took 25 minutes in addition to the two 30 minutes dwell times for RRII. Aside from
the dwell times, this corresponds to a rate of approximately 1.2 m2/hour for RRII.
Estimated volumes used per application 22 coupons (0.2 m2) included 400 mL RRII
Formula 1, 350 mL RRII Formula 2, and 300 mL of the rinse solution.
Applicability to
irregular surfaces
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.
Skilled labor
requirement
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.
Utilities
requirement
Electricity for the wet vacuum. Larger surfaces may require more complex equipment
such as spray or foam application requiring additional utilities.
Extent of portability
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.
Secondary waste
management
Approximately 1 L of liquid was applied per 22 coupons used during this evaluation.
That volume corresponds to a waste generation rate of approximately 2 L/m2
depending on how much of the solutions absorb to the surfaces. Waste solution had
to be neutralized from acidic pH before disposal.
Surface damage
All surfaces appeared to have a thin layer of residual RRII Formula II left after the
final rinse and removal. Initially it appeared as if the coupon just had not fully dried
after rinse, but close inspection revealed the residual material.
Cost
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 projects costs are in the approximate range of $33-$55/m2.
RRII, Rad-Release II
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5.2.3 Super Gel
A number of operational factors were documented by the technician who performed the testing
with SuperGel. The application of SuperGel was described in Section 3.2.3 and once fully
mixed, SuperGel had the look of cooked oatmeal. In addition, the mixture was very "slippery"
and tended to slide off plastic tools. SuperGel caused no visible damage to the surface of the
coupons. Table 5-8 provides some additional detail about the operational factors for SuperGel as
observed during the use of this experimental setup/test stand with relatively small coupons.
Table 5-8. Operational Factors of SuperGel	
Parameter
Description/Information

Technology Preparation: 15 minutes to measure and mix powder with water.
SG is able to be used for several days after mixing as long as SG is kept moist
by covering the mixture as it will dry out if left exposed to air for several days.
Decontamination
rate
Application: SG was applied with a four inch paint brush to each coupon in
approximately 30 seconds (3 m2/h). After a 90 minute dwell time, SG was
removed with a wet vacuum and the surface was wiped with a paper towel at a
rate of approximately 30 seconds per coupon (3 m2/hour). Aside from the wait
time (which is independent of the surface area), the application and removal
rate was approximately 1 m2/hour. Estimated volumes used per 22 coupons
included 2 L of SG. Overall that volume corresponds to a loading of
approximately 4 L/m2.
Applicability to
irregular surfaces
Application to irregular surfaces may be problematic as SG could slide off
jagged edges and be difficult to apply to hard to reach locations. During use
on the rough split face granite, a small amount of SG could be seen remaining
in the crevices after vacuum removal. SuperGel tended to slide off the tile
surface unless the application layer was kept very thin (less than 4 millimeters)
Skilled labor
requirement
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.
Utilities
requirement
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.
Extent of portability
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 SG at scale applicable to an urban contamination
(area of city blocks or square miles).
Secondary waste
management
2 L of SG was applied for 22 coupons during this evaluation. That volume
corresponds to a waste generation rate of approximately 4 L/m2. SG was
collected entirely by the wet vacuum.
Surface damage
All surfaces appeared undamaged, but some residual SuperGel particles were
observed.
Cost
Material cost is approximately $0.30/L. This cost corresponds to $1.50/m2-
$3.00 if used in a way similar to the process used during this evaluation. Labor
costs were not calculated.
SG, SuperGel
5.2.4 LH-21
The application of LH-21 was described in Section 3.2.4 and included use of a plastic spray
bottle. According to the manufacturer, if LH-21 was 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. LH-21 did not
24

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EPA/600/R-16/150
June 2016
cause any visible damage to the surface of the coupons. Table 5-9 provides some additional
detail about the operational factors for LH-21 as observed using this experimental setup/test
stand with relatively small coupons.
Table 5-9. Operational Factors of LH-21	
Parameter
Description/Information

Technology Preparation: Five minutes to dilute LH-21 1:1 with water and
transferred into spray bottle for application.
Decontamination
rate
Application: Initial application of LH-21 to the 22 coupons took 40 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 60 minute dwell time, the LH-21 was
reapplied and scrubbed into the coupons followed by rinsing and vacuuming
which took approximately 20 seconds per coupon. In all, the application and
removal steps took 10 minutes in addition to the 60 minute dwell time. Aside
from the dwell time, this corresponds to a decontamination rate of
approximately 1 m2/hr for LH-21.
Estimated volumes used per application of 22 coupons (0.5 m2) included 1.6 L
LH-21 and 375 mL of rinse water.
Applicability to
irregular surfaces
Application to irregular surfaces would not seem to be problematic, LH-21 is
easily sprayed into hard to reach locations. Irregular surfaces may pose a
problem for vacuum removal.
Skilled labor
requirement
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.
Utilities
requirement
Electricity for the wet vacuum. Larger surfaces may require more complex
equipment such as spray or foam application requiring additional utilities.
Extent of portability
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 LH-21 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.
Secondary waste
management
Approximately 2 L of liquid was applied per 22 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.
Surface damage
No visible damage to the surface was observed.
Cost
$1.50/L for the LH-21. Corresponds to approximately $4/m2for LH-21.
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6.0 References
1.	U.S. Environmental Protection Agency, Technical Report for the Demonstration of Wide
Area Radiological Decontamination and Mitigation Technologies for Building Structures and
Vehicles, Cincinnati, Ohio: U.S. Environmental Protection Agency, March 2016.
EPA/600/R-16/019
2.	American National Standards Institute. Calibration and Use of Germanium Spectrometers for
the Measurement of Gamma Emission Rates of Radionuclides, ANSI N42.14-1999. New
York: IEEE (Rev. 2004).
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Appendix I
27

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Efficacy by Surface and Technology
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Brick_Mortar	TiIe_Grout	GraniteJVIortar
¦ Rad-Release II ¦ SuperGel ¦DeconGel
Figure A-l. Efficacy by surface and technology.
Mortar
I Intek LH-21
Efficacy by Technology and Surface

100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
Rad-Release II	SuperGel	DeconGel
¦ Brick Mortar ¦Tile Grout ¦ Granite Mortar ¦ Mortar
Figure A-2. Efficacy by technology and surface.
28

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vvEPA
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
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