1、Designation: D 3803 91 (Reapproved 2004)Standard Test Method forNuclear-Grade Activated Carbon1This standard is issued under the fixed designation D 3803; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A
2、 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 a very stringent procedure forestablishing the capability of new and used activated carbon toremove radio-labeled
3、 methyl iodide from air and gas streams.The single test method described is for application to both newand used carbons, and should give test results comparable tothose obtained from similar tests required and performedthroughout the world. The conditions employed were selectedto approximate operati
4、ng or accident conditions of a nuclearreactor which would severely reduce the performance ofactivated carbons. Increasing the temperature at which this testis performed generally increases the removal efficiency of thecarbon by increasing the rate of chemical and physical absorp-tion and isotopic ex
5、change, that is, increasing the kinetics ofthe radioiodine removal mechanisms. Decreasing the relativehumidity of the test generally increases the efficiency of methyliodide removal by activated carbon. The water vapor competeswith the methyl iodide for adsorption sites on the carbon, andas the amou
6、nt of water vapor decreases with lower specifiedrelative humidities, the easier it is for the methyl iodide to beadsorbed. Therefore, this test method is a very stringent test ofnuclear-grade activated carbon because of the low temperatureand high relative humidity specified. This test method isreco
7、mmended for the qualification of new carbons and thequantification of the degradation of used carbons.1.1.1 Guidance for testing new and used carbons usingconditions different from this test method is offered in AnnexA1.1.2 This standard does not purport to address all of thesafety concerns, if any,
8、 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:2D 1193 Specification for Reagent WaterD 2652 Termino
9、logy Relating to Activated CarbonD 2854 Test Method for Apparent Density of ActivatedCarbonE 300 Practice for Sampling Industrial ChemicalsE 691 Practice for Conducting an Interlaboratory Test Studyto Determine Precision of a Test Method2.2 Code of Federal Regulations:CFR Title 49, Section 173.34, “
10、Qualification, Maintenance,and Use of Cylinders3CFR Title 49, Part 178, Subpart C, “Specifications forCylinders32.3 Military Standards:MIL-F-51068D Filter, Particulate High Efficiency, Fire Re-sistant4MIL-F-51079A Filter, Medium Fire Resistant, High Effi-ciency4MIL-STD-45662 Calibration Systems Requ
11、irements42.4 Other Standards:ANSI/ASME N45.2.6 Qualifications of Inspection, Exami-nation, and Testing Personnel for Nuclear Power Plants53. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 counter effciency (CE)the fraction of the actualnumber of disintegrations of a radioactive
12、sample that isrecorded by a nuclear counter.3.1.2 effciency (E)the percentage of the contaminantremoved from a gas stream by an adsorption bed; expressedmathematically as E = 100 P, where E and P are given inpercent.1This test method is under the jurisdiction of ASTM Committee D28 onActivated Carbon
13、 and is the direct responsibility of Subcommittee D28.04 on GasPhase Evaluation Tests.Current edition approved April 1, 2004. Published June 2004. Originallyapproved in 1979. Last previous edition approved in 1998 as D 3803 91 (1998).2For referenced ASTM standards, visit the ASTM website, www.astm.o
14、rg, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Published by the General Service Administration, 18th and “F St., N. W.,Washington, DC 20405.4Available from Standardization D
15、ocuments Order Desk, Bldg. 4 Section D, 700Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.5Available from American National Standards Institute, 11 W. 42nd St., 13thFloor, New York, NY 10036.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,
16、United States.3.1.3 penetration (P)the percentage of the contaminant(CH3I) which passes through the equilibrated test bed ofstandard depth, and is collected on the backup beds during thefeed and elution periods under specified conditions.3.1.4 relative humidity (RH)for the purpose of this testmethod
17、, relative humidity is defined as the ratio of the partialpressure of water in the gas to the saturation vapor pressure ofwater at the gas temperature and pressure. At temperaturesbelow 100C, this is the normal definition and relative humid-ity can range from 0 to 100 %.3.2 Definitionsfor additional
18、 terms relating to this stan-dard, see Terminology D 2652.4. Summary of Test Method4.1 Both new and used carbons are first exposed to humidair (pressure, approximately 1 atm; temperature, 30.0C; rela-tive humidity, 95 %) for a pre-equilibration period of 16 h.During this pre-equilibration period, th
19、e test system may be rununattended with the required parameter monitoring and ad-equate control devices. Following pre-equilibration, the airflow is continued for a two-hour equilibration period, duringwhich the acceptable variability of all parameters is reduced.The test system must be closely moni
20、tored and controlledduring the final four hours of the test. Qualification ofpersonnel to perform this testing must meet or exceed ANSI/ASME N 45.2.61978, Level II, which requires a combina-tion of education and actual test system operation experience.During the challenge or feed period, radio-label
21、ed methyliodide at a mass concentration of 1.75 mg/m3of humid airflow is passed through the beds for a period of 60 min.Following the feed period, humid air flow without test adsor-bate is continued at the same conditions for a 60-min elutionperiod. Throughout the entire test, the effluent from the
22、samplebed passes through two backup beds containing carbon havinga known high efficiency for methyl iodide. The two backupbeds trap essentially all the radio-labeled methyl iodide thatpasses the test bed and provide a differential indication of theirefficiency. At the end of the elution period, the
23、gamma activityof131I in the test and backup beds is measured by a gammacounter, and the percent of adsorbate penetrating the test bed isdetermined.5. Significance and Use5.1 The results of this test method give a conservativeestimate of the performance of nuclear-grade activated carbonused in all nu
24、clear power plant HVAC systems for the removalof radioiodine.6. Apparatus6.1 Sample Preparation Apparatus:6.1.1 Riffle Sampler, in accordance with 32.5.2 of PracticeE 300.6.1.2 Feed Funnel and Vibrator, in accordance with theProcedure Section of Test Method D 2854.6.2 Sample and Backup Bed Assemblie
25、s:6.2.1 The sample bed canister and backup bed canistersmust each be either a single unit capable of containing carbonto a depth of 50 6 1 mm, or they may be assembled from twoseparate units each capable of containing carbon to a depth of25 mm. Two backup canisters, each of 50 6 1 mm total depth,are
26、 required. Canisters may be reused after being decontami-nated to remove residual radioactivity. An acceptable bedconstruction is shown in Fig. 1 with critical dimensions noted.6.2.2 Clamping assemblies are needed for sample andbackup beds. The only requirements for these assemblies arethat they pro
27、vide a smooth sealing face, uniform alignment ofbed canisters, and sufficient clamping force so that the leak testin 10.2 can be met. A suggested design for clamping assembliesis shown in Fig. 2.6.3 A schematic of a generalized test system is shown inFig. 3. This system is designed to operate at app
28、roximately30C and 95 % relative humidity, with a gas flow of 24.7 L/minat atmospheric pressure. If test conditions which differ signifi-cantly from these are required, then separate calibrations orinstrumentation, or both, may be required.* Standard canister dimension may be used in multiples if des
29、ired.Single test canisters of full depth may be used.1Bed holder2Adsorption media3O-ring gland4Perforated screen (both ends)5Retaining snap ring (both ends)6Baffle (both ends)7Holes for assembly tie-rods (four)FIG. 1 Adsorption Media Test Bed Holder (Canister)D 3803 91 (2004)26.4 Saturator SystemThi
30、s system may be a controlledtemperature saturator (bubbler) or spray chamber (environmen-tal condition generator), or any other device of sufficientstability and capacity to supply the required mass flow of watervapor at test conditions.6.5 Flow GeneratorThis system may be an air compres-sor upstrea
31、m of the test system or a vacuum pump downstreamof the test system. A dryer, carbon adsorber, and HEPA(high-efficiency particulate air) filter are required for eithersystem to condition the inlet air. Flow measurement andcontrol should be accurate and stable to within 6 2% ofspecified flow rate. Sys
32、tem capacity shall meet or exceed thevolumetric flow requirements as calculated from the specifiedface velocity. A surge tank and pressure control valve should beemployed in either type of system to ensure stable and accurateflow measurement and control. For safety, it is important thatthe pressure
33、system be equipped with a pressure relief valve. Itis important that the pipe diameter and inlet air filters for avacuum system be designed and maintained to minimize thepressure drop from ambient to ensure that the specifications forabsolute pressure at the test bed are met (see Table 1).6.6 Moistu
34、re SeparatorA moisture separator should beused to protect the HEPA filter by removing large quantities ofentrained particulate water, if present, after humidification. AHEPA filter (or equivalent) is required to function as a finaldroplet trap to remove small amounts of fine particulate waterfrom th
35、e carrier gas ahead of the test bed.6.7 Adsorbate SupplyThis system shall consist of a stain-less steel cylinder, pressure gage, pressure regulator, and a flowregulator capable of providing a steady flow of the challengegas, that is, radio-labeled methyl iodide in dry nitrogen, for theduration of th
36、e test feed period. The point of injection into themain gas flow of the system must be such that the cross-sectional distribution of the adsorbate at the face of the test bedcan be ensured to be homogeneous. A mixing chamber, baffles,glass beads, etc. should be used to achieve adequate mixing.6.8 Co
37、nstant Temperature CabinetAn enclosure and as-sociated thermoregulatory system must be used that is capableof maintaining the inlet gas stream temperature from the pointof humidity control to the test bed, and the surface temperatureof all carbon canisters at 30.0 6 0.2C, except during the firstseve
38、ral hours of pre-equilibration, during which the adsorptionof water by the carbons may increase these temperaturesslightly. All tubing downstream of the moisture separator, thecarbon bed canisters and holders, temperature and pressureports and measurement devices upstream and downstream ofthe test b
39、ed, and an upstream port and tubing to the dew pointsensor all must be included within the temperature controlledenclosure. In addition, it is highly recommended that a bypassline be included around the sample bed assembly to avoidexposing the sample to start-up conditions possibly outsidethose spec
40、ified.6.9 Flow Measurement and ControlMass flow control-lers, control valve and orifice meter, rotameter or any otherdevice with adequate stability and demonstrated measurementsystem accuracy of 6 2 % of specified flow rate at the testconditions. All flow measuring devices must use correctionfactors
41、 for interpretation and application to actual test condi-tions. These factors must be carefully predetermined anddocumented. No flow measuring device should be locateddirectly downstream of the test bed such that it is subject tovariable temperature and humidity conditions during a test as aresult o
42、f water absorption by the carbon.6.10 Interconnecting TubingTubing must be non-reactivewith methyl iodide, such as stainless steel, glass, etc., with aminimum of38-in. outside diameter, and kept as short aspossible to reduce the system pressure drop.1Canister (four shown)2Inlet cap3Outlet cap4Thermo
43、couple5Thermocouple fitting6Static tap7Tie bar (four)8O-ring sealsFIG. 2 Canister Assembly (Test or Backup Beds)D 3803 91 (2004)36.11 Temperature Measurement Devices Platinum resis-tance thermometers (RTDs) with certified accuracy and mea-surement system calibration to 6 0.2C are required for themea
44、surement of test bed inlet air temperature and dew point.The placement of the air temperature RTD must be such that itis not subject to radiative heating from the test bed. It is criticalto the exact measurement of relative humidity that the chilledmirror RTD and the inlet air temperature RTD be mat
45、chedexactly (6 0.1C) or that differences are exactly corrected forin relative humidity calculations.6.12 Pressure Measurement DevicesAbsolute pressuremeasuring devices must be accurate to within 6 1 % of thereading at standard atmospheric pressure and be capable ofdigital or analog output to meet th
46、e specified recordingrequirements. The sensors and output devices must be cali-brated as a unit to ensure system accuracy. The differentialpressure device required for measurements across the test bedmust be capable of detecting a 0.25 kPa pressure difference andbe accurate to within 6 2 % of the re
47、ading at the normaloperating differential pressure.6.13 Humidity MeasurementA humidity measuring de-vice with demonstrated accuracy and calibration to 6 0.2C at30C and 95 % relative humidity is required for measurementof relative humidity of the gas stream immediately upstream ofthe test bed. Note t
48、hat for these test conditions only an opticaldew point hygrometer currently meets these specifications. Asecondary check on this measurement device is required toensure that calibration offset has not occurred. This secondarydevice may be another optical dew point hygrometer, wetFIG. 3 Schematic of
49、Activated Carbon Test SystemTABLE 1 Parameter SpecificationsNOTE 1Temperature, relative humidity, pressure, and gas velocity areto remain constant within the specified maximum variations throughoutthe entire test, that is, for each test period. Parameter excursions outsidethe limits specified in this table will invalidate the test results. If resultsbased on a test containing such variations must be reported, then thesevariations must be noted in the comments section of the external reportform and flagged in the parameter monitorin
