JP3340211B2 - Isotope separation method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an isotope separation method for separating a specific isotope atom of gadolinium element contained as a burnable poison in a part of a fuel rod constituting a fuel assembly used for a nuclear reactor. Regarding the device, in particular, to efficiently separate specific isotope atoms even when the light absorption wavelengths of multiple isotope atoms to be separated do not separate from each other and partially overlap and intersect. And a device for isotopic separation.

[0002]

2. Description of the Related Art Generally, gadolinia (gadolinium oxide) is used as a burnable poison to control the initial reactivity of a nuclear reactor in a part of fuel rods constituting a fuel assembly used in a light water reactor. Is used as a mixture with uranium oxide.

Conventionally, natural gadolinium has been used as such gadolinia, and the isotopic composition of natural gadolinium element and thermal neutron absorption cross section are shown in Table 1 below.

[0004]

[Table 1]

[0005] As shown in Table 1, natural gadolinium contains seven types of isotopes, of which Gd155 and Gd157 having large thermal neutron absorption cross sections play a role of reactivity control as neutron absorbing materials. .

[0006] In order to improve the characteristics as a burnable poison, Gd157 isotope having a particularly large thermal neutron absorption cross section, or enriched gadolinium in which the composition ratio of Gd157 and Gd155 isotopes is increased, or By reducing the composition ratio of isotopes such as Gd156 having a small neutron absorption cross section, it is conceivable to use gadolinium having a relatively high composition ratio such as Gd157, and the isotopes are separated by an atomic laser method. Attempts have been made.

The isotope separation process by the atomic laser method includes a metal material supply step of supplying a metal material for isotope separation, a metal vapor generation step of heating and melting the supplied metal material to generate a metal vapor. A selective excitation step of selectively exciting a specific isotope from the metal vapor, and a separation and recovery step of photo-ionizing (ionizing) metal atoms of the selectively excited specific isotope to recover an ionized isotope. Separated.

On the other hand, when a metal atom to be subjected to isotope separation is excited in a multi-step manner by a laser, an isotope shift is observed in this excitation. Therefore, in the isotope separation process, a specific isotope is irradiated with a laser beam for selective excitation in accordance with the energy level of the specific isotope to excite only the excited specific isotope, and the laser beam for selective excitation is emitted. By irradiation with another ionizing laser beam, the excited specific energy level is further increased, and only the specific isotope is ionized and ionized.

[0009] Isotopes include even nuclear isotopes and odd nuclear isotopes. The nuclear spin of the even nuclear isotope is zero, whereas the odd nuclear isotope has a nuclear spin. Some of the light absorption spectrum lines of the transition split into multiple lines and have an ultrafine structure. If the specific isotope has a hyperfine structure and the excitation spectrum width due to its main transition is wide, to selectively excite all the specific isotope by laser irradiation,
It is necessary to widen the line width (wavelength width) of the laser light so as to cover a wide excitation spectrum width, use a multi-mode laser light, or use a laser light whose frequency is swept at high speed.

[0010]

However, the gadolinium atom contains seven types of isotopes as shown in Table 1, and their isotope shifts are not so large. Due to the spread of the hyperfine structure of the absorption wavelength spectrum, the light absorption wavelengths of different isotopes partially overlap and intersect.
Sufficiently high separation performance cannot be obtained for certain odd-numbered nuclear isotopes such as d157.

It is also possible to use a laser having a very narrow wavelength width to selectively excite, ionize, and separate in synchronization with a part of the light absorption spectrum split by the ultrafine structure of the Gd157 isotope. In that case, the ratio of atoms to be separated is small, and the separation efficiency is poor. There is also a method of selectively ionizing and removing Gd156 using a laser having a narrow wavelength width. However, Gd155, 157, 158, 160, and other isotopes are mixed and cannot be separated, so that Gd156 cannot be used as a burnable poison. Of good composition cannot be obtained.

The present invention has been made in view of the above circumstances, and its object is to mix a plurality of isotopes,
For example, gadolinium metal atoms whose isotope shift is not sufficiently large, odd-numbered nuclear isotopes of Gd157 and Gd155 having a hyperfine structure, and Gd156 and Gd having no hyperfine structure
When the optical absorption wavelengths of even nuclear isotopes such as 158 are partially overlapped and intersected, specific isotopes such as Gd157 and Gd155 can be economically and efficiently separated with high separation performance. An object of the present invention is to provide a body separation method and a device therefor.

[0013]

The present invention is configured as follows to solve the above-mentioned problems.

The invention described in claim 1 of the present application (hereinafter referred to as the first invention)
Single light absorption peak wavelength) of that invention is, and even-nuclear isotopes having a single light absorption peak wavelength, the even-nuclear isotopes
In isotope separation method and odd nuclear isotopes, vaporized by heating the metal raw material containing, allowed to respectively separate the isotopes by irradiating a laser beam to the vapor stream having a light absorption wavelength region including the steam At least two photoreaction portions are provided along the flow path of the flow, and the photoreaction portion closer to the vapor flow generation source is provided with a laser beam having a frequency tuned to the single light absorption peak wavelength, The even nuclear isotope is excited by irradiating a laser light having a frequency modulation width as narrow as the Doppler width of one light absorption peak wavelength, and further, the even nuclear isotope is separated by ionization by a laser light multi-step excitation method. On the other hand, the other photoreaction portion is irradiated with a laser beam having a wide frequency width over the wavelength region including the single light absorption peak wavelength, and further, the odd nuclear isotopes are excited by a multi-step excitation method. And ionize And recovering Te.

Further, in the invention described in claim 2 of the present application (hereinafter referred to as a second invention), the even nuclear isotope is Gd156.
And Gd158.

Further, in the invention according to claim 3 of the present application (hereinafter referred to as a third invention), the odd-numbered nuclear isotope is Gd157.
And Gd155.

Furthermore, the invention described in claim 4 of the present application (hereinafter, referred to as a fourth invention) provides an even-numbered nuclear isotope having a single light absorption peak wavelength and a single-photon absorption of the even-numbered nuclear isotope. An odd-number nuclear isotope having a light absorption wavelength region including a peak wavelength, and heating and evaporating a metal raw material containing the same, an isotope separation apparatus that separates the respective isotopes by irradiating a laser beam to the vapor stream, A laser having a frequency tuned to the single light absorption peak wavelength is provided in the photoreactor provided at at least two places along the flow path of the vapor flow and the photoreactor closer to the vapor flow source. Exciting the even nuclear isotopes by irradiating light, or laser light having a frequency modulation width as narrow as the Doppler width of the single light absorption peak wavelength thereof,
Further, the even-numbered nuclear isotope is separated by ionization by laser light multi-step excitation, and the other light-reactive portion has a laser light having a wide frequency width over the wavelength region including the single light absorption peak wavelength. And a laser system that excites the odd-numbered nuclear isotopes by multi-step excitation to ionize them, and an isotope recovery unit that recovers each of the ionized isotopes.

In the invention described in claim 5 of the present application (hereinafter referred to as a fifth invention), the even nuclear isotope is Gd156.
And Gd158.

Further, in the invention described in claim 6 of the present application (hereinafter referred to as a sixth invention), the odd nuclear isotope is Gd157.
And Gd155.

[0020]

In the photoreaction section closer to the vapor generation source, the laser system is fixed to a frequency tuned to the single optical absorption peak wavelength of, for example, Gd156 alone or even nuclear isotopes such as at least one of Gd156 and Gd158. Laser light, or a laser light having a narrow frequency modulation width of about the Doppler width of the single light absorption peak wavelength, and further irradiates Gd156 alone or Gd156 and Gd15.
The both even-numbered nuclear isotopes of 8 are ionized by multi-stage excitation and separated and recovered by the isotope recovery means.

On the other hand, the other isotope atoms pass through the first photoreaction portion without being excited, but the second isotope atoms separated from the evaporation flow source are not excited.
Is irradiated from the laser system, for example, a laser beam having a wide frequency modulation width to cover the light absorption wavelength region of the ultrafine structure of at least one of Gd157 and Gd155 alone or Gd157 of the odd nucleus. ,
These isotopes are excited in multiple stages, ionized, and recovered by the isotope recovery means.

Therefore, the present invention provides an even-numbered Gd156 having a single light absorption peak wavelength within a wide light absorption wavelength region of an odd-numbered nuclear isotope such as Gd157 having a hyperfine structure.
The isotope is first excited and ionized, then Gd157
Since the isotopes are excited and ionized, both the separation performance and the efficiency of these isotopes can be improved.

Further, it is sufficient to provide only a plurality of photoreaction sections along the atomic vapor flow path, and it is not necessary to provide a double separation cell including a metal vapor generator, so that an increase in cost can be suppressed.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 2 is a diagram showing the principle of an embodiment in which the present invention is applied to gadolinium isotope separation. In FIG. 2, the gadolinium isotope separation apparatus comprises a separation cell 1 and a laser system 2. ing.

The separation cell 1 is provided in a vacuum vessel 1a with a metal vapor generator 3, which is a vapor generation source, and two upper and lower parts of the isotope recovery means.
The stage contains the ion recovery electrode plates 4a and 4b, the neutral atom recovery plate 5, and the like.

The metal vapor generating device 3 generates a metal vapor by heating a gadolinium raw material containing a plurality of isotopes with an electron beam or the like. The first and second photoreaction portions 7a and 7b are provided between the negative and positive electrode plates of each of the ion collection electrode plates 4a and 4b.
Are formed respectively. Each of these photoreaction sections 7a,
The laser system 2 irradiates the laser system 2 with the combined laser beams 8a and 8b output by combining the selective excitation laser beam and the ionized laser beam from the side openings of the ion recovery electrode plates 4a and 4b. It has become.

FIG. 1 shows an example of a light absorption spectrum of gadolinium Gd atoms separated by the isotope separation device shown in FIG. The synthetic laser beam 8a applied to the first photoreactor 7a closer to the vapor source is a laser beam fixed at a frequency tuned to the single light absorption wavelength of the Gd156 isotope atom, or a symbol in FIG. It is a laser beam having a frequency modulation width as narrow as the Doppler width as indicated by La.

On the other hand, the second photoreactor 7 remote from the vapor source
b, the combined laser beam 8b is denoted by Lb in FIG.
As shown in the figure, the laser light has a wide frequency modulation width capable of covering the light absorption wavelength region of the ultrafine structure of the odd nuclear isotope atoms of Gd157.

The Gd156 isotope atom having a single light absorption wavelength is ionized by the multi-step excitation method in the first photoreaction portion 7a, and its ions are separated and collected by the lower ion collection electrode plate 4a. G with hyperfine structure
The d157 isotope atom is ionized by the multi-step excitation method in the second photoreaction portion 7b, and the ion is separated and collected by the upper ion collection electrode plate 4b. Gd not ionized by the first and second photoreactors 7a, 7b
Some of the other isotope neutral atoms, such as 154, Gd158, and Gd160, adhere to the electrode plates 4a and 4b, but in most cases, the neutral atoms placed above the electrode plates 4a and 4b without passing through them. Collected by collection 5.

FIG. 3 shows an embodiment of a gadolinium isotope separation apparatus embodied based on such a principle, which is substantially the same as the configuration shown in the principle diagram of FIG. In the generator 3, a gadolinium metal raw material 10 containing a plurality of isotopes is accommodated in an evaporation crucible 9 formed of a copper or tungsten material or the like.

An electron beam 12 output from an electron gun 11 is deflected by a deflection magnetic field coil 13 such as a Helmholtz coil to irradiate the metal raw material 10. That is, the metal material 10 is heated and melted by the irradiation of the electron beam 12 to be melted and evaporated, and the vapor flow of the evaporated metal material 10 rises with a predetermined width to form the vapor flow path 6. I have.

In the vapor flow path 6, ion recovery electrodes 4a and 4b are respectively installed at two places above and below the vapor flow path 6, and a first and second photoreaction section 7 is provided between each of the cathode plate and the anode plate.
a and 7b are respectively formed. Each of the photoreaction portions 7a and 7b is provided with laser beams 8a1 and 8b1 for selective excitation and laser beams 8a1 and 8b for ionization from the laser system 2.
2 are irradiated, and the irradiation of the first selective excitation laser light 8a1 selectively causes, for example, metal atoms of an even nuclear isotope of Gd156 by an optical resonance reaction. By irradiating the excited Gd156 isotope metal atom with the laser beam 8a2 for ionization, the energy level of the metal atom is increased and ionized. The ionized Gd156 isotope becomes a positively-charged ion isotope, and becomes the first ion collection electrode 4a.
By the electric field formed between the negative electrode and the anode plate, it is adsorbed and collected by the collecting electrode on the negative electrode side.

On the other hand, metal atoms that are not ionized in the first photoreaction portion 7a are not affected by the electric field, and therefore pass through the electrode space of the first ion collection electrode plate 4a and further pass through the second ion collection electrode plate 4a. It passes between the anode and the anode plate of the electrode 4b. Then, in the second photoreaction portion 7b of the second ion recovery electrode 4b, the second selective excitation laser beam 8b
By the irradiation of 1, the metal atoms of, for example, the odd nuclear isotope of Gd157 are selectively excited by an optical resonance reaction, and the excited metal atoms of the odd nuclear isotope are further irradiated with the ionizing laser beam 8b2. By doing so, those atoms are ionized, and are adsorbed and collected by the collecting electrode on the negative electrode side by the electric field formed between the anode of the ion collecting electrode 4b and the anode plate.

Neutral metal atoms of other isotopes, such as Gd154, Gd158, and Gd160, which are not ionized even in the second photoreaction portion 7b, pass through the space of the second ion recovery electrode 4b and move further upward. They are collected and collected by the installed neutral atom recovery plate 5.

On the other hand, the laser system 2 comprises two sets of pumping lasers 14 (14-1, 14-1) for selective excitation and ionization.
14-2) and two sets of single mode wavelength tunable lasers 1
5 (15-1, 15-2), and a single-mode laser beam from this laser device with a wavelength sweep width covering the spread of the light absorption spectrum of isotope atoms such as Gd157 to be separated. Frequency modulation device 16 (16a1,1) for generating laser light of necessary pulse energy
6a2, 16b1, 16b2) and a pulse laser amplifier 17 (17a1, 17a2, 17a2, 17a2,
17b1, 17b2).

As the pumping laser 14, a gas laser such as a copper vapor laser or an excimer laser is used for its characteristics such as a high output and a high pulse repetition rate. However, a solid laser such as a YAG laser or a titanium / sapphire laser is used. Semiconductor lasers and the like can be used if their characteristics are improved in the future. As the single-mode tunable laser 15, a dye laser is used.

Next, the operation of this embodiment will be described.

First, a gadolinium raw material 10 in a crucible 9 of a metal vapor generator 3 is applied from an electron gun 11 to an electron beam 1.
2 is irradiated and heated, further melts and evaporates, and flows up the metal vapor flow path 6.

On the other hand, the wavelength tunable laser 15-1 of the laser system 2 emits an oscillation wavelength laser beam having a light absorption wavelength for selective excitation of Gd atoms.
5-2 respectively emits laser light having an oscillation wavelength of a light absorption wavelength for ionization. Frequency modulation devices 16a1, 16a2
Is a laser light for selective excitation and ionization of Gd156, a laser light having a wavelength sweep width of about Doppler spread at a single light absorption wavelength for selective excitation and ionization, and a laser light for selective excitation and ionization of Gd157. A laser beam having a wavelength sweep width that covers the region including the Doppler spread is generated in the light absorption wavelength region having.

As the frequency modulation device 16, LiTaO
A method in which a high-voltage pulse voltage is applied to an electro-optical crystal such as LiNbO ₂ or LiNbO ₂ is used, and the modulation frequency width can be appropriately set according to the magnitude of the applied voltage.
A laser pulse amplifier 1 for amplifying these laser beams
As 7, a dye laser amplifier having a large pulse amplification factor is used, and a laser beam having a large pulse energy necessary for sufficiently exciting atoms is obtained.

Then, the wavelength of the first selective excitation laser beam 8a1 output from the laser system 2 is set to, for example, the Gd156 light absorption peak wavelength of the Gd atom light absorption spectrum shown in FIG. The first photoreaction portion 7a of the recovery electrode 4a irradiates the Gd vapor stream to selectively excite only Gd156, and at the same time, ionizes and ionizes the ionized laser beam 8a2 to irradiate it.
The Gd156 isotope ion is transferred to the first ion recovery electrode 4
It is adsorbed and collected on the negative electrode a.

G not ionized by the first photoreactor 7a
Other isotope atoms such as d157
The electrode passes through the electrode space a, and reaches the second photoreactor 7b of the second ion recovery electrode 4b above the electrode space.

The second photoreactor 7b irradiates the Gd vapor flow with the laser beam 8b1 for selective excitation shown in FIG. 3 covering the wavelength of the light absorption hyperfine structure spectrum of Gd157 shown in FIG. Gd157 isotope atoms are selectively excited, and the Gd157 isotope ions ionized by the ionizing laser beam
And is adsorbed on the negative electrode of the ion collection electrode 4b.
Each photoreaction section 7a, 7 of these ion recovery electrodes 4a, 4b
Other isotope atoms, such as Gd158, which are not collected without being ionized in b, pass through the second photoreaction unit 7b, and collide with the neutral atom collection plate 5 above and are collected.

Therefore, according to the present embodiment, even when the light absorption spectrum of the isotope to be separated cannot be separated because it partially overlaps with the light absorption wavelength of another isotope, the isotope to be separated can be efficiently separated. The pumping laser 14 and the tunable laser 15 can be separated from each other.
It is sufficient to provide only two sets of the frequency modulation device 16 and the laser pulse amplifier 17 and divide and introduce the laser whose wavelength has been set from the wavelength tunable laser 15 without having to increase the entire laser system. Compared with the conventional system, the economic efficiency is not greatly reduced.

As shown in FIG. 3, the gadolinium isotope separation apparatus of this embodiment is provided in a single separation cell 1 in a manner similar to a conventional isotope separation apparatus, in which a set of metal vapor generators 3 and one A neutral atom recovery plate 5 is provided, and only the ion recovery electrode plate 4 is provided.
Only the a and 4b need to be installed at two locations along the atomic vapor flow path 6, and the separation cell 1 including the metal vapor generator 3 is required.
It is not necessary to provide two sets, so that cost increase can be suppressed as compared with the conventional apparatus.

In this embodiment, the example in which the Gd isotope is ionized by two-wavelength two-step excitation has been described. However, the present invention is not limited to the number of wavelengths and the number of steps. Various multi-step excitation methods such as an excitation method or a four-wavelength four-step excitation method may be used. However, in this case, the laser system 2 requires three or four pumping lasers 14 and tunable lasers 15, respectively.

In the isotope separation device shown in FIG.
The first photoreaction portion 7a is irradiated with a laser beam fixed at a frequency tuned to a single light absorption peak wavelength of a Gd156 isotope atom or a single mode laser beam having a narrow frequency modulation width, and is irradiated in two steps or Gd156 by three-step excitation method
The atoms are ionized to be separated and removed, and the second photoreactor 7b is irradiated with laser light having a frequency modulation width covering the ultrafine structure light absorption wavelength of both odd nuclear isotope atoms of Gd157 and Gd155. Both atoms can be ionized and ionized by a two-step or three-step excitation method, and the ions can be recovered and separated by the second ion recovery electrode 4b.

Further, in the present invention, Gd156 and Gd1 are included in the ultrafine structure light absorption spectrum of Gd157.
58, each having a single light absorption peak, and when the ultrafine structure light absorption wavelengths of Gd155 overlap each other, Gd157 and Gd1 are obtained by the following method.
55 can be separated and recovered.

That is, of the two ion recovery electrode plates 4a, 4b and the photoreactors 7a, 7b provided along the vapor beam flow path shown in FIG. 2, the first photoreactor 7a close to the vapor generator is provided. Then, two frequency mode laser beams 8a tuned to the two light absorption wavelengths of Gd156 and Gd158
And ionization is performed by a two-step excitation method or a three-step excitation method, and those ions are collected and removed by the first ion collection electrode plate 4a, and then Gd15 is collected by the second photoreaction unit 7b.
7 and Gd155 are irradiated with laser light 8b having an optical frequency modulation width covering the ultra-fine structure light absorption spectrum of the odd nuclear isotope atoms to ionize the atoms by a two-step excitation method or a three-step excitation method. 2 ion recovery electrode plate 4b
, Gd156, Gd158, Gd154, and Gd160 can be efficiently separated from other isotope atoms. Here, the two frequency mode laser beams can be obtained by converting a single mode laser beam by an optical frequency modulator using an acousto-optic device or an electro-optic device.

Further, according to the present invention, even when the light absorption wavelengths of a large number of isotopes intersect, the number of the ion recovery electrodes and the photoreactive portions along the atomic vapor flow path is increased by the same method. The desired isotope can be separated and recovered.

In this embodiment, the isotope separation of the gadolinium Gd atom has been described. However, in the present invention, zirconium (Zr), uranium (U), plutonium (Pu), etc. The invention can be applied not only to a single element but also to a case where a plurality of elements are mixed to complicate the light absorption spectrum.

Next, according to the present invention, zirconium (Z
An example of a method for depleting a specific isotope of r) (for example, Zr91) will be described.

Since zirconium (Zr) has a small thermal neutron absorption cross section and good metallurgical properties, it is widely used as a core material for a fuel rod cladding tube, a pressure tube and the like of a reactor. Natural Zr has a mass number of 90, 91, 92, 9
Consisting of 4,96 five isotopes, Zr91 has a natural composition ratio of about 11%, but has a thermal neutron absorption cross section of about 75% of the total Zr. By separating Zr91 from other isotopes and reducing the composition ratio, the effective thermal neutron absorption cross section can be reduced, which is useful for improving the operating characteristics of the reactor core, improving the neutron economy, extending the fuel cycle, and the like.

However, as shown in an example of the light absorption spectrum of Zr atom in FIG. 5, in the case of Zr, the dispersed light absorption spectrum of Zr91 includes Zr90, Zr92, Zr94, and Zr90.
The light absorption peak of the even nuclear isotope of Zr96 is included.

Therefore, the first photoreaction section near the Zr vapor generation source irradiates a laser beam having a frequency D in FIG.
First, Zr90 is ionized and collected on the collection electrode. The next second
Is irradiated with a laser beam having a frequency modulation width in the extended region of E in the figure, and the isotopes of Zr92, Zr94, and Zr96 are ionized and collected by the collection electrode. As a result, the remaining Z
r91 can be separated and removed.

[0057]

As described above, according to the isotope separation method according to the present invention, the isotope shift is not sufficiently large as in the case of gadolinium metal atoms in which a plurality of isotopes are mixed, and the ultrafine structure Even if the optical absorption wavelengths of the odd nuclear isotopes having the above and the even nuclear isotopes without the hyperfine structure are partially overlapped and intersected, the specific isotope atoms such as Gd157 can be efficiently separated. Can be concentrated.

Further, according to the isotope separation device of the present invention, it is only necessary to provide a plurality of photoreactors along the metal vapor flow path, and there is no need to provide a plurality of separation cells including the metal vapor generator. Cost increase can be minimized.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a light absorption spectrum of gadolinium atoms to be separated separated by the isotope separation device of FIG. 2 or FIG.

FIG. 2 is a principle view showing the principle of a gadolinium isotope separation method and a separation apparatus according to the present invention.

FIG. 3 is a configuration diagram showing one embodiment of a gadolinium isotope separation apparatus according to the present invention.

FIG. 4 is a light absorption spectrum diagram of a gadolinium atom to be separated in another embodiment of the present invention.

FIG. 5 is a light absorption spectrum diagram of zirconium atoms to be separated in another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Separation cell 2 Laser system 3 Steam generator 4a, 4b 1st, 2nd ion recovery electrode 5 Neutral atom recovery plate 6 Atomic vapor flow 7a, 7b 1st, 2nd photoreaction part 8a, 8b Synthetic laser beam 8a1 , 8b1 Laser light for selective excitation 8a2, 8b2 Laser light for ionization 9 Crucible 10 Metal raw material 11 Electron gun 12 Electron beam 13 Magnetic field coil for deflection 14 Pumping laser 15 Wavelength variable laser 16 Frequency modulator 17 Laser pulse amplifier

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B01D 59/00-59/50

Claims (6)

(57) [Claims] And 1. A even-nuclear isotope with a single light absorption peak wavelength, the single optical absorption peak wavelength of the even-nuclear isotopes including
And odd nuclear isotopes having no light absorption wavelength region, vaporized by heating the metal material containing, in isotope separation method in which separate each said isotope by irradiating a laser beam to the vapor stream, the vapor stream At least two photoreaction portions are provided along the flow path of the laser beam, and the photoreaction portion closer to the vapor flow generation source is provided with a laser beam having a frequency tuned to the single light absorption peak wavelength, The even nuclear isotope is excited by irradiating laser light having a frequency modulation width as narrow as the Doppler width of the light absorption peak wavelength, and further, the even nuclear isotope is separated by ionization by a laser light multi-step excitation method. The other photoreactor is irradiated with a laser light having a wide frequency width over the wavelength region including the single light absorption peak wavelength, and further, the odd-numbered nuclear isotope is excited by a multi-step excitation method. Let it ionize Isotope separation method characterized by yield. 2. The even nuclear isotopes are Gd156 and Gd158.
The isotope separation method according to claim 1, wherein the method is at least one of the following. 3. Odd nuclear isotopes are Gd157 and Gd155.
The isotope separation method according to claim 1, wherein the method is at least one of the following. 4. A even-nuclear isotopes having a single light absorption peak wavelength, the single optical absorption peak wavelength of the even-nuclear isotopes including
And odd nuclear isotopes having no light absorption wavelength region, vaporized by heating the metal material containing, in isotope separation apparatus allowed to separate each said isotope by irradiating a laser beam to the vapor stream, the vapor stream A light reaction portion provided at at least two places along the flow path, and the light reaction portion closer to the vapor flow generation source, a laser beam having a frequency tuned to the single light absorption peak wavelength, or The even nuclear isotope is excited by irradiating laser light having a frequency modulation width as narrow as the Doppler width of the single light absorption peak wavelength, and further ionizing by laser light multi-step excitation to separate this even nuclear isotope. On the other hand, the other photoreaction portion is irradiated with laser light having a wide frequency width over the wavelength region including the single light absorption peak wavelength, and further, the odd nuclear isotope is ionized by multi-step excitation. Les The system and, isotope separation apparatus characterized by having a isotope recovery means for recovering the ionized each isotope was respectively. 5. An even nuclear isotope comprising Gd156 and Gd158.
The isotope separation device according to claim 4, wherein the isotope separation device is at least one of the following. 6. Odd nuclear isotopes are Gd157 and Gd155.
The isotope separation device according to claim 4, wherein the device is at least one of the following.