1、Designation:D 3442 91(Reapproved 1995)e1An American National StandardStandard Test Method forGaseous Tritium Content of the Atmosphere1This standard is issued under the fixed designation D 3442;the number immediately following the designation indicates the year oforiginal adoption or,in the case of
2、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.e1NOTEEditorial corrections were made to Sections 1 and 9 and Section 16 was added in August 1995.1.Scope1.1 Thi
3、s test method covers the measurement of total tritiumactivity in the atmosphere in concentrations greater than 74mBq/m3(2 pCi/m3).This test method covers sample collection,preparation,and radiometric assay of the sample.1.2 The values stated in SI units are to be regarded as thestandard.The values g
4、iven in parentheses are for informationonly.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
5、 limitations prior to use.2.Referenced Documents2.1 ASTM Standards:D 1071 Test Methods for Volumetric Measurement of Gas-eous Fuel Samples2D 1356 Terminology Relating to Sampling and Analysis ofAtmospheres3D 1357 Practice for Planning the Sampling of the AmbientAtmosphere3D 2476 Test Method for Trit
6、ium in Water4D 3195 Practice for Rotameter Calibration33.Terminology3.1 DefinitionsFor definitions of terms used in this testmethod,see Terminology D 1356.4.Summary of Test Method4.1 Air is pumped at a sampling rate of 100 to 500 mL/minthrough a tube furnace packed with palladium catalyst at atemper
7、ature of 500C or a copper oxide catalyst at a tempera-ture of 600 to 650C for approximately 1 week.Gaseoustritium present in the airstream is oxidized to form tritiatedwater vapor which is then adsorbed on silica gel with theambient water vapor.The water is distilled from the silica geland the triti
8、um activity is measured by liquid scintillationcounting.The volume of air sampled and the total volume ofwater vapor collected during the sampling period is determinedand the tritium activity of the atmosphere is calculated.4.2 Both the palladium and copper oxide catalysts havebeen found satisfactor
9、y for sampling where monitoring tritiumin the form of water,hydrogen gas,and heavy hydrocarboncompounds;however,the copper oxide catalyst has lowefficiency for oxidizing tritium in forms such as methane.5.Significance and Use5.1 This test method is useful for sampling the atmospherefor tritium activ
10、ity,in the form of tritiated hydrogen gas(HT orT2),water,methane,and other gaseous hydrocarbons,andgases that can be oxidized to form water.5.2 Tritiated particulate matter will not be collected andanalyzed.6.Interference6.1 Volatile radioactive particulates and radioiodine caninterfere and when the
11、y are expected they can be prefiltered bya charcoal cartridge or zeolite.Radioiodine and radioactiveparticulate matter can be filtered from the air prior to passingthrough the tube furnace.7.Apparatus7.1 Liquid Scintillation Counter.(See Test Method D 2476.)7.2 Tube Furnace(100 mm heating length;ran
12、ge 750C).7.3 Low-Volume Leakless Continuous Vacuum Pump,ca-pacity of 750 mL/min,with flow controller such as a limitingorifice.7.4 Tubes,glass or metal,30 to 50 mm in diameter and 250to 350 mm long.7.5 Temperature-Resisting Tubing,to hold catalyst insidetube furnace.7.6 Distillation Flask,1-L,with s
13、tandard-taper connectors.7.7 Condenser,with connectors to distillation flask,all“standard-taper”joints.7.8 Condensate Receiving Vessel,with standard-taper joint.7.9 Rubber Stoppers.1This test method is under the jurisdiction of ASTM Committee D-22 onSampling and Analysis of Atmospheres,and is the di
14、rect responsibility of Subcom-mittee D22.03 on Ambient Atmospheres and Source Emissions.Current edition approved Oct.15,1991.Published December 1991.Originallypublished as D 3442 75.Last previous edition D 3442 89.2Annual Book of ASTM Standards,Vol 05.05.3Annual Book of ASTM Standards,Vol 11.03.4Ann
15、ual Book of ASTM Standards,Vol 11.02.1Copyright ASTM,100 Barr Harbor Drive,West Conshohocken,PA 19428-2959,United States.NOTICE:This standard has either been superseded and replaced by a new version or discontinued.Contact ASTM International(www.astm.org)for the latest information.7.10 Vacuum Tubing
16、,to connect sampling system compo-nents.7.11 Vials,polyethylene(20-to 25-mL,for liquid scintilla-tion counting).(If sample is to be stored for any length of timeglass vials should be used.)See Test Method D 2476 forprecautions on type of glass.7.12 Heating Mantle and Temperature Controller.7.13 Charcoal Cartridge.7.14 Quartz Wool.7.15 Volume Meter,dry,diaphragm type.7.16 Rotameter,;750 mL/min.8.Reagents8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.All reagents shall con
