ASTM_C_1308_-_08_2017.pdf

Designation:C130808(Reapproved 2017)Standard Test Method forAccelerated Leach Test for Diffusive Releases fromSolidified Waste and a Computer Program to ModelDiffusive,Fractional Leaching from Cylindrical WasteForms1This standard is issued under the fixed designation C1308;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 provides procedures for measuring theleach rates of elements from a solidified matrix material,determining if the releases are controlled by mass diffusion,computing values of diffusion constants based on models,andverifying projected long-term diffusive releases.This testmethod is applicable to any material that does not degrade ordeform during the test.1.1.1 If mass diffusion is the dominant step in the leachingmechanism,then the results of this test can be used to calculatediffusion coefficients using mathematical diffusion models.Acomputer program developed for that purpose is available as acompanion to this test method(Note 1).1.1.2 It should be verified that leaching is controlled bydiffusion by a means other than analysis of the leach testsolution data.Analysis of concentration profiles of species ofinterest near the surface of the solid waste form after the test isrecommended for this purpose.1.1.3 Potential effects of partitioning on the test results canbe identified through modeling,although further testing andanalyses are required to determine the cause of partitioning(forexample,if it occurs during production of the material or as aresult of leaching).1.2 The method is a modification of other semi-dynamictests such as the IAEA test(1)2and the ANS 16.1 Leach Testwherein elevated temperatures are used to accelerate diffusiverelease to an extent that would only be reached after very longtimes at lower temperatures.This approach provides a mecha-nistic basis for calculating diffusive releases at repository-relevant temperatures over long times,provided that theleaching mechanism does not change with temperature.1.2.1 Tests can be conducted at elevated temperatures toaccelerate diffusive release and provide a mechanistic basis forcalculating diffusive releases that would occur at lower tem-peratures over long times.Tests conducted at high temperaturesallow the temperature dependence of the diffusion coefficientto be determined.They also demonstrate that the diffusionmechanism is rate-limiting through the measured extent ofdiffusive release.1.2.2 Releases at any temperature can be projected up to thehighest cumulative fractional release value that has beenmeasured for that material(at any temperature),provided thatthe mechanism does not change.The mechanism is consideredto remain unchanged over a range of temperatures if thediffusion coefficients show Arrhenius behavior over that range.NOTE1A computer program in which the test results are evaluatedusing three diffusion models is briefly described in Annex A1 and in theAccelerated Leach Test Method and Users Guide for the“ALT”Com-puter Program(2).The data are fit with model equations for diffusion froma semi-infinite solid,diffusion from a finite cylinder,and diffusion withpartitioning of the species of interest to determine effective diffusioncoefficients and quantify the goodness of fit.The Users Guide containsseveral typographical errors;these are identified in Annex A1.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.4 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:3C1220 Test Method for Static Leaching of Monolithic WasteForms for Disposal of Radioactive Waste1This test method is under the jurisdiction ofASTM Committee C26 on NuclearFuel Cycle and is the direct responsibility of Subcommittee C26.13 on Spent Fueland High Level Waste.Current edition approved Jan.1,2017.Published January 2017.Originallyapproved in 1995.Last previous edition approved in 2008 as C1308 08.DOI:10.1520/C1308-08R17.2The 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 sta