1、 Reference numberISO 22875:2008(E)ISO 2008INTERNATIONAL STANDARD ISO22875First edition2008-01-15Nuclear energy Determination of chlorine and fluorine in uranium dioxide powder and sintered pellets nergie nuclaire Dtermination du chlore et du fluor dans les poudres de dioxyde duranium et les pastille
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7、08 All rights reserved iiiContents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references . 1 3 Principle. 1 4 Reagents 1 5 Apparatus 3 6 Procedure 4 7 Test report . 9 Bibliography . 10 ISO 22875:2008(E) iv ISO 2008 All rights reservedForeword ISO (the International Organization for Stan
8、dardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right
9、 to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International S
10、tandards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an
11、International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 22
12、875 was prepared by Technical Committee ISO/TC 85, Nuclear energy, Subcommittee SC 5, Nuclear fuel technology. ISO 22875:2008(E) ISO 2008 All rights reserved vIntroduction This International Standard describes a method for determining the chlorine and fluorine concentrations in uranium dioxide and i
13、n sintered fuel pellets by pyrohydrolysis of samples, followed either by liquid ion-exchange chromatography or by selective electrode measurement of chlorine and fluorine ions. Many ion-exchange chromatography systems and ion-selective electrode measurement systems are available; the equipment and o
14、perating procedure are, therefore, not described in detail. INTERNATIONAL STANDARD ISO 22875:2008(E) ISO 2008 All rights reserved 1Nuclear energy Determination of chlorine and fluorine in uranium dioxide powder and sintered pellets 1 Scope This International Standard describes a method for determini
15、ng chlorine and fluorine in uranium dioxide powder and sintered pellets. It is applicable for the analysis of samples with a mass fraction of chlorine from 5 g/g to 500 g/g and with a mass fraction of fluorine from 2 g/g to 500 g/g. 2 Normative references ISO 3696, Water for analytical laboratory us
16、e Specification and test methods ISO 9892:1992, Uranium metal, uranium dioxide powder and pellets, and uranyl nitrate solutions Determination of fluorine content Fluoride ion selective electrode method 3 Principle The samples are pyrohydrolysed at 900 C to 1 000 C in a tubular furnace with wet air o
17、r steam heated to the same temperature. Chlorine and fluorine are trapped as halogenated acids and entrained in an aqueous solution. Two measurement methods may be used to measure the chlorine and fluorine ions: a) liquid ion-exchange chromatography; b) selective electrode measurement. 4 Reagents Us
18、e reagents of recognized analytical grade. 4.1 Water, complying with at least grade 1 in accordance with ISO 3696. 4.2 Anhydrous sodium chloride (NaCl). 4.3 Anhydrous sodium fluoride (NaF). 4.4 Sodium carbonate (Na2CO3). 4.5 Anhydrous sodium bicarbonate (NaHCO3). 4.6 Glacial acetic acid (CH3COOH), (
19、CH3COOH) = 1,06 g/ml. 4.7 Potassium acetate (CH3COOK). ISO 22875:2008(E) 2 ISO 2008 All rights reserved4.8 Concentrated eluant solution, c(Na2CO3) = 0,018 mol/l and c(NaHCO3) = 0,017 mol/l. Dissolve 1,908 g of Na2CO3(4.4) and 1,428 g of NaHCO3(4.5) in water (4.1). Pour into a 1 l volumetric flask. D
20、ilute to 1 l with water (4.1). Homogenize. 4.9 Standard eluant solution, Add 100 ml of concentrated eluant solution (4.8) to a 1 l volumetric flask. Dilute to 1 l with water (4.1). Homogenize. 4.10 Make-up eluant solution, c(Na2CO3) = 0,09 mol/l and c(NaHCO3) = 0,085 mol/l. Dissolve 9,540 g of Na2CO
21、3(4.4) and 7,140 g of NaHCO3(4.5) in water (4.1) Pour into a 1 l volumetric flask. Dilute to 1 l with water (4.1). Homogenize. 4.11 Buffer solution, c(CH3COOH) = 0,005 mol/l and c(CH3COOK) = 0,005 mol/l. Pour 250 l of acetic acid (4.6) and 0,50 g of potassium acetate (4.7) into a 1 l polyethylene vo
22、lumetric flask. Dilute to 1 l with water (4.1). Homogenize. The concentration of the buffer solution can alternatively be chosen between 0,001 mol/l and 0,1 mol/l. 4.12 Chloride reference solution, (Cl) = 1 g/l. Dissolve 1,648 g of dry anhydrous sodium chloride (4.2) in water (4.1). Pour into a 1 l
23、volumetric flask. Dilute to 1 l with water (4.1). Homogenize. To achieve dry sodium salt, heat at 120 C for 4 h just before use and keep in exicator. 4.13 Chloride reference solution, (Cl) = 0,1 g/l. Pipette 10 ml reference solution (4.12) into a 100 ml volumetric flask. Dilute to 100 ml with water
24、(4.1). Homogenize. 4.14 Chloride reference solution, (Cl) = 0,01 g/l. Pipette 10 ml reference solution (4.13) into a 100 ml volumetric flask. Dilute to 100 ml with water (4.1) Homogenize. Solutions may be stored for two months. 4.15 Fluoride reference solution, (F) = 1 g/l. Dissolve 2,210 0,001 g of
25、 dry anhydrous sodium fluoride (4.3) in water (4.1). Pour into a 1 l volumetric flask. Dilute to 1 l with water (4.1). Homogenize. To achieve dry sodium salt, heat at 120 C for 4 h just before use and keep in a desiccator. 4.16 Fluoride reference solution, (F) = 0,1 g/l. Pipette 10 ml reference solu
26、tion (4.15) into a 100 ml volumetric flask. Dilute to 100 ml with water (4.1). Homogenize. 4.17 Fluoride reference solution, (F) = 0,01 g/l. Pipette 10 ml reference solution (4.16) into a 100 ml flask. Dilute to 100 ml with water (4.1). Homogenize. Solutions may be stored for two months. 4.18 Chlori
27、de and fluoride calibration standard solutions for chromatography, (Cl) = 0,2 mg/l; (Cl) = 0,5 mg/l; (Cl) = 1,0 mg/l; (F) = 0,2 mg/l; (F) = 0,5 mg/l; (F) = 1,0 mg/l. ISO 22875:2008(E) ISO 2008 All rights reserved 3Into three 100 ml volumetric flasks, pipette quantities (2 ml, 5 ml and 10 ml respecti
28、vely) of the 0,01 g/l chloride reference solution (4.14) and the 0,01 g/l fluoride reference solution (4.17). Add 2 ml of concentrated eluant solution (4.8) to each flask. Dilute to 100 ml with water (4.1). Homogenize. These solutions now contain 0,2 mg/l, 0,5 mg/l and 1,0 mg/l, respectively, of chl
29、oride and fluoride ions. Prepare the calibration solutions fresh on the day of use. 4.19 Chloride calibration standard solutions for ion analysis, (Cl) = 0,5 mg/l; (Cl) = 1,0 mg/l; (Cl) = 2,0 mg/l. Into three 100 ml volumetric flasks, pipette quantities (5 ml, 10 ml and 20 ml) of the 0,01 g/l chlori
30、de reference solution (4.14). Add 20 ml of buffer solution (4.11). Dilute to 100 ml with water (4.1). Homogenize. These solutions now contain 0,5 mg/l, 1,0 mg/l and 2,0 mg/l, respectively, of chloride ions. Prepare the calibration solutions fresh on the day of use. 4.20 Fluoride calibration standard
31、 solutions for ion analysis, (F) = 0,5 mg/l; (F) = 1,0 mg/l; (F) = 2,0 mg/l. Pipette 5 ml, 10 ml and 20 ml of the 0,01 g/l fluoride reference solution (4.17) into three 100 ml volumetric flasks. Add 20 ml of buffer solution (4.11). Dilute to 100 ml with water (4.1). Homogenize. These solutions now c
32、ontain 0,5 mg/l, 1,0 mg/l and 2,0 mg/l, respectively, of fluoride ions. Prepare the calibration solutions fresh on the day of use. 5 Apparatus 5.1 Standard laboratory equipment. 5.2 Pyrohydrolysis apparatus. 5.2.1 Tubular furnace, equipped with a calibrated temperature regulator. 5.2.2 Tube with ste
33、am heater and condenser. The tube (Inconel1), platinum or quartz) in the furnace is 400 mm long and 20 mm in diameter. The diameter of the junction tube is 5 mm. In the case of a pyrohydrolysis device with steam heating, the junction tube is wound around the tube inside the furnace and is connected
34、to this tube before the closing system. In this case, the steam at the exit of the steam generator is heated to the temperature of the furnace. The extractions of chlorine and fluorine ions are more effective. 5.2.3 Steam generator, consisting of a reservoir for water (4.1) and provisions for heatin
35、g and temperature regulation to adjust the flow rate of the steam. 5.2.4 Combustion boats, of Inconel, platinum, ceramic or quartz. 5.3 Flasks, 50 ml, 100 ml, 200 ml, 250 ml and 1 000 ml, of any material that can be verified not to create Cl and F contamination. 5.4 Balance, capable of reading to th
36、e nearest 0,1 mg. 1) Inconel is an example of a suitable product available commercially. This information is given for the convenience of users of ISO 22875 and does not constitute an endorsement by ISO of this product. ISO 22875:2008(E) 4 ISO 2008 All rights reserved5.5 Ion-exchange chromatography
37、system. 5.5.1 Injection loop, 100 l capacity, able to achieve the reproducibility reported. 5.5.2 Pump. 5.5.3 Separation column, with a separating power sufficient to ensure effective separation of the fluoride and chloride anion peaks all the way to the baseline under the specified operating condit
38、ions. 5.5.4 Neutralization column. 5.5.5 Conductivity measurement sensor. 5.5.6 Sample changer. 5.5.7 PC and software. 5.5.8 Printer. 5.6 Ion analysis measuring equipment. 5.6.1 Millivoltmeter, capable of reading to the nearest 0,1.mV. 5.6.2 Chlorine ion-selective electrode, compatible with the mill
39、ivoltmeter. Test the electrode for satisfactory operation by determining the response curve according to the procedure described in ISO 9892:1992, Annex A, and in accordance with the manufacturers manual. 5.6.3 Fluorine ion-selective electrode. Use an electrode compatible with the millivoltmeter. Te
40、st the electrode for satisfactory operation by determining the response curve according to the procedure described in ISO 9892:1992, Annex A, and in accordance with the manufacturers manual. 5.6.4 Double-junction reference electrode, compatible with the millivoltmeter. 5.7 Mortar. 6 Procedure Make-u
41、p eluant solution (4.10) is added to the flasks for calibration solutions and for the solution used to recover the pyrohydrolysis condensates. 6.1 Calibration 6.1.1 Ion-exchange chromatography calibration Successively perform chromatography analysis on the standard eluant solution (4.9) as a blank s
42、ample, and on the three calibration standards (4.18). For each anion, measure the peak area for each standard solution and subtract the area of the blank solution peak. Calculate the calibration curves for the net peak area (less the blank solution area) versus the concentration of the standard solu
43、tions. 6.1.2 Millivoltmeter calibration Pour about 60 ml of each chloride calibration standard solution (4.12, 4.13 and 4.14) into a separate beaker. Stir each beaker slowly and regularly. Insert the chloride ion-selective electrode (5.6.2). Record the potential value after the equilibrium is reache
44、d, then remove and carefully rinse the electrode in water (4.1). Plot the ISO 22875:2008(E) ISO 2008 All rights reserved 5calibration curve of the measured potentials versus the decimal logarithm of the chloride concentration in the standard solutions. Repeat the same procedure with fluoride calibra
45、tion standard solutions (4.15, 4.16 and 4.17) and the fluorine ion-selective electrode (5.6.3). The temperature of the standard solutions shall be constant for the selective-electrode measurements to avoid the requirement for applying correction factors. 6.2 Sample pyrohydrolysis 6.2.1 Blank test Bl
46、ank tests shall be carried out before and after each series of analyses, as described below. a) Assemble the pyrohydrolysis apparatus (5.2; c.f. example in Figure 1). b) Adjust the temperature of the furnace (5.2.1) to between 900 C and 1 000 C and check the validity of the furnace temperature-regul
47、ating system. c) Adjust the distillate flow rate to 80 ml per 15 min. Purge the device with steam for 30 min. d) Shut off the steam flow by opening stopcock R1 to atmosphere and closing stopcock R2 leading to the tube (5.2.2). Open the tube. Key 1 water 2 combustion boat 3 condenser 4 furnace 5 regu
48、lated steam generator a water.b regulated heating. Figure 1 Schematic diagram of a pyrohydrolysis apparatus ISO 22875:2008(E) 6 ISO 2008 All rights reservede) For a measurement, carry out one of the two following operations: For a chromatographic measurement, add 4 ml of eluant solution (4.9) and ab
49、out 30 ml of water (4.1) to a 250 ml flask (5.3) and insert the flask so that the outlet of the condenser is immersed in the solution. For a measurement with an ion-selective electrode, add 50 ml of buffer solution (4.11) and water (4.1) to a 200 ml flask (5.3) and insert the flask so that the outlet of the condenser is immersed in the solution. f) Place the empty combustion boat (5.2.4) in the tube (5.2.2) and close the tube. g) Restore the steam flow by closing stopc
