ASTM_C_1500_-_08_2017.pdf

Designation:C150008(Reapproved 2017)Standard Test Method forNondestructive Assay of Plutonium by Passive NeutronMultiplicity Counting1This standard is issued under the fixed designation C1500;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method describes the nondestructive assay ofplutonium in forms such as metal,oxide,scrap,residue,orwaste using passive neutron multiplicity counting.This testmethod provides results that are usually more accurate thanconventional neutron coincidence counting.The method can beapplied to a large variety of plutonium items in variouscontainers including cans,208-L drums,or 1900-L StandardWaste Boxes.It has been used to assay items whose plutoniumcontent ranges from 1 g to 1000s of g.1.2 There are several electronics or mathematical ap-proaches available for multiplicity analysis,including themultiplicity shift register,the Euratom Time CorrelationAnalyzer,and the List Mode Module,as described briefly inRef.(1).21.3 This test method is primarily intended to address theassay of240Pu-effective by moments-based multiplicity analy-sis using shift register electronics(1,2,3)and high efficiencyneutron counters specifically designed for multiplicity analysis.1.4 This test method requires knowledge of the relativeabundances of the plutonium isotopes to determine the totalplutonium mass(See Test Method C1030).1.5 This test method may also be applied to modifiedneutron coincidence counters(4)which were not specificallydesigned as multiplicity counters(that is,HLNCC,AWCC,etc),with a corresponding degradation of results.1.6 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.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 standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:3C1030 Test Method for Determination of Plutonium IsotopicComposition by Gamma-Ray SpectrometryC1207 Test Method for Nondestructive Assay of Plutoniumin Scrap and Waste by Passive Neutron CoincidenceCountingC1458 Test Method for Nondestructive Assay of Plutonium,Tritium and241Am by Calorimetric AssayC1490 Guide for the Selection,Training and Qualification ofNondestructive Assay(NDA)PersonnelC1592 Guide for Nondestructive Assay MeasurementsC1673 Terminology of C26.10 Nondestructive Assay Meth-ods3.Terminology3.1 Definitions:3.1.1 Terms shall be defined in accordance with Terminol-ogy C1673 except for the following:3.1.2 gate fractions,nthe fraction of the total coincidenceevents that occur within the coincidence gate.3.1.2.1 doubles gate fraction(fd),nthe fraction of thetheoretical double coincidences that can be detected within thecoincidence gate(see Eq 1).3.1.2.2 triples gate fraction(ft),nthe fraction of thetheoretical triple coincidences that can be detected within thecoincidence gate(see Eq 2).3.1.3 factorial moment of order,nthis is a derived quantitycalculated by summing the neutron multiplicity distributionweighted by!/(n)!where n is the order of the moment.3.1.4 induced fission neutron multiplicities(i1,i2,i3),nthe factorial moments of the induced fission neutron mul-tiplicity distribution.Typically multiplicity analysis will utilize1This 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 Jan.1,2017.Published January 2017.Originallyapproved in 2002.Last previous edition approved in 2008 as C1500 08.DOI:10.1520/C1500-08R17.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.3For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,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 Organization Technical Barriers to Trade(TBT)Committee.1 the data from fast neutron-induced fission of239Pu to calculatethese moments(5,6).4.Summary of Test Method4.1 The item is placed in the sample chamber or“well”ofthe multiplicity counter,and the emitted neutrons are detectedby the3He tubes that surround the well.4.2 The detecte