Metal alloy treatment process for radioactive waste

• US 6,355,857 B1
• Filed: 06/17/1999
• Issued: 03/12/2002
• Est. Priority Date: 06/17/1999
• Status: Expired due to Term

• Current Assignee: Clean Technology International Corp.
• Original Assignee: Clean Technology International Corp.
• Inventors: Wagner, Anthony S.
• Primary Examiner(s): Griffin, Steven P.
• Assistant Examiner(s): NAVE, EILEEN ENAD
• Application Number:
  US09/334,985
• Time in Patent Office: 999 Days
• Field of Search: 588/1, 588/2, 588/15, 588/18, 588/20, 588/201, 588/249, 588/252, 588/261, 588/901, 205/505.1, 205/506.1, 205/507.1, 205/515.1, 205/518.1, 252/625, 376/277, 376/287, 376/288, 376/289, 376/290
• US Class Current: 588/15
• CPC Class Codes: G21F 9/06 Processing separating different isotopes of the same chemical element B01D59/00
• CPC Class Codes: G21F 9/30 Processing separating different isotopes of the same chemical element B01D59/00
• CPC Class Codes: G21F 9/302 in an inorganic matrix

Abstract

A waste treatment process includes containing a reactant metal alloy (210) in a reactant alloy container (202) substantially isolated from oxygen gas. The reactant metal alloy includes at least one chemically active alkaline metal and at least one radiation absorbing metal. After heating the reactant alloy (210) in the reactant alloy container (202) to a desired operating temperature, a waste material including radioactive isotopes to be alloyed is introduced into the molten alloy, preferably below the surface of the alloy. Non-radioactive compounds in the waste material react with metals in the reactant alloy (210) to produce useful halogen salts and other materials. The metal radioactive isotopes in the waste material are alloyed with the alkaline metal and radiation absorbing metals to create a storage product for long term storage.

Claims

1. A method for treating a waste material which includes at least one type of radioactive isotope to be alloyed with a reactant metal alloy, the method comprising the steps of:

(a) identifying each radioactive isotope which is present in the waste material at a detectable level and determining the concentration of each said radioactive isotope in the waste material;

(b) producing the reactant metal alloy for a selected volume of the waste material, the reactant metal alloy being held in a molten state and including at least one chemically active metal and, for each type of expected radioactive emission associated with the selected volume of the waste material, at least one corresponding radiation absorbing metal, each corresponding radiation absorbing metal being capable of absorbing the respective type of expected radioactive emission; and

(c) adding the selected volume of the waste material to the molten reactant metal alloy.

2. The method of claim 1 wherein the molten reactant metal alloy includes a sufficient quantity of each corresponding radiation absorbing metal so that, once the selected volume of waste material has been added to the molten reactant metal alloy, the molten reactant metal alloy includes a minimum ratio of atoms of each corresponding radiation absorbing metal to each expected radioactive emission within the volume of the molten reactant metal alloy, the minimum ratio being no less than seven hundred and twenty-seven (727) corresponding radiation absorbing atoms for each respective expected radioactive emission.

3. The method of claim 1 further comprising the step of:

(a) maintaining the amount of the chemically active metal in the molten reactant metal alloy at no less than forty percent of the total molten reactant metal alloy by weight.

4. The method of claim 1 further comprising the step of:

(a) maintaining the molten reactant metal alloy at an operating temperature of no less than 770 degrees Celsius as the waste material is added to the molten reactant metal alloy.

5. The method of claim 1 wherein each chemically active metal is selected from the group consisting of magnesium, aluminum, lithium, zinc, calcium, and copper.

6. The method of claim 1 further comprising the step of:

(a) monitoring radioactive emissions from a stream of the selected volume of waste material being directed to the molten reactant metal alloy to be added thereto, the monitoring providing an indication of the level of radioactive emissions from the stream of waste material; and

(b) halting the stream of waste material in response to an anomalous radioactive emission level detected from the stream of waste material.

7. A method for treating a waste material which includes at least one type of radioactive isotope to be alloyed with a reactant metal alloy, the method comprising the steps of:

(a) identifying each radioactive isotope which is present in the waste material at a detectable level and determining the amount of each said radioactive isotope in the waste material;

(b) producing the reactant metal alloy for a selected volume of the waste material, the reactant metal alloy being held in a molten state and including at least one chemically active metal and, for each type of expected radioactive emission associated with the selected volume of the waste material, at least one corresponding radiation absorbing metal, each corresponding radiation absorbing metal being capable of absorbing the respective type of expected radioactive emission; and

(c) adding the selected volume of the waste material to the molten reactant metal alloy.

8. The method of claim 7 wherein the molten reactant metal alloy includes a sufficient quantity of each corresponding radiation absorbing metal so that, once the selected volume of waste material has been added to the molten reactant metal alloy, the molten reactant metal alloy includes a minimum ratio of atoms of each corresponding radiation absorbing metal to each expected radioactive emission within the volume of the molten reactant metal alloy, the minimum ratio being no less than seven hundred and twenty-seven (727) corresponding radiation absorbing atoms for each respective expected radioactive emission.

9. The method of claim 7 further comprising the step of:

(a) maintaining the amount of the chemically active metal in the molten reactant metal alloy at no less than forty percent of the total molten reactant metal alloy by weight.

10. The method of claim 7 further comprising the step of:

(a) maintaining the molten reactant metal alloy at an operating temperature of no less than 770 degrees Celsius as the waste material is added to the molten reactant metal alloy.

11. The method of claim 7 wherein each chemically active metal is selected from the group consisting of magnesium, aluminum, lithium, zinc, calcium, and copper.

12. The method of claim 7 further comprising the step of:

(a) monitoring radioactive emissions from a stream of the selected volume of waste material being directed to the molten reactant metal alloy to be added thereto, the monitoring providing an indication of the level of radioactive emissions from the stream of waste material; and

(b) halting the stream of waste material in response to an anomalous radioactive emission level detected from the stream of waste material.