1、Designation:C145816Standard Test Method forNondestructive Assay of Plutonium,Tritium and241Am byCalorimetric Assay1This standard is issued under the fixed designation C1458;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of
2、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(NDA)of plutonium,tritium,and241Am using heat flowcalorimetry.For pluton
3、ium the typical range of applicability,depending on the isotopic composition,corresponds to 0.1 gto 5 g quantities while for tritium the typical range extendsfrom 0.001 g to 400 g.This test method can be applied tomaterials in a wide range of container sizes up to 380 L.It hasbeen used routinely to
4、assay items whose thermal power rangesfrom 0.001 W to 135 W.1.2 This test method requires knowledge of the relativeabundances of the plutonium isotopes and the241Am/Pu massratio to determine the total plutonium mass.1.3 This test method provides a direct measure of tritiumcontent.1.4 This test metho
5、d provides a measure of241Am either asa single isotope or mixed with plutonium.1.5 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.6 This standard does not purport to address all of thesafety concerns,if any,associated with its
6、 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:2C697 Test Methods for Chemical,Mass Spectrometric,andSpectrochemical Analy
7、sis of Nuclear-Grade PlutoniumDioxide Powders and PelletsC1009 Guide for Establishing and Maintaining a QualityAssurance Program forAnalytical Laboratories Within theNuclear IndustryC1030 Test Method for Determination of Plutonium IsotopicComposition by Gamma-Ray SpectrometryC1592 Guide for Nondestr
8、uctive Assay MeasurementsC1673 Terminology of C26.10 Nondestructive Assay Meth-ods2.2 ANSI Standard:3ANSI N15.36 Measurement Control Program Nondestruc-tive Assay Measurement Control and Assurance3.Terminology3.1 Definitions:3.1.1 Terms shall be defined in accordance with C26.10Terminology C1673 exc
9、ept for the following:3.1.2 active modea mode of calorimeter operation wherean external power,applied by means of a series of band heatersfor instance,is used to maintain the calorimeter at constanttemperature.3.1.3 baseline,nthe calorimeter output signal with noheat-generating item in the calorimet
10、er item chamber.3.1.4 base power,na constant thermal power applied in acalorimeter through an electrical resistance heater with noheat-generating item in the item chamber.3.1.5 equilibrium,nthe point at which the temperature ofthe calorimeter measurement cell and the item being measuredstabilizes.3.
11、1.6 heat distribution error,nthe bias arising from thelocation of the heat source within the calorimeter chamber.3.1.7 passive mode,na mode of calorimeter operationwhere temperature change(caused by the heat to be quantified)is measured by means of temperature sensors with no externalpower applied e
12、xcept in the case of Wheatstone bridge tem-perature sensors where electrical current is needed to excite thebridge circuit.1This 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 edi
13、tion approved March 1,2016.Published April 2016.Originallyapproved in 2000.Last previous edition approved in 2009 as C1458 091.DOI:10.1520/C1458-16.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards v
14、olume information,refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.Un
15、ited States1 3.1.8 power compensation mode,na mode of calorimeteroperation where a constant applied thermal power is main-tained in a calorimeter measurement chamber through the useof an electric resistance heater in a closed loop control system.Historically,Mound Laboratory used to call this“Servo
16、Con-trol.”3.1.9 sensitivity,nthe change in calorimeter response perWatt of thermal power(usually in units of V/W)for a heatflow calorimeter.3.1.10 specific power,nthe rate of energy emission byionizing radiation per unit mass of a radionuclide,suchas241Am or tritium.3.1.11 thermal diffusivity,nthe ratio of thermal conductiv-ity to the heat capacity.It measures the ability of a material toconduct thermal energy relative to its ability to store thermalenergy.3.1.12 thermal power,nthe rate at which