JPS63158120A - Isotope separation and its device - Google Patents

Abstract

PURPOSE:To improve the efficiency of separation of isotope and thereby obtain a product with high purity by neutralizing impurity ions in a prestage in which a vapor stream is conducted to an optical reaction part, and preventing the impurity ions from being adsorbed into a recovery electrode. CONSTITUTION:Impurity ions contained in a vapor stream 5 generated by thermal and collision ionizations are neutralized in advance by thermal electrons released from a thermal element 15 in a prestage in which a vapor stream 5 is conducted to an optical reaction part 8. As a result, the ions adsorbed by a recovery electrode 12 formed with anodes 6 and cathodes 7 arranged alternately become solely specific ionized isotopes which are optically ionized by a laser beam 9 projected by a laser beam oscillator 13. Consequently, the possibility that the separation efficiency of isotopes may be reduced, or that the purity of a product be deteriorated by the adsorption of impurity ions entrained into the recovery electrode 12, are minimized, contrary to what they were before. Thus a product with high purity can be obtained.

Description

Detailed Description of the Invention (Objective of the Invention) (Industrial Application Field) The present invention relates to a method and apparatus for separating a specific isotope from a mixture containing a plurality of isotopes, and in particular, to a method and apparatus for separating a specific isotope from a mixture containing a plurality of isotopes, and in particular, to reduce the effects of impurity ions. The present invention relates to an isotope separation method and separation device that improve the separation coefficient.

(Prior technology) Uranium fuel used in nuclear fuel for nuclear reactors is loaded into a nuclear reactor after separating and enriching the specific uranium that causes a nuclear reaction from a mixture of uranium isotopes and adjusting it to a predetermined concentration. be done.

Naturally occurring uranium contains approximately 0.7% uranium, which is made up of light molecules with a mass number of 235 (hereinafter abbreviated as U-235), and the remainder is mostly uranium (hereinafter referred to as U-235), which is made up of heavy molecules with a mass number of 238. -238). Of these, only U-235, which causes a nuclear reaction, is separated from the natural uranium or spent fuel, and usually 2 to 3
It is used as nuclear reactor fuel after being enriched to about 50%.

Conventionally, uranium enrichment methods for separating U-235 from a mixture containing isotopes such as U-235 and U-238 and increasing it to a predetermined concentration level include gas diffusion, centrifugation,
There are laser methods, etc., and each method performs separation and concentration operations using differences in the chemical properties or masses of isotopes.

Among the above separation methods, an isotope separation device using a laser is a separation method that is particularly promising in terms of separation efficiency. This separation method is described, for example, in JP-A-5-4-1268.
As disclosed in Publication No. 95, only the target isotope, for example, U-235, is produced by irradiating the vapor of an isotope mixture with a laser beam set at a resonance ionization wavelength that excites the nucleus of a specific isotope. is selectively ionized, an electric field is applied perpendicularly to the vapor flow containing this ionized isotope, and this electric field causes a specific ionized LJ to be ionized.
-235 is deflected in a predetermined direction and separated to enrich uranium.

Next, a conventional example of an isotope separation method and apparatus using laser light will be described with reference to FIGS. 6 and 7.

FIG. 6 is a perspective view showing the configuration of an isotope separation device using a laser beam used in the uranium enrichment process. The following will explain the separation operation of uranium isotopes as an example.

Metal uranium 1, such as natural uranium or waste uranium produced as a by-product in the enrichment process, is housed in an evaporation crucible 2 having excellent thermochemical resistance. Next, the electron beam 4 emitted from the linear electron gun 3 is deflected by an external magnetic field coil (not shown) and irradiated onto the metal uranium 1 in the evaporation crucible 2. Metallic uranium 1 irradiated by electron beam 4 has a mass of 2,500 ~
It is heated to about 2700X and evaporates, forming a vapor stream 5. The composition of the vapor stream 5 is, for example, when natural uranium is used as the metal uranium 1, the weight ratio is 0.7% U-235 and 99.3% U-238.

On the other hand, above the evaporation crucible 2, band-shaped positive electrodes 6 and negative electrodes 7 are arranged alternately, and a photoreaction part 8 is provided between the electrodes, and the photoreaction part 8 is extended in the longitudinal direction. U-2
Laser light 9 that selectively excites and ionizes only 35 is incident, and photoreacts with the vapor flow. Laser light 90 wavelength is tJ
-235 resonance ionization wavelength, and the photoreactive part 8
Only U-235 atoms contained in the vapor flow 5 introduced into the laser beam 9 resonate with the laser beam 9, and are selectively ionized with a certain probability to become ionized isotopes.

The ionized Ll-235 isotope is adsorbed and collected on the surface of the negative electrode 70, which serves as a collection electrode, by an electric field formed by applying a voltage between the Fil pole 6 and the negative electrode 7. On the other hand, U-23 that passed through the photoreaction part 8 without being ionized
The mixed vapor flow of 5 and U-238 is suctioned and collected by a vapor recovery plate 10 disposed on the outer edge side of the photoreaction section 8. The recovered vapor particles are returned to the M invention crucible 2 by a separate means.

Here, an isotope separation scheme using a photoionization reaction will be explained below using an atomic method as an example. FIG. 8 illustrates the energy unit of a uranium atom in a photoionization reaction. Ground level E. Two isotopic atoms A and B in
Of these, the process of selectively ionizing isotope atoms B for the purpose of recovery will be explained.

In these two types of isotopic atoms, the first-stage excitation rates E1a and E1° take different values due to the difference in the nuclear mass and nuclear spin of the atomic nucleus. That is, it has an isotope shift. Focusing on the difference, the first-stage excitation rate E, b of the isotope atom B is
A laser beam 9a set to a wavelength tuned to is irradiated to selectively excite only the isotope atom B. Next, the isotope atoms B are irradiated with the ionizing laser beam 9b in order to make a transition from the first stage excitation level E1b to the ionization level E.

Only the isotope atom B can be selectively ionized through the above two-step process. The laser beam 9 illustrated in FIGS. 6 and 7 is the excitation laser beam 9a described above.
This is a combination of the ionizing light 9b and the ionizing light 9b.

(Problems to be Solved by the Invention) According to the conventional isotope separation method and apparatus, as a pretreatment for separating uranium isotopes, metallic uranium is irradiated with a powerful electron beam and melted at high temperature. Since it has a step of evaporating and generating a vapor stream, the generated vapor stream has
Contains various impurity ions generated under high temperature conditions.

In other words, the impurity ions include collision ionized ions of Ll-238 generated by the collision between the electron beam and the vapor flow, and the contact of the vapor flow with the molten metal surface in the evaporation crucible heated to a high temperature of about 2700°C. There are thermoionized ions of U-238 and other metals generated by this process.

These impurity ions accompany the U-235' ions and get mixed into the cathode, which is the recovery electrode, and are sucked out, so the separation coefficient of U-235, which is originally intended for separation and recovery, decreases.
The degree of concentration also decreases. Therefore, there is a problem that the purity and quality of the recovered uranium deteriorates, which is a major obstacle to the use of this type of isotope separation method and apparatus.

Therefore, when adopting this type of isotope separation method and apparatus, it is especially necessary to completely separate various impurity ions generated near the evaporation crucible from photoionized ions generated in the photoreaction part. be done.

As part of this effort, it is currently being considered to electromagnetically separate and remove ionized ions of various impurities by applying a separate electric or magnetic field to the vapor flow before it is introduced into the photoreaction section. There is.

However, when using a steam flow with a high ionization rate, the effect of removing ionized ions by the electromagnetic field is still insufficient, and in addition, certain isotopes that are selectively photoionized in the photoreaction region In many cases, atomic ions are removed along with other impurities, and there remains room for further improvement in order to promote effective utilization of the vapor flow.

In addition, subjecting the vapor flow to an excessive electromagnetic field brings about the Stark effect and Zeeman effect, which leads to the splitting of the first stage excitation potential E1b illustrated in Fig. 8, and the specific isotope atoms characterized by recovery. There is also the risk of reducing the excitation rate of B. In other words, the opposite effect of reducing the number of ionized isotopes generated by photoionization and reducing the amount of separation and recovery is also expected.

The present invention was devised to solve the above-mentioned problems, and it eliminates impurity ions such as thermally ionized ions and electron impact ionized ions contained in the vapor flow before the vapor flow is introduced into the photoreaction section. An isotope separation method and method based on which isotope separation efficiency is increased by electrically neutralizing in advance and preventing impurity ions from being collected by a collection electrode, and a product with excellent purity quality can be obtained. The purpose is to provide equipment.

[Structure of the invention]

(Means for solving the problem) The isotope separation method according to the first invention of the present application heats and evaporates a substance containing multiple types of isotopes to generate a vapor flow, and the vapor flow is directed to a photoreaction part. In the vapor flow path leading to the vapor flow path, thermionic electrons are brought into contact with the vapor flow in advance to neutralize the charge of impurity cations contained in the vapor flow, and then the vapor flow consisting of neutral atoms is introduced into the photoreaction part, and the introduced vapor is Ionized isotopes are generated by irradiating the vapor stream with laser light that selectively excites and ionizes specific isotopes contained in the stream.
The present invention is characterized in that a specific isotope is separated and recovered by deflecting the ionized isotope in a predetermined direction of the recovery electrode by applying an electric field to a recovery electrode in which l electrodes and negative electrodes are arranged alternately.

Further, the isotope separation device according to the second invention of the present application includes a steam generation device that heats and evaporates substances containing multiple types of isotopes to generate a vapor flow, and positive electrodes and negative electrodes that are arranged side by side alternately. A recovery electrode with a photoreaction area formed between these electrodes, a heating element provided in a vapor flow path leading from the vapor generation device to the photoreaction area, and a vapor flow flowing into the photoreaction area of the positive electrode. a laser beam oscillation device that selectively ionizes a specific isotope by irradiating the laser beam with a laser beam; It is characterized by being set.

(Function) According to the present invention, a heating element is provided in the vapor flow path leading from the evaporation crucible to the photoreaction section, and this heating element generates heat when energized to form a thermionic swarm in the vapor path. When a vapor flow containing impurity ions comes into contact with this thermionic swarm, the impurity ions and thermionic electrons combine, the charge of the ions is neutralized, and the impurity ions become electrically neutral atoms or molecules. That is, the vapor flow introduced into the photoreaction section is neutralized by thermionic electrons emitted from the heating element, and the ionization rate becomes an extremely low value.

Therefore, the ions that are adsorbed to the recovery electrode by the electric field method are only specific ionized isotopes that have been selectively photoionized by the laser beam.

That is, according to the present invention, since impurity ions are neutralized before the vapor flow is introduced into the photoreaction section, the impurity ions are prevented from being adsorbed on the collection electrode, and the isotope separation efficiency is improved. It is possible to obtain products with improved purity and quality.

Further, in the treatment operation for reducing the influence of impurity ions, since no electric field or magnetic field is applied, splitting of specific isotope energy units due to the Stark effect or Zeeman effect is less likely to occur. Therefore, there is little reduction in the excitation rate of the isotope to be recovered, and high separation efficiency is maintained.

(Example) Next, examples of the method and apparatus of the present invention will be described with reference to the drawings, taking as an example an operation for separating uranium isotopes in a uranium enrichment process.

FIG. 1 is a sectional view schematically showing an embodiment of an isotope separation apparatus for carrying out the method of the present invention.

Note that the same components as those in the conventional example shown in FIGS. 6 and 7 are given the same reference numerals.

The isotope separation apparatus according to the present invention includes an evaporation crucible 2 containing uranium metal 1, and irradiates the uranium metal 1 with an electron beam 4 generated from a linear electron gun 3 to heat and evaporate the uranium metal 1, thereby generating a vapor flow 5. It has a steam generation device 11 that performs.

Above the steam generator 11, a positive electrode 6 and a negative electrode 7 are provided.
Recovery electrodes 12 are provided, which are formed by alternately arranging and juxtaposing. Further, a photoreaction section 8 is formed between each of the anode and cathode electrodes 6 and 7, and a laser beam oscillation device 13 for irradiating the vapor flow 5 flowing into the photoreaction section 8 with a laser beam 9 is provided. Further, a steam flow passage 14 through which the steam flow 5 flows in a fan shape is formed between the steam generation device 11 and the recovery electrode 12, and a heating element 1 supplies thermoelectrons to the steam flow 5 passing through the steam flow passage 14.
5 is provided.

For example, as shown in FIG. 2, the heating element 15 is constructed by winding a linear heater in the same plane while maintaining an insulating distance, and is disposed perpendicular to the flow of the steam flow 5.

Although the heating element is not shown in the drawings, it may be configured as a planar heater with steam through-holes formed therein.

As shown in FIG. 1, the heating element 15 is energized by a heater power source 16 and generates heat. Thermionic electrons are emitted from the surface of the linear heater that generates heat. Thermionic electrons form a thermionic swarm in the gap between the linear heaters. When the vapor flow 5 passes through the void, the impurity ions react with and combine with thermionic electrons. The electric charge of the impurity ions is neutralized by thermionic electrons, and the vapor flow 5 that has passed through the heating element 15 becomes neutral vapor containing no impurity ions.

Here, the amount of impurity ions generated and the thermoelectric indicator generated from the heating element 15 are calculated according to specific numerical values, and the effect of neutralizing the impurity ions is evaluated.

Free electrons present in the heating element 15 usually have a low potential corresponding to the Fermi level.

Further, the potential energy of the Fermi level is lower than the outside world by the work function φ, and free electrons having high energy at a specific high temperature are emitted from the surface of the object to the outside world.

If we calculate the thermionic current density J emitted from the object surface assuming that the energy of free electrons in the object follows Fermi-Dirac statistics, then (1) for the temperature T of the object surface, that is, the surface temperature of the heating element 15. It is honored at a ceremony.

·········(Month Here, the elementary quantity of electricity e is 1.602x10 C.

Electron quality 111m 9.107X 10-” K!J,
Let the y constant be 6.624X10 J-3 and the Portzmann constant k be 1.380X10 J/.

In addition, the work function φ in the case of a normal metal is about 1ev. For example, if a high melting point material and a highly corrosion resistant material are used as the heating element 15 and the operating temperature T is 2000'', the thermionic current density J is As shown in equation (2),

'J=4.9X10 (A/condition)...
(2) Next, the number Φ8 of electrons emitted from the surface of the heating element 15 per unit time is calculated. Here heating element 15
The effective electron emitting surface 1iS of the surface is considered to be a value much smaller than the actual geometric surface area, since local concentration of the emitted thermionic current is considered, and assuming that 5 = 10'm, Φ is given by equation (3).

・・・・・・・・・(3) Also, the melting surface temperature of the evaporation crucible 2 ■. is 2700'', the vapor density n0 at the evaporation surface is experimentally given as (4) from the vapor pressure vs. temperature characteristic chart.

no=5゜0X10 (pcs/7FL)...
...(4) Also, the melting surface temperature T. = 2700'',
Taking uranium atoms as an example, the root mean square velocity V of isotope particles in a vapor flow is given by equation (5).

Here, the atomic substance ff1m is 3.95x10-”5Kg
shall be.

Next, assuming that the evaporation surface @So of the evaporation crucible 2 is 107d, the number of evaporated particles per unit time, 8, is given by equation (6).

Φ −n −v−8□=2.7x10 (pcs/se
c) ・・・・・・・・・(6
) The problem in the separation operation is the number of ionized ions of various impurities contained in Φ.

The thermal ionization rate of various impurities is determined by the melting surface temperature T of the evaporation crucible 2. = several % of the total number of evaporated particles Φ, which is estimated based on the equation of thermal ionization equilibrium at 2700'K.
Within

On the other hand, the amount of impurity ions generated by collision ionization between the electrons included in the electron beam 4 and the majority of neutral atoms that are evaporated from the melting surface of the evaporation crucible 2 can be roughly understood as follows.

Beam current of linear electron gun 3 ■. When is 5A, the number of irradiated electrons per unit time is given by equation (1).

(7) Here, Φ is the collision ionization cross section between the fast electron and the neutral atom, σ. has been determined experimentally for uranium atoms, and according to the report, σ -101d! ?
! degree.

Therefore, assuming that the length of contact between the electron beam 4 and the vapor flow 5, that is, the reaction region length d, is 10-2 m, the number of impact ionizations per unit time, Φi, is calculated by equation (8).

Φ==n −d−cr −Φb=1.6x1010
e (pcs/5ec)...Old...(8
) However, in reality, one high-speed electron goes through the ionization process of repeating multiple collisions and ionizes multiple neutral atoms, and if we take into account that the increase coefficient due to multiple ionization is ξ, then the impact ionization of the vapor flow 5 is The rate η is given by equation (9).

Even if we assume that ξ=1~5X102 and take into account the amount of ions generated due to thermal ionization mentioned above, the ionization rate η is 10%.
It is judged that it will not exceed.

In the vicinity of the heating element 15, for example, in the case of uranium atoms, a recombination reaction between ionized uranium atoms and thermoelectrons occurs as shown in equation (10).

U” +e−−* (J+hν ・−−−−−
...-(10) Here, the recombination cross section σ, where the recombination reaction occurs, is 10 771.

As calculated above, from equations (3), (8), and (9), there is a relationship between the number of thermoelectrons Φ supplied from the heating element 15 and the number ηΦ of various impurity ions contained in the vapor flow 5. The relationship expressed by equation (11) holds true.

ηΦ, << Φ8...Singing...(11)
In other words, sufficient thermoelectrons are supplied to neutralize all charges of impurity ions in the vapor flow 5 generated by thermal ionization and impact ionization, so the vapor flow 5 is neutralized before being introduced into the photoreaction section. Be sexualized.

The subsequent separation procedure for the vapor stream 5 consisting only of neutral atoms or neutral molecules introduced into the photoreaction zone is the same as in the conventional method and apparatus.

According to this embodiment, the impurity ions contained in the vapor flow 5 are neutralized in advance by thermionic electrons emitted from the heating element 15 before being introduced into the photoreaction section. Therefore, the ions adsorbed to the recovery electrode 12 are only specific ionized isotopes photoionized by the laser beam 9.

Therefore, there is less risk that impurity ions will be entrained and adsorbed by the collection electrode 12, reducing the isotope separation efficiency or degrading the purity of the product, as in the prior art.

Furthermore, according to this example, the neutralization of the vapor flow is achieved by recombining impurity ions and thermoelectrons, which is a simple operation, and a complicated mechanism for removing impurity ions themselves from the system is not required. . Therefore, it is particularly effective when the separation operation is performed under operating conditions where the ionization rate of impurities is particularly high.

Next, another embodiment of the isotope separation apparatus according to the present invention will be described with reference to FIG. In the embodiment shown in FIG. 3, conductors 17 and 18 are arranged at predetermined intervals on the primary and secondary sides of the heating element 15 with respect to the flow direction of the steam flow 5. Each electrical conductor 17.18 has a heating element 15
Similarly, it is arranged in a direction perpendicular to the flow of steam flow 5, and
It has an opening 19 so as not to obstruct the flow of the steam flow 5.

Further, both of the two conductors 17 and 18 are set to a negative potential with respect to the heating element 15.

According to this embodiment, the negative potential distribution formed between the conductors 17 and 18 has the effect of confining thermoelectrons emitted from the heating element 15 into the space between the conductors 17 and 18. That is, it prevents thermionic electrons from diffusing to the peripheral area, maintains the thermionic swarm near the heating element 15, increases the electron density, increases the efficiency of contact with impurity ions, and reduces the vapor passing through this space. It promotes a reaction that neutralizes the charge of impurity ions contained in the flow.

Here, if the voltage Va applied to the conductors 17 and 18 is sufficiently larger than the energy ve of the thermoelectrons, diffusion of the thermoelectrons can be effectively prevented. That is, ve is (12)
It is given by Eq.

(12) Therefore, it is sufficient for the voltage Va to be applied to the conductors 17 and 18 to be several volts to more than ten volts. Furthermore, the density of the thermionic swarm can be optimally adjusted by appropriately controlling the voltage Va applied to the sN body.

Further, a further embodiment of the isotope separation apparatus of the present invention will be described with reference to FIGS. 4 and 5. In the embodiment shown in FIG. 4, the entire collection electrode 12 is housed in an "arM box 20. The shielding box 20 is formed in a box shape as illustrated in FIG. A through-flow port 21 is provided at a portion that serves as an inlet and an outlet for the steam flow 5 .

Further, as illustrated in FIG. 4, the shielding box 20 is connected to the electric power WA 22 so as to be set at a negative potential with respect to the ground potential.

In the device of the present invention, since the heating element 15 is provided, a large amount of thermoelectrons are generated within the device, and surplus electrons other than the thermoelectrons that were consumed by recombining with impurity ions are recovered. There is a possibility that it will be attracted toward the electrode, fill the photoreaction area, and recombine with the photoionized specific ionized isotope.

However, the shielding box 20 set to a negative potential has a function of electrically reflecting thermoelectrons while accepting an electrically neutral vapor flow into the shielding box 20, so that surplus thermoelectrons are Contamination into the reaction section 8 is blocked.

That is, recombination of the specific ionized isotope and thermionic electrons photoionized in the photoreaction region 8 is effectively prevented.

Therefore, the separation efficiency of specific isotopes at the recovery electrode is improved, and the concentration of impurities contained in the recovered product is reduced.
You can get products of excellent quality.

Note that in carrying out the present invention, no drastic modification or specification change is required to the configuration of an existing isotope separation device. In other words, it can be easily modified by simply installing a heating element.
The influence of impurity ions can be effectively reduced.

〔Effect of the invention〕

According to the isotope separation method and apparatus according to the present invention, a heating element is provided in the vapor flow path leading to the photoreaction part, and impurity ions contained in the vapor flow are pre-charged by thermoelectrons supplied from the heating element. Since it is neutralized, impurity ions are less likely to be adsorbed to the recovery electrode. Therefore, the separation efficiency of the isotope to be recovered is improved, and a product with excellent purity and quality can be obtained.

Further, since no electric field or magnetic field is applied in the processing operation for neutralizing the charge of impurity ions and reducing the influence of impurity ions, the influence of the Stark effect or Zeeman effect can be avoided. With Zunawa, the photoreaction rate is less likely to decrease due to the splitting of the excitation energy level of the specific isotope due to the above effect, and a decrease in the amount of recovered products can be prevented.

Therefore, the separation coefficient, which is an indicator of the operating efficiency of the isotope separation device, is high, and the purity and quality of the separated and recovered isotopes can be significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view schematically showing an embodiment of an isotope separation apparatus for carrying out the method of the present invention, FIG. 2 is a perspective view showing an example of the configuration of the heating element in FIG. 1, and FIG. FIG. 4 is a partial perspective view showing another embodiment of the isotope separation device of the present invention.
FIG. 5 is a cross-sectional view showing still another embodiment of the isotope separation device of the present invention, FIG. 5 is an enlarged perspective view of the shielding box in FIG. 4, and FIG. FIG. 7 is a perspective view showing an example of a schematic configuration of the separation device, FIG. 7 is a sectional view taken along the line ■-■ in FIG. 6, and FIG. 8 is an explanatory diagram showing one unit of atomic energy due to a photoionization reaction. 1...metallic uranium, 2...evaporation crucible, 3...
Linear gun, 4... Electron beam, 5... Steam flow, 6...
... Positive electrode, 7... Negative electrode, 8... Photoreactive part, g,
9a, 9b... Laser light, 10... Steam recovery plate, 1
1... Steam generator, 12... Recovery electrode, 13...
・Laser beam oscillation device, 1゛4...Steam flow path, 15・
...Heating element, 16...Heater power supply, 17...Conductor, 18...Conductor, 19...Opening, 20...Shielding box, 21...Flow through port, 22...・Power supply, A. B... Isotope atom, E... Ground level, El...
Excitation rate, E, . . . ionization level. Figure 1 Figure 2 Figure 3 Figure 4 Figure 6 Figure 7 Figure 8

Claims (1)

[Claims] 1. A vapor flow is generated by heating and evaporating a substance containing multiple types of isotopes, and the vapor flow is brought into contact with thermoelectrons in advance in a vapor flow path leading to a photoreaction part. After neutralizing the charge of impurity cations contained in the vapor flow, a vapor flow consisting of neutral atoms is introduced into the photoreaction section, and specific isotopes contained in the introduced vapor flow are selectively excited and ionized. Ionized isotopes are generated by irradiating the vapor flow with laser light, and the ionized isotopes are deflected in the direction of a predetermined collection electrode by applying an electric field to a collection electrode in which positive and negative electrodes are alternately arranged. An isotope separation method that separates and recovers specific isotopes. 2. Recovery in which a vapor generation device that heats and evaporates substances containing multiple types of isotopes to generate a vapor flow, and positive and negative electrodes are arranged alternately in parallel, and a photoreactive part is formed between these electrodes. A laser beam is irradiated onto the electrode, a heating element provided in the vapor flow path leading from the vapor generation device to the photoreaction section, and the vapor flow that has flowed into the photoreaction section of the recovery electrode to selectively select a specific isotope. an isotope separation device comprising a laser beam oscillation device that ionizes the vapor, the heating element being configured to supply thermoelectrons to impurity ions in the vapor flow generated by the vapor generation device. 3. The isotope separation device according to claim 2, wherein the heating element is constructed by winding a linear heater in the same plane while maintaining an insulating distance. 4. The isotope separation apparatus according to claim 2, wherein the heating element is a planar heater provided with steam through-holes. 5. The heating element has conductors arranged at a predetermined interval on the primary and secondary sides of the heating element with respect to the flow direction of the steam flow, and the conductor has a negative potential with respect to the heating element. An isotope separation device according to claim 2, wherein the isotope separation device is applied. 6. The collection electrode is housed in a shielding box having a through-hole at a portion serving as an inlet and an inlet for a vapor flow, and the shielding box is applied with a negative potential. Any one
The isotope separation device described in Section.