CA1088439A - Container for radioactive nuclear waste materials - Google Patents
Container for radioactive nuclear waste materialsInfo
- Publication number
- CA1088439A CA1088439A CA325,367A CA325367A CA1088439A CA 1088439 A CA1088439 A CA 1088439A CA 325367 A CA325367 A CA 325367A CA 1088439 A CA1088439 A CA 1088439A
- Authority
- CA
- Canada
- Prior art keywords
- container
- alloy
- recited
- awaruite
- josephinite
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Processing Of Solid Wastes (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Containers composed of nickel-iron alloys such as those natural minerals produced under thermodynamically stable conditions within serpentinite-type rocks and possessing a composition in the range exhibited by the minerals awaruite and josephinite. Radioactive nuclear waste can be contained over extended periods of time by encapsulating the waste materials in containers composed of these alloys and burying the containers underground in an impervious, stable rock formation.
Containers composed of nickel-iron alloys such as those natural minerals produced under thermodynamically stable conditions within serpentinite-type rocks and possessing a composition in the range exhibited by the minerals awaruite and josephinite. Radioactive nuclear waste can be contained over extended periods of time by encapsulating the waste materials in containers composed of these alloys and burying the containers underground in an impervious, stable rock formation.
Description
~ ~8~43~
FIELD OF THE INVENTION
This invention relates to improved nuclear waste container materials possessing high corros:ion resistance when buried in natural rock formations. Integr:ity is obtained by the use of alloys which are thermodynamically stable in the geochemical environment of natural underground rock systems.
_ACKGROUND OF THE INVENTION -Modern nuclear reactors produce highly radioactive fission products and actinide elements which must be prevented from entering the biosphere over periods ranging from 10 to 1,000,000 years. The current policy and practice is to convert these high-level nuclear wastes to solid forms such as glasses or ceramic~, which are ~hen encapsulated in metal containers and buried underground in impervious, stable rock formations.
There are a great many patents directed to the structure of containers for nuclear wastes. Most contain only brief disclosures of the materials from which the containers are made. Stainless steël is named repeatedly as well as iron, steel~ lead, concrete, steel lined with copper, brass, zirconium alloy, cadmium, tantalum, tungsten, mercury, moly-bdenum, and sandwich ;
. ' ' .
,'~':.~, ' ~' ' .;' ',..
'': ~'`. ' ,' '. '."." .
-1- : '.' ~ ' ' ' .,:
8~435~
constructions employing various gels and flbers between layers of metal.
Perhaps the closest to the subject invention is ~T.S. patent no. 3,659,107, issued to Seele et al. on Apr~l 25, 1972, whlch describes a rad~oactlve fuel capsule, rlot a waste container, but whlch states that lt may be made of various refractory materials, includlng nic kel and alloys thereof .
Because of the presence of chromium in stainless steel and other com-ponents in the other container materials now in use, they are all more or less thermodynamically unstable in the geochemlcal environments of natural rock formations, and lt is accepted that they can become corroded and decompose within a few tens of years after burial, Accordingly, prlmary emphasis in lmmoblllzlng nuclear wastes is placed upon the insolubillty of the radioactive elernents ~n the solldlfled waste and on the lmpermeablllty and lon-exchange propertles of the rock medlum. However, whlle thls solution has been the best ava~lable, it ls far from completely satlsfactory and it has long been obvlous that, lf the Integrity of the metal container itself could be guaranteedfor perlods exceeding a mlllion years, the problems associated with safe storage of nuclear wastes would be substantlally reduced.
Objects of the Invention It is, therefore, a general object of the invention to pro-vide containers for radioactive nuclear waste materials which will obviate or minimize problems of the type previously described.;
It is a particular object of the invention to provide such containers which will maintain their ~ntegrity for periods ex-ceeding a milIlon years.
It is a further object o this invention to obtain this integrity by the use of alloys which, unlike container materials hitherto used, are thermo-dynamically stable in the geochemical environment of natural under~round rock systems, ,. , ~
1~ 39 Other objects and advan~ages of the present invention will become apparent from the following detailed description thereof.
Thus, in accordance with one aspect of the invention, there is provided a container for radioactive nuclear waste materials which are ultimately to be buried underground, said container being composed of nickel~iron a:Lloys such as those natural minerals produced under ~hermodynamically stable conditions within serpentinite-type rocks and possessirlg a composition in the range exhibited by the minerals awaruite and josephinite.
In accordance with another aspect of the invention there is provided a method of containing radioactive nuclear waste materials over extended periods o~ time, said method comprising the steps of:
.. ..
(a) encapsulating the waste materials in a container composed of nickel-iron alloys such as those natural minerals produced under thermodynamically stable conditions within serpentinite-type rocks and possessing a composition in the range exhibited by the minerals awaruite and josephinite;
(b) burying the container underground in an impervious, stable rock formation.
DETAILED DESCRIPTION
During the metamorphic alteration of ultramafic rocks ;
~ to form serpentine, native nickel-iron alloys are often pro-;~ duced under thermodynamically stable conditions. These alloys ~:
constitute the mineral awaruite and are composed mainly of ;
nickel (60 to 90 percent) and iron (10 to 40 percent), together with small amounts of cobalt and copper (less than 5 percent ~ ;
each). The most common composition corresponds to the formula Ni3Fe, which is that of an ordered stoichiometric phase. --` ~LV~ 43~
" ... ... ..
Awaruite has been produced at elevated temperatures, probably exceeding 300C, during serpentinization of periodotite. In some examples, serpentinization has been caused by circulating -sea water. In both cases, it can be demonstrated that occurrences of awaruite have survived for periods exceeding tens of millions of years.
Another natural alloy which is found in serpentinized periodotite in large lumps is josephinite, which has a chemical composition similar to awaruite. The origin of josephinite is unclear, but it can be demonstrated that this alloy has also survived in association with serpentine and periodotite for periods exceeding tens of millions of years.
Both awaruite and josephinite are thermodynamically `~
stable over wide ranges Eh, Ph, temperature, pressure, and in the presence o~ ground waters containing substantial amounts of chloride ions and other solutes in the natural geochemical environment. Moreover, these alloys have a high melting point, high mechanical strength, and can be caste, fabricated, and ~ ;
machined. Because of these properties, it has become apparent to us that -'': ' , , i -3a-,, ,. ' : : , i~ .
~ .
these alloys would make ideal containers for solid nuclear waste materials which are to be buried underground ln the natural geochemical environment.
This is the essence of our invention. Both minerals are known per se, and we of course do not claim to have discovered or lnvented the minerals as such. Similarly, our invention is not a new structural design for nuclear waste containers, nor ls lt limited to any particular waste container structure.
WHAT IS CLAIMED IS-
FIELD OF THE INVENTION
This invention relates to improved nuclear waste container materials possessing high corros:ion resistance when buried in natural rock formations. Integr:ity is obtained by the use of alloys which are thermodynamically stable in the geochemical environment of natural underground rock systems.
_ACKGROUND OF THE INVENTION -Modern nuclear reactors produce highly radioactive fission products and actinide elements which must be prevented from entering the biosphere over periods ranging from 10 to 1,000,000 years. The current policy and practice is to convert these high-level nuclear wastes to solid forms such as glasses or ceramic~, which are ~hen encapsulated in metal containers and buried underground in impervious, stable rock formations.
There are a great many patents directed to the structure of containers for nuclear wastes. Most contain only brief disclosures of the materials from which the containers are made. Stainless steël is named repeatedly as well as iron, steel~ lead, concrete, steel lined with copper, brass, zirconium alloy, cadmium, tantalum, tungsten, mercury, moly-bdenum, and sandwich ;
. ' ' .
,'~':.~, ' ~' ' .;' ',..
'': ~'`. ' ,' '. '."." .
-1- : '.' ~ ' ' ' .,:
8~435~
constructions employing various gels and flbers between layers of metal.
Perhaps the closest to the subject invention is ~T.S. patent no. 3,659,107, issued to Seele et al. on Apr~l 25, 1972, whlch describes a rad~oactlve fuel capsule, rlot a waste container, but whlch states that lt may be made of various refractory materials, includlng nic kel and alloys thereof .
Because of the presence of chromium in stainless steel and other com-ponents in the other container materials now in use, they are all more or less thermodynamically unstable in the geochemlcal environments of natural rock formations, and lt is accepted that they can become corroded and decompose within a few tens of years after burial, Accordingly, prlmary emphasis in lmmoblllzlng nuclear wastes is placed upon the insolubillty of the radioactive elernents ~n the solldlfled waste and on the lmpermeablllty and lon-exchange propertles of the rock medlum. However, whlle thls solution has been the best ava~lable, it ls far from completely satlsfactory and it has long been obvlous that, lf the Integrity of the metal container itself could be guaranteedfor perlods exceeding a mlllion years, the problems associated with safe storage of nuclear wastes would be substantlally reduced.
Objects of the Invention It is, therefore, a general object of the invention to pro-vide containers for radioactive nuclear waste materials which will obviate or minimize problems of the type previously described.;
It is a particular object of the invention to provide such containers which will maintain their ~ntegrity for periods ex-ceeding a milIlon years.
It is a further object o this invention to obtain this integrity by the use of alloys which, unlike container materials hitherto used, are thermo-dynamically stable in the geochemical environment of natural under~round rock systems, ,. , ~
1~ 39 Other objects and advan~ages of the present invention will become apparent from the following detailed description thereof.
Thus, in accordance with one aspect of the invention, there is provided a container for radioactive nuclear waste materials which are ultimately to be buried underground, said container being composed of nickel~iron a:Lloys such as those natural minerals produced under ~hermodynamically stable conditions within serpentinite-type rocks and possessirlg a composition in the range exhibited by the minerals awaruite and josephinite.
In accordance with another aspect of the invention there is provided a method of containing radioactive nuclear waste materials over extended periods o~ time, said method comprising the steps of:
.. ..
(a) encapsulating the waste materials in a container composed of nickel-iron alloys such as those natural minerals produced under thermodynamically stable conditions within serpentinite-type rocks and possessing a composition in the range exhibited by the minerals awaruite and josephinite;
(b) burying the container underground in an impervious, stable rock formation.
DETAILED DESCRIPTION
During the metamorphic alteration of ultramafic rocks ;
~ to form serpentine, native nickel-iron alloys are often pro-;~ duced under thermodynamically stable conditions. These alloys ~:
constitute the mineral awaruite and are composed mainly of ;
nickel (60 to 90 percent) and iron (10 to 40 percent), together with small amounts of cobalt and copper (less than 5 percent ~ ;
each). The most common composition corresponds to the formula Ni3Fe, which is that of an ordered stoichiometric phase. --` ~LV~ 43~
" ... ... ..
Awaruite has been produced at elevated temperatures, probably exceeding 300C, during serpentinization of periodotite. In some examples, serpentinization has been caused by circulating -sea water. In both cases, it can be demonstrated that occurrences of awaruite have survived for periods exceeding tens of millions of years.
Another natural alloy which is found in serpentinized periodotite in large lumps is josephinite, which has a chemical composition similar to awaruite. The origin of josephinite is unclear, but it can be demonstrated that this alloy has also survived in association with serpentine and periodotite for periods exceeding tens of millions of years.
Both awaruite and josephinite are thermodynamically `~
stable over wide ranges Eh, Ph, temperature, pressure, and in the presence o~ ground waters containing substantial amounts of chloride ions and other solutes in the natural geochemical environment. Moreover, these alloys have a high melting point, high mechanical strength, and can be caste, fabricated, and ~ ;
machined. Because of these properties, it has become apparent to us that -'': ' , , i -3a-,, ,. ' : : , i~ .
~ .
these alloys would make ideal containers for solid nuclear waste materials which are to be buried underground ln the natural geochemical environment.
This is the essence of our invention. Both minerals are known per se, and we of course do not claim to have discovered or lnvented the minerals as such. Similarly, our invention is not a new structural design for nuclear waste containers, nor ls lt limited to any particular waste container structure.
WHAT IS CLAIMED IS-
Claims (10)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A container for radioactive nuclear waste materials which are ultimately to be buried underground, said container being composed of nickel-iron alloys such as those natural minerals produced under thermodynamically stable conditions within serpentinite-type rocks and possessing a composition in the range exhibited by the minerals awaruite and josephinite.
2. A container as recited in claim 1 wherein said alloy is selected from the group consisting of awaruite and josephinite.
3. A container as recited in claim 2 wherein said alloy is awaruite.
4. A container as recited in claim 2 wherein said alloy is josephinite.
5. A container as recited in claim 1 wherein the nickel content of said alloy is in the range 60-90 percent and the iron content of said alloy is in the range 10-40 percent.
6. A container as recited in claim 5 wherein said alloy also contains up to 5 percent cobalt.
7. A container as recited in claim 6 wherein said alloy also contains up to 5 percent copper.
8. A container as recited in claim 5 wherein said alloy also contains up to 5 percent copper.
9. A container as recited in claim 1 wherein said alloy is composed of the stoichiometric alloy phase Ni3Fe.
10. A method of containing radioactive nuclear waste materials over extended periods of time, said method comprising the steps of (a) encapsulating the waste materials in a container composed of nickel-iron alloys such as those natural minerals produced under thermodynamically stable conditions within serpentinite-type rocks and possessing a composition in the range exhibited by the minerals awaruite and josephinite.
(b) burying the container underground in an impervious, stable rock formation.
(b) burying the container underground in an impervious, stable rock formation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA325,367A CA1088439A (en) | 1979-04-11 | 1979-04-11 | Container for radioactive nuclear waste materials |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA325,367A CA1088439A (en) | 1979-04-11 | 1979-04-11 | Container for radioactive nuclear waste materials |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1088439A true CA1088439A (en) | 1980-10-28 |
Family
ID=4113958
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA325,367A Expired CA1088439A (en) | 1979-04-11 | 1979-04-11 | Container for radioactive nuclear waste materials |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1088439A (en) |
-
1979
- 1979-04-11 CA CA325,367A patent/CA1088439A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |