1、Designation: C1220 10C1220 17Standard Test Method forStatic Leaching of Monolithic Waste Forms for Disposal ofRadioactive Waste1This standard is issued under the fixed designation C1220; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisi
2、on, 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 provides a measure of the chemical durability of a simulated or radioactive monolithi
3、c waste form, suchas a glass, ceramic, cement (grout), or cermet, in a test solution at temperatures 0.5 g/mL, repeat steps 6.5.8 6.5.19.6.5.21 If the F is still 0.5 g/mL after performing steps 6.5.8 6.5.19 twice, repeat steps 6.5.1 6.5.19.6.5.22 If the F concentration is 1 ppm isdetected for stainl
4、ess steel vessels, repeat steps 6.10.2 6.10.8.6.10.10 If three repetitions of steps 6.10.2 6.10.8 do not result in a pH within the range of 5.0 to 7.0, radioactivity belowdetection, and Si 1 ppm for stainless steel vessels, then repeat the cleaning starting at step 6.10.1.6.10.11 Dry vessels, lids,
5、and gaskets at 90 6 2C for a minimum of 16 h and store in a clean environment until needed.6.11 Cleaning Solution BottlesSolution bottles that will be used to contain analytical samples should be cleaned before use.Clean solution bottles using steps 6.11.1 6.11.3.6.11.1 Rinse bottles three times wit
6、h a dilute nitric acid solution (2 wt %). For each rinse, fill bottle to about 10 % bottlevolume, place cap on bottle, and shake to rinse all surfaces. Dispose of solution.6.11.2 Rinse bottles three times with reagent grade (demineralized) water. For each rinse, fill bottle to about 25 % bottle volu
7、me,place cap on bottle, and shake to rinse all surfaces. Dispose of rinse water.6.11.3 Dry bottle and cap in oven, then place cap on bottle and store until use.6.12 Mass MeasurementMaterial masses shall be determined with balances that provide the following accuracies, dependingon the materials bein
8、g weighed:6.13 Volume MeasurementMeasure leachant volumes gravimetrically or with pipettes, burettes, or flasks calibrated asdescribed in Table 1.6.14 Solution AnalysisMeasure solute concentrations using equipment standardized with standards traceable to NIST,preferably, or other recognized organiza
9、tions, such as EPA or USGS.6.14.1 Determine and report precision and bias for analyses. Although analytical results should normally be accurate within10 % when checked by individual measurements on reference solutions, this may not be possible when concentrations in thesolution are near detection li
10、mits. The detection limits for each analysis must accompany the reported result.6.14.2 Various analytical techniques can be used to determine the solute concentrations in leachates, including inductivelycoupled plasma spectroscopy (see Practice C1109 or EPA SW-846A, or both), direct current plasma s
11、pectroscopy, atomicabsorption emission spectroscopy, and neutron activation. Selection of a specific technique depends on specific test objectives andTABLE 1 Required Accuracy for Mass DeterminationsLeachant and vessels within 0.25 % of the leachant massChemical reagents usedto prepare leachantwithi
12、n 1 % of the reagent massTest specimens within 0.5 mgC1220 177the particular solutes of interest. For radioactive elements such as actinides and fission products, where small amounts may be ofinterest, radiochemistry/radiation counting may be needed or desirable.6.14.3 Analyzing blanks and simulated
13、 leachates with test solutions helps ensure that high-quality data are obtained.6.15 pH MeasurementMeasure the pH to an accuracy of 0.1 unit using an electrode and meter calibrated with commercialbuffers or buffers obtained from NIST. Follow Test Method D1293, Method A to make this measurement.6.15.
14、1 When measuring the pH of a deaerated solution, conduct the measurement under an argon atmosphere.6.15.2 When measuring the pH of a brine solution, the measured value will be affected by a significant liquid junction potentialthat is sensitive to the ionic strength and the activity coefficient of h
15、ydrogen that will different significantly from unity. Theseeffects lead to large uncertainties in the measured values. They are discussed in more detail in Appendix X1.6.16 Calibration and StandardsCalibrate all instruments used in these tests prior to use and check periodically to minimizepossible
16、errors due to drift. Table 2 shows the methods and the minimum frequency of calibration for the various devices used.Use standardized procedures that are published by recognized authorities such as NIST or ASTM.7. Leachant Preparation and Storage7.1 General Chemicals and ProceduresUse chemicals of r
17、eagent grade or better that conform to the specifications of theCommittee onAnalytical Reagents of theAmerican Chemical Society, where such specifications are available.5 It is recommendedthat the assays of each chemical be assessed to determine if impurities, once the leachant is prepared, will exc
18、eed detection limitsof the analysis system to be used. If impurities will cause detection limits to be exceeded, obtain a different batch of the chemicalor use an ultrapure chemical. Good laboratory practice should be used at all times to minimize contamination of the leachant.7.1.1 Although any lea
19、chant can be used in tests, recipes for a reference brine leachant and a reference silicate leachant areprovided to facilitate comparisons of test results from different laboratories. The reference brine and silicate leachant compositionsare not intended to represent any particular ground waters.7.1
20、.2 Blank tests must be conducted with all leachants to measure the stability of the leachant under the test conditions andinteractions with the vessel and support.7.1.3 The density of all leachants should be measured to permit the addition of leachant to the individual leach tests by weightrather th
21、an by volume.7.2 Demineralized WaterThe water referred to in this procedure is air-saturated reagent water Type I or II conforming toSpecification D1193, with a total impurity level, including organics, of less than 0.1 mg/L.7.2.1 Radiolysis of gases dissolved in water can become an important factor
22、 in tests with radioactive materials. Therefore,deaerated leachants should be used in tests with radioactive specimens.7.2.2 To deaerate demineralized water for use in leachant preparation, boil high-purity water for 15 min while purging withargon. Immediately place the hot water under an argon atmo
23、sphere to cool. Prepare the leachants as described below using thecooled, deaerated water in an argon atmosphere.7.2.3 The density of pure air-free water at 23C is 0.9976 g/cm3.5 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions o
24、n the testing of reagents not listed bythe American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.TABLE 2 Required Calibration Schedul
25、eMeasurement Device Frequency Check and MethodsTemperature thermocouple or thermometer 6 monthsNIST standard or ice/boiling waterVoltage electronics or temperature probe (without sensor) 6 monthsagainst a calibrated millivolt sourceLength micrometer 6 monthsstandard foils, gage blocksMass balance 3
26、monthsNIST standard massesChemical concentration analytical method 3 monthsNIST standards, where possible, 2 times daily (routine),secondary standardsbefore use with commercial or NIST buffer solutions, and atintervals of 60 min during measurementspH pH meter See Test Methods D1293 and 6.11 for guid
27、anceVolume volumetric flasks use certified flasks or before use by measuring the mass ofpure water containedpipettes before use by measuring the mass of pure water transferredActivity counting techniques twice a day, before and after counting NIST or NIST-traceablestandard isotope source for radionu
28、clide of interestC1220 1787.3 Preparation of Reference Brine LeachantPrepare the reference brine by dissolving 48.2 g KCl, 90.0 g NaCl, and 116.0g MgCl2 (247.9 g MgCl26H2O) in enough demineralized water to make approximately 900 mL of solution. Adjust the pH to fallwithin the range of 6.4 to 6.6 by
29、dropwise addition of 0.01 M NaOH or 0.01 M HCl. Then add water to make 1.00 L of solution.Analyze the leachant to verify the composition and to determine impurity concentrations. Discard the leachant if the concentrationof any constituent is in error by more than 10 % from the recipe concentration,
30、which is 35.4 g Na+/L, 54.9 mg K+/L, 29.6 mgMg2+/L, and164 mg Cl/L (neglecting the Na and Cl added as NaOH and HCI).7.3.1 The density of the brine leachant should be measured to permit the addition of aliquantsaliquots of brine leachant to theindividual leach tests by weight rather than by volume.7.
31、3.2 CautionWhen using brine in radiation fields, hydrogen gas will be generated and may pressurize the test vessel. Takethe appropriate precautions when making such studies. Use appropriate pressure-rated test vessels or vessels with gas vents, orboth. Also, since chloride brines can become very cor
32、rosive under high radiation fields, use caution when selecting the test vesselmaterial.7.4 Preparation of Reference Silicate Water LeachantPrepare the silicate water leachant by dissolving 0.179 g NaHCO3 and0.096 g SiO22H2O in enough demineralized water to make about 900 mL of solution.Adjust the pH
33、 to within 0.1 unit of 7.5 with0.01 M HCl. Add water to make 1.00 L of solution.7.4.1 Analyze an aliquant of the leachant to verify the composition (27.1 mg Si/L) and to determine impurity concentrations.Discard the leachant if the concentration of any constituent is in error by more than 10 %.7.4.2
34、 The density of the silicate water leachant should be measured to permit the addition of aliquantsaliquots of leachant tothe individual leach tests by weight rather than by volume.7.5 Repository Water LeachantsWhen actual ground waters or leachants that are representative of specific repository wate
35、rsare used, the rigor with which the data characterizing the water are obtained must be the same as for the three reference leachants.Record the type of repository water used, where and when it was obtained or how it was prepared if made up in the laboratory,results of its chemical composition analy
36、sis, the presence of colloidal material, etc. of any precipitates that may have been formedin the blanks during the test.7.5.1 Analyze an aliquant of the leachant to measure the composition.7.5.2 The density of the ground water should be measured to permit the addition of aliquantsaliquots to the in
37、dividual leach testsby weight rather than by volume.7.6 Other LeachantsOther leachant solutions are useful when using the test to study the waste form degradation mechanismand measuring model parameters. For example, pH buffer solutions can be used to measure the effect of pH on the test responseand
38、 leachants with added components can be used to measure common ion (solution feed-back) effects.7.7 Leachant StorageUse polyethylene or polypropylene bottles with tight-fitting lids to store the leachants. Clean bottlesbefore use following the cleaning steps given in 6.11.7.7.1 Use the leachant imme
39、diately or store in a sealed vessel until beginning the test. If the leachant is not used within onemonth after it is prepared, report the storage time and verify the composition by analysis before use in tests. Natural groundwatersshould be stored in a dark location to prevent the growth of algae.7
40、.7.2 Store deaerated solutions in a tightly sealed container with an argon atmosphere above the liquid level and for no longerthan one week.8. Test Specimen Preparation8.1 Test specimens may be either fabricated individually or cut from larger samples of the waste-form material.8.1.1 When cutting a
41、specimen from a larger sample, avoid the use of wax or adhesives to hold the sample being cut. If adhesivematerials must be used, none of the surfaces of the resulting test specimen shall be surfaces to which the adhesive was applied.8.1.2 Sawing and cutting test specimens for tests to be conducted
42、in deaerated solutions need not be done in an argonatmosphere. However, a final specimen cleaning step must be carried out under an argon atmosphere using deaerated deionizedwater.8.1.3 The surfaces of individually fabricated test specimens may not be representative of the bulk material due to forma
43、tion ofa surface skin, and the responses of such specimens may not be representative of the bulk material. If separate specimens are castfor each test, the user should determine the effect of the as-cast surface by comparing results of tests conducted with an as-castspecimen and a cut specimen witho
44、ut the outer layer has been removed.8.2 Characterization of Source MaterialThe source material is the sample from which test specimens are extracted. If possibledocument the fabrication method and fabrication conditions for the source material and provide information on how test specimenswere select
45、ed. The researcher must include information on the chemical and radiochemical (if applicable) composition andcompositional variations of the source material. This information should be obtained from bulk chemical and radiochemicalanalyses. Include information on chemical-composition variations withi
46、n the fabricated material, as well as within and betweenspecimens. For certain radioactive samples, autoradiography may be necessary to determine the distribution of alpha-emittingC1220 179isotopes. The researcher may also wish to characterize the source material with optical microscopy, XRD, SEM-ED
47、X, TEM, orother analytical methods to document microcracking, phase identification, relative concentrations of phases, and homogeneitybetween test specimens.8.2.1 For specimens in which an as-fabricated surface is to be leached, analysis of a surface cross-section by SEM-EDX or otherapplicable surfa
48、ce spectroscopy techniques is also required to determine whether the surface composition differs from the bulkcomposition. If differences do exist, the possible effects on the test results should be discussed with the test results.8.2.2 When the waste form source material is a heterogeneous or multi
49、phase material, it may not be possible to produce testspecimens exposing equal amounts of all phases to the leachants in a test series. In this case, the test operator must document thedifferences between the test specimens that are used to ensure that the test specimens contain a representative distribution of thedifferent phases. This should be documented with optical microscopy, SEM-EDX, or other applicable techniques. Individualparticles of component phases may be large enough relative to the dimensions of the test specimen to estimate the e
