ASTM C1207-10(2018)
(Test Method)Standard Test Method for Nondestructive Assay of Plutonium in Scrap and Waste by Passive Neutron Coincidence Counting
Standard Test Method for Nondestructive Assay of Plutonium in Scrap and Waste by Passive Neutron Coincidence Counting
SIGNIFICANCE AND USE
5.1 This test method is useful for determining the plutonium content of scrap and waste in containers ranging from small cans with volumes of the order of a mL to crates and boxes of several thousand liters in volume. A common application would be to 208-L (55-gal) drums. Total Pu content ranges from 10 mg to 6 kg (1). The upper limit may be restricted depending on specific matrix, calibration material, criticality safety, or counting equipment considerations.
5.2 This test method is applicable for U.S. Department of Energy shipper/receiver confirmatory measurements (9), nuclear material diversion detection, and International Atomic Energy Agency attributes measurements (10).
5.3 This test method should be used in conjunction with a scrap and waste management plan that segregates scrap and waste assay items into material categories according to some or all of the following criteria: bulk density, the chemical forms of the plutonium and the matrix, americium to plutonium isotopic ratio, and hydrogen content. Packaging for each category should be uniform with respect to size, shape, and composition of the container. Each material category might require calibration standards and may have different Pu mass limits.
5.4 Bias in passive neutron coincidence measurements is related to item size and density, the homogeneity and composition of the matrix, and the quantity and distribution of the nuclear material. The precision of the measurement results is related to the quantity of nuclear material, the (α,n) reaction rate, and the count time of the measurement.
5.4.1 For both benign matrix and matrix specific measurements, the method assumes the calibration reference materials match the items to be measured with respect to the homogeneity and composition of the matrix, the neutron moderator and absorber content, and the quantity of nuclear material, to the extent they affect the measurement.
5.4.2 Measurements of smaller containers containing scrap and waste a...
SCOPE
1.1 This test method describes the nondestructive assay of scrap or waste for plutonium content using passive thermal-neutron coincidence counting. This test method provides rapid results and can be applied to a variety of carefully sorted materials in containers as large as several thousand liters in volume. The test method applies to measurements of 238Pu, 240Pu, and 242Pu and has been used to assay items whose total plutonium content ranges from 10 mg to 6 kg (1) .2
1.2 This test method requires knowledge of the relative abundances of the Pu isotopes to determine the total Pu mass (Test Method C1030).
1.3 This test method may not be applicable to the assay of scrap or waste containing other spontaneously fissioning nuclides.
1.3.1 This test method may give biased results for measurements of containers that include large amounts of hydrogenous materials.
1.3.2 The techniques described in this test method have been applied to materials other than scrap and waste (2, 3).
1.4 This test method assumes the use of shift-register-based coincidence technology (4).
1.5 Several other techniques that are often encountered in association with passive neutron coincidence counting exist. These include neutron multiplicity counting (5, 6, Test Method C1500), add-a-source analysis for matrix correction (7), flux probes also for matrix compensation, cosmic-ray rejection (8) to improve precision close to the detection limit, and alternative data collection electronics such as list mode data acquisition. Passive neutron coincidence counting may also be combined with certain active interrogation schemes as in Test Methods C1316 and C1493. Discussions of these established techniques are not included in this method.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, an...
General Information
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Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: C1207 − 10 (Reapproved 2018)
Standard Test Method for
Nondestructive Assay of Plutonium in Scrap and Waste by
Passive Neutron Coincidence Counting
This standard is issued under the fixed designation C1207; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 1.6 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This test method describes the nondestructive assay of
responsibility of the user of this standard to establish appro-
scrap or waste for plutonium content using passive thermal-
priate safety, health, and environmental practices and deter-
neutron coincidence counting. This test method provides rapid
mine the applicability of regulatory limitations prior to use.
results and can be applied to a variety of carefully sorted
1.7 This international standard was developed in accor-
materials in containers as large as several thousand liters in
238 dance with internationally recognized principles on standard-
volume. The test method applies to measurements of Pu,
240 242 ization established in the Decision on Principles for the
Pu, and Pu and has been used to assay items whose total
2 Development of International Standards, Guides and Recom-
plutonium content ranges from 10 mg to 6 kg (1).
mendations issued by the World Trade Organization Technical
1.2 This test method requires knowledge of the relative
Barriers to Trade (TBT) Committee.
abundances of the Pu isotopes to determine the total Pu mass
(Test Method C1030).
2. Referenced Documents
1.3 This test method may not be applicable to the assay of
2.1 ASTM Standards:
scrap or waste containing other spontaneously fissioning nu-
C986Guide for Developing Training Programs in the
clides.
Nuclear Fuel Cycle (Withdrawn 2001)
1.3.1 This test method may give biased results for measure-
C1009Guide for Establishing and Maintaining a Quality
mentsofcontainersthatincludelargeamountsofhydrogenous
AssuranceProgramforAnalyticalLaboratoriesWithinthe
materials.
Nuclear Industry
1.3.2 The techniques described in this test method have
C1030TestMethodforDeterminationofPlutoniumIsotopic
been applied to materials other than scrap and waste (2, 3).
Composition by Gamma-Ray Spectrometry
C1068Guide for Qualification of Measurement Methods by
1.4 This test method assumes the use of shift-register-based
a Laboratory Within the Nuclear Industry
coincidence technology (4).
C1128Guide for Preparation of Working Reference Materi-
1.5 Several other techniques that are often encountered in
als for Use in Analysis of Nuclear Fuel Cycle Materials
association with passive neutron coincidence counting exist.
C1133/C1133MTest Method for Nondestructive Assay of
Theseincludeneutronmultiplicitycounting(5, 6,TestMethod
SpecialNuclearMaterialinLow-DensityScrapandWaste
C1500), add-a-source analysis for matrix correction (7), flux
by Segmented Passive Gamma-Ray Scanning
probes also for matrix compensation, cosmic-ray rejection (8)
C1210Guide for Establishing a Measurement System Qual-
to improve precision close to the detection limit, and alterna-
ity Control Program for Analytical Chemistry Laborato-
tive data collection electronics such as list mode data acquisi-
ries Within the Nuclear Industry
tion. Passive neutron coincidence counting may also be com-
C1316Test Method for Nondestructive Assay of Nuclear
bined with certain active interrogation schemes as in Test
Material in Scrap and Waste by Passive-Active Neutron
Methods C1316 and C1493. Discussions of these established
Counting Using Cf Shuffler
techniques are not included in this method.
C1458Test Method for NondestructiveAssay of Plutonium,
Tritium and Am by Calorimetric Assay
This practice is under the jurisdiction of ASTM Committee C26 on Nuclear
Fuel Cycle and is the direct responsibility of Subcommittee C26.10 on Non
Destructive Assay. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved April 1, 2018. Published April 2018. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1991. Last previous edition approved in 2010 as C1207–10. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/C1207-10R18. the ASTM website.
2 4
Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof The last approved version of this historical standard is referenced on
this test method. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1207 − 10 (2018)
C1490GuidefortheSelection,TrainingandQualificationof cans with volumes of the order of a mLto crates and boxes of
Nondestructive Assay (NDA) Personnel several thousand liters in volume. A common application
C1493Test Method for Non-Destructive Assay of Nuclear would be to 208-L (55-gal) drums. Total Pu content ranges
Material in Waste by Passive and Active Neutron Count- from 10 mg to 6 kg (1). The upper limit may be restricted
ing Using a Differential Die-Away System (Withdrawn depending on specific matrix, calibration material, criticality
2018) safety, or counting equipment considerations.
C1500Test Method for Nondestructive Assay of Plutonium
5.2 This test method is applicable for U.S. Department of
by Passive Neutron Multiplicity Counting
Energy shipper/receiver confirmatory measurements (9),
C1592/C1592MGuide for Making Quality Nondestructive
nuclear material diversion detection, and InternationalAtomic
Assay Measurements (Withdrawn 2018)
Energy Agency attributes measurements (10).
C1673Terminology of C26.10 NondestructiveAssay Meth-
5.3 This test method should be used in conjunction with a
ods
scrap and waste management plan that segregates scrap and
2.2 ANSI Standards:
wasteassayitemsintomaterialcategoriesaccordingtosomeor
ANSI 15.20Guide to Calibrating Nondestructive Assay
allofthefollowingcriteria:bulkdensity,thechemicalformsof
Systems
theplutoniumandthematrix,americiumtoplutoniumisotopic
ANSI 15.36Nondestructive Assay Measurement Control
ratio, and hydrogen content. Packaging for each category
and Assurance
shouldbeuniformwithrespecttosize,shape,andcomposition
3. Terminology
of the container. Each material category might require calibra-
tion standards and may have different Pu mass limits.
3.1 Refer to Terminology C1673 for definitions used in this
test method.
5.4 Bias in passive neutron coincidence measurements is
related to item size and density, the homogeneity and compo-
4. Summary of Test Method
sition of the matrix, and the quantity and distribution of the
4.1 The even mass isotopes of Pu fission spontaneously. On
nuclear material. The precision of the measurement results is
the average, two or more prompt neutrons are emitted per
related to the quantity of nuclear material, the (α,n) reaction
fission event. The number of time correlated or coincident
rate, and the count time of the measurement.
neutrons detected by the instrument is related to the effective
5.4.1 For both benign matrix and matrix specific
240 240
mass of Pu, m , present in the time. The effective Pu
measurements, the method assumes the calibration reference
eff
mass is a weighted sum of the even mass isotopes of Pu in the
materials match the items to be measured with respect to the
assay item. The total Pu mass is determined from the known
homogeneity and composition of the matrix, the neutron
plutonium isotopic ratios and the measured quantity m .
eff moderator and absorber content, and the quantity of nuclear
material, to the extent they affect the measurement.
4.2 The shift register technology is intended to correct for
5.4.2 Measurements of smaller containers containing scrap
the effects of Accidental neutron coincidences which result
and waste are generally more accurate than measurements of
fromtheregistrationofneutronsinthecoincidencegatewhich
larger items.
are not correlated in time to the neutron which triggered the
5.4.3 It is recommended that where feasible measurements
inspection of the gate.
be made on items with homogeneous contents. Heterogeneity
4.3 Otherfactorswhichmayaffecttheassayareneutronself
inthedistributionofnuclearmaterial,neutronmoderators,and
multiplication, matrix components with large (α, n) reaction
neutron absorbers have the potential to cause biased results.
rates, neutron absorbers, or moderators. Corrections for these
5.5 The coincident neutron production rates measured by
effectsareoftennotpossiblefromthemeasurementdataalone,
this test method are related to the mass of the even number
consequently assay items are commonly sorted into material
isotopes of plutonium. If the relative abundances of these
categories or additional information is sometimes used.
isotopes are not accurately known, biases in the total Pu assay
4.4 Corrections are typically made for electronic deadtime
value will result.
and neutron background.
5.6 Typical count times are in the range of 300 to 3600 s.
4.5 Calibrations are typically based on measurements of
well documented and appropriate reference materials. Model- 5.7 Reliable results from the application of this method
require training of the personnel who package the scrap and
ing based on knowledge of the instrument design and the
physicalprinciplesofneutroninteractionsmayalsobeapplied. waste prior to measurement and of personnel who perform the
measurements. Training guidance is available from ANSI
4.6 This method includes measurement control tests to
15.20, Guides C986, C1009, C1068, and C1490.
verify reliable and stable performance of the instrument.
5. Significance and Use 6. Interferences
5.1 Thistestmethodisusefulfordeterminingtheplutonium 6.1 Conditions affecting measurement uncertainty include
content of scrap and waste in containers ranging from small
neutron background, moderators, multiplication, (α, n) rate,
absorbers,matrixandnuclearmaterialheterogeneity,andother
sources of coincident neutrons. It is usually not possible to
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036, http://www.ansi.org. detect these problems or to calculate corrections for these
C1207 − 10 (2018)
effects from the measurement data alone. Consequently, assay
itemsaresortedintomaterialcategoriesdefinedonthebasisof
these effects.
6.2 Neutronbackgroundlevelsfromexternalsourcesshould
be kept as low and as constant as practical. Corrections can be
made for the effects of high-neutron background levels, but
these will adversely affect measurement precision and detec-
tion limits.
6.3 Neutron moderation by low atomic mass materials will
not only increase thermal-neutron absorption effects, but will
also increase multiplication effects. Consequently, the mea-
sured neutron rates may be either smaller or larger than those
for a nonmoderating matrix. Hydrogenous matrices contribute
the most to this effect (11).
FIG. 1 A Cross-section View of a Typical Thermal-Neutron Coinci-
6.4 Both spontaneous and induced fissions produce coinci-
dence Counter
dent neutrons. The instrument, however, cannot distinguish
between them. Three factors that strongly affect the degree of
multiplication are the mass of fissile material, its density, and
its geometry. Increases in mass that are not accompanied by
7.1.2 Reproducible positioning of the item in the assay
changes in either density or geometry will result in predictable
chamber is important for obtaining the best accuracy. This
multiplication increases that can be incorporated into the
counting geometry should be maintained for the measurement
calibration function. Localized increases in nuclear material
of all reference materials and assay items. (See 11.7.)
density and/or changes in the geometry are likely to cause
7.1.3 A 0.4 mm to 1 mm thick cadmium liner (12) is often
unknown changes in multiplication and measurement bias.
installed on the inside surfaces of the counting chamber
surroundingtheassayitem.Thislinerwillreducethedie-away
6.5 Neutrons from (α, n) reactions are an interference bias
time, decrease multiplication inside the item from returning
source if they induce multiplication effects. In addition, (α,n)
neutrons and decrease the effects on the assay of neutron
neutronscanincreasetheAccidentalsratetherebyaffectingthe
absorbers inside the item. The liner will also decrease neutron
statistical precision of the assay which is based on the net
detection efficiency due to absorption of thermalized neutrons
coincidence rate.
and may increase the cosmic ray spallation background. The
6.6 Biases may result from non-uniformity in the source
final design may represent a compromise between multiple
distribution and heterogeneity in the matrix distribution.
conflicting influences.
6.7 Otherspontaneousfissionnuclides(forexample,curium
7.2 Shielding—The detector assembly is often surrounded
or californium) will increase the coincident neutron count
by cadmium and an additional layer of hydrogenous material
rates, causing an overestimation of the plutonium content.
(see Fig. 1). Approximately 100 mm of polyethylene can
reduce the neutron background in the assay chamber by
6.8 Cosmic rays, which are difficult to shield against, can
approximately a factor of 10 (13).
producecoincidentneutrons.Cosmicrayeffectsbecomelarger
for small quantities of Pu in the presence of large quantities of
7.3 Electronics—High-count-rate nuclear electronics pro-
relatively high atomic number materials, for example, iron or videastandardlogicpulsefromthe Heproportionalcounters.
lead are more prolific producers than celluloxic wastes (see
These pulses are processed by the shift-register coincidence
12.5). technology.
7.4 Data acquisition and reduction can be facilitated by
7. Apparatus
interfacing the instrument to a computer.
7.1 Counting Assembly—See Fig. 1.
8. Hazards
7.1.1 Theapparatususedinthistestmethodcanbeobtained
commercially. Specific applications may require customized 8.1 Safety Hazards—Consult qualified professionals as
design. The neutron detectors are usually He proportional needed.
counters embedded in polyethylene. The detection efficiency 8.1.1 Precautions should be taken to prevent inhalation,
for neutrons of fission energy is typically at least 15%. Larger ingestion, or the spread of Pu contamination during waste or
det
...
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