ASTM_C_1235_-_99.pdf

Designation:C 1235 99Standard Test Method forPlutonium by Titanium(III)/Cerium(IV)Titration1This standard is issued under the fixed designation C 1235;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(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method is applicable to the assay or puritydetermination of plutonium metal of 98%purity or higher.Uranium and iron are known interferences and must bedetermined separately.Their respective corrections must thenbe made to the assay value.1.2 The recommended amount of plutonium determined inthe titration is 210 to 240 mg.1.3 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:C 1009 Guide for Establishing a Quality Assurance Pro-gram for Analytical Chemistry Laboratories Within theNuclear Industry2C 1068 Guide for Qualification of Measurement Methodsby a Laboratory Within the Nuclear Industry2C 1128 Guide for Preparation of Working Reference Mate-rials for Use in the Analysis of Nuclear fuel CycleMaterials2C 1156 Guide for Establishing Calibration for a Measure-ment Method Used to Analyze Nuclear Fuel Cycle Mate-rials2C 1210 Guide for Establishing a Measurement SystemQuality Control Program for Analytical Chemistry Labo-ratories Within the Nuclear Industry2C 1297 Guide for Qualification of Laboratory Analysts forthe Analysis of Nuclear Fuel Cycle Materials23.Summary of Test Method3.1 In a redox titration,as titrant is added,the change inconcentration of the redox couple is monitored.This change inconcentration of the redox couple can be monitored bymeasuring the potential difference between a platinum indica-tor electrode and a reference electrode(such as a saturatedcalomel electrode)in contact with the solution or by otherequivalent methods of endpoint determination.The endpoint ofthe titration is usually chosen to be the point at which the rateof change in concentration of the redox couple is greatest perincrement of titrant added.The concentration of analyte iscalculated from the volume or mass of titrant added to reachthe endpoint,the concentration of the titrant,and the mass ofthe sample titrated.Lingane(1)3discusses the principles ofautomatic potentiometric titrations,and Meites(2)lists numer-ous examples of potentiometric redox titrations.3.2 This test method is an adaptation of the Corpel andRegnaud method(3)in which the plutonium in solution isreduced to Pu(III)with titanium(III)chloride,excess Ti(III)isdestroyed with nitric acid,and finally,the reduced plutonium isoxidized to Pu(IV)with ceric titrant using ferroin indicator.However,this adaptation substitutes a potentiometric endpointfor the indicator endpoint and uses commercial titration instru-mentation(4,5).3.3 This test method was developed for production supportand has distinct advantages when a large number of samplesare to be analyzed.It is largely automated,accomplishing atitration approximately every 2 min when optimizing step-wiseoperations.Variations on this test method,such as manualtitration with visual or photometric endpoint detection or use ofa weight buret would,no doubt,provide quality data,but at theexpense of limiting sample throughput.4.Significance and Use4.1 This test method is designed to determine the plutoniumcontent of plutonium metal.4.2 Committee C-26 Safeguards Statement4:4.2.1 The material(plutonium metal)to which this testmethod applies is subject to nuclear safeguards regulationsgoverning its possession and use.Materials for use by thecommercial nuclear community must also meet compositionalspecifications.4.2.2 The analytical method in this test method both meetsU.S.Department of Energy guidelines for acceptability of ameasurement method for generation of safeguards accountabil-ity measurement data and also provides data that may be used1This test method is under the jurisdiction ofASTM Committee C-26 on NuclearFuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods ofTest.Current edition approved Jan.10,1999.Published February 1999.Originallypublished as C 1235 93.Last previous edition C 1235 93a.2Annual Book of ASTM Standards,Vol 12.01.3The boldface numbers in parentheses refer to the list of references at the end ofthis test method.4Based upon Committee C-26 Safeguards Matrix(C 1009,C 1068,C 1128,C 1156,C 1210,and C 1297).1AMERICAN SOCIETY FOR TESTING AND MATERIALS100 Barr Harbor Dr.,West Conshohocken,PA 19428Reprinted from the Annual Book of ASTM Standards.Copyright ASTMto demonstrate specification compliance in buyer-seller inter-actions.5.Interferences5.1 Interference