CA1107034A - Process for removing tritium from tritium-containing heavy water to recover tritium gas of high purity - Google Patents
Process for removing tritium from tritium-containing heavy water to recover tritium gas of high purityInfo
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- CA1107034A CA1107034A CA299,881A CA299881A CA1107034A CA 1107034 A CA1107034 A CA 1107034A CA 299881 A CA299881 A CA 299881A CA 1107034 A CA1107034 A CA 1107034A
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Abstract
Abstract of the Disclosure:
A process is, herein, disclosed for removing tritium from tritium-containing heavy water to recover tritium gas of high purity characterized by feeding a part of the heavy water containing tritium from a source for supplying the heavy water such as heavy water moderated power reactor to an exchange reaction column wherein the heavy water contacts with deuterium gas countercurrently, extracting heavy water enriched in tritium from the bottom of the exchange reaction column and converting it to vapor of heavy water, passing the vapor of heavy water through at least one packed column of two columns packed with easily oxidizable or reducible metals by steam or hydrogen respectively wherein the metal in the column is oxidized to metal oxide while the vapor of heavy water is reduced to deuterium gas, recycling most of the deuterium gas to the exchange reaction column to effect countercurrent contact between heavy water and deuterium gas, extracting the deuterium gas of reduced tri-tium content from the top of the exchange reaction column, passing said deuterium gas through the other column in which the metal packed has already been oxidized to metal oxide wherein the metal oxide is reduced to metal while the deuterium gas is oxidized to heavy water and recycling a part of the heavy water of reduced tritium content to the heavy water supplying source while recycling the residual heavy water to the top of the exchange reaction column, introducing a part of the gas obtained after passing the vapor of heavy water through the heated metal layer to the thermal diffusion column cascade and concentrating the tritium to recover the tritium as tritium gas of high purity.
A process is, herein, disclosed for removing tritium from tritium-containing heavy water to recover tritium gas of high purity characterized by feeding a part of the heavy water containing tritium from a source for supplying the heavy water such as heavy water moderated power reactor to an exchange reaction column wherein the heavy water contacts with deuterium gas countercurrently, extracting heavy water enriched in tritium from the bottom of the exchange reaction column and converting it to vapor of heavy water, passing the vapor of heavy water through at least one packed column of two columns packed with easily oxidizable or reducible metals by steam or hydrogen respectively wherein the metal in the column is oxidized to metal oxide while the vapor of heavy water is reduced to deuterium gas, recycling most of the deuterium gas to the exchange reaction column to effect countercurrent contact between heavy water and deuterium gas, extracting the deuterium gas of reduced tri-tium content from the top of the exchange reaction column, passing said deuterium gas through the other column in which the metal packed has already been oxidized to metal oxide wherein the metal oxide is reduced to metal while the deuterium gas is oxidized to heavy water and recycling a part of the heavy water of reduced tritium content to the heavy water supplying source while recycling the residual heavy water to the top of the exchange reaction column, introducing a part of the gas obtained after passing the vapor of heavy water through the heated metal layer to the thermal diffusion column cascade and concentrating the tritium to recover the tritium as tritium gas of high purity.
Description
~7ll;~
.
Back~round of the Invention:
(1) ~ield of the Invention:
~ his invention relates to a process for removing tritium from tritium-containing heavy water.
.
Back~round of the Invention:
(1) ~ield of the Invention:
~ his invention relates to a process for removing tritium from tritium-containing heavy water.
(2) Description o~ the prior art:
~ he ~aue-Langevin Ins-titute process developed in France is publicly known as one typical process for remov-ing tritium senerated in the heavy wa-ter used in the heavy water moderated-power reactor to rec~over tritium of high purity. ~his ~aue-~angevin Institute process is characterized by using a combination of an excha~e reac tion column for effecting an exchange reaction between the vapor of heavy water and deuterium gas in parallel flow at 200C with a cryogenic liauified hydrogen disti]lation column for effect-ing the concentration of the trltium in the deuterium gas~
However, since the Laue-Langevin process uses a column wherein vapor of heavy water has to absolutely con-tact with deuterium gas in parallel flow at 200G, several exchange-reaction columns are required, because the apparatus used to carry out the Laue-Langevin Institute proces~s should be constructed countercurrently as a whole. In addition to that, since tritium is concentrated and separated by virtue of cryogenic liouified hydrogen distillation after moving tritium into deuterium gas in the ~a~e-~angevin Institute process, the Laue-Langevin Institute process requires a helium cycle for generating cryogenic temperatures.
As stated above, the Laue-Langevin Institute process has several defects in that the apparatus used to carry out the process and the operation of the appara~us are very - 2 - ~
~ 3 ~
complicated and, also 9 high level techniques are require'd to carry out the process.
In order to eliminate the defects of the ~aue-~angevin Institute process as stated above, the inventors of this invention studied and found the novel process of this invention.
Summary of the Invention:
It is, therefore, an object of this invention to provide a novel process for removing and recovering tritium which eliminates the defects of the conventional art and simplifies the apparatus used as a whole and which can be easily controlled from the standpoint o~ radiation-pxotection.
_ief Description of Drawin~:
Fig. 1 is a schematic process flow diagram ~or practicing the process of this invention.
Detailed Descri~tion o~ the Invention:
This invention relates to a process for removing tritium from tritium-containing heavy water to recover tritium gas of high purity.
~his invention is characterized b~ feeding a part of the heav~ water containin~ tritium from a source ~or supplying the heavy water such as heavy water moderated-power reactor (hereinunder referred as "heavy water supply-ing source") to an exchange reaction column wherein the heavy water contacts with deuterium gas countercurrently, extracting heavy water enriched in tritium ~rom ~he bottom of the exchange reaction column and converting it to vapor of hea~y water, passing the vapor of heavy water through at least one packed column of two columns packed with ~0 easily oxidizable or reducible metals by steam or hydrogen .~
~ he ~aue-Langevin Ins-titute process developed in France is publicly known as one typical process for remov-ing tritium senerated in the heavy wa-ter used in the heavy water moderated-power reactor to rec~over tritium of high purity. ~his ~aue-~angevin Institute process is characterized by using a combination of an excha~e reac tion column for effecting an exchange reaction between the vapor of heavy water and deuterium gas in parallel flow at 200C with a cryogenic liauified hydrogen disti]lation column for effect-ing the concentration of the trltium in the deuterium gas~
However, since the Laue-Langevin process uses a column wherein vapor of heavy water has to absolutely con-tact with deuterium gas in parallel flow at 200G, several exchange-reaction columns are required, because the apparatus used to carry out the Laue-Langevin Institute proces~s should be constructed countercurrently as a whole. In addition to that, since tritium is concentrated and separated by virtue of cryogenic liouified hydrogen distillation after moving tritium into deuterium gas in the ~a~e-~angevin Institute process, the Laue-Langevin Institute process requires a helium cycle for generating cryogenic temperatures.
As stated above, the Laue-Langevin Institute process has several defects in that the apparatus used to carry out the process and the operation of the appara~us are very - 2 - ~
~ 3 ~
complicated and, also 9 high level techniques are require'd to carry out the process.
In order to eliminate the defects of the ~aue-~angevin Institute process as stated above, the inventors of this invention studied and found the novel process of this invention.
Summary of the Invention:
It is, therefore, an object of this invention to provide a novel process for removing and recovering tritium which eliminates the defects of the conventional art and simplifies the apparatus used as a whole and which can be easily controlled from the standpoint o~ radiation-pxotection.
_ief Description of Drawin~:
Fig. 1 is a schematic process flow diagram ~or practicing the process of this invention.
Detailed Descri~tion o~ the Invention:
This invention relates to a process for removing tritium from tritium-containing heavy water to recover tritium gas of high purity.
~his invention is characterized b~ feeding a part of the heav~ water containin~ tritium from a source ~or supplying the heavy water such as heavy water moderated-power reactor (hereinunder referred as "heavy water supply-ing source") to an exchange reaction column wherein the heavy water contacts with deuterium gas countercurrently, extracting heavy water enriched in tritium ~rom ~he bottom of the exchange reaction column and converting it to vapor of hea~y water, passing the vapor of heavy water through at least one packed column of two columns packed with ~0 easily oxidizable or reducible metals by steam or hydrogen .~
3~a respectively wherein the metal in the column is oxidized to metal oxide while the vapor of heavy water is reduced to deuterium gas, recycling most of the deuterium gas to the exchange reaction colu~n to effect the countercurrent contact between heavy water and deuterium gas~ extracting the deuterium gas of reduced tritium content from the top of the exchange reaction column, passing said deuterium ~as throu~h the other column in which the metal packed has already been oxidized to metal oxide wherein the metal oxide is reduced to metal while the deuterium gas is oxidized to heavy wa-ter and rec~cling a part of the heav~ water of reduced tritium content to the heav~ water supplying source while recycling the resldual heavy water to the top of the exchange reaction column. And this invention is ~urther characterized by introducing a part of the gas obtained after passing the vapor of heavy water through the metal-packed column to the thermal diffusion column cascade and concentrating the tritium to recover the tritium as tritium gas of high purity.
Description of a Preferred Embodimen-t:
One mode contemplated for practici~g this invention will be described in detail below in connection with the accompanying drawing.
As can be seen from ~igo 17 one embodim~nt of the apparatus to carr~ out this invention comprises a heavy water moderated power reactor 1~ an exchange reaction column 2 packed with hydrophobic platinum catal~st, a ; packed column ~, that is an oxidation-reduction column packed with easily oxidizable or reducible metals and hot-wire type thermal diffusion column cascade 4. ~he packed .
`` ~L~ 7 ~ ~ ~
column 3 comprises column A and column B and is provided with two valves 5 and 6 which can be mutually switched over so that one of the metals charged can be reduced to be regenerated while the other metals are being oxidized.
System components are connected with each other b~ piping.
In Fig. 1~ continuous lines represent flow of li~uid and broken lines represent flow of gas.
Tritium is produced in heavy water used in heavy water moderated-power reactor ~ and exists generally in the form of D~0. A part of the heavy water containing tritium extracted from heavy water moderated-power reactor 1 is introduced through the piping 7 into the fixed poin-t of the exchange reaction column 2 while heavy water of reduced tritium content is introduced into the top of the exchange reaction column 2 through the piping 8. In the exchange reaction column 2, the heavy waters introduced through the piping 7 and 8 are mlxed together and subjected to the following exchange reaction with deuterium containing tritium coming up from the bottom of the column 2 by virtue o~ the h~drophobic platinum catalyst packed in the column;
DT ~ D20 ~__~ D2 ~ DT0 ..~.. (1) The exchange reaction (1) is shifted to right at low tem-peratures and to left at high temperatures and the separation ~actor of the reaction at 20C is expressed by;
[DT0] / ~D20]
[ D-T~ - = 1.61 ... ~. (2) [DT] / ~D2 ]
:
7~
~heref~re, the tritium-containing heavy water supplied in the exchange reaction column 2 extracts tritium from the deuterium as ~ ~roceeds up the column 2, and at the same time the tritium-containing heavy water flows donw the column 2 at room temperature and reaches the bottom of the column 2 and then is extracted outside the column 2 thx~gh piping 9 to be introduced through the change-over valve 6 and piping 10 into the column B of the oxidation-reduction column where in accordance with the following equations (3) and (4) the heavy water vapor containing tritium is converted to deuterium gas containing tritium by virtue of easily oxidazable-reducible heated metal packed thereln, for example particles of ~ i alloy or powder of Ni - ~i alloy supported on a carrier.
D20 + M 3 D2 ~ M0 ............ (3) D~0 ~ M ~ DT + M0 ~OO~ (4) M : Ni - Ti alloy M0 : oxides of ~ i alloy from column B of the oxidation reduction apparatus 3 the deuterium gas passes through piplng 11, change-over valve 5 and piping 12. Most of the deuterium gas passed throùgh piping 12 is recycled to the bottom of exchange-reaction column 2 through piping 13 and 14 while the remainder is introduced through piping 15 to the gas receiving section 4a of the hot-wire type thermal diffusion column cascade 4 In Fig. 1, 4b represents the txitium enriching section and 4c represents the tritium stripping section. In the hot-wire type thermal diffusion colum~ cascade 4, the following .
.
~ `:
7~
xchange reacbion (5) is continuously taking place by virtue of the catalysis of red-hot wire of, for example, nickel, chromium alloy, tungsten, platinum and so forth and tr.~ium gas is concentrated at the bo~om o~ ~he hot-wire type thermal diffusion column cascade 4 to be recoveredas tritium gas of higher purity than 9~/c through piping 16 2D~ D2 + ~2 (5) On the other hand, in tritium stripping section 4c of the hot-wire type thermal diffusion column cascade 4, deuterium gas having lo~er tritium content than that in the deuterium gas introduced to said ca~cade 4 through piping 15 is recovered and extracted from the top of the cascade
Description of a Preferred Embodimen-t:
One mode contemplated for practici~g this invention will be described in detail below in connection with the accompanying drawing.
As can be seen from ~igo 17 one embodim~nt of the apparatus to carr~ out this invention comprises a heavy water moderated power reactor 1~ an exchange reaction column 2 packed with hydrophobic platinum catal~st, a ; packed column ~, that is an oxidation-reduction column packed with easily oxidizable or reducible metals and hot-wire type thermal diffusion column cascade 4. ~he packed .
`` ~L~ 7 ~ ~ ~
column 3 comprises column A and column B and is provided with two valves 5 and 6 which can be mutually switched over so that one of the metals charged can be reduced to be regenerated while the other metals are being oxidized.
System components are connected with each other b~ piping.
In Fig. 1~ continuous lines represent flow of li~uid and broken lines represent flow of gas.
Tritium is produced in heavy water used in heavy water moderated-power reactor ~ and exists generally in the form of D~0. A part of the heavy water containing tritium extracted from heavy water moderated-power reactor 1 is introduced through the piping 7 into the fixed poin-t of the exchange reaction column 2 while heavy water of reduced tritium content is introduced into the top of the exchange reaction column 2 through the piping 8. In the exchange reaction column 2, the heavy waters introduced through the piping 7 and 8 are mlxed together and subjected to the following exchange reaction with deuterium containing tritium coming up from the bottom of the column 2 by virtue o~ the h~drophobic platinum catalyst packed in the column;
DT ~ D20 ~__~ D2 ~ DT0 ..~.. (1) The exchange reaction (1) is shifted to right at low tem-peratures and to left at high temperatures and the separation ~actor of the reaction at 20C is expressed by;
[DT0] / ~D20]
[ D-T~ - = 1.61 ... ~. (2) [DT] / ~D2 ]
:
7~
~heref~re, the tritium-containing heavy water supplied in the exchange reaction column 2 extracts tritium from the deuterium as ~ ~roceeds up the column 2, and at the same time the tritium-containing heavy water flows donw the column 2 at room temperature and reaches the bottom of the column 2 and then is extracted outside the column 2 thx~gh piping 9 to be introduced through the change-over valve 6 and piping 10 into the column B of the oxidation-reduction column where in accordance with the following equations (3) and (4) the heavy water vapor containing tritium is converted to deuterium gas containing tritium by virtue of easily oxidazable-reducible heated metal packed thereln, for example particles of ~ i alloy or powder of Ni - ~i alloy supported on a carrier.
D20 + M 3 D2 ~ M0 ............ (3) D~0 ~ M ~ DT + M0 ~OO~ (4) M : Ni - Ti alloy M0 : oxides of ~ i alloy from column B of the oxidation reduction apparatus 3 the deuterium gas passes through piplng 11, change-over valve 5 and piping 12. Most of the deuterium gas passed throùgh piping 12 is recycled to the bottom of exchange-reaction column 2 through piping 13 and 14 while the remainder is introduced through piping 15 to the gas receiving section 4a of the hot-wire type thermal diffusion column cascade 4 In Fig. 1, 4b represents the txitium enriching section and 4c represents the tritium stripping section. In the hot-wire type thermal diffusion colum~ cascade 4, the following .
.
~ `:
7~
xchange reacbion (5) is continuously taking place by virtue of the catalysis of red-hot wire of, for example, nickel, chromium alloy, tungsten, platinum and so forth and tr.~ium gas is concentrated at the bo~om o~ ~he hot-wire type thermal diffusion column cascade 4 to be recoveredas tritium gas of higher purity than 9~/c through piping 16 2D~ D2 + ~2 (5) On the other hand, in tritium stripping section 4c of the hot-wire type thermal diffusion column cascade 4, deuterium gas having lo~er tritium content than that in the deuterium gas introduced to said ca~cade 4 through piping 15 is recovered and extracted from the top of the cascade
4 and then is recycled to the bottom of the exchange reac-tion column 2 through pipings 17 and 14. ~ritium-containing _.
deuterium gas introduced into the bottom of the exchange-reaction column 2 from the top of the packed column 3,~that is, the oxidation-reduction column, and from the top of -the hot-wire type thermal diffusion column cascade 4 contacts the heavy water coming down from the top of the column 2 countercurrently through the h~drophobic platinum catalyst bed and consequentl~ tritium contained in deuterium gas is mov~d to the heavy water side. Therefore, when the tritium~
containing deuterium gas introduced into the column 2 reaches . the top of the column 2, the tritium content o~ the deuterium gas is lowe~ ~nd the gas is extracted from the top of -the column 2 through piping 18 to be introduced into column A
of oxidation-reduction column 3 through change-over valve
deuterium gas introduced into the bottom of the exchange-reaction column 2 from the top of the packed column 3,~that is, the oxidation-reduction column, and from the top of -the hot-wire type thermal diffusion column cascade 4 contacts the heavy water coming down from the top of the column 2 countercurrently through the h~drophobic platinum catalyst bed and consequentl~ tritium contained in deuterium gas is mov~d to the heavy water side. Therefore, when the tritium~
containing deuterium gas introduced into the column 2 reaches . the top of the column 2, the tritium content o~ the deuterium gas is lowe~ ~nd the gas is extracted from the top of -the column 2 through piping 18 to be introduced into column A
of oxidation-reduction column 3 through change-over valve
5 and piping 19~ In the column A, the metal oxide is reduced 7~3~
to metal, there~y preparing for the next cycle for reduction of vapor of heavy water to deuterium; on the other hand~
deuterium is oxidized to heavy water as shown by the following equations (6) and ~7);
D2 ~ D20 ~ M 0.O.O ~6) DT 1- MO -~ DTO ~ M ......... (7) ~M : Ni - ~i alloy ~MO : oxide o~ i alioyJ
The heavy water produced in the column A as stated above passes through piping 20, change-over valve 6 and piping 21 and ~hen a part of the heavy water passed through piping 21 is recycled to the heavy water moderated-power reactor 1 while the remainder is recycled to the top o~ the exchange reaction column 2 through piping 23 and 8. Oxidation-reduction appara-tus 3 comprises two columns A and B and is provided with two valves 5 and 6 which can be mutually switched over so that an oxidation reaction is carried out in column A while a reduction regeneration reaction is carried out in column B7 and ~ reduction regeneration reaction is carried out in column A while an oxidation reaction is carried out in column B.
It is, therefore, possible to remove tritium ~rom tritium-; containing heavy water to recover tritium gas of high purity.
This m vention is further illustrated by the follow-ing Example. However, this invention should not be limited by the ~xample, and changes and modi~ications within the - spirit and scope of the claim can be effected.
~- ~xample A 25 x 104 K~ie hea~y water moderated power reactor :
1 was employed as heavy water supplying source.
About 100 tons of heavy water are used in 25 x 104 KWe heavy water moderated power reactor as moderator and ~ri-tium is generated in the heavy water. If the tritium is not removed, a steady state of the tritium concentration is about 50 Ci/l of heavy water. Therefore, this Example is carried out in case of recovery of tritium gas 9g~ or higher purity while maintaining the tritium concentration in heavy water at 0.5 Ci/l.
Heavy water containing tritium is extracted at the rate of 70Q/hour from the heavy water of 100 tons charged in th~ 25 x 104 KWe heav~ water moderated-power reactor 1 and supplied into exchange-reaction column 2. The exchange-reaction column 2 comprises 20 theoretical plates -that is, 15 theo-retical plates in the tritium enriching section and 5 theoreti-cal plates in the tritium stripping section, and is packed with hydrophobic pla~inum particle catalyst and operated at 20Co The tritium-containing heavy water introduced into the exchange-reaction column 2 extracts tritium from deuterium gas which flows up the column 2, as the tritium-containing heavy water flows down the column 2 and reachesthe bottom of the column 2 and then is intxoduced into the packed column 3, that is the oxidation-reduction column.
The packed column 3 comprises two columns A and B and is ;!` operated at temperatures of 400C - 800C and the deuterium gas produced in the step of oxidation of metal packed in the column 3 is fed into hot-wire type thermal diffusion cascade 4 after removing as much as possible of the vapour of heavy water contained in the deuterium gas. The cascade 4 comprises 5 stages of hot-wire type thermal diffusion ~;
7~
.
column having hot-wire of iron ~1~5 mm (~) x 2000 mm) heated at temperatures of 700C to 800C and its outer wall is cooled by water. ~he cascade 4 as a whole, is operated at temperatures of 40a to 50C under atmospheric pressure~ ~he separation factor in the tritlum enriching section 4b of the cascade 4 is 104 and in the tritium stripping section 4c of the cascade 4 it is 10. About 25g (about 250,000 Ci) of tritium gas of 99.5% in purity are removed and recovered per year. On the other hand, the deuterium gas leaving from the top o~ the exchange-reaction column 2 is introduced into the packed column ~ and is converted to heavy water and its tritium concentration is 0.05 Ci/l. And then, a part of the heavy water is recycled to heavy water moderated power reactor 1 and the remainder is recycled to exchange reaction column 2. q`he amount o~
heavy water supplied through piping 24 to the top of the exchange-reaction column 2 as replenishment is less than about 100g per year.
The ~xample above illustrated is relating to the removal and recovery of tritium in heav~ water charged in a heavy water moderated power reactor;- however, this invention is not limited thereto but is also applicable to the removal of tritium from tritium-containing light water produced in reprocessing of nuclear ~uel.
~he process of this invention can be operated at atmospheric pressure and requires no rotating machine except for means for cycling heavy water and deuterium gas. And since a conversion of heavy water to deuterium and a con-version of deuterium -to heavy water are carried out in -turn in a single apparatus and the metals packed in the apparatus _ 10 -~7~3~
can be regenerated simultaneously in the apparatus, the facilities to carry out this invention are very much simplified as a whole. And further, with this invention it is particularly easy to maintain radiation protection control, and if a heavy water moderated power reactor is employed as the heavy water supplying source to carry out this invention, it is very advantageous for safety control of power reactor. And if the process of this invention is applied to nuclear fuel reprocessing plant, tritium can be completely removed from tritium-containing waste water with-out contamination of environment.
to metal, there~y preparing for the next cycle for reduction of vapor of heavy water to deuterium; on the other hand~
deuterium is oxidized to heavy water as shown by the following equations (6) and ~7);
D2 ~ D20 ~ M 0.O.O ~6) DT 1- MO -~ DTO ~ M ......... (7) ~M : Ni - ~i alloy ~MO : oxide o~ i alioyJ
The heavy water produced in the column A as stated above passes through piping 20, change-over valve 6 and piping 21 and ~hen a part of the heavy water passed through piping 21 is recycled to the heavy water moderated-power reactor 1 while the remainder is recycled to the top o~ the exchange reaction column 2 through piping 23 and 8. Oxidation-reduction appara-tus 3 comprises two columns A and B and is provided with two valves 5 and 6 which can be mutually switched over so that an oxidation reaction is carried out in column A while a reduction regeneration reaction is carried out in column B7 and ~ reduction regeneration reaction is carried out in column A while an oxidation reaction is carried out in column B.
It is, therefore, possible to remove tritium ~rom tritium-; containing heavy water to recover tritium gas of high purity.
This m vention is further illustrated by the follow-ing Example. However, this invention should not be limited by the ~xample, and changes and modi~ications within the - spirit and scope of the claim can be effected.
~- ~xample A 25 x 104 K~ie hea~y water moderated power reactor :
1 was employed as heavy water supplying source.
About 100 tons of heavy water are used in 25 x 104 KWe heavy water moderated power reactor as moderator and ~ri-tium is generated in the heavy water. If the tritium is not removed, a steady state of the tritium concentration is about 50 Ci/l of heavy water. Therefore, this Example is carried out in case of recovery of tritium gas 9g~ or higher purity while maintaining the tritium concentration in heavy water at 0.5 Ci/l.
Heavy water containing tritium is extracted at the rate of 70Q/hour from the heavy water of 100 tons charged in th~ 25 x 104 KWe heav~ water moderated-power reactor 1 and supplied into exchange-reaction column 2. The exchange-reaction column 2 comprises 20 theoretical plates -that is, 15 theo-retical plates in the tritium enriching section and 5 theoreti-cal plates in the tritium stripping section, and is packed with hydrophobic pla~inum particle catalyst and operated at 20Co The tritium-containing heavy water introduced into the exchange-reaction column 2 extracts tritium from deuterium gas which flows up the column 2, as the tritium-containing heavy water flows down the column 2 and reachesthe bottom of the column 2 and then is intxoduced into the packed column 3, that is the oxidation-reduction column.
The packed column 3 comprises two columns A and B and is ;!` operated at temperatures of 400C - 800C and the deuterium gas produced in the step of oxidation of metal packed in the column 3 is fed into hot-wire type thermal diffusion cascade 4 after removing as much as possible of the vapour of heavy water contained in the deuterium gas. The cascade 4 comprises 5 stages of hot-wire type thermal diffusion ~;
7~
.
column having hot-wire of iron ~1~5 mm (~) x 2000 mm) heated at temperatures of 700C to 800C and its outer wall is cooled by water. ~he cascade 4 as a whole, is operated at temperatures of 40a to 50C under atmospheric pressure~ ~he separation factor in the tritlum enriching section 4b of the cascade 4 is 104 and in the tritium stripping section 4c of the cascade 4 it is 10. About 25g (about 250,000 Ci) of tritium gas of 99.5% in purity are removed and recovered per year. On the other hand, the deuterium gas leaving from the top o~ the exchange-reaction column 2 is introduced into the packed column ~ and is converted to heavy water and its tritium concentration is 0.05 Ci/l. And then, a part of the heavy water is recycled to heavy water moderated power reactor 1 and the remainder is recycled to exchange reaction column 2. q`he amount o~
heavy water supplied through piping 24 to the top of the exchange-reaction column 2 as replenishment is less than about 100g per year.
The ~xample above illustrated is relating to the removal and recovery of tritium in heav~ water charged in a heavy water moderated power reactor;- however, this invention is not limited thereto but is also applicable to the removal of tritium from tritium-containing light water produced in reprocessing of nuclear ~uel.
~he process of this invention can be operated at atmospheric pressure and requires no rotating machine except for means for cycling heavy water and deuterium gas. And since a conversion of heavy water to deuterium and a con-version of deuterium -to heavy water are carried out in -turn in a single apparatus and the metals packed in the apparatus _ 10 -~7~3~
can be regenerated simultaneously in the apparatus, the facilities to carry out this invention are very much simplified as a whole. And further, with this invention it is particularly easy to maintain radiation protection control, and if a heavy water moderated power reactor is employed as the heavy water supplying source to carry out this invention, it is very advantageous for safety control of power reactor. And if the process of this invention is applied to nuclear fuel reprocessing plant, tritium can be completely removed from tritium-containing waste water with-out contamination of environment.
Claims (5)
- Claim 1 continued diffusion column cascade and concentrating the tritium to recover tritium gas of high purity; provided that the metals packed in the packed column are oxidized and reduced in turn while the process is carried out.
- 2. The process of Claim 1, in which the source for sup-plying the heavy water is a heavy water-moderated power reactor.
- 3. The process of Claim 1, in which the exchange reaction column is packed with a hydrophobic platinum catalyst.
- 4. The process of Claim 1, in which the packed column is provided with two valves which can be mutually switched over.
- 5. The process of Claim 1, in which the thermal diffusion column cascade includes a gas receiving section, a tritium enriching section and a tritium stripping section.
1. A process for removing and recovering tritium from heavy water containing tritium which comprises;
feeding a part of the heavy water containing tritium from a source for supplying the heavy water to an exchange reaction column wherein the heavy water contacts with deuterium containing tritium countercurrently;
extracting heavy water enriched in tritium from the bottom of the exchange reaction column and converting it to vapor of heavy water;
passing the vapor of heavy water through at least one packed column of two columns packed with easily oxidizable and reducible metals to reduce the vapor of heavy water to deuterium gas;
recycling most of the deuterium gas to the exchange reaction column to effect countercurrent contact between the heavy water and deuterium gas;
extracting the deuterium gas of reduced tritium content from the top of the exchange reaction column;
passing said deuterium gas through the other column of two columns in which the metal packed has already been oxi-dized to metal oxide wherein the metal oxide is reduced to metal for regeneration while the deuterium gas is oxidized to heavy water;
recycling a part of the heavy water obtained to the heavy water supplying source while recycling the residual heavy water to the exchange reaction column;
introducing a part of the gas obtained after passing the vapor of heavy water through the packed column to a thermal
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3492377A JPS53120097A (en) | 1977-03-29 | 1977-03-29 | Removing method of tritium |
| JP34923/1977 | 1977-03-29 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1107034A true CA1107034A (en) | 1981-08-18 |
Family
ID=12427723
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA299,881A Expired CA1107034A (en) | 1977-03-29 | 1978-03-29 | Process for removing tritium from tritium-containing heavy water to recover tritium gas of high purity |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS53120097A (en) |
| CA (1) | CA1107034A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111921345A (en) * | 2020-08-18 | 2020-11-13 | 深圳市瑞麟科技有限公司 | Deuterium gas generator heavy water recovery device |
-
1977
- 1977-03-29 JP JP3492377A patent/JPS53120097A/en active Granted
-
1978
- 1978-03-29 CA CA299,881A patent/CA1107034A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111921345A (en) * | 2020-08-18 | 2020-11-13 | 深圳市瑞麟科技有限公司 | Deuterium gas generator heavy water recovery device |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS53120097A (en) | 1978-10-20 |
| JPS5523659B2 (en) | 1980-06-24 |
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