tPA 600/R-11/Q14 | May 2011 ] www.epa.gov/ord
United States
Environmental Protection
Agency
Empire Abrasive Blast
N'Vac for Radiological
Decontamination
TECHNOLOGY EVALUATION REPORT
Office of Research and Development
National Homeland Security Research Center

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EPA 600-R-11-014
May 2011
Technology Evaluation Report
Empire Abrasive Blast N'Vac for
Radiological Decontamination
United States Environmental Protection Agency
Cincinnati, OH 45268

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Disclaimer
The U.S. Environmental Protection Agency (EPA), through its Office of Research and
Development's National Homeland Security Research Center, funded and managed this
technology evaluation through a Blanket Purchase Agreement under General Services
Administration contract number GS23F0011L-3 with Battelle. This report has been peer and
administratively reviewed and has been approved for publication as an EPA document. Mention
of trade names or commercial products does not constitute endorsement or recommendation for
use of a specific product.
Questions concerning this document or its application should be addressed to:
John Drake
National Homeland Security Research Center
Office of Research and Development
U.S. Environmental Protection Agency
26 West Martin Luther King Dr.
Cincinnati, OH 45268
513-569-7164
drake.john@epa.gov
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Foreword
The Environmental Protection Agency (EPA) holds responsibilities associated with homeland
security events: EPA is the primary federal agency responsible for decontamination following a
chemical, biological, and/or radiological (CBR) attack. The National Homeland Security
Research Center (NHSRC) was established to conduct research and deliver scientific products
that improve the capability of the Agency to carry out these responsibilities.
An important goal of NHSRC's research is to develop and deliver information on
decontamination methods and technologies to clean up CBR contamination. When directing
such a recovery operation, EPA and other stakeholders must identify and implement
decontamination technologies that are appropriate for the given situation. The NHSRC has
created the Technology Testing and Evaluation Program (TTEP) in an effort to provide reliable
information regarding the performance of homeland security related technologies. TTEP
provides independent, quality assured performance information that is useful to decision makers
in purchasing or applying the tested technologies. TTEP provides potential users with unbiased,
third-party information that can supplement vendor-provided information. Stakeholder
involvement ensures that user needs and perspectives are incorporated into the test design so that
useful performance information is produced for each of the tested technologies. The technology
categories of interest include detection and monitoring, water treatment, air purification,
decontamination, and computer modeling tools for use by those responsible for protecting
buildings, drinking water supplies and infrastructure, and for decontaminating structures and the
outdoor environment. Additionally, environmental persistence information is also important for
containment and decontamination decisions.
NHSRC is pleased to make this publication available to assist the response community to prepare
for and recover from disasters involving CBR contamination. This research is intended to move
EPA one step closer to achieving its homeland security goals and its overall mission of
protecting human health and the environment while providing sustainable solutions to our
environmental problems.
Jonathan G. Herrmann, Director
National Homeland Security Research Center
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Acknowledgments
Contributions of the following individuals and organizations to the development of this document are
gratefully acknowledged.
United States Environmental Protection Agency (EPA)
John Drake
Emily Snyder
Sang Don Lee
Lukas Oudejans
David Musick
Kathy Hall
Eletha Brady-Roberts
Jim Mitchell
University of Tennessee
Howard Hall
United States Department of Energy's Idaho National Laboratories
Battelle Memorial Institute
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Contents
Disclaimer	ii
Foreword	iii
Acknowledgments	iv
Abbreviations/Acronyms	vii
Executive Summary	viii
1.0 Introduction	1
2.0 Technology Description	3
3.0 Experimental Details	5
3.1	Experiment Preparation	5
3.1.1	Concrete Coupons	5
3.1.2	Coupon Contamination	6
3.1.3	Measurement of Activity on Coupon Surface	7
3.1.4	Surface Construction Using Test Stand	7
3.2	Evaluation Procedures	8
4.0 Quality Assurance/Quality Control	10
4.1	Intrinsic Germanium Detector	10
4.2	Audits	11
4.2.1	Performance Evaluation Audit	11
4.2.2	Technical Systems Audit	12
4.2.3	Data Quality Audit	12
4.3	QA/QC Reporting	12
5.0 Evaluation Results	13
5.1	Decontamination Efficacy	13
5.2	Deployment and Operational Factors	14
6.0 Performance Summary	17
6.1	Decontamination Efficacy	17
6.2	Deployment and Operational Factors	17
7.0 References	19
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Figures
Figure 2-1. Blast N' Vac as assembled for testing (left). Closeup of Blast N' Vac
vacuum head (right)	4
Figure 2-2. Blast N' Vac abrasive grit reservoir, HEPA filter, and collection drum	4
Figure 3-1. Demonstration of contaminant application technique	6
Figure 3-2. Containment tent: outer view (left) and inner view with test stand containing
contaminated coupons (right)	7
Figure 3-3. Operator applying Blast N' Vac to concrete coupon	9
Figure 5-1. Test coupon surfaces before (left) and after (right) treatment with the
Blast N'Vac	14
Tables
Table 3-1. Characteristics of Portland Cement Clinker Used to Make Concrete Coupons	5
Table 4-1. Calibration Results - Difference from Th-228 Calibration Energies	10
Table 4-2. NIST-Traceable Eu-152 Activity Standard Check	11
Table 5-1. Decontamination Efficacy Results	14
Table 5-2. Operational Factors Gathered from the Evaluation	16
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Abbreviations/Acronyms
ANSI	American National Standards Institute
ASTM	American Society for Testing and Materials
BQ	Becquerel
Cs	cesium
cfm	cubic feet per minute
cm	centimeters
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
ft	feet
HEPA	High Efficiency Particle Air
IEEE	Institute of Electrical and Electronics Engineers
INL	Idaho National Laboratory
keV	kilo electron volts
mg	milligram
mL	milliliter
L	liter
m	meter
m2	square meter
|iCi	microCuries
NHSRC	National Homeland Security Research Center
NIST	National Institute of Standards and Technology
ORD	Office of Research and Development
%R	percent removal
PE	performance evaluation
psi	pounds per square inch
QA	quality assurance
QC	quality control
QMP	quality management plan
RDD	radiological dispersion device
RML	Radiological Measurement Laboratory
RSD	relative standard deviation
TSA	technical systems audit
TTEP	Technology Testing and Evaluation Program
Th	thorium
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Executive Summary
The U.S. Environmental Protection Agency's (EPA) National Homeland Security Research
Center (NHSRC) is helping to protect human health and the environment from adverse impacts
resulting from acts of terror by carrying out performance tests on homeland security
technologies. Through its Technology Testing and Evaluation Program (TTEP), NHSRC
evaluated the performance of the Empire Abrasive Blast N' Vac (hereafter referred to as the Blast
N'Vac) and its ability to remove radioactive cesium (Cs)-137 from the surface of unpainted
concrete.
Experimental Procedures. The Blast N'Vac is a heavy duty abrasive grit blasting technology
that removes bound Cs from a surface by blasting away the concrete surface. Eight 15 centimeter
(cm) x 15 cm unpainted concrete coupons were contaminated with approximately 1 microCurie
(|iCi) of Cs-137 per coupon and allowed to age for seven days. The amount of contamination
deposited on each coupon was measured using gamma spectroscopy. The eight contaminated
coupons were placed in a test stand (along with one uncontaminated blank coupon) that was
designed to hold nine concrete coupons in a vertical orientation to simulate the wall of a
building. Each coupon was treated with the Blast N'Vac, and the decontamination efficacy was
determined by calculating both a decontamination factor (DF) and percent removal (%R).
Important deployment and operational factors were also documented and reported.
Results. The decontamination efficacy attained by the Blast N'Vac was evaluated for each
individual concrete coupon used during the evaluation. When the decontamination efficacy
metrics (DF and %R) of the eight contaminated coupons were averaged together, the average
%R for the Blast N'Vac was 97 ± 2% the average DF was 58 ± 52. Hypothesis testing was
performed to determine if there were significant differences among the %R values determined
for the coupons in each row (top, middle, and bottom) of the test stand. No differences were
found.
Following the manufacturer's recommendations, the Blast N'Vac was used with size 24
aluminum oxide abrasive grit. The rate at which the Blast N'Vac was used to decontaminate a
vertical surface was approximately 2.7 square meters (m2) per hour, with significant visual
surface destruction and some secondary waste. The texture of the concrete surface is not relevant
to the efficacy of the Blast N'Vac and similar blasting technologies. Battelle observed that,
because of the aggressiveness with which the abrasive grit removes concrete surfaces,
irregularities within the surface would not impact the effectiveness of the technology. The Blast
N'Vac required a source of compressed air that provided at least 400 cubic feet per minute (cfm)
of air flow at a pressure of 120 pounds per square inch (psi). An Ingersoll-Rand 75902 diesel-
powered air compressor was the only source of power required for the operation of the Blast
N'Vac. Such a large air compressor is not a common piece of equipment. Therefore, the size and
availability of the compressor required may limit the locations where the Blast N'Vac can be
used.

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A very limited evaluation of cross-contamination was performed. During an actual
decontamination of a vertical surface, the higher elevation surfaces would likely be
decontaminated first, possibly exposing the lower elevation surfaces to secondary contamination.
To simulate an actual scenario, one uncontaminated coupon was placed in the bottom row of the
test stand and decontaminated using the Blast N'Vac in the same way as the other coupons.
Following decontamination using the Blast N'Vac, this uncontaminated coupon did not exhibit
measurable activity, suggesting that cross contamination was minimal. It should be noted that
very small amounts of blasting abrasive grit (individual grains) were found throughout the
containment tent and there was some abrasive grit that collected at the base of the test stand.
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1.0 Introduction
The U.S. Environmental Protection
Agency's (EPA) National Homeland
Security Research Center (NHSRC) is
helping to protect human health and the
environment from adverse effects
resulting from acts of terror. NHSRC is
emphasizing decontamination and
consequence management, water
infrastructure protection, and threat and
consequence assessment. In doing so,
NHRSC is working to develop tools and
information that will improve the ability
of operational personnel to detect the
intentional introduction of chemical,
biological, or radiological contaminants
on or into buildings or water systems, to
contain or mitigate these contaminants,
to decontaminate affected buildings
and/or water systems, and to dispose of
contaminated materials resulting from
clean-ups.
NHSRC, through its Technology Testing
and Evaluation Program (TTEP), works
in partnership with recognized testing
organizations; stakeholder groups
consisting of buyers, vendor
organizations, and permitters; and
through the participation of individual
technology developers in carrying out
performance tests on homeland security
technologies. The program evaluates the
performance of homeland security
technologies by developing evaluation
plans that are responsive to the needs of
stakeholders, conducting tests, collecting
and analyzing data, and preparing peer-
reviewed reports. All evaluations are
conducted in accordance with rigorous
quality assurance (QA) protocols to
ensure that data of known and high
quality are generated and that the results
are defensible. TTEP provides high-
quality information that is useful to
decision makers in purchasing or
applying the evaluated technologies and
in planning clean-up operations. TTEP
provides potential users with unbiased,
third-party information that can
supplement 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, NHSRC recently
evaluated the performance of the Empire
Abrasive Blast N'Vac (Langhorne, PA;
hereafter referred to as the Blast N' Vac)
in removing radioactive isotope Cs-137
from concrete. A peer-reviewed test/QA
plan was developed according to the
requirements of the quality management
plan (QMP) for TTEP. The evaluation
generated the following performance
information:
• Decontamination efficacy, defined as
the extent of radionuclide removal
following use of the Blast N' Vac,
and the possibility of cross-
contamination.
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• Deployment and operational factors,
including the approximate rate of
surface area decontamination,
applicability to irregular surfaces,
skilled labor requirement, utility
requirements, portability, secondary
waste management, and technology
cost.
This evaluation took place from August
11, 2009 until October 13, 2009. All of
the experimental work took place in a
radiological contamination area at the
U.S. Department of Energy's Idaho
National Laboratory (INL). This report
describes the quantitative results and
qualitative observations gathered during
this evaluation of the Blast N' Vac. The
contractor, Battelle, and EPA were
responsible for QA oversight. The
Battelle QA Manager conducted both a
technical systems audit (TSA) and a data
quality audit of the evaluation data.
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2.0 Technology Description
The following description of the Blast
N' Vac is based on information provided
by the vendor and was not verified
during this evaluation.
Blast N'Vac is a heavy duty abrasive grit
blasting technology that also collects the
spent abrasive grit by means of a
blasting head surrounded with a vacuum
collection shroud. During this
evaluation, the Blast N'Vac was used
with size 24 aluminum oxide abrasive
grit. The Blast N' Vac was powered
entirely by compressed air. An Ingersoll-
Rand 75902 diesel-powered air
compressor provided approximately 400
cubic feet per minute (cfm) of
compressed air at approximately 120
pounds per square inch (psi). The Blast
N' Vac is plumbed to provide not only an
adequate amount of compressed air to
perform the abrasive grit blasting but
also adequate suction to perform the
abrasive grit recovery. The air
compressor was not provided by Empire
Abrasive, but is considered a required
utility for operation of the technology. In
addition, while not tested as part of this
evaluation, the Blast N'Vac came
equipped with blasting heads shaped
specifically for work in corners.
Figure 2-1 shows the Blast N' Vac
blasting gun used during this evaluation.
The photograph on the right clearly
shows the inner blasting head and the
vacuum shroud surrounding the blasting
head. Figure 2-2 shows (from left to
right) the abrasive grit reservoir, the high
efficiency particle air (HEPA) filter, and
the abrasive grit collection drum situated
on a skid. The Blast N' Vac can also be
equipped to recycle abrasive grit
continuously, but that feature was not
used during this evaluation in order to
minimize the amount of equipment at
risk of becoming contaminated with
radiological material. Therefore, the
abrasive grit was blasted and collected
for disposal in the collection drum. All
components in Figure 2-2 were
successfully protected from
contamination and were returned
following the evaluation.
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Figure 2-1. Blast N'Vac as assembled for testing (left). Close-up of Blast N'Vac
vacuum head (right).
Figure 2-2. Blast N'Vac abrasive grit reservoir, HE PA filter, and collection drum.
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3.0 Experimental Details
3.1 Experiment Preparation
3.1.1 Concrete Coupons
The concrete coupons were prepared
from a single batch of concrete made
from Type II Portland cement. The
ready-mix company (Burns Brothers
Redi-Mix, Idaho Falls, ID) that supplied
the concrete for this evaluation provided
the data which describe the cement
clinker used in the concrete mix. For
Type II Portland cement, the American
Society for Testing and Materials
(ASTM) Standard C 150-71 specifies
that tricalcium aluminate account for
less than 8% of the overall cement
clinker (by weight). The cement clinker
used for the concrete coupons was 4.5%
tricalcium aluminate (Table 3-1). For
Type I Portland cement the tricalcium
aluminate content should be less than
15%. Because Type I and II Portland
cements differ only in tricalcium
aluminate content, the cement used
during this evaluation meets the
specifications for both Type I and II
Portland cements.
Table 3-1. Characteristics of Portland Cement Clinker
	Used to Make Concrete Coupons	
	Cement Constituent	Percent of Mixture
Tricalcium Silicate	57.6
Dicalcium Silicate	21.1
Tricalcium Aluminate	4.5
Tetracalcium Aluminoferrite	8.7
Minor Constituents	8.1
The wet concrete was poured into 0.9
meter (m) square plywood forms with
the exposed surface "floated" to allow
the smaller aggregate and cement paste
to float to the top, and the concrete was
then cured for 21 days. Following
curing, the squares were cut to the
desired size with a laser-guided rock
saw. For this evaluation, the "floated"
surface of the concrete coupons was
used. The coupons were approximately
4 centimeters (cm) thick, 15 cm x 15 cm
square, and had a surface finish that was
consistent across all the coupons. The
concrete was representative of exterior
concrete commonly found in urban
environments in the United States as
shown by INL under a previous project
sponsored by the U.S. Department of
Defense (DOD), Defense Advanced
Research Projects Agency (DARPA) and
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U.S. Department of Homeland Security
(DHS).2
3.1.2 Coupon Contamination
Eight coupons were contaminated by
spiking individually with 2.5 milliliters
(mL) of aqueous solution that contained
0.26 milligrams (mg)/liter (L) Cs-137 as
a solution of cesium chloride,
corresponding to an activity level of
approximately 1 microCurie (juCi) over
the 225 cm2 surface. Application of the
Cs in an aqueous solution was justified
because even if Cs were dispersed in a
particle form following a radiological
dispersion device (RDD) or "dirty
bomb" event, morning dew or rainfall
would likely occur before the surfaces
could be decontaminated. In addition,
from an experimental standpoint, it is
much easier to apply liquids, rather than
dry particles, homogeneously across the
surface of the concrete coupons. The
liquid spike was delivered to each
coupon using an aerosolization
technique developed by INL (under a
DARPA/DHS project2) and described in
detail in the test/QA plan, and then
allowed to age for seven days.
The aerosol delivery device was
constructed of two syringes. The plunger
and needle were removed from the first
syringe and discarded. Then, a
compressed air line was attached to the
rear of the syringe. The second syringe
contained the contaminant solution and
was equipped with a 27 gauge needle,
which penetrated through the plastic
housing near the tip of the first syringe.
Compressed air flowing at a rate of
approximately 1 - 2 L per minute created
a turbulent flow through the first
syringe. When the contaminant solution
in the second syringe was introduced,
the solution became nebulized by the
turbulent air flow. A fine aerosol was
ejected from the tip of the first syringe,
creating a controlled and uniform spray
of fine liquid droplets onto the coupon
surface. The contaminant spray was
applied all the way to the edges of the
coupon, which were taped (after having
previously been sealed with polyester
resin) to ensure that the contaminant was
applied only to the surfaces of the
coupons. The photographs in Figure 3-1
show this procedure being performed
using a nonradioactive, nonhazardous
aqueous dye to demonstrate that the 2.5
mL of contaminant solution is
effectively distributed across the surface
of the coupon.
Figure 3-1. Demonstration of contaminant application technique.
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3.1.3 Measurement of Activity on
Coupon Surface
Gamma radiation from the surface of
each concrete coupon was measured to
quantify contamination levels both
before and after evaluati on of the Blast
N' Vac. These measurements were made
using an intrinsic, high purity
germanium detector (Canberra LEGe
Model GL 2825R/S, Meriden, CT).
After being placed in the detector, each
coupon was measured until the average
activity level of Cs-137 from the surface
stabilized to a relative standard deviation
of less than 2%. Gamma-ray spectra
acquired from Cs-137 contaminated
coupons were analyzed using INL
Radiological Measurement Laboratory
(RML) data acquisition and spectral
analysis programs (PCGAP, Idaho
National Engineering and Environmental
Laboratory, Idaho Falls, ID;
INEEL/EXT-2000-00908;
http://www.inl.gov/technicalpublications
/Documents/3318133.pdf). Radionuclide
activities on coupons were calculated
based on efficiency, emission probability
and half-life values. Decay corrections
were made based on the date and the
duration of the counting period. Full
RML gamma counting QA/quality
control (QC), as described in the test/QA
plan, was employed and certified results
were provided.
3.1.4 Surface Construction Using Test
Stand
To evaluate the decontamination
technologies on vertical surfaces
(simulating walls), a stainless steel test
stand was fabricated that held three rows
of three concrete coupons. A test stand,
approximately 9 feet (ft) x 9 ft, was
erected within a containment tent. The
concrete coupons were placed into
holders so their surfaces extended just
beyond the surface of the stainless steel
face of the test stand. Eight of the nine
coupons placed in the test stand were
contaminated with Cs-137, which has a
half-life of 30 years. One
uncontaminated coupon was placed in
the bottom row of the test stand and
decontaminated using the Blast N' Vac in
the same way as the other coupons. This
coupon was placed there to observe
possible secondary contamination
caused by the decontamination higher on
the wall. Figure 3-2 shows the
containment tent and the test stand
loaded with the concrete coupons.
Figure 3-2. Containment tent: outer view (left) and inner view with test stand
containing contaminated coupons (right).
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3.2 Evaluation Procedures
The containment tent consisted of two
rooms. One room contained the test
stand to hold the contaminated coupons
and the other room (the shorter part of
the tent as shown in Figure 3-2) held the
collection drum. The abrasive grit hoses
(both blasting and vacuum) connected to
the blasting head in the room with the
test stand through a small opening in the
tent wall between the two rooms. The
abrasive grit reservoir and air
compressor were located outside the
containment tent. The positive pressure
blasting hose was connected directly to
the blasting head through a small
opening in the outer tent wall, through
the smaller room, and also through a
small opening in the tent wall between
the two rooms. The vacuum line was
connected first to the collection drum
and then to the collection shroud
surrounding the blasting head, through
the same openings in the tent. Each of
the tent openings was taped closed
around the hoses. Figure 3-3 shows the
smaller diameter blasting hose and the
larger diameter vacuum hose connecting
to the blasting head as the operator
applies the Blast N' Vac to a concrete
coupon.
The nine concrete coupons in the test
stand were blasted with the Blast N'Vac
starting with the top row and working
from left to right, then proceeding to the
middle and bottom rows. The coupons
were blasted in this manner to simulate
an approach that would likely be taken
in an actual decontamination event,
where higher wall surfaces would be
decontaminated first because of the
possibility of secondary contamination
lower on the wall.
The flow of abrasive grit was controlled
by a trigger on the blasting head; the
vacuum flow was controlled by an on/off
valve near the abrasive grit reservoir.
Therefore, the vacuum ran during the
entire evaluation and the abrasive grit
flow was easily turned on and off
between coupons. Each coupon was
blasted for approximately 30 seconds.
However, the operator made certain he
had covered the entire surface before
progressing to the next coupon, so the
actual times for eight out of nine
coupons ranged from 22 to 35 seconds.
One coupon had taken 80 seconds
because of periodic diminished flow of
abrasive grit. The pressure conditions
during blasting were 66 psi on the
blaster and 50 psi for the vacuum (as
measured on the gauges near the
abrasive grit reservoir). The temperature
and relative humidity were recorded
before and after the approximately one
hour test. These conditions did not vary
significantly in the room where the
evaluation was performed. Over the
duration of testing, the temperature was
steady at 19.8 °C and the relative
humidity was 36%.
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Figure 3-3. Operator applying Blast N'Vac to concrete coupon,
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4.0 Quality Assurance/Quality Control
QA/ QC procedures were performed in
accordance with the program QMP and
the test/QA plan for this evaluation.
4.1 Intrinsic Germanium Detector
The germanium detector was calibrated
once each week. The calibration was
performed in accordance with
standardized procedures from the
American National Standards Institute
(ANSI) and the Institute of Electrical
and Electronics Engineers (IEEE).3 In
brief, detector energy was calibrated
using thorium (Th)-228 daughter gamma
rays at 238.6, 583.2, 860.6, 1620.7, and
2614.5 kilo electron volts (keV). This
calibration was performed three times
throughout the evaluation and
documented by the RML. Table 4-1
gives the difference between the known
energy levels and those measured
following calibration. The energies were
compared to the previous 30 calibrations
to confirm that the results were within
three standard deviations of the previous
calibration results. All the calibrations
fell within this requirement.
Table 4-1. Calibration Results - Difference from Th-228 Calibration Energies
	Calibration Energy Levels (keV)	
Energy 1 Energy 2 Energy 3 Energy 4 Energy 5
Date	238.632 583.191 860.564 1620.735 2614.533
8-25-2009	-0.005	0.014	-0.031 -0.199 0.031
9-21-2009	-0.003	0.009	-0.040 -0.125 0.015
10-13-2009	-0.003	0.008	-0.011 -0.180 0.020
Gamma ray counting was continued on
each coupon until the activity level of
Cs-137 on the surface had a relative
standard deviation (RSD) of less than
2%. This RSD occurred within the initial
1 hour of counting for all the coupons
measured during this evaluation. The
final activity assigned to each coupon
was a compilation of information
obtained from all components of the
electronic assemblage that comprise the
"gamma counter," including the raw data
and the spectral analysis described in
Section 3.1.3. Final spectra and all data
that comprise the spectra were sent to a
data analyst who independently
confirmed the "activity" number arrived
at by the spectroscopist. When both the
spectroscopist and an expert data analyst
independently arrived at the same value
the data were considered certified. This
process defines the full gamma counting
QA process for certified results.
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The background activity of the concrete
coupons was determined by analyzing
nine arbitrarily selected coupons from
the stock of concrete coupons used for
this evaluation. The ambient activity
level of these coupons was measured for
at least two hours. No activity was
detected above the minimum detectable
level of 2xl0"4 |iCi on these coupons.
Because the background activity was not
detectable (and the detectable level was
more than 150 times lower than the post-
decontamination activity levels), no
background subtraction was required.
Throughout the evaluation, a second
measurement was taken on 10 coupons
in order to provide duplicate
measurements to evaluate the
repeatability of the instrument. Half of
the duplicate measurements were
performed after contamination prior to
application of the decontamination
technology and half were performed
after decontamination. Five of the
duplicate pairs showed no difference in
activity levels between the two
measurements; the other five duplicate
pairs had a difference of 2% between the
two measurements, within the acceptable
difference of 5%.
4.2 Audits
4.2.1 Performance Evaluation Audit
RML performed regular checks of the
accuracy of the Th-228 daughter
calibration standards (during the time
when the detector was in use) by
measuring the activity of a National
Institute of Standards and Technology
(NIST)-traceable europium (Eu)-152
standard (in units of Becquerel, BQ) and
comparing to the accepted NIST value.
Results within 7% of the NIST value are
considered to be within acceptable
limits. TheEu-152 activity comparison
is a routine QC activity performed by
INL, but for the purposes of this
evaluation the activity comparison
serves as the performance evaluation
(PE) audit, an audit that confirms the
accuracy of the calibration standards
used for the instrumentation critical to
the results of an evaluation. Table 4-2
gives the results of each of the audits
applicable to the duration of the
evaluation. All results are below the
acceptable difference of 7%.
Table 4-2. NIST-Traceable Eu-152 Activity Standard Check	
Relative
NIST Activity INL RML Percent
Date	(BQ)	Result (BQ)	Difference
8-18-200	9	124,600	122,400	2%
9-10-200	9	124,600	122,600	2%
10-12-200	9	124,600	122,300	2%
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4.2.2	Technical Systems Audit
A TSA was conducted during testing at
INL to ensure that the evaluation was
performed in accordance with the
test/QA plan and the TTEP QMP. As
part of the audit, the actual evaluation
procedures were compared with those
specified in the test/QA plan and the
data acquisition and handling procedures
were reviewed. No significant adverse
findings were noted in this audit. The
records concerning the TSA are stored
indefinitely with the Battelle QA
Manager.
4.2.3	Data Quality Audit
The Battelle QA Manager verified all of
the raw data acquired during the
evaluation and transcribed into
spreadsheets for use in the final report.
The data were traced from the initial raw
data collection, through reduction and
statistical analysis, to final reporting, to
ensure the integrity of the reported
results.
4.3 QA/QC Reporting
Each assessment and audit was
documented in accordance with the
test/QA plan and the QMP. The Battelle
QA Manager prepared the draft
assessment report and sent it to the Test
Coordinator and Battelle TTEP Program
Manager for review and approval. The
Battelle QA Manager then sent the final
assessment report to the EPA QA
Manager and Battelle staff.
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5.0 Evaluation Results
5.1 Decontamination Efficacy
The decontamination efficacy of the
Blast N' Vac was measured for
contaminated coupons in terms of
percent removal (%R) and
decontamination factor (DF). Both of
these measurements provide a means of
%R = (1-Af/Ao) x
where A0 is the radiological activity
from the surface of the coupon before
application of the Blast N' Vac and Af is
radiological activity from the surface of
the coupon after treatment. While the
DFs are reported in Table 5-1, the
narrative describing the results focuses
on the %R.
Table 5-1 gives the %R and DF for the
Blast N'Vac. All coupons were oriented
vertically. The target activity for each of
the contaminated coupons (pre-
decontamination) was within the
acceptable range of 1 |iCi ± 0.5 |iCi. The
overall average (plus or minus one
standard deviation) of the contaminated
coupons was 1.17 |iCi ± 0.04 |iCi, a
variability of 3%. The post-
decontamination coupon activities were
less than the pre-decontamination
activities showing an overall reduction
in activity. The %R (calculated as
described above) averaged 97% ± 2%
and the DF averaged 58 ± 52. Overall,
the %R ranged from 92% to 99% and the
representing the extent of
decontamination accomplished by a
technology. The %R gives the extent as
a percent relative to the activity and the
DF is the ratio of the initial activity to
the final activity or the factor by which
the activity was decreased. These terms
are defined by the following equations:
100% and DF = A0/Af
DF ranged from 12 to 178. The coupon
with the DF of 178 was observed to have
exhibited a relatively high DF as the rest
of the coupons had DFs that were
substantially lower. The very high DF
was caused by the extremely low post-
decontamination activity for that
coupon. It is not clear why the coupon
was decontaminated more extensively
than the others.
Paired t-tests were performed to
determine whether location (top, middle,
or bottom) on the test stand affected the
decontamination efficacy. No significant
difference between any of the rows was
found. The bottom middle coupon was
not contaminated to test the possibility
of cross-contamination. Activity of the
uncontaminated coupon was measured
after the Blast N' Vac had been applied
to all nine coupons. No activity was
detected on that coupon, suggesting that
cross-contamination due to the
application of the Blast N' Vac was
minimal.
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Table 5-1. Decontamination Efficacy Results
Coupon
Location in
Test Stand
Pre-Decon Activity
pCi / Coupon
Post-Decon Activity
nCi / Coupon
%R
DF
Top left
1.19
0.007
99
178
Top middle
1.19
0.026
98
46
Top right
1.15
0.028
98
41
Center left
1.14
0.094
92
12
Center middle
1.19
0.015
99
82
Center right
1.24
0.033
97
38
Bottom left
1.12
0.028
98
40
Bottom right
1.14
0.042
96
27
Average	1.17	0.034	97	58
Std. Dev	0.04	0.026	2	52
5.2 Deployment and Operational
Factors
A number of operational factors were
documented by the Blast N' Vac
operator. One of the factors was damage
to the surface of the concrete coupons.
Figure 5-1 shows photographs of a
coupon before and after blasting with the
Blast N' Vac. The surface of the coupon
at the right has been removed by the
Blast N' Vac and the aggregate layer of
concrete has been exposed. This is
evidenced by the large pieces of gravel
and sand that are visible. Because of the
extensive surface removal, the
effectiveness of the Blast N'Vac will
have to be weighed against the amount
of surface damage caused by the
decontamination technology.

* * * - »'¦

	. -
Figure 5-1. Test coupon surfaces before (left) and after (right) treatment with the
Blast N'Vac.
Another important factor to consider is
the personal protection of the technology
operators. During this evaluation, the
radiological control technicians required
the operators to wear full anti-
contamination personal protective
equipment that included a full face
respirator with supplied air. This level
of personal protection was required by
the INL RCTs because of the likelihood
of airborne radiological contamination
due to the act of blasting. However,
each situation will need to be considered
independently by local RCTs to
determine the proper level of personal
protection.
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Table 5-2 summarizes qualitative and
quantitative practical information gained
by the operator during the evaluation of
the Blast N' Vac. All of the operational
information was gathered during use of
Blast N'Vac on the concrete coupons
inserted into the test stand. Some of the
information given in Table 5-2 could
differ if the Blast N' Vac were applied to
a larger surface or surfaces made up of
different types of concrete.
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Table 5-2. Operational Factors Gathered from the Evaluation
Parameter
Description/Information
Decontamination
rate
Technology Preparation: Upon initial receipt, it took 1.5 days to get the components
assembled and the abrasive grit valve to function properly. Initially, we provided
approximately 250 cfm of compressed air, however that flow rate did not allow the
proper function of the abrasive grit valve. Once we provided approximately 400 cfm
of compressed air at 120 psi the valve began to function well.
Application: Approximately 30 seconds per concrete coupon for most coupons during
this evaluation corresponds to an application rate of 2.7 m2/hour; less or more time
per coupon may result in different levels of radiological decontamination.
Applicability to
irregular surfaces
Irregular surfaces will not be a problem for the Blast N'Vac as the abrasive grit
blasting is an aggressive decontamination technique, thus removing the surface of the
concrete and making the operation of the Blast N'Vac independent of the surface
characteristics of the concrete. In addition, while coupon configurations other than a
flat square were not tested as part of this evaluation, the Blast N'Vac came equipped
with blasting heads shaped for work in corners and was designed to maintain the
ability to recover the abrasive grit following blasting.
Skilled labor
requirement
Adequate training would likely require approximately one hour. In addition to the
assembly and operation of the Blast N'Vac, topics would need to include precautions
unique to pressurized blasting, the theory of operation, and troubleshooting.
The operator experienced a significant level of exertion as he completed the
evaluation. The weight of the Blast N'Vac, in combination with the additional weight
and awkwardness of the attached blasting and vacuum hoses, increased the level of
effort required to use the Blast N'Vac. Depending on what row of the test stand is
being used, the operator was required to bend over, stand on the floor, or stand on a
ladder. These factors will exclude some people from operating the Blast N'Vac.
However, most people who are used to performing physical labor should not have
any problem operating the unit.
Utilities required
400 cfm compressed air at 120 psi is the sole utility requirement.
Extent of portability
The limiting factors of portability for the Blast N'Vac will include the availability of
400 cfm compressed air (longer hoses may require higher flow/pressure air and
vacuum). In addition, the skid containing the abrasive reservoir and HEP A filter is
approximately 3 ft by 8 ft and weighs several hundred pounds. Therefore, it is a
factor that would have to be considered to allow for portability.
Amount of spent
blasting media
Following blasting of nine coupons, approximately 20 pounds of abrasive grit was
used and approximately 5 pounds of concrete waste was collected.
Secondary waste
management
An estimated 95% of the abrasive grit was collected by the vacuum. There was very
little dust visible during the evaluation. However, very small amounts of blasting
abrasive grit (individual grains) were found throughout the containment tent
including at the base of the test stand. This abrasive was vacuumed up at the close of
the evaluation. The radiological control technicians overseeing the evaluation
determined that there was no secondary-contamination due to this wide distribution of
small amounts of abrasive grit. The activity of the grit and dust collected by the
vacuum or vacuum filter was not measured quantitatively. However, given the
effectiveness of the Blast N'Vac, presumably the waste had significant activity levels.
Surface damage
Surface removed and aggregate exposed. See description and photograph in text.
Cost
As evaluated, the price of the Blast N'Vac would be $11,840. This price includes the
blasting equipment only and not the compressed air required for operation or the
blasting grit.
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6.0 Performance Summary
This section presents the findings from
the evaluation of the Blast N'Vac for
each performance parameter evaluated.
6.1	Decontamination Efficacy
The decontamination efficacy (in terms
of %R) attained by the Blast N'Vac was
evaluated for each individual concrete
coupon used during the evaluation.
When the decontamination efficacy
metrics (DF and %R) of the eight
contaminated coupons were averaged
together, the average %R for the Blast
N'Vac was 97 ± 2% the average DF was
58 ± 52. Hypothesis testing was
performed to determine if there were
significant differences among the %R
values determined for the coupons in
each row (top, middle, and bottom) of
the test stand. No differences were
found.
6.2	Deployment and Operational
Factors
Following the manufacturer's
recommendations, the Blast N'Vac was
used with a size 24 aluminum oxide
abrasive grit. The rate at which the Blast
N'Vac was used to decontaminate a
vertical surface was approximately 2.7
m2 per hour, with significant visual
surface destruction and some secondary
waste. The texture of the concrete
surface is not relevant to the efficacy of
the Blast N'Vac and similar blasting
technologies. Battelle observed that,
because of the aggressiveness with
which the abrasive grit removes concrete
surfaces, irregularities within the surface
would not impact the effectiveness of the
technology. The Blast N'Vac required a
source of compressed air that provided at
least 400 cfm of air flow at a pressure of
120 psi. An Ingersoll-Rand 75902
diesel-powered air compressor was the
only source of power required for the
operation of the Blast N'Vac. Such a
large air compressor is not a common
piece of equipment. Therefore, the size
and availability of the compressor may
limit the locations where the Blast
N'Vac can be used.
A very limited evaluation of cross-
contamination was performed. During an
actual decontamination of a vertical
surface, the higher elevation surfaces
would likely be decontaminated first,
possibly exposing the lower surface to
secondary contamination. To simulate an
actual scenario, one uncontaminated
coupon was placed in the bottom row of
the test stand and decontaminated using
the Blast N'Vac in the same way as the
other coupons. Following
decontamination, this uncontaminated
coupon did not exhibit measurable
activity suggesting that cross
contamination was minimal. While
cross-contamination on the test stand
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seemed to be minimal, very small
amounts of blasting abrasive grit
(individual grains) were found
throughout the containment tent and
there was some abrasive grit that
collected at the base of the test stand.
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7.0 References
1.	ASTM Standard C 150-07,
"Standard Specification for Portland
Cement." ASTM International, West
Conshohocken, PA, www.astm.org.
2007.
2.	Radionuclide Detection and
Decontamination Program. Broad
Agency Announcement 03-013, U.S.
Department of Defense (DOD)
Defense Advanced Research Projects
Agency (DARPA) and the U.S.
Department of Homeland Security,
classified program.
3. Calibration and Use of Germanium
Spectrometers for the Measurement
of Gamma Emission Rates of
Radionuclides. American National
Standards Institute. ANSIN42.14-
1999. IEEE New York, NY (Rev.
2004).
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&EPA
United States
Environmental Protection
Agency
PRESORTED STANDARD
POSTAGE & FEES PAID
EPA
PERMIT NO. G-35
Office of Research and Development (8101R)
Washington, DC 20460
Official Business
Penalty for Private Use
$300

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