ASTM C1112-99
(Guide)Standard Guide for Application of Radiation Monitors to the Control and Physical Security of Special Nuclear Material
Standard Guide for Application of Radiation Monitors to the Control and Physical Security of Special Nuclear Material
SCOPE
1.1 This guide briefly describes the state-of-the-art of radiation monitors for detecting special nuclear material (SNM) (see 3.1.11) in order to establish the context in which to write performance standards for the monitors. This guide extracts information from technical documentation to provide information for selecting, calibrating, testing, and operating such radiation monitors when they are used for the control and protection of SNM. This guide offers an unobtrusive means of searching pedestrians, packages, and motor vehicles for concealed SNM as one part of a nuclear material control or security plan for nuclear materials. The radiation monitors can provide an efficient, sensitive, and reliable means of detecting the theft of small quantities of SNM while maintaining a low likelihood of nuisance alarms.
1.2 Dependable operation of SNM radiation monitors rests on selecting appropriate monitors for the task, operating them in a hospitable environment, and conducting an effective program to test, calibrate, and maintain them. Effective operation also requires training in the use of monitors for the security inspectors who attend them. Training is particularly important for hand-held monitoring where the inspector plays an important role in the search by scanning the instrument over pedestrians and packages or throughout a motor vehicle.
1.3 SNM radiation monitors are commercially available in three forms:
1.3.1 Small Hand-Held Monitors- These monitors may be used by an inspector to manually search pedestrians and vehicles that stop for inspection.
1.3.2 Automatic Pedestrian Monitors -These monitors are doorway or portal monitors that search pedestrians in motion as they pass between radiation detectors, or wait-in monitoring booths that make extended measurements to search pedestrians while they stop to obtain exit clearance.
1.3.3 Automatic Vehicle Monitors -These monitors are portals that monitor vehicles as they pass between radiation detectors, or vehicle monitoring stations that make extended measurements to search vehicles while they stop to obtain exit clearance.
1.4 Guidance for applying SNM monitors is available as Atomic Energy Commission/Nuclear Regulatory Commission (AEC/NRC) regulatory guides, AEC/ERDA/DOE performance standards, and more recently as handbooks and applications guides published by national laboratories under DOE sponsorship. This broad information base covering the pertinent physics, engineering practice, and equipment available for monitoring has had no automatic mechanism for periodic review and revision. This ASTM series of guides and standards will consolidate the information in a form that is reexamined and updated on a fixed schedule.
1.5 Up-to-date information on monitoring allows both nuclear facilities and regulatory agencies to be aware of the current range of monitoring alternatives. Up-to-date information also allows manufacturers to be aware of the current goals of facilities and regulators, for example, to obtain particular sensitivities at a low nuisance alarm rate with instrumentation that is dependable and easy to maintain.
1.6 This guide updates and expands the scope of NRC regulatory guides and AEC/ERDA/DOE SNM monitor performance standards using the listed publications as a technical basis.
1.7 The values stated in SI units are to be regarded as the standard.
1.8 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation:C1112–99
Standard Guide for
Application of Radiation Monitors to the Control and
Physical Security of Special Nuclear Material
This standard is issued under the fixed designation C 1112; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 1.3.3 Automatic Vehicle Monitors—These monitors are por-
tals that monitor vehicles as they pass between radiation
1.1 This guide briefly describes the state-of-the-art of radia-
detectors, or vehicle monitoring stations that make extended
tionmonitorsfordetectingspecialnuclearmaterial(SNM)(see
measurements to search vehicles while they stop to obtain exit
3.1.11) in order to establish the context in which to write
clearance.
performance standards for the monitors. This guide extracts
1.4 Guidance for applying SNM monitors is available as
information from technical documentation to provide informa-
Atomic Energy Commission/Nuclear Regulatory Commission
tion for selecting, calibrating, testing, and operating such
(AEC/NRC)regulatoryguides,AEC/ERDA/DOEperformance
radiation monitors when they are used for the control and
standards, and more recently as handbooks and applications
protection of SNM. This guide offers an unobtrusive means of
guides published by national laboratories under DOE sponsor-
searching pedestrians, packages, and motor vehicles for con-
ship. This broad information base covering the pertinent
cealed SNM as one part of a nuclear material control or
physics, engineering practice, and equipment available for
security plan for nuclear materials. The radiation monitors can
monitoring has had no automatic mechanism for periodic
provide an efficient, sensitive, and reliable means of detecting
review and revision.ThisASTM series of guides and standards
the theft of small quantities of SNM while maintaining a low
will consolidate the information in a form that is reexamined
likelihood of nuisance alarms.
and updated on a fixed schedule.
1.2 Dependable operation of SNM radiation monitors rests
1.5 Up-to-date information on monitoring allows both
on selecting appropriate monitors for the task, operating them
nuclear facilities and regulatory agencies to be aware of the
in a hospitable environment, and conducting an effective
current range of monitoring alternatives. Up-to-date informa-
program to test, calibrate, and maintain them. Effective opera-
tion also allows manufacturers to be aware of the current goals
tionalsorequirestrainingintheuseofmonitorsforthesecurity
of facilities and regulators, for example, to obtain particular
inspectors who attend them. Training is particularly important
sensitivities at a low nuisance alarm rate with instrumentation
for hand-held monitoring where the inspector plays an impor-
that is dependable and easy to maintain.
tant role in the search by scanning the instrument over
1.6 This guide updates and expands the scope of NRC
pedestrians and packages or throughout a motor vehicle.
regulatory guides andAEC/ERDA/DOE SNM monitor perfor-
1.3 SNM radiation monitors are commercially available in
mance standards using the listed publications as a technical
three forms:
basis.
1.3.1 Small Hand-Held Monitors—These monitors may be
1.7 The values stated in SI units are to be regarded as the
used by an inspector to manually search pedestrians and
standard.
vehicles that stop for inspection.
1.8 This standard may involve hazardous materials, opera-
1.3.2 Automatic Pedestrian Monitors—These monitors are
tions, and equipment. This standard does not purport to
doorwayorportalmonitorsthatsearchpedestriansinmotionas
address all of the safety problems associated with its use. It is
they pass between radiation detectors, or wait-in monitoring
the responsibility of the user of this standard to establish
booths that make extended measurements to search pedestrians
appropriate safety and health practices and determine the
while they stop to obtain exit clearance.
applicability of regulatory limitations prior to use.
This guide is under the jurisdiction ofASTM Committee C-26 on Nuclear Fuel
Cycleand is the direct responsibility of Subcommittee C26.12 on Safeguard
Applications.
Current edition approved June 10, 1999. Published July 1999. Originally Copiesofout-of-printreferencesmaybeavailablefromGroupNIS6,MS-J562,
published as C 1112 – 88. Last previous edition C 1112 – 93. Los Alamos National Laboratory, Los Alamos, NM 87545.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C 1112
2. Referenced Documents approximate testing with a particular plutonium test source.
Gas lantern mantles containing thorium are radioactive and
2.1 ASTM Standards:
3 sometimes are used to test continuity in hand-held monitors.
C 859 Terminology Relating to Nuclear Materials
3.1.2 detection sensitivity—specifiedintermsofthemassof
C 993 Guide for In-Plant Performance Evaluation of Auto-
SNM that will be detected 50 % or more of the time when
matic Pedestrian SNM Monitors
carried through the monitor in a specified fashion. This
C 1169 Guide for Laboratory Evaluation of Automatic Pe-
convenient definition greatly simplifies SNM monitor perfor-
destrian SNM Monitor Performance
mancetestingandmakesitpossibletoreadilyverifysensitivity
C 1189 Guide to Procedures for Calibrating Automatic
byperforminganexperimentthatmimicsthemonitor’snormal
Pedestrian SNM Monitors
use. The related masses that would be detected 95 % or 99 %
C 1236 Guide for In-Plant Performance Evaluation of Au-
of the time can be estimated from the 50 % mass but would be
tomatic Vehicle SNM Monitors
impractical to determine with high confidence by themselves.
C 1237 Guide for In-Plant Performance Evaluation of
Experiments conducted to determine or verify sensitivity must
Hand-Held SNM Monitors
be thorough enough to have an upper 95 % confidence coeffi-
2.2 Code of Federal Regulations:
cient so that repeating the experiment will probably give the
Title 10, Part 73, Physical Protection of Plants and Materi-
same result.
als
3.1.3 monitoring—the process of detecting increased radia-
2.3 AEC/NRC Regulatory Guides:
5.27 Special Nuclear Material Monitors, June 1974 tion intensity by making one or more measurements of the
intensity in the vicinity of a pedestrian or motor vehicle for
5.7 Control of Personnel Access to Protected Areas, Vital
Areas, and Material Access Areas, May 1980 comparison with an alarm threshold derived from the expected
background radiation intensity.
2.4 AEC/ERDA/DOE SNM Monitor Standards:
Personnel Doorway Monitor Standards, January 1974
3.1.4 NaI(Tl) detector—an inorganic sodium iodide (thal-
Standards for Hand-Held SNM Detection Instruments for lium activated) (NaI(Tl)) scintillation detector that has inher-
Personnel, Package, and Vehicle Search, April 1974
ently good gamma-ray sensitivity but poor neutron response.
2.5 NRC NUREG and NUREG/CR Reports:
3.1.5 nuisance alarms—an alarm not caused by SNM but
NUREG 1321, Testing Standards for Physical Security
by one of a number of other causes. For example, the statistical
Systems at Category I Fuel Cycle Facilities, October
variation in the measurement process, natural or process-
induced background intensity increases, or the presence of
NUREG 1329, Entry/Exit Control at Fuel Fabrication Fa-
non-SNM radiation emitters, among other things, may increase
cilities Using or Possessing Formula Quantities of Strate-
a monitor’s measurement result by enough to cause an alarm.
gic Special Nuclear Material, November 1985
Nuisance alarms from statistical variation, by design, are the
NUREG/CR 5899 (SAND 92-1339), Entry/Exit Control
only ones present during testing and are the ones of concern in
Components for Physical Protection Systems, 1992
designing and evaluating SNM monitors. These statistical
alarms are expressed in terms of alarms per comparison (test)
3. Terminology
or, more importantly, alarms per passage, which may include a
3.1 Definitions of Terms Specific to This Standard:
numberofcomparisons.Amonitor’ssusceptibilitytostatistical
3.1.1 alternative test sources—there are no other radioac-
alarms and its detection sensitivity are directly related.
tive isotopes that individually or together can duplicate the
3.1.6 passthrough monitor—a radiation monitor that allows
radioactive emissions of SNM. Hence, performance testing in
free passage as it makes monitoring measurements and does
a laboratory environment will use only SNM test sources.
notrequirethepersonorvehiclebeingmonitoredtostopunless
Operational testing at the recommended three-month interval
it alarms.
can most often use SNM test sources, although sometimes a
3.1.7 plastic scintillation detector—a solid organic scintil-
more readily available equivalent-intensity highly enriched
lator that responds to both gamma rays and energetic neutrons
uranium (HEU) source may be used in place of a very
through scattering interactions between the incident radiation
expensive and hard to obtain plutonium source. The more
and electrons or protons in the scintillator.
frequent daily or weekly operational testing will often substi-
3.1.8 radiation detector—( 1) a detector consisting of a
tute alternative isotopic sources. Often these are continuity
scintillating material and attached photomultiplier tube that
tests that can use the cesium-137 ( Cs) sources that are on
produces light from neutron or gamma-ray interactions and
handforpulseheightcalibration.Alsobarium-133( Ba)may
converts the light to electrical signals. (2) a neutron propor-
be used when a gamma-ray spectrum similar to plutonium is
tional counter containing a converter gas to produce electrical
needed to make a daily or weekly test that must roughly
signals from neutron interactions.
3.1.9 standard SNM performance test source—a metallic
3 sphereorcubeofSNMhavingmaximumself-attenuationofits
Annual Book of ASTM Standards, Vol 12.01.
emitted radiation and an isotopic composition to minimize that
Available from the Superintendent of Documents, U.S. Government Printing
Office, Washington, DC 20402.
emission. Such minimum radioactive emission sources as
Available from the U.S. Nuclear Regulatory Commission, Washington,
described in 3.1.9.1 and 3.1.9.2 allow testing with the worst-
DC 20555.
case forms of SNM. As a result of worst-case testing, routine
Chapter 4, Entry-Control Systems Handbook, SAND77-1033, Sandia National
Laboratories, Albuquerque, NM 87185. operation of a tested monitor in a plant achieves as good or
C 1112
better performance and the monitor will detect the same or 5. Types of SNM Monitors
smaller masses of process SNM.
5.1 Hand-Held Monitors—These small, battery-powered,
3.1.9.1 special nuclear material (SNM)—plutonium with an
computer-operated instruments (Fig. 1) measure ambient back-
isotopic content of at least 93 % plutonium-239 ( Pu) and
ground intensity (over8sorso)and then calculate an alarm
less than 6.5 % plutonium-240 ( Pu). The plutonium should
threshold on power-up or push-button command. Otherwise,
contain less than 0.5 % impurities. The form of the material
they continuously monitor, making short measurements (0.05 s
should be a metallic sphere or cube. The impact of americium-
long averaged over 0.4 s, for example) and then comparing the
241 ( Am), a plutonium decay product that will build up in
results to the alarm threshold. Hand-held monitor detectors
time and emit increasing amounts of 60-keV gamma radiation,
may be gamma-ray sensitive NaI(Tl) detectors or, more com-
must be minimized by including a cadmium filter 0.04 to
monly, plastic scintillation detectors that sense both gamma
0.08-cm thick as part of the source encapsulation. Protective
rays and neutrons (1-3). The operator of a hand-held monitor
encapsulationshouldbeinasmanylayersaslocalrulesrequire
scans (at about 0.5 m/s) the instrument over every surface of a
of a material such as aluminum (#0.32-cm thickness) or thin
pedestrian or vehicle, coming within 5 to 15 cm (2 to 6 in.) of
(#0.16-cm thickness) stainless steel or nickel that minimize
all possible locations for SNM (4).
unnecessary radiation absorption.
5.1.1 Frequent or continuous alarms in a particular region
3.1.9.2 standard uranium test source—highly enriched ura-
are clues that inform the operator of the presence and location
nium (HEU) containing at least 93 % uranium-235 ( U) and
of SNM. Occasional alarms from statistical variation in count-
less than 0.25 % impurities.The form of the material should be
ingdonotdetractfromsearchingsoaverylowalarmthreshold
a metallic sphere or cube. Encapsulation should be thin plastic
or thin aluminum (#0.32-cm thickness) to minimize unneces-
sary radiation absorption in the encapsulation.
The boldface numbers in parentheses refer to the list of references at the end of
3.1.10 special nuclear material (SNM)—plutonium of any
this guide.
isotopic composition, U, or enriched uranium as defined in
Terminology C 859. This is the term normally used to describe
monitors designed for monitoring SNM or strategic SNM,
which is plutonium, uranium-233, and uranium enriched to
20 % or more in the U isotope.
3.1.11 special nuclear material (SNM) monitor— a radia-
tiondetectionsystemthatmeasuresambientradiationintensity,
determines an alarm threshold from the result, and then when
it is monitoring, alarms if that threshold is exceeded.
3.1.12 wait-in monitor—a radiation monitor in which the
person or vehicle being monitored is required to stop and
remain stationary during monitoring measurement.
4. Significance and Use
4.1 SNM monitors are an efficient and sensitive means of
unobtrusively (without a body search) meeting the require-
ments of 10 CFR (Code of Federal Regulations) Part 73 or
DOE Order 5632.4 (May 1986) that individuals exiting nuclear
material access areas (MAAs) be searched for concealed SNM.
The monitors sense radiation emitted by SNM, which is an
excellent but otherwise imperceptible clue to the presence of
the material. Because the monitors operate in a natural radia-
tion environment and must detect small intensity increases as
clues, the monitors must be well designed and maintained to
operate without unnecessary nuisance alarms.
4.2 This guide provides information on different types of
monitors for searching pedestrians and vehicles. Each monitor
has an inherent sensitivity at a particular nuisance alarm rate
that must be low enough to maintain the monitor’s credibility.
Sensitiv
...
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