ASTM_C_1807_-_15.pdf

Designation:C180715Standard Guide forNondestructive Assay of Special Nuclear Material(SNM)Holdup Using Passive Neutron Measurement Methods1This standard is issued under the fixed designation C1807;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 guide describes passive neutron measurementmethods used to nondestructively estimate the amount ofneutron-emitting special nuclear material compounds remain-ing as holdup in nuclear facilities.Holdup occurs in allfacilities in which nuclear material is processed.Material mayexist,for example,in process equipment,in exhaust ventilationsystems,and in building walls and floors.1.1.1 The most frequent uses of passive neutron holduptechniques are for the measurement of uranium or plutoniumdeposits in processing facilities.1.2 This guide includes information useful for management,planning,selectionofequipment,considerationofinterferences,measurement program definition,and the utili-zation of resources.1.3 Counting modes include both singles(totals)or grosscounting and neutron coincidence techniques.1.3.1 Neutron holdup measurements of uranium are typi-cally performed on neutrons emitted during(,n)reactions andspontaneous fission using singles(totals)or gross counting.While the method does not preclude measurement usingcoincidence or multiplicity counting for uranium,measurementefficiency is generally not sufficient to permit assays inreasonable counting times.1.3.2 For measurement of plutonium in gloveboxes,in-stalled measurement equipment may provide sufficient effi-ciency for performing counting using neutron coincidencetechniques in reasonable counting times.1.4 The measurement of nuclear material holdup in processequipment requires a scientific knowledge of radiation sourcesand detectors,radiation transport,modeling methods,calibration,facility operations,and uncertainty analysis.It issubject to the constraints of the facility,management,budget,and schedule,plus health and safety requirements,as well asthe laws of physics.This guide does not purport to instruct theNDA practitioner on these principles.1.5 The measurement process includes defining measure-mentuncertaintiesandissensitivetothechemicalcomposition,isotopic composition,distribution of the material,various backgrounds,and interferences.The work includesinvestigation of material distributions within a facility,whichcould include potentially large holdup surface areas.Nuclearmaterial held up in pipes,ductwork,gloveboxes,and heavyequipment is usually distributed in a diffuse and irregularmanner.It is difficult to define the measurement geometry,identify the form of the material,and measure it.1.6 UnitsThe values stated in SI units are to be regardedas the standard.No other units of measurement are included inthis 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 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:2C1009 Guide for Establishing and Maintaining a QualityAssurance Program forAnalytical Laboratories Within theNuclear IndustryC1455 Test Method for Nondestructive Assay of SpecialNuclear Material Holdup Using Gamma-Ray Spectro-scopic MethodsC1490 Guide for the Selection,Training and Qualification ofNondestructive Assay(NDA)PersonnelC1592/C1592M Guide for Making Quality NondestructiveAssay MeasurementsC1673 Terminology of C26.10 Nondestructive Assay Meth-ods2.2 NRC Standard:NRC Regulatory Guide 5.23 In-Situ Assay of PlutoniumResidual Holdup31This guide is under the jurisdiction of ASTM Committee C26 on Nuclear FuelCycle and is the direct responsibility of Subcommittee C26.10 on Non DestructiveAssay.Current edition approved Jan.1,2015.Published January 2015.DOI:10.1520/C1807-15.2For 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.3Available from U.S.Nuclear Regulatory Commission(NRC),One White FlintNorth,11555 Rockville Pk.,Rockville,MD 20852-2738,http:/www.nrc.gov.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 2.3 ANSI Standard:ANSI N15.20 Guide to Calibrating Nondestructive AssaySystems43.Terminology3.1 DefinitionsRefer to Terminology C1673 for defini-tions used in this guide.4.Summary of Guide4.1 IntroductionHoldup measurements using neutronmethods typically measure the(,n)or spontaneous fissionproduction of neutrons,or both.Neutrons generated in itemsthat do not include significant