JPS6197021A - Uranium enriching device by laser method - Google Patents

Abstract

PURPOSE:To increase the availability rate of uranium vapor and to improve the enriching performance by controlling the vaporization of metallic uranium vapor in an atomic process using metallic uranium. CONSTITUTION:A filament 1 for emitting an electron beam 2 and a deflecting magnetic field 3 for deflecting the electron beam 3 are provided in a cell 15. A crucible 4 for contg. metallic uranium 5 is arranged in the deflecting magnetic field 3. A vaporization part for generating a uranium atomic beam 6 is formed in the crucible 4. Plural atomic beam guided plates 16A, 16B, and 16C are arranged at an angle of theta=theta0 (0 deg.<theta<90 deg.) to the flow of the atomic beam to control the moving direction of the atomic beam 6. Consequently, the amt. of excited and ionized metallic uranium vapor is increased and the availability rate of the uranium vapor is improved. Accordingly, the enriching degree of <235>U is improved, and the separation of <235>U and <238>U is enhanced.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to a uranium enrichment device using a laser method.

[Technical background of the invention and its problems] Uranium isotope separation and enrichment technology using a laser method has a much greater separation capacity than conventional gas diffusion methods, nozzle methods, chemical exchange methods, centrifugation methods, etc. It is said that there is no need to build a cascade. There are two ways to enrich uranium using this laser method: an atomic method using metallic uranium and a molecular method using uranium hexafluoride gas.

An example of the operation of a uranium enrichment device using a laser method in the current atomic method will be explained with reference to FIG. That is, an electron beam 2 is irradiated from a filament 1, which is disposed in a separation cell 15 which surrounds the entire structure and is indicated by a frame, onto metal uranium 5 housed on a fuselage 4 via a deflection magnetic field 3.

The metallic uranium 5 bombarded by this electron beam 2 is
It is heated to 2,000'' K to 3,000' K and travels upward as a metallic uranium atomic beam 6. In this atomic beam 6, 238U atoms 7
and 235U atoms 8 are in a mixed state.

A selective excitation laser 9 having a frequency corresponding to the absorption line of 235 U in this atomic beam 6 is irradiated.

This selective excitation laser beam 9 attempts to concentrate 2!
Only S U is excited.

Next, ionizing laser light 10 is irradiated to ionize the excited 2MU. These two types of laser beams 9 and 10 ionize the atomic beam U8 in the atomic beam 6 and transform it into bamboo U+11.

Now, when an electric field is created for the atomic beam 6 containing these ions using the ground electrode 12 and the negative electrode 13, it is ionized (＼・ru235 (only J÷11 is electrostatically attracted to the negative electrode 1i13, Ultimately, it is adsorbed onto the surface of the negative electrode 13.

On the other hand, the unionized 24U7 is not affected by this electric field, so it travels straight and is collected by the neutral atom collection plate 14.

By the way, in the conventional uranium enrichment equipment using the atomic method,
The atomic beam of metallic uranium heated by the electron beam does not all travel above the crucible and be irradiated by the selective excitation laser or ionization laser, but instead travels in all directions at an angle of 180° from the upper exit of the crucible. Well, these crucibles,
Since the particles scatter into the separation cell 15, which houses the recovery electrode, recovery plate, etc. and is maintained in a high vacuum, the following problems arise.

First, metallic uranium adheres to the inner wall of the separation cell, resulting in a decrease in the degree of vacuum within the separation cell. Second, since not all of the atomic beams are irradiated with the laser, not only the efficiency of using metallic uranium vapor decreases, but also the amount of usU that is selectively excited and ionized decreases, resulting in a decrease in enrichment. be.

[Objective of the Invention] The present invention has been made in view of the above circumstances, and it is possible to reduce the uranium vapor by limiting the evaporation of metallic uranium vapor in the case of the atomic method using metallic uranium in a uranium enrichment device using a laser. It is an object of the present invention to provide a uranium enrichment device using a laser method, which improves the effective utilization rate and improves the enrichment performance.

[Summary of the Invention] That is, the present invention provides a crucible that is disposed in a separation cell and evaporates filaments with an electron beam, and has a highly heat-resistant and corrosion-resistant material that can control the traveling direction of the vapor beam on both sides of the outlet of the metallic uranium vapor beam. This is a uranium enrichment device characterized by having at least two very thin rectangular parallelepiped guide plates made of material such as tantalum installed in the direction of the steam beam. □ [Embodiment of the Invention] An embodiment of the apparatus according to the present invention will be described below with reference to FIGS. 1 and 2. The same parts in FIG. 1 as in FIG. 3 are given the same reference numerals.

That is, in the present invention, a filament 1 that generates an electron beam 2 and a deflection magnetic field 3 that deflects the electron beam 2 are provided in a cell 15. A crucible 4 containing uranium metal 5 is arranged within the deflection magnetic field 3 . This melting pot 4
An evaporation section is formed in which a uranium atomic beam 6 is generated. In order to control the traveling direction of the atomic beam 6, a plurality of atomic beam guide plates 16 (16A, 16B, 16C) are provided.
) is installed above the crucible 4 so as not to protrude from the wall of the separation cell 15. The guide plates 16A, 16B', and 16G are held concentrically by supports (not shown). This support is fixed to the floor or side wall surface of the separation cell as required. Above the guide plates 16A, 16B, and 16G, a selective excitation laser beam 9 having a wavelength that is absorbed only by the l3SU atoms 8 and an excited 2! A photoreaction section having an ionizing laser beam 10 for ionizing SU atoms is arranged.

A negative electrode 13 collects the ionized 29U+ ions.
A 235U collection unit is provided which is made up of an installed electrode 12 that generates an electric field between the 23aU and the negative electrode 13, and a neutral atom collection plate 14 that collects unexcited 23aU.
is provided.

Furthermore, to explain in detail the guide plates 16A, 16B, and 16G that control the atomic beam, which are the core of the present invention, these guide plates 16A, 16B, and 16G have high heat resistance and corrosion resistance, and are very thin. , for example, is made of a material such as tantalum, and has a surface that totally reflects the atomic beam. The atomic beam guide plates 16A and 168116G are arranged above the concave edges of both sides of the upper surface of the crucible 4 at an angle of Q'< θ < 90° with respect to the atomic beam traveling direction.
The first guide plate 16A is arranged at an angle in the range of
Furthermore, second and third guide plates 16 are formed parallel to the guide plate 16A along the center of the crucible 4 from this first guide plate 16A.
Place B and 16G respectively.

Next, the operation of the uranium enrichment apparatus using the laser method having the above configuration will be explained.

That is, a large current electron beam 2 is generated from a filament 1 and irradiated onto metal uranium 5 on a crucible 4, which is deflected by a deflecting magnetic field 3. The metallic uranium 5 heated by the electron beam 2 becomes an atomic beam 6 having a density distribution as shown in FIG.

That is, if the atomic beam guide plates 16A, 168° 160 are not present, the atomic beam in the range of width ro between the installation electrode 12 and the cathode 13 is irradiated with the laser and collected on the cathode 13. However, the guide plates 16A, 16B, 16G
is expressed as θ−θo(0@<θ<9
By arranging the atomic beams at
The amount of 235U reflected by C and excited and ionized by the selective excitation laser 9 and the ionization laser 10 and collected on the cathode corresponds to the distance r+ (r+>r,) of the atomic beam density in Fig. 2. , the amount of separation is increased compared to the case without the atomic beam guide plate.

In Fig. 2, R is the spreading width of the atomic beam, ra is the width between the installed electrode and the cathode, and rl is the angle of the guide plate.
The width corresponds to the amount of the atomic beam that would be collected by the cathode if

"Effects of the Invention" As detailed above, according to the present invention, the radiation angle of the uranium vapor beam generated by the crucible for heating and vaporizing metallic uranium is reduced, and the radiation direction of the vapor beam is restricted. . Therefore, encouragement. The amount of uranium metal vapor generated and ionized increases, and the effective utilization rate of uranium vapor increases.
Improved U enrichment, 2! This has the effect of improving the separation performance between '5U and 2''U.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of a uranium enrichment device using a laser method according to the present invention, and FIG. 2 is a density distribution diagram showing the relationship between the density and distance of the metal uranium vapor beam of the device in FIG. 1. , FIG. 3 is a block diagram of a conventional uranium enrichment device using a laser method. 1...Filament 4...
・・・・・・Crucible 5・・・・・・・・・Uranium metal 9・・・・・・
...Selective excitation laser beam 10...
...Ionizing laser beam 12......Installed electrode 13...Cathode electrode 15...Separation Cell 16.16A,
16B, 16C ・・・・・・Electron beam guide plate agent Patent attorney Sa Suyama - Figure 1 δ

Claims (1)

[Claims] (1) Metallic uranium is placed in a separation cell and placed in a crucible, bombarded with an electron beam and evaporated to generate an atomic beam, which is excited by a ^2^3^5U selective excitation laser. In a uranium concentrator that irradiates an ionizing laser that ionizes ^2^3^5, an angle of 0° < θ < 90 with respect to the atomic beam traveling direction is placed above both sides of the metal uranium vapor beam exit part of the crucible. A uranium enrichment device using a laser method, characterized in that a plurality of atomic beam guide plates are arranged in parallel with an angle in the range of .