Decontamination of Tritiated Water

Patent metadata

Field	Value
Publication number	US-2016284433-A1
Application number	US-201315034611-A
Country	US
Kind code	A1
Filing date	Nov 13, 2013
Priority date	Nov 13, 2013
Publication date	Sep 29, 2016
Grant date	—

Abstract

Methods and systems directed to the separation of tritium from an aqueous stream are described. The separation method is a multi-stage method that includes a first stage during which tritium of a tritium-contaminated aqueous stream is adsorbed onto a separation phase, a second stage during which the adsorbed tritium is exchanged with hydrogen in a gaseous stream to provide a gaseous stream with a high tritium concentration, and a third stage during which the tritium of the gaseous stream is separated from the gaseous stream as a gaseous tritium product.

First claim

1 . A process for removal and recovery of tritium from tritium-contaminated water, the process comprising:
contacting a separation phase with an aqueous stream, the aqueous stream comprising tritium, the separation phase having an isotopic separation factor of about 1.06 or greater, the tritium being preferentially adsorbed onto the surface of the separation phase to form a purified aqueous stream; subsequently, contacting the separation phase with a gaseous stream, the gaseous stream comprising protium and/or deuterium in the form of hydrogen gas, deuterium gas, hydrogen deuteride, or mixtures thereof, the tritium that is adsorbed onto the surface of the separation phase being exchanged with the protium and/or the deuterium of the gaseous stream to form a tritium-enriched gaseous stream; and separating the tritium from the tritium-enriched gaseous stream.

2 . The process of claim 1 , wherein the separation phase comprises at least one of hydroxyl groups, water molecules, and a catalyst.

3 . The process of claim 1 , wherein the tritium is recovered from the tritium-enriched gaseous stream according to a thermal cycling adsorption process.

4 . The process of claim 1 , wherein the separation phase contacts about 500 tons per day or greater of the aqueous stream.

5 . The process of claim 1 , wherein the aqueous stream comprises the tritium in a concentration of about 1 part per billion or less.

6 . The process of claim 1 , further comprising pre-treating the aqueous stream.

7 . The process of claim 1 , wherein the separation phase comprises a solid or a gel or a particle.

8 . The process of claim 1 , wherein the purified aqueous stream has a radioactivity level from tritium of about 60,000 Becquerel per milliliter or less.

9 . The process of any claim 1 , wherein the gaseous stream is preheated to a temperature of from about 50° C. to about 373° C. and/or is at a pressure of from 0 to about 218 atm.

10 . The process of claim 1 , wherein the tritium-enriched gaseous stream comprises tritium in an amount of about 50 parts per million or greater.

11 . A system for removal and recovery of tritium from a tritium-contaminated aqueous stream, the system comprising:
an enrichment column containing a separation phase, the enrichment column including a liquid inlet at a first end of the enrichment column for receiving the tritium-contaminated aqueous stream and a liquid outlet at a second end of the enrichment column for exit of a clean aqueous stream, the enrichment column further comprising a gaseous inlet at the second end of the enrichment column for receiving a gaseous flow that includes protium and/or deuterium in the form of hydrogen gas, deuterium gas, hydrogen deuteride gas, or mixtures thereof, and a gaseous outlet at the first end of the enrichment column for exit of a tritium-enriched gaseous flow; and a thermal cycling adsorption column in fluid communication with the enrichment column, wherein the thermal cycling adsorption column is an inverse separation column and includes a separation material that preferentially adsorbs tritium at an adsorption temperature and that releases the adsorbed tritium at a release temperature.

12 . The system of claim 11 , further comprising one or more additional thermal cycling adsorption columns in fluid communication with the first thermal cycling adsorption column, wherein the additional thermal cycling adsorption column(s) include a second separation material that preferentially adsorbs protium over deuterium and over tritium at an adsorption temperature.

13 . The system of claim 11 , wherein the enrichment column has an inside diameter of about 5 feet or greater and a height of about 50 feet or greater.

14 . The system of claim 11 , further comprising a second enrichment column in fluid communication with the thermal cycling adsorption column.

15 . The process of claim 1 , the separation phase having an isotopic separation factor of about 1.1 or greater.

16 . The process of claim 2 , the catalyst comprising platinum.

17 . The process of claim 2 , the catalyst encouraging the transfer of the tritium from the separation phase to the gaseous stream.

18 . The process of claim 6 , wherein the pre-treatment comprises de-ionizing the aqueous stream.

19 . The process of claim 1 , wherein the separation phase is porous.

20 . The process of claim 19 , wherein the porous separation phase has an average pore diameter of about 500 Angstroms or less.

21 . The process of claim 1 , wherein the separation phase comprises a surface area of about 100 square meters per gram or greater.

22 . The process of claim 1 , wherein the separation phase comprises a polymeric material, an alumina, a silica, an aluminum silicate, or a silica gel.

Assignees

• Savannah River Nuclear Solutions Llc

Inventors

• Xiao Xin

Classifications

• B01D59/28

  Separation by chemical exchange · CPC title

• G21F9/301

  by fixation in stable solid media · CPC title

• G21F9/12 Primary

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

• C02F1/285

  using synthetic organic sorbents · CPC title

• B01D53/0462

  Temperature swing adsorption · CPC title