JP7018445B2 - Packaging for transport and / or storage of radioactive material with an improved fluid communication system inside and outside the containment vessel - Google Patents

Description

The present invention relates to packaging for transporting and / or storing radioactive material. More specifically, the present invention relates to a system for fluid communication inside and outside the containment vessel, and more particularly to a system for fluid communication when these systems are not sealed.

Packaging for transporting and / or storing radioactive material has the main function of isolating the contents from the external environment. To do this, the packaging has a containment vessel containing radioactive material. This sealed containment is carried out with several packaging elements, typically sides, and a cover and bottom.

Conventionally, these packaging elements are provided with a system for fluid communication between the inside and outside of the containment vessel. This can be, for example, a ventilation system that allows ventilation to the containment vessel. It could also be a drainage system that allows residual water to be extracted from the containment when the packaging is loaded underwater. Finally, it could also be a system for sampling the gas in the containment vessel.

The outer ends of these systems, also known as "outer fluid outlet zones," are usually connected to shielded tools for drainage or ventilation, which shielded tools during drainage, ventilation or gas sampling operations. It is equipped with a sealing system that ensures that the containment vessel for radioactive materials remains in a guaranteed condition.

In transport and / or containment configurations, these outer ends are sealed with one or several plugs in which the sealing system is located, which are involved in the containment demarcation. The plugs also form a radiation shield to limit the radiation leaks associated with these systems and generally have the form of a straight path through the packaging elements described above. In this regard, each fluid communication system can be interlocked with two plugs, each with at least one seal in such a manner as to form a double sealing barrier if required for the containment vessel. Note that it is arranged.

In particular during operations with packaging, such as conventional or accidental draining operations that require the plug seal to be changed and therefore the plug must be removed while the containment contains radioactive material. In addition, the level of radiation protection on the fluid communication system can be inadequate. The level of dose equivalent rate can then be higher than the standard required for the operation.

Accordingly, the present invention has an object of at least partially overcoming the above problems relating to embodiments of the prior art.

To do this, the present invention has the purpose of packaging for transporting and / or storing radioactive material, and comprises several packaging elements that concatenate and internally separate the storage containers for radioactive material. At least one of the packaging elements is passed by at least one fluid communication system, and the at least one fluid communication system has at least one fluid inlet opening on the inner surface of the containment vessel and is associated with the packaging element. With a sealing plug covering the fluid outlet zone in a manner such that the fluid outlet zone on the outer surface of the fluid outlet zone has at least one fluid outlet opening and the fluid communication system seals the at least one fluid outlet opening. It is associated.

According to the present invention, the fluid communication system defines at least two separate fluid circulation paths between the at least one fluid inlet opening and the at least one fluid outlet opening.

Accordingly, the present invention provides, in a unique manner, replication of the circulatory pathway, which provides a satisfactory compromise between the simplicity of the shape of the associated pathway and the radiation protection involved in the case of plug removal. Enables. Providing several paths with smaller cross sections, no longer a single path, enables the ability of packaging elements placed within the fluid communication system to absorb gamma radiation occurring in all directions. Allows to increase. However, it should be noted that the various circulation pathways can share a common zone without departing from the framework of the present invention.

Further, the present invention makes it possible to limit the dose rate when the plug is placed.

The invention preferably has at least one of the following optional features individually or in combination.

The fluid communication system comprises N1 or more fluid inlet openings and N2 or more fluid outlet openings, where number N1 is greater than, equal to, or less than N2.

The sealing plug is at least partially housed within a housing disposed on the associated packaging element, the housing being defined by the fluid outlet zone on the outer surface of the same packaging element. Alternatively, no specific housing is provided for the plug, in which case the plug is placed fully projecting on this outer surface of the packaging element. In this regard, in the assembled position, the plug either covers each fluid outlet opening or penetrates at least one of the fluid outlet openings.

Separate fluid circulation paths are performed using several basic passages that have a larger cross section and communicate with at least one main passage that is provided in fewer than the number of the basic passages, and each main passage is a fluid circulation path. Some parts of it are defined. Further, each main passage opens to the fluid outlet zone and the basic passage opens to the containment vessel, or each main passage opens to the containment vessel and the basic passage opens to the fluid outlet zone. In this configuration, the packaging preferably comprises two basic passages opening into the containment vessel and a single main passage opening into the fluid outlet zone.

Alternatively, separate fluid circulation paths are performed with several basic passages, each opening to the containment vessel on the one hand and opening to the fluid outlet zone on the other, with each basic passage being one of the fluid circulation paths described above. Is defined.

Yet another possibility is to arrange, for example, a network of secondary passages connecting the two main passages with a single main entrance passage opening to the containment vessel and a main exit passage opening to the fluid outlet zone. It is in the fact.

The basic passage and / or the main passage (s) are straight or not perfectly straight by having at least one bend and / or one chicane.

The basic passages and / or main passages (s) of the same fluid communication system are part of the same virtual surface.

All or part of the separate fluid circulation path is performed within the insert attached to the packaging element involved. The use of inserts provides larger equipment for performing the path and allows consideration of a wider variety of shapes such as bends or equivalents.

The fluid communication system more preferably forms a drainage system, aeration system or gas sampling system.

Finally, a tungsten plate may be added to the packaging element near the fluid communication system to strengthen the shield against gamma radiation. Any other high density material may also be considered to form this additional barrier to gamma radiation.

Other advantages and features of the invention will be revealed from the following detailed, non-limiting description.

This description is described with respect to the accompanying drawings below.
FIG. 6 is a longitudinal sectional view of a packaging for storing and / or transporting radioactive material according to the present invention. FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1 showing a fluid communication system disposed in one of the packaging elements shown in FIG. FIG. 2 is a diagram similar to FIG. 2 in which a plug is arranged in a fluid communication system. It is a cross-sectional view along the line III-III of FIG. It is a cross-sectional view along the line IV-IV of FIG. It is the same figure as FIG. 2 by another embodiment. It is the same figure as FIG. 5 which shows another preferable embodiment again. It is the same figure as FIG. 5 which shows another preferable embodiment again. It is the same figure as FIG. 5 which shows another preferable embodiment again. It is the same figure as FIG. 5 which shows another preferable embodiment again.

First, with reference to FIG. 1, a diagram is shown as a longitudinal cross-sectional view of the packaging for transport and / or storage of radioactive material such as an irradiated fuel assembly or radioactive waste 3. The packaging 1 is shown in the vertical storage position, in which case its major axis 2 is vertically oriented.

The packaging 1 comprises a containment vessel 4 internally separated by a plurality of packaging elements, the packaging element comprising a bottom 6, a side body 8 and an occlusion system with one or several covers 10. There is. In the following description, for the sake of brevity, it is assumed that this system includes a single cover 10. However, when several covers overlap, the invention is more specifically implemented on the innermost cover, which provides direct access to containment 4.

The bottom 6 and the cover 10 are separated from each other according to the long axis 2, and the side body 8 having a circular cross section or a polygonal shape is centered on the long axis 2.

The packaging 1 further comprises a top shock absorbing hood 12 as well as a bottom shock absorbing hood (not shown). The top shock absorbing hood 12 is provided with a hollow zone 16 centered on the shaft 2, which accommodates at least one portion of the cover 10 as well as the top end 8a of the side body 8.

The cover 10 is removably clamped onto the side body 8, more preferably using screws 22, one of which is illustrated by its axis.

In the embodiments described and shown, the side body 8 has a fluid communication system 30 specific to the present invention at its apex 8a, which will be described below with reference to FIGS. 2-4.

First, it is noted that the system 30 may form an exhaust system, a ventilation system, or a gas sampling system. The system 30 is associated with a sealing plug 32 that is involved in defining the containment vessel 4 when sealing the system 30. The plug also forms a radiation shield to limit radiation leakage in cooperation with the system 30.

When the plug 32 is removed, the system 30 is a shielded tool for drainage or ventilation with a sealing system that ensures that the containment of radioactive material remains guaranteed while the operation is being performed. Provided to work together.

The communication system 30 now passes through the end of the top 8a of the side body 8 entirely formed by the metal ferrule 34 radially covered with the nuclear protective layer 36. The system 30, which has the outline of a network of passages, has two fluid inlet openings 38a, 38b on the inner surface 40 of the containment vessel 4. Further, the system 30 includes a single fluid outlet opening 39 on the fluid outlet zone 42 of the outer surface 44 of the side body. Once attached, the plug 32 associated with the system 30 covers the fluid outlet zone 42, as can be seen in FIG. 2a. It is also a portion of the outer surface 44 covered by the plug 32 that separates the fluid outlet zone 42 according to the present invention. In this attached position, the plug 32 seals the fluid outlet opening 39 by covering the fluid outlet opening 39 or by penetrating into the fluid outlet opening 39.

In this preferred embodiment, the fluid outlet zone 42 defines a housing 48 disposed to accommodate at least one portion of the sealing plug 32 when the sealing plug 32 occupies its mounting position. Therefore, in this embodiment, the plug 32 is at least partially integrated with the side body 8 as seen in FIG. 2a.

One of the peculiarities of this packaging is the fact that the fluid communication system 30 defines two separate fluid circulation paths 46a, 46b between the inside and outside of the containment vessel 4. More specifically, the first path 46a begins at the first fluid inlet opening 38a, from which the first basic passage 48a with, for example, a 90 ° bend 50 extends. Similarly, the second path 46b begins at the second fluid inlet opening 38b, from which a second basic passage 48b, also with a bend 50 at about 90 °, extends, for example. The two basic passages 48a and 48b each have an upstream portion and a downstream portion separated by a bent portion 50. The two upstream parts are substantially parallel, while the two downstream parts are confounding axes, merging at the confluence with the main passage 52, which comprises the two fluid circulation paths 46a, 46b. Define a common downstream part.

The main passage 52 is preferably linear and has an axis parallel to the two axes of the upstream portion of the two basic passages 48a, 48b. Preferably the axis of the main passage 52 is located between the two above axes dispersed symmetrically with respect to this axis of the main passage. Further, the passages 48a, 48b, 52 are preferably part of the same surface 54 illustrated in FIG. 4, corresponding to the cross section of the packaging, i.e. orthogonal to its axis 2. It is noted that when the system 30 is installed on a cover, the virtual plane into which the passage is integrated is preferably the longitudinal plane of the packaging through its axis 2.

In this embodiment, the single main passage 52 terminates at a fluid outlet opening 39 that opens into the housing 48 defined by the fluid outlet zone 42. Therefore, the two paths 46a and 46b open into the housing 48 after merging in the main passage 52.

In order to better control the flow between the inlet openings 38a and 38b and the outlet openings 39, the basic passages 48a and 48b each have a smaller cross section than the main passage 52. Preferably, the sum of the cross sections of the two basic passages 48a, 48b is the same as or similar to the higher cross section of the main passage 52.

The passages 48a, 48b, 52 are formed directly in the ferrule 34 on the inner surface 40 of the containment vessel, or in the insert 60 added in the housing 62 formed in the ferrule. This latter solution, shown in the figure, makes it possible to facilitate passage execution, especially if the passage contains a 90 ° bend.

FIG. 5 shows another embodiment in which the plug 32 is no longer located in the housing and projects entirely over the outer surface 44 of the side body. In this case, the plug 32 covers the fluid outlet zone 42 on the surface 44 and covers the outlet opening 39.

6a-6d show other embodiments that may be considered, all sharing the same inventive concept aimed at providing several fluid circulation pathways associated with the same sealing plug 32.

In FIG. 6a, the two basic passages 48a and 48b are separated from each other, defining two independent fluid circulation paths 46a and 46b, respectively. The passages are straight and sloping with respect to each other in a V-shaped manner. The basic passages 48a, 48b therefore extend between the inlet openings 38a, 38b and the fluid outlet openings 39a, 39b.

In FIG. 6b, the embodiment differs from the previous embodiment in that the basic passages 38a and 38b further integrate one chicane 64.

In the embodiment of FIG. 6c, the design is different from the design of FIG. 5 due to the simple fact that the upstream portions of the basic passages 48a, 48b are no longer parallel and are inclined with respect to each other to form a V-shape. It's different.

Finally, in the embodiment of FIG. 6d, the design is by disposing a main passage 52 extending from the inlet opening 38 and two basic passages 48a, 48b terminating at the two exit openings 39a, 39b, respectively. This is the reverse of the design shown in FIG. In this embodiment, the two separate passages 46a, 46b are entangled upstream in the main passage 52 before being separated by passing through the two basic passages 48a, 48b, respectively.

Of course, various modifications can be made by those skilled in the art to the present invention described solely as a non-limiting example. In particular, the various embodiments detailed above can be combined with each other. Further, the fluid communication system peculiar to the present invention can be mounted not only on the side body 8 as described above, but also through the bottom 6 and then through the cover 10. Further, the number N1 of the fluid inlet openings and the number N2 of the fluid outlet openings may be a number exceeding 2 without departing from the framework of the present invention.

1 Packaging 3 Radioactive material 4 Containment vessel 6,8,10 Packaging element 30 Fluid communication system 32 Plug 38 Ferrule 38a, 38b Inlet opening 39a, 39b Fluid outlet opening 39 Outlet opening 40 Inner surface 42 Fluid outlet zone 44 Outer surface 46a, 46b Route 48 Housing 48a, 48b Basic passage 52 Main passage 60 Insert 62 Housing 64 Chicane

Claims (10)

Packaging (1) for transport and / or storage of radioactive material, several packaging elements (6,8,10) that internally separate the storage container (4) of the radioactive material (3) together. At least one of the packaging elements is passed by at least one fluid communication system (30), and the at least one fluid communication system (30) is at least on the inner surface (40) of the storage container. At least one fluid outlet opening (39, 39a, 39b) having one fluid inlet opening (38, 38a, 38b) and in the fluid outlet zone (42) on the outer surface (44) of the associated packaging element. The fluid communication system cooperates with a sealing plug (32) covering the fluid outlet zone (42) in such a manner as to seal the at least one fluid outlet opening.
The fluid communication system (30) has the at least one fluid inlet opening (38, 38a, 38b) opened in the inner surface (40) of the containment vessel (4) and the at least one fluid outlet opening (38, 38a, 38b). Packaging (1) that defines at least two separate fluid circulation paths (46a, 46b) between 39,39a, 39b). The fluid communication system comprises N1 or more fluid inlet openings (38, 38a, 38b) and N2 or more fluid outlet openings (39, 39a, 39b), wherein the number N1 is greater than the number N2. The packaging according to claim 1, which is equal or less. The sealing plug (32) is at least partially housed in a housing (48) disposed on the associated packaging element and the fluid outlet zone on the outer surface (44) of the same packaging element. The packaging according to claim 1 or 2, as defined by (42). A separate fluid circulation path (48a, 48b) with a larger cross section and several basic passages (48a, 48b) communicating with at least one main passage (52) provided less than the number of basic passages (48a, 48b). 46a, 46b) are executed, and each main passage (52) defines some parts of the fluid circulation path (46a, 46b).
Further, each main passage (52) opens into the fluid outlet zone (42), the basic passage opens into the containment vessel (4), or each main passage (52) opens into the containment vessel (4). The packaging according to any one of claims 1 to 3, wherein the basic passages (48a, 48b) open into the fluid outlet zone (42). 4. The packaging comprises two basic passages (48a, 48b) opening into the containment vessel (4) and a single main passage (52) opening into the fluid outlet zone (42). The described packaging. Separate fluid circulation paths (46a, 46b) are performed using several basic passages (48a, 48b), one opening to the containment vessel (4) and the other opening to the fluid outlet zone (42). Being done
The packaging according to any one of claims 1 to 3, wherein each basic passage (48a, 48b) defines one of the fluid circulation paths (46a, 46b). The basic passages (48a, 48b) and / or the main passages (s) are linear or completely by having at least one bend (50) and / or one chicane (64). The packaging according to any one of claims 4 to 6, which is not linear. The packaging according to any one of claims 4 to 7, wherein the basic passage and / or the main passage (s) are part of the same virtual surface (54). 13. Packaging. The packaging according to any one of claims 1 to 9, wherein the fluid communication system (30) forms a drainage system, a ventilation system or a gas sampling system.

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