EP2232503B1 - Device for transporting and/or storing radioactive materials and for the controlled release of oxygen in an enclosed housing - Google Patents

Abstract

The invention relates to a device (1) for transporting and/or storing radioactive materials (10), comprising a closed enclosure (8) and a system (12, 16) for securing said closed enclosure, said system comprising catalytic means (12) for recombining hydrogen and oxygen into water, placed in said closed enclosure. According to the invention, the system for securing said closed enclosure further comprises a device (16) for the controlled release of oxygen in said closed enclosure (8).

Description

TECHNICAL AREA

The present invention relates generally to the field of securing a closed enclosure defined in a device for transporting and / or storing radioactive materials.

STATE OF THE PRIOR ART

In such closed enclosures containing radioactive materials, in the presence of water or solid or liquid hydrogen compounds, the radiation emitted by the radioactive materials causes, by radiolysis, a transformation of a part of this water into different gases, including hydrogen and oxygen.

The presence of hydrogen in the enclosure clearly affecting the safety of the entire transport and / or storage device, because of the significant risks of flammability, explosiveness and pressure build-up that it generates, it is therefore usually sought to remove this hydrogen.

For this purpose, the containment enclosures may be equipped with a catalyst for the recombination of oxygen and hydrogen in water (or catalytic hydrogen recombinant), in contact with which hydrogen combines with the oxygen present. inside the enclosure closed to form water according to the catalytic oxidation mechanism of hydrogen.

This principle of catalytic oxidation of hydrogen operates until the oxygen initially contained in the closed chamber is completely consumed. However, from the moment when the oxygen remains too low content within the closed chamber, the aforementioned risks of flammability, explosiveness and rise in pressure, due to the presence too important of hydrogen, reappear.

To overcome the lack of oxygen, one solution is to initially introduce, within the closed enclosure, means for releasing oxygen, constituted for example by a solid source of gaseous oxygen, as is apparent in FIG. particular of the document FR-A-2,874,120 . This solid source takes the form of a peroxide, which, in contact with the water created in the closed chamber, releases gaseous oxygen.

Thus, oxygen is regularly generated within the chamber, but in uncontrollable quantities, which can lead to oxygen deficiency and therefore to an excess of non-recombined hydrogen, with the risks presented above. .

From the prior art, the document is also known EP-A-0 383 153 , describing a device for reducing the internal pressure in a radioactive waste storage device. This device comprises a chamber placed in a lateral body opening or the lid of the waste storage device nuclear. The interior of this chamber receives a catalyst and has an opening in communication with the internal storage space of the storage device, opening in which is placed a sintered metal candle. The catalyst is separated from the outside by a wire cloth, a vapor permeable plate or a sintered metal cover.

The hydrogen that has formed in the storage device passes through the sintered metal candle, then arrives on the catalyst where the hydrogen is oxidized into water by the oxygen in the air. As an indication, the catalyst used comprises a precious metal, for example palladium on an inert support, for example alumina.

In the solution presented by this document, the internal storage space can not be considered as constituting a closed enclosure of a device for transporting and / or storing radioactive materials, since this space can not be closed, sealed and perfectly sealed, because of the need to make it communicate with the ambient air, constituting the external source of oxygen.

STATEMENT OF THE INVENTION

The invention therefore aims to at least partially overcome the disadvantages mentioned above, relating to the achievements of the prior art.

To do this, the invention firstly relates to a device for transporting and / or storing radioactive materials, comprising a closed enclosure and a system for securing said closed enclosure, said system comprising catalytic means for recombining hydrogen and oxygen in water, placed in said closed enclosure. According to the invention, the system for securing said closed enclosure further comprises a device for controlled release of oxygen in said closed enclosure.

With the present invention, the release of oxygen in the closed chamber being now controlled, the risks of insufficiency and / or overflow of oxygen within this chamber are advantageously reduced to nothing, and this during any the duration of storage and / or transport of radioactive material.

It is noted that the controlled release of oxygen into the enclosure can be automated, or not. In the latter case, it may in particular be means allowing an operator to trigger and / or stop itself the supply of oxygen into the chamber, from outside the latter. In addition, if the triggering of the oxygen release, manual or automatic, is preferably performed following the detection of a low oxygen content, it is possible that this triggering is performed differently, for example at several times predetermined, namely at predetermined time intervals, preferably regular. In addition, the invention operates with any type of oxygen release means, allowing a controlled release thereof, these means being placed in or out of the closed chamber. As an indication, it can for example be solid, liquid or gaseous oxygen sources, which, when they are intended to be arranged within the closed chamber, are preferably introduced into it before the closure of the transport and / or storage device, for then stay there permanently.

Thus, the device for the controlled release of oxygen is an integral part of the system for securing the closed enclosure of the device for transporting and / or storing radioactive materials. This system may nevertheless include other active means, without departing from the scope of the invention. For example, the active means may not only comprise a catalyst for recombining oxygen and hydrogen in water, but also a desiccant, for limiting the presence of water inside the enclosure. Indeed, this presence causes significant risks of corrosion, so that it may then be necessary to achieve a cleansing thereof, namely a removal of water with the aid of the desiccant supra. By way of illustrative examples, the recombination catalyst is chosen in particular from platinum or palladium-coated catalysts, and may take the form of palladium deposited on alumina, enabling both catalysis and drying to be carried out together. required.

Naturally, these active means are determined and retained according to the nature of the elements that are sought to be eliminated inside the closed enclosure of the transport device and / or storage, in order to sanitize and / or secure the same enclosure.

• des moyens permettant de renseigner sur la teneur en oxygène au sein de ladite enceinte fermée ;
• des moyens commandables de libération d'oxygène conçus pour libérer de l'oxygène au sein de ladite enceinte fermée ; et
• des moyens de commande desdits moyens de libération d'oxygène.

According to a preferred embodiment, said device for the controlled release of oxygen comprises:

• means for providing information on the oxygen content within said closed chamber;
• controllable oxygen release means adapted to release oxygen within said closed chamber; and
• means for controlling said oxygen release means.

Here, the control of the oxygen release can advantageously result from monitoring information on the oxygen content in the closed chamber, and this that the release of oxygen is done manually or automated. In addition, as will be explained below, the information on the oxygen content may concern the oxygen content itself, or alternatively the content of another gas present in the chamber, correlated with the oxygen content. .

Preferably, said means for informing about the oxygen content are connected to the control means so as to provide a value of the oxygen content within said closed chamber, said control means being designed to order the means of release, an oxygen release, preferably in a predetermined amount, when said value falls below a predetermined threshold of oxygen content.

With this preferred configuration, the control means therefore automatically order the release of oxygen when the content thereof falls below the predetermined threshold, for example set between 2 and 10% of the volume of the closed chamber and even more preferably between 3 and 6% of this volume. By way of indicative example, once the oxygen release ordered, it could be maintained as long as the value of the oxygen content provided by the detection means remains below the aforementioned threshold. In such a case, the release of oxygen is then stopped as soon as the threshold is reached, then a new release of oxygen is ordered only when the detected value goes back below the predetermined threshold.

Alternatively, it can be arranged that, once the oxygen release has been ordered, a determined quantity of oxygen is introduced into the chamber, this determined quantity being fixed, for example, so that, following its release into said closed chamber , the oxygen content is raised to a value between 5 and 60%, and even more preferably between 20 and 30%.

Still preferably, said means for informing about the oxygen content are detection means for detecting the oxygen content in said closed enclosure, preferably of the oxygen sensor type. Nevertheless, solutions alternatives are conceivable, in which the means for informing about the oxygen content are not designed to directly detect the oxygen content, this being in fact obtained indirectly from one or more other values which are correlated to it, such as a value of the content of another gas present in the chamber. Among these gases whose content can be directly detected using appropriate means to provide information on the oxygen content, there are in particular hydrogen and carbon monoxide, or even hydrocarbons, I ₂ , Cl ₂ or CO ₂ . Estimates and / or calculations known to those skilled in the art then make it possible, from one or more of these values of detected contents, to provide information on the oxygen content within said closed enclosure, to then compare it with the predetermined threshold of oxygen content.

Furthermore, in the preferred case of the implementation of detection means for detecting the oxygen content within said closed chamber, these preferably comprise one or more oxygen content sensors disposed within said enclosure closed. In the case of a plurality of sensors, the solution is effective to deduce the average oxygen content in the enclosure, when poor homogeneity remains within it.

Preferably, said oxygen controlled release device is designed to permit multiple time-spaced oxygen releases, with each oxygen release being ordered by said control means when said value falls below said predetermined threshold of oxygen content. The advantage of this type of configuration lies in the fact that it can successively fill the closed chamber with oxygen several times, thus being able to permanently ensure the catalytic recombination of the hydrogen created in the enclosure, without generating an overpressure. of oxygen in the latter. Moreover, this principle can indifferently be realized with a single source of oxygen which can be activated several times successively, for example by opening / closing, or with a plurality of oxygen sources, for example each dedicated to a specific source of oxygen. given release. Other cases are nevertheless possible, such as activating several sources during the same release of oxygen.

In this regard, whatever the technology employed for said oxygen release means, these preferably comprise a plurality of gaseous oxygen sources placed in said closed chamber, said control means comprising a sequencer connected to said sources of oxygen. in order to be able to order their trigger in a sequenced way.

In this hypothesis of successive releases, said control means are preferably designed so as to impose a minimum time interval between two directly consecutive oxygen releases. This makes it possible to avoid causing one or more unwanted oxygen releases, just after a given release. This risk actually exists in the event that the ordered quantity of oxygen is released slowly, and that the oxygen content sensor continues to provide a value below the threshold, in the moments following this release. Another cause may lie in the slow homogenization of the oxygen content in the closed chamber, following an oxygen release.

As an indication, for this purpose, said control means could comprise an activated timer after each release of oxygen, preferably automatically. The timer can apply a delay of several hours, for example 24 hours.

As mentioned above, all of the characteristics that have just been mentioned can be implemented not by following the value of the oxygen content directly detected or indirectly determined, but by following the hydrogen content which informs indirectly on the oxygen content within the closed chamber.

In this respect, it can therefore be provided that said means for informing about the oxygen content are connected to the control means so as to provide a value of the hydrogen content within said closed chamber, said control means being arranged to direct the release means to release oxygen, preferably in a predetermined amount, when said value exceeds a predetermined hydrogen content cap.

With this preferred configuration, the control means therefore automatically order the release of oxygen when the hydrogen content exceeds the predetermined ceiling. By way of indicative example, once the oxygen release ordered, it could be maintained as the value of the hydrogen content provided by the detection means remains above the above ceiling. In such a case, the release of oxygen is then stopped as soon as the ceiling is reached, then a new release of oxygen is ordered only when the detected value goes back above the predetermined ceiling.

Alternatively, it can be arranged that, once the oxygen release has been ordered, a determined quantity of oxygen is introduced into the chamber, this determined quantity being fixed, for example, so that, following its release into said closed chamber , the hydrogen content is reduced to a determined value below the ceiling.

Still preferentially, said means for informing about the oxygen content are detection means for detecting the hydrogen content in said closed chamber, preferably of the hydrogen content sensor type. Nevertheless, alternative solutions are conceivable, in which the means making it possible to provide information on the hydrogen content are not designed to directly detect the hydrogen content, this being in fact obtained indirectly from one or more other values that are correlated to it, such as a value of the content of another gas present in the enclosure. Estimates and / or calculations known to those skilled in the art then make it possible, from one or more of these values of detected contents, to provide information on the hydrogen content within said closed chamber, and then to compare it with the predetermined ceiling of hydrogen content.

Furthermore, in the preferred case of the implementation of detection means for detecting the hydrogen content within said closed enclosure, these preferably comprise one or more hydrogen content sensors disposed within said enclosure closed.

Finally, it is indicated that the means making it possible to provide information on the oxygen content can actually provide a value of the hydrogen content as just described, but alternatively provide a value of the content of one or more of the gases. contained in the chamber, among hydrogen and carbon monoxide, or even hydrocarbons, I ₂ , Cl ₂ or CO ₂ .

Preferably, said control means are arranged outside said closed enclosure, and electrically powered by a power supply also arranged outside said closed enclosure, even if these elements could be placed in the enclosure, without departing from the scope of the invention .

Preferably, said oxygen release means comprise at least one solid source gaseous oxygen placed within said closed chamber, each solid source comprising an oxidizing compound capable of releasing oxygen gas by thermal decomposition. This technical solution, in which the oxidizing compound is preferably chlorate or sodium perchlorate, is perfectly suitable, since it remains compact and thus facilitates the implantation in the enclosure, but also because it allows to know exactly the volume of oxygen gas released for a given solid mass.

As such, each solid source preferably comprises a system for electrically triggering the thermal decomposition of the oxidizing compound, said triggering system being electrically connected to said control means capable of activating it.

• des moyens commandables de libération d'oxygène conçus pour libérer de l'oxygène au sein de ladite enceinte fermée ; et
• des moyens de commande desdits moyens de libération d'oxygène, conçus pour ordonner aux moyens de libération, éventuellement sous condition, plusieurs libérations successives d'oxygène, respectivement à une pluralité d'instants prédéterminés.

According to another preferred embodiment of the present invention, the device for the controlled release of oxygen comprises:

• controllable oxygen release means adapted to release oxygen within said closed chamber; and
• control means for said oxygen release means, adapted to order the release means, possibly under condition, several successive releases of oxygen, respectively at a plurality of predetermined times.

Thus, unlike the previous embodiment, it is based on the principle of successive releases of oxygen at predetermined time intervals, and no longer on the monitoring of the oxygen content within the chamber, even if the oxygen content may be precisely subject to a condition subordinating the release order, as will be described later. Of course, any other conditions deemed useful by those skilled in the art can be retained, without departing from the scope of the invention.

Nevertheless, it can be arranged that the control means of said oxygen releasing means is adapted to direct the releasing means, unconditionally, to release oxygen at each of said plurality of predetermined times.

On the other hand, it can alternatively be made such that said device allowing the controlled release of oxygen furthermore comprises means making it possible to provide information on the oxygen content within said closed enclosure, and that said means making it possible to provide information on the content. in oxygen are connected to the control means so as to provide a value of the oxygen content within said closed chamber, said control means being adapted to order at each of said plurality of predetermined times, the release means, an oxygen release, provided that said supplied value is less than a predetermined value of oxygen content. This ensures that after the release of oxygen, its content in the chamber will remain acceptable. This condition, verified before each release of oxygen, is therefore a safe step to reduce the risks of overoxygenation within the transport device and / or storage.

Preferably, said means for informing about the oxygen content are detection means for detecting the oxygen content within said closed chamber. Nevertheless, the alternatives envisaged for the previous mode are here also applicable. Likewise, the other components of the oxygen controlled release device, described above in connection with the previous mode, are also applicable to this preferred embodiment.

Preferably, each ordered oxygen release results in a release of oxygen in a predetermined amount.

The invention furthermore relates to a method of securing a device for transporting and / or storing radioactive materials, comprising a closed enclosure as well as a system for securing said closed enclosure, said system comprising catalytic recombination means hydrogen and oxygen in water, placed in said closed enclosure. According to the invention, a controlled release of oxygen is achieved in said closed chamber, preferably automated.

Other advantages and features of the invention will become apparent in the detailed non-limiting description below.

BRIEF DESCRIPTION OF THE DRAWINGS

• la figure 1 représente une vue schématique en coupe longitudinale d'un dispositif de transport et/ou de stockage de matières radioactives, selon un mode de réalisation préféré de la présente invention ;
• la figure 2 représente une vue des moyens de libération d'oxygène équipant le dispositif de transport et/ou de stockage montré sur la figure 1 ;
• la figure 3 représente un diagramme illustrant le fonctionnement du dispositif de libération commandée d'oxygène, comportant les moyens de libération d'oxygène montrés sur la figure 2 ;
• la figure 4 représente une vue similaire à celle de la figure 1, avec le dispositif de libération commandée d'oxygène se présentant sous la forme d'un autre mode de réalisation préféré ; et
• la figure 5 représente un diagramme illustrant le fonctionnement du dispositif de libération commandée d'oxygène montré sur la figure 4.

This description will be made with reference to the appended drawings among which;

• the figure 1 is a schematic longitudinal sectional view of a device for transporting and / or storing radioactive materials, according to a preferred embodiment of the present invention;
• the figure 2 represents a view of the oxygen release means equipping the transport and / or storage device shown on the figure 1 ;
• the figure 3 is a diagram illustrating the operation of the controlled oxygen release device, having the oxygen release means shown on the figure 2 ;
• the figure 4 represents a view similar to that of the figure 1 with the oxygen controlled release device in the form of another preferred embodiment; and
• the figure 5 represents a diagram illustrating the operation of the controlled oxygen release device shown in FIG. figure 4 .

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Firstly with reference to the figure 1 , there is shown a device 1 for the transport and / or storage of radioactive material, also called packaging, which is in the form of a preferred embodiment of the present invention.

The device 1 generally comprises a lateral body 2, a bottom 4 possibly made in one piece with the body 2, and a cover 6 fixedly attached thereto. These elements jointly form a closed enclosure 8, in which are housed the radioactive material 10, such as waste cases.

The device 1 comprises a system for securing the closed enclosure 8, this system firstly comprising active means, among which several catalysts 12 for the recombination of oxygen and hydrogen in water, as well as a desiccating agent. (not shown) As has been schematized on the figure 1 the catalysts 12 are preferably distributed in the enclosure 8, in particular to avoid local concentrations of hydrogen.

In addition, the system for securing the closed enclosure comprises a device 16 for the controlled release of oxygen in the chamber 8, the purpose of which is to ensure the catalytic recombination of hydrogen during the entire transport period and / or storage of radioactive material. Consequently, the controlled release of oxygen allowed by the device 16 makes it possible, in particular, to cope with cases in which all of the oxygen initially present in the chamber has been consumed.

The device 16 firstly comprises detection means 20 for detecting the oxygen content in the chamber, these means preferably taking the form of one or more oxygen sensors 20 arranged in the chamber 8 these sensors can take any form known to those skilled in the art.

It also comprises controllable oxygen release means 22, provided to release oxygen within the enclosure 8. In the preferred embodiment described, these means 22 housed in the enclosure comprise a plurality of solid sources 24 of gaseous oxygen, each solid source 24 comprising an oxidizing compound of the chlorate or sodium perchlorate type, capable of releasing gaseous oxygen by thermal decomposition.

Finally, the device 16 comprises control means 26 of the sources 24. These control means, preferably in the form of an electronic control unit, comprise firstly means 28 for acquiring a value of oxygen content continuously supplied by the sensor 20 to which these means 28 are connected. They also make it possible to compare this value with a predetermined threshold of oxygen content in the enclosure, fixed for example between 3 and 6%, and preferably around 5%.

These control means also have means 30 for ordering a release of oxygen contained in the sources 24. The means 30 are therefore capable of generating a signal, for example an electric current, leading to the thermal decomposition of one of the solid sources 24, this signal passing through a sequencer 32 connected to the sources 24 and for conveying this signal from one of these sources not yet consumed. Indeed, the device 16 is designed to allow several time-spaced releases of oxygen, each release of oxygen preferably taking place by activating only one of the sources 24.

In this regard, the control means 26 comprise a timer 34 imposing a minimum time interval between two directly consecutive oxygen releases, and therefore between the actuation of two sources 24, this interval being for example set at about 24 hours.

It is noted that the control means 26 are preferably located outside the enclosure 8, as its power supply 36, which may optionally be integrated.

Therefore, as is schematized on the figure 2 the electrical connections 35 between the sequencer 32 and the solid sources 24 pass tightly through the lateral body 2, such a connection being also provided between the sensor 20 and the means 28 for acquiring and comparing the value of the content of the oxygen.

As mentioned above, each solid source 24 comprises an oxidizing compound 40 capable of releasing oxygen gas by thermal decomposition. Preferably, this oxidizing compound consists of a block of chlorate or sodium perchlorate. To do this, each solid source may consist of an oxygen cartridge / candle having an electrical trigger system for thermal decomposition, this system may for example take the form of an ignition pad 42. The ignition pad 42 receiving the electrical signal from the means 30 and the sequencer 32, via the electrical connection 35 of the wired type connected to this chip, causes a combustion of an electric relay 44 of the candle, which maintains the thermal decomposition of the chlorate block or sodium perchlorate 40, until it is fully consumed. The release of gaseous oxygen which results from this decomposition passes through a filter 46 of the candle, the purpose of which is to trap the harmful species resulting from this decomposition, such as soot, etc.

The mass of the chlorate or sodium perchlorate block 40 makes it possible to accurately determine the quantity of oxygen gas that is released during its thermal decomposition. Thus, it is easily possible to control the quantity of oxygen introduced into the chamber following the order of release of oxygen delivered by the control means 26, this quantity of oxygen being preferably fixed so that following its release into said closed chamber, the oxygen content is raised to a value between 20 and 30%, and preferably of the order of 25%.

The operation of the device 16 will now be described, in particular with reference to the figure 3 .

During the period of storage and / or transport of the radioactive materials in the chamber, the sensor 20 delivers a regular and continuous oxygen content value to the means 28 which compare it to the predetermined threshold. As long as the value is above the threshold, no action is taken. In contrast, if the value falls below the threshold, implying that the remaining amount of oxygen is insufficient to ensure a satisfactory catalytic recombination of the hydrogen in the chamber, an oxygen release order is automatically delivered by the means 30. Through the sequencer 32, this order in the form of an electrical signal is switched to the one of the solid sources 24 which has not yet been consumed, and activates the ignition pad 42 of the same source. Then, oxygen gas is released from this source as discussed above, in an amount which is known, and which can reach several liters. The release can take several minutes or more.

As schematized on the figure 3 , the oxygen release command is immediately followed by a timer applied by timer 34, which prohibits the issuance of a new oxygen release command until a given time interval has elapsed , such as 24 hours. Therefore, during this time interval, even if the value of the oxygen content detected by the sensor 20 is below the threshold, no new source triggering order 24 can be issued.

Once the delay has ended, the value of the oxygen content supplied by the sensor 20 is normally close to the desired ceiling, and therefore much greater than the threshold. The comparison made by the means 28 is then resumed, waiting to detect the new passage of the value below the predetermined threshold, which may occur several days, months or years after the previous one.

Referring now to the figure 4 , there is shown a device 1 for the transport and / or storage of radioactive materials, according to another preferred embodiment of the present invention. Here, only the control means 26 of the device 16 differ from those just presented. In this regard, in the figures, the elements bearing the same reference numerals correspond to identical or similar elements.

The control means 26 of the sources 24 are always in the form of an electronic control unit. They comprise a timer 50 or the like, in which a plurality of predetermined instants T1, T2, .., Tn are programmed, these times being spaced from each other by predetermined, preferably regular, time intervals. As an indicative example, the time interval used is set at several tens of days.

The control means 26 also comprise the means 28 for acquiring an oxygen content value supplied by the sensor 20 to which these means 28 are connected. They also make it possible to compare this value supplied with a predetermined value of oxygen content in the chamber, fixed for example between 30 and 70%, and preferably around 60%.

These control means 26 also have means 30 for ordering an oxygen release contained in the sources 24, as well as the sequencer 32 connected to the sources 24 and making it possible to route the signal from one of these sources not yet consumed. Indeed, the device 16 is designed to allow several time-spaced releases of oxygen, each release of oxygen preferably taking place by activating only one of the sources 24.

The operation of the device 16 will now be described, in particular with reference to the figure 5 .

During the period of storage and / or transport of the radioactive materials in the enclosure, the timer 50 detects the predetermined times T1, T2, .., Tn at which an oxygen release could be ordered. When one of these instants occurs, before performing the release of oxygen, the condition of limited oxygen content is verified by the means 28. In fact, the sensor 20 delivers an oxygen content value to the means 28, which compare it to the predetermined value. In the rarest case where the value supplied is greater than the predetermined value, reflecting a very low unusual consumption of oxygen since the previous release, no action is taken, and no release of oxygen can take place before the next predetermined instant. This case reveals abnormal conditions, an alarm can be triggered when it occurs. On the other hand, if the value supplied is less than the predetermined value, an oxygen release command is automatically delivered by the means 30. When passing through the sequencer 32, this order in the form of an electrical signal is switched to one of the solid sources 24 that has not been consumed, and activates the ignition pad 42 of the same source. Then, oxygen gas is released from this source as discussed above, in an amount which is known, and which can reach several liters. The release can take several minutes or more. Due to the verification of the oxygen limited condition just prior to the release order, there is certainty that the new oxygen content, after the release of a certain amount of oxygen, does not reach a ceiling. criticism synonymous with overoxygenation.

Once the release of oxygen is complete, the means 26 stand by a new predetermined instant T1, T2, .., Tn.

Of course, various modifications may be made by those skilled in the art to the invention which has just been described, solely by way of non-limiting example. In this regard, it is noted that the invention applies not only to waste cases as just presented, but also to any other type of radioactive material.

Claims (14)

1. Device (1) for transporting and/or storing radioactive materials (10), comprising a closed enclosure (8) and a system (12, 16) for securing said closed enclosure, said system comprising catalytic means (12) for recombining hydrogen and oxygen into water, placed in said closed enclosure,
   characterised in that the system for securing said closed enclosure further comprises a device (16) for the controlled release of oxygen in said closed enclosure (8).
2. Device (1) according to claim 1, characterised in that said device (16) for the controlled release of oxygen comprise:

   - means (20) for obtaining data on the oxygen concentration inside said closed enclosure;

   - controllable oxygen release means (22) for releasing oxygen inside said closed enclosure; and

   - means (26) for controlling said oxygen release means.
3. Device (1) according to claim 2, characterised in that said means for obtaining data on the oxygen concentration are connected to the control means (26) so as to supply same with a value of the oxygen concentration inside said closed enclosure, said control means (26) being devised to order the release means (22) to release oxygen, preferably in a predetermined quantity, when said value falls below a predetermined oxygen concentration threshold.
4. Device (1) according to claim 3, characterised in that said means for obtaining data on the oxygen concentration are detection means (20) for detecting the oxygen concentration inside said closed inclosure.
5. Device (1) according to claim 4, characterised in that said detection means (20) comprise one or a plurality of oxygen concentration sensors, arranged inside said closed enclosure.
6. Device (1) according to any of claims 3 to 5, characterised in that said device (16) for the controlled release of oxygen is devised to enable a plurality of oxygen releases spaced over time, each oxygen release being ordered by said control means (26) when said value falls below said predetermined oxygen concentration threshold.
7. Device (1) according to any of claims 2 to 6, characterised in that said control means (26) are devised to set a minimum time interval between two directly consecutive oxygen releases.
8. Device (1) according to claim 7, characterised in that said control means comprise a time delay (34) activated after each oxygen release.
9. Device (1) according to claim 1, characterised in that said device (16) for the controlled release of oxygen comprise:

   - controllable oxygen release means (22) for releasing oxygen inside said closed enclosure; and

   - means (26) for controlling said oxygen release means, for ordering the release means (22), optionally subject to conditions, to perform a plurality of successive oxygen releases, at a plurality of predetermined times (T1, T2,.., Tn), respectively.
10. Device (1) according to claim 9, characterised in that the means (26) for controlling said oxygen release means are devised to order the release means (22), without conditions, to release oxygen at each of said plurality of predetermined times (T1, T2,.., Tn).
11. Device (1) according to claim 9, characterised in that said device (16) for the controlled release of oxygen further comprises means (20) for obtaining data on the oxygen concentration inside said closed enclosure, and in that said means (20) for obtaining data on the oxygen concentration are connected to the control means (26) so as to provide same with a value of the oxygen concentration inside said closed enclosure, said control means (26) being devised to order at each of said plurality of predetermined times (T1, T2,.., Tn) the release means (22) to release oxygen, provided that said value provided is less than the predetermined oxygen concentration value.
12. Device (1) according to claim 11, characterised in that said means for obtaining data on the oxygen concentration are detection means (20) for detecting the oxygen concentration inside said closed enclosure.
13. Device (1) according to any of claims 9 to 12, characterised in that each oxygen release ordered gives rise to release of a predetermined quantity of oxygen.
14. Method for securing a device (1) for transporting and/or storing radioactive materials (10), comprising a closed enclosure (8) and a system (12, 16) for securing said closed enclosure, said system comprising catalytic means for recombining hydrogen and oxygen into water, placed in said closed enclosure (8),
    characterised in that a controlled oxygen release is performed in said closed enclosure (8).

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