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United States Patent [w]
[li] 4,096,046  Jun. 20, 1978
 METHOD AND APPARATUS FOR THE SEPARATION OR ENRICHMENT OF ISOTOPES
 Inventor: Hans-Joachim Niemann, Erlangen, Germany
 Assignee: Kraftwerk Union Aktiengesellschaft, Mulheim (Ruhr), Germany
 Appl. No.: 676,490
 Filed: Apr. 13, 1976
 Foreign Application Priority Data
Apr. 22, 1975 Germany 2517828
 Int. CI.* B01J 1/10
 U.S. a 204/157.1 R; 204/163 R;
250/527; 204/DIG. 11
 Field of Search 204/157.1 R, DIG. 11;
 References Cited
U.S. PATENT DOCUMENTS
3,443,087 5/1969 Robieux et al 204/157.1 R
3,719,454 3/1973 Shang 204/DIG. 11
3,937,956 2/1976 Lyon 250/290
IBM Technical Disclosure Bulletin, vol. 17, No. 11 (April 1975) pp. 3501 & 3502.
Primary Examiner—Howard S. Williams
Attorney, Agent, or Firm—Herbert L. Lerner
Method for separation or enrichment of isotopes bound to anisotopic materials and forming a mixture of isotope compounds by irradiating the mixture of isotope compounds with a first light source to photochemically convert the mixture to a second mixture of isotope compounds, e.g. converting UF6to UF5and F, irradiating the second mixture in the presence of a reactant with a second light source to selectively excite only one isotope compound of the second mixture, the reactant chemically reacting with the excited compound, e.g. UF5^-UF4 + F or UF5 + R ... + RF and separating the reaction products including one of the isotopes of the first mixture.
The separation or enrichment of isotopes may be carried out in apparatus having a highly-reflecting elliptical cylinder with a reaction vessel provided with feed and reactant inlet and reaction products outlet, disposed at one focal line of the elliptical cylinder and a high pressure mercury burner disposed at the second focal line, and with the reaction vessel arranged between resonator mirrors of a dye laser as the second light source.
12 Claims, 4 Drawing Figures
U. S. Patent June 20, 1978 Sheet 1 of2 4,096,046
METHOD AND APPARATUS FOR THE SEPARATION OR ENRICHMENT OF ISOTOPES
CROSS-REFERENCES TO RELATED
In my co-filed U.S. application Ser. No. 676,461, entitled "Method of Separating Isotopes", is disclosed separation of isotopes from a mixture of respective compounds particularly UF6 compounds, involving passing laser radiation having a spectral width maximally corresponding to the width of the isotope shift, through a vaporous mixture of the compounds.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a method and apparatus for the separation or enrichment, with the aid of high-intensity light source, such as lasers, especially, of isotopes which are bound to single-isotope substances and which form therewith a mixture of compounds.
2. Description of the Prior Art
The use of such high-intensity light sources for the separation of isotopes has previously been proposed, for example, in German Published Prosecuted Applications DT-OS No. 1,959,767 and DT-OS No. 2,150,232. The proposals for uranium enrichment contained therein start with uranium hexafluoride, which has a particularly high vapor pressure. By selective excitation of the U235F6 compound, for example, by means of laser light of a frequency which corresponds to a known rotation vibration line of this isotope compound, selective excitation is achieved in such a manner that these excited molecules react with a suitable reaction partner to form another compound. The new compound can then be taken from the mixture of the starting materials by chemical or chemical-physical means. Since the frequency shift between the rotation vibration lines of the uranium isotope compounds is relatively small and there are very many rotation vibration lines, it is difficult to find particularly well suited frequencies.
It is also possible to consider uranium compounds for their suitability with respect to isotope separation by laser beams. For example, it has previously been proposed to use UC16 or UF5C1 for this purpose. These compounds, however, have further inherent problems, as the elements bound to the uranium are in themselves not single-isotope elements, i.e., not anisotopic elements. Since there elements possess several isotopes, there are additional rotation lines, which further add to the above mentioned difficulties.
It has therefore been proposed to overcome these difficulties by another starting compound of uranium, which meets the following requirements:
1. it must be gaseous,
2. in addition to uranium, it must contain only such atoms which do not occur in nature as different isotopes, and therefore are single-isotope elements, i.e. anisotopic elements, and
3. the optical absorption spectrum must be such that at least one wavelength is absorbed by one of the two possible uranium compounds predominantly or exclusively.
One suitable uranium compound has now been found to be uranium pentafluoride UF5 which, like UF6, contains only an anisotopic element, besides uranium. However, it has the great disadvantage that it has practically no vapor pressure at room temperature.
SUMMARY OF THE INVENTION
An object of the invention is to provide a method and apparatus for the separation or enrichment of isotopes
5 which are bound to anisotopic elements and form with the latter a mixture of isotope compounds by subjecting the mixture of isotope compounds to a first light source and then to a second light source. With the foregoing and other objects in view there is
1° provided in accordance with the invention, a method for the separation or enrichment of isotopes which are bound to anisotopic substances and form with the latter a mixture of isotope compounds which comprises the following steps:
*5 a. irradiating said mixture of compounds in gas or vapor form by a first light source to photochemically convert the isotope compounds to another mixture of isotope compounds, b. irradiating said photochemically converted mix
20 ture of isotope compounds by a second light source, at a frequency to selectively excite only one compound of said photochemically converted mixture of isotope compounds,
25 c. effecting said excitation in the presence of a reactant which chemically reacts with the excited compound of the mixture to produce a reaction product, and d. separating the reaction products, enriched with one of the starting isotopes.
j0 In accordance with the invention there is provided apparatus for the separation or enrichment of isotopes which are bound to anisotopic substances and form with the latter a mixture of isotope compounds, which comprises a highly-reflecting elliptical cylinder, a tubular
35 irradiation and reaction vessel disposed at one focal line of said reflecting elliptical cylinder, a high pressure mercury burner as a first light source disposed at the second focal line of said reflecting elliptical cylinder, resonator mirrors of a dye laser as a second light source
40 disposed to irradiate a mixture of isotope compounds in said reaction vessel, an inlet to said reaction vessel for introducing a feed mixture of isotope compounds, an inlet to said reaction vessel for introduction of a reactant, and an outlet for said reaction vessel for the dis
45 charge of reaction products.
In a further embodiment in accordance with the invention there is provided apparatus for the separation or enrichment of isotopes which are bound to anisotopic substances and form with the latter a mixture of
50 isotope compounds, which comprises a tubular irradiation and reaction vessel, an inlet to said reaction vessel for introducing a feed mixture of isotope compounds, an inlet to said reaction vessel for introduction of a reactant, an outlet for said reaction vessel for the discharge
55 of reaction products, a laser as a first light source with said light directed through said reaction vessel in the axial direction of the vessel, said first light having a frequency at which only the feed material is excited without exciting the resultant reaction product, and
60 resonator mirrors of a dye laser as a second light source disposed to irradiate, in an axial direction through said reaction vessel, the reaction product produced by irradiation from said first light source. In accordance with the invention, the compound, e.g.
65 UF5, is formed during the irradiation process and is selectively excited and chemically converted before condensation comes about. The method of the invention has the following steps: