US4274976A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Treatment of high level nuclear reactor wastes
Assignee: Australian Atomic Energy Commission
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Filing: 1979-07-03
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Granted: 1981-06-23
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Expires: 1999-07-03
Abstract
Abstract A process for immobilizing high level radioactive waste (HLW) calcine comprises the steps of: (1) mixing the HLW calcine with a mixture of oxides, the oxides in the mixture and the relative proportions thereof being selected so as to form a mixture which, when heated and then cooled, crystallizes to produce a mineral assemblage containing well-formed crystals capable of providing lattice sites in which elements of the HLW are securely bound, the crystals belonging to or possessing crystal structures closely related to crystals belonging to mineral classes which are resistant to leaching and alteration in appropriate geological environments and including crystals belonging to the titanate classes of minerals; and (2) heating and then cooling the mixture so as to cause crystallization of the mixture to a mineral assemblage having the elements of the HLW incorporated as solid solutions within the crystals thereof. A mineral assemblage having elements of HLW calcine incorporated within the crystals thereof is also disclosed.
Inventors
- 👤 Alfred E. Ringwood
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 09:19
CPC Classifications
G; G21; G21F; G21F9/00; G21F9/28; G21F9/30; G21F9/301; G21F9/302
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
184 words
A process for immobilising high level radioactive waste (HLW) calcine which comprises the steps of: (1) mixing said HLW calcine in a minor proportion with a mixture of oxides, the oxides in said mixture and the relative proportions thereof being selected so as to form a mixture which, when heated and then cooled, crystallises to produce a mineral assemblage containing well-formed crystals capable of providing lattice sites in which elements of said HLW are securely bound, the crystals belonging to or possessing crystal structures closely related to crystals belonging to mineral classes which are resistant to leaching and alteration in appropriate geological environments and comprising crystals belonging to or possessing crystal structures closely related to at least two of the titanate mineral classes selected from the group consisting of perovskite (CaTiO 3 ), zirconolite (CaZrTi 2 O 7 ) and hollandite-type (BaAl 2 Ti 6 O 16 ) mineral classes; and (2) heating and then cooling said mixture so as to cause crystallisation of the mixture to a mineral assemblage having the elements of said HLW incorporated as solid solutions within the crystals thereof.
Claim 2
Dependent Claim
184 words
A process for immobilising high level radioactive waste (HLW) calcine which comprises the steps of: (1) mixing said HLW calcine in a minor proportion with a mixture of oxides, the oxides in said mixture and the relative proportions thereof being selected so as to form a mixture which, when heated and then cooled, crystallises to produce a mineral assemblage containing well-formed crystals capable of providing lattice sites in which elements of said HLW are securely bound, the crystals belonging to or possessing crystal structures closely related to crystals belonging to mineral classes which are resistant to leaching and alteration in appropriate geological environments and comprising crystals belonging to or possessing crystal structures closely related to at least two of the titanate mineral classes selected from the group consisting of perovskite (CaTiO 3 ), zirconolite (CaZrTi 2 O 7 ) and hollandite-type (BaAl 2 Ti 6 O 16 ) mineral classes; and (2) heating and then cooling said mixture so as to cause crystallisation of the mixture to a mineral assemblage having the elements of said HLW incorporated as solid solutions within the crystals thereof.
Claim 3
Dependent Claim
20 words
A process according to claim 1 wherein said minor proportion of said HLW calcine is less than 30% by weight.
Claim 4
Dependent Claim
18 words
A process according to claim 2, wherein said minor proportion of said HLW calcine is 5-20% by weight.
Claim 5
Dependent Claim
58 words
A process according to claim 1 wherein the oxides and the relative proportions thereof in said mixture of oxides are selected to form a mixture of oxides having a melting point of less than 1350° C., and said heating step comprises heating said mixture of HLW calcine and said oxides to a temperature sufficient to melt said mixture.
Claim 6
Dependent Claim
21 words
A process according to claim 1, wherein the heat treatment of said HLW/oxide mixture is carried out under mildly reducing conditions.
Claim 7
Dependent Claim
19 words
A process according to claim 5, wherein the heat treatment is carried out in the presence of a metal.
Claim 8
Dependent Claim
10 words
The process of claim 6 wherein said metal is nickel.
Claim 9
Dependent Claim
17 words
A process according to claim 5, wherein the heat treatment is carried out under a reducing atmosphere.
Claim 10
Dependent Claim
23 words
A process according to claim 8, wherein the reducing atmosphere is a gaseous atmosphere containing no free oxygen and containing a reducing gas.
Claim 11
Dependent Claim
14 words
The process of claim 9 wherein said reducing gas is hydrogen and/or carbon monoxide.
Claim 12
Dependent Claim
71 words
A process according to claim 1 wherein the oxides and the relative proportions thereof in the mixture of oxides are selected to that said mixture of oxides may be heated to a temperature in the range of 1000°-1500° C. without extensive melting of said mixture, and said heating step comprises heating said mixture of HLW calcine and said oxides to a temperature in the range of 1000°-1500° C. without extensive melting.
Claim 13
Dependent Claim
59 words
A process according to claim 1, wherein said mineral assemblage further contains crystals belonging to or possessing crystal structures closely related to at least one of the mineral classes selected from the group consisting of barium felspar (BaAl 2 Si 2 O 8 ), leucite (KAlSi 2 O 6 ), kalsilite (KAlSiO 4 ), and nepheline (NaAlSiO 4 ).
Claim 14
Dependent Claim
43 words
A process according to claim 12, wherein said mineral assemblage contains crystals belonging to, or possessing crystal structures closely related to a combination of mineral classes selected from the group of combinations consisting of perovskite-hollandite-barium felspar-zirconolite-leucite-kalsilite, perovskite-hollandite-barium felspar-zirconolite-leucite, perovskite-hollandite-barium felspar-kalsilite-zirconolite, and perovskite-hollandite-barium felspar-nepheline-zirconolite.
Claim 15
Dependent Claim
15 words
A process according to claim 13, wherein said mineral assemblage comprises a perovskite-zirconolite-hollandite-barium felspar-kalsilite-leucite composition.
Claim 16
Dependent Claim
68 words
A process according to claim 1, wherein said oxides comprise at least four members selected from the group consisting of CaO, TiO 2 , ZrO 2 , K 2 O, BaO, Na 2 O, Al 2 O 3 , SiO 2 and SrO, one of said members being TiO 2 and at least one of said members being selected from the sub-group consisting of BaO, CaO and SrO.
Claim 17
Dependent Claim
70 words
A process according to claim 15, wherein said mixture is comprised of at least five members selected from said group, one of said members being TiO 2 , at least one of said members being selected from the sub-group consisting of BaO, CaO and SrO, and at least one of said members being selected from the sub-group consisting of ZrO 2 , SiO 2 and Al 2 O 3 .
Claim 18
Dependent Claim
36 words
A process according to claim 15, wherein in said group of oxides from which said oxides are selected, Al 2 O 3 is replaced partly or completely by the oxides of Fe, Ni, Co or Cr.
Claim 19
Dependent Claim
30 words
A process according to claim 1 wherein said mineral assemblages correspond essentially to crystals belonging to, or possessing crystal structures closely related to the perovskite and the hollandite-type mineral classes.
Claim 20
Dependent Claim
30 words
A process according to claim 1, wherein said mineral assemblage consists essentially of crystals belonging to, or possessing crystal structures closely related to the zirconolite and the hollandite-type mineral classes.
Claim 21
Dependent Claim
31 words
A process according to claim 1 wherein said mineral assemblage consists essentially of crystals belonging to, or possessing crystal structures closely related to the perovskite, zirconolite and the hollandite-type mineral classes.
Claim 22
Dependent Claim
62 words
A process according to claim 1, wherein said oxides comprise at least three members selected from the group consisting of BaO, TiO 2 , ZrO 2 , K 2 O, CaO, Al 2 O 3 and SrO, one of said members being TiO 2 and at least one of said members being selected from the sub-group consisting of BaO, CaO and SrO.
Claim 23
Dependent Claim
67 words
A process according to claim 21 wherein said mixture is comprised of at least four members selected from said group, one of said members being TiO 2 , at least one of said members being selected from the sub-group consisting of BaO, CaO and SrO, and at least one of said members being selected from the sub-group consisting of ZrO 2 and Al 2 O 3 .
Claim 24
Dependent Claim
36 words
A process according to claim 21 wherein in said group of oxides from which said oxides are selected, Al 2 O 3 is completely or partly replaced by the oxides of Ni, Co, Fe or Cr.
Claim 25
Dependent Claim
108 words
A mineral assemblage containing a minor proportion of immobilised high level radioactive wastes, said assemblage comprising crystals belonging to or having crystal structures closely related to crystals belonging to mineral classes which are resistant to leaching and alteration in appropriate geological environments and comprising crystals belonging to or possessing crystal structures closely related to at least two of the titanate mineral classes selected from the group consisting of pervoskite (CaTiO 3 ), zirconolite (CaZrTi 2 O 7 ) and hollandite-type (BaAl 2 Ti 6 O 16 ) mineral classes, and said assemblage having elements of said high level radioactive waste incorporated as solid solutions within the crystals thereof.
Claim 26
Dependent Claim
108 words
A mineral assemblage containing a minor proportion of immobilised high level radioactive wastes, said assemblage comprising crystals belonging to or having crystal structures closely related to crystals belonging to mineral classes which are resistant to leaching and alteration in appropriate geological environments and comprising crystals belonging to or possessing crystal structures closely related to at least two of the titanate mineral classes selected from the group consisting of pervoskite (CaTiO 3 ), zirconolite (CaZrTi 2 O 7 ) and hollandite-type (BaAl 2 Ti 6 O 16 ) mineral classes, and said assemblage having elements of said high level radioactive waste incorporated as solid solutions within the crystals thereof.
Claim 27
Dependent Claim
56 words
A mineral assemblage according to claim 24, further containing crystals belonging to, or possessing crystal structures closely related to at least one of the mineral classes selected from the group consisting of barium felspar (BaAl 2 Si 2 O 8 ), leucite (KAlSi 2 O 6 ), kalsilite (KAlSiO 4 ), and nepheline (NaAlSiO 4 ).
Claim 28
Dependent Claim
40 words
A mineral assemblage according to claim 25 containing crystals belonging to, or possessing crystal structures closely related to a combination of mineral classes selected from the group of combinations consisting of perovskite-hollandite-barium felspar-zirconolite-leucite-kalsilite, perovskite-hollandite-barium felspar-zirconolite-leucite, perovskite-hollandite-barium felspar-kalsilite-zirconolite and perovskite-hollandite-barium felspar-nepheline-zirconolite.
Claim 29
Dependent Claim
25 words
A mineral assemblage according to claim 24, containing crystals belonging to, or possessing crystal structures closely related to a combination of the mineral classes perovskite-zirconolite-hollandite.
References Cited (Backward Citations)
US3000072A
Cited
US4172807A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-06-22 | 1984-12-22 | 1985-06-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-06-22 | 1988-12-22 | 1989-06-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-06-22 | 1992-12-22 | 1993-06-23 | $7700.00 | Window Closed / Lapsed |