ASTM C1441-2013 Standard Test Method for the Analysis of Refrigerant 114 Plus Other Carbon-Containing and Fluorine-Containing Compounds in Uranium Hexafluoride via Fourier-Transfor.pdf

1、Designation: C1441 13Standard Test Method forThe Analysis of Refrigerant 114, Plus Other Carbon-Containing and Fluorine-Containing Compounds in UraniumHexafluoride via Fourier-Transform Infrared (FTIR)Spectroscopy1This standard is issued under the fixed designation C1441; the number immediately foll

2、owing 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

3、 covers determining the concentrationsof refrigerant-114, some other carbon-containing and fluorine-containing compounds, hydrocarbons, and partially or com-pletely substituted halohydrocarbons that may be impurities inuranium hexafluoride when looked for specifically. The twooptions are outlined fo

4、r this test method. They are designatedas Part A and Part B.1.1.1 To provide instructions for performing Fourier-Transform Infrared (FTIR) spectroscopic analysis for thepossible presence of Refrigerant-114 impurity in a gaseoussample of uranium hexafluoride, collected in a “2S” containeror equivalen

5、t at room temperature. The all gas procedureapplies to the analysis of possible Refrigerant-114 impurity inuranium hexafluoride, and to the gas manifold system used forFTIR applications. The pressure and temperatures must becontrolled to maintain a gaseous sample. The concentrationunits are in mole

6、percent. This is Part A.1.2 The method discribed in part B is more efficient becausethere isnt matrix effect. FTIR spectroscopy identifies bonds asC-H, C-F, C-Cl. To quantify HCH compounds, these com-pounds must be known and the standards available to do thecalibration.After a screening, if the spec

7、trum is the UF6spectrum or ifthe other absorption peaks allow the HCH quantification, thistest method can be used to check the compliance of UF6asspecified in Specifications C787 and C996. The limits ofdetection are in units of mole percent concentration.1.3 Part A pertains to Sections 7-10and Part

8、B pertains toSections 12-16.1.4 These test options are applicable to the determination ofhydrocarbons, chlorocarbons, and partially or completely sub-stituted halohydrocarbons contained as impurities in uraniumhexafluoride (UF6). Gases such as carbon tetrafluoride (CF4),which absorb infrared radiati

9、on in a region where uraniumhexafluoride also absorbs infrared radiation, cannot be ana-lyzed in low concentration via these methods due to spectraloverlap/interference.1.5 These test options are quantitative and applicable in theconcentration ranges from 0.003 to 0.100 mole percent, de-pending on t

10、he analyte.1.6 These test methods can also be used for the determina-tion of non-metallic fluorides such as silicon tetrafluoride(SiF4), phosphorus pentafluoride (PF5), boron trifluoride (BF3),and hydrofluoric acid (HF), plus metal-containing fluoridessuch as molybdenum hexafluoride (MoF6). The avai

11、lability ofhigh quality standards for these gases is necessary for quanti-tative analysis.1.7 These methods can be extended to other carbon-containing and inorganic gases as long as:1.7.1 There are not any spectral interferences from uraniumhexafluorides infrared absorbances.1.7.2 There shall be a k

12、nown calibration or known “K”(values) for these other gases.1.8 The values stated in SI units are to be regarded as thestandard.1.9 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

13、appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C761 Test Methods for Chemical, Mass Spectrometric,Spectrochemical, Nuclear, and RadiochemicalAnalysis of1This test method is under the jurisdic

14、tion ofASTM Committee C26 on Methodsof Test.Current edition approved April 1, 2013. Published July 2013 Originally approvedin 1999. Last previous edition approved in 2004 as C144104, which waswithdrawn in January 2013 and reinstated in April 2013. DOI: 10.1520/C1441-13.2For referenced ASTM standards

15、, 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 194

16、28-2959. United States1Uranium HexafluorideC787 Specification for Uranium Hexafluoride for Enrich-mentC859 Terminology Relating to Nuclear MaterialsC996 Specification for Uranium Hexafluoride Enriched toLess Than 5 %235UC1052 Practice for Bulk Sampling of Liquid UraniumHexafluoride2.2 USEC DocumentU

17、SEC-651 Uranium Hexafluoride: A Manual of Good Han-dling Practices33. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 detection limit, nbased on the minimum absorbanceobtainable at a given pressure to yield a meaningful result inaccordance with Eq 2. In accordance with Terminolog

18、y C859,a low concentration level that can be achieved with thesemethods is 0.003 mol percent at the 95 % confidence level.3.1.2 FTIR, nFourier-transform infrared spectroscopy.3.1.3 K, ninfrared absorbance constant in pressure units,where:K 5mole percent concentration standard pressure!absorbance(1)3

19、.1.4 “2S” container, na nickel container with a 1.0 Lcapacity.4. Summary of Test Methods4.1 Part A is based on the collection of an all gas sample ofUF6. The gas sample is then analyzed at room temperature viaFTIR to determine the percent Refrigerant-114 in uraniumhexafluoride.4.2 Part B is based on

20、 the collection of an all gas sample ofUF6. There are two differences with the Part A:the calibration is performed in UF6.the path length used is 5 meters equipped with zincselenide (ZnSe) optics.4.3 In Parts A and B, the pressure is kept low enough sothat the manifold and sample cell are filled onl

21、y with gaseousUF6.5. Significance and Use5.1 This test method (Part A) utilizes FTIR spectroscopy todetermine the percent Refrigerant-114 impurity in uraniumhexafluoride. Refrigerant-114 is an example of an impurity gasin uranium hexafluoride.6. Hazards6.1 Uranium hexafluoride is considered to be a

22、hazardousmaterial. It is a highly reactive and toxic substance in additionto its radioactive properties. It must be handled as a gas innickel containers and well-conditioned nickel manifolds toensure safety. Suitable handling procedures are described inUSEC-651.7. Apparatus (Part A)7.1 Fourier-Trans

23、form Infrared Spectrophotometer, or dis-persive infrared spectrophotometer set up to collect data in therange 4000 to 400 cm1with 6 2cm1resolution or better.7.2 A Manifold System, built with materials of constructioninert to fluorine-bearing gases. The manifold system shall beconditioned and passiva

24、ted with an appropriate fluorinatingagent. (See Annex A2.)7.3 A Nickel Sample Cell equipped with silver chloridewindows. The pathlength used in these experiments is 10 cm(0.1m).7.4 A Pressure Gage, which can be read to 1 Pa is necessary.7.5 Absorbance Data, can be determined to 0.001 units.8. Calibr

25、ation (Part A)8.1 The infrared spectrophotometer is calibration checkeddaily with a traceable standard of Refrigerant-114. The re-sponse of the instrument and the sensitivity of the pressuremanometers can be evaluated based on the mole percentconcentration Refrigerant-114 calculated. See Table 1 for

26、absorbance maxima and corresponding “K” values.8.2 The operating experience of each laboratory for preci-sion calculations of the mole percent concentrations of uraniumhexafluoride and impurities are critical to the success of themethod. Total pressure should be maintained at 100 mm HgA(13.3 kPa) or

27、 less. Each laboratory shall determine the “K”values specific to its instrumentation.8.3 The “K” values used for calibrations are good wellbeyond the 60 to 75 mm HgA (8 to 10 kPa) in a typical all gassample.8.4 The “K” values require that the mole percent concen-tration of a traceable standard, pres

28、sure, and absorbance of apure gas are known. The response of absorbance as a functionof pressure is linear. The slope of this line is “K.” The slope isconstant from near zero absorbance to about 0.8 absorbanceunits.9. Procedure (Part A)9.1 Collecting the SampleAn all gas sample is collectedfrom the

29、apparatus described in Test Method C761. See AnnexA1 or Fig. 1 in Test Method C761. The isotope abundancesample tube is replaced by a “2S” container. The valve on theinverted liquid uranium hexafluoride container is closed whenthe pressure on the manometer reads 75 mm HgA (10 kPa). A3Available from

30、USEC Inc., 6903 Rockledge Drive, Bethesda, MD 20817.TABLE 1 Typical Infrared Active Gas Molecules, TheirApproximate Infrared Frequencies in cm1, and Their InfraredAbsorbance Constants (K) in mm Part A, Determined at RoomTemperature (25C=77F=298K)Infrared Active Gas MoleculeApproximate InfraredFreque

31、ncy in cm1KinkPaUranium Hexafluoride = UF6625 11Uranium Hexafluoride = UF6676 1.6Refrigerant-114 = C2F4Cl2922 93.2Refrigerant-114 = C2F4Cl21052 70.1Refrigerant-114 = C2F4Cl21185 48.4Refrigerant-114a = C2F4Cl21231 32.1C1441 132total of three samples are obtained in this manner. If threesample contain

32、ers (“2S” or equivalent) are not available, threegas charges from one sample can be substituted. However, ifthe full pressure in the sample container is less than 50 mmHgA (6.7 kPa), the three gas charges from one sample optionis not recommended.NOTE 1The manifold system must be conditioned and pass

33、ivated withan appropriate fluorinating agent to generate high quality analyticalresults.9.2 Acquire Background Scan (Refer to Annex A2):NOTE 2The vacuum manometer Valve C must be open in order forpressure in mm to be read.9.2.1 Ensure that the cold trap inlet valve (L) and crossovervalves (MX1 and M

34、X2) are closed.9.2.2 Ensure that the chem trap outlet (R), chem trap inlet(Y), sample cell inlet (A), vacuum pump inlet (P), and sampleport (S1, S2, or S3) valves are open.9.2.3 Ensure that all other valves other than Valve C areclosed.9.2.4 Evacuate manifold system until readout on thermo-couple ga

35、ge (T2) displays a value of less than 10 m.9.2.5 Verify the digital manometer for zero and full scalereadings, if not adjust accordingly.9.2.6 Obtain an infrared background spectrum on the FTIR.9.3 Acquire Initial Sample Scan:9.3.1 Close chem trap inlet valve (Y).9.3.2 Open the sample container valv

36、e and charge themanifold with the full contents of the sample container.NOTE 3If the total pressure of the sample is in excess of 13 kPa, aresample is desirable.9.3.3 Close the sample container valve.9.3.4 Obtain the infrared spectrum of the gases in thesample charge.9.4 Interpret Spectrum:9.4.1 Rec

37、ord the absorbance maxima for the threeRefrigerant-114 bands cited in Table 1, if any are present. Theabsorbance maximum at 1052 cm1typically experiences theleast amount of overlap.9.4.2 Record the absorbance maximum for Refrigerant-114afrom Table 1, if any is present.9.4.3 Record the absorbance max

38、imum for uraniumhexafluoride at 676 cm1.9.4.4 Record the pressure (in mm) from the readout of thedigital manometer (C). (If the pressure exceeds 13 kPa resam-pling is necessary due to the possibility of freeze-out of theUF6.)9.4.5 Monitor the absorbance of uranium hexafluoride at625 cm1of the full p

39、ressure gas charge.9.4.5.1 If the absorbance at full pressure exceeds 0.8 unitspartial evacuation of the manifold is necessary in accordancewith the action steps in 9.5.9.4.5.2 If the absorbance at full pressure is less than 0.8units, a resample is desirable.9.5 Partial Evacuation of the Manifold Sy

40、stem:9.5.1 Close the chem trap outlet valve (R).9.5.2 Open the chem trap inlet valve (Y).9.5.3 Close the chem trap inlet valve (Y) when the pressureon the digital manometer is no longer decreasing.9.5.4 Allow a minimum of 30 s residency time in the chemtrap (E).9.5.5 Open the chem trap outlet valve

41、(R) to vent anyremaining gases to the always energized vacuum pump (W).9.5.6 Close the chem trap outlet valve (R) when the readouton the thermocouple gage (T2) is less than 1 Pa.9.5.7 Repeat step 9.5.1-9.5.6, until the pressure on thedigital manometer reads 0.1 kPa.9.6 Scanning the Sample for Uraniu

42、m Hexafluoride at 625cm1:9.6.1 Scan the sample for uranium hexafluoride at a pressurethat results in an infrared peak less than 0.80 absorbance units.9.6.2 Record the magnitude of the absorbance maximum forthe uranium hexafluoride peak at 625 cm1.9.6.3 Record the pressure (in mm) from the readout of

43、 thedigital manometer for the uranium hexafluoride peak at 625cm1.NOTE 4If the pressure required to obtain an absorbance less than 0.8units at 625 cm1is less than 0.40 mm HgA, the values obtained at 676cm1are likely to be more reliable.9.7 Total Evacuation of the Manifold System:9.7.1 Repeat the act

44、ion steps in 9.5 until the pressure on thedigital manometer reads 0.20 mm HgA or less.9.7.2 Open the cold trap inlet valve (L) and at least one ofthe crossover valves (MX1 or MX2).9.7.3 Continue the total evacuation until the thermocouplegauge (T2) reads below 1 Pa and the digital manometer reads0 P

45、a.9.7.4 Rezero the digital manometer if the readout stabilizesfor 2 min at a reading other than 0 Pa.9.8 Replicate Experiments:9.8.1 Proceed to Section 10 if the three gas changes fromone sample was used in 9.1.9.8.2 Repeat action steps 9.3-9.7.4 twice more, using a freshreplicate sample from the th

46、ree “2S” containers received.10. Calculations of Mole Percent Concentrations (Part A)10.1 Calculate the average mole percent concentrations ofRefrigerant-114 and Refrigerant-114a based on their respectiveabsorbances, the “K” values, and the total pressure in themanifold as indicated in Eq 2:NOTE 5If

47、 the uranium hexafluoride concentration is high, based onthe data obtained from the measurements at 625 cm1, the uraniumhexafluoride band at 1157 cm1may interfere with the Refrigerant-114band at 1185 cm1. The Refrigerant-114 concentration may be biased highshould this result be included with the dat

48、a obtained at 922 cm1and 1052cm1.mole percent concentration 5absorbance!K!total pressure(2)10.2 Calculate mole percent concentration for uraniumhexafluoride based on the absorbance at 625 or 676 cm1, theappropriate “K” value, and the total pressure in the manifold asindicated in Eq 2.C1441 13310.3 D

49、etermination of the mean mole percent concentra-tions of Refrigerant-114 and UF6plus the percent concentra-tion Refrigerant-114 in UF6.10.3.1 Calculate the mean mole percent concentrations ofboth Refrigerant-114 and Refrigerant-114a in accordance with10.1 if any is present, using each of the indicated absorbancefrequencies listed in Table 1. This result is based on the threegas charges from one sample or three replicate samples.10.3.2 Sum the mean mole percent concentrations ofRefrigerant-114 and Refrigerant-114A and record as totalRefrigeran