JP6075967B2 - Shield protection tent assembly - Google Patents

Description

  The present invention relates to a tent assembly used in the field of handling nuclear material. In particular, the present invention relates to nuclear radiation protection and disposable tent assemblies used to perform intervention on radioactively contaminated articles, such as glove boxes, so that the intervention can be performed in a leak-proof environment. It has become. The tent assembly includes at least one leak-proof envelope and an outer support. Such interventions include, for example, the dismantling of nuclear facilities and large-scale maintenance.

  At nuclear facilities, at some point during the lifetime of these nuclear facilities, the nuclear facilities are usually prepared with the risk of radioactive material release and exposure to alpha, beta and / or gamma rays and / or neutrons. Open intervention is required.

  Nuclear facilities, such as mixed oxide (“MOX”) or other plutonium-containing fuel molding processing manufacturing plants, for example, contaminated glove boxes, spent fuel reprocessing for the production of new fuels containing minor actinides Contains β / γ cells and α / β / γ cells.

  One such intervention is the decommissioing of nuclear facilities. The decommissioning is performed entirely in connection with, for example, a shutdown of the nuclear facility or when a part of the nuclear facility needs to be modified, for example, or in extending the life of the nuclear facility.

  Large-scale maintenance is another intervention that opens nuclear facilities in preparation for the risk of pollutant emissions. For example, replacement of large or heavy process articles or windows may be associated with disposal and crushing of process articles and disassembly of contaminated nuclear process enclosures.

  During the intervention, for example during decommissioning and large-scale maintenance, many precautions have been taken to reduce the release of radioactively contaminated particles and the risk of human exposure to them. As an operator, humans can use internal exposure and radiation as a result of digestion and inhalation of these radioactively contaminated particles, for example, external exposure and / or ALARA (" As Low As Reasonably Achievable ”needs to be protected from both external exposure according to“ low as reasonably achievable ”). Thus, prior to intervention, nuclear material and fissile material are typically collected and removed from nuclear material, so that exposure to fissile neutrons is typically negligible. Next, decontamination up to the maximum allowable dose may be performed. Another precaution is the installation of interventional enclosures such as alpha-stopped cells, glove boxes or disposable protective tent assemblies around nuclear facilities to be disassembled or serviced.

  When an alpha stop cell or glove box is used as an intervention enclosure, a nuclear facility, for example, a glove box, must first be brought into this enclosure installed elsewhere in the plant . However, this transportation is costly and dangerous when considering exposure to radioactive particles.

  Placing the nuclear facility in the enclosure is done using conventional “bag-in” technology. This bag-in technique allows the introduction of equipment or other objects while maintaining enclosure containment. For this purpose, the device or object is placed in a bag, and an O-ring is provided on the open side of the bag. The O-ring is then secured in a groove provided around the access port of the enclosure, thereby overlapping with another bag already present at the access port and closing this other bag. To introduce the device or object, the device or object is pulled with the bag positioned within the enclosure. Once the device or object is located inside, the access port is closed by the bag containing the device or object.

  The enclosure contains equipment necessary for intervention in a leak-proof state with respect to the external environment. The operation of an electrical or pneumatic assist tool, such as a disassembly tool, is performed by a human being as an operator standing either inside the alpha stop cell or outside the cutting box. Operator entry and exit is expected to take place via a suitable airlock, while removal of waste pieces resulting from the cutting operation uses a waste drum coupled to an alpha stop cell or cutting box. Is realized.

  When working in the alpha stop cell, the operator is equipped with leak-proof clothing as well as a breathing apparatus. Lead aprons should be worn when exposure to gamma radiation is likely.

  In order to avoid transporting nuclear facilities to off-site facilities and to avoid the associated costs and exposure risks, the use of protective tent assemblies is described, for example, in DE 40 40 115 and R. Baumann ( R. BAUMANN), P. FABER, “Dismantling Techniques for Plutonium- Dismantling Techniques for Plutonium- Contaminated Glove-boxes: Experience from First Year of Decommissioning ”, 6th International Symposium of Radioactive & Decommissioning Wastes, Kontec 2004, Berlin ,Germany , March 2004.

  The latter technical document describes how the glove box is transported towards the protective tent assembly installed in the work facility and how the protective tent assembly is erected around the glove box in the field. Is described. The protective tent assembly includes a flexible or flexible leak-proof envelope made to fit the size and shape of the glove box to be disassembled, the protective tent assembly may comprise a glove and a window, and It should be maintained in a vacuum by its own ventilation system. The tent assembly may contain a cutting device for performing disassembly work in a state isolated from the external environment. The operation of the disassembly tool is performed by an operator standing outside the protective tent assembly. These operators may be equipped with tools and monitoring devices similar to those used while operating the process glove box. Waste resulting from the cutting operation may be discharged through a waste drum coupled in a leaktight manner to the protective tent assembly.

A disadvantage of the known protective tent assembly is that it provides insufficient radiation protection for humans as operators. Certainly, the fear of exposure to β and γ radiation by U / Pu and Am ²⁴¹ resulting from Pu ²⁴¹ decay and especially to neutrons resulting from nuclear reactions in most nuclear facilities is underestimated. Should not.

  Thus, if the process equipment to be disassembled or serviced and its enclosure is highly contaminated, the operator is now protected from exposure by wearing appropriate clothing containing the state of the art lead apron.

German Patent Application No. 40401115

R. BAUMANN, P. FABER, "Dismantling Technics for Protonium-Contaminated Glovebox: Experience from First Year of Decoration (Dismantling) Techniques for Plutonium-Contaminated Glove-boxes: Experience from First Year of Decommissioning ”, 6th International Symposium of Radioactive & Decommissioning Wastes, Kontec 2004, Berlin, Germany, March 2004

  However, the lead apron has the disadvantage that it does not reduce the neutron dose rate for the operator wearing it, but only protects against gamma rays. In addition, these lead aprons are heavy and limit operator flexibility, thus burdening the operator with additional burdens and physically consuming and dangerous cutting operations in known protective tent assemblies.

  An object of the present invention is to provide a protective tent assembly that protects a human being as an operator so as not to be exposed to neutrons and α-rays and γ-rays, and provides a protective tent assembly that enables safe operation of a nuclear facility. There is to do.

  The nuclear radiation protection tent assembly of the present invention further includes an outer shielding panel arranged to be disposed around the envelope, wherein the shielding panel is accessible to the interior space of the envelope by at least one access opening. At least one additional access opening to allow the panel to be provided to shield the operator from nuclear radiation, the outer support being provided with means for holding the shielding panel . The shielding panel protects the operator from radiation, such as alpha rays, neutron rays and gamma rays, for example when nuclear or radioactive material is present in the envelope and can escape from the envelope. By providing another access opening in the envelope for operator intervention, the operator's access to the interior of the tent assembly is not limited despite the presence of the shielding panel. Advantageously, these access openings are leak-proof ports that allow access to the interior of the tent assembly in a leak-proof condition, thereby minimizing the risk of radiation exposure.

  Advantageously, the shielding panel is made of a transparent material that can be seen in the envelope and can be illuminated for entry into the volume defined by the envelope.

  Since the outer metal support of the protective tent assembly includes means for holding the shield panel, the shield panel can be secured to the outer metal support. In this way, the operator benefits from the freedom of movement because he does not have to hold the panel himself, for example by hand, and the operator uses his limbs to hold the panel. It is not feasible if necessary.

  Advantageously, the shielding panel is removably attached to the outer support so that the shielding panel can be reused in a safe manner. This is because the shielding panel means that the contaminants remain inside the envelope and therefore cannot be contaminated outside. Certainly, the protective tent assembly of the present invention creates a leak-proof environment around the nuclear facility, which is, for example, radiated during an intervention in which the nuclear facility is opened intentionally or otherwise. This is useful because it minimizes the risk of releasing active and contaminated particles.

  Advantageously, the shielding panel is mounted to face the outside of the envelope so that it does not become contaminated during the intervention so that the panel can be reused. Indeed, a shielding panel with an access opening according to the present invention can be attached to the outer support during the intervention and can be removed again from the outer support once the intervention is complete. The envelope is generally disposable, but the shielding panel and outer support can be regenerated and reused several times before disposal. This is because the shielding panel and the outer support are not contaminated because they are located outside the leak-proof envelope. This substantially reduces secondary waste. As a result, waste disposal costs are significantly reduced compared to the prior art, yet shielding against alpha, neutron and gamma rays is still provided.

  Thus, the amount of secondary waste is reduced as a result of the use of the protective tent assembly of the present invention. This is because the outer parts, i.e. the outer support and the outer shielding panel, can be reused several times. Disposal of radioactively contaminated waste (suspected of being contaminated with radioactivity) is a major concern for plants that contain nuclear equipment because it is extremely expensive. Thus, safe disposal of the protective tent assembly shield panel and outer support substantially reduces waste disposal costs.

  The present invention is also a method for safe operation of at least a radioactive article, comprising providing a protective tent assembly of the present invention having a transparent shielding panel around the radioactive article, and operating the radioactive article. It is related with the method characterized by having.

  Other details and specific features of the invention will become apparent from the appended claims and the following description.

It is a figure which shows the conventional glove box for handling a radioactive substance. FIG. 2 shows a protective tent assembly as an embodiment of the present invention with an outer metal support disposed around a glove box similar to the glove box of FIG. 1 and having a leakproof envelope attached thereto. FIG. 3 shows details of the protective tent assembly of FIG. 2 including means for holding the outer transparent shielding panel attached to the outer support. FIG. 3 is a cross-sectional view of the protective tent assembly and glove box of FIG. 2.

  In the figures, the same reference numerals are assigned to the same or similar elements.

  In the context of the present invention, what is to be understood by "alpha tight" or "leak tight" is not necessarily absolute leakproof, but gas, liquid and This means that the permeability to dust is below the maximum allowable level known to the skilled worker with respect to the intended intervention, for example the manipulation of radioactive material. In the context of the present invention, the state of “alpha-stopping” or “leakage-proofing” is achieved when the pressure in the leakage-proof envelope is reduced to 100-200 Pa relative to atmospheric pressure, ie when a vacuum is applied. Possible and hermeticity is on the order of 0.1% by volume per hour.

  FIG. 1 shows a conventional glove box 1 and an operator 2. The illustrated glove box is a single glove box. However, it is clear that a plurality of glove boxes can be connected to each other, and thus the present invention can be utilized not only for the use of a single glove box tent assembly, but also for a plurality of glove boxes. It can also be used for the use of tent assemblies. A glove box is the most frequently used type of containment enclosure used in fuel cycle equipment on a laboratory, pilot or industrial scale in the nuclear industry. Normally, glove boxes are designed for work or maintenance when human intervention is required. Most of the walls of the glove box are transparent or have windows. The glove box further includes a glove port 3 that allows manual operation and other access ports that provide utilities such as ventilation, electrical wiring, gas piping, and the like.

  FIG. 2 shows a protective tent assembly as an embodiment of the present invention installed around the glove box 1 to isolate the glove box 1 (shown in dotted lines) prior to disassembly or other intervention. 10 is shown. The tent assembly includes at least one leakproof envelope 4 and an outer support 11. The envelope is formed of at least one flexible or soft sheet with at least one access opening 15 that allows entry into the volume defined by the envelope. The access opening preferably comprises a glove to maintain leak tightness. The envelope is attached to the outer support 11 by a strap 12, for example. A waste outlet 5 is provided in the leak-proof envelope, the purpose of which is to discharge objects or equipment that have been treated in the leak-proof envelope. The envelope preferably further comprises a window 8 so that the inside of the envelope can be seen and light can enter the envelope.

  The protective tent assembly 10 of the present invention is not limited to a particular size and shape. The shape is determined by the volume that needs to be leakproof to provide sufficient freedom of movement for the operator 2. This is particularly beneficial during the performance of operations to be performed within the protective tent assembly. The dimensions of the protective tent assembly of the present invention are selected to match the dimensions of the nuclear facility to be disassembled. For this purpose, the flexible sheet forming the leak-proof envelope 4 may be formed by joining a set of sheets in a standard format or a custom format. For example, to form the leakproof envelope 4 of the tent assembly 10, the flexible sheet is placed on the floor of the room where the disassembly operation is performed or on a table placed in a similar room. If the protective tent assembly 10 is to be installed on a stand, the protective tent assembly may differ from the illustrated protective tent assembly in that the orientation of the waste outlet connection 5 is different. That is, the waste outlet connector 5 may be directed downward to facilitate waste collection.

  After the flexible envelope of the leak-proof envelope is in place, the glove box 1 is moved within the volume defined by the envelope. This is done by lifting, moving and lowering the glove box 1 onto the bottom, for example by using a lifting device or rolling the glove box 1 until it is installed in the volume defined by the envelope. Can be achieved. Protective elements may be provided on the flexible sheet and / or its edges to provide protection from mechanical damage that may be caused by glove box positioning. The material of the envelope 4 is preferably non-flame propagating. In particular, the envelope may consist of a foil of PES (polyether sulfone) coated with PVC (polyvinyl chloride).

  In addition, the flexible envelope allows the protective envelope to be folded compactly. Thus, the protective envelope can be folded, for example in a rolled state, for example for easy handling or easy storage before or after use. The protective envelope can also be folded to fit within a waste container, for example for safe disposal after use.

  Leak tightness is achieved, for example, by hermeticity at a leak rate of 0.1% by volume per hour and for example by reducing the pressure in the envelope by 100-200 Pa relative to ambient pressure. The degree of leakage achieved within the protective envelope depends, for example, on the hardness of the flexible sheet and the number and type of access openings and ports. Provided by forming a leak-proof envelope with one or more flexible sheets, usually by welding the sheet edges together to provide a suitable leak-proof space around the glove box. .

  The envelope preferably further comprises one or more access ports (not shown), the access port preferably being a leak-proof interface between the interior and exterior of the envelope and advantageously A leak-proof port, for example an air lock, can be constructed. By providing one or more access ports, it is possible to provide a device that can provide assistance during operations performed within the envelope without compromising the leak-proof nature of the envelope. These access ports are preferably leak-proof access ports. For example, a power outlet, a monitoring device, an emergency fire extinguishing device such as a robot arm for remote control operation, a ventilation pipe or the like may be coupled to the leak-proof envelope in a leak-proof manner to meet this purpose. For example, waste containers may also be leak-tightly coupled to the leak-proof envelope for the discharge of waste resulting from the disassembly operation. Also, for example, equipment or tools required for disassembly work may be provided in or removed from the envelope in a leak-proof manner through one of the leak-proof ports. In certain embodiments, the access port is a glove port, such that one or more gloves or one or more pairs of gloves allow manual action within the envelope 4. It is attached to the glove port in a leaktight state.

  When disassembling a glove box 1, for example a Pu-contaminated glove box, or carrying out extensive maintenance on it, the operator 2 may derive from residual contaminants in the glove box by providing a protective leak-proof envelope. Shielded from γ rays and / or neutron rays.

  The protective tent assembly 10 further includes at least one outer shielding panel 7 provided to shield the operator from nuclear radiation. Indeed, shielding panels reduce the nuclear radiation dose rate. The shielding panel 7 is preferably formed by a set of panels attached along the circumference of the envelope 4. These panels are attached to the support 1 and the envelope 4 is also attached to this support. Furthermore, at least one of these shielding panels 7 is provided so that the operator 2 can reach the access opening 15 of the envelope 4 from the outside of the tent assembly and then reach the opening 3 of the glove box. Some have two separate access openings 9. In this way, the operator 2 can gain access to the interior of the tent assembly and glove box and can manipulate the handling and disassembly tools and perform interventions. The pitch between the access openings is selected to be ergonomic in both the vertical and horizontal directions. The diameter of the access opening is generally 150-250 mm so that a human arm can pass through.

  In a particular embodiment, the shielding panel 7 protects the operator from both gamma rays and / or neutron rays. The shielding panel 7 may be modular and convenient and easy to handle. The shielding panel 7 can also be reused in the protective tent assembly located in succession, which is economical. In certain embodiments, the shielding panel 7 comprises a material selected from leaded methyl polymethacrylate (eg, Plexiglas ™), leaded glass, and leaded polycarbonate, the material comprising a plate Or it has a sandwich structure. Leaded plexiglas provides protection from gamma rays and neutrons. Leaded glass provides protection from gamma rays. Leaded glass containing a layer of polycarbonate provides protection from gamma rays and neutrons. Furthermore, the example of leaded glass with such a polycarbonate layer provides additional mechanical operator protection from mechanical parabodies, for example in the event of an earthquake. The shielding panel 7 is preferably transparent so that it can be easily seen through the panel. As a variant, if the panel is not made of a transparent material, a window may be provided in the panel.

  In a particular embodiment, the shielding panel 7 is modular. The modularity of the shielding panel and support 11 makes it easy to disassemble the protective tent assembly after use, store the modular parts until the next use, and reconstruct the protective tent assembly when needed is there. In certain embodiments, the shielding panel 7 is reusable in subsequent applications that require the use of the protective tent assembly 10. The reason that the shielding panel is reusable is that it is not contaminated or can be decontaminated after operation when placed outside the envelope 4. Further, the reason that the shielding panel 7 is reusable is that the shielding panel is removed from the outer support 11 after operation and reattached to the outer support 11 for the next operation requiring the use of the protective tent assembly 10. Because it can. By reusing the shielding panel during the next operation, the amount of secondary nuclear waste is reduced and the disposal cost of nuclear waste is reduced.

  Nevertheless, in addition to the waste generated due to the envelope 4 and the outer support 11, the shielding panel 7 can be used when it is necessary to be discarded after continuous use, despite being reusable. Will increase the amount of secondary nuclear waste. Whether the shielding panel 7 is uncontaminated or can be decontaminated after operation, the shielding panel 7 is considered a dangerous industrial waste in view of these heavy metal (Pb) contents. Nevertheless, the protective tent assembly of the present invention limits the amount of secondary waste. This is because both the outer metal support 11 and the shielding panel 7 can be reused several times after each intervention, thereby substantially reducing disposal costs.

  The thickness of the shielding panel 7 is selected to be 8 to 48 mm, preferably 12 to 40 mm, and more preferably 24 mm. It is not recommended to be thinner than 8 mm. This is because the shielding panel may not provide sufficient radiation protection or mechanical stability. It is not preferable that it is thicker than 48 mm. This is because the shielding panel is too heavy, too expensive, or may be less transparent. Plexiglas is generally available in 12 mm or more. A 24 mm shielding panel is preferred, for example, when standard, commonly available leaded plexiglass is used.

The width and height of the shielding panel 7 can be set with special specifications, but are generally 400-1500 mm, and the resulting surface area is 0.4-1.5 m ² , especially 0.5-1.0 m. ² .

  2 and 3 also show how the outer support 11 is arranged around the envelope 4. The support is preferably a metal support, but it will be apparent that other materials such as epoxy reinforced with carbon or fibers can be used. Materials that are reusable in constructing the support are preferred. This is because the support can be reused, thereby limiting the amount of waste produced. The support 11 is configured to hold the envelope 4 by, for example, a strap 12 connected to the flexible sheet of the envelope 4 in order to avoid the collapse of the flexible envelope 4 under vacuum. The support is also provided for attaching the shielding panel 7 to the support, for example by means of a fixture 13. The mechanical fixture 13 allows both the shielding panel and the outer frame part to be reused. The external support 11 is preferably designed as a frame made of bars 14 so as not to impair the operator's access to the work.

  The support 11 provides a structural multi-purpose backbone for the protective tent assembly 10 of the present invention. Advantageously, the support 11 is an outer support that can be reused after the contaminated envelope has been discarded after use. However, those skilled in the art can consider using the inner support separately depending on the environment, for example, when the available space is limited. Advantageously, the outer support is a metallic support that can be reused several times. This is because the support is generally protected from contamination by nuclear material. However, when discarding the outer support, the metal can advantageously trap contaminating particles during waste incineration.

  The support 11 may also be used to handle mechanical forces and / or eg heavy parts resulting from the vacuum maintained in the envelope during operation or operator intervention, eg the weight of the operator 2 climbing on the support 11. It is designed to withstand mechanical forces transmitted by devices such as pulley devices installed in the envelope 4. As with the envelope 4, this support 11 may be manufactured using standardization or specification elements using a material that facilitates its maintenance and handling, for example a metallic material, for example aluminum. In certain embodiments, the support is earthquake resistant. In another special embodiment, the outer metal support 11 is modular, made of frame parts, or reusable in a protective tent assembly located in series.

  After disassembly or other use of the associated glove box, the protective tent assembly is disposed of. For example, the empty Pu contamination envelope 4 and its globe and window are wound and cut, thereby reducing its volume and disassembling the outer metal support to be considered waste. This is because the outer metal support has some limited spot contamination on the part of the frame that cannot be wiped or cleaned (eg hollow parts, screw holes, recessed corners). This is because of doubt. A known process for removing the metal support in an efficient manner is to dissolve the metal support 11 to separate potentially contaminated parts from uncontaminated metal. Thus, both envelope 4 and outer support 11 are considered nuclear waste and are referred to as secondary waste (by distinction from primary waste derived from the decomposed / maintained glove box itself). . Discarding secondary waste is not only costly, but adds an additional burden to the environment.

  FIG. 4 shows how the bolt 11 is provided on the support 11 for the shielding panel 7. The support 11 may further comprise an attachment for placing the pulley device in the envelope 4. The panel 7 is mechanically attached to the outer metal support 11 to obtain appropriate stability and mechanical resistance against contact with the operator. In certain embodiments, the outer metal support 11 is modular or made of frame parts that are convenient and easy to handle. The outer metal support 11 may also be reusable with a protective tent assembly located in series, which is economical.

  In certain embodiments, the envelope access opening 15, another access opening 9 in the panel, and the envelope access port allow the operator 2 to view the tent assembly and place limbs therein. Dimensions are determined. This allows safe, flexible, quick and economical work. The envelope access opening 15 and the panel another access opening 9 are aligned with each other to allow easy passage from one access opening to another.

  In certain embodiments, the protective tent assembly of the present invention can be used to decommission a medium sized MOX fuel production plant.

  The protective tent assembly can be configured to further include at least one device within the leakproof envelope. In particular, the at least one device may comprise a pulley device connected to the support.

  The shape of the protective tent assembly 10 is, for example, one parallelepiped or a plurality of parallelepipeds. The protective tent assembly 10 surrounds the glove box 1 when the contaminated object is disassembled in the glove box or when the glove box itself is disassembled. The overall dimensions (height, width, length) of the tent assembly 10 are matched to the overall dimensions of the glove box 1 to be disassembled and work between the inside of the tent assembly and the outside of the glove box wall. Selected to provide distance. This working distance is a product of compromise, i.e. a short distance makes it easier for the operator to put his gloved hand inside the glove box, and a long distance makes the operator close to the glove box. Pneumatic assist tools (eg, jigsaws, punch cutting tools ...) can be handled and manipulated to disassemble the enclosure. Therefore, the working distance is usually selected from 200 to 450 mm.

  Although the invention has been described in terms of particular exemplary embodiments, it will be apparent that various modifications and changes can be made to these embodiments without departing from the broad scope of the invention as set forth in the claims. I will. For example, the protective tent assembly and radioactive article handling method of the present invention can be used to handle other articles other than nuclear enclosures and for purposes other than the purpose of disassembling these nuclear enclosures. For example, such a protective tent assembly can also be used to handle aggressive chemicals, biological radioactive materials, and the like.

  In the first example where the protective tent assembly was used for disassembly of the glove box, the glove box had a height of 2100 mm, a length of 2500 mm and a width of 1000 mm. In contrast, a protective tent assembly having a height of 2400 mm, a length of 4000 mm and a width of 1400 mm and having a sheet composition of PVC-coated PES was prepared so that it encloses the glove box. The outer transparent shielding panel was attached to the outer metal support of the tent assembly.

  The shielding panel was made of leaded plexiglas having a thickness of 24 mm and a dose rate reduction factor of 7 alpha, gamma and neutrons. Decomposition was realized using a vacuum of 200 Pa with a dose rate of 100 μSv / h of the overall gamma ray + neutron ray of the glove box at the time of contact.

DESCRIPTION OF SYMBOLS 1 Glove box 3 Glove port 4 Leak-proof envelope 5 Waste outlet connection part 7 Shielding panel 8 Window 9,15 Access opening part 10 Protection tent assembly 11 Outer support body 12 Strap

Claims (16)

A nuclear radiation protection tent assembly comprising:
A glove box with an opening ,
A leak-proof envelope surrounding the glove box , wherein the envelope is formed of at least one flexible sheet with at least one access opening aligned with at least one opening of the glove box ; further,
A plurality of straps configured to connect to the at least one flexible sheet of the leak-proof envelope;
An outer support , wherein the envelope is attached to the outer support by the plurality of straps;
At least one outer shielding panel configured to shield against nuclear radiation, the at least one outer shielding panel being at least one other aligned with the at least one access opening of the leak-proof envelope. With an access opening,
A tent assembly comprising mechanical attachment means provided on the outer support to which each of the outer shielding panels is attached . The leaktight envelope is welded several flexible sheet is formed by, claim 1 Symbol placement tent assembly. The tent assembly according to claim 1 or 2 , wherein each outer shielding panel is removably attached to the outer support. The tent assembly according to any one of claims 1 to 3 , wherein the at least one outer shielding panel is made of a transparent material. At least one outer shielding panel has at least one window to provide visualization inside the volume defined by the shielding panel, tent assembly according to any one of claims 1-3. The tent assembly according to any one of claims 1 to 5 , wherein the thickness of the at least one outer shielding panel ranges from 8 mm to 48 mm . The tent assembly according to any one of claims 1 to 6, wherein the thickness of the at least one outer shielding panel ranges from 12mm to 40mm. The tent assembly according to any one of claims 1 to 7, wherein the thickness of the at least one outer shielding panel is 24 mm. Both height and width of the at least one shielding panels is 400 mm ~1500mm, surface area obtained as a result is a 0.5 m ² ~1.5m ^2, any one of claims 1-8 A tent assembly according to any one of the above. Said outer support Ri Oh modular metal frame formed by the frame parts, at least one frame part including the mechanical fixture means, tent according to any one of claims 1-9 Assembly. Wherein the diameter of the further access opening of the at least one shielding panels is in the range of 150 mm ~250mm, tent assembly according to any one of claims 1-10. Wherein said at least one shielding panels, leaded methyl polymethacrylate, Ru is composed of a material selected from the leaded glass and leaded polycarbonate, tent assembly according to any one of claims 1 to 11. The tent assembly according to any one of the preceding claims, wherein the at least one shielding panel has a plate structure or a sandwich structure. 12. A tent assembly according to any one of the preceding claims, wherein the at least one access opening is a leak-proof port. The tent assembly according to any one of claims 1 to 12, wherein the envelope is under vacuum. 14. A tent assembly according to any one of the preceding claims, wherein a waste outlet is provided in the leakproof envelope.