JPH0516889B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an isotopic element recovery device, and in particular, a device for recovering isotopic elements, in particular a device for ionizing only specific isotopes by irradiating a vapor atmosphere of isotopic elements with a laser beam and applying a magnetic field. This relates to a recovery device for a device that collects waste.

[Background of the invention]

A vapor stream containing multiple uranium isotopes is irradiated with laser light to generate the selected isotope (in this case
A typical method and device for selectively separating isotopic elements by exciting and ionizing U ²³⁵ ) was published in Japanese Patent Publication No. 57-13331.
No. In this example, we selectively separate
A collection plate is proposed as a mechanism to collect U ²³⁵ and other uranium isotopes. separated
The collection plate for only U ²³⁵ and the collection plate for other uranium isotopes are periodically cleaned to collect separated U ²³⁵ and other uranium isotopes separately.

This precedent only mentions washing the plate periodically, and it is unclear whether the plate should be removed every time, even if it can be used at a laboratory level.
No consideration has been given as to whether it is competitive in terms of efficiency and cost on an industrial level. Therefore, although the possibility of separation was revealed, the separated U ²³⁵
The mass production technology remains unresolved.

To mass produce separated U ²³⁵ on an industrial level,
It is important to simplify the production process and perform continuous collection. An advantageous method for this purpose is to maintain the collection plate above the melting temperature of the uranium isotope, that is, 1405 [〓], and to collect the collected U ²³⁵ and other uranium isotopes by flowing them in a molten state. It is thought that there will be. Further, according to this method, since the collection plate can be kept clean, the time required for cleaning can be reduced, and the collection plate can be collected in a constant state, which is an advantage.

[Purpose of the invention]

An object of the present invention is to provide an isotope element recovery device that allows continuous recovery and significantly reduces the time required for maintenance.

[Summary of the invention]

It is advantageous for the isotope element recovery device to be capable of continuous recovery from the viewpoint of productivity. In this section, we will use uranium metal isotope as an example of an isotopic element.

The uranium metal isotope has a melting point of 1405 [〓],
If the temperature of the collection plate is maintained above the melting point, the uranium isotope element will remain in a molten state after adhering to the collection plate. If the collection plate is tilted in advance, the uranium isotope elements in the molten state will be
Since it flows down while adhering to the collection plate, it can be collected at the bottom of the collection plate to facilitate continuous collection. In addition, since the uranium isotope attached to the recovery plate flows, the uranium isotope does not adhere to the adhesion surface of the recovery plate in a layered manner, and collection under the same conditions is always possible in a clean state.

The practical problem in realizing a uranium isotope recovery device is the heat resistance and corrosion resistance of the material used for the recovery plate. It can be manufactured. For example, when using tungsten,
Regarding heat resistance, the melting point is 3653 [〓] (Incorporated Association, Japan Institute of Metals: "Metal Data Book", Maruzen Co., Ltd., published on July 20, 1970, p. 10). On the other hand, regarding corrosion resistance, HBMcIntosh, KQ
Bagley: “J.Inst.Metals”, 84
(1956), 251. According to
(Since it is approximately 167 [hr] or more, it is subject to time restrictions, but countermeasures such as increasing the plate thickness are easily possible.Therefore, problems regarding heat resistance and corrosion resistance regarding materials are high. This can be avoided by appropriately selecting a metal with a melting point.Furthermore, when using a metal with a high melting point for the collection plate, the resistance of 40 [μΩ・cm] at 1200 [℃] (Hiroki:
``Vacuum evaporation'' (Nikkan Kogyo Shimbun, 1972), which has the advantage of simplifying the structure of the recovery device by using the recovery plate itself as a heating element.

The explanation so far has been about a uranium isotope recovery device as an example, but there are other
It can be similarly applied to an isotope element recovery device.

As described above, the present invention provides an isotope element recovery device that enables continuous recovery and reduces maintenance time by providing a recovery plate heated to a temperature higher than the melting temperature of the isotope element.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 shows an example of the basic configuration of a uranium isotope separation/recovery device. The photons oscillated in a pulse form from the laser oscillator 1 are transmitted by the dye laser 2.
After being tuned to the excitation level wavelength of U ²³⁵ , it is introduced into the container through the transmission window 5 of the container 4 via the path changing mirror 3 . Here, the half mirror 6 and the mirror 7 are provided to reflect and reciprocate the photons inside the container in order to efficiently absorb the photons into the U ²³⁵ . A uranium vapor generator 8 is installed inside the vessel 4 to generate a mixed vapor stream 9 of U ²³⁵ and U ²³⁸ . The mixed vapor flow 9 is irradiated with laser light to excite and ionize U ²³⁵ .

Figure 2 shows the excitation and ionization process of uranium isotopes. The following description will be made using the one-wavelength two-step method as an example.

(Step 1: Excitation) The first photon a is absorbed and excited from the ground level to the excited level.

(Step 2: Ionization) The second photon a' is absorbed and ionized beyond the ionization level.

According to this method, U ²³⁵ can be excited above the ionization level (energy about 6.2 eV) with two photons.

Next, a method for separating ionized U ²³⁵ and unexcited U ²³⁹ will be explained with reference to FIG.

Even after laser beam irradiation, ionized U ²³⁵ and unexcited U ²³⁸ rise as a mixed vapor flow. At the top of the mixed vapor flow 9, when a magnetic field 10 is applied in a direction perpendicular to the mixed vapor flow 9, a force 11 acts to accelerate the ionized U ²³⁵ according to Fleming's law. Here, a collection plate 12 for collecting U ²³⁵ is installed above the mixed vapor flow 9.
By disposing a recovery plate 13 for collecting U ²³⁸ , uranium isotope elements can be selectively separated and recovered.

FIG. 3 shows a cross-sectional structure of a collection plate with adjacent heating elements. A heater 14 is installed at the back of the recovery plates 12 and 13 to radiantly heat the recovery plates. On the other hand, on the opposite side of the recovery plate to the heater 14, there is a reflecting plate 1 to reduce heat dissipation.
5 are stacked and installed. In addition, the collection plates 12, 13
A spacer 16 having heat resistance and insulation is appropriately arranged between the heater 14 and the reflection plate 15 to reduce electrical leakage and heat conduction. Power is supplied to the heater through a cable 17 connected to the end of the heater 14. In the embodiment shown in FIG. 3, a thermocouple 18 and a temperature control device 21 are provided to measure the heating temperature of the collection plate and control the heater temperature.

According to the embodiment of FIG. 3, the U ²³⁵ vapor flow adheres to the recovery plate 12, but the recovery plate 12 is
If preheated at step 4 to 1405 [〓] or higher, U ²³⁵
liquefies and aggregates. If the inclination angle of the collection plate is appropriately selected, the droplets 19 of U ²³⁵ will remain attached to the collection plate and will flow down and be collected at the bottom.If a collection container 20 is provided below the bottom, U ²³⁵ can be selectively separated and recovered, making continuous recovery possible. The collection plate 13 to which U ²³⁸ vapor adheres can also be continuously collected using a similar structure.

FIG. 4 shows a modification of the invention. This example is an example in which the collection plate itself is used as a heater. Since high-melting point metals have a specific resistance as shown above near the operating temperature of the recovery plate, the recovery plate itself can be formed as a heating element, and the heater shown in the embodiment shown in FIG. 3 may not be installed separately. This simplifies the structure.

In the above embodiments, a case has been described in which the collection plate is fixed in an inclined or vertical position, but a mechanism for rotating the collection plate may be provided to optimally set the inclination angle.

Further, the surface of the recovery plate is not limited to a flat surface, but may be a curved surface so as to form the line of fastest descent in relation to the inclination angle, for example.

〔Effect of the invention〕

According to the present invention, isotopic metals can be continuously recovered in a molten state, so the time for cleaning the recovery plate is reduced, and efficient separation and recovery, which is of great interest in industry, becomes possible. Furthermore, since the recovery system has a simple structure, it has the effect of facilitating mass production of the recovery system itself.

[Brief explanation of the drawing]

Figure 1 is a diagram showing an example of the basic configuration of the uranium isotope separation and recovery device according to the present invention, Figure 2 is a diagram showing the excitation and ionization process of uranium isotope elements, and Figure 3 is a diagram showing the excitation and ionization process of uranium isotope elements.
The figure shows an embodiment equipped with a collection plate of the present invention.
FIG. 4 is a diagram showing another embodiment in which the recovery plate itself is used as a heater. 1... Laser oscillator, 2... Dye laser, 3...
...Route change mirror, 4...Container, 5...Transparent window,
6...Half mirror, 7...Mirror, 8...Uranium steam generator, 9...Mixed vapor flow, 10...Magnetic field, 11...Acceleration force, 12...U ²³⁵ collection recovery plate, 13... ...U ²³⁸ Collection plate for collection, 14 ... Heater, 15 ... Reflection plate, 16 ... Spacer, 17
... Cable, 18 ... Thermocouple, 19 ... Isotope metal droplet, 20 ... Collection container, 21 ... Temperature control device.

Claims (1)

[Scope of Claims] 1. An evaporator that evaporates a substance containing two or more isotopic elements, and an evaporator that evaporates a substance containing two or more isotopic elements, and an evaporator capable of imparting energy that is half or more of the ionization energy to a specific isotopic element in the vapor atmosphere of the substance. In the isotope recovery device, which consists of a laser device that generates photons with ionized isotopes and a recovery device that collects the ionized isotope by applying a magnetic field, the separated substance is heated above its melting point in order to adhere. An isotope element recovery device characterized by being provided with a recovery plate. 2. An isotope element recovery device according to claim 1, characterized in that a heating element as a heating source is mounted in close proximity to the recovery plate to which the substance is attached. 3. The isotope element recovery device according to claim 1, wherein the recovery plate to which the substance is attached is itself a heating element as a heating source. 4. An isotope element recovery device according to any one of the above claims, characterized in that the recovery plate is installed in an inclined or vertical position, and the substance adhering to the surface is allowed to flow down and recovered. 5. The isotope element recovery device according to claim 4, characterized in that it is provided with a mechanism that makes the inclination angle of the recovery plate variable.