1、Designation: C 1220 98 (Reapproved 2004)Standard Test Method forStatic Leaching of Monolithic Waste Forms for Disposal ofRadioactive Waste1This standard is issued under the fixed designation C 1220; the number immediately following the designation indicates the year oforiginal adoption or, in the ca
2、se 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 relative chemical durabilityof simulated and radioactive mono
3、lithic waste forms, such asglasses, ceramics, or cermets, in various test solutions attemperatures 0.5 g/mL, repeat 6.6.1.7-6.6.1.19. If ISE F is still 0.5 g/mL repeat 6.6.1.1-6.6.1.19.6.6.1.20 If ISE F level is 0.5 g/mL, a vessel is accept-able for use.6.6.2 Used VesselsClean used PTFE vessels and
4、supports(that is, vessels and supports that were cleaned according to6.6.1.1-6.6.1.20 and then used for testing) according to 6.6.2.1-6.6.2.8.6.6.2.1 Rinse vessels, lids, and supports with fresh high-purity water. Use at least three vessel volumes of water foreach vessel.6.6.2.2 Soak vessels and sup
5、ports for1hin0.16 M HNO3(1wt % HNO3)at906 10C.6.6.2.3 Rinse again as specified in 6.6.2.1.6.6.2.4 Soak for1hinhigh-purity water at 90 6 10C.6.6.2.5 Fill the vessels approximately 90 % full with freshhigh-purity water with support in place. Close the lids and holdfor at least 16 h at 90 6 2C and then
6、 measure the pH of thewater from each vessel. Take an aliquot of the water from atleast two vessels from each vessel batch and submit for ISE F.6.6.2.6 Repeat 6.6.2.4 and 6.6.2.5 until the pH is in therange of 5.0 to 7.0 and the F is 0.5 g/mL.6.6.2.7 If the pH and fluoride requirements cannot beachi
7、eved by three repetitions of 6.6.2.4 and 6.6.2.5, then repeatthe cleaning procedure starting at 6.6.2.1.6.6.2.8 Dry vessels and lids at 90 6 10C for a minimum of16 h and store inside a clean environment until used.6.6.3 Stainless Steel and Fused Silica VesselsThe proce-dures in 6.6.1 and 6.6.2 are s
8、pecifically for PTFE vessels.When using other inert vessels, such as fused silica or 304Lstainless steel, variations of these procedures are appropriate.6.6.3.1 Clean fused silica vessels using 6.6.2.1-6.6.2.8 ex-cept delete the check for F, which is specific to PTFEcontainers.6.6.3.2 Degrease new 3
9、04L stainless steel vessels and lidswithout gaskets and ultrasonically clean in 95 % ethanol forapproximately 5 min (in order to remove any residual grease oroil left from machining operations) and then clean using thefollowing procedure:6.6.3.3 Rinse three times in high-purity water.6.6.3.4 Submerg
10、e in 0.16 M HNO3(1 wt % HNO3)for1hat 90 6 10C.6.6.3.5 Rinse three times with high-purity water at ambienttemperature.6.6.3.6 Submerge the vessels and lids in fresh high-puritywater for1hat906 10C.6.6.3.7 Rinse with fresh high-purity water at ambient tem-perature.6.6.3.8 Fill the vessel 80 to 90 % fu
11、ll with high-purity water.Close the lid and leave in a 90 6 2C oven for a minimum of16 h.6.6.3.9 Remove the vessels from the oven and cool to roomtemperature, then take a cooled aliquot of the water andmeasure the pH.6.6.3.10 If the pH is not in the range of 5.0 to 7.0, repeat6.6.3.6-6.6.3.9.6.6.3.1
12、1 If the pH is not in the range of 5.0 to 7.0 after 3repetitions of 6.6.3.6-6.6.3.9, repeat the cleaning steps startingat 6.6.2.2.6.6.3.12 Dry the vessels in a 90 6 10C oven for aminimum of 16 h and then cool to room temperature. If theC 1220 98 (2004)4vessels are not used immediately, close the ves
13、sels and store ina clean environment until needed.6.6.4 Cleaning of Used Stainless Steel and Fused SilicaVesselsWhen stainless steel or fused silica vessels are reusedsubsequent to their use with radioactive specimens, residualcontamination may be present. The vessels shall be cleanedbefore reuse us
14、ing 0.16 M HNO3(1 wt % HNO3) andhigh-purity water until the level of the radioactive element ofinterest is below the detectable level using the analyticalmethod employed for concentration measurement of theleachate. Stainless steel vessels are also checked for Si con-tamination before reuse.6.6.4.1
15、Rinse the vessel and lid with high-purity water. Fillthe vessel 80 to 90 % full with 0.16 M HNO3(1 wt % HNO3).Reseal the vessel and place in an oven at 90 6 2C for aminimum of 16 h to acid strip any radionuclides adhering to theinterior of the vessel.6.6.4.2 Check the acid stripped solution for radi
16、oactivity.Repeat 6.6.4.1 until the radioactivity of the acid strip solutionis reduced below the background.6.6.4.3 Remove the gasket and discard. Rinse vessels andlids thoroughly with high-purity water at ambient temperature.Take precautions to prevent contamination of the vessel inte-rior with any
17、radionuclides present on the exterior of the vesselor in the work environment.6.6.4.4 Fill the vessel 80 to 90 % full with fresh high-puritywater. Close the lid using a new, cleaned gasket (see 6.6.5) andplace in oven at 90 6 2C for at least 24 h.6.6.4.5 Remove vessels from oven, then take an aliquo
18、t ofthe water and measure the pH. Take another aliquot andmeasure the radioactivity. For stainless steel vessels, alsomeasure the Si content of the solution.6.6.4.6 If the pH is not in the range of 5.0 to 7.0 or themeasured radioactivity is not at the background level, or Si isdetected for stainless
19、 steel vessels, repeat 6.6.4.3-6.6.4.5.6.6.4.7 If three repetitions of 6.6.4.3-6.6.4.5 do not result ina pH of 5.0 to 7.0, low radioactivity, and Si 1 ppm forstainless steel vessels, then repeat the cleaning starting at6.6.4.1.6.6.4.8 Dry vessels, lids, and gaskets at 90 6 2C for aminimum of 16 h an
20、d store in a clean environment untilneeded.6.6.5 Cleaning of New PTFE Gaskets for Stainless SteelVesselsClean new PTFE gaskets for stainless steel vesselsusing the following method:6.6.5.1 Handle the gaskets only with clean tongs.6.6.5.2 Clean each gasket ultrasonically in 95 % ethanol forapproximat
21、ely 10 min.6.6.5.3 Clean each gasket under flowing high-purity waterat ambient temperature for approximately 3 min.6.6.5.4 Bake each gasket in an oven at 200 6 10C for aminimum of 4 h.6.6.5.5 Immerse each cooled gasket in fresh high-puritywater in a boiling water bath for a minimum of 2 h.6.6.5.6 Dr
22、y gaskets at 90 6 10C for a minimum of 16 hand store in a clean environment until needed.6.7 OvenThe test oven must be capable of controlling thetemperature of the test vessels to within 1C over the range of40 to 100C. Determine the zone within the loaded chamberthat is constant within 1C of the tar
23、get temperature using atleast ten points of temperature measurement. A temperaturerecorder or other monitoring device must be provided to ensurethat the desired temperature has been maintained for theduration of the test. When radioactive specimens are used,ensure that self-heating does not prevent
24、the maintenance ofthe desired leaching temperature (see Note 1). Brief fluctua-tions from the desired temperature are allowable when speci-mens are placed in or removed from the test oven, but thecumulative time of these fluctuations outside 1C of the targettemperature must not exceed 5 % of the tes
25、t period and nofluctuation may be more than 5C above the target temperature.6.8 BalancesBalances shall provide the following accu-racies, depending on the materials being weighed:Leachant + vessels within 0.25 % of the leachantmassChemical reagents within 1 % of the reagent massSpecimens within 0.5
26、mgTABLE 1 Required Calibration ScheduleMeasurement Device Frequency Check and MethodsTemperature thermocouple or thermometer 6 monthsNIST standard or ice/boiling waterelectronics or temperature probe (without sensor) 6 monthsagainst a calibrated millivolt sourceLength micrometer 6 monthsstandard foi
27、ls, gage blocksMass balance 3 monthsNIST standard massesChemical concentration analytical method 3 monthsNIST standards, where possible, 2 times daily (routine),secondary standardspH pH meter each day of use with commercial buffer solutions, and atintervals of 30 to 60 min during measurements. See T
28、estMethods D 1293 and 6.11 for pH measurement guidanceVolume volumetric flasks use certified flasks3 months by measuring the mass of pure water containedpipettes 3 months by measuring the mass of pure water containedActivity counting techniques twice a day, before and after counting NIST or NIST-tra
29、ceablestandard isotope source of interestC 1220 98 (2004)56.9 Volume MeasurementMeasure leachant volumesgravimetrically or with pipettes, burettes, or flasks calibrated asdescribed in Table 1 (see also 6.10) and accurate to within 1 %or better.6.10 Solution AnalysisMeasure solute concentrations us-i
30、ng equipment standardized with standards traceable to NIST,preferably, or other recognized organizations, such as EPA orUSGS. Determine and report precision and bias. Althoughanalytical results should normally be accurate within 10 % ofthe reference solution when checked by individual measure-ments
31、on reference solutions, this may not be possible whenconcentrations in the solution approach detection limits. Thedetection limits for each analysis must accompany the reportedresult. Various analytical techniques can be used to determinethe solute concentrations in leachates, including inductivelyc
32、oupled plasma spectroscopy (see Test Methods C 1109 orEPA SW846a, or both), direct current plasma spectroscopy,atomic absorption emission spectroscopy, and neutron activa-tion. Selection of a specific technique depends on specific testobjectives and the particular solutes of interest. For radioactiv
33、eelements such as actinides and fission products, where lowamounts may be of interest, radiochemistry/radiation countingmay be needed or desirable. Use of blanks and simulatedleachates, as discussed in Section 10, help ensure that high-quality data are obtained.6.11 pH MeasurementMeasure the pH to a
34、n accuracy of0.1 unit using a calibrated meter. Use Test Methods D 1293,Method A and commercial buffers to make this measurement.When measuring the pH of deaerated solutions, make themeasurement under an argon atmosphere.6.12 pH Measurement in Brines:6.12.1 Determination of pH, defined as the negati
35、ve loga-rithm of hydrogen ion activity, in concentrated brines usingstandard glass electrodes is complicated by two principalfactors: (1) a significant liquid junction potential and (2)significant differences between hydrogen ion concentrationsand activities. The result is usually a measured pH valu
36、e that issignificantly smaller than the actual value.6.12.2 A potential at the junction between the referenceelectrode filling solution and the sample solution (“liquidjunction potential”) is present any time these two solutions aredifferent. The potential arises from the interdiffusion of ions inth
37、e two solutions. Since these ions diffuse at different rates, theelectrical charge will be carried unequally across the junction.This results in a potential whose magnitude and stabilitydepends on the composition of the solutions as well as the typeof junction. Glass pH electrodes are usually standa
38、rdizedagainst buffers to establish the pH scale. These buffer solutions,however, are of much lower ionic strength than concentratedbrines, so that significantly different liquid junction potentialsare present in the two cases. The usual result in a saturatedbrine is a measured pH value that is one o
39、r more pH unitssmaller than the actual value.6.12.3 In addition, changes in ion activity coefficients as afunction of ionic strength can be important in pH measure-ments. (Activity is equal to the product of concentration andthe activity coefficient.) Activity coefficients are usually unityin dilute
40、 solutions. However, in solutions of high ionicstrength, average cation-anion activity coefficients can bemuch larger than unity (for example, greater than 10 for HCl insaturated magnesium chloride solutions). Because glass elec-trodes respond to ion activities, not to concentration, there canbe a l
41、arge effect on the measured pH value. The situation iscomplicated by a lack of activity coefficient data in concen-trated brines and a similar lack of theoretical models applicableto such solutions.6.12.4 Considerable caution must be exercised, therefore,when attempting to interpret brine pH measure
42、ments. Liquidjunction and ion activity coefficient effects will result inmeasured pH values being shifted significantly from the truepH (based on H+ ion activities). However, for a given brinesystem, these contributions should be constant for a largeportion of the pH scale, such that trends in the p
43、H will beunaffected. If major changes in brine composition occur duringa given experiment, even trends in measured pH may besuspect. In this test method, the reference brine is a dilutedbrine derived from analysis of Brine A for the Salado Regionin New Mexico.5Other simulated, site-specific referenc
44、ebrines may be used depending on the particular application ofthe test. The bulk composition of the brine solution is not likelyto change significantly in leach tests, and the measurement ofpH to indicate trends of the actual pH during testing is expectedto be valid. For distilled water and the sili
45、cate water, themeasurement of pH is relatively straightforward.6.13 Calibration and StandardsCalibrate all instrumentsused in these tests initially, and periodically, to minimizepossible errors due to drift. Table 1 shows the methods and theminimum frequency of calibration for the various devices us
46、ed.Use standardization procedures that are published by recog-nized authorities such as NIST or ASTM.7. Leachant Preparation and Storage7.1 General Chemicals and ProceduresUse chemicals ofreagent grade or better that conform to the specifications of theCommittee on Analytical Reagents of the America
47、n ChemicalSociety, where such specifications are available.67.1.1 It is recommended that each chemical be analyzed todetermine if impurities, once the leachant is prepared, willexceed detection limits of the leachate analysis system to beused. If impurities will cause detection limits to be exceeded
48、,obtain a different batch of the chemical or use an ultrapurechemical. Good laboratory practice should be used at all timesto minimize contamination of the leachant.7.2 WaterThe water referred to in this procedure isair-saturated (except when deaerated solutions are required),reagent water Type I or
49、 II conforming to Specification D 1193,which has a total impurity level, including organics, of lessthan 0.1 mg/L.5Molecke, M. A., “A Comparison of Brines Relevant to Nuclear WasteExperimentation,” Sandia Report SAND83-0516, Sandia National Laboratories,1983.6Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, 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 Pharm
