Process and apparatus for treating activated and / or contaminated components from nuclear plants

Abstract

The present invention relates to an apparatus (100) and a process for treating activated and / or contaminated components (90). In particular, the apparatus (100) comprises a container (10) comprising an internal volume (V). The container (10) is provided with a closure element (20) which is movable between an operating opening configuration of the container (10) and an operating closing configuration thereof. The apparatus (100) further comprises an inflatable joint (50), configured to operate in association with said closure element (20) so as to achieve a watertight sealing of the container (10) when said container is in the operating closing configuration. The apparatus (100) further comprises a cutting device (40) arranged inside the internal volume (V) of said container (10), at least one effluent treatment device (60) and at least one fluid suction device (70) communicating with the internal volume (V) of said container (10) and with said treatment device (60) of an effluent.

Description

[0001] PROCESS AND APPARATUS FOR TREATING ACTIVATED AND / OR CONTAMINATED COMPONENTS FROM NUCLEAR PLANTS

[0002] DESCRIPTION

[0003] Technical area

[0004] The present invention relates to the field of the treatment and disposal (decommissioning) of components from nuclear plants.

[0005] Specifically, the invention relates to an apparatus and process for the treatment of activated and / or contaminated components, in particular configured into elements of complex geometry, in particular elongated, such as the control rods of a nuclear plant.

[0006] Technological background

[0007] The decommissioning of nuclear plants consists of the recovery and treatment of the activated and / or contaminated components, as well as the insertion of the waste materials in special packaging containers and the transport thereof to temporary or permanent storage.

[0008] In particular, some activated and / or contaminated elements having a complex geometry, in particular having an elongated shape, must be segmented in advance to reduce their size and facilitate their handling and storage.

[0009] Conventional cutting methods, such as mechanical cutting or thermal cutting, are ineffective in the nuclear field due to the large amount of dust produced by cutting. Depending on whether the operations are carried out wet or dry, these dusts contaminate the water or air surrounding the cutting area.

[0010] In the specific case of dry cutting, the environment must be kept under constant vacuum by continuous ventilation and all radioactive particles must be captured by a filtering system. If, on the other hand, cutting is carried out under water, decontamination of the water by recirculation, mechanical filtration followed by chemical filtration, e.g. using ion exchange resins, is required.

[0011] According to the latter type of cutting, decommissioning personnel normally stand on the edge or above a water basin (tank or pool) in order to be able to visually execute and control the material treatment process as well as the intake, and transfer of activated and / or contaminated components, or others that are related to the process itself.

[0012] At present, the dispersion of radioactive material in a segmentation pool of the aforesaid components results, as mentioned, in extensive water contamination as well as the need to recover the dispersed material. The operation is definitely complex and can involve the operating personnel being significantly exposed to ionising radiations, as well as a dilation of the overall cutting times and connected costs.

[0013] According to one type of known cutting systems, the segmentation of components is carried out by mechanical cutting in a pool under remote conditions; this mode leads to an undesirable dispersion of swarf and cutting residues as well as necessitating frequent cutting tool changes.

[0014] A further type of cutting system used under water is the so-called AWJC (acronym for Abrasive Water Jet Cutter) which, despite the greater efficiency of the segmentation process, leads to the presence of extensive contamination of the processing pool due to radioactive iron dust mixed with the abrasive in the form of sludge emitted during the process itself.

[0015] In both modes of segmentation, wet or dry, the removal of dispersed dust is time-consuming, as well as costly and produces a significant volume of nuclear waste to be disposed of (e.g. filters and ion exchange resins). The invention proposes to provide an apparatus and process for treating radioactive material - i.e. activated and / or contaminated components - from decommissioning of nuclear facilities, in particular configured in elements of complex geometry, or having an elongated shape, which allows one or more of the above-mentioned limits to be overcome with reference to the prior art mentioned above.

[0016] Description of the invention

[0017] In particular, it is the object of the present invention to present an apparatus for treating activated and / or contaminated components of complex geometry, in particular having an elongated conformation, which allows said components to be efficiently segmented, while avoiding the dispersion of contaminating and / or contaminated material into the surrounding environment.

[0018] A further object of the present invention is to present an apparatus for the treatment of activated and / or contaminated components that can be easily configured and sized according to the size of the elements to be treated, and that entails lower disposal costs than apparatuses of the prior art.

[0019] Another object of the present invention is to present a process for treating activated and / or contaminated components that has a lower environmental impact than processes of the prior art.

[0020] Furthermore, the object of the present invention is to present an apparatus and process for the treatment of activated and / or contaminated components that ensures optimal protection of the personnel involved in the treatment process.

[0021] Finally, the object of the present invention is to present an apparatus and process for the treatment of activated and / or contaminated components, which allows for the appropriate and concentrated storage of processing residues.

[0022] These and other objects of the present invention are achieved by an apparatus and process incorporating the features of the accompanying claims, which form an integral part of the present description.

[0023] According to a first aspect, the present invention relates to an apparatus for treating activated and / or contaminated components comprising a container, which comprises an internal volume, and is provided with a closure element, which is movable between an operating opening configuration of the container and an operating closing configuration thereof.

[0024] Preferably the apparatus comprises an inflatable joint, configured to operate in association with said closure element so as to achieve a watertight sealing of the container when said container is in the operating closing configuration. Preferably, the apparatus comprises a cutting device, arranged inside the internal volume of said container.

[0025] Preferably, the apparatus comprises at least one effluent treatment device.

[0026] Preferably the apparatus comprises at least one fluid suction device communicating with the internal volume of said container and with said effluent treatment device.

[0027] According to this solution, an apparatus for the treatment of activated and / or contaminated components is provided, which allows said components to be treated efficiently, in particular by segmenting them, advantageously avoiding the dispersion of contaminating and / or contaminated material into the surrounding environment

[0028] This also ensures optimal protection of the personnel involved in the treatment process. The present invention, in the aforesaid aspect, may have at least one of the following preferred features, taken individually or in combination with any other one of the preferred characteristics described.

[0029] Preferably, the cutting device is configured to operate by an abrasive water jet.

[0030] Preferably, the cutting device is moved, according to a predefined path, in translation along the axes of a Cartesian tern as well as in rotation about an axis substantially perpendicular to a bottom wall of said container.

[0031] Preferably, said activated and / or contaminated components consist of elements having a complex geometry.

[0032] Preferably, said activated and / or contaminated components consist of elements with an elongated shape.

[0033] Preferably, the apparatus comprises at least one support configured to receive and support at least one elongate-shaped element arranged so that a main direction of said elongate-shaped element is arranged substantially parallel to the bottom wall of said container.

[0034] Preferably, said container is arranged on the bottom of a water basin.

[0035] In a second aspect, the present invention relates to a process for treating activated and / or contaminated components comprising arranging at least one activated and / or contaminated component in a horizontal position on a bottom wall of a container comprising an internal volume, said container being provided with a closure element which is movable between an operating opening configuration of the container and an operating closing configuration thereof.

[0036] Preferably, the process comprises moving the closure element so as to obtain said operating closing configuration of the container. Preferably, the process comprises activating an inflatable joint, configured to operate in association with said closure element so as to achieve a watertight sealing of the container.

[0037] Preferably, the process comprises providing and activating a cutter arranged inside the internal volume of said container so as to operate a segmentation action of said activated and / or contaminated components.

[0038] Preferably, the process comprises providing and activating an effluent treatment device.

[0039] Preferably, the process comprises providing and activating a fluid suction device communicating with the internal volume of said container and with said effluent treatment device.

[0040] In this way, a process is carried out for the treatment of activated and / or contaminated components that entails lower disposal costs compared to processes of the prior art and at the same time has a lower environmental impact.

[0041] According to a preferred form, the process involves, following said segmentation action, deactivating said inflatable joint and subsequently moving the closure element so as to achieve the operating opening configuration of the container.

[0042] Preferably, in the treatment process, the cutting device is configured to operate by an abrasive water jet.

[0043] Preferably, an amount of water equal to 115 I and an amount of corundum equal to 16 kg are used to carry out said segmentation action of each activated and / or contaminated component.

[0044] Brief description of the drawings

[0045] The invention is described hereinbelow with reference to certain examples provided by way of non-limiting example and illustrated in the accompanying drawings. These drawings illustrate different aspects and embodiments of the present invention and reference numerals illustrating structures, components, materials and / or similar elements in different drawings are indicated by similar reference numerals, where appropriate.

[0046] Figure 1 illustrates a schematic drawing of an apparatus for treating activated and / or contaminated components, according to an embodiment of the present invention; and

[0047] Figure 2 shows a schematic plan view of a detail of the apparatus in Figure 1.

[0048] Preferred embodiment of the invention

[0049] While the invention is susceptible to various modifications and alternative constructions, certain preferred embodiments are shown in the drawings and are described hereinbelow in detail. It must in any case be understood that there is no intention to limit the invention to the specific embodiment illustrated, but, on the contrary, the invention intends covering all the modifications, alternative and equivalent constructions that fall within the scope of the invention as defined in the claims.

[0050] The use of "for example", "etc.", "or" indicates non-exclusive alternatives without limitation unless otherwise indicated. The use of "includes" means "includes, but not limited to" unless otherwise indicated.

[0051] With initial reference to Figure 1, 100 denotes an apparatus for treating activated and / or contaminated components, in particular with an elongated shape, in accordance with a first embodiment of the present invention.

[0052] In particular, the apparatus 100 comprises a container 10 which comprises an internal volume V, and is provided with a closure element 20 movable between an operating opening configuration of the container 10 and an operating closing configuration thereof.

[0053] According to a preferred embodiment, the closure element 20 is moved by movement means (not shown in the figures), preferably consisting of hydraulic pistons.

[0054] The apparatus 100 also comprises a cutting device 40, which is arranged inside the internal volume V of the container 10.

[0055] In a preferred embodiment, said cutting device 40 uses a 60 kW abrasive water jet technology, AWJC (acronym for Abrasive Water Jet Cutter). Preferably, the abrasive used by the cutting device 40 comprises corundum, advantageously also allowing efficient cutting of metallic elements, such as when cutting control rods from nuclear plants. Preferably, the cutting device 40 uses a high-pressure flow of water and abrasive, i.e. having a value comprised between about 4000 and about 6000 bar.

[0056] The apparatus 100 further comprises an inflatable joint 50, configured to operate in association with the closure element 20 so as to achieve a watertight sealing of the container 10 when said container is in the operating closing configuration.

[0057] Furthermore, the apparatus 100 comprises a treatment device 60 for treating the effluent resulting from the material segmentation process, in particular, said treatment device 60 is arranged externally to the container 10 and is fed by means of a fluid suction device 70, which is placed in communication with the internal volume V of the container 10.

[0058] According to a preferred embodiment of the invention, the treatment device 60 is configured to operate a separation of the fluid from the waterjet cutting and transfer of the suspension (which in the described embodiment comprises corundum powder and metal powder from the water jet cutting) into drums, preferably having a volume of about 440 I and suitable for conditioning in cement mortar for final storage.

[0059] Preferably, the cutting device 40 is moved according to a predefined path, in translation along the axes of a Cartesian tern (not shown in the figures) wherein the x-axis lies in the plane parallel to a bottom wall 11 of the container 10; the apparatus is also configured in such a way that the cutting device 40 can be placed in rotation about the x-axis of said Cartesian tern.

[0060] In an alternative embodiment, the cutting device 40 can be moved on five axes, three in translation and two in rotation.

[0061] The apparatus 100 further comprises at least one support 80 configured to receive and support the activated and / or contaminated components to be treated, preferably comprising elongate-shaped elements 90. Said support is configured and arranged inside the internal volume V of the container 10 so that a main direction of each elongate-shaped element 90 is arranged substantially parallel to the bottom wall 11 of said container 10.

[0062] Preferably, said supports 80 are made of high-strength steel.

[0063] In a preferred embodiment, the bottom wall 11 of the container 10 is associated with a drainage support 12 and the container 10 further comprises a process fluid outflow channel 13, as shown in Figure 1.

[0064] Preferably, the outflow channel 13 is inclined with respect to the horizontal direction as well as to the bottom wall 11 of the container 10, so that the fluid resulting from the treatment process, permeating through the drainage supportl2, is facilitated in flowing towards the suction device 70, which will be advantageously positioned near a lower portion of said outflow channel 13.

[0065] Preferably, the container 10 further comprises a compartment 14 arranged below the bottom wall 11 of the container 10, preferably below the outflow channel 13, which is configured to accommodate ballast elements 15.

[0066] According to the described embodiment, the container 10 is arranged on the bottom 16 of a water basin so that the bottom wall 11 of the container 10 is substantially parallel to the bottom 16 of said water basin. Thanks to the presence of the ballast elements 15, the stability of the positioning of the container 10 on the bottom 11 of the water basin during the treatment process is advantageously guaranteed.

[0067] According to a preferred embodiment, the water basin has a depth comprised between about 4 and about 6 m.

[0068] In the process of treating the activated and / or contaminated components, one or more elongate-shaped elements 90 are initially arranged - for example by means of a transfer rod provided with a gripper for gripping said elements - in a substantially horizontal position (parallel to the bottom wall 11 of the container 11 on supports 80 arranged on the bottom wall 11 of the container 10 and configured to receive and support at least one elongate-shaped element 90.

[0069] Preferably, the container 10 is configured to receive two elongate-shaped elements 90 arranged parallel to each other, each on respective supports 80 so as to provide the treatment process according to the invention.

[0070] According to a preferred form, each elongate-shaped 90 element consists of four blades, preferably having a width of about 200 mm, a thickness of about 5.5 mm and an overall length of about 3,000 mm.

[0071] Once the elongate-shaped elements 90 have been arranged on their respective supports 80, the container 10 is brought into the closing configuration by affixing the closure element 20, and the inflatable joint 50 is then activated, by injecting air or fluid into it, so that it expands and creates a watertight seal of the container 10 with which it is associated.

[0072] Following this operation, the suction device 70 is then actuated so as to remove the fluid contained in the container 10 and subsequently, when substantially all residual fluid has been removed from the container 10, the cutting process of the elongate-shaped elements 90 can be activated.

[0073] According to an example, the cutting process may involve the following operations in sequence:

[0074] - three longitudinal cuts of the "wings" are made along the axis of the elongate-shaped elements 90, each 2.75 m in length for a total of 8.25 m; the wings remain in place because they are held by the head and foot of the elongate-shaped element 90 itself;

[0075] - 2 transverse cuts are made at the head and foot of the elongateshaped element equal to 0.217 m x 2, for a total of 0.43 m;

[0076] - a transverse cut is made at the centreline of the elongate-shaped element equal to 0.217 m, for a total of approximately 9 m.

[0077] Once the cutting of the elongate-shaped elements 90 is complete, a flow of washing water is introduced into the container 10, preferably at high pressure, in order to remove any solid pollutant particles (e.g. boron carbide, but possibly consisting of other elements) that may have released from the elongate-shaped element 90, as well as any dust resulting from the cutting process, such as steel and corundum.

[0078] Preferably, the cutting water and any washing water are removed by the suction device 70 and sent to the treatment device 60. In a preferred embodiment, the removal of cutting water and / or washing water occurs continuously during the treatment process.

[0079] The separated solid particles - consisting of activated and non-activated solid material in addition to pulverised corundum and silicon carbide powder - are then re-suspended and transferred to a cement mortar conditioning unit (not shown in the figures), where they are stored in standard 440 I stainless steel containers - with a disposable impeller - qualified for delivery to a special depot.

[0080] Preferably, the container 10 is connected to a general ventilation system (not shown in the figures), both during the cutting process and during the decontamination and container 10 emptying step.

[0081] At the end of the cutting operations and the removal of the fluids from the internal volume of the container 10, the inflatable joint 50 is deactivated, i.e. the air in it is blown out of it so that the volume of this joint 50 returns to its initial dimensions and the airtightness of the container is removed.

[0082] Following this, the closure element 20 is moved so as to provide the operating opening configuration of the container 10 and the segmented elements are preferably grasped by means of a service rod equipped with a suitable gripper (not shown in the figures) and transferred to a special storage box 95, located at the apparatus 100.

[0083] According to the invention, the cutting itself takes place "dry" (in air) inside the container 10 which is hermetically sealed during the cutting process itself, thanks to the action of the inflatable joint 50.

[0084] In the preferred embodiment described with reference to Figure 1, the container is placed inside a pool of water to limit the radiation of the personnel supervising the process as much as possible, as the water depth provides excellent radiation shielding.

[0085] This solution is preferable especially when the elements to be treated are activated elements.

[0086] In the case of treatment of contaminated elements, the same segmentation process can be conducted, operating the treatment apparatus according to the invention but avoiding placing the container 10 under water.

[0087] This possibility derives from having an apparatus that in itself guarantees the absence of contamination in the air or on the surfaces surrounding it. Thus, since the contaminated elements have a significantly lower dose of radioactive elements than those in active elements, the additional shielding resulting from the water depth may not be necessary, and an apparatus whose construction and utilisation costs are further reduced can be provided. The invention thus conceived is susceptible to several modifications and variations, all falling within the scope of the inventive concept.

[0088] For example, all the equipment in the treatment apparatus 100 is powered at 24 V and the apparatus 100 has batteries, preferably lithium batteries, to enable it to be secured in the event of a power failure.

[0089] Approximately 115 I of water and 16 kg of corundum are preferably used for each cut element. The washing water of the apparatus 100 is estimated to be about 10 times the internal volume of the container 10.

[0090] According to alternative embodiments, to further limit contamination problems - however unlikely - the external walls of the container 10 can advantageously be covered with a removable film.

[0091] In practice, the materials used, as well as the contingent shapes and sizes, can be whatever according to the requirements without for this reason departing from the scope of protection of the following claims.

Claims

CLAIMS1. Apparatus (100) for treating activated and / or contaminated components (90) comprising:- a container (10) comprising an internal volume (V), said container (10) being provided with a closure element (20) which is movable between an operating opening configuration of the container (10) and an operating closing configuration thereof;- an inflatable joint (50), configured to operate in association with said closure element (20) so as to achieve a watertight sealing of the container (10) when said container is in the operating closing configuration;- a cutting device (40) arranged inside the internal volume (V) of said container (10);- at least one effluent treatment device (60);- at least one fluid suction device (70) communicating with the internal volume (V) of said container (10) and with said effluent treatment device (60).

2. Apparatus (100) according to claim 1, wherein said cutting device (40) is configured to operate by an abrasive water jet.

3. Apparatus (100) according to claim 1 or 2, wherein said cutting device (40) is moved, according to a predefined path, in translation along the axes of a Cartesian tern as well in rotation about an axis substantially perpendicular to a bottom wall (11) of said container (10).

4. Apparatus (100) according to any one of the preceding claims, whereinsaid activated and / or contaminated components consist of elements having a complex geometry, preferably with an elongated shape (90).

5. Apparatus (100) according to claim 4, comprising at least one support (80) configured to receive and support at least one elongate-shaped element (90) arranged so that a main direction of said elongate-shaped element (90) is arranged substantially parallel to the bottom wall (11) of said container (10).

6. Apparatus (100) according to any one of the preceding claims, wherein the container (10) is arranged on the bottom (16) of a water basin.

7. Process for treating activated and / or contaminated components (90) comprising:- arranging at least one activated and / or contaminated component in a horizontal position on a bottom wall (11) of a container (10) comprising an internal volume (V), said container (10) being provided with a closure element (20) which is movable between an operating opening configuration of the container (10) and an operating closing configuration thereof;- moving the closure element (20) so as to obtain said operating closing configuration of the container (10);- activating an inflatable joint (50), configured to operate in association with said closure element (20) so as to achieve a watertight sealing of the container (10);- providing and activating a cutting device (40) arranged inside the internal volume (V) of said container (10) so as to operate a segmentation action of said activated and / or contaminated components (90);- providing and activating an effluent treatment device (60);- providing and activating a fluid suction device (70) communicating with the internal volume (V) of said container (10) and with said effluent treatment device (60).

8. Process according to claim 7, wherein after said segmentation action, said inflatable joint (50) is deactivated and the closure element (20) is subsequently moved so as to achieve the operating opening configuration of the container (10).

9. Process according to claim 7 or 8, wherein said cutting device (40) is configured to operate by an abrasive water jet.

10. Process according to claim 9, wherein an amount of water equal to 115 I and an amount of corundum equal to 16 kg are used to carry out said segmentation action of each activated and / or contaminated component.

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