Method for reducing HTO concentration in aqueous solution

Patent metadata

Field	Value
Publication number	US-11446608-B2
Application number	US-201816617935-A
Country	US
Kind code	B2
Filing date	May 29, 2018
Priority date	May 29, 2017
Publication date	Sep 20, 2022
Grant date	Sep 20, 2022

Abstract

The present invention relates to a method for reducing the HTO concentration in a tritium-containing aqueous solution. The present invention includes bringing water vapor or the like of a tritium-containing aqueous solution into contact with a porous material having pores in a pore diameter range of 500 Å or less, selectively occluding the HTO in the tritium-containing aqueous solution in the porous material, and obtaining a tritium-containing aqueous solution in which the HTO concentration thereof is reduced. The present invention relates to a device used for reducing the HTO concentration in a tritium-containing aqueous solution. The present invention includes a reservoir for a raw tritium-containing aqueous solution, a means for generating water vapor or the like of the tritium-containing aqueous solution, an occlusion means in which is accommodated a porous material having pores in a pore diameter range of 500 Å or less, and a means for recovering the tritium-containing aqueous solution in which the HTO concentration is reduced. The present invention furthermore includes a transfer means for transferring the water vapor or the like to the occlusion means, and a means for transferring the tritium-containing aqueous solution in which the HTO concentration is reduced from the occlusion means to a recovery means.

First claim

The invention claimed is:

1. A method of reducing HTO concentration in a tritium (HTO)-containing aqueous solution, the method comprising:
continuously or intermittently bringing water vapor and/or mist of a HTO-containing aqueous solution into contact with a porous body having pores with a pore diameter within the range of 500 Å or less to allow HTO in the HTO-containing aqueous solution to be selectively occluded in the porous body, and obtaining an unoccluded liquid as a HTO-containing aqueous solution reduced in HTO concentration, which will be hereinafter referred to as low-HTO-content water, wherein water vapor or mist of the HTO-containing aqueous solution is brought into contact with the porous body while the porous body is held at a temperature of 30° C. or higher.

2. The method according to claim 1 , wherein the porous body has at least a pore with a pore diameter falling within the range of more than 4 Å and 25 Å or less or the porous body has a specific surface area ranging from 5 to 250 m 2 /g.

3. The method according to claim 1 , wherein the porous body is an inorganic material porous body.

4. The method according to claim 3 , wherein the inorganic material porous body is a porous body containing at least one selected from the group consisting of zeolite, γ-alumina, silica gel, boehmite, and aluminum; or the inorganic material porous body is a porous body of aluminum having a boehmite coating; or the inorganic material porous body is a powder; or the inorganic material porous body is a powder sintered porous body.

5. The method according to claim 1 , wherein the porous body with which water vapor or mist of the HTO-containing aqueous solution is brought into contact is held at a temperature equal to or lower than an endothermic peak temperature in differential scanning calorimetry of HTO occluded in the pore of the porous body.

6. The method according to claim 5 , wherein the porous body has an endothermic peak temperature in differential scanning calorimetry of HTO occluded in the pore of the porous body falling within the range of 60° C. to 100° C.

7. The method according to claim 1 , wherein water vapor and/or mist of the HTO-containing aqueous solution is supplied under a pressure within the range of from atmospheric pressure to the saturated vapor pressure of the HTO-containing aqueous solution, and is brought into contact with the porous body, thereby allowing HTO to be selectively adsorbed on the porous body, and the HTO-containing aqueous solution reduced in HTO concentration (low-HTO-content water) is obtained by making the downstream side of the porous body more negative in pressure than the supplying side of the HTO-containing aqueous solution to allow preferential transpiration of light water from the porous body surface.

8. The method according to claim 1 , wherein the contact between the water vapor and/or mist of the HTO-containing aqueous solution and the porous body is performed under reduced pressure.

9. The method according to claim 1 , wherein the porous body comprises a plurality of porous bodies, and the method comprises that the water vapor and/or mist of the HTO-containing aqueous solution comes into sequential contact with the plurality of porous bodies; and a HTO concentration reduction rate of the HTO-containing aqueous solution reduced in HTO concentration obtained after contact with the porous body increases with an increase in number of the porous bodies.

10. The method according to claim 1 , the method further comprises collecting and storing the porous body occluding a prescribed amount of HTO or further comprises collecting a porous body occluding a prescribed amount of HTO and allowing the collected porous body to release the occluded HTO and collecting the released HTO.

11. The method according to claim 1 , wherein the contact of water vapor and/or mist of the HTO-containing aqueous solution with the porous body is performed at a pressure within the range of 10 3 to 10 5 Pa.

12. The method according to claim 1 , wherein a temperature of the porous body is at 100° C. or less when the contact of water vapor and/or mist of the HTO-containing aqueous solution with the porous body is performed.

Assignees

• Univ Kinki
• A Atom Technol Kindai
• Toyo Aluminium Kk

Inventors

• Ihara Tatsuhiko
• YAMANISHI Hirokuni
• Noma Hiroshi
• Taira Toshifumi
• HOSHIYA Takashi
• Fujimoto Kazuya

Classifications

• B01D59/26 Primary

  by sorption, i.e. absorption, adsorption, persorption · CPC title

• C02F1/281

  using inorganic sorbents · CPC title

• G21F9/12 Primary

  by absorption; by adsorption; by ion-exchange · CPC title

• B01J20/103

  comprising silica · CPC title

• B01J20/3204

  Inorganic carriers, supports or substrates · CPC title