ASTM C1133 C1133M-2010(2018) Standard Test Method for Nondestructive Assay of Special Nuclear Material in Low-Density Scrap and Waste by Segmented Passive Gamma-Ray Scanning《用分段无源伽.pdf

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1、Designation: C1133/C1133M 10 (Reapproved 2018)Standard Test Method forNondestructive Assay of Special Nuclear Material in Low-Density Scrap and Waste by Segmented Passive Gamma-Ray Scanning1This standard is issued under the fixed designation C1133/C1133M; the number immediately following the designa

2、tion indicates the yearof 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 () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the trans

3、mission-corrected non-destructive assay (NDA) of gamma-ray emitting specialnuclear materials (SNMs), most commonly235U,239Pu,and241Am, in low-density scrap or waste, packaged in cylin-drical containers. The method can also be applied to NDA ofother gamma-emitting nuclides including fission products.

4、High-resolution gamma-ray spectroscopy is used to detect andmeasure the nuclides of interest and to measure and correct forgamma-ray attenuation in a series of horizontal segments(collimated gamma detector views) of the container. Correc-tions are also made for counting losses occasioned by signalpr

5、ocessing limitations (1-3).21.2 There are currently several systems in use or underdevelopment for determining the attenuation corrections forNDA of radioisotopic materials (4-8). A related technique,tomographic gamma-ray scanning (TGS), is not included inthis test method (9, 10, 11).1.2.1 This test

6、 method will cover two implementations ofthe Segmented Gamma Scanning (SGS) procedure: (1) IsotopeSpecific (Mass) Calibration, the original SGS procedure, usesstandards of known radionuclide masses to determine detectorresponse in a mass versus corrected count rate calibration thatapplies only to th

7、ose specific radionuclides for which it iscalibrated, and (2) Efficiency Curve Calibration, an alternativemethod, typically uses non-SNM radionuclide sources todetermine system detection efficiency vs. gamma energy andthereby calibrate for all gamma-emitting radionuclides ofinterest (12).1.2.1.1 Eff

8、iciency Curve Calibration, over the energy rangefor which the efficiency is defined, has the advantage ofproviding calibration for many gamma-emitting nuclides forwhich half-life and gamma emission intensity data are avail-able.1.3 The assay technique may be applicable to loadings up toseveral hundr

9、ed grams of nuclide in a 208-L 55-gal drum,with more restricted ranges to be applicable depending onspecific packaging and counting equipment considerations.1.4 Measured transmission values must be available for usein calculation of segment-specific attenuation corrections at theenergies of analysis

10、.1.5 A related method, SGS with calculated correction fac-tors based on item content and density, is not included in thisstandard.1.6 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; there

11、fore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.7 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standar

12、d to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.Specific precautionary statements are given in Section 10.1.8 This international standard was developed in accor-dance with internationally recognized princ

13、iples on standard-ization established in the Decision on Principles for the1This test method is under the jurisdiction ofASTM Committee C26 on NuclearFuel Cycle and is the direct responsibility of Subcommittee C26.10 on NonDestructive Assay.Current edition approved April 1, 2018. Published April 201

14、8. Originallyapproved in 1996. Last previous edition approved in 2010 as C1133/C1133M 10.DOI: 10.1520/C1133_C1133M-10R18.2The boldface numbers in parentheses refer to the list of references at the end ofthis test method.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohoc

15、ken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organiz

16、ation Technical Barriers to Trade (TBT) Committee.1Development of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:3C1030 Test Method for Determination of Plutonium Isotopi

17、cComposition by Gamma-Ray SpectrometryC1128 Guide for Preparation of Working Reference Materi-als for Use in Analysis of Nuclear Fuel Cycle MaterialsC1156 Guide for Establishing Calibration for a Measure-ment Method Used to Analyze Nuclear Fuel Cycle Mate-rialsC1207 Test Method for Nondestructive As

18、say of Plutoniumin Scrap and Waste by Passive Neutron CoincidenceCountingC1210 Guide for Establishing a Measurement System Qual-ity Control Program for Analytical Chemistry Laborato-ries Within the Nuclear IndustryC1215 Guide for Preparing and Interpreting Precision andBias Statements in Test Method

19、 Standards Used in theNuclear IndustryC1316 Test Method for Nondestructive Assay of NuclearMaterial in Scrap and Waste by Passive-Active NeutronCounting Using252Cf ShufflerC1458 Test Method for Nondestructive Assay of Plutonium,Tritium and241Am by Calorimetric AssayC1490 Guide for the Selection, Tra

20、ining and Qualification ofNondestructive Assay (NDA) PersonnelC1592/C1592M Guide for Making Quality NondestructiveAssay Measurements (Withdrawn 2018)4C1673 Terminology of C26.10 Nondestructive Assay Meth-odsE181 Test Methods for Detector Calibration and Analysis ofRadionuclides2.2 ANSI Standards:5AN

21、SI/IEEE 325 Test Procedures for Germanium Gamma-Ray DetectorsANSI N15.36 Measurement Control ProgramNondestructive Assay Measurement Control and Assur-ance3. Terminology3.1 Refer to Terminology C1673 for terminology defini-tions.4. Summary of Test Method4.1 The assay of the nuclides of interest is a

22、ccomplished bymeasuring the intensity of one or more characteristic gammarays from each nuclide. Corrections are made for countrate-related losses and attenuation by the item. The appropriatemass or efficiency calibration then provides the relationshipbetween observed gamma-ray intensity and nuclide

23、 content.4.2 Either of two distinct calibration methods can be used:4.2.1 Isotope Specific Calibration provides assay results foronly those radionuclides for which the SGS is specificallycalibrated. Calibration is performed using standards containingthe radionuclides to be assayed.4.2.2 Effciency Cu

24、rve Calibration entails determination ofthe system detection efficiency as a function of gamma rayenergy. Analysis of assay data consists of using the energy ofa peak to infer the emitting radionuclide, and then calculatingthe radionuclide mass from the specific activity and the gammaemission intens

25、ity of the radionuclide, and the corrected countrate and detector efficiency at the peak energy.4.3 The assay item is rotated about its vertical axis andscanned segment by segment along that axis, thereby reducingthe effects of nonuniformity in both matrix density and nuclidedistribution (see Fig. 1

26、).4.4 Count rate-dependent losses from pulse pile-up andanalyzer dead time are corrected for by electronic modules, aradioactive source, a pulser, or a combination of these.4.5 The average linear attenuation coefficient of each hori-zontal segment is calculated by measurement of the transmittedinten

27、sity of an appropriate external gamma-ray source. Thesource is mounted directly opposite the gamma-ray detector, onthe far side of the assay item (see Fig. 1).4.6 Two conditions must be met to optimize SGS assayresults as follows:3For referenced ASTM standards, visit the ASTM website, www.astm.org,

28、orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4The last approved version of this historical standard is referenced onwww.astm.org.5Available from American National Standards Ins

29、titute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.FIG. 1 Typical Arrangement for Segmented Gamma-Ray Scan-ningC1133/C1133M 10 (2018)24.6.1 The particles containing the nuclides of interest mustbe small enough to minimize self-absorption of emitted gammaradiation (13).4.

30、6.1.1 Under specific conditions, particles large enough toprovide significant self absorption (lumps) may be assayedaccurately. These conditions include use of specific nuclidedifferential peak calibration and calibration using mass stan-dards that have the same attenuation characteristics over thee

31、nergy range used for quantitative measurements as the mate-rials to be assayed.4.6.1.2 An alternative approach to mass calibration withstandards that contain the same sized particles is to applycorrection algorithms that are based on the differential responseof two or more peaks at different energie

32、s from the samenuclide. For example, the 129 and 414 keV peaks of239Pu orthe 144 and 186 keV peaks of235U could be used (see 7.7).4.6.1.3 The presence of lumps in material being assayedalso can be detected using differential peak response algo-rithms.4.6.2 The mixture of material within each item se

33、gmentmust be sufficiently uniform to apply an attenuation correctionfactor, generally computed from a measurement of gamma-raytransmission through the segment.4.7 The corrected gamma-ray count rates for the nuclides ofinterest are determined on a segment-by-segment basis. Theprecision of the measure

34、d count rate of each gamma ray usedfor analysis is also estimated on a segment-by-segment basis.At the completion of the measurement of all segments,corrected count rates are summed, and mass values for thenuclides of interest in the entire container are calculated basedeither on comparisons to appr

35、opriate calibration materials orfrom the gamma emission rates determined from the segmentefficiencies determined over the energy range of interest. Basedon counting statistics for individual segments, precision valuesare propagated to obtain the estimated precision of the analysis.4.8 In the event t

36、hat a single nuclide of an element ismeasured and the total element mass is required (for ex-ample,239Pu and total plutonium), it is common practice toapply a known or estimated nuclide/total element ratio to thenuclide assay value to determine the total element content.4.8.1 Isotope ratios can be d

37、etermined using gamma isoto-pic analysis techniques such as those described in Test MethodC1030.5. Significance and Use5.1 Segmented gamma-ray scanning provides a nondestruc-tive means of measuring the nuclide content of scrap and wastewhere the specific nature of the matrix and the chemical formand

38、 relationship between the nuclide and matrix may beunknown.5.2 The procedure can serve as a diagnostic tool thatprovides a vertical profile of transmission and nuclide concen-tration within the item.5.3 Item preparation is generally limited to good waste/scrap segregation practices that produce rela

39、tively homoge-neous items that are required for any successful waste/inventory management and assay scheme, regardless of themeasurement method used.Also, process knowledge should beused, when available, as part of a waste management programto complement information on item parameters, containerprop

40、erties, and the appropriateness of calibration factors.5.4 To obtain the lowest detection levels, a two-pass assayshould be used. The two-pass assay also reduces problemsrelated to potential interferences between transmission peaksand assay peaks. For items with higher activities, a single-passassay

41、 may be used to increase throughput.6. Interferences6.1 Radionuclides may be present in the assay item thatproduce gamma rays with energies that are the same or verynearly the same as the gamma rays suggested for nuclide ortransmission measurement. The areas of the closely spacedpeaks that are produ

42、ced in the gamma-ray spectrum cannot becalculated by simple spectroscopic procedures. Peak fittingsoftware routines may be able to resolve closely spaced peaksin some cases; alternatively, the nuclide of interest mayproduce other gamma rays that may be used for analysis.6.1.1 The peak produced by th

43、e 661.6-keV gamma ray from137Cs would interfere with calculation of the area of the241Am peak produced by its 662.4-keV gamma ray. The721.9-keV gamma ray of241Am may be a useful alternative.6.1.2 The peak produced by the 765.8-keV gamma ray from95Nb would interfere with calculation of the area of th

44、e238Pupeak produced by its 766.4-keV gamma ray. The 786.3-keVgamma ray of238Pu may be a useful alternative.6.1.3 Occasionally,237Np is found in the presence of pluto-nium. The237Np daughter,233Pa, emits a gamma ray at 415.8-keV along with several gamma rays in the range from 300 to400 keV. Peaks fro

45、m these gamma rays would interfere withcalculation of the area of the239Pu peak produced by its413.7-keV gamma ray and several other often used peaksfrom239Pu. In this case, the peak produced by the 129.3-keVgamma ray of239Pu may be the only reasonable alternative.6.1.4 The peak produced by the 63.1

46、-keV gamma rayfrom169Yb, sometimes used as the transmission sourcefor235U assays, may interfere with calculation of the area ofthe peak produced by the 59.5-keV gamma ray of241Am,which is used as the count rate correction source. The169Ybgamma ray can be sufficiently attenuated by placing a cadmiuma

47、bsorber over the transmission source or the problem can beavoided altogether by using a two-pass assay. In a two-passassay, the first measurement pass measures the intensity of thetransmission source for each segment. The second measure-ment pass measures the intensity of the 413.7-keV239Pugamma-ray

48、 emission from each segment with the transmissionsource shutter closed.6.1.5 Transmission source peaks may have errors intro-duced by the presence of a radionuclide in the assay materialthat emits gamma rays at or near one or more of the measuredtransmission energies. The affected measurements will

49、then behigher than the actual transmissions through the item, leadingto calculation of a lower than actual correction factor andquantity of measured radionuclide.C1133/C1133M 10 (2018)36.2 In the case of239Pu assays using75Se as a transmissionsource, random coincident summing of the 136.00 and 279.53-keV gamma-ray emissions from75Se produces a low-intensitypeak at 415.5-keV that interferes with calculation of the area ofthe239Pu peak produced by its 413.7-keV gamma ray. Theeffects of this sum-peak can be reduced by attenuating theradiation from the transmission source to the