ASTM C1133/C1133M-10(2018)
(Test Method)Standard Test Method for Nondestructive Assay of Special Nuclear Material in Low-Density Scrap and Waste by Segmented Passive Gamma-Ray Scanning
Standard Test Method for Nondestructive Assay of Special Nuclear Material in Low-Density Scrap and Waste by Segmented Passive Gamma-Ray Scanning
SIGNIFICANCE AND USE
5.1 Segmented gamma-ray scanning provides a nondestructive means of measuring the nuclide content of scrap and waste where the specific nature of the matrix and the chemical form and relationship between the nuclide and matrix may be unknown.
5.2 The procedure can serve as a diagnostic tool that provides a vertical profile of transmission and nuclide concentration within the item.
5.3 Item preparation is generally limited to good waste/scrap segregation practices that produce relatively homogeneous items that are required for any successful waste/inventory management and assay scheme, regardless of the measurement method used. Also, process knowledge should be used, when available, as part of a waste management program to complement information on item parameters, container properties, and the appropriateness of calibration factors.
5.4 To obtain the lowest detection levels, a two-pass assay should be used. The two-pass assay also reduces problems related to potential interferences between transmission peaks and assay peaks. For items with higher activities, a single-pass assay may be used to increase throughput.
SCOPE
1.1 This test method covers the transmission-corrected nondestructive assay (NDA) of gamma-ray emitting special nuclear materials (SNMs), most commonly 235U, 239Pu, and 241Am, in low-density scrap or waste, packaged in cylindrical containers. The method can also be applied to NDA of other gamma-emitting nuclides including fission products. High-resolution gamma-ray spectroscopy is used to detect and measure the nuclides of interest and to measure and correct for gamma-ray attenuation in a series of horizontal segments (collimated gamma detector views) of the container. Corrections are also made for counting losses occasioned by signal processing limitations (1-3).2
1.2 There are currently several systems in use or under development for determining the attenuation corrections for NDA of radioisotopic materials (4-8). A related technique, tomographic gamma-ray scanning (TGS), is not included in this test method (9, 10, 11).
1.2.1 This test method will cover two implementations of the Segmented Gamma Scanning (SGS) procedure: (1) Isotope Specific (Mass) Calibration, the original SGS procedure, uses standards of known radionuclide masses to determine detector response in a mass versus corrected count rate calibration that applies only to those specific radionuclides for which it is calibrated, and (2) Efficiency Curve Calibration, an alternative method, typically uses non-SNM radionuclide sources to determine system detection efficiency vs. gamma energy and thereby calibrate for all gamma-emitting radionuclides of interest (12).
1.2.1.1 Efficiency Curve Calibration, over the energy range for which the efficiency is defined, has the advantage of providing calibration for many gamma-emitting nuclides for which half-life and gamma emission intensity data are available.
1.3 The assay technique may be applicable to loadings up to several hundred grams of nuclide in a 208-L [55-gal] drum, with more restricted ranges to be applicable depending on specific packaging and counting equipment considerations.
1.4 Measured transmission values must be available for use in calculation of segment-specific attenuation corrections at the energies of analysis.
1.5 A related method, SGS with calculated correction factors based on item content and density, is not included in this standard.
1.6 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.
1.7 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 esta...
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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: C1133/C1133M − 10 (Reapproved 2018)
Standard Test Method for
Nondestructive Assay of Special Nuclear Material in Low-
Density Scrap and Waste by Segmented Passive Gamma-
Ray Scanning
ThisstandardisissuedunderthefixeddesignationC1133/C1133M;thenumberimmediatelyfollowingthedesignationindicatestheyear
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 determine system detection efficiency vs. gamma energy and
thereby calibrate for all gamma-emitting radionuclides of
1.1 This test method covers the transmission-corrected non-
interest (12).
destructive assay (NDA) of gamma-ray emitting special
235 239 1.2.1.1 Efficiency Curve Calibration, over the energy range
nuclear materials (SNMs), most commonly U, Pu,
241 for which the efficiency is defined, has the advantage of
and Am, in low-density scrap or waste, packaged in cylin-
providing calibration for many gamma-emitting nuclides for
drical containers. The method can also be applied to NDA of
which half-life and gamma emission intensity data are avail-
other gamma-emitting nuclides including fission products.
able.
High-resolution gamma-ray spectroscopy is used to detect and
measure the nuclides of interest and to measure and correct for 1.3 Theassaytechniquemaybeapplicabletoloadingsupto
gamma-ray attenuation in a series of horizontal segments several hundred grams of nuclide in a 208-L [55-gal] drum,
(collimated gamma detector views) of the container. Correc- with more restricted ranges to be applicable depending on
tions are also made for counting losses occasioned by signal specific packaging and counting equipment considerations.
processing limitations (1-3).
1.4 Measured transmission values must be available for use
1.2 There are currently several systems in use or under incalculationofsegment-specificattenuationcorrectionsatthe
development for determining the attenuation corrections for energies of analysis.
NDA of radioisotopic materials (4-8). A related technique,
1.5 A related method, SGS with calculated correction fac-
tomographic gamma-ray scanning (TGS), is not included in
tors based on item content and density, is not included in this
this test method (9, 10, 11).
standard.
1.2.1 This test method will cover two implementations of
1.6 The values stated in either SI units or inch-pound units
theSegmentedGammaScanning(SGS)procedure:(1)Isotope
are to be regarded separately as standard. The values stated in
Specific (Mass) Calibration, the original SGS procedure, uses
each system may not be exact equivalents; therefore, each
standards of known radionuclide masses to determine detector
system shall be used independently of the other. Combining
response in a mass versus corrected count rate calibration that
values from the two systems may result in non-conformance
applies only to those specific radionuclides for which it is
with the standard.
calibrated, and (2) Efficiency Curve Calibration, an alternative
1.7 This standard does not purport to address all of the
method, typically uses non-SNM radionuclide sources to
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
ThistestmethodisunderthejurisdictionofASTMCommitteeC26onNuclear
priate safety, health, and environmental practices and deter-
Fuel Cycle and is the direct responsibility of Subcommittee C26.10 on Non
mine the applicability of regulatory limitations prior to use.
Destructive Assay.
Current edition approved April 1, 2018. Published April 2018. Originally
Specific precautionary statements are given in Section 10.
approved in 1996. Last previous edition approved in 2010 as C1133/C1133M–10.
1.8 This international standard was developed in accor-
DOI: 10.1520/C1133_C1133M-10R18.
dance with internationally recognized principles on standard-
Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof
this test method. ization established in the Decision on Principles for the
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1133/C1133M − 10 (2018)
Development of International Standards, Guides and Recom- rate-relatedlossesandattenuationbytheitem.Theappropriate
mendations issued by the World Trade Organization Technical mass or efficiency calibration then provides the relationship
Barriers to Trade (TBT) Committee. between observed gamma-ray intensity and nuclide content.
4.2 Either of two distinct calibration methods can be used:
2. Referenced Documents
4.2.1 Isotope Specific Calibration provides assay results for
2.1 ASTM Standards:
only those radionuclides for which the SGS is specifically
C1030TestMethodforDeterminationofPlutoniumIsotopic
calibrated.Calibrationisperformedusingstandardscontaining
Composition by Gamma-Ray Spectrometry
the radionuclides to be assayed.
C1128Guide for Preparation of Working Reference Materi-
4.2.2 Effıciency Curve Calibration entails determination of
als for Use in Analysis of Nuclear Fuel Cycle Materials
the system detection efficiency as a function of gamma ray
C1156Guide for Establishing Calibration for a Measure-
energy. Analysis of assay data consists of using the energy of
ment Method Used toAnalyze Nuclear Fuel Cycle Mate-
a peak to infer the emitting radionuclide, and then calculating
rials
theradionuclidemassfromthespecificactivityandthegamma
C1207Test Method for Nondestructive Assay of Plutonium
emission intensity of the radionuclide, and the corrected count
in Scrap and Waste by Passive Neutron Coincidence
rate and detector efficiency at the peak energy.
Counting
4.3 The assay item is rotated about its vertical axis and
C1210Guide for Establishing a Measurement System Qual-
scanned segment by segment along that axis, thereby reducing
ity Control Program for Analytical Chemistry Laborato-
the effects of nonuniformity in both matrix density and nuclide
ries Within the Nuclear Industry
distribution (see Fig. 1).
C1215Guide for Preparing and Interpreting Precision and
Bias Statements in Test Method Standards Used in the 4.4 Count rate-dependent losses from pulse pile-up and
Nuclear Industry
analyzer dead time are corrected for by electronic modules, a
C1316Test Method for Nondestructive Assay of Nuclear radioactive source, a pulser, or a combination of these.
Material in Scrap and Waste by Passive-Active Neutron
4.5 The average linear attenuation coefficient of each hori-
Counting Using Cf Shuffler
zontalsegmentiscalculatedbymeasurementofthetransmitted
C1458Test Method for NondestructiveAssay of Plutonium,
intensity of an appropriate external gamma-ray source. The
Tritium and Am by Calorimetric Assay
sourceismounteddirectlyoppositethegamma-raydetector,on
C1490GuidefortheSelection,TrainingandQualificationof
the far side of the assay item (see Fig. 1).
Nondestructive Assay (NDA) Personnel
4.6 Two conditions must be met to optimize SGS assay
C1592/C1592MGuide for Making Quality Nondestructive
results as follows:
Assay Measurements (Withdrawn 2018)
C1673Terminology of C26.10 NondestructiveAssay Meth-
ods
E181Test Methods for Detector Calibration andAnalysis of
Radionuclides
2.2 ANSI Standards:
ANSI/IEEE 325Test Procedures for Germanium Gamma-
Ray Detectors
ANSI N15.36 Measurement Control Program—
Nondestructive Assay Measurement Control and Assur-
ance
3. Terminology
3.1 Refer to Terminology C1673 for terminology defini-
tions.
4. Summary of Test Method
4.1 The assay of the nuclides of interest is accomplished by
measuring the intensity of one or more characteristic gamma
rays from each nuclide. Corrections are made for count
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
The last approved version of this historical standard is referenced on
www.astm.org.
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St., FIG. 1 Typical Arrangement for Segmented Gamma-Ray Scan-
4th Floor, New York, NY 10036, http://www.ansi.org. ning
C1133/C1133M − 10 (2018)
4.6.1 The particles containing the nuclides of interest must measurementmethodused.Also,processknowledgeshouldbe
besmallenoughtominimizeself-absorptionofemittedgamma used, when available, as part of a waste management program
radiation (13).
to complement information on item parameters, container
4.6.1.1 Under specific conditions, particles large enough to properties, and the appropriateness of calibration factors.
provide significant self absorption (lumps) may be assayed
5.4 To obtain the lowest detection levels, a two-pass assay
accurately. These conditions include use of specific nuclide
should be used. The two-pass assay also reduces problems
differential peak calibration and calibration using mass stan-
related to potential interferences between transmission peaks
dards that have the same attenuation characteristics over the
and assay peaks. For items with higher activities, a single-pass
energy range used for quantitative measurements as the mate-
assay may be used to increase throughput.
rials to be assayed.
4.6.1.2 An alternative approach to mass calibration with
6. Interferences
standards that contain the same sized particles is to apply
correctionalgorithmsthatarebasedonthedifferentialresponse
6.1 Radionuclides may be present in the assay item that
of two or more peaks at different energies from the same
produce gamma rays with energies that are the same or very
nuclide. For example, the 129 and 414 keV peaks of Pu or
nearly the same as the gamma rays suggested for nuclide or
the 144 and 186 keV peaks of U could be used (see 7.7).
transmission measurement. The areas of the closely spaced
4.6.1.3 The presence of lumps in material being assayed
peaks that are produced in the gamma-ray spectrum cannot be
also can be detected using differential peak response algo-
calculated by simple spectroscopic procedures. Peak fitting
rithms.
software routines may be able to resolve closely spaced peaks
4.6.2 The mixture of material within each item segment
in some cases; alternatively, the nuclide of interest may
must be sufficiently uniform to apply an attenuation correction
produce other gamma rays that may be used for analysis.
factor, generally computed from a measurement of gamma-ray
6.1.1 Thepeakproducedbythe661.6-keVgammarayfrom
transmission through the segment.
Cs would interfere with calculation of the area of the
4.7 Thecorrectedgamma-raycountratesforthenuclidesof
Am peak produced by its 662.4-keV gamma ray. The
interest are determined on a segment-by-segment basis. The
721.9-keV gamma ray of Am may be a useful alternative.
precision of the measured count rate of each gamma ray used
6.1.2 Thepeakproducedbythe765.8-keVgammarayfrom
for analysis is also estimated on a segment-by-segment basis.
95 238
Nb would interfere with calculation of the area of the Pu
At the completion of the measurement of all segments,
peak produced by its 766.4-keV gamma ray. The 786.3-keV
corrected count rates are summed, and mass values for the
gamma ray of Pu may be a useful alternative.
nuclides of interest in the entire container are calculated based
6.1.3 Occasionally, Np is found in the presence of pluto-
either on comparisons to appropriate calibration materials or
237 233
nium. The Np daughter, Pa, emits a gamma ray at 415.8-
from the gamma emission rates determined from the segment
keV along with several gamma rays in the range from 300 to
efficienciesdeterminedovertheenergyrangeofinterest.Based
400 keV. Peaks from these gamma rays would interfere with
on counting statistics for individual segments, precision values
calculation of the area of the Pu peak produced by its
arepropagatedtoobtaintheestimatedprecisionoftheanalysis.
413.7-keV gamma ray and several other often used peaks
4.8 In the event that a single nuclide of an element is
from Pu. In this case, the peak produced by the 129.3-keV
measured and the total element mass is required (for ex-
gamma ray of Pu may be the only reasonable alternative.
ample, Pu and total plutonium), it is common practice to
6.1.4 The peak produced by the 63.1-keV gamma ray
apply a known or estimated nuclide/total element ratio to the
from Yb, sometimes used as the transmission source
nuclide assay value to determine the total element content.
for U assays, may interfere with calculation of the area of
4.8.1 Isotope ratios can be determined using gamma isoto-
the peak produced by the 59.5-keV gamma ray of Am,
pic analysis techniques such as those described inTest Method
which is used as the count rate correction source. The Yb
C1030.
gammaraycanbesufficientlyattenuatedbyplacingacadmium
absorber over the transmission source or the problem can be
5. Significance and Use
avoided altogether by using a two-pass assay. In a two-pass
5.1 Segmented gamma-ray scanning provides a nondestruc-
assay, the first measurement pass measures the intensity of the
tivemeansofmeasuringthenuclidecontentofscrapandwaste
transmission source for each segment. The second measure-
where the specific nature of the matrix and the chemical form 239
ment pass measures the intensity of the 413.7-keV Pu
and relationship between the nuclide and matrix may be
gamma-ray emission from each segment with the transmission
unknown.
source shutter closed.
5.2 The procedure can serve as a diagnostic tool that
6.1.5 Transmission source peaks may have errors intro-
provides a vertical profile of transmission and nuclide concen-
duced by the presence of a radionuclide in the assay material
tration within the item.
that emits gamma rays at or near one or more of the measured
transmission energies. The affected measurements will then be
5.3 Item preparation is generally limited to good waste/
scrap segregation practices that produce relatively homoge- higher than the actual transmissions through the item, leading
neous items that are required for any successful waste/ to calculation of a lower than actual correction factor and
inventory management and assay scheme, regardless of the quantity of measured radionuclide.
C1133/C1133M − 10 (2018)
239 75
6.2 In the case of Pu assays using Se as a transmission fixed absorbers, typically cadmium, tin,
...
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