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Waste Forms Technology and Performance: Final Report (2011)

Chapter: 5 Waste Form Testing

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Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
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5

Waste Form Testing

The third charge of the statement of task for this study (see Box 2.1 in Chapter 2) calls for the identification and description of “state-of-the-art tests and models of waste forms used to predict their performance for time periods appropriate to their disposal system.” This chapter describes waste form testing and the use of test results to inform the development of models for evaluating the long-term (103-106 year) performance of waste forms and their associated disposal systems.1 The application of such models to waste forms and disposal environments is discussed in Chapter 7.

In the context of this report, a test is a laboratory procedure for measuring short-term (days to months) release rates of radioactive and chemical constituents from a waste form material and the formation of reaction products. It typically involves the leaching of a monolithic or crushed specimen of a waste form material under carefully controlled conditions. Release rates reflect the durability of a waste form material, that is, its resistance to physical and chemical alteration.

A large number of standard test protocols have been established by the American Society for Testing and Materials (ASTM) and other organizations; some of the principal tests that are used to investigate waste form materials for disposal applications are described in this chapter.

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1 Box 5.1 provides definitions for a number of specialized terms that are used in this chapter.

Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
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BOX 5.1
Key Terms and Concepts

Experiment: The application of tests to a waste form material to gain a better understanding of its degradation behavior and the release of radioactive constituents.

Dissolution: A process (or processes) by which mass transport from a solid waste form to a liquid takes place (see ASTM C1308, ASTM C1220). Dissolution is the result of mechanistic reactions in which chemical bonds are broken and constituents are released from a material and become solvated in a test solution (see ASTM C1662).

Dissolution rate: The rate of mass removal per unit time normalized to surface area of the material.

Durability: The resistance of a waste form material to chemical and physical alteration and the associated release of contained radioactive and hazardous constituents.

Leaching: The loss of radioactive or chemical constituents from a waste form by diffusion or dissolution.

Performance: The ability of a waste form (waste form performance) or a disposal system containing the waste form (disposal system performance) to sequester radioactive and chemical constituents.

Release mechanisms: The process that controls the rate of mass transport out of a specimen during dissolution (see ASTM C1308).

Solubility: The thermodynamically limited saturation state or equilibrium concentration limit of species in solution.

Standard test protocols: A standardized procedure for testing a specific type of material to generate a clearly defined test response. In principle, any test can be applied to any material to generate a response. However, a response will be meaningful only when the test and material are matched appropriately (see Section 5.1).

Waste form qualification: Demonstration that a waste form material will have acceptable performance in a specific disposal facility and can be fabricated with acceptable performance control.

Waste form test protocols: Standard tests developed by organizations such as the American Nuclear Society, American Society of Testing and Materials, International Atomic Energy Agency, and the International Organization for Standardization (see Section 5.3).

5.1 PURPOSE OF WASTE FORM TESTING

Laboratory testing of waste form materials is undertaken for several purposes, including to:

  • Conduct experiments to elucidate the release mechanisms of radioactive and chemical constituents from a waste form material.
Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
×
  • Control waste form production.
  • Ensure that production results in an acceptable waste form material.
  • Provide the information needed to model the performance of waste forms in disposal systems.

These applications are described briefly in the following paragraphs.

Experiments involve the application of tests to waste form materials to gain a better understanding of their degradation behavior and release of constituents. These experiments may or may not be developed as standard protocols, but rather they are designed to address and challenge specific hypotheses about the behavior of waste form materials. Such experiments can also involve modeling and other types of measurements, for example, compositional analyses of alteration products that are formed on the surfaces of waste form materials during release.

Radioactive and chemical constituents can be released from a waste form material by one or more of the following three mechanisms:

  • Reaction affinity-controlled release: Release is controlled by the difference in Gibbs free energy between the thermodynamically stable state and the metastable reactants.
  • Solubility-controlled release: Release is bounded by the use of the maximum saturation of a constituent species from the waste form in the given leachant (solution) environment.
  • Diffusion-controlled release: Release is controlled by the diffusion of a constituent in the waste form material, including diffusion through an encapsulant and/or through surface layers containing reaction products, if present.

In some cases a change in oxidation state of the constituent may occur prior to its release.

Laboratory experiments on natural analogues of waste form materials (e.g., basalt glass as a natural analogue for borosilicate glass) allow one to gain insights into the similarities and differences in release mechanisms. Short-term studies of natural analogues can also be extended to investigate other material properties, for example, for comparing radiation damage in actinide-doped materials with damage in uranium- and thorium-bearing minerals (Weber et al., 1994).

Testing for production control is used to determine how the production of a waste form material affects (or controls) its performance, and also to identify the ranges of processing variables that produce acceptable waste forms. The primary role of production control testing is to verify that the properties of a specific waste form product are consistent with the waste

Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
×

form material deemed to be acceptable for disposal, either by direct measurement or through process control.

Waste form acceptance testing is intended to show that the waste form produced within production control limits will have acceptable performance in a disposal facility. The performance of a waste form in a disposal facility depends on the environmental conditions in that facility (see Chapter 6). Waste form acceptability also depends on the performance requirements for that disposal facility (Ebert, 2008; see Chapter 8).

The acceptability of a waste form material for disposal is determined through predictive modeling studies (Chapter 7). These models use various thermodynamic and kinetic approaches, but most models used in the United States are based on irreversible thermodynamic (or steady state) transition state theory (TST). The information derived from laboratory tests can be used to parameterize these predictive models (e.g., Grambow, 1985; Grambow and Muller, 2001).2 In some cases, it may be necessary to accelerate releases from a waste form material to obtain the necessary information. This can be done by altering the parameters of a laboratory test, for example, surface area (SA), time (t), temperature (T), or a combination such as (SA) × (t). This is a useful approach so long as the alterations do not change the release mechanisms.

The testing of a waste form material in the laboratory can be related to acceptable performance of that material in a disposal facility by the following linking relationships (Ebert 2008; Plodinec and Ramsey, 1994):3

images

These linking relationships provide a logical technical approach for identifying an acceptable range of processing and composition controls based on the range of waste form release rates and level of disposal system performance deemed acceptable by regulators. In other words, these relationships provide a technical basis for identifying an acceptable waste form release rate under particular test conditions because those test conditions can be related to performance.

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2 The tests described in this chapter provide the fundamental information shown at the base of the Performance Assessment Pyramid (see Figure 7.2) that enables such modeling.

3 Other approaches could be used, depending on the process for producing the waste form. For example, one could combine careful control of processing conditions with a frequent sampling procedure to ensure that the proper product has been produced.

4 Dissolution rate control is achieved by modifying the composition and or waste-loading of the waste form.

Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
×

For high-level waste (HLW) glass (i.e., alkali borosilicate glass) this linking relationship was established in a stepwise fashion:

  • Develop an acceptable waste form durability specification based on HLW performance modeling. As discussed in Chapter 8, acceptable fractional release rates for waste forms in a generic geologic repository were determined to be between 10–4 to 10–6 parts per year5 (Crandall, 1983). Because early versions of 10 CFR Part 60.1136 specified fractional release rates of 10–5 parts per year, which was in the middle of the range determined by HLW performance modeling, this rate was adopted as the waste form specification.
  • Select a waste form material that had the potential to meet this specification. As discussed in Chapter 8, borosilicate glass was selected as a waste form material for several reasons, including its potential ability to meet this performance specification.
  • Develop an understanding of borosilicate glass durability mechanisms from a combination of ASTM test protocols (ASTM C1220, ASTM C1285, ASTM C1662), which were then a suite of tests under development by the Materials Characterization Center (MCC) (see Appendix 5.A for a history of test development). These test protocols are described in Appendix 5.C.
  • Develop a glass standard, the Environmental Assessment (EA) glass, which bounded the upper release rate found to be acceptable from HLW performance modeling and 10 CFR Part 60.113.7
  • Generate a substantial database for modeling the maximum radioactive release rate(s), which happens to be for technetium-99, iodine-129, and cesium-135,8 by the release of non-radioactive species such as sodium, lithium, and boron, which release at the same rate (i.e., congruently; see Box 5.2).
  • Develop a standard test for ensuring that every glass produced has a release rate less than that of the EA glass based on sodium, lithium, and boron, which in turn ensures performance control and acceptable performance.
  • Using this standard test, continue to periodically verify that the durability of the production glass meets performance specifications.

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5 That is, the waste form would take 104 to 106 years to completely dissolve.

6 Waste Package Performance Objective; see Chapter 8.

7 This acceptable release rate was based on a bounding calculation for a generic repository. The actual dissolution rate of a waste form material after emplacement in a disposal facility will depend on the specific geochemical and hydrological characteristics of that facility.

8 Technetium-99, iodine-129, and cesium-135 are not solubility limited; consequently, these radionuclides are released at maximum forward (initial) rates of dissolution.

Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
×

BOX 5.2
Congruent vs. Incongruent Dissolution

The term congruency describes the dissolution behavior of atomic species (including radioactive species) in a waste form material as that material reacts with a solution.

If species dissolve in proportion to their presence in a waste form material (i.e., in stoichiometric proportions), then dissolution is said to be congruent. In such cases, the rate of release of species from the waste form is proportional to both the dissolution rate of the waste form and the relative abundance of those species in the waste form. For materials that exhibit this behavior, for example borosilicate glass in a high pH under-saturated solution, the dissolution behavior of non-radioactive species such as sodium, lithium, and boron can be conveniently used to monitor the releases of radionuclides such as technetium-99, iodine-129, and cesium-135. Decades of research have provided the basis for this relationship to be used for HLW borosilicate glass (Bates et al., 1983; Bazan et al., 1987; Bibler and Bates, 1990; Bibler and Jurgensen, 1988; Bradley et al., 1979; Ebert et al., 1996; Fillet et al., 1985; McGrail, 1986; Ojovan et al., 2006; Vernaz and Godon, 1992).

If some species in the waste form material dissolve preferentially to others, then dissolution is said to be incongruent. Incongruent dissolution is often diffusion-controlled and can be surface reaction affinity-limited under conditions of near saturation or mass transport-controlled. Preferential phase dissolution, ion-exchange reactions, grain-boundary dissolution, and dissolution-reaction product formation (surface crystallization and recrystallization) are among the more likely mechanisms of incongruent dissolution. Precipitation of a secondary phase or phases can also lead to incongruent dissolution.

Apparent incongruent dissolution can occur in complex monophase or polyphase crystalline ceramic waste forms. For example, a multiphase ceramic waste form may contain sodium in more than one phase, whereas species such as technetium-99 are only sequestered in one of the sodium-containing phases. In this case, each phase undergoes congruent dissolution, but technetium-99 and sodium will not be released into solution at the same rate.

This approach was the basis for qualifying HLW glass from West Valley and the Savannah River Site in the Yucca Mountain Total System Performance Assessment–License Application (TSPA-LA) (Ebert, 2000). It was also the approach used in the Hanford performance evaluation for low-activity waste (LAW) glass intended for shallow-land burial (Mann et al., 2001) and to qualify glass-bonded sodalite for disposal in a deep geological repository (Ebert, 2005). A similar approach was also taken by Ebert (2005) to qualify a metallic waste form.

The HLW EA glass (Jantzen et al., 1993, 1994) standard does not necessarily apply to other types of glasses. For example, another glass

Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
×

standard, the LAW Reference Material (LRM) glass standard,9 was developed for Hanford’s Immobilized LAW (ILAW) glass. The LRM contained the glass components anticipated to be present in the Hanford low-activity waste streams as well as those that may be added to facilitate vitrification or improve the durability of the ILAW waste products (Ebert and Wolf, 1999). Extensive testing was again used to demonstrate that the most soluble radionuclides (i.e., those that are not solubility limited) were released congruently (Box 5.2) to sodium, lithium, and boron in the glass to qualify it for near-surface disposal.

5.2 TEST SELECTION

A suite of standard laboratory tests have been developed (Appendix 5.C) to measure the release behavior of waste form materials. The selection of a particular test for a particular waste form material depends on that material’s release mechanism (Table 5.1). Standard tests established for use on materials that release by one mechanism, such as glass that preferentially releases its constituents by reaction affinity-control under non-saturated conditions, cannot necessarily be applied to materials that release by a different mechanism, such as cement that releases constituents by diffusion (e.g., Ojovan and Lee, 2005). Similarly, one cannot apply standard tests for borosilicate glasses to non-borosilicate glasses, because it is not known whether constituents in the latter material release congruently (Box 5.2) by the same mechanism(s). In these cases, new standard tests need to be developed, or existing standard tests need to be qualified, once the release mechanisms for a new material are determined.

The recent determination of the release mechanisms for silicate glasses and minerals provide a good illustration of this point. The rate-limiting step in silica-water reactions in a glass or mineral is breakage of the structural Si–O bonds (Oelkers, 2001; Oelkers et al., 1994; Rimstidt and Barnes, 1980). Oelkers (2001) has shown that the release mechanisms for single-phase minerals and glasses are similar. Thus, modeling of the dissolution of glass has paralleled the modeling of mineral-solution dissolution. Kinetic treatments have systematized the effects of pH, temperature, saturation state, ionic strength of the leachant, and inhibition on the overall release rate by developing models that treat each effect individually (Lasaga and Luttge, 2004). The kinetic effects of saturation state as a function of pH, temperature, and ionic strength have primarily been handled by the application of combined thermodynamic and kinetic TST models and the free energy dependence of basic irreversible dissolution reactions (Aagaard and

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9 This glass was originally developed as a standard for test method responses and later became a standard for glass durability (see Ebert and Wolf, 1999; Wolf et al., 1998).

Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
×

TABLE 5.1 Summary of Waste Form Durability Response and Tests

Waste Form Class Retention Mechanism
Single-Phase Glasses Chemical incorporation
 
Constituentsb are atomically bonded in the glass structure, usually to oxygen that is also bonded to other matrix elements (e.g., Si, Al, B, P) by short-range order (SRO) and medium-range order (MRO).
 
Glass-Ceramic Material Chemical incorporation
 
Constituents are present in the glass matrix and benign crystals such as spinels (Cr, Ni, and Fe species) are allowed to crystallize (images/nec-1-1.jpg). These crystals do not contain radionuclides but may contain hazardous constituents (e.g., Cr, Ni).
 
Glass-Ceramic Material Chemical incorporation and encapsulation
 
Constituents are present in the glass matrix and in the crystalline phases. Example shows Cs in the glass and in a secondary phase ( images/nec-1-2.jpg). Secondary phase may be more soluble than glass (e.g., (Na,Cs)2SO4) or more durable than glass (e.g., pollucite (Cs,Na)2Al2Si4O12).
 
Single-Phase Oxides/Minerals/Metals Chemical incorporation
 
Consists of only one main crystalline phase, which contains the same radionuclide(s). May be granular or monolithic.
Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
×
Graphical Representation Durability Behavior Appropriate Durability Test/Standardsa
images/nec-2-1.jpg single phase source – homogeneous glass ASTM C1220
ASTM C1285
ASTM C1662
ASTM C1663
PUF
EA, ARG-1, LRM, work for borosilicate-based GCMs; testing and standards must be developed for non-borosilicates
images/nec-2-2.jpg single phase source—homogeneous glass as long as crystalline phases do not sequester constituents ASTM C1220
ASTM C1285
ASTM C1662
ASTM C1663
PUF
EA, ARG-1, LRM, work for borosilicate based GCMs; testing and standards must be developed for non-borosilicates
images/nec-2-3.jpg multiphase source—glass and multiple crystalline phases and grain boundaries ASTM C1220
ASTM C1285
ASTM C1662
ASTM C1663
PUF
EA, ARG-1, LRM, work for borosilicate-based GCMs; testing and standards must be developed for non-borosilicates
images/nec-2-4.jpg multiphase source—single crystalline phase and grain boundaries ASTM C1220
ASTM C1285
ASTM C1662
ASTM C1663
PUF
Testing and standards must be developed
Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
×
Waste Form Class Retention Mechanism
Multiphase Oxides/Minerals/Metals Chemical incorporation
 
Individual phases contain one or multiple constituents (e.g., solid solution indicated between UO2 and ThO2). Some phases do not incorporate any constituents (gray shading). May be granular or monolithic.
 
Multiphase Granular Oxides/Minerals/Metals Chemical incorporation and encapsulation
 
Granular waste forms must be monolithed for disposal if not containerized. The monolithing agent does not incorporate constituents (gray shading). Also known as composite waste forms.
 
Cementation/Hydroceramics Geopolymers Encapsulation
 
Hydrated phases incorporate constituents weakly or retain them by sorption. Encapsulation is by solidification or precipitation of constituents on grain boundaries where non-constituent phases hydrate or crystallize. Example shows Tc sequestered by C-S-H hydrates and sequestered by secondary fly-ash granules.
 

NOTES: EA = Environment Assessment Glass; ARG-1 = Analytical Reference Glass-1; LRM

= Low-Activity Waste Reference Material.

a Standards are only appropriate if mechanisms and radionuclide releases are shown to be the same. The tests are described in Appendix 5.C.

b Can include both radioactive and chemical constituents.

Key:

images/img-3-1.jpg

   Cs   U   Tc   Pu

Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
×
Graphical Representation Durability Behavior Appropriate Durability Test/Standardsa
images/nec-4-1.jpg multiphase source—multiple crystalline phases and grain boundaries ASTM C1220
ASTM C1285
ASTM C1662
ASTM C1663
PUF
Testing and standards must be developed
images/nec-4-2.jpg multiphase source—multiple crystalline phases but binder and grain boundaries contain no constituents ASTM C1220
ASTM C1285
ASTM C1662
ASTM C1663
PUF
Testing and standards must be developed
ASTM C1308
or
ANSI 16.1 or
EPA 1315
images/nec-4-3.jpg multiphase source—multiple crystalline phases but phases encapsulate the constituents which exist primarily on the grain boundaries ASTM C1308
or
ANSI 16.1 or
EPA 1315
Radionuclides or simulants must be measured or a standard developed
Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
×

Helgeson, 1982; Apted, 1982; Grambow, 1985; Helgeson et al., 1984; Lasaga, 1984). These kinetic effects may not be the same for phosphate glasses or phosphate mineral waste forms, and surface-layer effects may also be different in these materials.

The TST and irreversible reaction models for mineral dissolution are being used to predict long-term dissolution of HLW glass in Yucca Mountain (Ebert, 2000) and release kinetics for the ILAW performance assessment at Hanford (Mann et al., 2001). In the TST treatment of durability of minerals and glasses, the rate-limiting step is considered to be the destruction of the slowest breaking metal-oxygen bonds, e.g., those that are essential for maintaining the mineral or glass structures such as (SiO4)–4, (AlO4)–5, and (FeO4)–5 (Oelkers, 2001; Oelkers et al., 1994).

The mechanisms of single-phase borosilicate glass dissolution are better defined now than 20 years ago. Advances have been made in understanding glass structure and how it controls release of radionuclides by establishing the distribution of ion exchange sites, hydrolysis sites, and the access of water to those sites. The access of water to the atomic sites through percolation channels (which are created by medium-range order; see Box 3.1) has only recently been determined. The role of the leached layer on controlling the long-term durability is still under investigation.

Some initial studies of glass structural control for non-borosilicate glasses (e.g., for phosphate glasses) have been published. The structural model for these glasses (Day et al., 1997) suggests that the sodium iron phosphate glasses can be visualized as consisting of PO4 tetrahedra joined together in various ways by oxygen polyhedra, which contain Fe2+, Fe3+, and/or sodium ions (if present). The structural model does not include percolation channels or evidence that iron phosphate glass releases constituents by a similar mechanism to borosilicate glass. Although the same testing protocols can be used on phosphate glass, the same glass durability standards may not be used unless the mechanistic interpretation of the test results are shown to be appropriate and/or the selection of a standard glass is shown to be an appropriate surrogate. The use of such a benchmarking material may not be necessary if the waste form test response can be related directly to its performance, but testing of radioactive release rates from iron phosphate glasses have yet to be completed and compared to borosilicate releases.

The qualification of a waste form for which the release mechanism is not known and existing standard tests have not been demonstrated to be appropriate is a detailed and laborious process. See, for example, Appendix 5.B, which illustrates the time and effort required for the qualification of borosilicate glass for immobilization of HLW at West Valley and the Savannah River Site. The process for qualifying new waste form materials is described in Section 5.4.

Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
×

5.3 STANDARD TEST PROTOCOLS

Waste form tests have been under development for decades. A brief discussion of the history of testing is provided in Appendix 5.A. A suite of standard tests, referred to as waste form test protocols, has been developed by the ASTM Subcommittee C26.13 on Spent Fuel and HLW10 and Subcommittee C26.07 on Nuclear Waste Materials:

  • C1174: Standard Practice for Prediction of the Long-Term Behavior of Materials, Including Waste Forms, Used in Engineered Barrier Systems (EBS) for Geological Disposal of High-Level Radioactive Waste
  • C1285: Standard Test Methods for Determining Chemical Durability of Nuclear, Hazardous, and Mixed Waste Glasses and Multiphase Glass Ceramics: The Product Consistency Test (PCT)
  • C1662: Standard Practice for Measurement of the Glass Dissolution Rate Using the Single-Pass Flow-Through Test Method
  • C1663: Standard Test Method for Measuring Waste Glass or Glass Ceramic Durability by Vapor Hydration Test
  • C1220: Standard Test Method for Static Leaching of Monolithic Waste Forms for Disposal of Radioactive Waste
  • C1308: Standard Test Method for Accelerated Leach Test for Diffusive Releases from Solidified Waste and a Computer Program to Model Diffusive, Fractional Leaching from Cylindrical Waste Forms

Additionally, three other standard tests also used for waste form testing:

  • PNNL Pressurized Unsaturated Flow (PUF) Test
  • ANSI 16.1: Measurement of the Leachability of Solidified Low-Level Radioactive Wastes by a Short-Term Test Procedure
  • EPA 1315: Mass Transfer Rates of Constituents in Monolithic or Compacted Granular Materials Using a Semi-Dynamic Tank Leaching Test

Several new ASTM test protocols are also under development; for example, a version of C1662 is being developed for spent nuclear fuel (SNF).

These tests are typically applied to small (kilogram mass or less) specimens of waste form materials. The material may be tested as a monolith or crushed to accelerate the test response. Testing protocols must be suitable

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10 The charter of ASTM Subcommittee C26.13 is to develop consensus standards in support of the national HLW disposal program.

Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
×

for the material to be tested. For example, for waste form materials that sequester constituents by encapsulation, crushing would partially destroy the encapsulation and produce a meaningless test response.

ASTM C1174 is a roadmap to waste form qualification and is discussed in detail in the next section. The remaining test protocols and their applicability to various waste form materials are described in Appendix 5.C.

5.4 WASTE FORM QUALIFICATION

The purpose of the ASTM C1174 practice is to guide the development of materials-behavior models that can be used to predict alterations in materials over the very long time periods (tens of thousands of years and more) pertinent to the operation of an HLW repository. Under the very extended periods relevant to geological disposal—much longer than those encountered in normal engineering practice—equilibrium or steady state conditions can be achieved, and models for reaction kinetics can be replaced by models describing equilibrium extents of alteration. The development of such models is an important step in qualifying new waste form materials for disposal.

ASTM C1174 has been under development and revision since the mid-1970s. It describes test methods and data analyses used to develop models for the prediction of the long-term behavior of materials, such as EBS materials and waste forms, used in the geologic disposal of SNF and HLW in a geologic repository. The alteration behavior of waste forms and EBS materials is important because it affects the retention of radioactive and hazardous constituents in a disposal system. The waste form and EBS materials provide barriers to release either directly, as in the case of waste forms in which the constituents are initially immobilized, or indirectly, as in the case of containment materials that restrict the ingress of groundwater or the egress of species that are released as the waste forms and EBS materials degrade. The waste form materials include, but are not limited to, glass, glass-ceramic, crystalline ceramics, oxides, and metallic waste forms.

ASTM C1174 lays out a roadmap (Figure 5.1) that shows the steps involved in predicting long-term behavior. The key steps are (1) problem definition, (2) testing, (3) modeling, and (4) model confirmation. An important aspect of C1174 is reiteration between testing and modeling, so these steps are intended to be carried out iteratively. The predictions are based on models derived from theoretical considerations, expert judgment, interpretation of data obtained from tests, and appropriate analogues. For the purpose of this practice, tests are categorized according to the information they provide and how such information is used for model development and use. These tests may include but are not limited to the following:

Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
×
images

FIGURE 5.1 Logic roadmap to qualification of a waste form in a licensed geologic repository in the United States.

SOURCE: From ASTM C1174-07.

Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
×
  • Attribute tests to measure intrinsic materials properties.
  • Characterization tests to measure the effects of material and environmental variables on behavior.
  • Tests to accelerate alteration and determine important mechanisms and processes that can affect the lifetime performance of waste form and EBS materials.
  • Service condition tests to confirm the appropriateness of the model and variables for anticipated disposal conditions.
  • Confirmation tests to verify the predictive capacity of the model.
  • Tests or analyses performed with analogue materials to identify important mechanisms, verify the appropriateness of an accelerated test method, and to confirm long-term model predictions.

ASTM C1174 identifies what type of information is needed from various test methods and how that information should be applied. For most waste forms, it is expected that several test methods will be needed to understand the degradation mechanism(s) well enough to develop a performance model. Many of the tests and analyses address multiple information needs.

For example, many tests provide insights into the waste form matrix degradation mechanism and radionuclide release mode (Ebert, 2008):

  • Identify the radionuclide release mechanism—tests must determine if the radionuclide is released congruently with the matrix or incongruently (Box 5.2). In most cases, these tests will serve to confirm the release mode based on an understanding of the matrix material and how the individual radionuclides are incorporated. Testing must determine if the release of various radionuclides is by diffusion (ion exchange), congruent dissolution of the matrix, or dissolution of the matrix to expose the phase containing the radionuclide, which then may dissolve or be released as a colloid.
  • Determine the matrix degradation mechanism—it is anticipated that radionuclides will be released by degradation of the waste form matrix, either physically or chemically. Dissolution of the matrix may be required before a radionuclide can be released, or it may simply need to be physically or chemically altered. Removal or reaction of a particular component in the matrix may be required to provide a pathway for release of the radionuclide. For some multi-phase waste forms, dissolution of an encapsulating material may be required before water can contact and react with the phase bearing the radionuclide. The durability of both the matrix and the radionuclide-bearing phase will then affect its release, and these may occur by different mechanisms.
Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
×

Many of the accelerated durability tests developed by ASTM have been in support of the testing block in Figure 5.1 with the purpose of accelerating the alteration of a waste form and determining the important release mechanisms. As noted previously, no one test gives all the information about alteration parameters and mechanisms; hence, various tests were developed to be used in conjunction with each other and with modeling.

5.5 DISCUSSION

State-of-the-art tests on waste form materials are used for a number of purposes, ranging from the investigation of degradation behavior and release of constituents to the parameterization of predictive models for waste form and disposal system performance. A large number of standard test protocols have been developed over the past three decades for these purposes. A key take-away message from this chapter is that these tests are material-specific, and no one test gives all the information needed to understand waste form properties or performance; indeed, a battery of tests must be used to understand waste form properties or performance.

Standard tests have been developed and qualified for use with borosilicate glass, glass-ceramic, and some crystalline ceramic materials. These tests can be applied to other waste form materials as part of experimental studies to investigate their degradation behavior. A standard testing protocol (ASTM C1174) has been established to qualify new waste form materials for use in disposal applications. However, the use of this protocol to qualify a waste form material for which the release mechanism is not known and existing standard tests have not been demonstrated to be appropriate is a detailed and laborious process.

Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
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APPENDIX 5.A
HISTORICAL DEVELOPMENT OF WASTE FORM TEST PROTOCOLS

In the early 1980s, the Office of Nuclear Waste Isolation (ONWI) under the Nuclear Waste Terminal Storage (NWTS) Program developed draft performance specifications and data requirements for mined geologic disposal of nuclear waste (ONWI 1981). Many of the requirements were for safe transportation of waste forms from their production sites to a geologic repository. The draft specifications required the following minimum information for waste forms:

  • Waste loading, including isotope inventory and heating rates
  • Radionuclide solubilities in various ground waters
  • Dissolution rates
  • Thermal properties
  • Mechanical strength properties
  • Radiation stability
  • Gas generation rates
  • Physical properties
  • Phase identification and composition

It was judged that this data would be sufficient to demonstrate the contribution that the waste form makes to the performance of the entire waste package (ONWI, 1981). ONWI required standardized, reproducible testing based on sound statistical principles to ensure high data quality.

In October 1979, DOE established the Materials Characterization Center (MCC) at the Pacific Northwest Laboratory (now the Pacific Northwest National Laboratory). The MCC developed tests (Mendel, 1983) for high-temperature vaporization of radionuclides (MCC-8), impact behavior (MCC-10), tensile strength (MCC-11), and chemical durability (MCC-1 through MCC-5) (see Table 5.A.1). Some of the durability protocols were static to mimic the slow flow of water in a flooded repository; some were dynamic to define a forward rate of maximum dissolution. Most were performed in three standard leachants: distilled water, WIPP Brine A, and a tuff groundwater representative of Yucca Mountain, Nevada. Results were always reported as normalized elemental mass loss in grams of test material per square meter of waste form surface area.

MCC-1 and MCC-2 have become ASTM C1220 (Standard Test Method for Static Leaching of Monolithic Waste Forms for Disposal of Radioactive Waste), MCC-3 has become ASTM C1285 (Standard Test Methods for Determining Chemical Durability of Nuclear, Hazardous, and Mixed Waste Glasses and Multiphase Glass Ceramics: The Product Consistency Test

Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
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TABLE 5.A.1 MCC Test Methods

Waste Form  
Chemical durability MCC-1, 2, 3, 4, 5
Aging effects (thermal and radiation) MCC-6, 7, 12, 13
Volatility MCC-8, 9, 16
Physical strength MCC-10, 11, 15
   
Canister Container  
Corrosion resistance MCC-101 102 103 104
   
Repository Interactions  
Canister/container corrosion MCC-105a
Waste form durability MCC-14a

a The repository interactions tests are divided into site-specific subcategories, e.g., MCC-105.1 (basalt).

(PCT)), MCC-4 has become ASTM C1662 (Standard Practice for Measurement of the Glass Dissolution Rate Using the Single-Pass Flow-Through Test Method), and MCC-5 is the Soxhlet durability test often performed in Europe to evaluate waste form durability. Additionally, the International Atomic Energy Agency has recommended for durability testing the International Standards Organization standard ISO 6961 (Long-Term Leach Testing of Solidified Radioactive Waste Forms). This leaching test was developed by the ISO and is similar to MCC-1 at normal (room) temperature.

Additional test protocols have been developed by the American Nuclear Standards Industry (ANSI) and by the U.S. Environmental Protection Agency (EPA). Some of the EPA leach protocols are designed to test the waste form response under adverse conditions1 to provide confidence that the release of hazardous species will meet the Universal Treatment Standards (UTS) under the Resource Conservation and Recovery Act (RCRA) Land Disposal Restrictions (LDR) regardless of whether the waste form was made from characteristically hazardous or listed wastes (see Chapter 8).

Although no specific test protocols exist for radiation damage, the existing leaching protocols can be used to test a waste form’s durability response both before and after radiation damage at a variety of doses. However, this approach may not reveal subtle effects, such as preferential etching, if the waste form dissolution rate is too rapid. In addition, the existing thermal stability protocols can be used in conjunction with the existing durability protocols to test a waste form’s durability before and after thermal treatment.

________________________

1 Acetic acid is used to simulate leaching under acidic conditions, such as what might occur in a landfill.

Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
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APPENDIX 5.B
QUALIFICATION OF HLW BOROSILICATE GLASS AND HLW GLASS PRODUCTION AT THE SAVANNAH RIVER SITE

1973 Waste form and process alternatives evaluation—concrete and glass
1975 Savannah River Site decision to use borosilicate glass for HLW immobilization
1976 Waste form and process selection-continuous glass production process
July 1982 DWPF Environmental Assessment released for public comment
Nov. 1983 Groundbreaking for the Defense Waste Processing Facility (DWPF)
1983 Initiated validation of glass performance (international burial testing)
Aug. 1984 DWPF construction began
1986 First waste compliance plan completed
1987-1994 Established reproducible glass performance test protocol (product consistency test)
Aug. 1988 Major DWPF construction efforts complete
Aug. 1989 DWPF operations began—component testing
1990 Established performance benchmark glass (EA Glass)
April 1994 Non-radioactive operations began—established control of the DWPF glass production process
1996 Radioactive operations began of DWPF
2010 Fourteen years of HLW glass production
Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
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APPENDIX 5.C
DURABILITY TEST PROTOCOLS

The test protocols listed in Section 5.3 are described in this appendix.

ASTM C1220 (MCC-1 AND MCC-2)

This test method provides a measure of the reactivity of a material in a dilute solution in which the test response is dominated by reaction of the specimen. The specimen is normally a monolith1 polished to 600-grit finish. The test is normally performed at temperatures of 40°C, 70°C, and 90°C in either deionized water or groundwater (actual or simulated). If multiple temperatures are tested the activation energy for dissolution can be measured for a given reaction time. Test durations vary; nominal is 28 days, but shorter periods of time (1, 3, 5, and 7 days) can be measured and used to determine a forward rate of reaction (Ebert, 2005), or longer-term tests up to several years can be conducted.

This test method can be used to compare the dissolution behaviors of candidate radioactive waste forms and to study their reactions during static exposure to dilute solutions in which solution feedback effects are small. Data from this test may form part of the larger body of data that is necessary in the logical approach to long-term prediction of waste form behavior, as described in ASTM C1174. In particular, solution concentrations and characterization and altered surfaces may be used in the testing of geochemical modeling codes. This test method can be used as either a “characterization” or “accelerated” test under the protocol of ASTM C1174 (see main text). Although it is not a formal part of the test method, the specimen can also be examined for surface alteration products to correlate with the solution results and study the reaction mechanism.

This test method is sensitive to the dissolution behavior of the waste form. The geometric surface area of a specimen can be measured to allow accurate calculation of the specific dissolution rate. The test is easy to run, can be conducted under a wide range of conditions, provides a large solution volume for analysis, and is economical. Short-term tests can be used to measure the effects of temperature, pH, and components in the leachant on the dissolution rate of materials that degrade by dissolution. Longer-term tests become affected by the affinity term and can be used to estimate the solubility of the waste form by regressing data with the rate expression.

________________________

1 This test method excludes the use of powdered specimens and organic materials.

Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
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ASTM C1285 (MCC-3)

This durability test method, commonly known as the Product Consistency Test (PCT), has two parts: PCT-A and PCT-B. The specimen is normally crushed to increase the surface area exposed to the test solution, which accelerates the evolution of the solution chemistry toward saturation (see Figure 5.C.1).2 PCT-A is a seven-day chemical durability test performed at 90°C in a leachant of ASTM-Type I water. The test method is static and conducted in stainless steel vessels. PCT-B is a durability test that allows testing at various test durations, temperatures, mesh size, mass of sample, leachant volume, and leachant composition, including simulated or actual groundwaters. This test method is static and can be conducted in stainless steel or Teflon vessels.

Together, PCT-A and PCT-B provide data for evaluating the chemical durability of glass waste forms as measured by elemental release. The glass waste forms are defined in the procedure as homogeneous glasses, phase separated glasses, devitrified glasses, glass ceramics, and/or multiphase glass-ceramic waste forms. Although this test has not been qualified for other types of waste form materials (e.g., cements), it is often used to determine dissolution mechanisms for other waste form types or used as a scoping test to compare waste forms or interpret mechanisms.

PCT-A can specifically be used to obtain data to evaluate whether the chemical durability of glass waste forms has been consistently controlled during production via the linking relationships discussed in Section 5.1 of this chapter. In the case of homogeneous borosilicate HLW glasses, acceptable performance is defined as an acceptably low dissolution rate, which is controlled by maintaining the glass composition within an acceptable range. The approach can be represented in terms of the linking relationships shown in Equation 5.1.

This linkage is appropriate for glass waste forms because the radionuclides are chemically bound within the glass structure and are released congruently as the glass dissolves. In general, for any waste form it must be established that control of performance in a laboratory test (i.e., the PCT) predicts acceptable control of performance in a disposal system based on performance tests, known mechanisms, and modeling.

PCT-B accelerated tests have been developed to provide data on longer-term performance of HLW borosilicate glass waste forms. PCT-B can specifically be used to measure the chemical durability of glass waste forms under various leaching conditions, for example, by increasing test durations, crushing of the solid waste form to increase the ratio of sample surface

________________________

2 Acceleration by increasing the surface area (SA) to volume (V) of leachant or the time duration of the test (t) is a common practice in waste form durability testing.

Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
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images

FIGURE 5.C.1 Example of static container for PCT.

SOURCE: Eric Pierce, Oak Ridge National Laboratory.

area (S) to solution volume (V), and using a variety of simulated or actual groundwater compositions. In addition, the temperature of the PCT-B type test can be increased to any temperature that does not alter the long-term dissolution mechanism to increase the dissolution rate and advance the overall progress of the waste form-groundwater reaction (Steefel et al., 2005).3

PCT-B tests can be used to determine radionuclide solubilities in various groundwaters; as an accelerated test to determine long-term dissolution rates of waste form materials; and to determine when solubility-limited concentrations for some radioelements are reached. The measurement of such concentrations provides crucial inputs to performance assessment of disposal systems. Thermodynamic databases are typically used to derive solubility-limiting phases for radioelements for all types of radioactive wastes in disposal systems (e.g., ANDRA, 2005; DOE, 2008; Nagra, 2002; NRC, 1996, 2005).

Such derivations are, however, complicated by factors such as metastability of precipitated radionuclide-bearing phases as well as the potential for co-precipitation of radionuclides as trace components in clay, zeolites, or other alteration phases (e.g., Apted, 1982; Bruno et al., 1997). Measurements from accelerated waste form testing of actual equilibrium or

________________________

3 With increasing temperature, it becomes critical that well-sealed test vessels are used so that no loss of water occurs arising from enhanced rates of evaporation. For test temperatures above 100°C, the internal water pressure of such sealed test vessels will move along the liquid-vapor (boiling) curve for water as defined by the imposed temperature, unless some external method (e.g., thin-walled, deformable metal “bags”; see Apted, 1982) are used to independently impose and control a higher test-system pressure to match pressure prevailing at appropriate repository depths.

Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
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steady-state concentrations of radionuclides can provide an important confirmation to the application thermodynamic databases. This raises the importance of continuing the development of advanced state-of-the-art solids and solutions analytical techniques in support of accelerated waste form testing (e.g., Pierce, 2008).

Data from PCT-B tests may form part of the larger body of data that are necessary for long-term prediction of waste form behavior (see Figure 5.1). PCT-B tests are useful for generating concentrated solutions to study chemical affinity effects on the dissolution rate. Tests at high temperatures and high glass/solution mass ratios can be used to promote the formation of alteration phases to (1) identify the kinetically favored alteration phases, (2) determine their propensity to sequester radionuclides, and (3) evaluate the effect of their formation on waste form dissolution rate. This information can be used to support the development of waste-form alteration models that can be coupled with relevant aqueous transport models to predict the release rate of radionuclides over the very long time periods pertinent to the operation of an HLW repository.

As noted previously, equilibrium or steady-state conditions may be achieved under the very extended service periods relevant to geological disposal. The same build-up of dissolved species that leads to a reduction in borosilicate dissolution rate also leads to saturation of the groundwater, with potential precipitation of both stable and radioactive dissolved species. At this point, the initial control of radionuclide release by reaction kinetics of the waste form would be replaced by solubility limits to radionuclide concentrations imposed by the initial crystalline waste form matrix, or by formation of new alteration products. The extended capabilities and flexibility of the PCT-B tests are intended to establish the various processes and associated data that control the release of radionuclides from disposal systems as waste forms react with groundwater over thousands of years and more.

ASTM C1662 (MCC-4)

This durability test method, known as the Single-Pass Flow-Through (SPFT) Test Method, is used for the measurement of glass dissolution rates. This test is most frequently used on homogeneous glasses, including nuclear waste glasses, in various test solutions at temperatures less than 100°C. The test procedure allows for inhomogeneous glasses (i.e., those that are phase separated or crystallized) to be studied provided the test response from each phase can be determined. The SPFT test is best suited for use with crushed materials, but tests can be conducted with monolithic specimens (Tole, 1982; Tole et al., 1986).

The SPFT test has been used for decades by geologists to measure the dissolution of minerals. It is commonly used for single-phase crystal-

Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
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line ceramics but has also been used for multiphase mineral waste forms (Icenhower et al., 2003; Jantzen et al., 2007; McGrail et al., 2003a,b; Zhao et al., 2000). Data interpretation is more complex with multiphase mineral waste forms because there are different source terms coming from the different mineral phases, unless comparisons can be made to the dissolution of single-phase natural analogue minerals and/or single-phase pure standards that have been tested for comparison. However the SPFT test is the most informative for characterization of a material’s leaching parameters and is recommended for determining the long-term dissolution of glass (Strachan, 2001).

SPFT tests may be conducted under conditions in which the effects from dissolved species on the dissolution rate are minimized to measure the forward dissolution rate at specific values of temperature and pH, or to measure the dependence of the dissolution rate on the concentrations of various solute species. This test can be used to characterize various aspects of corrosion behavior that can be utilized in a mechanistic model for calculating long-term behavior of a nuclear waste glass. Many of the parameters determined from this test, such as the activation energy of dissolution and the reaction progress, are used in the TST and irreversible intrinsic models developed for mineral dissolution (Helgeson et al., 1984; Oelkers, 2001; Oelkers et al., 1994).

The composition of the leachant solution can be controlled precisely, and dissolution rates can be measured fairly precisely (see Figure 5.C.2). The effects of the solution flow rate and sample surface area are taken into account when determining the dissolution rate using the rate equation for glass/mineral dissolution. The test method is appropriate for other materials that dissolve by the same mechanism, such as aluminosilicate minerals (Ebert, 2008). The test can be used to measure effects of various leachant components when waste solution volume is not a limitation (e.g., with nonradioactive materials).

The reacted sample recovered from a test may be examined with surface analytical techniques, such as scanning electron microscopy, to further characterize corrosion behavior. Such examinations may provide evidence whether the waste form is dissolving stoichiometrically or if particular leached layers and secondary phases were formed on the specimen surface. These occurrences may impact the accuracy of the glass dissolution rate that is measured using this method.

ASTM C1663

The vapor hydration test (VHT) (Ebert et al., 1991) is a static test in which a monolithic specimen is suspended in a sealed vessel with a small amount of water. When heated, the vapor phase becomes saturated, and a

Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
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images

FIGURE 5.C.2 Schematic of the SPFT test method.

SOURCE: Eric Pierce,Oak Ridge National Laboratory.

thin film of water condenses on the specimen. The amount of water in the vessel is carefully controlled so that no liquid remains. This is done to prevent solution from dripping off the specimen and establishing a reflux cycle and to maintain a static film of water on the specimen. Alteration phases formed on the reacted sample are analyzed, and thickness of the altered surface layer is measured on a cross-sectioned specimen.

The VHT can be used to study the corrosion of glass and glass ceramic waste forms under conditions of high temperature and contact by water vapor or thin films of water. This method may serve as an accelerated test for some materials, because the high temperatures will accelerate thermally activated processes. A wide range of test temperatures have been reported in the literature, from 40°C (e.g., Ebert et al., 2005) to 300°C (e.g., Vienna

Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
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et al., 2001). It should be noted that with increased test temperature comes the possibility of changing the corrosion rate-determining mechanism and the types of alteration phases formed from those that occur at lower temperatures such as in a particular disposal environment (Vienna et al., 2001).

The VHT can be used as a screening test to determine the propensity of waste forms to alter and for relative comparisons in alteration rates between waste forms. This test provides useful information regarding the alteration phases that are formed,4 the disposition of radioactive and hazardous components, and the alteration kinetics under the specific test conditions. This information may be used in performance assessment (e.g., Mann et al., 2001).

In a modification of the VHT, enough water is added to promote refluxing, and the solution is analyzed periodically to track the release of constituents. This provides very high specimen surface/volume ratios in a test with a monolithic specimen. This modification is similar to the Soxhlet test, except that the sample itself is used to condense the water vapor and maintain an adhering layer of water. Thus, the modified VHT method serves as a simplified flow-through test or Soxhlet test at elevated temperatures.

PNNL PUF TEST

The pressurized unsaturated flow (PUF) test (McGrail et al., 1997a) was developed at Pacific Northwest National Laboratory (PNNL) to simulate the flow of water/air mixtures in a hydrologically unsaturated environment. The test method is similar to the SPFT test in that the water/air mixture flow through a crushed sample and the effluent is collected periodically for analysis. The leachant can be pre-conditioned by placing other materials upstream of the sample, for example, to simulate interactions with geologic or engineering materials; interactions of released species can be simulated by placing other materials downstream of the sample. Reacted sample materials can be extracted and analyzed at the end of the test.

This test can be used to directly incorporate materials interactions in the test and simulate integrated hydrologically unsaturated systems. Leachant composition is controlled prior to contacting the specimen and the solution chemistry resulting from corrosion can be tracked during the test. Altered specimen and alteration phases can be collected for analysis after testing. This test is appropriate for confirmation testing of waste form corrosion mechanism in an integrated environment, regardless of whether it is hydrologically saturated or unsaturated. The method is not well-suited

________________________

4 The alteration phases that form in this test can be used as indicators of phases that might form under repository conditions.

Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
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for tests with monolithic specimens because of uncertainties in the water flow path and specimen contact.

The PUF test has not been standardized and is currently not conducted anywhere but PNNL, which has patented it (McGrail et al., 1999a). Some key uncertainties in the test are surface area of the crushed samples, preferential solution flow paths through sample, and possible modifications of the effluent prior to collection. The data resulting from several processes occurring in parallel or series can be difficult to relate to each specific process (McGrail et al., 1996, 1997a,b, 1999b).

ASTM C1308

ASTM C1308 accelerated leach test (ALT) is a modification of the ANS/ANSI 16.1 test method (see Figure 5.C.3) that can be used to (1) determine if the release of a component is controlled by diffusion and (2) determine the effective diffusion coefficient based on a model for diffusion from a finite cylinder. It is applicable to any matrix material that does not degrade or deform during the test, including cements and other monolithic waste forms. It is a semi-dynamic test in which a monolithic specimen of prescribed dimensions is immersed in a large volume of leachant in a sealed vessel for a relatively short interval. The leachate solution is periodically removed for analysis, and the sample is placed in fresh leachant to continue the test. The cumulative amounts of the species of interest released in successive test intervals are fitted with the diffusion equation for a finite cylinder. The test results can be used to qualitatively determine if the release of a component is controlled by diffusion alone, partitioned into a non-leachable fraction, or affected by solution saturation effects. Although evaluation of the diffusion coefficient requires use of a monolithic specimen having right cylinder geometry, the test method can be modified for use with crushed materials to determine (qualitatively) if releases are being controlled by diffusion.

This test provides for the determination of an effective diffusion coefficient using a mechanistic model. The method provides a procedure to determine if release from small or irregular specimens is controlled by diffusion or matrix dissolution, even though the specimens cannot be modeled to determine a diffusion coefficient from the test data. Very large volumes of waste solution can result from testing.

ANSI 16.1

This standard is similar to EPA Draft Method 1315 as well as ASTM C1308 (in fact, ANSI 16.1 preceded the ASTM C1308 standard). It provides for less frequent replenishment of the leachate and the calculation of a leaching index for various radionuclides (see Figure 5.C.3). The test

Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
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images

FIGURE 5.C.3 Schematic representation of the ANSI/ANS 16.1 test method. ASTM C1308 and EPA 1315 are similar but have more frequent replenishment frequencies.

SOURCE: EPA, 2009.

procedure is used to measure and index the release of radionuclides from waste forms as a result of dissolution in demineralized water for five days or longer. The results of this procedure do not apply to any specific environmental situation except through correlative studies of actual disposal site conditions. The test has by now become familiar to those working in the radioactive waste form development field.

EPA 1315

This test protocol (EPA, 2009) is a relatively new procedure that is still undergoing round robin testing. It is designed to provide the mass transfer rates (release rates) of inorganic analytes contained in a monolithic or compacted granular material under diffusion-controlled release conditions as a function of dissolution time. Observed diffusivity and tortuosity may be estimated through analysis of the resulting dissolution test data. The test is suitable to a wide range of solid materials, which may be monolithic (e.g., cements, solidified wastes) or compacted granular materials (e.g., soils, sediments, stacked granular wastes) that behave as a monolith in that the predominant water flow is around the material and release is controlled by diffusion to the boundary.

This test provides intrinsic material parameters for release of inorganic species under mass transfer-controlled dissolution conditions. It is intended as a means for obtaining a series of eluants, which may be used to estimate the diffusivity of constituents and physical retention parameter of the solid material under specified laboratory conditions.

EPA 1315 is a characterization method and does not utilize solutions considered to be representative of field conditions. This method is

Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
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similar in structure and use to predecessor methods ANSI/ANS 16.1 and ASTM C1308. However, this method differs from previous methods in that: (1) leaching intervals are modified to improve quality control, (2) sample preparation accounts for mass transfer from compacted granular samples, and (3) mass transfer may be interpreted by more complex release models that account for physical retention of the porous medium and chemical retention at the pore wall through geochemical speciation modeling.

Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
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REFERENCES

Aagaard, P. and H. C. Helgeson. 1982. “Thermodynamic and Kinetic Constraints on Reaction Rates Among Minerals and Aqueous Solutions, I. Theoretical Considerations,” Amer. J. Sci. 282, 237-285.

ANDRA [National Radioactive Waste Management Agency]. 2005. Dossier 2005 Argile. Tome: Safety Evaluation of a Geological Repository, ANDRA Report Series, Châtenay-Malabry, France.

Apted, M. J. 1982. “Overview of Hydrothermal Testing of Waste Package Barrier Materials at the Basalt Waste Isolation Project,” In Material Characterization Center Workshop on the Leaching Mechanisms of Nuclear Waste Forms, May 19-21, 1982, PNL-4382/UC-70, Pacific Northwest Laboratory, Richland, Wash.

Bates, J. K., D. J. Lam, and M. J. Steindler. 1983. “Extended Leach Studies of Actinide-Doped SRL 131 Glass,” In Scientific Basis for Nuclear Waste Management VI, D. G. Brookins (Ed.), North-Holland, New York, 183-190.

Bazan, F., J. Rego, and R. D. Aines. 1987. “Leaching of Actinide-doped Nuclear Waste Glass in a Tuff-Dominated System,” In Scientific Basis for Nuclear Waste Management X, J. K. Bates and W. B. Seefeldt (Eds.), Materials Research Society, Pittsburgh, Penn., 447-458.

Bibler, N. E. and A. R. Jurgensen. 1988. “Leaching Tc-99 from SRP Glass in Simulated Tuff and Salt Groundwaters,” In Scientific Basis for Nuclear Waste Management XI, M. J. Apted and R. E. Westerman (Eds.), Materials Research Society, Pittsburgh, Penn., 585-593.

Bibler, N. E. and J. K. Bates. 1990. “Product Consistency Leach Tests of Savannah River Site Radioactive Waste Glasses,” In Scientific Basis for Nuclear Waste Management XIII, V. M. Oversby and P. W. Brown (Eds.), Materials Research Society, Pittsburgh, Penn., 327-338.

Bradley, D. J., C. O. Harvey, and R. P. Turcotte. 1979. Leaching of Actinides and Technetium from Simulated High-Level Waste Glass, PNL-3152, Pacific Northwest Laboratory, Richland, Wash.

Bruno, J. and A. Sandino. 1987. Radionuclide Co-precipitation, SKB-TR-87-23, Swedish Spent Fuel and Nuclear Waste Management Co., Stockholm, Sweden

Crandall, J. L. 1983. “High Level Waste Immobilization,” In The Treatment and Handling of Radioactive Wastes, A. G. Blasewitz, J. M. Davis, and M. R. Smith (Eds.), Battelle Press and Springer-Verlag, 178-183.

Day, D. E., X. Yu, G. J. Long, and R. K. Brow. 1997. “Properties and Structure of Sodium-iron Phosphate Glasses,” J. Non-Cryst. Solids 215(1), 21-31.

DOE [U.S. Department of Energy]. 2008. Yucca Mountain Repository License Application: Safety Analysis Report, DOE/RW-0573, Rev 0., Office of Civilian Radioactive Waste Management, Las Vegas, Nev.

Ebert, W. L. 2000. Defense High Level Waste Glass Degradation, Office of Civilian Radioactive Waste Management Analysis/Model, ANL-EBS-MD-000016, Rev. 0 ICN01. (December).

Ebert, W. L. 2005. Testing to Evaluate the Suitability of Waste Forms Developed for Electrometallurgically-Treated Spent Sodium-Bonded Nuclear Fuel for Disposal in the Yucca Mountain Repository, ANL-05/43, Argonne National Laboratory, Argonne, Ill.

Ebert, W. L. 2008. Testing Protocols to Support Waste Form Development, Production, and Acceptance, GNEP-WAST-WAST-AI-RT-2008-000302, U.S. Department of Energy, Office of Nuclear Energy, Washington, D.C. (September).

Ebert, W. L., J. K. Bates, and W. L. Bourcier. 1991. “The Hydration of Borosilicate Waste Glass in Liquid Water and Steam at 200°C,” Waste Manage.11, 205-221.

Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
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Ebert, W. L., S. F. Wolf, and J. K. Bates. 1996. “The Release of Technetium from Defense Waste Processing Facility Glasses,” In Scientific Basis for Nuclear Waste Management XIX, W. M. Murphy and D. A. Knecht (Ed.), Materials Research Society, Pittsburgh, Penn., 221-227.

Ebert, W. L. and S. F. Wolf. 1999. Round-Robin Testing of a Reference Glass for Low-Activity Waste Forms, ANL-99/22, Argonne National Laboratory, Argonne, Ill.

EPA [U.S. Environmental Protection Agency]. 2009. Mass Transfer Rates of Constituents in Monolith or Compacted Granular Materials Using a Semi-Dynamic Tank Leaching Test, Draft Method 1315, Available at http://www.epa.gov/osw/hazard/testmethods/sw846/index.htm.

Fillet, S., J. Nogues, E. Vernaz, and N. Jacquet-Francillon. 1985. “Leaching of Actinides from the French LWR Reference Glass,” In Scientific Basis for Nuclear Waste Management IX, L. O. Werme (Ed.), Materials Research Society, Pittsburgh, Penn., 211-218.

Grambow, B. 1985. “A General Rate Equation for Nuclear Waste Glass Corrosion,” Mat. Res. Soc. Symp. Proc. 44, 15-27.

Grambow, B. and R. Muller. 2001. “First-order Dissolution Rate Law and the Role of Surface Layers in Glass Performance Assessment,” J. Nucl. Mat. 298, 112-124.

Helgeson, H. C., W. M. Murphy, and P. Aagaard. 1984. “Thermodynamic and Kinetic Constraints on Reaction Rates Among Minerals and Aqueous Solutions, II. Rate Constants, Effective Surface Area, and the Hydrolysis of Feldspar,” Geochim. et Cosmochim. Acta 48, 2405-2432.

Icenhower, J. P., D. M. Strachan, M. M. Lindberg, E. A. Rodriguez, and J. L. Steele. 2003. Dissolution Kinetics of Titanate-Based Ceramic Waste Forms: Results from Single-Pass Flow Tests on Radiation Damaged Specimens, PNNL-14252, Pacific Northwest National Laboratory, Richland, Wash. (May).

Jantzen, C. M., N. E. Bibler, D. C. Beam, and M. A. Pickett. 1993. Characterization of the Defense Waste Processing Facility (DWPF) Environmental Assessment (EA) Glass Standard Reference Material, WSRC-TR-92-346, Rev. 1, Westinghouse Savannah River Company, Aiken, S.C. (February).

Jantzen, C. M., N. E. Bibler, D. C. Beam, and M. A. Pickett. 1994. “Development and Characterization of the Defense Waste Processing Facility (DWPF) Environmental Assessment (EA) Glass Standard Reference Material,” In Environmental and Waste Management Issues in the Ceramic Industry, Ceram. Trans. 39, 313-322.

Jantzen, C. M., T. H. Lorier, J. M. Pareizs, and J. C. Marra. 2007. “Fluidized Bed Steam Reformed (FBSR) Mineral Waste Forms: Characterization and Durability Testing,” In Scientific Basis for Nuclear Waste Management XXX, D. Dunn (Ed.), 379-386.

Lasaga, A. C. 1984. “Chemical Kinetics of Water-Rock Interactions,” J. Geophys. Res. B6, 4009-4025.

Lasaga, A. C. and A. Luttge. 2004. “Mineralogical Approaches to Fundamental Crystal Dissolution Kinetics,” Amer. Mineral. 89, 527-540.

Mann, F. M., R. J. Puigh II, S. H. Finfrock, E. J. Freeman, R. Khaleel, D. H. Bacon, M. P. Bergeron, B. P. McGrail, S. K. Wurstner, K. Burgard, W. R. Root, and P. E. LaMont. 2001. Hanford Immobilized Low-Activity Tank Waste Performance Assessment: 2001 Version, DOE/ORP-2000-24, Rev. 0, U.S. Department of Energy, Office of River Protection, Richland, Wash.

McGrail, B. P. 1986. “Waste Package Component Interactions with Savannah River Defense Waste Glass in a Low-Magnesium Salt Brine,” Nucl. Tech. 168-186.

Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
×

McGrail, B. P., C. W. Lindenmeier, P. F. Martin, and G. W. Gee. 1996. “The Pressurized Unsaturated Flow (PUF) Test: A New Method for Engineered-Barrier Materials Evaluation,” In Environmental Issues and Waste Management Technologies in the Ceramic and Nuclear Industries II, 72, V. Jain and D. K. Peeler (Eds.), American Ceramic Society, Westerville, Ohio, 317-329.

McGrail, B. P., P. F. Martin, and C. W. Lindenmeier. 1997a. “Accelerated Testing of Waste Forms Using a Novel Pressurized Unsaturated Flow (PUF) Method,” Mat. Res. Soc. Symp. Proc. 465, 253-260.

McGrail, B. P., W. L. Ebert, A. J. Bakel, and D. K. Peeler. 1997b. “Measurement of Kinetic Rate Law Parameters on a Na-Ca-Al Borosilicate Glass for Low-Activity Waste,” J. Nucl. Mat. 249, 175-189.

McGrail, B. P., P. F. Martin, and C. W. Lindenmeier. 1999a. “Method and Apparatus for Measuring Coupled Flow, Transport, and Reaction Processes Under Liquid Unsaturated Flow Conditions,” Patent No. 5974859, Battelle Memorial Institute, Columbus, Ohio.

McGrail, B. P., C. W. Lindenmeier, and P. F. Martin. 1999b. “Characterization of Pore Structure and Hydraulic Property Alteration in Pressurized Unsaturated Flow Tests,” In Scientific Basis for Nuclear Waste Management XXII, D. J. Wronkiewicz and J. H. Lee (Eds.), Material Research Society, Pittsburgh, Penn., 421-428.

McGrail, B. P., H. T. Schaef, P. F. Martin, D. H. Bacon, E. A. Rodriguez, D. E. McCready, A. N. Primak, and R. D. Orr. 2003a. Initial Suitability Evaluation of Steam-Reformed Low Activity Waste for Direct Land Disposal, PNWD-3288, Battelle, Pacific Northwest Division, Richland, Wash.

McGrail, B. P., E. M. Pierce, H. T. Schaef, E. A. Rodriguez, J. L. Steele, A. T. Owen, and D. M. Wellman. 2003b. Laboratory Testing of Bulk Vitrified and Steam-Reformed Low-Activity Forms to Support a Preliminary Assessment for an Integrated Disposal Facility, PNNL-14414, Pacific Northwest National Laboratory, Richland, Wash.

Mendel, J. E. 1983. “Waste Glasses–Requirements and Characteristics,” In The Treatment and Handling of Radioactive Wastes, A. G. Blasewitz, J. M. Davis, and M. R. Smith (Eds.), Battelle Press, Columbus, Ohio, 178-183.

Nagra [National Cooperative for the Disposal of Radioactive Waste]. 2002. Demonstration of Disposal Feasibility for Spent Fuel, Vitrified High-Level Waste and Long-Lived Intermediate-Level Waste, TR-02-05, Nagra, Baden, Switzerland.

NRC [National Research Council]. 1996. The Waste Isolation Pilot Plant: A Potential Solution for the Disposal of Transuranic Waste, National Academy Press, Washington, D.C.

NRC. 2005. Tank Wastes Planned for On-Site Disposal at Three Department of Energy Sites: The Savannah River Site—Interim Report, National Academies Press, Washington, D.C.

Oelkers, E. H. 2001. “General Kinetic Description of Multioxide Silicate Mineral and Glass Dissolution,” Geochim. Cosmochim. Acta, 65(21), 3703-3719.

Oelkers, E. H., J. Schott, and J. L. Devidal. 1994. “The Effect of Aluminum, pH and Chemical Affinity on the Rates of Aluminosilicate Dissolution Reactions,” Geochim. Cosmochim. Acta 58, 2011-2024.

Ojovan, M. I. and W. E. Lee. 2005. An Introduction to Nuclear Waste Immobilisation, Elsevier, Amsterdam.

Ojovan, M. I., A. S. Pankov, and W. E. Lee. 2006. “The Ion Exchange Phase in Corrosion of Nuclear Waste Glasses,” J. Nucl. Mat. 358, 57-68.

ONWI [Office of Nuclear Waste Isolation]. 1981. Interim Performance Specifications for Waste Forms for Geologic Isolation, NWTS-19 DRAFT, Office of Nuclear Waste Isolation, Columbus, Ohio (October).

Suggested Citation:"5 Waste Form Testing." National Research Council. 2011. Waste Forms Technology and Performance: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/13100.
×

Pierce, E. M., B. P. McGrail, P. F. Martin, J. Marra, B. W. Arey, and K. N. Geiszler. 2007. “Accelerated Weathering of High-Level and Plutonium-Bearing Lanthanide Borosilicate Waste Glasses Under Hydraulically Unsaturated Conditions,” Appl. Geochem. 22(9), 1841-1859.

Plodinec, M. J. and W. G. Ramsey. 1994. “Glass Consistency and Glass Performance,” Spectrum 94 Proceedings, WSRC-MS-94-00311, Available at http://www.osti.gov/bridge/servlets/purl/10163781-GCJCOo/native/.

Rimstidt, J. D. and H. Z. Barnes. 1990. “The Kinetics of Silica-Water Reactions,” Geochim. Comochim. Acta 44, 1683-1699.

Steefel, C. I., D. J. DePaolo, and P. C. Lichtner. 2005. “Reactive Transport Modeling: An Essential Tool and a New Research Approach for the Earth Sciences,” Earth Planet. Sci. Lett. 240, 539-558.

Strachan D. M. 2001. “Glass Dissolution: Testing and Modelling for Long-Term Behaviour,” J. Nucl. Mat. 298, 69-77.

Tole, M. P. 1982. “Factors Controlling the Kinetics of Silicate-Water Interactions,” Unpublished PhD Thesis, The Pennsylvania State University, University Park, Penn. (March).

Tole, M. P., A. C. Lasaga, C. Pantano, and W. B. White. 1986. “The Kinetics of Dissolution of Nepheline (NaAlSiO4),” Geochim. Cosmochim. Acta 50(3), 379-392.

Vienna, J. D., P. Hrma, A. Kiricka, D. E. Smith, T. H. Lorier, I. A. Reamer, and R. L. Schulz. 2001. Hanford Immobilized LAW Product Acceptance Testing: Tanks Focus Area Results, PNNL-13744, Pacific Northwest National Laboratory. Richland, Wash.

Vernaz, E. Y. and N. Godon. 1992. “Leaching of Actinides from Nuclear Waste Glass: French Experience,” In Scientific Basis for Nuclear Waste Management XV, C. G. Sombret (Ed.), Materials Research Society, Pittsburgh, Penn., 37-48.

Weber, W. J., R. C. Ewing, and Lu-Min Wang. 1994. “The Radiation-Induced Crystalline-to-Amorphous Transition in Zircon,” J. Mat. Res. 9(3), 688-698.

Wolf, S. F., W. L. Ebert, J. S. Luo, and D. M. Strachan. 1998. A Data Base and a Standard Material for Use in Acceptance Testing of Low-Activity Waste Products, ANL-98/9, Argonne National Laboratory, Argonne, Ill.

Zhao, P., S. Roberts, and W. Bourcier. 2000. Technical Progress Report on Single Pass Flow Through Tests of Ceramic Waste Forms for Plutonium Immobilization, UCRLID-143361, Rev. 1, Lawrence Livermore National Laboratory, Livermore, Calif.

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The Department of Energy's Office of Environmental Management (DOE-EM) is responsible for cleaning up radioactive waste and environmental contamination resulting from five decades of nuclear weapons production and testing. A major focus of this program involves the retrieval, processing, and immobilization of waste into stable, solid waste forms for disposal. Waste Forms Technology and Performance, a report requested by DOE-EM, examines requirements for waste form technology and performance in the cleanup program. The report provides information to DOE-EM to support improvements in methods for processing waste and selecting and fabricating waste forms. Waste Forms Technology and Performance places particular emphasis on processing technologies for high-level radioactive waste, DOE's most expensive and arguably most difficult cleanup challenge. The report's key messages are presented in ten findings and one recommendation.

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