CA2045809C - Transmutation treatment of radioactive wastes - Google Patents
Transmutation treatment of radioactive wastesInfo
- Publication number
- CA2045809C CA2045809C CA 2045809 CA2045809A CA2045809C CA 2045809 C CA2045809 C CA 2045809C CA 2045809 CA2045809 CA 2045809 CA 2045809 A CA2045809 A CA 2045809A CA 2045809 C CA2045809 C CA 2045809C
- Authority
- CA
- Canada
- Prior art keywords
- radioactive
- nuclides
- transmutation
- resonance
- nuclei
- 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 - Fee Related
Links
- 238000009377 nuclear transmutation Methods 0.000 title claims abstract description 28
- 239000002901 radioactive waste Substances 0.000 title claims abstract description 14
- 150000001875 compounds Chemical class 0.000 claims abstract description 21
- 238000006243 chemical reaction Methods 0.000 claims abstract description 18
- 230000002285 radioactive effect Effects 0.000 claims abstract description 18
- 238000000034 method Methods 0.000 claims abstract description 17
- 230000001131 transforming effect Effects 0.000 claims abstract description 5
- 230000005855 radiation Effects 0.000 description 6
- 239000002699 waste material Substances 0.000 description 5
- 230000008901 benefit Effects 0.000 description 4
- 230000004907 flux Effects 0.000 description 4
- 230000009466 transformation Effects 0.000 description 4
- 230000001133 acceleration Effects 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- XLYOFNOQVPJJNP-ZSJDYOACSA-N Heavy water Chemical compound [2H]O[2H] XLYOFNOQVPJJNP-ZSJDYOACSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 239000002927 high level radioactive waste Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910052695 Americium Inorganic materials 0.000 description 1
- 229910052685 Curium Inorganic materials 0.000 description 1
- 229910052781 Neptunium Inorganic materials 0.000 description 1
- 229910052778 Plutonium Inorganic materials 0.000 description 1
- 229910052770 Uranium Inorganic materials 0.000 description 1
- 229910052768 actinide Inorganic materials 0.000 description 1
- 150000001255 actinides Chemical class 0.000 description 1
- 230000001154 acute effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 239000002826 coolant Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000004992 fission Effects 0.000 description 1
- 239000010808 liquid waste Substances 0.000 description 1
- 239000003758 nuclear fuel Substances 0.000 description 1
- OYEHPCDNVJXUIW-UHFFFAOYSA-N plutonium atom Chemical compound [Pu] OYEHPCDNVJXUIW-UHFFFAOYSA-N 0.000 description 1
- 239000012857 radioactive material Substances 0.000 description 1
- 238000012958 reprocessing Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000011343 solid material Substances 0.000 description 1
- DNYWZCXLKNTFFI-UHFFFAOYSA-N uranium Chemical compound [U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U] DNYWZCXLKNTFFI-UHFFFAOYSA-N 0.000 description 1
- 238000004017 vitrification Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
- G21F9/00—Treating radioactively contaminated material; Decontamination arrangements therefor
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- High Energy & Nuclear Physics (AREA)
- Processing Of Solid Wastes (AREA)
- Physical Or Chemical Processes And Apparatus (AREA)
Abstract
A method of transmutation treatment of radioactive waste Radioactive nuclides to be treated contained in the radioactive wastes are accelerated to an energy level corresponding to a compound nucleus resonance level. The accelerated nuclides are then smashed or bombarded into a thermal neutron field which is under a magnetic field, to cause the compound nucleus resonance reaction to occur, thereby transforming the radioactive nuclides into those which are more stable or have shorter life.
Description
2 0 ~ ~ 8 O 9 TRANSMUTA~ION TREATMENT OF RADIOACTIVE WASTES
BACKGROUND OF THE INVENTION
The present invention relates to a method of quickly transmutating or reducing the level of radiations from radioactive wastes by transforming radioactive nuclides with long lifetime contained in radioactive wastes into those with shorter life or stable ones.
Contained in high-level radioactive wastes generated after reprocessing spent nuclear fuels from nuclear reactors are various kinds of long-lived nuclides, which include fission products (Cs, Sr, Tc, etc.), actinoids ~Np, Am, Cm, etc.) produced as a result of nuclear reactions and unrecovered uranium and plutonium.
The currently available method for final disposal of such high-level radioactive wastes is to seal them in vitrified solids under rigid control and store them in a controlled area until the radiation level decreases to allowable levels by the decaying process. However, the vitrification of radioactive wastes with long average lifetime requires many years of stringent supervision of the : :: ' :: : ::
stored wastes and as the amount of wastes increases, it will become~increasingly d1fficult to select and secure the storage site.
If it is possible to tFansiorm the long-lived ..
, 2~5~0~
radioactive nuclides into those with shorter life or stable ones, the period over which the stored radioactive waste materials must be supervised can be reduced and so also the need for finding storage sites, offering significant advantages in terms of safety and economy involved in the waste disposal process.
Among the transmutation processing of the radioactive material utilizing the nuclear transformation, the most common is considered to be one that radiates neutrons against radioactive nuclides. The radiated neutrons are absorbed in nuclei, transforming the nuclei into those with shorter life and more stable ones.
Possible candidate neutrons that can be utilized for the transmutation treatment include low-energy neutrons such as thermal neutrons obtained from the nuclear reactor.
The absorption of low-energy neutrons into nuclei occurs mainly during a radiative capture reaction l(n, ~) reaction]. This reaction shows an acute resonance, as can be seen from a graph of Figure 5 that shows the neutron radiatlve capture cross section for 99Tc. Such a resonance phenomenon can be explained by the formation of compound nuclei. Some of the capture cross sections at the resonance level have large values, and the greater the capture cross section, the more likely the capture reaction wilI occur.
Howe~er, the neutron energy from the nuclear reactor is continuously distributed and hence it is difficult to ~: , : ~ - . '~ " . ' : ' - . ' -. .
- .' '' -- ~'' " ' . :' 2 ~ Q 9 efficiently obtain a neutron flux of a particular energy that agrees with the resonance level of the nuclei.
SUMMARY OF THE INVENTION
An object of the present invention is therefore to provide a method which can trigger a compound nucleus resonance reaction even with thermal neutrons that do not have an energy equal to a particular resonance level, and thereby carry out the nuclear transformation of radioactive nuclides to efficiently perform the transmutation treatment on the radioactive wastes.
The inventors have come to an idea that instead of controlling the energy of neutrons to be radiated against nuclei, the nuclei are accelerated and bombarded into a neutron field to trigger the compound nucleus resonance reaction. That is, if the resonance level energy E of neutrons in a system where the accelerated neutrons are radiated against the fixed nuclei is to be produced by accelerating the nuclei with the neutrons fixed, the kinetic energy of the nuclei required to cause the compound nucleus ~: :
resonance reaction will be (M/m)E, where M is a mass of nuclei and m is a mass of neutrons.~ Thus, the compound nucleus resonance reaction can be made to initiate without controlling the neutron energy, only by giving the nuclei the klnetlc energy which is (M/m) times the resonance level energy~of the neutrons.
The transmutation treatment method for radioactive ~: ' , .. ' , ' ' . , . ' ' -' 2~8Q~
wastes of the present invention is based on the above-described principle. Thus, according to the present invention, radioactive nuclides to be treated contained in the radioactive wastes are accelerated to an energy level corresponding to a compound nucleus resonance level. The accelerated nuclides are then smashed or bombarded into a thermal neutron field which is under a magnetic field, to cause the compound nucleus resonance reaction to occur, thereby transforming the radioactive nuclides into those which are more stable or have shorter life.
In the present invention, by accelerating the radioactive nuclides to an energy equal to the compound nucleus resonance level and smashing them into the thermal neutron field, it is possible to cause the compound nucleus resonance reaction to occur between the accelerated nuclides and the thermal neutrons, even when the thermal neutrons do not have a resonance level energy. This method, therefore, can efficiently transform the long-lived radioactive nuclides into stable or short-lived nuclides.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic cross section showing the concept of a preferred embodiment of the transmutation treatment apparatus employed in the present invention;
Figure 2 is a schematic illustration showing the operation of the apparatus of Figure 1;
Figure 3 is a plan view of Figure 2;
~' :
8~
Figure 4 is a graph showing the relationship between the acceleration energy and the transmutation rate of 99Tc; and Figure 5 is a graph showing the neutron capture cross section of 99TC.
PREFERRED EMBODIMENTS OF THE INVENTION
Figure 1 schematically shows one example of radioactivity transmutation treatment apparatus that embodies the method of this invention. Around a reactor core 1 of a nuclear reactor such as a fast reactor is installed a moderator layer 2 consisting of heavy water.
The moderator layer 2 is further enclosed by a nuclear transmutation vessel 3. The core 1 and the nuclear transmutation vessel 3 are enclosed by a shielding material 4 to shield radiations. The core 1 is of course equipped with a cooling system 5 such as a coolant circulation system. The nuclear transmutation vessel 3 is under the influence of a magnetic field generated by an electromagnet 7 electrically connected to a power source 6 ~and is evacuated by a vacuum pump 8. In the nuclear transmutation ~: :
vessel~3~thermal neutrons emanating from the core 1 produce a thermal neutron field. The magnetic field applied to the nuclear transmutation vessel 3 accumulates the aocelerated nuclei thrown into the thermal neutron field. An a~ccelerator 9 accelerates radioactive nuclides to drive them to~the~nuclear t~ransmutation vessel 3. The accelerated nuclei are introduced through a leading pipe 10 into the , ~
. :. :: :
~ .
- : , , .
2 ~ 9 nuclear transmutation vessel 3 and discharged from a discharge pipe 11.
The operation of the transmutation treatment apparatus is explained by referring to Figures 2 and 3. High-level radioactive liquid waste are chemically treated to concentrate only the elements that are to be processed for transmutation. For example, 99Tc and 107Pd may be extracted as single-color solid materials and 129I as a stable compound. In the case of Tc, the nuclei are introduced into the ion source portion of the accelerator 9 where they are heated, evaporated and ionized by electrons. After this, the nuclei are sent to the acceleration portion of the accelerator 9 where they are accelerated to a specified energy level, and then introduced through the leading pipe 10 into the nuclear transmutation vessel 3. The accelerated nuclei introduced in the vessel 3, as shown in Figure 2, speed spirally through the thermal neutron field in the nuclear transmutation vessel 3 toward the discharge pipe 11.
During this spiral movement, the nuclei react efficiently with the thermal neutrons resulting in the compound nucleus resonance reaction. Then, the long-lived radioactive nuclide is transformed into a stable or short-lived nuclide before being discharged from the discharge pipe 11. The nuclides that have not reacted are separated and recovered by chemical treatment and resupplied to the accelerator 9 as shown by the broken line for further transmutation processing.
8~
The result of calculation is shown below for a case where the transmutation treatment method of this invention is applied to the nuclide 99TC. The nuclear transformation of 99Tc proceeds as follows.
99Tc ~half-life: 2.1 X 105 years) Neutron absorption Tc (half-life: 15.8 seconds) ~ ~ decay 100RU (stable) The parameters used in the calculation are as follows.
Thermal neutron flux obtained by the nuclear reactor:
1 o1 5cm-2sec-1 Thermal neutron temperature: 300~K
Resonance parameters of 99Tc:
Neutron resonance energy in the center-of-mass system: 5.6 eV
Neutron decay width rn: 5.00 meV
7 decay width rr: 134~0 meV
Resonance level width r 139.0 meV
Nucleus spin before reaction I: 4.5 Compound nucleus spin J: 4.0 The relationship between the acceleration energy and the transformation rate of 99Tc in the thermal neutron field is shown in Figure 4F As can be seen from this graph, the peak ~value o~ the transmutatior. rate of 99Tc is 1.4 x 10~5sec~1.
: : ~
For comparison, let us~consider a case where the thermal neutron capture reaction is performed with the nuclei fixed.
: ' ' .
,' ' . . :
2Q~8Q~
Since the thermal neutron capture reaction cross section of 99Tc is 20 barn, the transmutation rate is given by 20 x 10-24 * 1015 = 2 x 10-8 sec~1 This means that the transmutation rate is 700 times higher for the method of this invention that uses nuclei accelerated to the resonance level.
If this is interpreted in terms of half-life, 99Tc has the half-life of 2.1 x 105 years in the natural environment.
That is, when left in the natural environment, the 99Tc takes 2.1 x 105 years before the intensity of the radioactivity is reduced to one-half. On the other hand, when the nuclide is placed in the thermal neutron field with a flux of 1015cm~2sec~1, the radiation level decreases to one-half in 1.1 years. Further, when 99Tc is accelerated to the compound nucleus resonance energy and smashed into the thermal neutron field as in this invention, the radiation level decreases to one-hallf in 13.8 hours.
As mentioned above, this invention quickens the transmutation rate and the resulting advantages may be summarized as follows.
When it is desired to reduce the radiation level of 99Tc to one thousandth and if the nuclide is simply placed in the thermal neutron field with the flux of 1 o1 5cm~2sec~1l it will;take 11 years. The method of this invention, however, takes only 5.75 days. Therefore, in the design of actual transmutation treatment apparatus, this high transmutation rate is advantageous in light of durability of the apparatus ' :, ~' ' .
.:
, " .
2~8~
As described in the foregoing, the method of this invention accelerates the nuclei to an energy level corresponding to the compound nucleus resonance level corresponding to the compound nucleus resonance level and drives them into the thermal neutron field. This allows the compound nucleus resonance reaction to occur even when such a neutron source as nuclear reactors is used, in which it is difficult to obtain neutrons of a specific energy. This invention therefore can tansform long-lived radioactive nuclides into stable or short-lived nuclides with high efficiency.
As a result, the period over which the radioactive wastes are stored and the area of the storage site can be reduced, offering great advantages in terms of safety and economy involved in the waste disposal.
Another advantage of this invention is that since each nuclide has its own unique compound nucleus resonance energy, it is possible to selectively transmutate a part1cular nuclide at a high rate even when other nuclides coexist. Hence, there is no need to separate the isotopes and the only process required before this transmutation treatment is the chemical separation process.
~: :
: . .:
g ,.- ,- , . : . ~ ": . .
,~ , . . .
BACKGROUND OF THE INVENTION
The present invention relates to a method of quickly transmutating or reducing the level of radiations from radioactive wastes by transforming radioactive nuclides with long lifetime contained in radioactive wastes into those with shorter life or stable ones.
Contained in high-level radioactive wastes generated after reprocessing spent nuclear fuels from nuclear reactors are various kinds of long-lived nuclides, which include fission products (Cs, Sr, Tc, etc.), actinoids ~Np, Am, Cm, etc.) produced as a result of nuclear reactions and unrecovered uranium and plutonium.
The currently available method for final disposal of such high-level radioactive wastes is to seal them in vitrified solids under rigid control and store them in a controlled area until the radiation level decreases to allowable levels by the decaying process. However, the vitrification of radioactive wastes with long average lifetime requires many years of stringent supervision of the : :: ' :: : ::
stored wastes and as the amount of wastes increases, it will become~increasingly d1fficult to select and secure the storage site.
If it is possible to tFansiorm the long-lived ..
, 2~5~0~
radioactive nuclides into those with shorter life or stable ones, the period over which the stored radioactive waste materials must be supervised can be reduced and so also the need for finding storage sites, offering significant advantages in terms of safety and economy involved in the waste disposal process.
Among the transmutation processing of the radioactive material utilizing the nuclear transformation, the most common is considered to be one that radiates neutrons against radioactive nuclides. The radiated neutrons are absorbed in nuclei, transforming the nuclei into those with shorter life and more stable ones.
Possible candidate neutrons that can be utilized for the transmutation treatment include low-energy neutrons such as thermal neutrons obtained from the nuclear reactor.
The absorption of low-energy neutrons into nuclei occurs mainly during a radiative capture reaction l(n, ~) reaction]. This reaction shows an acute resonance, as can be seen from a graph of Figure 5 that shows the neutron radiatlve capture cross section for 99Tc. Such a resonance phenomenon can be explained by the formation of compound nuclei. Some of the capture cross sections at the resonance level have large values, and the greater the capture cross section, the more likely the capture reaction wilI occur.
Howe~er, the neutron energy from the nuclear reactor is continuously distributed and hence it is difficult to ~: , : ~ - . '~ " . ' : ' - . ' -. .
- .' '' -- ~'' " ' . :' 2 ~ Q 9 efficiently obtain a neutron flux of a particular energy that agrees with the resonance level of the nuclei.
SUMMARY OF THE INVENTION
An object of the present invention is therefore to provide a method which can trigger a compound nucleus resonance reaction even with thermal neutrons that do not have an energy equal to a particular resonance level, and thereby carry out the nuclear transformation of radioactive nuclides to efficiently perform the transmutation treatment on the radioactive wastes.
The inventors have come to an idea that instead of controlling the energy of neutrons to be radiated against nuclei, the nuclei are accelerated and bombarded into a neutron field to trigger the compound nucleus resonance reaction. That is, if the resonance level energy E of neutrons in a system where the accelerated neutrons are radiated against the fixed nuclei is to be produced by accelerating the nuclei with the neutrons fixed, the kinetic energy of the nuclei required to cause the compound nucleus ~: :
resonance reaction will be (M/m)E, where M is a mass of nuclei and m is a mass of neutrons.~ Thus, the compound nucleus resonance reaction can be made to initiate without controlling the neutron energy, only by giving the nuclei the klnetlc energy which is (M/m) times the resonance level energy~of the neutrons.
The transmutation treatment method for radioactive ~: ' , .. ' , ' ' . , . ' ' -' 2~8Q~
wastes of the present invention is based on the above-described principle. Thus, according to the present invention, radioactive nuclides to be treated contained in the radioactive wastes are accelerated to an energy level corresponding to a compound nucleus resonance level. The accelerated nuclides are then smashed or bombarded into a thermal neutron field which is under a magnetic field, to cause the compound nucleus resonance reaction to occur, thereby transforming the radioactive nuclides into those which are more stable or have shorter life.
In the present invention, by accelerating the radioactive nuclides to an energy equal to the compound nucleus resonance level and smashing them into the thermal neutron field, it is possible to cause the compound nucleus resonance reaction to occur between the accelerated nuclides and the thermal neutrons, even when the thermal neutrons do not have a resonance level energy. This method, therefore, can efficiently transform the long-lived radioactive nuclides into stable or short-lived nuclides.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic cross section showing the concept of a preferred embodiment of the transmutation treatment apparatus employed in the present invention;
Figure 2 is a schematic illustration showing the operation of the apparatus of Figure 1;
Figure 3 is a plan view of Figure 2;
~' :
8~
Figure 4 is a graph showing the relationship between the acceleration energy and the transmutation rate of 99Tc; and Figure 5 is a graph showing the neutron capture cross section of 99TC.
PREFERRED EMBODIMENTS OF THE INVENTION
Figure 1 schematically shows one example of radioactivity transmutation treatment apparatus that embodies the method of this invention. Around a reactor core 1 of a nuclear reactor such as a fast reactor is installed a moderator layer 2 consisting of heavy water.
The moderator layer 2 is further enclosed by a nuclear transmutation vessel 3. The core 1 and the nuclear transmutation vessel 3 are enclosed by a shielding material 4 to shield radiations. The core 1 is of course equipped with a cooling system 5 such as a coolant circulation system. The nuclear transmutation vessel 3 is under the influence of a magnetic field generated by an electromagnet 7 electrically connected to a power source 6 ~and is evacuated by a vacuum pump 8. In the nuclear transmutation ~: :
vessel~3~thermal neutrons emanating from the core 1 produce a thermal neutron field. The magnetic field applied to the nuclear transmutation vessel 3 accumulates the aocelerated nuclei thrown into the thermal neutron field. An a~ccelerator 9 accelerates radioactive nuclides to drive them to~the~nuclear t~ransmutation vessel 3. The accelerated nuclei are introduced through a leading pipe 10 into the , ~
. :. :: :
~ .
- : , , .
2 ~ 9 nuclear transmutation vessel 3 and discharged from a discharge pipe 11.
The operation of the transmutation treatment apparatus is explained by referring to Figures 2 and 3. High-level radioactive liquid waste are chemically treated to concentrate only the elements that are to be processed for transmutation. For example, 99Tc and 107Pd may be extracted as single-color solid materials and 129I as a stable compound. In the case of Tc, the nuclei are introduced into the ion source portion of the accelerator 9 where they are heated, evaporated and ionized by electrons. After this, the nuclei are sent to the acceleration portion of the accelerator 9 where they are accelerated to a specified energy level, and then introduced through the leading pipe 10 into the nuclear transmutation vessel 3. The accelerated nuclei introduced in the vessel 3, as shown in Figure 2, speed spirally through the thermal neutron field in the nuclear transmutation vessel 3 toward the discharge pipe 11.
During this spiral movement, the nuclei react efficiently with the thermal neutrons resulting in the compound nucleus resonance reaction. Then, the long-lived radioactive nuclide is transformed into a stable or short-lived nuclide before being discharged from the discharge pipe 11. The nuclides that have not reacted are separated and recovered by chemical treatment and resupplied to the accelerator 9 as shown by the broken line for further transmutation processing.
8~
The result of calculation is shown below for a case where the transmutation treatment method of this invention is applied to the nuclide 99TC. The nuclear transformation of 99Tc proceeds as follows.
99Tc ~half-life: 2.1 X 105 years) Neutron absorption Tc (half-life: 15.8 seconds) ~ ~ decay 100RU (stable) The parameters used in the calculation are as follows.
Thermal neutron flux obtained by the nuclear reactor:
1 o1 5cm-2sec-1 Thermal neutron temperature: 300~K
Resonance parameters of 99Tc:
Neutron resonance energy in the center-of-mass system: 5.6 eV
Neutron decay width rn: 5.00 meV
7 decay width rr: 134~0 meV
Resonance level width r 139.0 meV
Nucleus spin before reaction I: 4.5 Compound nucleus spin J: 4.0 The relationship between the acceleration energy and the transformation rate of 99Tc in the thermal neutron field is shown in Figure 4F As can be seen from this graph, the peak ~value o~ the transmutatior. rate of 99Tc is 1.4 x 10~5sec~1.
: : ~
For comparison, let us~consider a case where the thermal neutron capture reaction is performed with the nuclei fixed.
: ' ' .
,' ' . . :
2Q~8Q~
Since the thermal neutron capture reaction cross section of 99Tc is 20 barn, the transmutation rate is given by 20 x 10-24 * 1015 = 2 x 10-8 sec~1 This means that the transmutation rate is 700 times higher for the method of this invention that uses nuclei accelerated to the resonance level.
If this is interpreted in terms of half-life, 99Tc has the half-life of 2.1 x 105 years in the natural environment.
That is, when left in the natural environment, the 99Tc takes 2.1 x 105 years before the intensity of the radioactivity is reduced to one-half. On the other hand, when the nuclide is placed in the thermal neutron field with a flux of 1015cm~2sec~1, the radiation level decreases to one-half in 1.1 years. Further, when 99Tc is accelerated to the compound nucleus resonance energy and smashed into the thermal neutron field as in this invention, the radiation level decreases to one-hallf in 13.8 hours.
As mentioned above, this invention quickens the transmutation rate and the resulting advantages may be summarized as follows.
When it is desired to reduce the radiation level of 99Tc to one thousandth and if the nuclide is simply placed in the thermal neutron field with the flux of 1 o1 5cm~2sec~1l it will;take 11 years. The method of this invention, however, takes only 5.75 days. Therefore, in the design of actual transmutation treatment apparatus, this high transmutation rate is advantageous in light of durability of the apparatus ' :, ~' ' .
.:
, " .
2~8~
As described in the foregoing, the method of this invention accelerates the nuclei to an energy level corresponding to the compound nucleus resonance level corresponding to the compound nucleus resonance level and drives them into the thermal neutron field. This allows the compound nucleus resonance reaction to occur even when such a neutron source as nuclear reactors is used, in which it is difficult to obtain neutrons of a specific energy. This invention therefore can tansform long-lived radioactive nuclides into stable or short-lived nuclides with high efficiency.
As a result, the period over which the radioactive wastes are stored and the area of the storage site can be reduced, offering great advantages in terms of safety and economy involved in the waste disposal.
Another advantage of this invention is that since each nuclide has its own unique compound nucleus resonance energy, it is possible to selectively transmutate a part1cular nuclide at a high rate even when other nuclides coexist. Hence, there is no need to separate the isotopes and the only process required before this transmutation treatment is the chemical separation process.
~: :
: . .:
g ,.- ,- , . : . ~ ": . .
,~ , . . .
Claims (3)
1. A method of transmutation treatment of radioactive wastes comprsing the steps of:
accelerating radioactive nuclides to be treated contained in the radioactive wastes to an energy level corresponding to a compound nucleus resonance level; and samshing the accelerated nuclides into a thermal neutron field which is under a magnetic field, to cause the compound nucleus resonance reaction to occur;
thereby transforming the radioactive nuclides into those which are more stable or have shorter life.
accelerating radioactive nuclides to be treated contained in the radioactive wastes to an energy level corresponding to a compound nucleus resonance level; and samshing the accelerated nuclides into a thermal neutron field which is under a magnetic field, to cause the compound nucleus resonance reaction to occur;
thereby transforming the radioactive nuclides into those which are more stable or have shorter life.
2. The method according to claim 1, wherein the thermal neutron field is formed around a nuclear reactor and thermal neutrons are emanated from the nuclear reactor.
3. The method according to claim 1, wherein the radioactive nuclides to be treated are chemically extracted and separated from the radioactive wastes.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2-186390 | 1990-07-13 | ||
| JP18639090A JPH073474B2 (en) | 1990-07-13 | 1990-07-13 | Radioactive waste extinction treatment method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2045809A1 CA2045809A1 (en) | 1992-01-14 |
| CA2045809C true CA2045809C (en) | 1998-05-05 |
Family
ID=16187559
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2045809 Expired - Fee Related CA2045809C (en) | 1990-07-13 | 1991-06-27 | Transmutation treatment of radioactive wastes |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPH073474B2 (en) |
| CA (1) | CA2045809C (en) |
| DE (1) | DE4123145C2 (en) |
| FR (1) | FR2665570B1 (en) |
| GB (1) | GB2246467B (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2130206C1 (en) * | 1992-02-19 | 1999-05-10 | Открытое Акционерное Общество Научно-Исследовательский Институт Стали | Resonance-neutron fission chain reaction process |
| RU2003191C1 (en) * | 1993-01-18 | 1993-11-15 | Игорь Петрович Еремеев | Method of transmutation of isotopes |
| DE4410587C1 (en) * | 1994-03-26 | 1995-06-08 | Schwerionenforsch Gmbh | Measurement of transmutation cross=section of long life actinide(s) |
| RU2156001C1 (en) * | 1999-07-02 | 2000-09-10 | Тараторин Борис Иванович | Radioactive waste processing technique |
| US6738446B2 (en) * | 2000-02-24 | 2004-05-18 | General Atomics | System and method for radioactive waste destruction |
| RU2169405C1 (en) * | 2000-03-30 | 2001-06-20 | Закрытое акционерное общество "НЭК-Элтранс" | Method for transmutation of long-living radioactive isotopes into short-living or stable ones |
| RU2200353C1 (en) * | 2001-05-28 | 2003-03-10 | Мешковский Игорь Касьянович | Method for decontaminating radioactive wastes |
| US7423359B2 (en) * | 2004-06-18 | 2008-09-09 | Moog Inc. | Fluid-dispensing reservoir for large-diameter slip rings |
| RU2415486C1 (en) * | 2009-12-29 | 2011-03-27 | Федеральное государственное учреждение Российский научный центр "Курчатовский институт" | Method of element transmutation |
| US9728280B2 (en) | 2013-05-17 | 2017-08-08 | Martin A. Stuart | Dielectric wall accelerator utilizing diamond or diamond like carbon |
| CN106340336B (en) * | 2016-09-23 | 2018-03-13 | 中国科学院合肥物质科学研究院 | A kind of system using isotope neutron source transmuting nuke rubbish |
| WO2020026173A1 (en) * | 2018-08-02 | 2020-02-06 | Lenr-Cities Suisse Sàrl | A method and system for generating radioactive isotopes for medical applications |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE553519A (en) * | 1956-01-27 | 1900-01-01 | ||
| US3269915A (en) * | 1963-07-05 | 1966-08-30 | Neutron Products Inc | Neutron irradiation process for producing radioisotopes wherein target isotope is shielded from thermal neutrons |
| DE2249429A1 (en) * | 1972-10-09 | 1974-04-18 | Kernforschung Gmbh Ges Fuer | Fuel element fission product decay - by further irradiation in reactor core |
| US4309249A (en) * | 1979-10-04 | 1982-01-05 | The United States Of America As Represented By The United States Department Of Energy | Neutron source, linear-accelerator fuel enricher and regenerator and associated methods |
| AU539393B2 (en) * | 1979-12-05 | 1984-09-27 | Perm Inc. | Treating nuclear waste |
| WO1985004752A1 (en) * | 1984-04-09 | 1985-10-24 | Gerrit Berdinus Engelen | Method for systematic transformation of nuclides |
| FR2565397B1 (en) * | 1984-06-05 | 1986-08-22 | Commissariat Energie Atomique | DEVICE FOR CONDITIONING RADIOACTIVE WASTE CONSTITUTED BY ACTINIDS WITH MEDIUM AND / OR LONG PERIOD |
| DE3615518A1 (en) * | 1986-05-07 | 1987-11-12 | Pratzel Helmut Priv Doz Dr Dr | Method for decontaminating radioactively contaminated objects |
| JPH0638119B2 (en) * | 1989-03-02 | 1994-05-18 | 動力炉・核燃料開発事業団 | Radioactive waste extinction processing device and extinction processing method |
-
1990
- 1990-07-13 JP JP18639090A patent/JPH073474B2/en not_active Expired - Fee Related
-
1991
- 1991-06-27 CA CA 2045809 patent/CA2045809C/en not_active Expired - Fee Related
- 1991-07-04 FR FR9108362A patent/FR2665570B1/en not_active Expired - Fee Related
- 1991-07-11 GB GB9115002A patent/GB2246467B/en not_active Expired - Fee Related
- 1991-07-12 DE DE19914123145 patent/DE4123145C2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH073474B2 (en) | 1995-01-18 |
| GB2246467A (en) | 1992-01-29 |
| FR2665570B1 (en) | 1994-08-05 |
| JPH0472598A (en) | 1992-03-06 |
| GB9115002D0 (en) | 1991-08-28 |
| DE4123145C2 (en) | 2003-01-30 |
| CA2045809A1 (en) | 1992-01-14 |
| FR2665570A1 (en) | 1992-02-07 |
| DE4123145A1 (en) | 1992-02-06 |
| GB2246467B (en) | 1994-05-11 |
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| Date | Code | Title | Description |
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| EEER | Examination request | ||
| MKLA | Lapsed |