CA1071415A - Method for the recovery of halogens from sodium - Google Patents
Method for the recovery of halogens from sodiumInfo
- Publication number
- CA1071415A CA1071415A CA258,986A CA258986A CA1071415A CA 1071415 A CA1071415 A CA 1071415A CA 258986 A CA258986 A CA 258986A CA 1071415 A CA1071415 A CA 1071415A
- Authority
- CA
- Canada
- Prior art keywords
- sodium
- vessel
- iodine
- coolant
- segregation
- 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.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C17/00—Monitoring; Testing ; Maintaining
- G21C17/02—Devices or arrangements for monitoring coolant or moderator
- G21C17/04—Detecting burst slugs
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C19/00—Arrangements for treating, for handling, or for facilitating the handling of, fuel or other materials which are used within the reactor, e.g. within its pressure vessel
- G21C19/28—Arrangements for introducing fluent material into the reactor core; Arrangements for removing fluent material from the reactor core
- G21C19/30—Arrangements for introducing fluent material into the reactor core; Arrangements for removing fluent material from the reactor core with continuous purification of circulating fluent material, e.g. by extraction of fission products deterioration or corrosion products, impurities, e.g. by cold traps
- G21C19/307—Arrangements for introducing fluent material into the reactor core; Arrangements for removing fluent material from the reactor core with continuous purification of circulating fluent material, e.g. by extraction of fission products deterioration or corrosion products, impurities, e.g. by cold traps specially adapted for liquids
- G21C19/31—Arrangements for introducing fluent material into the reactor core; Arrangements for removing fluent material from the reactor core with continuous purification of circulating fluent material, e.g. by extraction of fission products deterioration or corrosion products, impurities, e.g. by cold traps specially adapted for liquids for molten metals
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- General Engineering & Computer Science (AREA)
- High Energy & Nuclear Physics (AREA)
- Monitoring And Testing Of Nuclear Reactors (AREA)
- Manufacture And Refinement Of Metals (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Iodine and bromine are easily and quantitatively sepa-rated from the coolant of sodium-cooled reactors by passing a quantity of the sodium into a metal segregation vessel, and reducing the temperature of the vessel and coolant, whereupon the iodine and bromine segregates and adheres to the inner surface of the vessel where they remain after the coolant is separated from the vessel. This method is useful for establishing the absence or the presence and possible severity of a failed fuel element in the reactor.
Iodine and bromine are easily and quantitatively sepa-rated from the coolant of sodium-cooled reactors by passing a quantity of the sodium into a metal segregation vessel, and reducing the temperature of the vessel and coolant, whereupon the iodine and bromine segregates and adheres to the inner surface of the vessel where they remain after the coolant is separated from the vessel. This method is useful for establishing the absence or the presence and possible severity of a failed fuel element in the reactor.
Description
1~7~
METHOD FOR THE RECOVERY OF H~JIOGEI~S FROM SODIUM
BACKGROUND O~ THE INVRNTION
This invention relates to a method for separating halogens from the coolant of a sodium-cooled nuclear reactor.
More specifically, this invention relates to an improvement in the method for detecting and obtaining information about the presence of failed fuel elements in a sodium-cooled nuclear reactor by the quantitative recovery of fission product iodine and bromine, which are indicative of the presence of a failed fuel element.
In sodium-cooled nuclear reactors, fuel element cladding failures are accompanied by the release of fission products to the liquid sodium coolant. These fission products are present in the form of gases and elemental or combined solids. The form and types of fission products - . . :
. , , . " ~ , , . .
which are released depend upon the type of fuel and fue~
cladding failure. The claddlng failure in the gas-containing plenum section of a fuel element may result only in the release of gaseous fission products such as xenon or krypton. Fission gas releases due to such plenum failures or "leakers" are not serious; however, a cladding failure wherein the sodium coolant enters the fuel element and con-tacts the fuel oxide may be serious if its progression is not monitored and the defective fuel element removed. In such failures the sodium coolant and oxide fuel may inter-act to cause swelling and weakening of the oxide structure, resulting in solid fission products being leached from the fuel by the sodium and released along with fission gases to the sodium coolant system. This type of failure can be tolerated to a certain extent. However~ the failure's pro-gression must be carefully monitored, for if it continues or increases in severity, the continued leaching can cause the disintegration of the fuel matrix and fuel particle washout through the cladding failure. Various techniques and procedures have been proposed and utilized in the past to detect fuel element failures. Techniques for monitoring the sodium cover gas to determine the total act:ivity of fission product gases have been successful in detecting fuel element failures. However~ these techniques have not proven entirely satisfactory due to their inability to dirferentiate between the decay activity of gaseous fission products released directly from plenum leakers and the gaseous daughter activity of dissolved fission products s~ :
(i.e. iodine and bromine) leached from the nuclear fuel during sodium contact with oxide fuel in the more serious fuel element failures. As a result, such monitoring tech-n:Lques have necessitated reactor shutdowns in the past merely from fisslon gas leaks in the fuel element plenum sections. Such shutdowns due to leakers are unnecessary, costly and result in significant loss of reactor avail-ability.
The halogens iodine and bromine are one class of fission products which are leached readily from oxide fuels by sodium. Normally, iodine and bromine would be gaseous at the temperature of the oxide fuel outer surface. However, in the oxide matrix fission product halogens may not exist in the elemental form because of chemical reactions. Halogens do not normally escape from failed fuel elements which are leaking only fission gases. So monitoring of halogen iso-topes in the sodium coolant would be desirable in order to monitor fuel element failures which are significant in terms of sodium-fuel oxide contact. Unfortunately, direct detection of halogen isotopes in the coolant by gamma ray analysis is impossible because of the presence of short-lived Na(tl/2 = 15 h~. Consequently, a rapid and efficient separation technique is necessary to isolate the radiohalogens for measurement.
SUMMARY OF THE INVENTION
We have discovered a new method for separating halogens from the sodium coolant of a nuclear reactor which is rela-tively simple and inexpensive and by which we are able to S ~ `
near quantitative recovery. Our method consists of passing a quantity of sodium at a temperature above 200C.
into a metal segregation vessel. The vessel and contained r sodium is then cooled to below 120C., w~lereby the halogens present in the sodium adhere to the wall of the segregation vessel. The cooled sodium is then separated from the vessel while the halogens remain on the wall of the vessel.
By recovering the halogens from the wall of the segre-gation vessel and determining their activity, particularly 10 131I, it is possible to determine the absence or presence and possible severity of a fuel element failure within the reactor.
It is therefore one object of the invention to provide an effective and inexpensive method for separating halogens from the coolant of a sodium-cooled nuclear reactor.
It is another object of the invention to provide an effective and inexpensive method for separating iodine and bromine from the coolant of a sodium-cooled nuclear reactor.
Finally, it is the object of the invention to provide 20 an improvement in the method for detecting the presence of a failed fuel element in a sodium-cooled reactor.
DETAILED DESCRIPTION OF THE INVENTION
These and other objects of the invention for the sepa-ration of iodine and bromine from the coo]ant of a sodium-cooled reactor may be met by passing a quantity of liquid sodium coolant at a temperature of above 200 C. into a stainless steel or titanium segregation vessel, cooling the vessel and the coolant to about 100-120 C. 3 whereby ~ 4 --the iodine and bromine in the sodium adhere to the wall of the vessel, and separating the cooled sodium from the vessel whlle the iodine and bromine remain on the wall, thereby separating the iodine and bromine from the coolant.
It is believed that the segregation of halogens will occur in a segregation vessel made of any metal which will withstand the high-temperature sodium environment. However, metals on which segregation of the halogens is known to occur are stainless steel and titanium.
The method of the invention is useful for the quanti- ;
tative recovery of halogens such as iodine and bromine and should be useful for the recovery of chlorine and fluorine. ~ -The process has also been found useful for the complete or partial recovery of other chemical elements which segregate from the coolant (i.e. tritium, antimony, zinc, tantalum and cesium), although the temperatures necessary for their recovery may vary.
The sodium content must be at least 200C. as it is passed into the segregation vessel in order to maintain the halogens and various other chemical elements in solution.
Generally, the temperature of the sodium coolant as it flows through a reactor is at least 350C. or higher. Once the liquid sodium has been passed into the segregation vessel, the vessel and the sodium coolant are cooled to a tempera-ture below 120C. or near the melting point of sodium for the fission products to migrate to and adhere to the sur-face of the segregation vessel. It is preferred that the coolarlt temperature be lowered to between 100-120 C. to 1~7~L4~5 obtain the best results for the recovery of the fission products from the coolant. The sodium may also be allowed to solidify and be removed later by heating to the melting temperature wlthout affecting the results. After the sodium has been cooled to the segregation temperature, it can be removed from the segregation vessel by any con-venient means such as by draining or by forcing out with an inert gas under pressure, while the halogen and other chemical elements will remain on the wall of the vessel.
The volume of liquid-metal-to-surface area of the segregation vessel has not been found to be critical, although it is preferred that the volume-to-surface ratio be as low as possible to provide the most favorable con-ditions for a quantitative recovery of the chemical ele-ments of interest. Volume-to-surface ratios up to about 2 have been shown to provide quantitative halogen recovery.
The halogens are then washed from the wall of the vessel and analyzed by accepted radiochemical methods.
The segregation vessel may be of any convenient size and shape, maintaining a low volume-to-surface area ratio in order to ensure quantitative recovery of halogens from the sodium. For example, the vessel may be a tube, a hollow cylinder or even a pot formed of an appropriate metal.
In the practical use of this invention for separating halogens present in the coolant of a nuclear reactor, a by-pass line containing a removable tube would be con-structed paralleling one of the main sodium-coolant flow 7~5 lines. A portion of the sodium is directed through the by-pass line, preferably in an upward direction to prevent the '~
collection of bubbles in the sodium which may cause a minor reductlon in efficiency on the recovery of the halogens.
When a determination for halogens is desired, the flow through the segregation vessel is stopped by valving off the by-pass line to isolate the segregation vessel. The segregation vessel would then be cooled to 100-120C. so that the halogens in the molten sodium will migrate and adhere to the inner walls of the segregation tube. The cooled sodium would then be forced out of the segregation tube with an inert gas such as argon and the tube removed from the system for analysis of radioactive halogens of interest. From the amount of radioactive iodine present in the tube, the iodine present in the total sodium cooling system can be ascertained.
In an alternative method for determining iodine con-tent, a few volumes of nonradioactive sodium at 100-120C.
could be passed through the segregation vessel to wash away any radioactive sodium-24 adhering to the walls of the segre-gation vessel. The vessel could be left in place and the amount of radioactive iodine present on the inner wall of the vessel could be counted with a lithium drifted germanium detector. This would prevent the necessity for removing the segregation tube from the by-pass line; however, it would be necessary to shield the detector from extraneous radio-activity and from thermal radiation. The activity of the segregated nuclides of interest can be determined by counting . , ~L~7~15 at calibrated geometries. The ~low of the 200C. primar~
coolant can then be directed through the segregation vessel to wash the radioactive iodine and other nuclides from the wall of the vessel and permit a new sample to be started.
,~tlll a further method for completing radioiodine analysis would be to seal the drained vessel in place and allow any short-lived radioiodines to decay to their daughter product xenons, reheat the vessel during a helium purge and concen-trate the evolved xenon daughters on activated charcoal for quantitative gamma-ray analysis of selected xenon isotope,.
The following examples are given as illustrative of the method of the invention and not to be taken as limiting the scope which shall be defined by the appended claims.
EXAMPLE I
A liter of molten sodium at 370C. contained in a ; stainless steel pot having a surface area of 237 square inches with a 13 I concentration of about 2.8 x 105 dis/min/ml was cooled to about 120C. The 131I concentra-tion in the bulk sodium was reduced by about 99% or to 20 about 0.03 x 105 dis/min/ml. In a further experiment using the same stainless steel pot, 200 square inches of york mesh was placed in the sodium which was then heated to 427C. The initial 13lI concentration in the sodium of
METHOD FOR THE RECOVERY OF H~JIOGEI~S FROM SODIUM
BACKGROUND O~ THE INVRNTION
This invention relates to a method for separating halogens from the coolant of a sodium-cooled nuclear reactor.
More specifically, this invention relates to an improvement in the method for detecting and obtaining information about the presence of failed fuel elements in a sodium-cooled nuclear reactor by the quantitative recovery of fission product iodine and bromine, which are indicative of the presence of a failed fuel element.
In sodium-cooled nuclear reactors, fuel element cladding failures are accompanied by the release of fission products to the liquid sodium coolant. These fission products are present in the form of gases and elemental or combined solids. The form and types of fission products - . . :
. , , . " ~ , , . .
which are released depend upon the type of fuel and fue~
cladding failure. The claddlng failure in the gas-containing plenum section of a fuel element may result only in the release of gaseous fission products such as xenon or krypton. Fission gas releases due to such plenum failures or "leakers" are not serious; however, a cladding failure wherein the sodium coolant enters the fuel element and con-tacts the fuel oxide may be serious if its progression is not monitored and the defective fuel element removed. In such failures the sodium coolant and oxide fuel may inter-act to cause swelling and weakening of the oxide structure, resulting in solid fission products being leached from the fuel by the sodium and released along with fission gases to the sodium coolant system. This type of failure can be tolerated to a certain extent. However~ the failure's pro-gression must be carefully monitored, for if it continues or increases in severity, the continued leaching can cause the disintegration of the fuel matrix and fuel particle washout through the cladding failure. Various techniques and procedures have been proposed and utilized in the past to detect fuel element failures. Techniques for monitoring the sodium cover gas to determine the total act:ivity of fission product gases have been successful in detecting fuel element failures. However~ these techniques have not proven entirely satisfactory due to their inability to dirferentiate between the decay activity of gaseous fission products released directly from plenum leakers and the gaseous daughter activity of dissolved fission products s~ :
(i.e. iodine and bromine) leached from the nuclear fuel during sodium contact with oxide fuel in the more serious fuel element failures. As a result, such monitoring tech-n:Lques have necessitated reactor shutdowns in the past merely from fisslon gas leaks in the fuel element plenum sections. Such shutdowns due to leakers are unnecessary, costly and result in significant loss of reactor avail-ability.
The halogens iodine and bromine are one class of fission products which are leached readily from oxide fuels by sodium. Normally, iodine and bromine would be gaseous at the temperature of the oxide fuel outer surface. However, in the oxide matrix fission product halogens may not exist in the elemental form because of chemical reactions. Halogens do not normally escape from failed fuel elements which are leaking only fission gases. So monitoring of halogen iso-topes in the sodium coolant would be desirable in order to monitor fuel element failures which are significant in terms of sodium-fuel oxide contact. Unfortunately, direct detection of halogen isotopes in the coolant by gamma ray analysis is impossible because of the presence of short-lived Na(tl/2 = 15 h~. Consequently, a rapid and efficient separation technique is necessary to isolate the radiohalogens for measurement.
SUMMARY OF THE INVENTION
We have discovered a new method for separating halogens from the sodium coolant of a nuclear reactor which is rela-tively simple and inexpensive and by which we are able to S ~ `
near quantitative recovery. Our method consists of passing a quantity of sodium at a temperature above 200C.
into a metal segregation vessel. The vessel and contained r sodium is then cooled to below 120C., w~lereby the halogens present in the sodium adhere to the wall of the segregation vessel. The cooled sodium is then separated from the vessel while the halogens remain on the wall of the vessel.
By recovering the halogens from the wall of the segre-gation vessel and determining their activity, particularly 10 131I, it is possible to determine the absence or presence and possible severity of a fuel element failure within the reactor.
It is therefore one object of the invention to provide an effective and inexpensive method for separating halogens from the coolant of a sodium-cooled nuclear reactor.
It is another object of the invention to provide an effective and inexpensive method for separating iodine and bromine from the coolant of a sodium-cooled nuclear reactor.
Finally, it is the object of the invention to provide 20 an improvement in the method for detecting the presence of a failed fuel element in a sodium-cooled reactor.
DETAILED DESCRIPTION OF THE INVENTION
These and other objects of the invention for the sepa-ration of iodine and bromine from the coo]ant of a sodium-cooled reactor may be met by passing a quantity of liquid sodium coolant at a temperature of above 200 C. into a stainless steel or titanium segregation vessel, cooling the vessel and the coolant to about 100-120 C. 3 whereby ~ 4 --the iodine and bromine in the sodium adhere to the wall of the vessel, and separating the cooled sodium from the vessel whlle the iodine and bromine remain on the wall, thereby separating the iodine and bromine from the coolant.
It is believed that the segregation of halogens will occur in a segregation vessel made of any metal which will withstand the high-temperature sodium environment. However, metals on which segregation of the halogens is known to occur are stainless steel and titanium.
The method of the invention is useful for the quanti- ;
tative recovery of halogens such as iodine and bromine and should be useful for the recovery of chlorine and fluorine. ~ -The process has also been found useful for the complete or partial recovery of other chemical elements which segregate from the coolant (i.e. tritium, antimony, zinc, tantalum and cesium), although the temperatures necessary for their recovery may vary.
The sodium content must be at least 200C. as it is passed into the segregation vessel in order to maintain the halogens and various other chemical elements in solution.
Generally, the temperature of the sodium coolant as it flows through a reactor is at least 350C. or higher. Once the liquid sodium has been passed into the segregation vessel, the vessel and the sodium coolant are cooled to a tempera-ture below 120C. or near the melting point of sodium for the fission products to migrate to and adhere to the sur-face of the segregation vessel. It is preferred that the coolarlt temperature be lowered to between 100-120 C. to 1~7~L4~5 obtain the best results for the recovery of the fission products from the coolant. The sodium may also be allowed to solidify and be removed later by heating to the melting temperature wlthout affecting the results. After the sodium has been cooled to the segregation temperature, it can be removed from the segregation vessel by any con-venient means such as by draining or by forcing out with an inert gas under pressure, while the halogen and other chemical elements will remain on the wall of the vessel.
The volume of liquid-metal-to-surface area of the segregation vessel has not been found to be critical, although it is preferred that the volume-to-surface ratio be as low as possible to provide the most favorable con-ditions for a quantitative recovery of the chemical ele-ments of interest. Volume-to-surface ratios up to about 2 have been shown to provide quantitative halogen recovery.
The halogens are then washed from the wall of the vessel and analyzed by accepted radiochemical methods.
The segregation vessel may be of any convenient size and shape, maintaining a low volume-to-surface area ratio in order to ensure quantitative recovery of halogens from the sodium. For example, the vessel may be a tube, a hollow cylinder or even a pot formed of an appropriate metal.
In the practical use of this invention for separating halogens present in the coolant of a nuclear reactor, a by-pass line containing a removable tube would be con-structed paralleling one of the main sodium-coolant flow 7~5 lines. A portion of the sodium is directed through the by-pass line, preferably in an upward direction to prevent the '~
collection of bubbles in the sodium which may cause a minor reductlon in efficiency on the recovery of the halogens.
When a determination for halogens is desired, the flow through the segregation vessel is stopped by valving off the by-pass line to isolate the segregation vessel. The segregation vessel would then be cooled to 100-120C. so that the halogens in the molten sodium will migrate and adhere to the inner walls of the segregation tube. The cooled sodium would then be forced out of the segregation tube with an inert gas such as argon and the tube removed from the system for analysis of radioactive halogens of interest. From the amount of radioactive iodine present in the tube, the iodine present in the total sodium cooling system can be ascertained.
In an alternative method for determining iodine con-tent, a few volumes of nonradioactive sodium at 100-120C.
could be passed through the segregation vessel to wash away any radioactive sodium-24 adhering to the walls of the segre-gation vessel. The vessel could be left in place and the amount of radioactive iodine present on the inner wall of the vessel could be counted with a lithium drifted germanium detector. This would prevent the necessity for removing the segregation tube from the by-pass line; however, it would be necessary to shield the detector from extraneous radio-activity and from thermal radiation. The activity of the segregated nuclides of interest can be determined by counting . , ~L~7~15 at calibrated geometries. The ~low of the 200C. primar~
coolant can then be directed through the segregation vessel to wash the radioactive iodine and other nuclides from the wall of the vessel and permit a new sample to be started.
,~tlll a further method for completing radioiodine analysis would be to seal the drained vessel in place and allow any short-lived radioiodines to decay to their daughter product xenons, reheat the vessel during a helium purge and concen-trate the evolved xenon daughters on activated charcoal for quantitative gamma-ray analysis of selected xenon isotope,.
The following examples are given as illustrative of the method of the invention and not to be taken as limiting the scope which shall be defined by the appended claims.
EXAMPLE I
A liter of molten sodium at 370C. contained in a ; stainless steel pot having a surface area of 237 square inches with a 13 I concentration of about 2.8 x 105 dis/min/ml was cooled to about 120C. The 131I concentra-tion in the bulk sodium was reduced by about 99% or to 20 about 0.03 x 105 dis/min/ml. In a further experiment using the same stainless steel pot, 200 square inches of york mesh was placed in the sodium which was then heated to 427C. The initial 13lI concentration in the sodium of
2.1 x 105 dis/min/ml was also reduced by 99% or to 0.017 x 105 dis/min/ml when the sodium was cooled to abolJt 120C. The l3lI was found on the vessel wall in the first case and the vessel wall and york mesh in the second case.
The sodium volume-to-surface area ratio for the first and ~7~ L5 second experiments was 1.53 and n . 34 cc/cm , respectivel~.
EXAMPL,E II
A ser:les of experiments were run using EPR-II sod:ium samples which were taken in stainless steel tubes 1/2" in diameter by ]4" in length with an existing sodium sampling system. Each of the frozen sodium samples was trans~erred to an inert gas glove box where the bulk of sodium was melted out of the tubes at about 100-110C. Several radio-nuclides including 3 I segregated and adhered to the wall of the stainless steel tube. The segregated 131I was washed off the wall of the tube and determined by radio-chemical counting techniques. Results of the experiment are shown in the table below.
- ; . ;~
` ` ~ 5 ::
~i I
o ~
~H . ~
~1 OD O~ O~
O
~ U~
a~
~ ~ S Lr~
c~~ l l l "_1 rl ~ E~ o o o C) ~ ~
O-r~ ~ X ~C '.
~~ C~
.~ ~ ~ . . .
,o~~ W ~ L~ ~U
rl~ .:.. `
t~O
,~ ~[ U~
~ ~ . ':.
.
~rl r~ L~
. ~ ~ ~ ~ l l l o .,~ o -- o o o Cl~ ~ c~ rl E~
.. C) ~ ~o H C ~ ~ ~ C
l H ~ td ~ ~ J ~
¢~ ~I Q~ . . .
~ ~ ~ o ~D ~
. ' .~ ~ ~g ~
H
~:}
Q) O~
~d H r~ ~\J N ~1 ~1 ~ ~1 W ~D
~ Z
H
CQ
~7~5 It can be seen from the table that an average of 93.3% of the 31I in the sodium was recovered from the walls of the stainless steel tube.
The preceding examples and discussion o.f the method of this invention for the recovery of halogens ~rom the liquid-sodium coolant of a nuclear reactor is extremely efficient and provides an effective and rapid means for determining the presence of f~iled fuel elements within the reactor.
The sodium volume-to-surface area ratio for the first and ~7~ L5 second experiments was 1.53 and n . 34 cc/cm , respectivel~.
EXAMPL,E II
A ser:les of experiments were run using EPR-II sod:ium samples which were taken in stainless steel tubes 1/2" in diameter by ]4" in length with an existing sodium sampling system. Each of the frozen sodium samples was trans~erred to an inert gas glove box where the bulk of sodium was melted out of the tubes at about 100-110C. Several radio-nuclides including 3 I segregated and adhered to the wall of the stainless steel tube. The segregated 131I was washed off the wall of the tube and determined by radio-chemical counting techniques. Results of the experiment are shown in the table below.
- ; . ;~
` ` ~ 5 ::
~i I
o ~
~H . ~
~1 OD O~ O~
O
~ U~
a~
~ ~ S Lr~
c~~ l l l "_1 rl ~ E~ o o o C) ~ ~
O-r~ ~ X ~C '.
~~ C~
.~ ~ ~ . . .
,o~~ W ~ L~ ~U
rl~ .:.. `
t~O
,~ ~[ U~
~ ~ . ':.
.
~rl r~ L~
. ~ ~ ~ ~ l l l o .,~ o -- o o o Cl~ ~ c~ rl E~
.. C) ~ ~o H C ~ ~ ~ C
l H ~ td ~ ~ J ~
¢~ ~I Q~ . . .
~ ~ ~ o ~D ~
. ' .~ ~ ~g ~
H
~:}
Q) O~
~d H r~ ~\J N ~1 ~1 ~ ~1 W ~D
~ Z
H
CQ
~7~5 It can be seen from the table that an average of 93.3% of the 31I in the sodium was recovered from the walls of the stainless steel tube.
The preceding examples and discussion o.f the method of this invention for the recovery of halogens ~rom the liquid-sodium coolant of a nuclear reactor is extremely efficient and provides an effective and rapid means for determining the presence of f~iled fuel elements within the reactor.
Claims (9)
1. A method for separating halogens from the coolant of a sodium-cooled nuclear reactor comprising:
a. passing a quantity of the molten sodium at a temperature above 200 C, into a metal segregation vessel;
b. cooling the sodium and the vessel to a tem-perature below 120 C. whereby the halogens present in the sodium adhere to the wall of the vessel; and c. separating the cooled sodium from the vessel whereby the halogens remain on the wall of the vessel, thereby separating the halogens from the sodium coolant.
a. passing a quantity of the molten sodium at a temperature above 200 C, into a metal segregation vessel;
b. cooling the sodium and the vessel to a tem-perature below 120 C. whereby the halogens present in the sodium adhere to the wall of the vessel; and c. separating the cooled sodium from the vessel whereby the halogens remain on the wall of the vessel, thereby separating the halogens from the sodium coolant.
2. The method of claim 1 wherein the halogens are selected from the group consisting of iodine and bromine.
3. The method of claim 1 wherein the metal of the segregation vessel is selected from the group consisting of stainless steel and titanium.
4. The method of claim 3 wherein the sodium is cooled to 100 to 120°C.
5. The method of claim 4 wherein the segregation vessel is stainless steel, and the halogen is iodine.
6. The method of claim 4 wherein the segregation vessel is a tube, a small quantity of sodium coolant flows through the tube and the iodine is separated by stopping the flow of sodium through the tube, cooling the tube con-taining the sodium to about 100-120 C., blowing the cooled sodium from the tube with an inert gas and determining the amount of iodine present on the wall of the tube.
7. In the method for detecting a fuel element failure in a liquid-sodium-cooled nuclear reactor wherein the failure causes sodium coolant to contact the fuel material, by detecting the iodine present in the sodium coolant wherein the iodine level indicates the absence or presence and possible severity of such a fuel element failure, the improvement in the method for separating the iodine from the sodium coolant comprising: passing a quantity of sodium coolant at a temperature above 200°C. into a metal segregation vessel; cooling the sodium and the vessel to below 120°C. and above the melting temperature of sodium whereby any iodine present in the sodium will migrate to and adhere to the wall of the segregation vessel; removing the cooled sodium from the vessel whereby the iodine remains on the wall of the vessel; and determining the level of iodine present on the wall of the vessel, the level of iodine indicating the presence and severity or absence of such a fuel element failure.
8. The method of claim 7 wherein the sodium and the segregation vessel are cooled to 100 to 120°C.
9. The method of claim 8 wherein the metal of the segregation vessel is selected from the group consisting of stainless steel and tantalum.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US61445975A | 1975-09-18 | 1975-09-18 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1071415A true CA1071415A (en) | 1980-02-12 |
Family
ID=24461336
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA258,986A Expired CA1071415A (en) | 1975-09-18 | 1976-08-12 | Method for the recovery of halogens from sodium |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS5239513A (en) |
| CA (1) | CA1071415A (en) |
| DE (1) | DE2641998A1 (en) |
| FR (1) | FR2325158A1 (en) |
| GB (1) | GB1543956A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60156986U (en) * | 1984-03-28 | 1985-10-18 | 三機工業株式会社 | Low-temperature and humid fluidized air thawing device with shower |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| UST921014I4 (en) * | 1972-06-09 | 1974-04-16 | Colburn mbthod for removing fission products from a nuclear reactor coolant | |
| UST920001I4 (en) * | 1972-06-15 | 1974-03-05 | Cooper method and apparatus for removing iodine from a nuclear reactor coolant | |
| UST921016I4 (en) * | 1972-09-28 | 1974-04-16 | Removal op radioactive contamination prom a nuclear reactor coolant | |
| US3881989A (en) * | 1973-07-23 | 1975-05-06 | Us Energy | Method of detecting a fuel element failure |
-
1976
- 1976-08-12 CA CA258,986A patent/CA1071415A/en not_active Expired
- 1976-09-06 GB GB36779/76A patent/GB1543956A/en not_active Expired
- 1976-09-16 FR FR7627867A patent/FR2325158A1/en active Pending
- 1976-09-17 DE DE19762641998 patent/DE2641998A1/en active Pending
- 1976-09-17 JP JP51111656A patent/JPS5239513A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| GB1543956A (en) | 1979-04-11 |
| DE2641998A1 (en) | 1977-03-24 |
| JPS5239513A (en) | 1977-03-26 |
| FR2325158A1 (en) | 1977-04-15 |
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