&EPA
EPA/600/R-08/100 I September 2008 I www.epa.gov/ord
United States
Environmental Protection
Agency
Isotron Corp.
Orion™
Radiological Decontamination
Strippable Coating
TECHNOLOGY EVALUATION REPORT
Office of Research and Development
National Homeland Security Research Center
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EPA/600/R-08/100 I September 2008 I www.epa.gov/ord
Technology Evaluation Report
Isotron Corp.
Orion™
Radiological Decontamination
Strippable Coating
By
Ryan R. James and Zachary J. Willenberg
Battelle
505 King Avenue
Columbus, OH 43201
Robert V. Fox
Idaho National Laboratory
P.O. Box 1625
MS 2208
Idaho Falls, ID 83415
John Drake
Task Order Project Officer
National Homeland Security Research Center
Office of Research and Development
U.S. Environmental Protection Agency
26 Martin Luther King Drive
Cincinnati, OH 45268
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Notice
The U.S. Environmental Protection Agency (EPA), through its Office of Research and
Development's National Homeland Security Research Center, funded and managed
this technology evaluation through a Blanket Purchase Agreement under General
Services Administration contract number GS23F0011L-3 with Battelle. This report has
been peer and administratively reviewed and has been approved for publication as an
EPA document. Mention of trade names or commercial products does not constitute
endorsement or recommendation for use of a specific product.
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Preface
The U.S. Environmental Protection Agency (EPA) is charged
by Congress with protecting the nation's air, water, and
land resources. Under a mandate of national environmental
laws, the Agency strives to formulate and implement actions
leading to a compatible balance between human activities
and the ability of natural systems to support and nurture
life. To meet this mandate, EPA's Office of Research and
Development (ORD) provides data and science support that
can be used to solve environmental problems, to build the
scientific knowledge base needed to manage our ecological
resources wisely, to understand how pollutants affect our
health, and to prevent or reduce environmental risks.
In September 2002, EPA announced the formation of the
National Homeland Security Research Center (NHSRC). The
NHSRC is part of ORD; it manages, coordinates, supports,
and conducts a variety of research and technical assistance
efforts. These efforts are designed to provide appropriate,
affordable, effective, and validated technologies and methods
for addressing risks posed by chemical, biological, and
radiological terrorist attacks. Research focuses on enhancing
our ability to detect, contain, and decontaminate in the event
of such attacks.
NHSRC's team of world renowned scientists and
engineers is dedicated to understanding the terrorist threat,
communicating the risks, and mitigating the results of
attacks. Guided by the roadmap set forth in EPA's Strategic
Plan for Homeland Security, NHSRC ensures rapid
production and distribution of security-related products.
The NHSRC has created the Technology Testing and
Evaluation Program (TTEP) in an effort to provide reliable
information regarding the performance of homeland security
related technologies. TTEP provides independent, quality
assured performance information that is useful to decision
makers in purchasing or applying the tested technologies.
TTEP provides potential users with unbiased, third-
party information that can supplement vendor-provided
information. Stakeholder involvement ensures that user
needs and perspectives are incorporated into the test design
so that useful performance information is produced for each
of the tested technologies. The technology categories of
interest include detection and monitoring, water treatment, air
purification, decontamination, and computer modeling tools
for use by those responsible for protecting buildings, drinking
water supplies, and infrastructure, and for decontaminating
structures and the outdoor environment. In addition,
environmental persistence information is important for
containment and decontamination decisions.
The evaluation reported herein was conducted by Battelle as
part of the TTEP program. Information on NHSRC and TTEP
can be found at http://www.epa.gov/nhsrc.
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Acknowledgments
The authors wish to acknowledge the support of Dr. Howard Hall of the Lawrence
Livermore National Laboratory and Drs. Emily Snyder and Sang Don Lee of the U.S.
EPA National Homeland Security Research Center for their review of the test/QA plan
and this report.
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Contents
Notice iv
Preface v
Acknowledgments vi
Abbreviations/Acronyms ix
Executive Summary x
1.0 Introduction 1
2.0 Technology Description 3
3.0 Experimental Details 5
3.1 Experimental Preparation 5
3.1.1 Concrete Coupons 5
3.1.2 Coupon Contamination 5
3.1.3 Measurement of Activity on Coupon Surface 5
3.1.4 Surface Construction Using Test Stand 5
3.2 Evaluation of the Orion™ SC 6
3.2.1 Application of the Orion™ SC 6
3.2.2 Progressive Decontamination Efficacy With Each Application of Orion™ SC 6
4.0 Quality Assurance/Quality Control 7
4.1 Intrinsic Germanium Detector 7
4.2 Audits 8
4.2.1 Performance Evaluation Audit 8
4.2.2 Technical Systems Audit 8
4.2.3 Data Quality Audit 8
4.3 QA/QC Reporting 8
5.0 Evaluation Results 9
5.1 Decontamination Efficacy 9
5.1.1 7-Day Decontamination Efficacy Results 9
5.1.2 30-Day Decontamination Efficacy Results 10
5.1.3 Comparison of 7-Day and 30-Day Decontamination Efficacy 10
5.1.4 Progressive Decontamination Efficacy With Each Application of Orion™ SC 11
5.2 Deployment and Operational Factors 12
5.2.1 Description of Application 12
5.2.2 Description of Removal 13
5.2.3 Miscellaneous Operational Information and Data 13
6.0 Performance Summary 15
6.1 Decontamination Efficacy 15
6.2 Deployment and Operational Factors 15
6.3 Conclusion 15
7.0 References 17
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Figures
Figure 2-1. Preparation, Application, and Removal of the Orion™ SC 3
Figure 3-1. Concrete Coupons and Test Stand With the Contaminated Coupons Labeled "V" for Vertical
and"H" for Horizontal 6
Figure 5-1. Orion™ SC After Application and After Drying Overnight 12
Figure 5-2. Orion™ SC Removal 13
Tables
Table 3-1. Characteristics of the Portland Cement Clinker 5
Table 4-1. Calibration Results - Difference (keV) FromTh-228 Calibration Energies 7
Table 4-2. NIST-Traceable Eu-152 Activity Standard Check 8
Table 5.1. 7-Day Decontamination Efficacy Results 9
Table 5-2. 30-Day Decontamination Efficacy Results 10
Table 5-3. Decontamination Efficacy With Each Application of Orion™ SC 11
Table 5-4. Operational Factors Gathered From the Evaluation 14
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Abbreviations/Acronyms
BQ Bequerel
Cs cesium
C centigrade
cm centimeters
D&D decontamination and decommissioning
DARPA Defense Advanced Research Projects Agency
DF decontamination factor
DHS U.S. Department of Homeland Security
DoD Department of Defense
EPA U.S. Environmental Protection Agency
Eu Europium
g gram
INL Idaho National Laboratory
keV kilo electron volts
kg kilogram
mg milligram
mL milliliter
L liter
m meter
uCi microcuries
NHSRC National Homeland Security Research Center
ORD Office of Research and Development
Orion™ SC Isotron Orion™ strippable coating
%R percent removal
PE Performance evaluation
psi pounds per square inch
QA quality assurance
QC quality control
QMP quality management plan
ROD radiological dispersion device
RML Radiological Measurement Laboratory
Th Thorium
TSA technical systems audit
TTEP Technology Testing and Evaluation Program
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Executive Summary
The U.S. Environmental Protection Agency's (EPA's)
National Homeland Security Research Center (NHSRC)
Technology Testing and Evaluation Program (TTEP) is
helping to protect human health and the environment
from adverse impacts resulting from acts of terror by
carrying out performance tests on homeland security
technologies. Under TTEP, Battelle recently evaluated
the performance of Orion™ strippable coating (Orion™
SC) from Isotron Corporation (Seattle, Washington). The
objective of evaluating the Orion™ SC was to test its
ability to remove radioactive cesium (Cs)-137 from the
surface of unpainted concrete.
The Orion™ SC contains affinity shifting and binding
chemistries that are designed to extract and bind Cs-137. The
Orion™ SC is applied as a paint. Following cure, the bound
cesium can be removed from the surface by peeling away the
Orion™ SC. Prior to the evaluation of the Orion™ SC,
15 cm X 15 cm unpainted concrete coupons were
contaminated with Cs-137 at a level of approximately 53
microcuries (uCi, measured by gamma spectroscopy),
and then several of these contaminated coupons were used
within horizontal and vertical surfaces constructed with a
total of 24 coupons.
Following manufacturer's recommendations, the
Orion™ SC was applied and removed three successive
times before the residual activity was measured. In addition,
an evaluation of the decontamination efficacy of the
Orion™ SC was performed both 7 and 30 days following
application of the contaminant to the coupons. Results
include the decontamination efficacies, a comparison of
the decontamination efficacy between the vertical and
horizontal surfaces, and a comparison between the 7-day
and 30-day results. Important deployment and operational
factors were also documented and reported. A summary of
the evaluation results for the Orion™ SC is presented below
for each performance parameter. Discussion of the observed
performance can be found in Section 5 of this report.
Decontamination Efficacy: The decontamination efficacy,
expressed as percent removal, %R, attained by the Orion™
SC was evaluated on separate concrete surfaces after 7 days
and 30 days following the contamination of the coupons.
Overall, the Orion™ SC decontaminated the concrete
coupons with an average %R of 76.2 ± 7.4. The %Rs from
the vertical and horizontal surfaces were determined to be not
significantly different from one another. In addition, the %Rs
between the 7-day and 30- day tests were also determined
to be not significantly different from one another. The only
factor that did seem to have a statistically significant impact
on the performance of the Orion™ SC was coupon placement
near the edge of the vertical surface. These coupons were
shown to be slightly less efficiently decontaminated than
those placed vertically among other coupons (i.e., not on
the edge). This difference was likely due to differences in
the application technique near the edge and not due to a
deficiency in the Orion™ SC. In each of the three Orion™
SC application and removal cycles, 72%-92% of the Cs-137
was removed during the first application cycle.
Deployment and Operational Factors: Following the
manufacturer's recommendations, the Orion™ SC was mixed
from two concentrates to make a coating the consistency
of wall paint. The Orion™ SC was applied to the surfaces
with an airless paint sprayer. The surfaces had an area of
l.lm2 and each application coat took less than one minute.
The objective was to attain a layer of paint-like coating
approximately 40 mils thick. Because coating thickness
was not measured, a qualitative guideline was followed.
The coating was applied thick enough to cover the surface,
but not so thick that the coating ran down the wall. Isotron
recommended that three coats be applied with a 5 minute
wait between each coat. Following application, the coating
dried overnight and was removed using a paint scraper. First,
coupon edges were scored. Scoring allowed the coating on
each coupon to be loosened before it was pulled off. In most
cases, the Orion™ SC coating was removed one coupon at a
time without much removal across the border (a distance of
approximately 0.3-0.7 cm) between coupons. The Orion™
SC removal rate was 1.6 m2 per hour, the rate of waste
generation (removed coating) was 0.5 kg/m2, and the volume
of the waste was, on average, 0.188 g/cm3. Cured Orion™
SC formed flat, flaky, skin-like pieces; the inelastic coating
tore easily.
This evaluation showed that the rate of decontamination
will depend primarily on the surface finish or texture of
the concrete. Large, smooth surfaces would permit faster
removal than smaller surfaces. In addition, rough or jagged
surfaces are likely to increase removal times because the
Orion™ SC might tear and come off in small pieces. A
limited evaluation of cross-contamination was performed and
the results confirmed that cross-contamination did occur to
a small extent. If there was any damage to the surface of the
concrete caused by the Orion™ SC, it was not visible to the
naked eye.
Conclusion: The Orion™ SC removed approximately
76% of the Cs-137 from unpainted concrete coupons placed
together to form concrete surfaces with both horizontal and
vertical orientations. The Orion™ SC worked equally well
in either orientation and after both 7 and 30 days following
the application of Cs-137 to the concrete coupons. The
removal rate of Orion™ SC will likely be dependent on the
characteristics of the surface being decontaminated as some
scraping is required for removal.
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1.0
Introduction
U.S. Environmental Protection Agency's (EPA's) National
Homeland Security Research Center (NHSRC) is helping
to protect human health and the environment from adverse
effects resulting from intentional acts of terror. With an
emphasis on decontamination and consequence management,
water infrastructure protection, and threat and consequence
assessment, NHSRC is working to develop tools and
information that will help detect the intentional introduction
of chemical or biological contaminants in build-ings or
water systems, the containment of these contaminants, the
decontamination of buildings and/or water systems, and the
disposal of material resulting from cleanups.
NHSRC's 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 the 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 evaluated technologies.
Under TTEP, Battelle recently evaluated the performance
of the Isotron Orion™ strippable coating (Orion™ SC)
in decontaminating the radioactive isotope Cs-137 from
concrete. This evaluation was conducted according to a
peer-reviewed test/QA plan1 that was developed according to
the requirements of the quality management plan (QMP) for
TTEP2 The following performance characteristics of Orion™
SC were evaluated:
• Decontamination efficacy defined as the extent of
radionuclide removal following application and removal|
of the Orion™ SC.
• 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; the possibility of cross-
contamination; and the cost of using the Orion™ SC.
This evaluation took place from December 10, 2007 until
January 21, 2008. All of the experimental work took place
at U.S. Department of Energy's Idaho National Laboratory
(INL). This report describes the quantitative results and
qualitative observations gathered during this evaluation of
the Orion™ SC. Quality Assurance oversight of this
evaluation was provided by Battelle, INL, and EPA. Under
the direction of the Battelle QA Manager, INL QA staff
conducted a technical systems audit (TSA) during the
evaluation. The Battelle QA Manager conducted a data
quality audit of all evaluation data.
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2.0
Technology Description
This technology evaluation report provides results on the
performance of the Orion™ SC under laboratory conditions.
Following is a description of the Orion™ SC, based on
unverified information provided by Isotron Corp. (Seattle,
Washington).
Isotron's Orion™ SC is a non-toxic, strippable coating
designed for the decontamination of cesium and cobalt
radionuclides, and intended for use following a radiological
dispersion device (RDD) event in an urban environment,
as well as other radiological decontamination applications
(such as decontamination and decommissioning (D&D)
activities at DOE and commercial nuclear facilities). The
Orion™ SC extracts contaminants from the subsurface of
porous materials through a binding agent and physically
through encapsulation of the radionuclides into the cured
coating. Orion™ SC is sold as a two-part concentrate that
requires mixing with water. Consequently, the Orion™ SC is
applied like paint; therefore, a brush, roller, or sprayer are all
application options. The target thickness during application
is 40 mils. Following application, the coating requires
approximately 6 hours to cure prior to removal. Peeling the
coating removes contamination from the substrate surface,
producing a low volume, solid waste.
The left photograph in Figure 2-1 illustrates preparation of
the paint-like formulation from concentrates and water. The
middle photo shows application of the Orion™ SC to the
concrete coupon surfaces. The coating is then removed, as
shown to the right.
Figure 2-1. Preparation (left), Application (middle), and Removal of the Orion™ SC (right)
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3.0
Experimental Details
3.1 Experimental Preparation
3.1.1 Concrete Coupons
The concrete coupons were prepared from a single batch
of concrete made from Type II Portland cement3. Table
3-1 lists data provided by the ready-mix vendor about the
cement clinker used in the concrete mix. The ASTM C1503
requirement for Type II Portland cement specifies that
tricalcium aluminate 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. The
maximum allowable tricalcium aluminum content for Type
I is 15%, so the cement used during this evaluation met the
specifications for both Type I and II Portland cements.
Table 3-1. Characteristics of the Portland Cement
Clinker
Cement Constituent
Tricalcium Silicate
Dicalcium Silicate
Tricalcium Aluminate
Tetracalcium Aluminoferrite
Minor constituents
Percent of Mixture
57.6
21.1
4.5
8.7
8.1
The wet concrete was poured into 0.9 meter (m) square
plywood forms with the surface exposed. The concrete
surface was "floated" to get the smaller aggregate and cement
paste to rise to the top and then cured for 21 days. Following
curing, the squares were cut to the desired size with a laser
guided rock saw. For this evaluation, the "floated" surface
of the concrete coupons was used. The coupons were
approximately 4 centimeters (cm) thick, 15 cm square,
and had a surface finish that was consistent across all the
coupons and representative of exterior concrete commonly
found in urban environments in the U. S. as shown by INL
under a U.S. Department of Defense, Defense Advanced
Research Projects Agency (DARPA) and U.S. Department of
Homeland Security (DHS) project4.
3.1.2 Coupon Contamination
Each contaminated coupon was spiked with 2.5
milliliters (mL) of unbuffered, slightly acidic aqueous
solution containing 137 milligrams (mg)/liter (L) Cs-137
corresponding to an activity level of approximately 53 uCi
over the 225 cm2 surface. Application of the cesium in
an aqueous solution was justified because even if cesium
were dispersed in a particle form following an ROD event,
morning dew or rainfall would likely occur before the
surfaces could be decontaminated. In addition, the ability
to apply liquids homogeneously across the surface of the
concrete coupons greatly exceeds that for particles.
The liquid spike was delivered to each coupon using an
aerosolization technique developed by INL under the
DARPA/DHS project4 and described in detail in the test/QA
plan1. The aerosol delivery device was constructed of two
syringes. The first syringe had the plunger removed and a
nitrogen gas line was attached to the rear of the syringe. The
second syringe contained the contaminant spiking solution
and was equipped with a 27 gauge needle which penetrated
through the plastic housing near the tip of the first syringe.
Nitrogen gas was turned on at a flow of approximately
1-2 liters per minute creating a turbulent flow through the
first syringe. The liquid spike in the second syringe was
introduced and became nebulized by the turbulent gas 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. Coupon edges were taped and
sealed with epoxy to ensure that the contaminant was applied
only to the surfaces. Contaminant was sprayed to the edges of
the coupons.
3.1.3 Measurement of Activity on Coupon Surface
Measurement of gamma radiation from the surface of
concrete coupons was used to quantify contamination levels
before and after application of the strippable coating. These
measurements were made using one of three identical
intrinsic, high purity germanium detectors following
contamination and after application of the Orion™ SC. After
being placed into the detector, each coupon was measured
until the average activity level of Cs-137 from the surface
stabilized to a relative standard deviation of less than 2%.
Gamma-ray spectra, acquired from Cs-137 spiked coupons,
were analyzed using the INL Radiological Measurement
Laboratory (RML) data acquisition and spectral analysis
programs. Radionuclide activities on coupons were calculated
based on the efficiency, emission probability, and half-life
values. Decay corrections were made based on reference
time and date, and the duration of the counting period.
Full RML gamma counting QA/Quality Control (QC), as
described in the test/QA plan, was employed and certified
results were provided.
3.1.4 Surface Construction Using Test Stand
To evaluate the decontamination technologies on vertical
surfaces (simulating walls) as well as horizontal surfaces
(simulating sidewalks and drives), a test stand was fabricated
that held four rows of six concrete coupons to create
surfaces that were approximately 90 cm wide X 60 cm deep
(horizontal) or tall (vertical). Six of the 24 coupons used
to construct each surface were contaminated with Cs-137.
Figure 3-1 shows a picture of several concrete coupons
and a test stand loaded with the concrete coupons. After
the coupons were contaminated with Cs-137, some were
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Figure 3-1. Concrete Coupons (left) and Test Stand With the Contaminated Coupons
Labeled "V" for Vertical and "H" for Horizontal (right)
allowed to age for 7 days and some for 30 days prior to their
placement in the test stand for application and removal of
the Orion™ SC. The two different time frames were used to
evaluate the effectiveness of decontamination technologies
within one week of a radiological incident and also within
one month. Within the surfaces on the test stand, the six
contaminated coupons were arranged so there was one
coupon on each side edge, one on the top edge, and several
not on an edge.
Figure 3-1 shows the pattern of contaminated coupons on
each surface. The coupon codes indicate the orientation
of each coupon (H for horizontal and V for vertical) as
well as the location within the surface (position A-E).
The top surfaces of the coupons were not labeled during
the evaluation.
3.2 Evaluation of the Orion™ SC
3.2.1 Application of the Orion™ SC
The decontamination process was begun 7 days (7-
day test) following the application of the Cs-137 to the
concrete coupons. However, because the vendor, Isotron,
recommends multiple applications and removals of the
Orion™ SC, three application and removal cycles were
completed before the final measurement of residual activity
was made. To summarize the timeline, the 7-day coupons
were contaminated on December 3 and then included in the
construction of the vertical and horizontal surfaces on the test
stand. The first application of the Orion™ SC was made to
the surfaces on December 10 and allowed to dry overnight.
The first removal of the Orion™ SC was performed on
December 11, the second application/removal cycle was
performed on December 11 and 12, and the final application/
removal cycle was performed on December 12 and 13.
Therefore, the final removal of the Orion™ SC was
performed 10 days following application of the Cs-137
to the coupons. In a similar way, the 30-day coupons
were contaminated on December 17 and the first of three
applications of the Orion™ SC was performed on January 16
and completed over the next several days. Following
the final removal of the Orion™ SC, the contaminated
coupons were removed from the surfaces and residual
activity was measured.
The temperature and relative humidity were recorded during
both the 7-day and 30-day tests. These conditions did not
vary significantly in the laboratory where the coupons were
stored and the evaluation was performed. Over the duration
of testing, the temperature was always within the range of
23-26°C and the relative humidity was always within the
range of 11-17%.
5.2.2 Progressive Decontamination Efficacy With Each
Application of Orion™ SC
The focus of this evaluation was determining the overall
decontamination efficacy of the Orion™ SC following
Isotron's recommended procedures. Those procedures called
for the Orion™ SC to be applied and removed three times
before measurement of the residual activity. However, as a
side experiment during the evaluation, a few coupons were
measured following each application and removal of Orion™
SC to determine the degree of decontamination that occurred
with each application and removal of the Orion™ SC. The
progressive decontamination efficacy was determined using
two and three coupons and for the 7- and 30-day tests,
respectively. Only two coupons were analyzed for the 7-day
test because of the limited availability of contaminated
coupons. The first 7-day coupon, labeled "HA" in Figure 3-1,
was removed from the surface and transported to the RML
for counting; the second 7-day coupon and all of the 30-day
coupons were contaminated as extras in case of accidental
breakage.These coupons were set in a horizontal orientation
to the side of the test stand and the Orion™ SC was applied
and removed as for the rest of the coupons on the test stand.
These coupons were transported to the RML for activity
measurement four times, once upon application of Cs-137
and once following each of three applications and removals
of Orion™ SC.
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4.0
Quality Assurance/Quality Control
QA/quality control (QC) procedures were performed in
accordance with the program QMP2 and the test/QA plan1 for
this evaluation.
4.1 Intrinsic Germanium Detector
Calibrations of intrinsic, high purity germanium detectors
were established using standardized procedures from
American National Standards Institute and the Institute of
Electrical and Electronics Engineers5. Detector energy was
calibrated using thorium (Th)-228 daughter gamma rays
at 238.6, 583.2, 860.6, 1620.7, and 2614.5 kilo electron
volts (keV). This calibration was performed weekly and
documented by the RML. Table 4-1 shows the results of the
calibrations by giving the difference between the known
energy levels and those measured following calibration. The
energies were compared to the previous 30 calibrations. The
operator was alerted if the results exceeded three standard
deviations of the other calibration results. The calibrations
are shown for each of the three detectors used during
this evaluation. None of these calibrations exceeded that
threshold.
For each measurement of activity on each coupon, gamma
ray counting was continued until the activity level of Cs-137
on the surface had a relative standard deviation of less
than 2%. The final activity assigned to that coupon was a
compilation of information obtained from all components
of the electronic assemblage, which comprised the "gamma
counter," including the raw data and the spectral analysis
conducted by the spectroscopist using an INL data analysis
program. Final spectra and all data which comprised the
spectra were sent to a data analyst who independently
confirmed the "activity" number determined by the
spectroscopist. When both the spectroscopist and an expert
data analyst independently arrived at the same number, then
the data were certified. This entire process defines the full
gamma counting QA process for certified results.
The background activity of the concrete coupons was
determined by the analysis often arbitrarily selected coupons
from the stock of concrete coupons. The ambient activity
level of these coupons was measured for two hours and the
activity for all of the coupons was determined to be below
the minimum detectable level of 2X10~4 uCi. Because the
background activity was not detectable, and the detectable
level was more than 5,000 times lower than the post-
decontamination activity levels, no background subtraction
was required.
Throughout the evaluation, 12 contaminated coupons were
measured as duplicates. Four duplicate analyses each were
completed for three sample sets including coupons that had
been contaminated, coupons decontaminated during the
7-day test, and coupons decontaminated during the 30-day
test. Three of the duplicate samples showed no difference
from the original measurement, while the average percent
difference between the original and duplicate measurements
was 0.71%, within the acceptable difference of 3%.
Table 4-1. Calibration Results - Difference (keV) From Th-228 Calibration Energies
Calibration Energy Levels in keV
Date
11-6-2007
12-3-2007
12-11-2007
12-18-2007
1-15-2008
1-22-2008
Detector
1
4
5
1
4
1
4
1
4
1
4
1
4
Energy 1
238.632
-0.002
-0.004
-0.002
0.000
-0.006
-0.002
-0.004
-0.003
-0.003
-0.003
-0.004
-0.006
-0.003
Energy 2
583.191
0.008
0.022
0.007
0.002
0.022
0.008
0.014
0.012
0.013
0.012
0.018
0.022
0.011
Energy 3
860.564
-0.004
-0.119
-0.006
-0.025
-0.076
-0.040
-0.041
-0.026
-0.063
-0.042
-0.069
-0.022
-0.032
Energy 4
1620.735
-0.206
-0.028
-0.193
0.028
-0.170
-0.108
-0.194
-0.273
-0.135
-0.190
-0.211
-0.390
-0.169
Energy 5
2614.511
0.022
0.013
0.019
-0.001
0.034
0.011
0.025
0.028
0.018
0.022
0.024
0.055
0.021
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Table 4-2. NIST-Traceable Eu-152 Activity Standard Check
Date
11-11-2007
11-13-2007
12-11-2007
1-15-2008
Detector
4
1
5
1
4
1
4
NISTActivity(BQ)
124,600
124,600
124,600
124,600
124,600
124,600
124,600
INLRML Result (BQ)
130,300
122,900
124,700
122,400
128,900
122,000
129,300
Difference
5%
1%
0%
2%
3%
2%
4%
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 NIST-traceable Eu-152 standard (in units of
Bequerel, BQ) and comparing it to the accepted NIST value.
Results within 7% of the NIST value are considered to be
within acceptable limits. The Eu-152 activity comparison
is a routine quality control activity performed by INL. For
the purposes of this evaluation, the calibration serves as the
performance evaluation (PE) audit that confirms the accuracy
of the calibration standards used for the instrumentation
critical to the results of our evaluation. Table 4-2 gives the
results of each of these audits for each detector that was used
during this evaluation. All results are within the acceptable
difference of 7%.
4.2.2 Technical Systems Audit
A technical systems audit was conducted during testing
at INL to ensure that the evaluation was performed in
accordance with the test/QA plan1 and the TTEP QMP2
As part of the audit, the actual evaluation procedures were
compared with those specified in the test/QA plan1. In
addition, the data acquisition and handling procedures were
reviewed. No significant adverse findings were noted in this
audit. The records concerning the TSA are stored indefinitely
with the Battelle Quality Assurance Manager.
One deviation from the test/QA plan occurred during this
evaluation. The contaminant application was done using
2.5 mL of solution rather than 0.25 mL in order to better
cover the concrete coupon.
4.2.3 Data Quality Audit
At least 10% of the data acquired during the evaluation were
audited. The Battelle Quality Assurance 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.
4.3 QA/QC Reporting
Each assessment and audit was documented in accordance
with the test/QA plan1 and the QMP.2 Once the assessment
report was prepared by the Battelle Quality Assurance
Manager, it was routed to the Test Coordinator and Battelle
TTEP Program Manager for review and approval. The
Battelle Quality Assurance Manager then distributed the final
assessment report to the EPA Quality Manager and Battelle
staff.
One test/QA plan deviation occurred during this evaluation.
Instead of a 0.25 mL volume of cesium spiking solution as
was stated in the test/QA plan, a 2.5 mL volume was used in
order to attain a more homogeneous coverage across each
coupon. The evaluation was not negatively impacted.
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5.0
Evaluation Results
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/Ao) X 100% and DF = A/Af
where Ao is the radiological activity from the surface of the
coupon before application of the Orion™ SC and Af is the
radiological activity from the surface of the coupon after
removal of the strippable coating. The DFs are reported in the
following data tables, but for the sake of brevity, the narrative
describing the results will focus on the %R.
The following sections describe the performance of the
Orion™ SC 7 and 30 days after contaminant application
and on horizontal and vertical surfaces. Throughout the
evaluation, Microsoft® Excel was used to perform paired
t-tests in order to determine if significant differences existed
within the data set. In all cases, the t-tests were two-tailed
and were conducted at the 95% confidence interval.
5.1.1 7-Day Decontamination Efficacy Results
Table 5-1 gives the %R and DF for the Orion™ SC after a
7-day time period between coupon contamination and use of
the Orion™ SC. The coupon codes indicate the orientation of
each coupon (H for horizontal and V for vertical) as well as
Table 5-1. 7-Day Decontamination Efficacy Results
the location within the surface (position A-E) as illustrated
in Figure 3-1. The target activity for each of the contaminated
coupons (pre-decontamination) was within the acceptable
range of 53 uCi ±5.3 uCi. The average (plus or minus
one standard deviation) of the contaminated coupons was
55.7 uCi ±1.3 uCi for the horizontal surface, 53.6 uCi ±
1.5 uCi for the vertical surface, and 54.5 uCi ±1.7 uCi
overall. There was a variability of 3% across all the coupons
on both surfaces.
Evaluating the Orion™ SC in the horizontal and the vertical
orientations was an important objective for this evaluation.
Because the Orion™ SC is applied as a liquid, the evaluation
sought to find out if the coating adhered adequately to the
wall to accomplish decontamination with similar efficacies
as in the horizontal orientation. Post-decontamination coupon
activities were significantly less than pre-decontamination
activities.
For the horizontal and vertical surfaces, the %Rs (defined in
Section 5.1) were 79.7 ± 4.1 and 77.5 ± 5.2, respectively.
These were determined to be not significantly different as
determined by paired t-test analysis (p=0.51), indicating
that the decontamination efficacy of the Orion™ SC in the
horizontal and vertical orientations was similar. The overall
average %R for the 7-day test was 78.6 ± 4.6.
The contaminated coupons were placed at various locations
across the surface and various paired t-tests were performed
Horizontal
Vertical
Overall
Coupon Code
HA
HB
HC
HD
HE
HF
Avg
SD
VA
VB
VC
VD
VE
VF
Avg
SD
Avg
SD
Pre-Decon Activity
uCi/ Coupon
55.6
56.0
55.9
57.5
53.4
55.6
55.7
1.3
55.6
54.8
52.4
51.9
54.5
52.5
53.6
1.5
54.6
1.7
Post-Decon Activity
uCi / Coupon %R
15.2
11.8
9.5
9.2
9.9
12.1
11.3
2.3
12.2
10.4
9.1
16.7
11.7
12.0
12.0
2.6
11.7
2.3
72.7
78.9
82.9
83.9
81.5
78.2
79.7
4.1
78.1
81.0
82.6
67.8
78.5
77.1
77.5
5.2
78.6
4.6
DF
3.7
4.7
5.9
6.2
5.4
4.6
5.1
0.9
4.6
5.3
5.8
3.1
4.7
4.4
4.6
0.9
4.9
0.9
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to see whether or not location on the surface impacted the
decontamination efficacy. Within the 7-day coupons, those on
the edge (horizontally and/or vertically) of the surfaces were
compared with those not on the edges to see if significant
differences existed. During the 7-day test, no such differences
were identified, therefore, the Orion™ SC performed equally
on the vertical and horizontal surfaces whether the coupons
were located on an edge or not.
5.1.2 30-Day Decontamination Efficacy Results
Table 5-2 gives the %R and DF for the Orion™ SC after a
30-day period between contaminant application and use of
the Orion™ SC. As with the 7-day results, the target activity
for each of the contaminated coupons (pre-decontamination)
was within the acceptable range of 53 uCi ±5.3 uCi. The
overall average (plus or minus one standard deviation)
of the contaminated coupons was 53.6 uCi ± 1.8 uCi for
the horizontal surface, 53.3 uCi ± 1.9 uCi for the vertical
surface, and 53.5 uCi ± 1.8 uCi across all the coupons in
both surfaces, a variability of 3%.
The post-decontamination coupon activities were
significantly less than the pre-decontamination activities.
For the horizontal and vertical surfaces respectively, the
%Rs (defined in Section 5.1) were 76.2 ± 11.2 and 71.5 ±
6.3. These were determined to be not significantly different
by a paired t-test analysis (p=0.50), indicating that the
decontamination efficacy of the Orion™ SC in the horizontal
and vertical orientations was similar. The overall average %R
for the 30-day test was 73.8 ± 9.0.
As with the 7-day coupons, the contaminated coupons
included on the surfaces were placed at various locations
across the surface and various paired t-tests were performed
to determine if location within the surface impacted the
decontamination efficacy. Within the 30-day coupons, those
on the edge of the surfaces were compared with those not
on the edges to see if significant differences existed. During
the 30-day test, the three coupons that were oriented
vertically on the edge (VA, VD, and VF) had an average %R
of 66.6 ±4.3 while the three that were placed vertically not
on the edge (i.e., they were surrounded by other coupons)
(VB, VC, and VE) had an average %R of 76.3 ± 3.3. A
paired t-test showed these two averages to be significantly
different from one another at the 95% confidence interval
(p=0.021). An experimental plan designed to explore this
issue would be required to determine what may have caused
this small difference.
5.1.3 Comparison of 7-Day and 30-Day
Decontamination Efficacy
Given there were no significant differences determined
between the horizontal and vertical surfaces during the 7-day
or 30-day tests, the overall average %Rs can be compared
to determine if the Orion™ SC performed differently during
the two sets of experiments. The overall average %Rs for
the 7-day and 30-day tests were 78.6 ± 4.6 and 73.8 ±
9.0, respectively, suggesting that the increased time of the
contaminant binding to the concrete surface caused a slightly
decreased %R. However, a paired t-test determined that
these two averages were not significantly different from
Table 5-2. 30-Day Decontamination Efficacy Results
Coupon Code
HA
HB
HC
HD
Horizontal
HE
HF
Avg
SD
VA
VB
VC
VD
Vertical
VE
VF
Avg
SD
Avg
Overall
SD
Pre-Decon Activity
uCi / Coupon
52.5
54.3
56.4
51.9
51.8
54.8
53.6
1.8
55.2
54.7
51.7
51.5
51.7
55.2
53.3
1.9
53.5
1.8
Post-Decon Activity
uCi / Coupon
12.4
10.6
25.6
8.0
12.2
8.5
12.9
6.5
20.1
14.9
10.8
14.7
11.8
19.5
15.3
3.8
14.1
5.2
%R
76.4
80.5
54.6
84.6
76.4
84.5
76.2
11.2
63.6
72.8
79.1
71.5
77.2
64.7
71.5
6.3
73.8
9.0
DF
4.2
5.1
2.2
6.5
4.2
6.5
4.8
1.6
2.7
3.7
4.8
3.5
4.4
2.8
3.7
0.8
4.2
1.4
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Table 5-3. Decontamination Efficacy With Each Application of Orion™ SC
Orion™ SC
Test Application3
Pre-decon
#1
#2
#3
7-Day
Pre-decon
#1
#2
#3
Pre-decon
#1
#2
#3
Pre-decon
#1
30-Day
#2
#3
Pre-decon
#1
#2
#3
Activity
|jCi / Coupon
55.6
21.9
17.1
15.2
61.8
13.1
9.68
8.61
56.5
22.9
17.4
15.1
55.0
29.2
22.0
19.4
54.1
19.3
13.4
11.3
Total %R
NAb
60.6
69.2
72.7
NA
78.8
84.3
86.1
NA
59.5
69.2
73.3
NA
46.9
60.0
64.7
NA
64.3
75.2
79.1
%R Each
Application
NA
60.6
8.6
3.4
NA
78.8
5.5
1.7
NA
59.5
9.7
4.1
NA
46.9
13.1
4.7
NA
64.3
10.9
3.9
% of Total
Removal
NA
83.4%
11.9%
4.7%
NA
91.6%
6.4%
2.0%
NA
81.2%
13.3%
5.5%
NA
72.5%
20.2%
7.3%
NA
81.3%
13.8%
4.9%
a For the 7-day test, one of the coupons was the "HA" coupon that was removed for counting, all the other coupons were not a part of either
surface, but were contaminated like the others and placed horizontally alongside the test stand. The Orion™ SC was applied as usual.
b Not applicable as this was the initial measurement of activity.
one another at the 95% confidence interval (p=0.12). This
difference is not significant because the standard deviations
of the post-decontamination activity measurements across
several coupons increased significantly compared with the
pre-decontamination measurement of activity across the
same coupons. This increase indicates the somewhat variable
efficacy of the Orion™ SC in removing Cs-137 from the
surface of the concrete.
In addition to the comparison of overall average, various
paired t-tests were performed, including data from both the
7-day and 30-day tests to allow observation of whether or
not location on the surface impacted the decontamination
efficacy. The increased number of data points improved
statistical power in determining significant differences in the
data. Thus, all of the vertical and horizontal coupons, edge
and non-edge, from both tests were compared to determine
if significant differences existed. Out of these analyses, one
t-test comparison generated a significant difference. The
comparison included the results from the 7-day and 30-day
vertical coupons on the edge of the surface versus the 7-day
and 30-day vertical coupons not on the edge of the surface.
Those groups of coupons had average %Rs of 70.5 ±
6.2 and 78.5 ± 3.4, respectively, which were determined
to be significantly different from one another at the 95%
confidence interval (p=0.013). This difference suggested that
over both testing time periods, the coupons on the edge of the
vertical surface were decontaminated slightly less effectively
than those not on the edge of the vertical surface, which is
consistent with the result determined during the 30-day test.
5.1.4 Progressive Decontamination Efficacy With Each
Application of Orion™ SC
As described previously, the use of the Orion™ SC
followed the procedures recommended by Isotron (i.e.,
three successive applications and removals). Therefore,
a few coupons were measured after each application/
removal cycle to determine the level of decontamination
with each cycle. Table 5-3 shows the results from each
measurement of activity starting with the initial measurement
prior to the first application and removal of Orion™ SC
through three successive applications and removals of the
Orion™ SC. Table 5-3 also shows the total %R (additive
across applications), the %R attributed to each successive
application, and the percent of total removal attributable to
each application cycle. For example, of the 72.7 %R that
was attained for the first 7-day coupon, 60.9% was attained
-------
with the first application. Overall, the first application
corresponded to 83.4% of the total removal from that coupon.
The results indicated that most of the decontamination
occurs with the first application and removal cycle of the
Orion™ SC. While only five coupons were tested in this
fashion, the results were consistent. The percent of total
removal during the first cycle of application and removal of
the Orion™ SC ranged from 72 to 92%, from 6% to 20% for
the second cycle, and from 2% to 7% for the third and final
cycle. An experimental design more focused on this aspect
of the Orion™ SC's performance would be required to draw
additional conclusions.
5.2 Deployment and Operational Factors
5.2.1 Description of Application
The Orion™ SC was provided as two concentrates called
"Part A" and "Part B." Part A (2,200 g) was combined with
Part B (550 g) along with 100 mL of water. The final product
was white and had a consistency similar to paint. Prior to
the application of the Orion™ SC, a Graco Magnum™
XR7 sprayer, with a Graco 417 tip obtained at a home
improvement store, was primed with the wet Orion™ SC
as directed by the manufacturer's instructions. The sprayer
was provided by Isotron Corp. for this evaluation. Any
commercially available, airless paint sprayer with similar
specifications could be used. The sprayer manufacturer's
operating instructions should be followed.
The Orion™ SC was applied to the concrete coupon surfaces.
There was no calibrated pressure indicator. The maximum
pressure of this sprayer was 3,000 pounds per square inch
(psi) and the spray pattern that produced an even, covering
coating with no significant runs occurred when the pressure
was adjusted to the maximum and then the knob turned back
approximately one-quarter of a turn.
The Orion™ SC was applied in three coats. We examined
each coat to see that it covered the vertical surface of
the concrete coupon but did not buildup and run. Spray
application to the horizontal and vertical surfaces took
approximately 1 minute. After the first and second coats, the
sprayer operator paused for approximately 5 minutes, then
added another coat. An average of 1.4 L of wet Orion™ SC
was applied with each application to the 1.1 m2 surfaces.
Figure 5-1 shows a picture of the Orion™ SC freshly applied
to the vertical surface and then again following the overnight
drying time. Note that the running of coating from a few
coupons had occurred.
Figure 5-1. Orion™ SC After Application (left) and After Drying Overnight (right)
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Figure 5-2. Orion™ SC Removal
5.2.2 Description of Removal
The removal of Orion™ SC was done following the
overnight drying, which hardened the Orion™ SC into a rigid
surface. The Orion™ SC was removed mostly one coupon at
a time using a paint scraper to score the edge of the coupon
and free the coating from the surface. Then the loose coating
was torn from the surface. Figure 5-2 shows the removal
process. The total amount of dried coating removed from the
surface was collected in a tared bag and weighed. The time
to remove the Orion™ SC from the two surfaces (totaling
1.1 m2) ranged from 30-52 minutes for an average rate of
removal of 1.6 mVhour. The ease of removal depended on the
thickness of the coating.
For example, during the first 30-day application and
removal, a much thinner coating had been applied because
too much water had inadvertently been added when mixing
the concentrates. Therefore, a thinner consistency and
thus, a thinner layer of coating was the result. This thin
application caused the dried coating to be brittle and flaky,
making the removal more labor intensive, thus taking longer
(52 minutes). However, as Table 5-2 shows, the change
in amount of water did not seem to negatively impact the
removal of Cs-137 from the surface.
The coating was removed from one coupon at a time, with
the coating breaking at the border of the coupons. The
technicians noted that had a large, flat surface been used
rather than a surface made of discrete coupons, a larger
scraper could have been used to remove larger pieces of
dried coating.
5.2.3 Miscellaneous Operational Information and Data
Table 5-4 includes important operational parameters such
as the time required to apply and remove the coating,
required skill level of the operator, portability of the
technology, estimated cost, required utilities, and cross-
contamination concerns.
Orion™ SC was applied to relatively small surfaces (1.1 m2)
that were built with concrete coupons. Therefore, some of
the information given in Table 5-4 could differ if the Orion™
SC was applied to larger surfaces or surfaces that were either
more smooth or more rough and jagged.
The amount of time required to apply the Orion™ SC
probably will not be the limiting rate step because use of a
paint sprayer is efficient. In addition, the paint sprayer can
be used on a wide variety of regularly or irregularly shaped
surfaces. The technicians observed that the rate of removal
of the cured coating will depend heavily on the surface
characteristics of the concrete.
For example, the Orion™ SC had to be removed one coupon
at a time because the cured coating tended to break at the
edges of the concrete coupons. Prior to the Orion™ SC being
removed, the edge needed to be scored and the removal
process started over again, rather than being a continuation of
a similar process on the same surface.
Therefore, the removal rate might be higher for larger,
continuous surfaces. Similarly, the removal rate might also
depend on the smoothness of the surfaces. The Orion™ SC
needed to be scraped from the surface of the concrete, so
the cured coating fractured at the edges of the coupons.
Removing the Orion™ SC from rough concrete would be
labor intensive because the coating comes off in small pieces.
One important aspect of the shelf-life of the Orion™ SC
was observed as part of this evaluation. The Orion™ SC
concentrates were shipped to INL from Isotron. At some
point during shipment, the concentrates froze and then
thawed by the time of arrival at INL. The freeze/thaw
cycle caused the Orion™ SC to solidify within the sprayer
pump and tubing, preventing its application to the surface.
Following that incident, Isotron shipped the Orion™ SC
using a qualified shipper to ensure that the Orion™ SC did
not freeze en route. Isotron recommends that Orion™ SC be
stored within a temperature range of 15.6-26.7°C.
Cross-contamination of radionuclides during application
and removal of Orion™ SC is an operational aspect that
was considered to a minimal extent during this evaluation.
As has been described, six coupons from each surface
had been contaminated prior to the construction of the
surfaces. The other coupons had not been contaminated
and, upon placement into the test stand, indicated extremely
low background levels of activity when measured with a
qualitative gamma counter. When all of the coupons were
removed from the test stand following the three application
-------
Table 5-4. Operational Factors Gathered From the Evaluation
Parameter
Factors affecting
decontamination rate
Applicability to irregular
surfaces
Skilled labor requirement
Utilities requirement
Extent of portability
Shelf life of media
Secondary waste
management
Surface damage
Cost
Description/Information
Coating Preparation: 10 minutes to mix concentrates and 20 minutes to prime pump.
Application: three 1-minute applications 5 minutes apart; equaling 13 minutes, for an average
of 1.4 L applied to 1.1 m2
Drying time: overnight
Removal rate: 1.6 m2/hour
Application to more irregular surfaces than those encountered during this evaluation would
not seem to be much of a problem because a sprayer is able to reach most types of surfaces;
however, removal from irregular surfaces might be more labor intensive. The technicians
observed that the Orion™ SC had to be removed coupon by coupon; therefore, if the coupons
were much larger, the removal might go more quickly. If the surface was rough, removal of the
Orion™ SC might become difficult because the cured coating would be likely to come off in
small pieces.
After a brief training session, and time to acclimate to using a paint sprayer, most able-bodied
people could successfully perform both the application and removal procedures.
A paint sprayer generally requires 110 volt power. However, the Orion™ SC can also be
applied with a roller or brush, eliminating the need for a separate power source.
With the exception of extreme cold, which would prevent the application of the water-based
Orion™ SC, its portability seems limitless.
The Orion™ SC concentrates were shipped to INL from Isotron. The concentrates froze at
some point during the shipment and thawed by the time of arrival at INL. The freeze/thaw cycle
caused the Orion™ SC to solidify within the sprayer pump and tubing. Isotron sent another
batch of concentrates, using a qualified shipper to ensure that the coating did not freeze. The
recommended storage temperature for Orion™ SC is 15.6-26.7°C.
Solid waste production: -0.5 kg/m2
Solid waste volume: -0.188 g/cm3
The coating was usually removed from concrete coupons one coupon at a time. However, if
there had been larger continuous surfaces, the pieces might have been larger because the
cured coating usually tore at the border of the coupons. Cured Orion™ SC formed flat, flaky,
skin-like pieces; the coating was not elastic, so it tended to tear easily.
No damage was visible to the eye; some loose particles could be seen stuck to the coating.
$46.23/1 corresponding to $58.84/m2 for one application. Isotron suggests three applications,
equaling $176.51/m2, not including the cost of a paint sprayer.
and removal cycles of Orion™ SC for both the 7-day and
30-day tests, the non-contaminated coupons indicated a
activity level (again using the qualitative gamma counter)
that was higher than background. While the study of
cross-contamination was not a focus of the evaluation, the
activity from a few of the non-contaminated coupons was
quantitatively measured. Over the 7-day and 30-day tests,
the residual activity of ten non-contaminated coupons
ranged from 0.00028 uCi-0.0042 uCi and had an average
activity of 0.0014 uCi ± 0.0014 uCi. As this was not a focus
of the evaluation, the proper controls were not in place to
thoroughly investigate the observed cross-contamination. The
possibility exists that cross-contamination occurred during
the construction of the surfaces on the test stand and might be
independent of Orion™ SC.
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6.0
Performance Summary
Summary results from evaluation of the Orion™ SC are
presented below for each performance parameter evaluated.
Discussion of the observed performance can be found in
Section 5 of this report.
6.1 Decontamination Efficacy
The Orion™ SC was evaluated by contaminating concrete
coupons that were approximately 4 cm thick and 15 cm
square with Cs-137 at a level of 53 uCi (measured by gamma
spectroscopy) and placing them at edge and non-edge
locations within a vertical and horizontal surface built on a
test stand containing 24 of these coupons. The Orion™ SC
was applied and removed three times before the residual
activity was measured.
The decontamination efficacy attained by the Orion™ SC
was evaluated on separate test stands after both 7 days and
30 days following the contamination of the coupons. Overall,
the Orion™ SC decontaminated the concrete coupons with
an average %R of 76.2 ± 7.4. The %Rs from the vertical and
horizontal surfaces were determined to be not significantly
different from one another. In addition, the %Rs between
the 7-day and 30- day tests were also determined to be not
significantly different from one another.
The only factor that did seem to have a statistically
significant impact on the performance of the Orion™ SC
was if the coupons were placed on the edge of the vertical
surface. These coupons were shown to be slightly less
efficiently decontaminated than those that were placed
vertically among other coupons (i.e., not on the edge). The
cause of this difference is likely due to differences in the
application technique near the edge as opposed to being
due to a deficiency in the Orion™ SC. In addition, a brief
investigation of how much of the Cs-137 removal takes place
upon successive Orion™ SC applications suggested that
72% - 92% of the removed Cs-137 is removed during the
first application and removal of the Orion™ SC.
6.2 Deployment and Operational Factors
The Orion™ SC was mixed from two concentrates to make
a coating with the consistency similar to wall paint. Then,
the coating was applied to the surfaces with an airless paint
sprayer. The surfaces used during this evaluation had an area
of 1.1 m2 and each coat took less than one minute to apply.
The objective of application was to attain a layer of "paint-
like" coating thick enough to cover by visual inspection,
but not too thick that the coating ran down the wall. Isotron
recommended that three coats be applied with a 5 minute
wait between each coat. Following application, the coating
was allowed to dry overnight and then removed using a paint
scraper to score the edge of the coupons and then loosen
the coating from each coupon before the loosened coating
could be pulled off. In most cases the Orion™ SC coating
was removed one coupon at a time without much removal
across the border between coupons. The Orion™ SC removal
rate was 1.6 m2 per hour, the rate of waste generation was
0.5 kg/m2, and the volume of the waste was, on average,
0.188 g/cm3. Cured Orion™ SC formed flat, flaky, skin-
like pieces; the coating was not elastic, so it tended to tear
easily. The results of this evaluation suggest that the rate of
decontamination will depend heavily on the surface of the
concrete. Large, smooth surfaces would likely be conducive
to rather fast rates of removal, while smaller surfaces (as
in this evaluation) make for more labor intensive removal.
In addition, rough or jagged surfaces are likely to increase
removal times as the Orion™ SC may tear or come off in
small pieces. Any damage to the surface of the concrete
caused by the Orion™ SC was not visible to the naked eye.
6.3 Conclusion
The Orion™ SC removed approximately 76% of the
Cs-137 from the unpainted concrete coupons placed
together to form concrete surfaces with both horizontal and
vertical orientations. The Orion™ SC worked the same in
either orientation as well as at 7 or 30 days following the
application of the Cs-137 to the concrete coupons. The
removal rate of Orion™ SC depends on the characteristics of
the surface being decontaminated because some scraping is
required for removal.
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7.0
References
1. Test/Q A Plan, The Performance of Selected Radiological Decontamination Processes on Urban Substrates,
Version 1.0, Battelle, Columbus, OH, Sept. 2007.
2. Quality Management Plan for the Technology Testing and Evaluation Program, Version 2.0, Battelle,
Columbus, Ohio, January 2006.
3. ASTM Standard C 150-07, 2007, "Standard Specification for Portland Cement," ASTM International, West
Conshohocken, PA, www.astm.org.
4. Radionuclide Detection and Decontamination Program, Broad Agency Announcement 03-013, U.S.
Department of Defense (DoD) Defense Advanced Research Projects Agency (DARPA) and the U.S.
Department of Homeland Security, classified program.
5. 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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