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USH800H - Method for gettering organic, inorganic and elemental iodine in aqueous solutions - Google Patents

Method for gettering organic, inorganic and elemental iodine in aqueous solutions Download PDF

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Publication number
USH800H
USH800H US07/341,005 US34100589A USH800H US H800 H USH800 H US H800H US 34100589 A US34100589 A US 34100589A US H800 H USH800 H US H800H
Authority
US
United States
Prior art keywords
iodine
organic
gettering
aqueous solutions
sub
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US07/341,005
Inventor
Edward C. Beahm
William E. Shockley
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
US Department of Energy
Original Assignee
US Department of Energy
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by US Department of Energy filed Critical US Department of Energy
Priority to US07/341,005 priority Critical patent/USH800H/en
Assigned to UNITED STATES OF AMERICA, THE, AS REPRESENTED BY THE DEPARTMENT OF ENERGY reassignment UNITED STATES OF AMERICA, THE, AS REPRESENTED BY THE DEPARTMENT OF ENERGY ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: BEAHM, EDWARD C., SHOCKLEY, WILLIAM E.
Application granted granted Critical
Publication of USH800H publication Critical patent/USH800H/en
Abandoned legal-status Critical Current

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Classifications

    • GPHYSICS
    • G21NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21FPROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
    • G21F9/00Treating radioactively contaminated material; Decontamination arrangements therefor
    • G21F9/02Treating gases
    • GPHYSICS
    • G21NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21FPROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
    • G21F9/00Treating radioactively contaminated material; Decontamination arrangements therefor
    • G21F9/04Treating liquids
    • G21F9/06Processing
    • G21F9/12Processing by absorption; by adsorption; by ion-exchange

Definitions

  • the invention was developed pursuant to a contract with the United States Department of Energy.
  • This invention relates to the removal of iodine from aqueous solutions, particularly the trapping of radioactive iodine to mitigate damage resulting from accidents or spills associated with nuclear reactors.
  • the subject invention relates to methods for removing iodine, particularly molecular I 2 and organic iodide compounds, from water pools.
  • iodine particularly molecular I 2 and organic iodide compounds
  • a principal area of need for this technology is the nuclear reactor industry where it is important to restrict release of radioactive iodine which can occur in accident situations or from mishandling during normal operations.
  • iodine-containing water pools will be present in the containment structure. Controlling the release of the iodine from the water pools will be a significant factor in the mitigation of damage.
  • the most troublesome of this class of compounds are the organic iodides for which no easy method of removal is presently available.
  • An additional object of this invention is to provide a process for cleaning spills in the event of a nuclear reactor accident.
  • the process of this invention may comprise removing iodine and iodide compounds from aqueous solution by exposing the solution to well dispersed silver carbonate which reacts with the iodine and iodides, thereby gettering iodine and iodine compounds from solution.
  • the invention is based on the discovery that silver carbonate well dispersed in water converts virtually all iodine including elemental iodine, inorganic iodides and organic iodides into a nonvolatile form. Elemental iodine and organic iodides are chemical forms of iodine that can volatilize from water pools. In severe nuclear reactor accidents, water pools would contain boric acid and would be irradiated from fission products and fuel debris. This invention has been shown to be effective in both irradiated and unirradiated water pools and also in water pools with or without boric acid.
  • I 2 may be treated ar a lower concentration of 1 ⁇ 10 -4 mol/L, but conversion of organic iodide is increased when a concentration of 1 ⁇ 10 -3 mol/L is used.
  • Dispersal of silver carbonate can be accomplished by placing the material in water in an ultrasonic system and then adding the resulting slurry into the water pool. This not only getters dissolved iodine and iodides by compound formation and precipitation, it also getters volatile iodine and iodides as well.
  • the present invention provides the buffer for pH control, the ability to remove both I 2 l and organic iodide, effectiveness under irradiation, and removal of iodine with a solid that is unmatched by alternative methods.
  • the next best technique known to the applicants is a combination of a reducing agent such as thiosulfate or hydrazine with a pH buffer such as a borate.
  • a reducing agent such as thiosulfate or hydrazine
  • a pH buffer such as a borate
  • the process is one for removing iodine form solution, it could be used as a method of separating fission products in a waste stream while maintaining low volatility.
  • the invention could be used to remove iodine leaving cesium ions which could then be treated by cation exchange. Because of the very low solubility product of silver iodide, this invention also is very effective at removing inorganic iodides from solution.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Solid-Sorbent Or Filter-Aiding Compositions (AREA)

Abstract

A process for the removal of iodine from aqueous solutions, particularly the trapping of radioactive iodine to mitigate damage resulting from accidents or spills associated with nuclear reactors, by exposing the solution to well dispersed silver carbonate which reacts with the iodine and iodides, thereby gettering iodine and iodine compounds from solution. The iodine is not only removed from solution but also from the contiguous vapor.

Description

The invention was developed pursuant to a contract with the United States Department of Energy.
This invention relates to the removal of iodine from aqueous solutions, particularly the trapping of radioactive iodine to mitigate damage resulting from accidents or spills associated with nuclear reactors.
BACKGROUND OF THE INVENTION
The subject invention relates to methods for removing iodine, particularly molecular I2 and organic iodide compounds, from water pools. A principal area of need for this technology is the nuclear reactor industry where it is important to restrict release of radioactive iodine which can occur in accident situations or from mishandling during normal operations. In severe nuclear reactor accidents, iodine-containing water pools will be present in the containment structure. Controlling the release of the iodine from the water pools will be a significant factor in the mitigation of damage. The most troublesome of this class of compounds are the organic iodides for which no easy method of removal is presently available.
A wide range of chemicals has been studied at Oak Ridge National Laboratory for effective removal of organic iodides from aqueous solution. One of the best reagents for this purpose is sodium thiosulfate which reacts with organic iodides as well as I2 and I-. Unfortunately sodium thiosulfate is not stable in radioactive environments. Therefore, there is a need for a reagent that can remove the radioactive species of organic iodides as well as I2 and I- from aqueous solution.
SUMMARY OF THE INVENTION
In view of the above needs, it is an object of this invention to provide a process for removing iodine from aqueous streams.
It is another object of this invention to provide a process for removing organic and inorganic iodides from radioactive aqueous streams.
An additional object of this invention is to provide a process for cleaning spills in the event of a nuclear reactor accident.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities an combinations particularly pointed out in the appended claims.
To achieve the foregoing and other objects and in accordance with the purpose of the present invention, as embodied and broadly described herein, the process of this invention may comprise removing iodine and iodide compounds from aqueous solution by exposing the solution to well dispersed silver carbonate which reacts with the iodine and iodides, thereby gettering iodine and iodine compounds from solution. This is an improvement over prior methods that were inappropriate for use in radiation environments.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The invention is based on the discovery that silver carbonate well dispersed in water converts virtually all iodine including elemental iodine, inorganic iodides and organic iodides into a nonvolatile form. Elemental iodine and organic iodides are chemical forms of iodine that can volatilize from water pools. In severe nuclear reactor accidents, water pools would contain boric acid and would be irradiated from fission products and fuel debris. This invention has been shown to be effective in both irradiated and unirradiated water pools and also in water pools with or without boric acid.
In order to practice the invention, it is only necessary to introduce well dispersed silver carbonate into the iodine containing water so that the overall amount, both dissolved and undissolved, is 1×10-3 mol/L. I2 may be treated ar a lower concentration of 1×10-4 mol/L, but conversion of organic iodide is increased when a concentration of 1×10-3 mol/L is used.
Dispersal of silver carbonate can be accomplished by placing the material in water in an ultrasonic system and then adding the resulting slurry into the water pool. This not only getters dissolved iodine and iodides by compound formation and precipitation, it also getters volatile iodine and iodides as well.
Example
The effectiveness of this iodine retaining process has been demonstrated in tests in an open system of aqueous solution and air where air was removed and stripped of iodine at a rate that resulted in replacement of the air volume in one hour. Results of these tests are given in the Table.
______________________________________                                    
OPEN SYSTEM TESTS                                                         
Room temperature   Ag.sub.2 CO.sub.3 :1 × 10.sup.-3                 
______________________________________                                    
I.sub.2 control (initially 5 × 10.sup.-5 mol/L I.sub.2)             
Without treatment                                                         
               None    27             138                                 
               None    32             309                                 
With Ag.sub.2 CO.sub.3 treatment                                          
               98      None detected <0.002                               
                                       72                                 
0.05 M o-boric acid with                                                  
               >99     0.002           72                                 
Ag.sub.2 CO.sub.3 treatment                                               
γ irradiated (0.45 Mrad/h)                                          
               95      2               29                                 
with Ag.sub.2 CO.sub.3 treatment                                          
Organic iodide control (initially 1 × 10.sup.-4 mol/L CH.sub.3 I)   
Without treatment                                                         
               None    56              66                                 
               None    58             186                                 
With Ag.sub.2 CO.sub.3 treatment                                          
               95       5             141                                 
γ irradiated (0.45 Mrad/h)                                          
               93       7              29                                 
with Ag.sub.2 CO.sub.3 treatment                                          
______________________________________                                    
In all the tests that employed Ag2 CO3, more than 90% of the initial iodine was associated with dispersed or settled solids. These solids can easily be removed by filtration. Also, there was a large reduction in the percentage of the initial iodine that volatilized. Thus, this invention provides for both control of volatility and for removal of iodine from water pools.
the present invention provides the buffer for pH control, the ability to remove both I2 l and organic iodide, effectiveness under irradiation, and removal of iodine with a solid that is unmatched by alternative methods. The next best technique known to the applicants is a combination of a reducing agent such as thiosulfate or hydrazine with a pH buffer such as a borate. However, this would not be stable under irradiation, and the reducing agents are subject to depletion by atmospheric oxidation. In addition, such a technique would not permit removal with solids.
Since the process is one for removing iodine form solution, it could be used as a method of separating fission products in a waste stream while maintaining low volatility. For example, the invention could be used to remove iodine leaving cesium ions which could then be treated by cation exchange. Because of the very low solubility product of silver iodide, this invention also is very effective at removing inorganic iodides from solution.

Claims (1)

We claim:
1. A process for removing iodine, from aqueous solution and from vapor contiguous thereto comprising exposing an iodine-containing solution to well dispersed silver carbonate which reacts with said iodine, thereby gettering said iodine from solutio and contiguous vapor.
US07/341,005 1989-04-20 1989-04-20 Method for gettering organic, inorganic and elemental iodine in aqueous solutions Abandoned USH800H (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US07/341,005 USH800H (en) 1989-04-20 1989-04-20 Method for gettering organic, inorganic and elemental iodine in aqueous solutions

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US07/341,005 USH800H (en) 1989-04-20 1989-04-20 Method for gettering organic, inorganic and elemental iodine in aqueous solutions

Publications (1)

Publication Number Publication Date
USH800H true USH800H (en) 1990-07-03

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Family Applications (1)

Application Number Title Priority Date Filing Date
US07/341,005 Abandoned USH800H (en) 1989-04-20 1989-04-20 Method for gettering organic, inorganic and elemental iodine in aqueous solutions

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070223645A1 (en) * 2004-05-19 2007-09-27 Wilfried Ruehle Bonding Radioactive Iodine in a Nuclear Reactor
CN102371192A (en) * 2010-08-23 2012-03-14 中国石油化工股份有限公司 Preparation method of deiodination agent

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3865688A (en) 1970-08-05 1975-02-11 Frank W Kleimola Passive containment system
US3896042A (en) 1974-02-15 1975-07-22 Us Energy Low temperature, low pressure hydrogen gettering
US3898125A (en) 1971-12-08 1975-08-05 Gen Electric Nuclear fuel element containing strips of an alloyed Zr, Ti and Ni getter material
US3899392A (en) 1971-12-08 1975-08-12 Gen Electric Nuclear fuel element containing particles of an alloyed Zr, Ti and Ni getter material
US3969185A (en) 1973-05-09 1976-07-13 General Electric Company Getter for nuclear fuel elements

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3865688A (en) 1970-08-05 1975-02-11 Frank W Kleimola Passive containment system
US3898125A (en) 1971-12-08 1975-08-05 Gen Electric Nuclear fuel element containing strips of an alloyed Zr, Ti and Ni getter material
US3899392A (en) 1971-12-08 1975-08-12 Gen Electric Nuclear fuel element containing particles of an alloyed Zr, Ti and Ni getter material
US3969185A (en) 1973-05-09 1976-07-13 General Electric Company Getter for nuclear fuel elements
US3896042A (en) 1974-02-15 1975-07-22 Us Energy Low temperature, low pressure hydrogen gettering

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070223645A1 (en) * 2004-05-19 2007-09-27 Wilfried Ruehle Bonding Radioactive Iodine in a Nuclear Reactor
DE102004024722B4 (en) * 2004-05-19 2011-05-26 Enbw Kraftwerke Ag Kernkraftwerk Philippsburg Binding of radioactive iodine in a nuclear reactor
CN102371192A (en) * 2010-08-23 2012-03-14 中国石油化工股份有限公司 Preparation method of deiodination agent
CN102371192B (en) * 2010-08-23 2013-04-03 中国石油化工股份有限公司 Preparation method of deiodination agent

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Owner name: UNITED STATES OF AMERICA, THE, AS REPRESENTED BY T

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:BEAHM, EDWARD C.;SHOCKLEY, WILLIAM E.;REEL/FRAME:005125/0232

Effective date: 19890403

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