EPA/600/R-20/104 | September 2020
www.epa.gov/homeland-security-research
United States
Environmental Protection
Agency
oEPA
Review of Decontamination
Progress Surveying
Technologies for Wide-Area
Radiological Contamination
Office of Research and Development
Homeland Security Research Program

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EPA/600/R-20/104 | September 2020
www.epa.gov/homeland-security-research
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EPA/600/R-20/104
September 2020
Review of Decontamination Progress Surveying Technologies for
Wide-Area Radiological Contamination
U.S. Environmental Protection Agency
Office of Research and Development
Center for Environmental Solutions and Emergency Response
Research Triangle Park, NC 27711
United States Environmental Protection Agency
Office of Research and Development
Homeland Security Research Program

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Disclaimer
The research described here has been funded, in part, by the U.S. EPA Interagency Agreement,
DW-89-92426601, with Lawrence Livermore National Laboratory. It has been subjected to
review by the Office of Research and Development and approved for publication. Approval does
not signify that the contents reflect the views of the Agency, nor does mention of trade names or
commercial products constitute endorsement or recommendation for use.
Questions concerning this document, or its application should be addressed to:
Dr. Sang Don Lee
U.S. Environmental Protection Agency
109 T.W. Alexander Drive
Mail Code: E343-06
Research Triangle Park, NC 27709
Lee. Sangdon@epa.gov
919-541-4531
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Foreword
The US Environmental Protection Agency (EPA) is charged by Congress with protecting the
Nation's land, air, and water 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 research program is providing data and technical support for solving
environmental problems today and building a science knowledge base necessary to manage our
ecological resources wisely, understand how pollutants affect our health, and prevent or reduce
environmental risks in the future.
The Center for Environmental Solutions and Emergency Response (CESER) within the Office of
Research and Development (ORD) conducts applied, stakeholder-driven research and provides responsive
technical support to help solve the Nation's environmental challenges. The Center's research focuses on
innovative approaches to address environmental challenges associated with the built environment. We
develop technologies and decision-support tools to help safeguard public water systems and groundwater,
guide sustainable materials management, remediate sites from traditional contamination sources and
emerging environmental stressors, and address potential threats from terrorism and natural disasters.
CESER collaborates with both public and private sector partners to foster technologies that improve the
effectiveness and reduce the cost of compliance, while anticipating emerging problems. We provide
technical support to EPA regions and programs, states, tribal nations, and federal partners, and serve as
the interagency liaison for EPA in homeland security research and technology. The Center is a leader in
providing scientific solutions to protect human health and the environment.
Gregory Sayles, Director
Center for Environmental Solutions and Emergency Response
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Table of Contents
DISCLAIMER	II
FOREWORD	Ill
LIST OF TABLES	IV
LIST OF FIGURES	IV
ACRONYMS AND ABBREVIATIONS	VI
ACKNOWLEDGMENTS	VIII
EXECUTIVE SUMMARY	IX
1	INTRODUCTION	1
2	WIDE AREA RADIOLOGICAL CONTAMINATION	2
3	TECHNOLOGIES FOR MONITORING DECONTAMINATION PROGRESS	5
3.1	Traditional Geiger-Muller, Proportional, and Scintillation Counters	5
3.2	Compton Imaging Cameras	8
3.3	Ground-Based Mobile Surveys	11
3.4	Aerial Surveys	16
3.5	Waste Screening Techniques	18
3.6	Plastic Scintillation Fibers	20
4	SUMMARY AND CONCLUSIONS	25
5	REFERENCES	26
APPENDIX A: DATASHEETS FOR RADIOLOGICAL SURVEYING TECHNOLOGIES	32
A.l Ground Vehicle Radiation Monitoring/Surveying	33
A.2 Airborne Radiation Surveying	34
A.3 Unmanned Aerial Vehicle Radiation Surveying	35
A.4 Hand-Held Gamma and Beta Detectors	36
A.5 Gamma Cameras and Compton Imaging	37
A.6 ManualSoilSampling	38
List of Tables
Table 3-1. Characteristics of Example Ground-based Standoff Radiation Detectors (DHS 2013)	15
Table 3-2. Characteristics of JAEA Airborne Survey Systems (Reproduced from Miyahara, 2015)	17
Table 3-3. Characteristics of Example Airborne Standoff Radiation Detectors (DHS 2013)	18
List of Figures
Figure 2-1. DOE's Aerial Measuring System (AMS) survey's color-enhanced exposure-rate measurements near the
Fukushima NPP (Musolino etal., 2012)	2
Figure 3-1. Examples of Sodium Iodide Scintillation Survey Meters (MOE, 2013)	6
Figure 3-2. Examples of Geiger-Muller Survey Meters (MOE, 2013)	7
Figure 3-3. Examples of Scintillation Survey Meter Collimators (MOE, 2013)	7
Figure 3-4. Example of Gamma Camera Applications in Japan (Recreated from MOE, 2013)	8
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Figure 3-5. Photo of the LLNL Directional Radionuclide Identifier System: shown with the detector system open and
INTERNAL COVER REMOVED, NEXTTO THE TABLET THAT PROVIDES THE USER INTERFACE (LEFT). PHOTO OF A SINGLE MODULE
(right)	10
Figure 3-6. Heat Map Showing the Location of aCesium-137 Source that was Placed at 180 Degrees Azimuth by 30
Degrees Elevation	11
Figure 3-7. Directional Radionuclide Identifier System. Two arrows pointing in the direction of a source, the red one
USING COMPTON IMAGING AND THE YELLOW USING ACTIVE MASKING	11
Figure 3-8. Example Mobile Survey Road Vehicles USEPA Radiation Scanner Van (left); Japan Atomic Energy Agency
Monitoring Vehicle (right)	12
Figure 3-9. A Demonstration of KURAMA-II	12
Figure 3-10. INL's Gator, EMS, AXISS and BaSIS real-time survey systems, clock-wise from top left. (Giles etal., 2008)
	13
Figure 3-11. INL's Interior Characterization Scanning System (ICISS) deployed at Miamisburg. (Carpenter etal., 2005)
	14
Figure 3-12. Nuvia's "Groundhog" series of site survey systems: backpack-based Fusion, and vehicle-mounted Insight
and Synergy models	14
Figure 3-13. Airborne Survey Systems Corresponding to Table 4-2 (Miyahara, 2015)	17
Figure 3-14. Toshiba's Simplified Method for Measuring Radioactivity Concentration per Waste Container (MOE, 2013)
	19
Figure 3-15. Nuvia's Gamma Excavation Monitor (GEM) and High-Resolution Assay Monitor (HiRAM) systems for
MEASURING RADIOACTIVITY IN REMOVED WASTE (NUVIA, 2019)	20
Figure 3-16. JAEA Application of Plastic Scintillation Fibers in Post-Fukushima Surveys (Reproduced from JAEA, 2015b).
PSF EQUIPMENT SUPPLIED BYJREC (A); APPLICATION OF PSF TO SURVEY POND SEDIMENTS (B); APPLICATION OF PSF TO SURVEY
FOREST SOIL (C); APPLICATION OF PSF TO MEASURE OUTDOOR URBAN SURFACES, E.G., SCHOOL PLAYGROUND (D). NOTES: PMT =
PHOTO-MULTIPLIER TUBE; PC = PERSONAL COMPUTER	22
Figure 3-17. LLNL Plastic Scintillation Fiber Detector Components. Scintillation fiber optic bundle (a), digital
OSCILLOSCOPE (b), PHOTOMULTIPLIER TUBES CONNECTED BY SHORT FIBER FOR DEMONSTRATION (c), HANDHELD TABLET (d),
Raspberry Pi 3 (e), USB battery pack (f)	23
Figure 3-18. A coiled 10-meter 7-fiber PSF Bundle (with Heat-shrink Coating and Signal Delay) for Water
Infrastructure or WallSurveys	24
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Acronyms
and Abbreviations
|im
Micrometer
|iSv/hr
MicroSieverts per hour
3D
Three-dimensional
ac
Acre
AMS
Aerial Measuring System (DOE)
Am
Americium
ASPECT
Airborne Spectral Photometric Environmental Collection Technology (USEPA)
AXISS
Actinide X-Ray in-Situ Scanning System
BaSIS
Backpack Sodium Iodide System
BOMARC
Boeing Michigan Aeronautical Research Center
Bq
Becquerel
cm
Centimeter
cm2
Square centimeter
cm3
Cubic centimeter
Cs
Cesium
Csl
Cesium iodide
CsI(Tl)
Thallium-doped cesium iodide
CZT
Cadmium zinc telluride
DHS
Department of Homeland Security
DOE
U.S. Department of Energy
EMS
Excavation Monitoring System
ETCC
Electron-tracking Compton camera
ES&H
Environmental, Safety, and Health
FSU
Former Soviet Union
FWHM
Full-width, half-maximum
Ge
Germanium
GIS
Geographic Information System
GM
Geiger-Muller
GPS
Global Positioning System
GYGAG
Cerium-doped gadolinium yttrium gallium aluminum garnet
ha
Hectare
HPGe
high purity germanium
hr
Hour
IAEA
International Atomic Energy Agency
IEEE
Institute of Electrical and Electronics Engineers
IND
Improvised Nuclear Device
INL
Idaho National Laboratory
I
Iodine
JAEA
Japan Atomic Energy Agency
kBq/m2
kilobecquerel per meter squared
keV
Kiloelectron volt
kg
Kilogram
Km
Kilometer
km/hr
kilometer per hour
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KURAMA
Kyoto University RAdiation MApping System
LLNL
Lawrence Livermore National Laboratory
m2
Square meter
mm
Millimeter
mph
miles per hour
m/s
meters per second
MEXT
Ministry of Education, Culture, Sports, Science & Technology (Japan)
|im
micrometer
mSv
millisievert
MOE
Ministry of the Environment (Japan)
N/A
not available
Nal
Sodium-iodide
Nal(Tl)
Thallium-doped sodium iodide
NPP
Nuclear Power Plant
PMMA
Poly(methyl methacrylate)
PC
Personal Computer
PMT
Photo-multiplier tube
Pu
Plutonium
PSF
Plastic scintillation fiber
PSI
Pounds per square inch
Rb
Rubidium
RDD
Radiological Dispersal Device
Sr
Strontium
SUV
Sports utility vehicle
UAV
Unmanned aerial vehicle
UK
United Kingdom
U.S.
United States
USB
Universal Serial Bus
U02
Uranium dioxide
USEPA
U.S. Environmental Protection Agency
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Acknowledgments
Contributions of the following individuals and organization to this report are gratefully
acknowledged:
US EPA Project Team
Sang Don Lee Office of Research and Development, Center for Environmental Solutions
and Emergency Response (ORD/CESER), Homeland Security and Materials
Managements Division (HSMMD)
Matthew Magnuson ORD/CESER/HSMMD
Lawrence Livermore National Laboratory
Hiroshi Saito, Mark Sutton, Pihong Zhao and Erik Swanberg
US EPA Technical Reviewers of Report
Kathy Hall, ORD/CESER/HSMMD
Scott Hudson, Office of Land and Emergency Management, Office of Emergency
Consequence Management Advisory Division
US EPA Quality Assurance
Ramona Sherman
Joan Bursey (Technical Editing)
Booze Allen Hamilton
Katrina McConkey (Editing)
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Executive Summary
The continuing threat of terrorist attacks against the United States has provided great impetus for
the development of methods and technologies that can be utilized to detect and interdict terrorist
threats, and to effectively respond to and recover from terrorist attacks. One of the greatest
concerns facing the United States and other nations is the use of radiological weapons by
terrorist organizations. The explosive radiological dispersal device (RDD) has become the
paradigm for malicious dispersal of radioactive material. Such an RDD would not immediately
result in great loss of life, as casualties would be limited to those resulting from the explosion
rather than from the associated radioactivity. Rather, fear, social and economic disruption, and
long-term health effects are the primary concerns. The RDD is considered a denial of area
weapon because it can spread radioactive contamination over a large area halting the regular
flow of business and commerce and forcing relocation of businesses and residents while lengthy
and very costly decontamination takes place.
Radiological decontamination technologies currently available for use after an urban RDD attack
are costly and time consuming to deploy and may be unacceptably destructive to urban surfaces.
Therefore, research and development efforts are urgently needed to better prepare for response
and recovery from an RDD event. An improvised nuclear device (IND) would result in a range
of radioactivity levels, radionuclide types, and particulate properties. A radiological accident at a
nuclear power plant would result in a mixture of water soluble and insoluble radionuclides.
Portions of higher radiological contamination were observed in an area surrounding several
buildings near the Fukushima nuclear power plant (NPP). If these measurements are reflective
of sub-surface contamination, proper site survey before decontamination and proper assessment
methods for decontamination progress could significantly reduce overall cost and time for
decontamination, the waste volume generated in a wide area incident, and the time before
unsupervised access can be permitted to the previously contaminated site. More research is
recommended to fully identify the circumstances and the extent to which this advantage can be
exploited.
A variety of technologies and platforms exist (likely often used in combination) for surveying
contaminated areas, and for monitoring the progress of decontamination/dose reduction to suit
the survey area size, terrain, and desired resolution. New technologies are currently being
developed in Japan and in the United States, both of which merit possible inclusion in domestic
RDD or IND response.
Individual technologies for surveying/monitoring contaminated areas are briefly summarized in
the sections that follow, with additional details outlined in the attached appendix.
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1 Introduction
Radiological contamination stemming from nuclear facility accidents, intentionally dispersed
radionuclides or an improvised nuclear device (IND) can lead to large areas requiring
remediation. A broad range of expertise and capabilities have been tried and tested for surveying
and removing contamination from buildings and sites at commercial and research nuclear
facilities and the United States (U.S.) Department of Energy (DOE) complex sites. However,
recovery following a nuclear/radiological facility contamination event can differ greatly from a
wide-area urban effort in many ways, including magnitude, timeframe, urgency, cost and
stakeholders, as well as social and economic impacts. Rapid and safe remediation will be the key
component of the response and recovery from a wide area radiological incident.
Proper site survey before decontamination and proper assessment methods for decontamination
progress can reduce cost and time for decontamination and reduce the waste volume especially in
a wide area incident. Wide area contamination as seen Chernobyl and Fukushima incidents
requires extensive areal decontamination to effectively reduce radiation dose due to high
surrounding radiation level. In this situation it is difficult to confirm the effectiveness and
progress of decontamination. This leads to uncertainty that can potentially delay decontamination
progress or unnecessarily result in a redo of decontamination work. This report identified the
available surveying technologies that can improve wide area decontamination.
A variety of equipment technologies and platforms exist (likely often used in combination) for
surveying contaminated areas, and for monitoring the progress of decontamination/dose
reduction activities to suit the survey area size, terrain, and desired resolution. Limited data are
available assessing survey equipment/technology accuracy. New survey technologies are
currently being developed in Japan and in the United States, both of which merit possible
inclusion in domestic RDD or IND response. This report evaluates equipment technologies that
can be used for survey and monitoring activities following RDD, IND, and NPP contamination.
Additionally, techniques for identifying and mapping contamination, and for monitoring
decontamination progress are discussed. Prior technology reviews from five major resources
were leveraged: 1. U.S. Environmental Protection Agency (USEPA) reports; 2. International
Atomic Energy Agency (IAEA) reports; 3. Reports related to major NPP accidents, such as
Fukushima and Chernobyl accidents; 4. Literature related to nuclear weapons tests and accidents
sites (including but not limited to U.S. Department of Energy, DOE reports); 5. Literature
reviews of recent publications following the Fukushima accident. The review focused on
survey/equipment technologies, publications, technical reports and vendor information produced
(or made available) since JAEA (Japan Atomic Energy Agency) reviews performed in 2012. To
the extent possible, the purpose of this review is to provide quantitative metrics for comparing
available technology costs, availability and technical performance that shall be applicable for
wide area incident response. Individual technologies for surveying/monitoring contaminated
areas are briefly summarized in the sections that follow, with additional details outlined in the
attached appendix.
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2 Wide Area Radiological Contamination
Scenarios for the wide-area release of radiological particulates can include nuclear reactor
meltdowns, undetonated nuclear warhead accidents, RDDs, and nuclear detonations. The size of
contaminated areas from these scenarios can vary widely: 50.9 TBq over seven sites totaling
5000 nr and distributed over an area of 2 km2 in the central districts of Goiania, Brazil; (Vinhas.
2003); a nominal 60 square mile dangerous fallout zone for a 10 kiloton nuclear device (IPCS.
2010); -760 square miles of surveyed areas with >1 mSv annual dose surrounding the
Fukushima Daiichi Nuclear Power Plant (IAEA. 2015); and 77,000 square miles above >40
kBq/m2 cesium-137 (137Cs) contamination caused by the Chernobyl nuclear reactor meltdown
(IAEA. 2006). Limited literature was found characterizing identified contaminants from these
scenarios. The literature points to a wide radioactive particle size range (<10 micrometer [p.m]
to fragments) and possibly thin layers or films in some cases.
Portions of higher radiological contamination were observed in an area surrounding several
buildings near the Fukushima NPP (Musolino et al.. 2012). If these measurements are reflective
of sub-surface contamination, proper site survey before decontamination and proper assessment
methods for decontamination progress could significantly reduce overall cost and time for
decontamination, the waste volume generated in a wide area incident, and the time before
unsupervised access can be permitted to the previously contaminated site. As wide area
contamination is often assumed to occur uniformly, universal removal of surface material may
produce an enormous amount of waste and also it will increase the labor and time for
remediation. A hot spot focused decontamination approach likely requires precise identification
of hot spot size and location, which may be challenged by background radiation affecting
decontamination efficacy measurements in a wide area incident. Proper measurements require
collimation of the radiation source and close proximity to surfaces. A combination of different
surveying methods may be able to achieve this, depending on the contaminants, contamination
levels, area sizes, and contamination depths. More research is recommended to fully identify the
circumstances and the extent to which this advantage can be exploited.
Figure 2-1. DOE's Aerial Measuring System (AMS) survey's color-enhanced exposure-rate
measurements near the Fukushima NPP ( lusolino et al., 2012)
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An RDD is a conventional bomb designed to disperse radioactive material to cause destruction,
contamination, and radiation injury - an RDD does not produce a nuclear yield like a
conventional or improvised nuclear device (CIA. 2003). A cited "benchmark" for an RDD is the
1987 Goiania incident in Brazil involving the human dispersion of the radioactive cesium-137
chloride powder from a stolen and broken radiotherapy radiation source, leading to 4 deaths and
244 people exposed (Magill, 2007). Two potential sources of materials for RDDs due to their
prevalence include commercial radioactive sources and nuclear fuel. Commercial sealed
radiation sources often contain powders like cesium chloride and sometimes radium-226
bromide/chloride, sintered solids such as strontium-90 (90Sr) fluoride, and metals like cobalt-60
(Peterson. 2007). However, RDD radioactive material could be purposefully altered physically
and chemically as part of the device design as well as a result of the "dirty bomb" explosion to
potentially include oxides and/or nitrates (from the explosive) over a wide particle size range.
Nuclear reactor fuels can come as uranium dioxide (UO2), mixed-oxides (a mixture of uranium
and plutonium [Pu] oxides), uranium metals or their alloys, and microspheres (uranium or
thorium oxide) as well as less common forms (Bodamsky. 2004).
The most extensive characterization of nuclear-incident-produced radiological particulates found
were those resulting from nuclear weapons detonation tests by the U.S. and UK. Nuclear
detonations of American weapons containing both uranium-235 and plutonium-23 9 at Enewetak
Atoll (QUI 11>82) created objects near "ground zero" that were plated with thin layers or films
of plutonium and fission products (e.g., americium-241 [241Am], 137Cs, 90Sr) while radioactive
particles rose to great heights before settling back to Earth or being washed down by rain. These
particulates range from occasional milligram-sized Pu metal pieces to those similar to soil
particle sizes. Plutonium-239 (239Pu), plutonium-240 (240Pu), 241 Am (produced by beta decay of
plutonium-241, a small part of Weapons-Grade Pu) and plutonium-23 8 (238Pu) were the alpha
emitters seen in significant amounts. Contaminated metal debris were also found in one area
when the device failed to yield fission. Milligram-sized and larger radioactive fragments as well
as Pu-contaminated beryllium were detected on-site from plutonium-device safety tests
(Hamilton. 2009). United States land-based Bikini Atoll nuclear weapons tests (DNA. 1981)
produced dry white, opaque and irregularly shaped particles (-15 - 1000 |im diameter, many
particles flaky) as well as non-crystalline spheroidal particles (likely nuclear device components
and fission products). One site sample suggested 33% of the activity from >225 |im particles,
and -20% of the activity in <10 |im particles with specific activity decreasing with increasing
particle size. Fallout decay activity also included beta disintegrations, gamma photons, and
gamma ionization. United Kingdom weapons tests at Maralinga in south Australia (Burns. 1995)
also created plutonium-coated pieces (metal, plastic, wire, etc.), tiny fragments/particles
sometimes not visible to the eye, and very finely divided material in the inhalable range similar
to soil particles. A portion of the Pu contamination in the soil existed as 95% of
the identified particulates were UO2 reactor fuel particles generated by mechanical fuel
disintegration and <3% were attributed to condensation particles (<1 |im) produced from
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volatiles such as cesium (-134 [134Cs], -137), iodine-131 (131I), and rubidium-87 (87Rb) within 10
km of the nuclear plant. Fine condensation particles made up -60% and 98% at 25 and 65 km,
respectively, from the reactor, while >65% of the total activity came from nuclear fuel particles
in the 30 km around the nuclear power plant. Chernobyl-produced particles were reported to be
crystalline due to their release at high temperatures (Kreklii 8). Identified particulates
from the Fukushima Dai-ichi Nuclear Power Plant were aerosols (-0.1 - 2 |im) volatilized due to
the reactor meltdown that collected radioactive cesium and iodine while airborne and came down
by dry deposition (Kristiansen. 2012). Some isolation and characterization of larger particulates
(up to -6.4 |im diameter) from the Fukushima accident has recently begun (Sato. 2016).
Later forensic analysis of the 1960 Boeing Michigan Aeronautical Research Center (BOMARC)
"broken arrow" (non-nuclear explosion of fire involving a nuclear weapon) missile incident
found generally crystalline/smooth Pu particles with varying uranium content and with 15-65 |im
lateral dimensions (Bowen. 2013). This contrasted with the particulates collected from the 1966
Palomares, Spain and 1968 Thule, Greenland hydrogen bomb incidents which were fluffy
amorphous or agglomerated grains (popcorn-like).
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3 Technologies for Monitoring Decontamination Progress
After an RDD, IND or accidental radiological release from a nuclear facility such as an NPP,
radioactive contamination may be dispersed over a wide area, affecting a variety of land use,
from rural and agricultural to urban. Surveying and characterization of the radionuclides present
after an RDD, IND, or NPP release is vital in understanding the stabilization and
decontamination necessary. Monitoring is also needed during decontamination (to evaluate
progress) and after decontamination (to clear an area). Decontamination effectiveness can be
determined by measuring the radioactivity or dose remaining on the surface compared to before
cleaning began, or by measuring the waste generated from cleaning activities (mass balance). In
this section, we consider both repeated measurement of surfaces and measurement of waste
generated from decontamination activities, as well as deployment of monitoring devices on land
and in the air.
3.1 Traditional Geiger-Muller, Proportional, and Scintillation Counters
Historically, responses to several nuclear accidents resulting in wide-spread contamination offer
examples of simple surface surveying techniques. For example, following the Chernobyl nuclear
accident, gamma spectrometry deployed on helicopters was used to map contamination, and
germanium (Ge) detectors and sodium iodide (Nal) scintillation counters with lead shielding
were used to measure roofs, walls, and soil (Hoed. 1995V Similarly, following the compromise
of a 137Cs medical isotope source in Goiania, surveying employed the use of hand-held monitors
including Geiger-Muller (GM) tubes, proportional counters, and scintillation detectors.
Proportional counters were found to have poor robustness. Scintillation counters designed for
geological surveying provided low limits of detection, fast response time, and were very useful
in determining hotspots. To protect against the ambient environment (including contamination
and rain-water), monitors were placed in plastic bags, which hindered handling and reading
(	I)-
Much can be learned from Japan's recovery efforts following the Fukushima Daiichi accident,
particularly in the detailed application of traditional survey meters to assess contamination and
determine the efficacy of decontamination efforts, as well as the development of newer survey
technologies and novel deployment of traditional technologies. Monitoring of contamination and
subsequent decontamination progress in Japan has been defined by its Ministry of the
Environment (MOE) document titled "Decontamination Guidelines" (MOE.: ), specifically
citing "Ordinance for Enforcement of the Act on Special Measures concerning the Handling of
Radioactive Pollution (Portion relevant to the Methods for Investigating and Measuring the
Status of Environmental Pollution in Intensive Contamination Survey Areas)", "Article 43: The
investigation and measurements specified in Article 34, Paragraph 1 of the Act shall be
conducted according to the following requirements:
1.	The status of environmental pollution due to radioactive materials discharged by the
accident shall be represented in terms of the radiation dose.
2.	The radiation dose shall be measured using radiation measuring equipment that can
accurately detect the measured value.
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3.	The radiation dose shall be measured at a point 50 to 100 centimeter (cm) above the
ground.
4.	The radiation measuring equipment shall be regularly calibrated at least once a year."
Air dose rate (by Nal or cesium iodide [Csl] scintillation survey meter), surface dose rate (by
collimated Nal or Csl scintillation survey meter) and surface contamination density (by GM
survey meter) have typically been recorded in Japan. Examples of Nal scintillation survey
meters used in Japan to perform measurements of contamination and decontamination progress
are shown in Figure 3-1 (Decontamination Guidelines 2013). Similarly, GM survey meters used
in Japan are shown in Figure 3-2 (Decontamination Guidelines 2013), and collimators used to
reduce the field of view in Nal scintillation survey meters are displayed in Figure 3-3 (MOE,
2013). Thallium-doped cesium iodide or CsI(Tl), scintillators offer greater luminosity and
narrower energy resolution than thallium-doped sodium iodide or (Nal(Tl), scintillators.
Figure 3-1. Examples of Sodium Iodide Scintillation Survey Meters (MOE, 2013)
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Figure 3-2. Examples of Geiger-Muller Survey Meters ( lOK, 2013)
Figure 3-3. Examples of Scintillation Survey Meter Collimators (VtOE, 2013)
As of March 2017, decontamination in the Japanese Special Decontamination Areas has been
completed for 22,000 hectare [ha], 8,500 ha, 5,800 ha and 1,400 ha, respectively (54,000 acres
(ac) of residential area, 21,000 ac of farmland, 14,000 ac of forest close to residential areas, and
3,500 ac of roads) (MOH. 2017). Decontamination progress in these areas was measured via air
dose rate at a height of 1 meter (m) above ground level. Additionally, MOE demonstrated the
use of a Nal scintillator attached to a long extension pole or washing-line pole to reach higher
surfaces including roof gutters (VIOH, 2015).
Handheld methods are very labor-intensive and cover only a small surface area, so the speed of
application can be extremely slow, especially for wide areas and urban areas. Having mobile
detection can significantly speed up the surveying of surfaces. Such mobile detection can be
ground-based or aerial, with each one having pros and cons. Aerial mapping of the
contamination can cover large areas quickly and is not dependent on road/terrain. However,
aerial surveys do not have the same level of precision on location in the survey area that ground-
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based surveys can provide. Conversely, ground-based surveys can be slow to perform and are
limited by access for a given terrain (e.g., road or rail). Personnel-based surveying can also be
performed using backpack-style meters. Several U.S. government agencies such as DOE,
Department of Defense and EPA have survey capabilities including ground-based detection in
cars, trucks and vans, and aerial vehicles such as planes and helicopters.
3.2 Compton Imaging Cameras
Compton imaging cameras are advanced imaging tools for locating radioactive sources which,
when paired with image software, improve the probability of distinguishing between the source
and background radiation. Such techniques are designed to identify radioactive material
concentrated in a single location, with the background radioactivity spread over a large area.
Combining visual images with gamma measurements makes locating areas of elevated
contamination easier, particularly for those with little training in gamma measurement. Compton
imaging has several advantages over conventional gamma imaging techniques including the
ability to survey a large field of view with good background suppression. They offer increased
efficiency and more compact/mobile design compared with gamma imaging. An example
gamma camera application was recommended in the MQE decontamination guidance (MQE,
2013) and is recreated in Figure 3-4.
Camera	Field measurement
Distance
Camera image information
TF :'
Distribution of	Combined visual and
measurements	gamma images
Figure 3-4. Example of Gamma Camera Applications in Japan (Recreated from MQE, 2013)
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Mitsubishi demonstrated a gamma camera to image 137Cs contamination in a parking lot and on a
house in the Fukushima area both before and after decontamination (Matsuura. 2014). The tests
identified a 20 micro-Sieverts per hour (|j,Sv/hr) hot-spot in a parking lot after a 30-minute count
time under a 1.5 |j,Sv/hr air dose (background) 1 m from the camera and another hot-spot of 30
|j,Sv/hr at a distance of 10 m from the camera.
Additionally, technology developed by Chiyoda Technol Corporation1 presented at the 2015
symposium on radiological issues associated with the revitalization of Fukushima highlighted the
use of a lightweight Compton gamma camera for monitoring surface contamination during
decontamination efforts. Such techniques permit both the identification of contamination, and a
measure of decontamination progress. Compton gamma cameras are being developed at several
DOE sites to support DOE, Department of Homeland Security (DHS) and IAEA radiological
search capabilities (Drever. 2014). Such cameras should be made more widely available in
response to wide-area radiological events, allowing remediation workers to locate contamination
and monitor the progress of decontamination. Disadvantages of this technology for wide area
decontamination are its high cost (low availability), specially-trained operators, and inaccurate
location in complex geometry due to Chiyoda's device being a gamma camera designed to find
nuclear smuggling in well-characterized conditions rather than for broad contamination outdoors.
The Directional Radionuclide Identifier (Dr. ID) developed by Lawrence Livermore National
Laboratory (LLNL), shown in Figure 3-5, uses pixels of cerium-doped gadolinium yttrium
gallium aluminum garnet (GYGAG) scintillators. The garnet has the crystal structure
(Gd,Y,Ce)3 (Ga,Al)50i2. A single pixel energy resolution near 3% full width at half-maximum
(FWHM) at 662 kiloelectron volt (keV) has already been demonstrated with these pixels and can
be increased to 4.7% when using Compton-summed events for all pixels (Swanberg, 2018). The
pixels are transparent ceramics, not single crystals, formed by several stages of pressing and
heating of nano-powders. They are mechanically rugged, readily machinable, unreactive to air
and water (facilitating packaging), have good light yield of -50,000 photons per milli-electron
volt, a density of 5.8 grams per cubic centimeter (cm3), high effective atomic number of
approximately 48, and good light yield proportionality (Cherepy et at.. 2013). The main
limitations of Dr.ID for wide area survey work are due to its current design, which seeks out a
single radiation source (can suffer when multiple sources or hotspots are present), and provides
only source direction without a distance determination required for mapping (may require
multiple measurements for triangulation or possibly overlaying the radiation field on an image of
the scene). Dr. ID also has poorer energy resolution, and hence spatial resolution, than popular
semiconductor detectors (CZT (Cadmium zinc telluride) and HPGe (high purity germanium)),
although at lower cost per unit volume.
1 htlp ://www. c-techno Lco.jp/eng
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Figure 3-5. Photo of the LLNL Directional Radionuclide Identifier System: shown with the detector
system open and internal cover removed, next to the tablet that provides the user interface (left).
Photo of a single module (right).
The Dr. ID system is constructed from detector modules and were originally developed for
medical imaging. Each detector module includes a photodiode array, application-specific
integrated circuit readout technology, and Universal Serial Bus (USB) interface. The pixelated
architecture is leveraged to provide directional information utilizing Compton imaging with
active masking. When a gamma Compton scatters in one pixel and is photo-electrically
absorbed in a second pixel, the energies and locations of the interactions can be used to back-
project to where the gamma originated. Summing this information over many such interactions
allows a three-dimensional (3D) map to be constructed showing the location of sources or hot
spots. Active masking techniques utilize pixels closer to a source to create shadows on pixels
further away. This can be used to determine the direction to a hot spot or source. It does not
provide a 3D map of multiple hot spots like Compton imaging, but it is typically faster at
locating single sources or hot spots. The two methods are complimentary since Compton
imaging works better with higher energy gammas (above about 250 keV) and active masking
works better at lower energies. Imaging algorithms using active masking and Compton imaging
techniques have already been developed and applied to the Dr. ID array. (See Figures 3-6 and 3-
7).
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80
60
c
o
| 40
0)
HI
20
0
0	50	100	150	200	250	300	350
Azimuth
Figure 3-6. Heal Map Showing the Location of a Cesium-137 Source that was Placed at 180 Degrees
Azimuth by 30 Degrees Elevation
Figure 3-7. Directional Radionuclide Identifier System. Two arrows pointing in the direction of a
source, the red one using Compton imaging and the yellow using active masking.
3.3 Ground-Based Mobile Surveys
Japan Atomic Energy Agency (JAEA) has also applied modern detection technology to a sports
utility vehicle (SUV) with Global Positioning System (GPS), fielded from the Sasakino
Analytical Laboratory, shown in Figure 3-8. The detection systems on the vehicle can measure
both low and high dose rate ranges, specifically 0.01 to 10 jj,Sv/hr using a shielded thallium-
doped sodium iodide [Nal(Tl)] scintillation detector, and up to 100,000 (.iSv/hr using semi-
conductor detector technology. The multiple detectors present on the vehicle can measure
ambient dose as well as ground measurements (with the latter detector pointed downward). Dust
and gas sampling can measure alpha- and beta- emitting radionuclides in airborne particles and
capture radioactive iodine. The vehicle can transfer data real-time to a base station, can travel
off-road (particularly important for emergency response) and has a moveable searchlight for
night operation. Discussions with JAEA also determined that driving through contaminated
areas resulted in vehicle contamination that was not easily removed with typical vehicle washing.
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Additionally, air-filters and cabin filters became contaminated. Similar issues should be
considered in U.S. deployments of such technologies.
Figure 3-8. Example Mobile Survey Road Vehicles USEPA Radiation Scanner Van (left); Japan
Atomic Energy Agency Monitoring Vehicle (right)
Survey equipment has also been developed at the Kyoto University. The Kyoto University
RAdiation MApping (KURAMA) System measures dose every 3 seconds and is deployed in a
minivan with GPS and linked to Google Earth. However, KURAMA requires an operator and a
complicated set-up. Subsequently, KURAMA-II has been developed in a compact (30 x 20 cm),
lightweight form with autonomous pulse-height spectra utilizing a thallium-doped cesium iodide
[CsI(Tl)] scintillation detector. Both systems have been successfully demonstrated in
contaminated areas in the Fukushima region. By deploying KURAMA-II instruments in 28
buses, two prefecture cars and 19 service-operated cars, data is transmitted real-time to IAEA
and displayed on a large screen in the IAEA Fukushima Office lobby (TanjgakL 2015). Kyoto
University and IAEA have now deployed 100 KURAMA-II instruments across eastern Japan.
KURAMA-II is small enough to deploy on a motorcycle (as shown in Figure 3-9) and backpack
(Tsuda et al.. 2015; Tanigaki, 2015).
Figure 3-9. A Demonstration of KURAMA-II
The KURAMA-II program has the potential to be expanded to include other service vehicles,
including garbage trucks, street sweepers, mail and parcel delivery trucks. Such detectors with
real-time feedback have the potential to "crowd-source" data if the program were to be
expanded. Such a network of highly portable, service-vehicle mounted detectors with real-time
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feedback to inform both government and residents about dose should be planned for a US
response to wide-area radiological emergencies.
In the late 1990s and 2000s, the Idaho National Laboratory (INL) developed a series of mobile
survey systems, outdoor and one indoor, that were deployed at various nuclear facilities in the
United States as well as in the United Kingdom (Harwell, England and Dounreay, Scotland).
Deployed at the Fernald and Mound, Ohio, sites were the Gator, Excavation Monitoring System
(EMS), Actinide X-Ray in-Situ Scanning System (AXISS) and the Backpack Sodium Iodide
System (BaSIS) real-time survey systems (Giles et al.. 2008). All equipped with GPS tracking
connected to a data acquisition and processing computer system; the Gator was an All-Terrain
Vehicle (ATV)-mounted while BaSIS was a backpack mounted Nal detector system (Figure 3-
10). The EMS was an excavator shovel-mounted surveyor for trenches equipped with both Nal
and HPGe gamma-spectrometry systems. AXISS a cart-mounted large-area proportional
counting (LAPC) system. The Interior Characterization Scanning System (ICISS) deployed at
the Miamisburg site (Figure 3-11) was a rolling cart system that positioned desired alpha and
gamma detectors next to walls and ceiling surfaces, and other interior building fixtures (i.e.,
lights, ventilation ducts, etc.) to perform scan or point-and-shoot surveys (Carpenter et al.. 2005).
Figure 3-10. INL's Gator, EMS, AXISS and BaSIS real-time survey systems, clock-wise from top
left. (Giles et al.. 2008)
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Figure 3-11. INL's Interior Characterization Scanning System (ICISS) deployed at Miamisburg.
(Carpenter et al., 2005)
British company Nuvia, which has a Canadian office, currently deploys by contract a GPS-
equipped suite of "Groundhog" survey systems (Nuvia, 2019) very similar to those developed at
INL, ranging from the backpack-mounted "Fusion" to the tractor-mounted "Synergy" systems,
whose models can include Nal and/or advanced gamma radiation spectrometers (Figure 3-12).
Survey results are claimed to have less than 1-hour turnaround times. Early versions of the
Groundhog systems were used at sites such as Dounreay, Scotland for beach surveys for
radioactive particles and a former radium production site using sodium iodide detectors between
76 x 76 mm and 76 x 400 mm housed in environmental cases either singly or in groups (Davies,
2003).
Figure 3-12. Nuvia's "Groundhog" series of site survey systems: backpack-based Fusion, and
vehicle-mounted Insight and Synergy models
By comparison, several stand-off radiation search detectors were evaluated in a market survey
report by DHS (2013). the characteristics of which are shown in Table 3-1 and can be deployed
on vehicles.
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Several stand-off radiation search detectors evaluated by DHS (2013) include Bubble
Technology Inc's FlexSpec Mobile™ (left/right directionality, $260k integrated with Chevy
Tahoe), LFIR Radiation Inc's iFind Compton Camera 442™ (two-plane measurement,
truck/trailer mounted, $600k to $1.2M), Innovative American Technology Inc's Mobile
Radiation Verification System™ (vehicle mounted or stand-alone 360-degree horizontal field of
view, 175k without vehicle). However, these technologies specifically do not address mapping
contamination on roads or freeway surfaces. Other portable systems such as Innovation
American Technology Inc's Rapid Deployment Radiation Verification System™ ($75k), Mirion
Technologies Inc's SPIR-Ident Mobile Monitoring System™ ($285k), Nucsafe Inc's Guardian
Predator Portable Radiation Detection Kit™ (cost unknown), ORTEC's Detective-200 ($95k)
and Thermo Fisher Scientific Inc's Matrix Mobile ARIS™ (cost unknown) can be deployed on
vehicles. However, these portable units require a large stand-off distance and are typically used
for measuring field of view, not down-looking surface measurements. Down-looking
measurements would result in a small coverage area and would require many parallel passes to
cover a road or freeway. This presents an opportunity to further develop vehicle-based gamma-
survey equipment using plastic scintillation fiber (PSF further described in section 3.6) with
close proximity to road and freeway surfaces. One significant challenge posed by attempting to
measure decontamination progress in the middle of a contaminated area is the high background.
Measurements need to be close to the surface being measured, and/or well collimated in order to
accurately assess a reduction in contamination.
Table 3-1. Characteristics of Example Ground-based Standoff Radiation Detectors (DHS 2013)
Company
Product
(lam ma
Dimensions
Weight
2013 Cost
Product


Detectors
L \ \\ \ II
(cm)
(kilogra
in. kg)
(Sk)
Website
liuhhk-
l'k"\S|VC
l.cfl null I
<¦)<¦) \ 137 \ w|
24l> 5
ll>5 2

Technology
Inc.
Mobile™
directionality,
Nal(Tl)



ech.ca
LFIR
iFind
Two-plane
203 x130x
900.4
600-
www.flir.co
Radiation
Compton
measurement,
193

1,200
m
Inc.
Camera
442™
truck/trailer
mounted,
Nal(Tl) and
polyvinyl
toluene




Innovative
Mobile
Vehicle
64 x 114x99
105.2
175
wwwia-
American
Radiation
mounted or



tec.com
Technology
Verification
stand-alone 360-




Inc.
System™
degree
horizontal field
of view, Nal(Tl)




Innovation
Rapid
Nal(Tl)
71 x81 x81
68.0
75
wwwia-
American
Deployment




tec.com
Technology
Inc.
Radiation
Verification
System™





Page 15 of 39

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Com
Prod ii cl
(i
-------
Table 3-2. Characteristics of JAEA Airborne Survey Systems (Reproduced from Mivahara, 2015)
Survey
Area
Small < 1 km2
Local > 1 km2
Semi-Regional >
100 km2
Regional >1000 km2
Option
Micro UAV
Unmanned helicopter
Unmanned airplane
Manned helicopter
Altitude
< 10 m
~ 50 m
~ 150 m
-300 m
Features
Allow focused
surveys e.g., above
urban areas or in
forests; under
development
Higher resolution
mapping available
Allows remote
controlled long-time
flight (e.g., 6 hours);
under development
Standardized
methodology
available for efficient
regional surveys
Increasing:
cost, altitude, fuel, range, maintenance, pilot qualifications, ground support
Figure 3-13. Airborne Survey Systems Corresponding to Table 4-2 ( liyahara, 2015)
Manned aerial vehicles typically fly at higher altitudes, covering larger areas faster, but
producing lower resolution images. By contrast, micro UAV can cover significantly less area
than the larger aircraft, but can fly much closer to the ground, providing fine resolution.
Unmanned aerial vehicles also offer the ability to go in otherwise inaccessible locations, such as
under tree lines, between buildings, under bridges, etc. The UAV technology also has the ability
to map contamination on buildings (e.g., high-rise walls/roof), which could greatly assist in the
planning for and execution of decontamination, and subsequent clearance measurements.
Clearly, the cost, fuel usage, range, maintenance, ground support and pilot qualifications increase
from small UAVs to unmanned helicopters, planes and manned aerial vehicles such as fixed
wing or helicopters. Researchers at Chiba University in Japan also demonstrated a low-cost
UAV with a highly efficient spatial radiation monitoring system to survey low-ground regions
and residential areas, as well as forests and wasteland where walking survey was previously
impossible (MOIL 2013). The UAV, which flies between 1 and 3 m above the ground, also
includes a hyper-spectral aerial photographing system that can obtain continuous spectrum
between the visible and near infrared region to determine land cover classification and
Geographic Information System (GIS).
Surveys of contaminated land have been performed by Martin et al. (2016a; 2016b; 2016c) using
a combination of a lightweight gamma-ray spectrometer with a small volume (1 cm3)
uncollimated cadmium zinc telluride coplanar-grid detector mounted on a small unmanned
aircraft (drone). The results obtained provided high spatial resolution mapping of contamination
and progress of decontamination on land and rooftops. The technique provides for ease of
operation and upkeep, while minimizing cost and time to deploy. Disadvantages include shorter
flight times (limited fuel) and greater dependence on weather conditions. In addition, the
Page 17 of 39
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software allows for radioactive decay and depth attenuation corrections, with the results
providing an assessment of transport into neighboring substrates and locations. Since the vehicle
is small and the resolution is high, it is feasible these detectors mounted on drones may be used
to map walls and roads with great maneuverability.
Compton imaging cameras have been used to map on-site contamination in Japan by researchers
at Kyoto University ("Tomono, 2013 and 1 ; fanimori, 2017). Utilizing electron-tracking
Compton camera (ETCC) measurements, true images of gamma-emitting contamination can be
made showing location, intensity and gamma spectrum. This is particularly useful in identifying
hotspots. Demonstrations of the technique included assessments of a decontaminated pavement
surrounded by contaminated bushes, contaminated ground in a high ambient dose area, and a
decontaminated parking lot in a low dose area.
The regional manned helicopter fielded by JAEA is similar to aerial survey equipment deployed
as DOE's fixed wing and helicopter AMS2, USEPA's ASPECT3 and other commercially
available standoff detection systems as detailed in Table 3-3 (DBS. 2013). It is recommended
that the deployment of radiation detection on UAVs be further evaluated in the U.S.
Table 3-3. Characteristics of Example Airborne Standoff Radiation Detectors (DBS 2013)
Company
Product
(lam ma
Dimensions
Weight
2013
Product Website


Detectors
1. \ \\ \ II
(cm)
(Ivji)
Cost
(Sk)

Mirion
SPIR-Ident
Nal(Tl)
33 x 43 x 89
117.9
285
www.mirion.com
Technologies
Mobile





Inc.
Monitoring
System™





Nucsafe, Inc.
ARDIMS
Aerial Pod
System™
Nal(Tl)
33 x185 x
185
81.6
N/A
www.nucsafe.com
Rad Solution
RS-500
Nal(Tl)
74x56x28
113.4
N/A
www.radiationsolutions
Inc.
Digital
Airborne
Gamma-Ray
Spectrometer




.ca
Notes: N/A = not available
3.5 Waste Screening Techniques
Of the 58 techniques that were selected by MOE between 2011 and 2014, only two techniques
were in the survey and characterization category, of which only one was a ground-based
technology to simplify the measurements for radioactivity concentrations in waste containers.
http://www.nnsa.ene rgv.gov/abontns/onrprograms/emergenCTOperatlonsconiiterterrorism/respondingtoemergencies-
(M)
3 https://www.epa.gov/emergencv-response/aspect
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The Toshiba Corporation developed an integrated device that measures activity, surface dose rate
and the shape of container unit in the field and calculates the total activity in the container. This
technique, demonstrated with incineration ash and soil (Figure 3-14), improves working
efficiency and reduces the radiation exposure to workers. Using two germanium detectors, the
device can account for heterogeneity, measuring to within an error of 35%, with detection limits
of 770 Becquerel (Bq) per kilogram (kg) of Cs-137 after just one minute (MOM. 2013). Longer
count times will improve statistics (MOM. 2013).
Figure 3-14. Toshiba's Simplified Method for Measuring Radioactivity Concentration per Waste
Container ( »1()E, 2013)
The feasibility of Compton imaging of nuclear waste for characterization and treaty verification
was evaluated by Phillips (1997). In waste characterization, unless the container is to be opened
and hot-spot radioactive material is to be removed, there seems little use in applying Compton
imaging to decontamination wastes generated from restoration efforts.
Similarly, Nuvia also currently deploys by contract gamma spectrometry-based excavated
materials/waste assay systems (Nfuvia. 2019). With a claimed 350 tons of material per day for
scanning and segregation, the Gamma Excavation Monitor (GEM) is a battery-operated Csl
gross gamma counting system where excavator buckets are placed over the devices to start the
counting sequence (Figure 3-15). The High-Resolution Assay Monitor (HiRAM) uses a High-
Resolution Gamma Spectrometer (HRGS) mounted on a turntable on a flatbed trailer for soil or
waste loaded into bags. Count times as little as 15 minutes for 1 m3 bags of rubble or soil are
claimed. Again, the lack of a for-purchase domestic supplier presents an opportunity to further
developwaste screening equipment and technologies.
Controller
Pallet & Load c
Detector
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Figure 3-15. Nuvia's Gamma Excavation Monitor (GEM) and High-Resolution Assay Monitor
(HiRAM) systems for measuring radioactivity in removed waste (Nuvia. 2019)
3.6 Plastic Scintillation Fibers
Plastic scintillation fibers (PSF) have been tested in Japan following the Fukushima Daiichi NPP
accident. Plastic scintillation fibers were developed and initially tested over 5 decades ago (e.g.,
Reynolds and Condon. 1957; Jopson, Wright, and Mark. 1960; and Chupp and Forrest. 1966)
largely to detect neutrons, track charged particles and characterize particle beams. Additional
information on the theory and historical development of PSF detectors is presented in Sutton and
Gorman (2016a).
Plastic scintillation fibers have several key advantageous features, including (Oka. 1998; Park
and Kim. 2004; Sanada 2015):
•	Long length for wide coverage (e.g., -20 m for urban area application)
•	Flexible (durable)
•	Conforms to surface shape (provides improved geometry)
•	High water resistance (for underwater or all-weather applications)
•	Can be bundled to improve detection
•	Serves as both scintillator and light transmitter
•	Requires no electric power for the sensor portion (less susceptible in harsh environments)
•	Relatively inexpensive to manufacture
•	Not influenced by magnetic fields (although photo-multiplier tubes are)
In 2012, Hitachi-GE Nuclear Energy developed a plastic scintillation fiber that operates for four
hours continuously with a rechargeable battery that can measure air dose rates as far as 20 m in a
few seconds.4 The work published in 2014 (Gamo et al .) provided examples of using 1, 7 and 12
PSF bundles to measure contamination along a roadway gutter, and potential applications on a
building wall, a tree, a pond and attached to a vehicle to survey roads. The technology is paired
with GE's SOPHIDA and D-phod Viewer software with mesh sizes of 10 m and 1 m
respectively.
4 ttp://enfomiable.com/2012/05/ge-developing-fiber-optic-gamma-radiation-dose-rate-detection-and-measurement-
system/
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IHI Corporation attached PSF to a turf stripper to measure and remove contaminated soil,
demonstrating the capability in Okuma Town and Soma City, Japan. The technique provides 2-
dimensional mapping, evaluation of depth profile, turf removal, reduction in soil or turf waste
volume and reduction in work hours (MOE.: ). The application of PSF on vehicles should
be investigated in U.S. studies, particularly on those vehicles capable of performing
decontamination or stabilization of contamination on surfaces.
Recent work by Sanada and colleagues at JAEA has investigated the application of PSF to
various contaminated areas resulting from the Fukushima Daiichi NPP. A 19-fiber, 12-m long
PSF array was placed across a field, straddling the boundary between contaminated and
decontaminated land. The results showed a clear delineation between the two areas (Todani.
2011). At the same time, measurements of radiation dose rates were made in Minamisoma City
and Date City, Japan, using PSF and identifying where high doses were collocated with cracks in
asphalt pavement (IAEA. 2011). Similarly, a 20-m long bundle of 10 polystyrene 1-mni-
di am eter PSFs with poly(methyl methacrylate) (PMMA) cladding was manually moved along
outdoor surfaces at schools at a rate of 0.1 m/s (equivalent to 0.2 mph), allowing the 2-
dimensional mapping of 137Cs before and after decontamination (Torii and Sanada. 2013). In the
same paper, the technique was also applied to the front of a construction vehicle (e.g., IHI CL45
compact track loader) and allowed the mapping of a 2,000-square meter (m2) area within one
hour.
Additional studies were documented using PSF to measure the contamination at the bottom of a
pond in Fukushima Prefecture using a 20-m submerged PSF bundle (IAEA. 2014a). JAEA
extended the PSF length to 50-m that was used to monitor leakage from contaminated water
tanks at the Fukushima Daiichi NPP (JAEA. 2014b and 2015a). Sanada et al. (2015) utilized
nineteen bundled 1-mm-diameter, 20 m-length Kuraray SCSF-3HF plastic scintillation fibers to
measure 137Cs in sediments below water in irrigation ponds that have collected falling rain in
Fukushima Prefecture. The results compared well with sediment cores taken after measurement
by PSF. Subsequent measurements taken after decontamination were integrated with GIS maps
to demonstrate monitoring of decontamination efficacy. Example JAEA applications are shown
in Figure 3-16 (reproduced from IAEA. 2015b). JAEA utilizes a system built by JREC Co.
Ltd., and the P-SCAN software to process data.
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Figure 3-16. JAEA Application of Plastic Scintillation Fibers in Post-Fukushima Surveys
(Reproduced from JAEA. 2015b). PSF equipment supplied by JREC (A); Application of PSF to
survey pond sediments (B); Application of PSF to survey forest soil (C); Application of PSF to
measure outdoor urban surfaces, e.g., school playground (D). Notes: PMT = photo-multiplier tube;
PC = personal computer
Further development of PSF fibers has recently been performed at LLNL (Sutton and Swanberg.
2017). The entire system is not commercially available but has been created from off-the-shelf
products and is designed to be smaller and more portable than the PSF systems demonstrated in
Japan by the JAEA and IHI Corporation. The LLNL PSF system utilizes a bundle of 7
scintillating fibers of various interchangeable lengths from 15 cm to 10 m in a heat-shrink
coating, two small photomultiplier tubes, a digital oscilloscope, a Raspberry Pi3 (single-board
computer with wireless LAN and Bluetooth connectivity), a handheld tablet for real-time view of
detector performance, and a rechargeable USB battery pack. Figure 3-17 shows the detector
components.
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Figure 3-17. LLNL Plastic Scintillation Fiber Detector Components. Scintillation fiber optic
bundle (a), digital oscilloscope (b), photomultiplier tubes connected by short fiber for
demonstration (c), handheld tablet (d), Raspberry Pi 3 (e), USB battery pack (f).
The system has been evaluated for spatial resolution, dose rate accuracy, minimum detectable
dose rate and underwater functionality. The LLNL PSF detector can see as low as 10
microroentgens per hour dose rates with a 10 second measurement. The system is insensitive to
gamma energies below about 150 keV due to the low light yield of the scintillator combined with
light loss over the length of the fiber. Performance for specific radionuclides tested include:
•	Barium-133 (320 keV) is clearly seen by the LLNL PSF detector, as are 137C.s (661 keV)
and Cobalt-60 (1173 and 1332 keV);
•	Cobalt-57 (122 keV) dose rates detected by the PSF detector is lower than the actual;
•	Americium-241 (60 keV) is not seen at all by the PSF detector.
The position resolution using FWHM is 0.5 m and the 10-m fiber bundle performs well with
minimal degradation compared to the 3-m bundle. Figure 3-18 shows a coiled 10-m 7-fiber
bundle that may be used for water infrastructure measurement/detection, or gantry or crane
application for surveying walls. Shorter fiber bundle lengths (e.g., 1 m or 3 m) are more
appropriate for attaching to vehicles to monitor roads, freeways or parking lots. Longer lengths
of fiber bundles required signal delays to maintain signal timing from one end of the detector to
the other.
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Figure 3-18. A coiled 10-meter 7-fiber PSF Bundle (with Heat-shrink Coating and Signal Delay) for
Water Infrastructure or Wall Surveys.
Examples of additional applications of PSF for monitoring contamination and remedi ation
progress are given in Sutton and Gorman (2016a). For monitoring decontamination progress
specifically, the following applications of PSF detectors are recommended:
•	Attachment of shorter length PSF detectors to vehicles, perpendicular to the direction of
travel, to survey roads, freeways, parking lots etc.
•	Attachment of longer length PSF detector across the surface of a building, possibly from
a gantry or crane.
•	Vertical emplacement of PSF fibers in contaminated subsurface systems to monitor
remediation and contaminant transport.
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4 Summary and Conclusions
A variety of equipment technologies and platforms exist for surveying contaminated areas and
monitoring the progress of decontamination/dose reduction activities to suit the survey area size,
terrain, and desired resolution. Handheld methods are very labor-intensive and cover only a
small surface area, whereas mobile detection (aerial or ground-based) can significantly speed up
the surveying of surfaces. Aerial mapping of contamination can cover large areas quickly and is
not dependent on road/terrain but lacks the same precision of ground-based surveys. Conversely,
ground-based surveys can be slow to perform and are limited by access for a given terrain,
although personnel-based surveying using backpack-style meters can help. Compton imaging
cameras, ground-based mobile surveys using scintillation detectors, and plastic scintillation
fibers can provide area maps of contamination.
Portions of higher radiological contamination were observed in an area surrounding several
buildings near the Fukushima NPP. If these measurements are reflective of sub-surface
contamination (e.g., RDD using unirradiated oxide fuel particulates), proper site survey before
decontamination and proper assessment methods for decontamination progress could
significantly reduce overall cost and time for decontamination, waste volume generated in a wide
area incident, and the time before unsupervised access can be permitted to the previously
contaminated site. More research is recommended to fully identify the circumstances and the
extent to which this advantage can be exploited.
Opportunities for future work include significant research in expanding the tools available for
radiological contamination surveying and monitoring. United States deployment of UAVs for
surveying and monitoring as well as detectors (e.g., plastic scintillation fibers) mounted on
decontamination and transportation vehicles are recommended, among other new technologies
emerging from Japan and in the U.S. that merit possible inclusion in domestic RDD or IND
response.
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5 References
Andersson, K.G., Roed, J., Eged, K., Kis, Z., Voigt, G., Meckbach, R. Oughton, D.H. Hunt, J.
Lee, R., Beresford, N.A. and Sandalls, F.J. (2003) Physical Countermeasures to Sustain
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Appendix A: Datasheets for Radiological Surveying Technologies
This section summarizes the six established radiologically contaminated site surveying and
monitoring equipment classes found in the available published technical literature that have been
used in actual radiological incident responses.
While significant overlap in the literature was found for many equipment classes, some other
cases had little to no overlap leading to "gaps" in the desired information (i.e., "N/A" or "no data
available"). Reported information were found at times to vary significantly with little
explanation, and some terminology may be a bit unclear due to the citation of foreign literature
sources. The numbers are listed as reported in the reviewed literature, and foreign currencies
were converted using Internal Revenue Service 2018 yearly average exchange rates: 110 JPY =
1 USD, 0.85 EUR = 1 USD (IRS. ). No inflation adjustments were attempted for historical
costs.
Equipment specifics in the table clarify which characteristics/data belong to which equipment
sub-categories, especially where differences are significant and/or may be important in decision-
making.
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A.1 Ground Vehicle Radiation Monitoring/Surveying
Description
GPS-equipped SUV or motorcycle mounted detection systems can
measure both low and high dose rate ranges, specifically 0.01 to 10 micro-
Sieverts per hour (piSv/hr) using a shielded thallium-doped sodium iodide
[Nal(TI)] scintillation detector, and up to 100,000 piSv/hr using semi-
conductor detector technology. Dust and gas sampling can measure
alpha- and beta-emitting radionuclides in airborne particles and capture
radioactive iodine. Since vehicle-borne systems can more easily monitor
at one spot longer, traverse more slowly and get closer to the
contamination than air-borne systems, such systems generally provide
improved detection sensitivities and greater resolution of changing
contamination.
Instruments can also include gamma compensating gas flow proportional
counters (Argon-10% methane), Lithium-6 scintillating neutron detectors,
Geiger-Muller tubes, LaBr3:Ce detectors, and plastic scintillation fibers
mounted on the vehicle. Plastic scintillation fibers can also be used
underwater to survey sediments. Sophisticated systems can integrate
radioisotope identification, GPS data, and wireless connections to provide
real-time mapping. Some can be temperature limited (e.g., -20 to 50°C,
FlexSpec).
Plastic Scintillation Fiber equipped boat can survey underwater sediment
mapping efficiently relative to core samples.
Environmental, Safety,
and Health (ES&H) Issues
Car-borne methods may not be safe near the hotspots in the reactor core
and its surrounding region for the personnel operating the vehicle.
Cost
Capital cost:
$175,000 -1,200,000 (2013)
Operating cost:
N/A
Throughput
Variable depending on the detector type, speed, contamination level,
0.056 |a,Sv/h to 0.1 |a,Sv/h measured at a source-detector distance of 1 m
with integration time varying from 3 to 180 s.
Technology Current
State
Ground vehicle system can serve as a mobile lab to assist analysis of soil
sample. New systems are equipped with built-in computer attached to
the radiation detector incorporating a complicated correction factor.
References
IAEA, 1989.
Sutton, 2016b.
DHS, 2013.
Pradeep Kumar, (2020).
Innovative American Technology Inc.
Bubble Technology Inc.
FLIR Radiation Inc.
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A.2 Airborne Radiation Surveying
Description
Helicopter- or fixed-wing aircraft-mounted radiation sensors (such as
sodium iodide or germanium) that measure total gamma count rate. The
counts, positional information (e.g., flight path, GPS positioning,
microwave location), and imagery are used to generate a map of radiation
over an area. Helicopters may be used for higher precision low-altitude
work and airborne measurements may be cross-checked with ground-
level measurements. Some can be operating temperature limited (e.g., -
20°C to 50°C, upgradable to -40°C to 50°C, SPIR-ldent).
Efficacy (dose reduction)
For many years remote gamma sensing from aircraft has been an effective
way of rapidly locating, monitoring and mapping gamma activity on the
ground. Gamma survey data overlaid on aerial photographs indicate
the location of the contamination very accurately.
ES&H
N/A
Cost
Capital cost:
$285,000 -1,200,000 (2013)
Operating cost:
N/A
Throughput
Helicopters: 130 - 185 km/hr helicopter speed with 600 m wide scan
width (at nominal 300 m altitude).
Airplanes: 130 - 185 km/hr helicopter speed with 600 m wide scan width
(at nominal 300 m altitude).
Manned helicopters and fixed wing aircrafts can cover >100 km2 survey
areas.
Technology Current
Method can take gamma counts and convert to 134Cs- & 137Cs- deposited
State
radioactivity maps, as well as radiation dose rates (piSv/hr)
References
Asano,2013.
IAEA, 1989.
Sutton, 2016b.
DHS, 2013.
Pradeep Kumar, (2020).
Mirion Technologies Inc.
FLIR Radiation Inc.
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A.3 Unmanned Aerial Vehicle Radiation Surveying
Description
An unmanned aerial vehicle (e.g., "drone"), helicopter- or fixed-wing
aircraft with mounted radiation sensors (such as cesium iodide or
lanthanum bromide) that measures total gamma count rate and/or micro-
Sieverts/hour and transmits the data (radiation dose, GPS position) via
antenna to a ground-base. Small UAVs/helicopters can focus on smaller
or inaccessible locations (under tree lines and bridges, between buildings,
unwalkable terrain, etc.) where higher mapping resolution is desired, as
well as mapping contamination on buildings (e.g., high-rise walls, roof) to
minimize decontamination costs.
Efficacy (Dose
Reduction)
N/A
ES&H Issues
N/A
Cost
Capital cost:
~$50,000 (including mandatory training, 2018)
Operating cost:
N/A
Throughput
Operating altitudes for small UAVs are typically <10 m, ~50 m for
unmanned helicopters, and ~150 m for unmanned airplanes, allowing
survey areas from <1 km2, > 1 km2, and >100 km2, respectively.
Technology Current
State
UAVs have been flown within 3 km of Fukushima Daiichi NPP, and for river
channel contamination surveys; payload (1-90 kg), battery life (~2 hrs.)
References
Asano,2013.
Mivahara, 2015.
Sutton, 2016b.
Berkeley Nucleonics Corp.
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A.4 Hand-Held Gamma and Beta Detectors
Description
Used for ground verification of the measured activity, especially on
buildings and equipment. Gamma detectors are most commonly
thallium-doped sodium iodide [Nal(TI)], which has adequate resolution for
identifying most radioisotopes. Thallium-doped cesium iodide [Csl(TI)] has
poorer resolution than Nal(TI) but is less shock- and vibration-sensitive.
Cerium-doped lanthanum bromide (LaBr3:Ce) detectors have
approximately twice the resolution of Nal(TI) but are more costly. High-
purity germanium detectors are very high resolution but must be cooled
to liquid-nitrogen temperatures for several hours before being operable.
Detectable species include transuranics, activation products and fission
products. Total measured quantum flux can be recalculated into specific
and surface radioactivity.
One example of a beta detector is a portable battery-operated butane gas
proportional beta counter.
This method requires detailed protocols and parameters such as
measurement time and distance of instrument from surface. Surface
contamination only measurement requires well-trained personnel
(gamma); >10 kBq/m2 on surface (beta) required for detection; >1 kBq/m2
on surface (gamma) required for detection.
Target Contaminated
Surface Type
Building roofs and walls
Equipment
Soils
Efficacy
Experience in the United States Department of Energy (USDOE) remedial
action programs involving the cleanup of thousands of hectares indicates
that a hand-held sodium iodide detector, coupled with a rate meter, is an
effective tool for locating surface depositions of gamma emitting
radionuclides and identifying hot spots after completion of the remedial
action.
ES&H Issues
2 man-hours exposure/location (gamma)
0.08 man-hour exposure/location (3" x 3", 58 square centimeter or [cm2]
locations, gamma)
0.08 man-hours exposure/location (166 cm2 locations, beta)
Cost
Capital cost:
$4,100 -$35,300 (1995)
Operating cost:
0.01 - 0.25 man-day/location
Throughput
10 locations/hr (3" x 3" or 58 cm2 each, gamma)
10 locations/hr (166 cm2 each, beta)
0.050 |a,Sv/h to 1 |a,Sv/h measured at a source-detector distance of 1 m
with integration time varying from 900 to 1200 s.
Technology Current State
Low cost, rugged and mobile
References
IAEA, 1989.
DHS, 2013.
Roed,1995.
Pradeep Kumar, (2020).
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A.5 Gamma Cameras and Compton Imaging
Description
Standoff gamma cameras when paired with visual images can locate areas
of elevated contamination, particularly for those with little training in
gamma measurements.
Compton imaging cameras permit both the identification of surface
contamination and a measure of decontamination progress. One mobile
system uses detectors in two vehicles (airplanes, trucks, trailers, or small
marine vessels).
Cost
Capital cost:
$60,000-1,200,000
Operating cost:
N/A
Throughput
Gamma cameras: After a 30-minute count time, identified a 20 piSv/h hot-
spot in a parking lot and another 30 piSv/h hot-spot 10 m from the
camera.
Technology Current
N/A
State

References
Sutton, 2016b.
DHS, 2013.
FLIR Radiation Inc.
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A.6 Manual Soil Sampling
Description
Manual collection of samples over a wide region, with samples analyzed in
a laboratory using detectors (e.g., germanium) for radionuclides. Wider
areas can be estimated when combined with models (e.g., WSPEEDI)
using meteorological data. Typically used to "calibrate" vehicle-derived
wider-area radiological measurements. This methods requires intensive
manpower and resource.
Efficacy
N/A
ES&H Issues
N/A
Cost
N/A
Implementation (Lead)
Time
0.1 -18 days analysis times plus samples delivery time (depending on
method and elements being analyzed - most in the ~l-5-day range for
beta & gamma emitters)
Throughput
N/A
Technology Current
State
N/A
References
Asano,2013.
Feltcorn, 2006.
Mivahara, 2015.
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vvEPA
United States
Environmental Protection
Agency
PRESORTED STANDARD
POSTAGE & FEES PAID
EPA
PERMIT NO. G-35
Office of Research and Development (8101R)
Washington, DC 20460
Official Business
Penalty for Private Use
$300
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