Cermet waste forms for disposal of waste from advanced reactors

Abstract

Systems, methods, and techniques disclosed and contemplated herein relate to processing high level radioactive waste (HLW). Exemplary techniques are applicable to various fuel types, such as metal / chloride salt HLW streams from pyroprocessing of sodium bonded metallic fast reactor fuel; metal and halide salt HLW from molten salt reactors; and SiC / pyrolytic carbon from mechanically breached TRISO (tri -structural isotropic particle fuel) kernels with oxide fission products (FPs) from reprocessing. Exemplary waste forms are cermets.

Description

Attorney Docket No.210953-0005-WO01 CERMET WASTE FORMS FOR DISPOSAL OF WASTE FROM ADVANCED REACTORS CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application No.63 / 585,875 filed on September 27, 2023, and U.S. Provisional Patent Application No. 63 / 590,707 filed on October 16, 2023, the entire contents both of which are incorporated herein by reference. STATEMENT OF GOVERNMENT INTEREST

[0002] This invention was made with government support under DE-AR0001614 and DE- AC05-76RL01830 awarded by the Department of Energy. The government has certain rights in the invention. TECHNICAL FIELD

[0003] The present disclosure relates to materials, methods, and techniques for processing and immobilizing or encapsulating waste from nuclear reactor systems. More particularly, the present disclosure relates to cermet materials incorporating waste from nuclear reactor systems. INTRODUCTION

[0004] In the next decade, advanced nuclear reactors will be deployed around the world to meet an ever‐growing energy demand. During the operation of these nuclear reactors, metallic and salt waste will be produced at the back end of the fuel cycle. It is difficult, or prohibitively inefficient, to immobilize the diversity of high-level waste (HLW) into borosilicate glass, especially at high waste loadings (WL). The instant disclosure relates to waste forms to immobilize salt and metallic waste into a single waste form. SUMMARY

[0005] In one aspect, a method for generating a cermet material. An exemplary method may include: receiving and processing a metallic component, receiving and processing salt waste, forming a mixture comprising the metallic component powder and the oxyhalide, and consolidating the mixture at a temperature no greater than 1300 °C. The exemplary method mayAttorney Docket No.210953-0005-WO01 include reducing the metallic component to a Dv50 particle size between about 1 µm and about 100 µm, thereby generating a metallic component powder; when the salt waste comprises a chloride salt, either (i) converting the chloride salt to an oxychloride mineral (ceramic) or (ii) dehalogenating the chloride salt to convert the chloride salt to a phosphate or other oxide-based glass or ceramic; and when the salt waste comprises a fluoride salt, either (i) converting the fluoride salt to an oxyfluoride mineral (ceramic) or (ii) dehalogenating the fluoride salt to convert the fluoride salt to a phosphate or other oxide-based glass or ceramic.

[0006] In another aspect, a method for generating a cermet material is disclosed. An exemplary method may include receiving and processing a metallic component, comprising: reducing the metallic component to a Dv50 particle size between about 1 µm and about 100 µm, thereby generating a metallic powder; receiving a carbon-based waste stream comprising amorphous carbon, SiC, graphite, uranium carbide (UC) and other allotropes of carbon or carbide minerals; converting the carbon-based waste stream to a carbide ceramic phase; forming a mixture comprising the metallic powder and the carbide ceramic phase; and consolidating the mixture at a temperature no greater than 1300 °C.

[0007] In another aspect, a cermet material is disclosed. Exemplary cermet materials may comprise: 40-80 volume percent (vol%) of a metallic matrix; and 20-60 vol% of an oxide / oxyhalide based ceramic or glassy component dispersed throughout the metallic matrix, where the cermet material comprises a waste loading of at least 70 vol%.

[0008] In another aspect, a cermet material is disclosed. Exemplary cermet materials may comprise: 40-80 volume percent (vol%) of a metallic matrix; and 20-60 vol% of a carbide ceramic component dispersed throughout the metallic matrix, where the cermet material comprises a waste loading of at least 70 vol%.

[0009] Before any embodiments of the disclosure are explained in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The disclosure is capable of other embodiments and of being practiced or of being carried out in various ways.Attorney Docket No.210953-0005-WO01 BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 shows top, bottom, and side views of an experimentally generated pellet comprising 50 volume percent 316 stainless steel and 50 volume percent sodalite.

[0011] Figure 2 shows top, bottom, and side views of an experimentally generated pellet comprising 70 volume percent 316 stainless steel and 30 volume percent sodalite.

[0012] Figures 3A-3D show X-ray diffractograms of experimental products generated from chloride salts via reactions (7)-(10).

[0013] Figure 4 presents an X-ray diffractogram of an experimental product obtained from reaction (11).

[0014] Figure 5 presents an X-ray diffractogram of an experimental product obtained from reaction (12).

[0015] Figure 6a provides the phase assemblages of SS316 obtained from an experimental thermodynamic simulation. Figure 6b shows the calculated melting temperature of SS316 with varying amounts of carbon, boron, or carbon and boron.

[0016] Figure 7a shows X-ray diffraction patterns of SiC and Fe3C powders.

[0017] Figure 8a shows X-ray diffraction patterns of SiC powders produced by room temperature HEBM of graphite and Si powders. Materials were milled for 1 h to 12 h. Reflection positions of 3C-SiC (cubic) and Si are shown above. Figure 8b shows X-ray diffraction patterns of SiC powders produced from graphite and silicon by room temperature HEBM for 6 h compared to a 4 h heat treatment at 1500 °C. Reflection positions of 3C-SiC and graphite are shown above.

[0018] Figure 9 shows X-ray diffraction patterns of Fe3C powders produced by room temperature HEBM of graphite and Fe powders. Materials were milled for 1 h to 8 h. Reflection positions of Fe3C and Fe metal are shown above.

[0019] Figure 10 shows exemplary cermet materials generated by spark plasma sintering (SPS) at varying relative amounts of stainless steel to ZrO2 or SiC.

[0020] Figure 11a shows X-ray diffraction data for an experimental 50 / 50 volume % cermet material comprising stainless steel and zirconia (ZrO2). Figure 11b shows X-ray diffraction data for an experimental 70 / 30 volume % cermet material comprising stainless steel and zirconia (ZrO2). Figure 11c shows X-ray diffraction data for an experimental 50 / 50 volume % cermet material comprising stainless steel and SiC.Attorney Docket No.210953-0005-WO01

[0021] Figure 12 shows SEM micrograph images of experimental cermet materials comprising 50 / 50 volume % stainless steel and zirconia and 70 / 30 volume % stainless steel and zirconia.

[0022] Figure 13 shows SEM-EDS analysis of an experimental cermet material comprising 50 / 50 volume % stainless steel and zirconia.

[0023] Figure 14 shows backscatter SEM images of experimental cermet materials generated using spark plasma sintering, at various magnifications, and for various relative amounts of stainless steel, zirconia, and SiC.

[0024] Figure 15 shows SEM-EDS analysis of an experimental cermet material comprising 50 / 50 volume % stainless steel and SiC generated via spark plasma sintering.

[0025] Figure 16 shows X-ray diffraction data for pure sodalite powder.

[0026] Figure 17 shows X-ray diffraction data for an experimental cermet material comprising 50 / 50 volume % stainless steel and sodalite.

[0027] Figure 18 shows X-ray diffraction data for an experimental cermet material comprising 70 / 30 volume % stainless steel and sodalite.

[0028] Figure 19 shows SEM-EDS analysis of an experimental cermet material comprising 50 / 50 volume % stainless steel and sodalite.

[0029] Figure 20 shows SEM-EDS analysis of an experimental cermet material comprising 70 / 30 volume % stainless steel and sodalite.

[0030] Figure 21 shows a photograph of an experimentally generated CsNb2O5F material and X-ray diffraction data for the material.

[0031] Figure 22 shows X-ray diffraction data for an experimentally generated material comprising (Li,K,Na)8(Al6Si6O24)Cl2and (K,Na)AlSiO4.

[0032] Figure 23A and Figure 23B show SS:CsNb2O5F cermets at 50:50 volume % and 70:30 volume % sintered at 900 °C for 5 minutes.

[0033] Figure 24 shows X-ray diffraction data for an experimentally generated CsNb2O5F powder.

[0034] Figure 25A and Figure 25B show X-ray diffraction data for SS:CsNb2O5F cermets at 50:50 volume % and 70:30 volume % sintered at 900 °C for 5 minutes.

[0035] Figure 26A and Figure 26B show SEM micrographs for SS:CsNb2O5F cermets at 50:50 volume % and 70:30 volume % sintered at 900 °C for 5 minutes.Attorney Docket No.210953-0005-WO01

[0036] Figure 27 shows EDS analysis of SS:CsNb2O5F cermets at 50:50 volume % sintered at 900 °C for 5 minutes.

[0037] Figure 28 shows EDS analysis of SS:CsNb2O5F cermets at 70:30 volume % sintered at 900 °C for 5 minutes. DETAILED DESCRIPTION

[0038] Systems, methods, and techniques disclosed and contemplated herein relate to processing high level radioactive waste (HLW). Exemplary techniques are applicable to various fuel types, such as metal / chloride salt HLW streams from pyroprocessing of sodium bonded metallic fast reactor fuel; metal and halide salt HLW from molten salt reactors; and SiC / pyrolytic carbon from mechanically breached TRISO (tri-structural isotropic particle fuel) kernels with oxide fission products (FPs) from reprocessing.

[0039] Exemplary waste forms are cermets. Cermets are composite materials composed of ceramic and metallic phases that possess various properties, such as flexible capacity, high thermal / electrical conductivity, extra waste loading, robust durability and efficient fabricability. I. Definitions

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In case of conflict, the present document, including definitions, will control. Methods and materials are described below, although methods and materials similar or equivalent to those described herein can be used in practice or testing of the present disclosure. All publications, patent applications, patents and other references mentioned herein are incorporated by reference in their entirety. The materials, methods, and examples disclosed herein are illustrative only and not intended to be limiting.

[0041] The terms “comprise(s),” “include(s),” “having,” “has,” “can,” “contain(s),” and variants thereof, as used herein, are intended to be open-ended transitional phrases, terms, or words that do not preclude the possibility of additional acts or structures. The singular forms “a,” “an” and “the” include plural references unless the context clearly dictates otherwise. The present disclosure also contemplates other embodiments “comprising,” “consisting of” and “consisting essentially of,” the embodiments or elements presented herein, whether explicitly set forth or not.Attorney Docket No.210953-0005-WO01

[0042] The modifiers “about” or “approximately” used in connection with a quantity are inclusive of the stated value and has the meaning dictated by the context (for example, it includes at least the degree of error associated with the measurement of the quantity). These modifiers should also be considered as disclosing the range defined by the absolute values of the two endpoints. For example, the expression “from about 2 to about 4” also discloses the range “from 2 to 4.” The term “about” may refer to plus or minus 10% of the indicated number. For example, “about 10%” may indicate a range of 9% to 11%, and “about 1” may mean from 0.9-1.1. Other meanings of “about” may be apparent from the context, such as rounding off, so, for example “about 1” may also mean from 0.5 to 1.4.

[0043] For the recitation of numeric ranges herein, each intervening number there between with the same degree of precision is contemplated. For example, for the range of 6-9, the numbers 7 and 8 are contemplated in addition to 6 and 9, and for the range 6.0-7.0, the numbers 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, and 7.0 are contemplated. For another example, when a pressure range is described as being between ambient pressure and another pressure, a pressure that is ambient pressure is expressly contemplated.

[0044] Definitions of specific functional groups and chemical terms are described in more detail below. For purposes of this disclosure, the chemical elements are identified in accordance with the Periodic Table of the Elements, CAS version, Handbook of Chemistry and Physics, 104thEd., inside cover, and specific functional groups are defined as described therein.

[0045] As used herein, the term “fluidized bed reactor” means a reactor where fluid is passed through catalyst material at a sufficient speed to suspend the solid catalyst material. Typically, oxygen carrier solids may move in any direction, bounded by the walls of the reactor.

[0046] As used herein, the term “fixed bed reactor” means defined as a reactor where catalyst material is fixed in a packed bed. Fluid is passed through catalyst material, but the fluid does not suspend the catalyst material, as in a fluidized bed reactor.

[0047] As used herein, the term “moving bed reactor” means a reactor where catalytic material flows in a single direction, generally, from top to bottom. The fluid material can flow in the same direction as the catalytic material (co-current movement). The fluid material can flow in an opposite direction as the catalytic material (countercurrent movement).Attorney Docket No.210953-0005-WO01 II. Exemplary Materials

[0048] Exemplary cermet materials comprise a metallic matrix and either (a) oxide- or oxyhalide-based ceramics or (b) carbide-based ceramics. Exemplary metallic matrices serve as a primary phase in the cermet materials and encapsulate ceramic materials dispersed throughout the metallic component matrix. Exemplary amounts and types of various constituents are described in the sections below. A. Exemplary Amounts of Various Exemplary Constituents

[0049] Exemplary cermet materials are designed to immobilize salt and metallic waste from nuclear reactors into a waste form. Depending on the nuclear reactor technology, exemplary cermet materials may comprise various waste loading amounts. As used herein, “waste loading” means the volume or concentration of material that may be constituted as “hazardous waste” (per state or federal codes) incorporated into a waste form on a per unit basis.

[0050] Typically, exemplary cermet materials may comprise a waste loading of at least about 40 volume percent (vol%). In various implementations, exemplary cermet materials may comprise a waste loading of at least 40 vol%; at least 50 vol%; at least 60 vol%; or at least 70 vol%.

[0051] Exemplary metallic matrices may be present in cermet materials at about 40 vol% to about 80 vol%. In various implementations, exemplary metallic matrices may be present in cermet materials at 40-80 vol%; 40-60 vol%; 60-80 vol%; 50-70 vol%; 40-50 vol%; 50-60 vol%; 60-70 vol%; or 70-80 vol%. In various implementations, exemplary metallic matrices may be present in cermet materials at no less than 40 vol%; no less than 45 vol%; no less than 50 vol%; no less than 55 vol%; no less than 60 vol%; no less than 65 vol%; no less than 70 vol%; no less than 75 vol%; or no less than 80 vol%. In various implementations, exemplary metallic matrices may be present in cermet materials at no greater than 40 vol%; no greater than 45 vol%; no greater than 50 vol%; no greater than 55 vol%; no greater than 60 vol%; no greater than 65 vol%; no greater than 70 vol%; no greater than 75 vol%; or no greater than 80 vol%.

[0052] In some implementations, exemplary metallic matrices may further comprise a dopant. In those instances, exemplary metallic matrices may comprise dopant at an amount of about 0.1 weight percent (wt%) to about 5 wt%. In those instances, exemplary metallic matrices may comprise dopant at an amount of 0.1-5.0 wt%; 0.5-5.0 wt%; 1-5 wt%; 2-5 wt%; 3-5 wt%; 0.1-3 wt%; 0.1-2 wt%; or 0.1-1 wt%. In those instances, exemplary metallic matrices may compriseAttorney Docket No.210953-0005-WO01 dopant at an amount no greater than about 5 wt%; no greater than 4 wt%; no greater than 3 wt%; no greater than 2 wt%; no greater than 1 wt%; or no greater than 0.5 wt%. In those instances, exemplary metallic matrices may comprise dopant at an amount no less than 4 wt%; no less than 3 wt%; no less than 2 wt%; no less than 1 wt%; or no less than 0.5 wt%.

[0053] When present, exemplary cermet materials may comprise between about 20 vol% and about 60 vol% of an oxide / oxyhalide based ceramic or glassy component. In various implementations, when present, exemplary oxide / oxyhalide based ceramics or glassy components may be present in cermet materials at 20-60 vol%; 20-40 vol%; 40-60 vol%; 30-50 vol%; 20-30 vol%; 30-40 vol%; 40-50 vol%; or 50-60 vol%. In various implementations, when present, exemplary oxide / oxyhalide based ceramics or glassy components may be present in cermet materials at no less than 20 vol%; no less than 25 vol%; no less than 30 vol%; no less than 35 vol%; no less than 40 vol%; no less than 45 vol%; no less than 50 vol%; no less than 55 vol%; or no less than 60 vol%. In various implementations, when present, exemplary oxide / oxyhalide based ceramics or glassy components may be present in cermet materials at no greater than 20 vol%; no greater than 25 vol%; no greater than 30 vol%; no greater than 35 vol%; no greater than 40 vol%; no greater than 45 vol%; no greater than 50 vol%; no greater than 55 vol%; or no greater than 60 vol%.

[0054] When present, exemplary cermet materials may comprise between about 20 vol% and about 60 vol% of a carbide ceramic. In various implementations, when present, exemplary carbide ceramics may be present in cermet materials at 20-60 vol%; 20-40 vol%; 40-60 vol%; 30-50 vol%; 20-30 vol%; 30-40 vol%; 40-50 vol%; or 50-60 vol%. In various implementations, when present, exemplary carbide ceramics may be present in cermet materials at no less than 20 vol%; no less than 25 vol%; no less than 30 vol%; no less than 35 vol%; no less than 40 vol%; no less than 45 vol%; no less than 50 vol%; no less than 55 vol%; or no less than 60 vol%. In various implementations, when present, exemplary carbide ceramics may be present in cermet materials at no greater than 20 vol%; no greater than 25 vol%; no greater than 30 vol%; no greater than 35 vol%; no greater than 40 vol%; no greater than 45 vol%; no greater than 50 vol%; no greater than 55 vol%; or no greater than 60 vol%.Attorney Docket No.210953-0005-WO01 B. Exemplary Metallic Matrices and Metallic Components

[0055] Exemplary metallic matrices in exemplary cermet materials may comprise one or more types of metals. Exemplary metallic matrices result from processed metallic components.

[0056] Exemplary metallic components in cermet materials result from precursor materials. Precursor materials may be any metal-containing component from various advanced nuclear reactor types, such as sodium metal cooled reactors, molten salt reactors, and TRISO reactors. Non-limiting examples of precursor materials may include pipes, valves, heat exchangers, cladding, and moderators.

[0057] Precursor materials are processed to generate exemplary metallic component powders that have a consolidation temperature less than or equal to 1300 °C. As discussed in greater detail below, exemplary metallic powders have a Dv50 particle size between about 1 µm and about 100 µm.

[0058] In some instances, exemplary metallic component powders may comprise various stainless steels, such as HT-9 or 316 stainless steels. In some instances, exemplary metallic component powders may comprise various Hastelloys, such as Hastelloy N. In some instances, exemplary metallic component powders may comprise nickel-based alloys. In some instances, exemplary metallic matrices may comprise undissolved solids (UDS) comprising molybdenum (Mo), zirconium (Zr), epsilon, and / or99Tc.

[0059] As discussed above, in some instances, exemplary metallic matrices may comprise one or more dopants. Exemplary dopants may include boron (B), carbon (C), chromium (Cr), silicon carbide (SiC), or combinations thereof. C. Exemplary oxide / oxyhalide based ceramics or glassy components

[0060] Exemplary oxide / oxyhalide based ceramics or glassy components in exemplary cermet materials may comprise one or more constituents. Exemplary oxide / oxyhalide based ceramics or glassy components may result from various precursor materials.

[0061] Broadly, precursor materials may be salt waste comprising a chloride salt or salt waste comprising a fluoride salt. Exemplary chloride salts may include CaCl2, BaCl2, NaCl, LiCl, KCl, CsCl, RbCl, SrCl2, and / or LnCl3where Ln = yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), uranium (U), chromium (Cr), orAttorney Docket No.210953-0005-WO01 samarium (Sm)). Exemplary fluoride salts may include BaF2, CeF3, CsF, LaF3, NdF3, PrF3, SmF3, SrF2, YF3, EuF3, GdF3, SbF3, NiF2, and / or PmF3.

[0062] In some instances, precursor materials may be waste comprising phosphate minerals. Exemplary phosphate mineral waste stream may include Na3PO4, NdPO4, Cs3PO4, CePO4, Ba3P2O8, LaPO4, PrPO4, SmPO4, and / or CrPO4.

[0063] In various instances, the oxide / oxyhalide comprises an oxychloride-based glass or ceramic or phosphate. Exemplary oxychloride-based glass or ceramics may include, for instance, Ca2B5O9Cl, Ca2VO4Cl, Ca2PO4Cl, Ca5(VO4)3Cl; Na8(SiO4)6Cl2, Ba5(VO4)3Cl; Ba0.5Ca4.5(VO4)3Cl; BaVO3Cl; Ba2NaClP2O7, Nd2Ti3O8Cl2; Nd3Si2O8Cl, Li4(B7O12)Cl; LiFe(MoO4)Cl; and / or Ba3Li2V2O7Cl4.

[0064] In some instance, precursor materials for oxide / oxyhalide based ceramics or glassy components may comprise iodine-129 (129I).

[0065] In various instances, the oxide / oxyhalide comprises an oxyfluoride based glass or ceramic. Exemplary oxyfluoride-based glass or ceramics may include, for instance, CsNbO5F, Li0.50Be0.25Ca4.50(PO4)3F, CsNb2O5F.

[0066] In various instances, the oxide / oxyhalide comprises a phosphate-based glass or ceramic. Exemplary phosphate-based glass or ceramic material may include NaZr2(PO4)3. D. Exemplary carbide ceramics

[0067] Exemplary carbide ceramics in exemplary cermet materials may comprise one or more constituents. Exemplary carbide ceramics may result from various precursor materials. Broadly, precursor materials may be carbon-based waste such as carbides and carbon-14 (14C) wastes. In various instances, exemplary carbon-based waste may comprise one or more of: amorphous carbon, SiC, TiC, Ti3SiC2, graphite, uranium carbide (UC) and other allotropes of carbon or carbide minerals. E. Exemplary chemical and physical properties

[0068] The internal temperature gradient from decay is less pronounced in exemplary cermet materials than in glass or ceramic waste forms. Without being bound by a particular theory, it is theorized that because of the metallic matrix, exemplary cermets have ~7× higher thermal conductivity (k) than borosilicate glasses. Hence, exemplary cermets are expected to tolerateAttorney Docket No.210953-0005-WO01 higher decay heat than borosilicate glass. Without being bound by a particular theory, it is theorized that exemplary cermet materials will be more stable to radiation than borosilicate glass waste forms.

[0069] Exemplary cermet materials may be particularly suited for disposal in mined geological repositories and / or deep boreholes. In some instances, exemplary cermet materials may be generally cylindrical.

[0070] In some implementations, exemplary cermet materials may have a diameter between about 2 cm and about 38 cm. In various instances, exemplary cermet materials may have a diameter between 2 cm and 38 cm; between 2 cm and 17 cm; between 17 cm and 38 cm; between 2 cm and 10 cm; between 10 cm and 20 cm; or between 20 cm and 38 cm. In various instances, exemplary cermet materials may have a diameter no less than 2 cm; no less than 5 cm; no less than 10 cm; no less than 15 cm; no less than 20 cm; no less than 25 cm; no less than 31 cm; no less than 35 cm; or no less than 38 cm. In various instances, exemplary cermet materials may have a diameter no greater than 2 cm; no greater than 5 cm; no greater than 10 cm; no greater than 15 cm; no greater than 20 cm; no greater than 25 cm; or no greater than 31 cm; no greater than 35 cm; or no greater than 38 cm. III. Exemplary Methods

[0071] Exemplary methods of generating cermet materials are discussed below. Broadly, exemplary methods may comprise processing a contaminated metallic waste component, receiving and processing salt waste or carbon-based waste, forming a mixture comprising metallic waste component powder and either oxide, phosphate, oxyhalide or carbide material, and consolidating the mixture. Other embodiments may comprise more or fewer operations.

[0072] In some instances, exemplary methods generate cermet materials without first separating various types of waste materials, such as separating salt waste from metallic waste.

[0073] Processing a metallic component may include receiving the metallic component from a nuclear reactor site. Exemplary metallic components are discussed above, and may include pipes, valves, heat exchangers, and moderators.

[0074] The metallic component is processed to generate a metallic powder. Various methods known in the art may be used to reduce the size of the raw material (the metallic component) to aAttorney Docket No.210953-0005-WO01 metallic powder. Exemplary operations to generate metallic component powder may include crushing and milling. More than one metallic component may be processed at the same time.

[0075] Typically, exemplary metallic powders have a Dv50 particle size between about 1 µm and about 100 µm. In various instances, exemplary metallic powders have a Dv50 particle size between 1 µm and 100 µm; 1 µm and 50 µm; 50 µm and 100 µm; 25 µm and 75 µm; 1 µm and 20 µm; 20 µm and 40 µm; 40 µm and 60 µm; 60 µm and 80 µm; or 80 µm and 100 µm. In various instances, exemplary metallic powders have a Dv50 particle size no less than 1 µm; no less than 2 µm; no less than 5 µm; no less than 10 µm; no less than 15 µm; no less than 20 µm; no less than 30 µm; no less than 40 µm; no less than 50 µm; no less than 60 µm; no less than 70 µm; no less than 80 µm; no less than 90 µm; or no less than 100 µm. In various instances, exemplary metallic powders have a Dv50 particle size no greater than 1 µm; no greater than 2 µm; no greater than 5 µm; no greater than 10 µm; no greater than 15 µm; no greater than 20 µm; no greater than 30 µm; no greater than 40 µm; no greater than 50 µm; no greater than 60 µm; no greater than 70 µm; no greater than 80 µm; no greater than 90 µm; or no greater than 100 µm.

[0076] In some instances, processing the metallic component may further comprise doping the metal particles in the powder with a dopant. Exemplary dopants and relative amounts are discussed in greater detail above. Doping the metal particles may comprise mixing metallic powder with the dopant.

[0077] Exemplary methods also include receiving and processing waste. Typically, exemplary waste is high level radioactive waste (HLW). In some instances, the waste comprises salt waste. In some instances, the waste comprises carbon-based waste. In some instances, the waste comprises phosphate-based waste.

[0078] Typically, exemplary salt waste comprises a chloride salt and / or a fluoride salt. When the waste is salt waste comprising a chloride salt, exemplary methods include either (i) converting the chloride salt to an oxychloride mineral (ceramic) or (ii) dehalogenating the chloride salt to convert the chloride salt to a phosphate or other oxide-based glass or ceramic.

[0079] When the salt waste comprises a chloride salt, exemplary methods may include recovering37Cl, following reactions (1)-(3), where Me is a metallic ion (cation).

[0080] When the waste is salt waste comprising a fluoride salt, exemplary methods include either (i) converting the fluoride salt to an oxyfluoride mineral (ceramic) (for example, seeAttorney Docket No.210953-0005-WO01 reactions (4) and (5)) or (ii) dehalogenating the fluoride salt to convert the fluoride salt to a phosphate or other oxide-based glass or ceramic. 2 MeCl + 2 NH4H2PO4→ Me2O•P2O5(glass)+ 2 NH4Cl(g,l)+ 2 H2O(g)(1) MeCl2+ 2NH4H2PO4→ MeO•P2O5(glass)+ 2NH4Cl(g,l)+ 2 H2O(g)(2) 2 MeCl3 + 6 NH4H2PO4 → Me2O3•3P2O5(glass) + 6 NH4Cl(g,l) + 6 H2O(g) (3) CsF + Nb2O5→ CsNb2O5F (4) Li2BeF4(s) + 6 Ca3(PO4)2(s) → 4Li0.50Be0.25Ca4.50(PO4)3F(s) (5) Na3(PO4) + 4P2O5 + 6ZrO2 → 3NaZr2(PO4)3 (6)

[0081] The resulting alkali phosphate (Me2O•P2O5), alkaline-earth phosphate (MeO•P2O5) and rare-earth or actinide phosphates (Me2O3•3P2O5) (from reactions (1)-(3)) may be converted to a chemically durable borosilicate glassy waste form, an iron phosphate or aluminophosphate glassy waste form, or a combination thereof.

[0082] In some instances, the phosphates from reactions (1)-(3) may be converted to chemically durable ceramics, as shown in reaction (6).

[0083] When the waste is carbon-based waste, one or more processing operations may be performed on the carbon-based waste. For instance, various size reduction techniques may be used to reduce the size of the carbon-based waste to generate a carbon powder. Exemplary methods may include heating the carbon powder with other constituents, such as silicon and / or titanium, at a temperature between 1200 °C and 1300 °C in either a vacuum environment or in a reducing atmosphere.

[0084] After generating processed waste, exemplary methods include forming a mixture comprising the metallic component powder and the processed waste. Forming a mixture may include mixing particles of processed waste and metallic component powder such that the processed waste particles are dispersed throughout the metallic component powder.

[0085] In some instances, forming the mixture may include mixing in a planetary ball mill.

[0086] Forming a mixture comprising the metallic component powder and the processed waste is performed such that 40 vol% to 80 vol% of a resulting cermet material is a metallic matrix. Forming the mixture is performed such that 20 vol% to 60 vol% of the resulting cermet material is an oxide / oxyhalide based ceramic or glassy component or a carbide ceramic component.Attorney Docket No.210953-0005-WO01

[0087] After forming the mixture, exemplary methods include consolidating the mixture. Consolidating occurs at a temperature no greater than 1300 °C. Various methods may be use for consolidation. For instance, consolidating may be performed via spark plasma sintering, hot uniaxial pressing, hot isostatic pressing, or any other consolidation technique known in the art. IV. Experimental Examples

[0088] Various experiments were performed, and the results are described below. A. Cermet with metal matrix encapsulating dispersed ceramic phases

[0089] Cermet pellets were made using 316 stainless steel and sodalite (Na8(SiO4)6Cl2) powders. Mixtures of the 316 stainless steel and sodalite were sintered at 1000 °C for 5 minutes at 50 MPa.

[0090] Figure 1 shows top, bottom, and side views of an experimentally generated pellet comprising 50 volume percent 316 stainless steel and 50 volume percent sodalite. Figure 17 shows XRD data for an experimentally generated pellet comprising 50 volume percent 316 stainless steel and 50 volume percent sodalite. Figure 19 shows SEM-EDS data for an experimentally generated pellet comprising 50 volume percent 316 stainless steel and 50 volume percent sodalite.

[0091] Figure 2 shows top, bottom, and side views of an experimentally generated pellet comprising 70 volume percent 316 stainless steel and 30 volume percent sodalite. Figure 18 shows XRD data for an experimentally generated pellet comprising 70 volume percent 316 stainless steel and 30 volume percent sodalite. Figure 20 shows SEM-EDS data for an experimentally generated pellet comprising 70 volume percent 316 stainless steel and 30 volume percent sodalite. Figure 16 shows XRD data for various sodalite-based powder compositions. B. Conversion of halide salts into oxyhalide ceramics

[0092] Chloride salts likely to be present in the waste streams of advanced reactors were evaluated. The focus was on the salts with highest weight fractions in the waste, including CaCl2, BaCl2, and NaCl. Experiments achieved close to 100% conversion for some of these salts.

[0093] CaCl2was converted to Ca2B5O9Cl, Ca2VO4Cl, Ca2PO4Cl and Ca5(VO4)3Cl via reactions (7)-(10) below, respectively. The conversion efficiency of the reactions (calculated basedAttorney Docket No.210953-0005-WO01 on the quantitative X-ray diffraction analysis – XRD) varied between 85% – 100%. Figure 3A – Figure 3D show the X-ray diffractograms of the products obtained from reactions (7)-(10), respectively. ½ CaCl2 + 1½ CaO + 2½ B2O3 → Ca2B5O9Cl (~85% yield) at 800 °C for 12 h (7) ½ CaCl2+ 1½ CaO + ½ V2O5→ Ca2VO4Cl (100% yield) at 700 °C for 12 h (8) ½ CaCl2+ 1½ CaO + ½ P2O5→ Ca2PO4Cl (91% yield) at 900°C 12 h (9) ½ CaCl2 + 4½ CaO + 1½ V2O5 → Ca5(VO4)3Cl (100% yield) at 900 °C for 12 h (10)

[0094] BaCl2was converted to Ba5(VO4)3Cl via reaction (11). The conversion efficiency of the reaction is 93%. Figure 4 presents the X-ray diffractograms of the products obtained from reaction (11). ½ BaCl2 + 4½ BaO + 1½ V2O5 → Ba5(VO4)3Cl (93% yield) at 800 °C for 12 h (11)

[0095] NaCl was converted to Ca5(VO4)3Cl and Na2SO4via reaction (12). The conversion efficiency of the reaction is ~100%. Figure 5 presents the X-ray diffractograms of the products obtained from reaction (12). NaCl + ½ CaSO4+ 4½ CaO + 1½ V2O5→ Ca5(VO4)3Cl + ½Na2SO4(~100% yield) at 800 °C for 12 h (12)

[0096] Figure 22 shows X-ray diffraction data for an experimentally generated material comprising 92.6% (Li,K,Na)8(Al6Si6O24)Cl2 and 7.4% (K,Na)AlSiO4. C. Lowering metal component melting point

[0097] Iron is the dominant component (> 60%mass) in stainless steel. Minor additions (<5%mass) of carbon and boron can decrease the melting temperature of iron. As such, boron and carbon were chosen as the initial experimental additives to reduce the melting temperature of stainless steel 316 (SS316). The chemical composition of SS316 was analyzed by x-ray diffraction (XRD). This composition was used in the thermodynamic simulation to predict the melting temperature.Attorney Docket No.210953-0005-WO01

[0098] Thermodynamic simulations were developed for SS316 and [SS316 + additive] to understand the eutectic melting temperature. Thermo-Calc software was employed to produce thermodynamic simulations based on the CALPHAD method in conjunction with steel / Fe alloy database. The input parameters for these simulations included the chemical composition of SS316, additive content, and pressure. Figure 6A provides the phase assemblages of SS316 obtained from the thermodynamic simulation. The melting temperature of SS316 was 1420 °C. By running multiple thermodynamic simulations with a range of additive content, Figure 6B depicts how the addition of boron and carbon alters the melting temperature of SS316, demonstrating that both elements can lower the melting point of SS316 below 1300°C. Dual additives are more effective than single additive, which lower the melting temperature by another 50 °C. D. Converting carbon to carbide

[0099] Figure 7 shows x-ray diffraction patterns of SiC powders produced by high temperature processes. Specifically, Figure 7 shows SiC powder generated after processing starting material with stoichiometries of Si1.05C, at 1 hour at 1600 °C, 1500 °C, 1400 °C, and 1300 °C.

[0100] Commercially available graphite, silicon, and titanium powders were procured and characterized. The synthesis of TiC and SiC powders from carbon / titanium and carbon / silicon mixtures was investigated by a reactive high-energy ball milling (HEBM) process and high- temperature heat treatments, with produced powders examined by XRD and Raman spectroscopy. The impact of milling time (1 h to 40 h), the temperature of reaction (1300 °C to 1600 °C in an Ar atmosphere), and starting material stoichiometry (from 1:1 to 1.2:1 Si:C) on the conversion of carbon to carbide was examined. The presence of Fe3C in milled materials targeting TiC and SiC prompted the investigation into the formation of Fe3C by HEBM.

[0101] SiC formation by ball milling: Graphite was not observed by XRD after 2 h of milling, suggesting amorphization of the starting graphite. As the milling time was increased from 2 h to 6 h, the relative fraction of conversion of carbon to SiC increased, with little to no Si observed after this point (see Figure 8A). Figure 8A shows X-ray diffraction patterns of SiC powders produced by room temperature HEBM of graphite and Si powders. Materials were milled for 1 h to 12 h. Reflection positions of 3C-SiC (cubic) and Si are shown.

[0102] The produced powders were nano-sized and highly strained. Fe and Fe3C contaminants were observed in increasing fractions from 2 h onwards, originating from the stainless-steel millingAttorney Docket No.210953-0005-WO01 vial and media utilized. Longer milling regimes resulted in excessive Fe contamination with no increase in SiC formation. Preliminary Rietveld refinements of the XRD patterns show that conversion of >25% carbon was achieved. The poor crystallinity of the produced materials makes quantitative analysis difficult (see below).

[0103] SiC formation by high-temperature heat treatments: Si and C in the stoichiometry corresponding to SiC were initially reacted for 4 h at 1300 °C and 1400 °C with little conversion and incomplete conversion, respectively, as observed by XRD. Near-complete conversion to SiC was observed when the raw material mixture was heat treated for 4 h at 1500 °C (see Figure 8B), though a small fraction of unconverted graphite was still observed. Figure 8B shows X-ray diffraction patterns of SiC powders produced from graphite and silicon by room temperature HEBM for 6 h compared to a 4 h heat treatment at 1500 °C. Reflection positions of 3C-SiC and graphite are shown.

[0104] The addition of excess Si, with stoichiometries of Si1.05C, Si1.1, and Si1.2C, resulted in a reduction in the fraction of unconverted graphite. Rietveld refinements show that conversion of >25% carbon has been achieved.

[0105] TiC formation by ball milling: The formation of TiC from Ti and graphite powders was observed to be extremely slow with significant contamination with Fe and Fe3C. A significant fraction of graphite was still present after 12 h of milling, alongside TiC, Ti metal, Fe metal and Fe3C.

[0106] TiC formation by high temperature heat treatments: TiC did not form at any temperature examined (1300 °C to 1600 °C), with post-heat treatment materials comprising Ti metal and graphite only.

[0107] Fe3C formation by milling: Similar to the behavior observed for SiC, Fe3C was observed to form after 2 h of milling, with significant fractions of Fe3C seen after 6 h. Further milling did not increase the relative fraction of carbide (Figure 9). Figure 9 shows X-ray diffraction patterns of Fe3C powders produced by room temperature HEBM of graphite and Fe powders. Materials were milled for 1 h to 8 h. Reflection positions of Fe3C and Fe metal are shown. As seen for the SiC materials produced by HEBM, these materials were nanosized and highly strained, making in- depth analysis difficult (see below).

[0108] Fe3C formation by high temperature heat treatments: at all temperatures studied the material retrieved had partially (at 1300 °C) or fully (at ≥1400 °C) melted, in-line with the phasesAttorney Docket No.210953-0005-WO01 expected at these temperatures from examination of the Fe-C phase diagram (liquid + Fe3C at >1153 °C; liquid only at >1320 °C).

[0109] Because of the nanosized, highly strained nature of the materials produced by HEBM, diffraction-based phase quantification (i.e., Rietveld refinements) was challenging. The patterns observed for all phases were significantly broadened, resulting in extensive (and in some cases, complete) overlap of neighboring reflections, leading to a number of highly correlated parameters in the refinements. Further complicating this is the fact that, if present, some or all of the C may be amorphous and so not directly observable by diffraction-based methods, necessitating the use of indirect analysis (e.g., by use of an internal reference standard). E. Cermet composition evaluations

[0110] Commercially available powders of Stainless Steel 316 L (SS), Hastelloy X, SiC, ZrO2 and other oxide and halide salts were procured. Cermets (diameter: 20 mm) comprising SS–ZrO2and SS–SiC, with their concentration varying between 50:50 and 80:20 vol.%, were synthesized using spark plasma sintering (SPS) at temperatures ≤1300 ˚C. Figure 10 shows photographs of representative cermets (as prepared by SPS) with composition (vol.%) (a) 50 SS : 50 ZrO2; (b) 70 SS : 30 ZrO2; (c) 50 SS : 50 SiC; (d) 70 SS : 30 SiC.. According to the (theoretical and experimental) density measurements (Archimedes method), the cermet pellets were ≥60% densified.

[0111] The densified cermets were characterized by X-ray diffraction (XRD; Figure 11) and scanning electron microscopy – energy dispersive spectroscopy (SEM-EDS; Figure 12 and Figure 13). Figure 11A shows X-ray diffraction (XRD) data for a 50 / 50 volume % of stainless steel (SS) and zirconia (ZrO2) cermet. Figure 11B shows XRD pattern of a 70 / 30 vol. % of SS - ZrO2cermet. Figure 11C shows XRD pattern of 50 / 50 vol.% SS - SiC cermet. Figure 12 shows SEM analysis showing a comparison of encapsulation between different compositions (a) 50 / 50 vol% SS / ZrO2 and (b) 70 / 30 vol% SS / ZrO2. Figure 13 shows SEM-EDS analysis of 50 / 50 vol % SS / ZrO2cermet.

[0112] The XRD shows SS and ceramic as two distinct phases in the as produced cermets, while SEM-EDS images depict minimal chemical interaction between the metallic and ceramic phases. Further, as evident from the SEM-EDS images of the SS-ZrO2cermets (Figure 13), the higher fraction of metallic phase assists in the densification of the cermet by encapsulating the ceramic phase, thus, lowering the porosity.Attorney Docket No.210953-0005-WO01

[0113] Cermets (diameter: 20 mm) comprising SS-ZrO2 (50:50; vol.%) were prepared using HUP at temperatures ≤1300 ˚C. Physically, the produced cermets appear mechanically strong and well-densified.

[0114] Figure 14 shows backscatter SEM images of various SPS cermet samples with Magnifications Ranging from 250x to 500x. a) 50:50 SiC / SS, b) 35:65 SiC / SS, c) 20:80 SiC / SS, d) 50:50 ZrO2 / SS, e) 35:65 ZrO2 / SS, f) 20:80 ZrO2 / SS. Figure 15 is an SEM-EDS image of a 50:50 SiC / SS sample prepared via SPS. F. Volatilization of CsF

[0115] To minimize the volatilization of CsF, the fluoride-based waste stream comprising CsF, CeF3, BaF2, NdF3, LaF3, SmF3 and other fission products was reacted with Nb2O5 for the conversion of CsF to CsNbO5F, as shown in reaction (4). Reaction (4) above showed 100% conversion of cesium fluoride to CsNb2O5F at 600 °C for 12 hours. Figure 21 shows a photograph of the resulting CsNb2O5F material and X-ray diffraction pattern for the material.

[0116] Figure 23A and Figure 23B show SS:CsNb2O5F cermets at 50:50 volume % and 70:30 volume % sintered at 900 °C for 5 minutes. BaF2and LaF2were also added as per waste chemistry. Figure 24 shows X-ray diffraction data for an experimentally generated CsNb2O5F powder.

[0117] Figure 25A and Figure 25B X-ray diffraction data for show SS:CsNb2O5F cermets at 50:50 volume % and 70:30 volume % sintered at 900 °C for 5 minutes. Figure 26A and Figure 26B show SEM micrographs for SS:CsNb2O5F cermets at 50:50 volume % and 70:30 volume % sintered at 900 °C for 5 minutes. Figure 27 shows EDS analysis of SS:CsNb2O5F cermets at 50:50 volume % sintered at 900 °C for 5 minutes. Figure 28 shows EDS analysis of SS:CsNb2O5F cermets at 70:30 volume % sintered at 900 °C for 5 minutes. Exemplary Embodiments

[0118] For reasons of completeness, various aspects of the technology are set out in the following numbered embodiments: Embodiment 1. A method for generating a cermet material, the method comprising: receiving and processing a metallic component, comprising:Attorney Docket No.210953-0005-WO01 reducing the metallic component to a Dv50 particle size between about 1 µm and about 100 µm, thereby generating a metallic component powder; receiving and processing salt waste, comprising: when the salt waste comprises a chloride salt, either (i) converting the chloride salt to an oxychloride mineral (ceramic) or (ii) dehalogenating the chloride salt to convert the chloride salt to a phosphate or other oxide-based glass or ceramic; when the salt waste comprises a fluoride salt, either (i) converting the fluoride salt to an oxyfluoride mineral (ceramic) or (ii) dehalogenating the fluoride salt to convert the fluoride salt to a phosphate or other oxide-based glass or ceramic; forming a mixture comprising the metallic component powder and the oxyhalide; and consolidating the mixture at a temperature no greater than 1300 °C. Embodiment 2. The method according to Embodiment 1, wherein receiving and processing the metallic component further comprises doping the metal particles in the powder with a dopant, thereby lowering the consolidation temperature of the metallic powder to ≤1300 °C. Embodiment 3. The method according to Embodiment 2, wherein the dopant comprises boron (B), carbon (C), chromium (Cr), silicon carbide (SiC), or combinations thereof. Embodiment 4. The method according to Embodiment 3, wherein the temperature is less than or equal to 1200 °C. Embodiment 5. The method according to Embodiment 4, wherein metal-ceramic mixture is consolidated via spark plasma sintering, hot uniaxial pressing, hot isostatic pressing, or any other consolidation technique, thereof. Embodiment 6. The method according to Embodiment 5, further comprising, when the salt waste comprises a chloride salt, recovering37Cl.Attorney Docket No.210953-0005-WO01 Embodiment 7. The method according to Embodiment 6, wherein the temperature is less than or equal to 1200 °C. Embodiment 8. A method for generating a cermet material, the method comprising: receiving and processing a metallic component, comprising: reducing the metallic component to a Dv50 particle size between about 1 µm and about 100 µm, thereby generating a metallic powder; receiving a carbon-based waste stream comprising amorphous carbon, SiC, graphite, uranium carbide (UC) and other allotropes of carbon or carbide minerals; converting the carbon-based waste stream to a carbide ceramic phase; forming a mixture comprising the metallic powder and the carbide ceramic phase; and consolidating the mixture at a temperature no greater than 1300 °C. Embodiment 9. The method according to Embodiment 8, wherein receiving and processing the metallic component further comprises doping the metal particles in the powder with a dopant, thereby lowering the consolidation temperature of the metallic powder to ≤1300 °C. Embodiment 10. The method according to Embodiment 9, wherein the dopant comprises boron (B), carbon (C), chromium (Cr), silicon carbide (SiC), or combinations thereof. Embodiment 11. The method according to Embodiment 10, wherein the temperature is less than or equal to 1200 °C. Embodiment 12. The method according to Embodiment 11, wherein metal-ceramic mixture is consolidated via spark plasma sintering, hot uniaxial pressing, hot isostatic pressing, or any other consolidation technique, thereof. Embodiment 13. A cermet material, comprising 40-80 volume percent (vol%) of a metallic matrix; andAttorney Docket No.210953-0005-WO01 20-60 vol% of an oxide / oxyhalide based ceramic or glassy component dispersed throughout the metallic matrix, the cermet material comprising a waste loading of at least 70 vol%. Embodiment 14. The cermet material according to Embodiment 13, the metallic matrix further comprising a dopant. Embodiment 15. The cermet material according to Embodiment 14, wherein the dopant comprises boron (B), carbon (C), chromium (Cr), silicon carbide (SiC), or combinations thereof. Embodiment 16. The cermet material according to Embodiment 15, the dopant being present in the metallic matrix at an amount no greater than 5 wt%. Embodiment 17. The cermet material according to Embodiment 16, the dopant being present in the metallic matrix at an amount no greater than 2.0 wt%. Embodiment 18. The cermet material according to Embodiment 17, wherein the metallic component has a consolidation temperature less than 1300 °C. Embodiment 19. The cermet material according to Embodiment 18, the oxyhalide component comprising an oxychloride-based glass or ceramic. Embodiment 20. The cermet material according to Embodiment 19, the oxyhalide component comprising an oxyfluoride based glass or ceramic. Embodiment 21. The cermet material according to Embodiment 20, the ceramic component comprising a phosphate or other oxide-based glass or ceramic. Embodiment 22. A cermet material, comprising: 40-80 volume percent (vol%) of a metallic matrix; and 20-60 vol% of a carbide ceramic component dispersed throughout the metallic matrix,Attorney Docket No.210953-0005-WO01 the cermet material comprising a waste loading of at least 70 vol%. Embodiment 23. The cermet material according to Embodiment 22, the metallic matrix further comprising a dopant. Embodiment 24. The cermet material according to Embodiment 23, wherein the dopant comprises boron (B), carbon (C), chromium (Cr), silicon carbide (SiC), or combinations thereof. Embodiment 25. The cermet material according to Embodiment 24, the dopant being present in the metallic matrix at an amount no greater than 5 wt%. Embodiment 26. The cermet material according to Embodiment 25, the dopant being present in the metallic matrix at an amount no greater than 2.0 wt%. Embodiment 27. The cermet material according to Embodiment 26, wherein the metallic component has a consolidation temperature less than 1300 °C. Embodiment 28. The cermet material according to Embodiment 27, the ceramic component comprising a phosphate or other oxide-based glass or ceramic.

[0019] It is understood that the foregoing detailed description and accompanying examples are merely illustrative and are not to be taken as limitations upon the scope of the disclosure. Various changes and modifications to the disclosed embodiments will be apparent to those skilled in the art. Such changes and modifications, including without limitation those relating to the chemical structures, substituents, derivatives, intermediates, syntheses, compositions, formulations, pressure, and temperature adjustments, separation, recovery, or methods of use, may be made without departing from the spirit and scope of the disclosure.

Claims

Attorney Docket No.210953-0005-WO01 CLAIMS 1. A method for generating a cermet material, the method comprising: receiving and processing a metallic component, comprising: reducing the metallic component to a Dv50 particle size between about 1 µm and about 100 µm, thereby generating a metallic component powder; receiving and processing salt waste, comprising: when the salt waste comprises a chloride salt, either (i) converting the chloride salt to an oxychloride mineral (ceramic) or (ii) dehalogenating the chloride salt to convert the chloride salt to a phosphate or other oxide-based glass or ceramic; and when the salt waste comprises a fluoride salt, either (i) converting the fluoride salt to an oxyfluoride mineral (ceramic) or (ii) dehalogenating the fluoride salt to convert the fluoride salt to a phosphate or other oxide-based glass or ceramic; forming a mixture comprising the metallic component powder and the oxyhalide; and consolidating the mixture at a temperature no greater than 1300 °C.

2. The method according to claim 1, wherein receiving and processing the metallic component further comprises doping the metal particles in the powder with a dopant, thereby lowering the consolidation temperature of the metallic powder to ≤1300 °C.

3. The method according to claim 2, wherein the dopant comprises boron (B), carbon (C), chromium (Cr), silicon carbide (SiC), or combinations thereof.

4. The method according to claim 3, wherein the temperature is less than or equal to 1200 °C.

5. The method according to claim 4, wherein metal-ceramic mixture is consolidated via spark plasma sintering, hot uniaxial pressing, hot isostatic pressing, or any other consolidation technique, thereof.Attorney Docket No.210953-0005-WO01 6. The method according to claim 5, further comprising, when the salt waste comprises a chloride salt, recovering37Cl.

7. The method according to claim 6, wherein the temperature is less than or equal to 1200 °C.

8. A method for generating a cermet material, the method comprising: receiving and processing a metallic component, comprising: reducing the metallic component to a Dv50 particle size between about 1 µm and about 100 µm, thereby generating a metallic powder; receiving a carbon-based waste stream comprising amorphous carbon, SiC, graphite, uranium carbide (UC) and other allotropes of carbon or carbide minerals; converting the carbon-based waste stream to a carbide ceramic phase; forming a mixture comprising the metallic powder and the carbide ceramic phase; and consolidating the mixture at a temperature no greater than 1300 °C.

9. The method according to claim 8, wherein receiving and processing the metallic component further comprises doping the metal particles in the powder with a dopant, thereby lowering the consolidation temperature of the metallic powder to ≤1300 °C.

10. The method according to claim 9, wherein the dopant comprises boron (B), carbon (C), chromium (Cr), silicon carbide (SiC), or combinations thereof.

11. The method according to claim 10, wherein the temperature is less than or equal to 1200 °C.

12. The method according to claim 11, wherein metal-ceramic mixture is consolidated via spark plasma sintering, hot uniaxial pressing, hot isostatic pressing, or any other consolidation technique, thereof.Attorney Docket No.210953-0005-WO01 13. A cermet material, comprising 40-80 volume percent (vol%) of a metallic matrix; and 20-60 vol% of an oxide / oxyhalide based ceramic or glassy component dispersed throughout the metallic matrix, the cermet material comprising a waste loading of at least 70 vol%.

14. The cermet material according to claim 13, the metallic matrix further comprising a dopant.

15. The cermet material according to claim 14, wherein the dopant comprises boron (B), carbon (C), chromium (Cr), silicon carbide (SiC), or combinations thereof.

16. The cermet material according to claim 15, the dopant being present in the metallic matrix at an amount no greater than 5 wt%.

17. The cermet material according to claim 16, the dopant being present in the metallic matrix at an amount no greater than 2.0 wt%.

18. The cermet material according to claim 17, wherein the metallic component has a consolidation temperature less than 1300 °C.

19. The cermet material according to claim 18, the oxyhalide component comprising an oxychloride-based glass or ceramic.

20. The cermet material according to claim 19, the oxyhalide component comprising an oxyfluoride based glass or ceramic.

21. The cermet material according to claim 20, the ceramic component comprising a phosphate or other oxide-based glass or ceramic.

22. A cermet material, comprising:Attorney Docket No.210953-0005-WO01 40-80 volume percent (vol%) of a metallic matrix; and 20-60 vol% of a carbide ceramic component dispersed throughout the metallic matrix, the cermet material comprising a waste loading of at least 70 vol%.

23. The cermet material according to claim 22, the metallic matrix further comprising a dopant.

24. The cermet material according to claim 23, wherein the dopant comprises boron (B), carbon (C), chromium (Cr), silicon carbide (SiC), or combinations thereof.

25. The cermet material according to claim 24, the dopant being present in the metallic matrix at an amount no greater than 5 wt%.

26. The cermet material according to claim 25, the dopant being present in the metallic matrix at an amount no greater than 2.0 wt%.

27. The cermet material according to claim 26, wherein the metallic component has a consolidation temperature less than 1300 °C.

28. The cermet material according to claim 27, the ceramic component comprising a phosphate or other oxide-based glass or ceramic.

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