ASTM C1220-17 Standard Test Method for Static Leaching of Monolithic Waste Forms for Disposal of Radioactive Waste.pdf

1、Designation: C1220 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 revision, the

2、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 chemicaldurability of a simulated or radioactive monolithic waste f

3、orm,such as a glass, ceramic, cement (grout), or cermet, in a testsolution at temperatures 0.5 g/mL, repeat steps6.5.8 6.5.19.6.5.21 If the Fis still 0.5 g/mL after performing steps6.5.8 6.5.19 twice, repeat steps 6.5.1 6.5.19.6.5.22 If the Fconcentration is 1ppm is detected for stainless steel vess

4、els, repeat steps 6.10.2 6.10.8.6.10.10 If three repetitions of steps 6.10.2 6.10.8 do notresult in a pH within the range of 5.0 to 7.0, radioactivity belowdetection, and Si 1 ppm for stainless steel vessels, then repeatthe cleaning starting at step 6.10.1.6.10.11 Dry vessels, lids, and gaskets at 9

5、0 6 2C for aminimum of 16 h and store in a clean environment untilneeded.6.11 Cleaning Solution BottlesSolution bottles that willbe used to contain analytical samples should be cleaned beforeuse. Clean solution bottles using steps 6.11.1 6.11.3.6.11.1 Rinse bottles three times with a dilute nitric a

6、cidsolution (2 wt %). For each rinse, fill bottle to about 10 %bottle volume, place cap on bottle, and shake to rinse allsurfaces. Dispose of solution.6.11.2 Rinse bottles three times with reagent grade (demin-eralized) water. For each rinse, fill bottle to about 25 % bottlevolume, place cap on bott

7、le, and shake to rinse all surfaces.Dispose of rinse water.6.11.3 Dry bottle and cap in oven, then place cap on bottleand store until use.6.12 Mass MeasurementMaterial masses shall be deter-mined with balances that provide the following accuracies,depending on the materials being weighed:6.13 Volume

8、 MeasurementMeasure leachant volumes gra-vimetrically or with pipettes, burettes, or flasks calibrated asdescribed in Table 1.6.14 Solution AnalysisMeasure solute concentrations us-ing equipment standardized with standards traceable to NIST,preferably, or other recognized organizations, such as EPA

9、orUSGS.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 referencesolutions, this may not be possible when concentrations in thesolution are near detection limits. The detection li

10、mits for eachanalysis must accompany the reported result.6.14.2 Various analytical techniques can be used to deter-mine the solute concentrations in leachates, including induc-tively coupled plasma spectroscopy (see Practice C1109 orEPA SW-846A, or both), direct current plasma spectroscopy,atomic ab

11、sorption emission spectroscopy, and neutron activa-tion. Selection of a specific technique depends on specific testobjectives and the particular solutes of interest. For radioactiveelements such as actinides and fission products, where smallamounts may be of interest, radiochemistry/radiation counti

12、ngmay be needed or desirable.6.14.3 Analyzing blanks and simulated leachates with testsolutions helps ensure that high-quality data are obtained.6.15 pH MeasurementMeasure the pH to an accuracy of0.1 unit using an electrode and meter calibrated with commer-cial buffers or buffers obtained from NIST.

13、 Follow Test MethodD1293, Method A to make this measurement.6.15.1 When measuring the pH of a deaerated solution,conduct the measurement under an argon atmosphere.TABLE 1 Required Accuracy for Mass DeterminationsLeachant and vessels within 0.25 % of the leachant massChemical reagents usedto prepare

14、leachantwithin 1 % of the reagent massTest specimens within 0.5 mgC1220 17645 6.15.2 When measuring the pH of a brine solution, themeasured value will be affected by a significant liquid junctionpotential that is sensitive to the ionic strength and the activitycoefficient of hydrogen that will diffe

15、rent significantly fromunity. These effects lead to large uncertainties in the measuredvalues. They are discussed in more detail in Appendix X1.6.16 Calibration and StandardsCalibrate all instrumentsused in these tests prior to use and check periodically tominimize possible errors due to drift. Tabl

16、e 2 shows themethods and the minimum frequency of calibration for thevarious devices used. Use standardized procedures that arepublished by recognized authorities such as NIST or ASTM.7. Leachant Preparation and Storage7.1 General Chemicals and ProceduresUse chemicals ofreagent grade or better that

17、conform to the specifications of theCommittee on Analytical Reagents of the American ChemicalSociety, where such specifications are available.5It is recom-mended that the assays of each chemical be assessed todetermine if impurities, once the leachant is prepared, willexceed detection limits of the

18、analysis system to be used. Ifimpurities will cause detection limits to be exceeded, obtain adifferent batch of the chemical or use an ultrapure chemical.Good laboratory practice should be used at all times tominimize contamination of the leachant.7.1.1 Although any leachant can be used in tests, re

19、cipes fora reference brine leachant and a reference silicate leachant areprovided to facilitate comparisons of test results from differentlaboratories. The reference brine and silicate leachant compo-sitions are not intended to represent any particular groundwaters.7.1.2 Blank tests must be conducte

20、d with all leachants tomeasure the stability of the leachant under the test conditionsand interactions with the vessel and support.7.1.3 The density of all leachants should be measured topermit the addition of leachant to the individual leach tests byweight rather than by volume.7.2 Demineralized Wa

21、terThe water referred to in thisprocedure is air-saturated reagent water Type I or II conform-ing to Specification D1193, with a total impurity level, includ-ing organics, of less than 0.1 mg/L.7.2.1 Radiolysis of gases dissolved in water can become animportant factor in tests with radioactive mater

22、ials. Therefore,deaerated leachants should be used in tests with radioactivespecimens.7.2.2 To deaerate demineralized water for use in leachantpreparation, boil high-purity water for 15 min while purgingwith argon. Immediately place the hot water under an argonatmosphere to cool. Prepare the leachan

23、ts as described belowusing the cooled, deaerated water in an argon atmosphere.7.2.3 The density of pure air-free water at 23C is 0.9976g/cm3.7.3 Preparation of Reference Brine LeachantPrepare thereference brine by dissolving 48.2 g KCl, 90.0 g NaCl, and116.0 g MgCl2(247.9 g MgCl26H2O) in enough demi

24、neral-ized water to make approximately 900 mL of solution. Adjustthe pH to fall within the range of 6.4 to 6.6 by dropwiseaddition of 0.01 M NaOH or 0.01 M HCl. Then add water tomake 1.00 L of solution. Analyze the leachant to verify thecomposition and to determine impurity concentrations. Discardth

25、e leachant if the concentration of any constituent is in errorby more than 10 % from the recipe concentration, which is35.4 g Na+/L, 54.9 mg K+/L, 29.6 mg Mg2+/L, and164 mg Cl/L (neglecting the Na and Cl added as NaOH andHCI).7.3.1 The density of the brine leachant should be measuredto permit the ad

26、dition of aliquots of brine leachant to theindividual leach tests by weight rather than by volume.5Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar

27、Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.TABLE 2 Required Calibration ScheduleMeasurement Device Frequency Check and MethodsTemperature thermocouple or thermome

28、ter 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 monthsNIST standard massesChemical concentration analytical method 3 monthsNIST sta

29、ndards, 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 guidanceVolume volumetric flasks use certified flasks or before use by measuring the ma

30、ss 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 radionuclide of interestC1220 17745 7.3.2 CautionWhen using brine in radiation fields, hy-

31、drogen gas will be generated and may pressurize the testvessel. Take the appropriate precautions when making suchstudies. Use appropriate pressure-rated test vessels or vesselswith gas vents, or both.Also, since chloride brines can becomevery corrosive under high radiation fields, use caution whense

32、lecting the test vessel material.7.4 Preparation of Reference Silicate Water LeachantPrepare the silicate water leachant by dissolving 0.179 gNaHCO3and 0.096 g SiO22H2O in enough demineralizedwater to make about 900 mL of solution. Adjust the pH towithin 0.1 unit of 7.5 with 0.01 M HCl.Add water to

33、make 1.00L of solution.7.4.1 Analyze an aliquant of the leachant to verify thecomposition (27.1 mg Si/L) and to determine impurity concen-trations. Discard the leachant if the concentration of anyconstituent is in error by more than 10 %.7.4.2 The density of the silicate water leachant should bemeas

34、ured to permit the addition of aliquots of leachant to theindividual leach tests by weight rather than by volume.7.5 Repository Water LeachantsWhen actual ground wa-ters or leachants that are representative of specific repositorywaters are used, the rigor with which the data characterizingthe water

35、are obtained must be the same as for the threereference leachants. Record the type of repository water used,where and when it was obtained or how it was prepared if madeup in the laboratory, results of its chemical compositionanalysis, the presence of colloidal material, etc. of any precipi-tates th

36、at may have been formed in the blanks during the test.7.5.1 Analyze an aliquant of the leachant to measure thecomposition.7.5.2 The density of the ground water should be measured topermit the addition of aliquots to the individual leach tests byweight rather than by volume.7.6 Other LeachantsOther l

37、eachant solutions are usefulwhen using the test to study the waste form degradationmechanism and measuring model parameters. For example, pHbuffer solutions can be used to measure the effect of pH on thetest response and leachants with added components can be usedto measure common ion (solution feed

38、-back) effects.7.7 Leachant StorageUse polyethylene or polypropylenebottles with tight-fitting lids to store the leachants. Cleanbottles before use following the cleaning steps given in 6.11.7.7.1 Use the leachant immediately or store in a sealedvessel until beginning the test. If the leachant is no

39、t used withinone month after it is prepared, report the storage time andverify the composition by analysis before use in tests. Naturalgroundwaters should be stored in a dark location to prevent thegrowth of algae.7.7.2 Store deaerated solutions in a tightly sealed containerwith an argon atmosphere

40、above the liquid level and for nolonger than one week.8. Test Specimen Preparation8.1 Test specimens may be either fabricated individually orcut from larger samples of the waste-form material.8.1.1 When cutting a specimen from a larger sample, avoidthe use of wax or adhesives to hold the sample bein

41、g cut. Ifadhesive materials must be used, none of the surfaces of theresulting test specimen shall be surfaces to which the adhesivewas applied.8.1.2 Sawing and cutting test specimens for tests to beconducted in deaerated solutions need not be done in an argonatmosphere. However, a final specimen cl

42、eaning step must becarried out under an argon atmosphere using deaerated deion-ized water.8.1.3 The surfaces of individually fabricated test specimensmay not be representative of the bulk material due to formationof a surface skin, and the responses of such specimens may notbe representative of the

43、bulk material. If separate specimensare cast for each test, the user should determine the effect of theas-cast surface by comparing results of tests conducted with anas-cast specimen and a cut specimen without the outer layerhas been removed.8.2 Characterization of Source MaterialThe source mate-ria

44、l is the sample from which test specimens are extracted. Ifpossible document the fabrication method and fabricationconditions for the source material and provide information onhow test specimens were selected. The researcher must includeinformation on the chemical and radiochemical (if applicable)co

45、mposition and compositional variations of the source mate-rial. This information should be obtained from bulk chemicaland radiochemical analyses. Include information on chemical-composition variations within the fabricated material, as wellas within and between specimens. For certain radioactivesamp

46、les, autoradiography may be necessary to determine thedistribution of alpha-emitting isotopes. The researcher mayalso wish to characterize the source material with opticalmicroscopy, XRD, SEM-EDX, TEM, or other analytical meth-ods to document microcracking, phase identification, relativeconcentratio

47、ns of phases, and homogeneity between test speci-mens.8.2.1 For specimens in which an as-fabricated surface is tobe leached, analysis of a surface cross-section by SEM-EDX orother applicable surface spectroscopy techniques is also re-quired to determine whether the surface composition differsfrom th

48、e bulk composition. If differences do exist, the possibleeffects on the test results should be discussed with the testresults.8.2.2 When the waste form source material is a heteroge-neous or multiphase material, it may not be possible to producetest specimens exposing equal amounts of all phases to

49、theleachants in a test series. In this case, the test operator mustdocument the differences between the test specimens that areused to ensure that the test specimens contain a representativedistribution of the different phases. This should be documentedwith optical microscopy, SEM-EDX, or other applicable tech-niques. Individual particles of component phases may be largeenough relative to the dimensions of the test specimen toestimate the exposed area.8.3 Test SpecimensThe test specimen is preferably pre-pared as a regularly shaped monoli