1、Designation: C 1408 98 (Reapproved 2004)Standard Test Method forCarbon (Total) in Uranium Oxide Powders and Pellets ByDirect Combustion-Infrared Detection Method1This standard is issued under the fixed designation C 1408; the number immediately following the designation indicates the year oforiginal
2、 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 covers the determination of carbon innuclear-grad
3、e uranium oxide powders and pellets to determinecompliance with specifications.1.2 Gadolinium oxide (Gd2O3) and gadolinium oxide-uranium oxide powders and pellets may also be analyzed usingthis test method.1.3 This test method covers the determination of 5 to 500 gof residual carbon.1.4 This test me
4、thod describes an induction furnace carriergas combustion system equipped with an infrared detector. Itmay also be applied to a similar instrument equipped with athermal conductivity detector.1.5 The preferred system of units is micrograms carbon pergram of sample (g/g sample) or micrograms carbon p
5、er gramof uranium (g/g U).1.6 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 pr
6、ior to use.2. Referenced Documents2.1 ASTM Standards:2C 753 Specification for Nuclear-Grade, Sinterable UraniumDioxide PowderC 776 Specification for Sintered Uranium Dioxide PelletsC 888 Specification for Nuclear-Grade Gadolinium Oxide(Gd2O3) PowderC 922 Specification for Sintered Gadolinium Oxide-U
7、ranium Dioxide Pellets3. Summary of Test Method3.1 The powered or crushed test specimen and an appropri-ate accelerator (metal flux) are added to a crucible, placedwithin an induction-heated furnace and burned at a nominaltemperature of 1600 to 1700C in a stream of oxygen. Acatalyst converts the car
8、bon monoxide (CO) to carbon dioxide(CO2) and the products of combustion are scavenged free ofsulfur compounds, halogens, and water vapor. The CO2isswept into an infrared cell detector. The amount of carbon isautomatically determined from stored calibration data, and isdisplayed or printed out, or bo
9、th, by the carbon analyzer.3.2 The actual configuration of the system may vary withvendor and model. Typical systems include columns of mate-rials such as copper oxide, platinized silica gel, magnesiumperchlorate, sodium hydroxide, and cellulose to purify the CO2stream.4. Significance and Use4.1 Ura
10、nium dioxide is used as a nuclear-reactor fuel.Gadolinium oxide is used as an additive to uranium dioxide. Inorder to be suitable for this purpose, these materials must meetcertain criteria for impurity content. This test method isdesigned to determine whether the carbon content meetsSpecifications
11、C 753, C 776, C 888, and C 922.5. Interferences5.1 Contamination of carrier gas, crucibles, or samples withextraneous sources of carbon may cause a positive bias. Theblank correction will help to minimize the bias from carrier gasand crucibles. Interference from absorbed carbon on samplesmay be elim
12、inated by keeping the sample in an inert atmo-sphere or vacuum.5.2 Powdered Gd2O3samples may adsorb CO/CO2from theatmosphere. Sample preheating to 120 for2hisrecom-mended in this case.1This test method is under the jurisdiction of ASTM Committee C26 on NuclearFuel Cycle and is the direct responsibil
13、ity of Subcommittee C26.05 on Methods ofTest.Current edition approved June 1, 2004. Published July 2004. Originally approvedin 1998. Last previous edition approved in 1998 as C 1408 - 98.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at servicea
14、stm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.3 The purification system typically associated with there
15、commended combustion and detection equipment is de-signed to minimize other expected sources of interferences,such as sulfur, halogens, and water.6. Apparatus6.1 Low-Carbon Analyzer, consisting of an induction-heated furnace suitable for operation at 1600 to 1700C, aninfrared detector for measuring
16、carbon dioxide, and auxiliarypurification systems.6.2 Crucibles, expendable alumina or similar refractorymaterial. Both the crucible and cover, if used, must bepre-ignited at a temperature of 1000C or higher for a timesufficient to produce constant blank values.6.3 Muffle Furnace, capable of attaini
17、ng temperature of1000C, for pre-igniting crucibles.6.4 Tongs and Forceps, for handling crucibles and lids.6.5 Stainless Steel Scoops and Spatulas7. Reagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagen
18、ts shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.3Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theac
19、curacy of the determination.7.2 AcceleratorsCopper metal, tin-tungsten mixture4,copper oxide, granular tin, and high purity iron chip accelera-tors for increased combustion temperature. These materials areavailable in appropriate purity and form from carbon analyzervendors. The criterion for satisfa
20、ctory results is the absence ofsignificant additional carbon release upon recombustion of thespecimen.7.3 Cellulose Trap PackingSurgical grade cotton orequivalent.7.4 Carbon Dioxide and Moisture AbsorbentsSodiumhydroxide (NaOH) on a fibrous support5and magnesiumperchlorate68. Carbon Standard Materia
21、ls8.1 NIST SRM steel standards or equivalent:8.1.1 The 101, 131, 133, 339, and 343 series, ranging fromapproximately 20 g/g sample to 1500 g/g sample have beenfound satisfactory.9. Hazards and Precautions9.1 Take proper safety precautions to prevent inhalation, oringestion of uranium dioxide powders
22、 or dust during grindingor handling operations.9.2 Operation of equipment presents electrical and thermalhazards. Follow manufacturer recommendations for safe op-eration.9.3 This procedure uses hazardous chemicals. Use appro-priate precautions for handling corrosives, oxidizers, andgases.10. Prepara
23、tion of Apparatus10.1 Change instrument column packing and reagents asrecommended by manufacturer.10.2 Set the operating controls of the instrument systemaccording to the operating instructions for the specific equip-ment used.10.3 Condition the apparatus by combustion of severalblanks prepared with
24、 sample crucible and accelerator in theamount to be used with the samples. Successive blanks shouldapproach a constant value, allowing for normal statisticalfluctuations.11. Calibration11.1 The calibration range and number of standards willdepend upon the instrument used. Two to four standardscontai
25、ning 50 to 600 g carbon are recommended.11.2 Add a volumetrically measured or weighed portion ofaccelerator and weighed portion of standard to a pre-ignitedsample crucible. (The amount of accelerator will depend uponthe instrument used and operating conditions.)11.3 Load and combust the standards ac
26、cording to themanufacturers recommended operating conditions.11.4 Calibrate the instrument according to operating instruc-tions. Calibration coefficients are normally stored in the mi-croprocessor memory.11.5 Recalibration frequency will depend upon the type ofinstrument used. As a minimum, recalibr
27、ation is required whencritical instrument components are changed, or when controlstandards data indicate that the instrument is failing to meetperformance criteria.12. Procedure12.1 Crush pellet samples to obtain approximately 1-mm(18 mesh) particles. (The particle size required may varyaccording to
28、 the instrument used and operating conditions.)12.2 Measure or weigh accelerator into a pre-ignited samplecrucible. (The amount of accelerator will depend upon theinstrument used and operating conditions.)3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washing
29、ton, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.4The sole so
30、urce of supply of the apparatus, Lecocel accelerator, known to thecommittee at this time is LECO Corporation. If you are aware of alternativesuppliers, please provide this information to ASTM Headquarters. Your commentswill receive careful consideration at a meeting of the responsible technicalcommi
31、ttee,1that you may attend.5The sole source of supply of the apparatus, ascarite, known to the committee atthis time is J.T. Baker, Inc. If you are aware of alternative suppliers, please providethis information to ASTM Headquarters. Your comments will receive carefulconsideration at a meeting of the
32、responsible technical committee,1that you mayattend.6The sole source of supply of the apparatus, anhydrone, known to the committeeat this time is J.T. Baker Inc. If you are aware of alternative suppliers, please providethis information to ASTM Headquarters. Your comments will receive carefulconsider
33、ation at a meeting of the responsible technical committee,1that you mayattend.C 1408 98 (2004)212.3 Weigh a portion of sample, (0.3 g to2gissuggested)to the nearest 0.01 g, into the crucible. The sample size shouldbe chosen to provide adequate sensitivity and accuracy at lowcarbon concentrations, bu
34、t should contain less than 200 g ofcarbon.12.4 Load the crucible into the induction furnace andcombust the sample according to the manufacturers recom-mended operating conditions. (Combustion time will vary withthe instrument used, but it is typically in the 30 to 120-s range.)Record the result.12.5
35、 Remove the sample crucible and examine it for incom-plete combustion. The crucible contents should be a uniformlyfused mass. Results from incompletely fused samples shall notbe accepted.13. Calculation13.1 Calculate the carbon content as follows:g C per g of sample 5 Cs2 Cb!/W (1)where:Cs= microgra
36、ms of carbon in test specimen,Cb= micrograms of carbon in a blank run, andW = grams of test specimen.13.2 For samples requiring carbon results expressed as gcarbon per g U, convert results to uranium basis as follows:C, g/g U basis 5C g/g 3 100% U content of sample(2)14. Precision and Bias14.1 The p
37、recision and bias for this test method will dependupon the instrument used and the operating conditions.14.2 The relative standard deviation for a NIST 101G steelstandard (136 g/g) analyzed on the same instrument was3.4 %. The bias, as measured by percent recovery of thestandards value, was +1.4 %.
38、These data represent 45 stan-dards collected by multiple operators using one instrument,over a one-year period.14.3 The relative standard deviation for a 36 g/g workinguranium oxide powder standard analyzed at one laboratory was8.0 %. The bias, as measured by percent recovery of thestandards value,
39、was +7.0 %. These data represent 214 stan-dards measured by multiple operators using one instrument,over a one-year period.15. Keywords15.1 carbon content; gadolinium oxide; gadolinium oxide-uranium oxide; impurity content; uranium oxideASTM International takes no position respecting the validity of
40、 any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to
41、revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Y
42、our comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is co
43、pyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).C 1408 98 (2004)3
