ASTM_C_1346_-_08_2014.pdf

Designation:C134608(Reapproved 2014)Standard Practice forDissolution of UF6from P-10 Tubes1,2This standard is issued under the fixed designation C1346;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 practice covers the dissolution of UF6from a P-10tube to provide solutions for analysis.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.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.For specificsafeguard and safety precaution statements,see Section 8.2.Referenced Documents2.1 ASTM Standards:3C761 Test Methods for Chemical,Mass Spectrometric,Spectrochemical,Nuclear,and Radiochemical Analysis ofUranium HexafluorideC787 Specification for Uranium Hexafluoride for Enrich-mentC996 Specification for Uranium Hexafluoride Enriched toLess Than 5%235UD1193 Specification for Reagent Water3.Summary of Practice3.1 UF6samples intended for analysis are packaged in P-10tubes to prevent sublimation and reaction with moisture in theair.The P-10 tube assembly(Fig.1)consists of a Polychloro-trifluoroethylene(PCTFE)tube containing the UF6,a PCTFEgasket to cover the tubes opening,and a nut and plug(Monelor SS)to seal the gasket to the tube.3.2 The UF6tube is weighed,cooled in liquid nitrogen,andquickly opened and immersed in water for dissolution.Thepieces of the tubes assembly are removed from the resultingsolution,rinsed,dried,reassembled,and weighed.The solutionis dried for gravimetric conversion to U3O8,or diluted to anappropriate concentration for dispensing into aliquots forsubsequent analysis.4.Significance and Use4.1 Uranium hexafluoride is a basic material used to preparenuclear reactor fuel.To be suitable for this purpose the materialmust meet criteria for uranium content,isotopic compositionand metallic impurities in Specification C787 and C996.Thispractice results in the complete dissolution of the sample foruranium and impurities analysis,and determination of isotopicdistribution by mass spectrometry as described in,for example,Test Methods C761.5.Apparatus5.1 Steam bath,in a hood,if optional step 9.2.13 is used.5.2 Vacuum oven,if option 2 of 9.2.14 is used.The ovenshould be adjustable to 80C at an absolute pressure of 3 103Pa.5.3 Dewar flask,wide-mouth.5.4 Vise,small lab-bench model or similar type of holder.5.5 Wrench,1516in.5.6 Plastic clamping forceps,12 to 13 cm long,with aclaw-like bent tip,to securely hold the cylindrical PCTFE tube.NOTE1These forceps are not commercially available.Bend the endsof a straight-tip forceps by heating over a moderate flame,shaping,andmaintaining the shape until cool.5.7 TFE-fluorocarbon-coated spatula,0.5-to 1-cm wide atits flat end,optional.5.8 Platinum or PCTFE rod,optional.5.9 Platinum dishes or plastic beakers with compatible HFresistance(typically PolyEthylene;PE),large enough to con-tain a completely submerged P-10 tube.1This practice is under the jurisdiction of ASTM Committee C26 on NuclearFuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods ofTest.Current edition approved Jan.1,2014.Published February 2014.Originallyapproved in 1996.Last previous edition approved in 2008 as C1346 08.DOI:10.1520/C1346-08R14.2Polychlorotrifluoroethylene P-10 tubes are widely accepted by the industry forsubsample collection and subsequent UF6quality analyses or dispatch to thecustomer.The procedure for subsample collection and dissolution can also be usedfor other types of subsample tubes,for example,P-20,P-80 or P-100,in that casethe amount of water has to be adjusted to ensure complete hydrolisation of UF6andavoid excessive heat evolution.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 States1 5.10 Copper wires,optional.The wires should be flexibleand looped at one end to loosely fit around the PCTFE tubewithout allowing the flare nut to pass through.5.11 Desiccator,optional.5.12 Balance,100-g capacity,readable to at least 0.1 mg,preferably 0.01 mg.NOTE2Use of a balance with lower sensitivity will negatively impacton sampling error.6.Interferences6.1 The weight of the PCTFE tube is affected by atmo-spheric humidity.Keep the P-10 tube assembly in a desiccatorbetween weighings until constant weight is attained.6.2 The capacity o