NEUTRON SHIELDING DEVICE AND SYSTEM

Description

[0001] The invention relates to a neutron shielding device with channels and a system with the neutron shielding device.

[0002] A neutron shielding device can shield neutrons. Neutrons interact with the neutron shielding device and are thereby shielded.

[0003] A neutron shielding device can be a component of a neutron source. For example, the European Spallation Source (ESS) includes a neutron shielding device.

[0004] A neutron shielding device may comprise a plate. One or more channels may be milled into one side of the plate. On the side with the one or more channels, these channels may be closed by welded-on sheets. During operation, a cooling liquid may flow through the one or more channels to prevent the neutron shielding device from overheating. A neutron shielding device may comprise a plurality of such plates with channels and welded-on sheets that are stacked. Additional welds may connect two plates with the welded-on sheets.

[0005] Plates and sheets of the neutron shielding device can be made of steel, as steel is suitable for neutron shielding. Austenitic steel can be selected as the steel. Austenitic steel is a stainless steel with more than 8% nickel content and a face-centered cubic crystal structure.

[0006] A neutron shielding device constructed in this way can be exposed to strong mechanical stresses during operation, despite or precisely because of the cooling.

[0007] Document CN 210 073 342 U (SILICON LAKE COLLEGE) discloses a neutron shielding device comprising a steel plate and a layer on the plate, wherein one or more channels are present in the layer, wherein the one or more channels have at least one inlet and at least one outlet.

[0008] The invention aims to create a neutron shielding device that is well suited and stable for shielding neutrons.

[0009] This object is achieved by a neutron shielding device having the features of the first claim. The dependent claims relate to advantageous embodiments.

[0010] The invention relates to a neutron shielding device comprising a steel plate and a layer on the steel plate. A channel is present in the layer. There is an inlet and an outlet for the channel. A plurality of channels can be present in the layer. The channels can have a common inlet and a common outlet. There can be an inlet and an outlet for each channel. The layer can be made of a material that has better thermal conductivity than the steel plate. The thermal conductivity of the material from which the layer is formed can be at least twice the thermal conductivity of the steel. The thermal conductivity of the material from which the layer is formed can be at least five times or at least ten times the thermal conductivity of the steel.

[0011] Thermal conductivity indicates the heat flow through a 1 m² and 1 m thick layer of a material at a temperature difference of 1 Kelvin (K). The unit of thermal conductivity is W / (m*K).

[0012] For example, lead would be a well-suited material for neutron shielding. However, steel offers manufacturing advantages over lead. Furthermore, steel can serve as a support for other components that the neutron shielding device may include.

[0013] A plate is a flat component. A plate has two opposing surfaces that are large compared to adjacent surfaces of the plate. These two opposing surfaces of the plate can be parallel to each other. In this sense, a plate is several times longer and wider than it is high or thick. These two opposing surfaces can be flat, i.e., two-dimensional.

[0014] The layer can be made of aluminum, for example. "Aluminum layer" means that the material of the layer is predominantly aluminum. The layer can therefore also be made of an aluminum alloy.

[0015] Titanium, tungsten, or copper can be used instead of aluminum. Low-alloy materials made of aluminum, titanium, tungsten, or copper, such as CuCr1Zr, can also be used. In a low-alloy material made of aluminum, titanium, tungsten, or copper, the total content of alloying elements cannot exceed 5 wt. A nickel alloy such as Inconel ® can also be considered.

[0016] An aluminum layer on the plate means aluminum that is spread out over one of the large surfaces of the steel plate. An aluminum layer is several times longer and wider than it is high. Two opposite surfaces of the layer can be flat and / or parallel to each other, which are large compared to other surfaces of the layer. The aluminum layer can completely cover the surface of the steel plate, i.e. extend to the edge of the surface and be completely closed. The aluminum layer then covers 100% of the surface of the steel plate. The aluminum layer can cover at least 70%, at least 80%, or at least 90% of the surface of the steel plate. The same applies to the other materials that have been mentioned as alternatives to aluminum.

[0017] A channel in the layer of aluminum or an alternatively mentioned material is located within the layer, such that the cross-section of the channel is circumferential. The cross-section of the channel can be rectangular or circular, for example. The cross-section of the channel can be square.

[0018] A cooling fluid can flow into the channel through the inlet and out again through the channel's outlet. The layer containing one or more channels thus has a first, externally accessible opening and a second, externally accessible opening. One opening serves as the inlet, and the other as the outlet.

[0019] It has been found that a neutron shielding device constructed in this way is particularly well-suited to the thermally induced stresses that can occur during operation. This is especially true compared to a neutron shielding device with a steel plate and one or more channels located within the steel plate. A neutron shielding device according to the invention is therefore particularly stable and, thanks to the steel, well-suited for shielding neutrons.

[0020] The layer containing one or more channels is generally firmly bonded to the steel plate to enable good heat transfer between the layer and the plate. The layer containing one or more channels can be interlocked with the steel plate to enable good heat transfer between the layer and the plate.

[0021] The channel density is preferably very high in order to achieve a very good cooling effect. Preferably, an area that can be viewed as a cross-section through channels is formed by at least 40% or at least 50% of the channels when viewed from above. A web between two adjacent channels cannot be wider than the width of an adjacent channel when viewed from above if the area is to be formed by at least 50% channels when viewed from above. Each channel can, for example, be 15 mm to 30 mm wide. A web between two channels can then also be up to 30 mm wide, depending on the width of the one or more channels.

[0022] The one or more channels can be at least 15 mm or at least 25 mm high. The one or more channels can be at most 40 mm or at most 30 mm high.

[0023] The one or more channels preferably have a rectangular cross-section in order to be able to produce them technically easily, for example by milling.

[0024] A layer with channels can be attached to opposite sides of the steel plate, further improving stability.

[0025] The layer containing one or more channels can be thinner than the steel plate. This helps ensure that neutrons can be effectively shielded without requiring excessive material expenditure.

[0026] Between the layer containing one or more channels and the steel plate, there may be a first intermediate layer, which is generally thinner than the layer containing one or more channels. The first intermediate layer may directly adjoin the layer containing one or more channels on one side and / or the steel plate on the other side. This can be achieved, for example, by the intermediate layer enabling a particularly strong and intimate connection between the layer containing one or more channels and the steel plate.

[0027] A second intermediate layer may be present, for example, made of another metal. The second intermediate layer may be directly adjacent to the first intermediate layer on one side and / or to the steel plate on the other side.

[0028] An intermediate layer has no channels. An intermediate layer can be at least 0.5 mm or at least 1 mm thick. An intermediate layer can be a maximum of 5 mm or a maximum of 3 mm thick. An intermediate layer can be provided to improve heat transfer and / or the strength of the connection between the layer containing one or more channels and the steel plate.

[0029] Between the aluminum layer containing one or more channels and the steel plate, there can be an intermediate aluminum layer that has a higher aluminum content than the aluminum layer containing the channels. This helps to ensure that the steel plate can be connected particularly securely to the aluminum layer containing the channels. At least in the case of aluminum, this can help to create a strong connection and thus improve heat transfer between the aluminum layer containing one or more channels and the steel, and thus improve cooling.

[0030] For example, if the layer with one or more channels is made of copper, the intermediate layer can have a higher copper content than the copper layer with one or more channels. The same applies to other materials that are suitable as alternatives to aluminum.

[0031] The aluminum intermediate layer with the higher aluminum content can contain at least 90 wt.% and / or no more than 99.9 wt.% aluminum. The aluminum intermediate layer can, for example, consist of AI99.5 (EN AW-1050A), which has an aluminum content of 99.5 wt.%.

[0032] The aluminum intermediate layer with the higher aluminum content can be thinner than the aluminum layer with the channels within it. This helps keep material consumption to a minimum.

[0033] The aluminum intermediate layer with the higher aluminum content can be directly adjacent to the aluminum layer with the channels within it. This creates direct contact between the aluminum intermediate layer with the higher aluminum content and the aluminum layer with one or more channels within it. This helps keep material consumption to a minimum.

[0034] A titanium intermediate layer can be placed between the aluminum intermediate layer with the higher aluminum content and the steel plate. This contributes to a more stable connection between the steel plate and the aluminum layer with its channels. This can further improve heat transfer and thus cooling.

[0035] The titanium intermediate layer can be thinner than the aluminum intermediate layer with its higher aluminum content. This further reduces material consumption.

[0036] The titanium intermediate layer can be directly adjacent to the aluminum intermediate layer with the higher aluminum content. The titanium intermediate layer can be directly adjacent to the steel plate. This further improves material consumption and minimizes the required amount of material.

[0037] If the plate and the layer with the one or more channels therein are interlocked, and there are one or more intermediate layers, then the plate and the layer are indirectly interlocked. A first intermediate layer can then be interlocked with the layer with the channels therein. The first intermediate layer can then be interlocked with the plate or with a second intermediate layer. The second intermediate layer can be interlocked with the plate.

[0038] The steel of the plate can be austenitic steel, which can further improve neutron shielding. The steel of the plate can be martensitic steel, which is also well suited.

[0039] The neutron shielding device can be a support for a neutron moderator and / or a neutron reflector. A steel plate can be provided for this purpose. The neutron shielding device can be an elongated body with, for example, a built-in neutron reflector and / or a built-in neutron moderator.

[0040] The shielding device can comprise a second steel plate. One or more cooling channels can be incorporated into one side of the second steel plate. The first plate can be joined to the second plate by explosive bonding such that the two plates are interlocked and the one or more channels are then located within the two plates. There is then at least one inlet and one outlet for the one or more channels. The fact that a shielding device can comprise two metal plates so that one or more cooling channels are located within the plates independently achieves the object of the invention. It is therefore not necessarily necessary to additionally provide a layer with channels therein in order to achieve the object of the invention.

[0041] The invention also relates to a system comprising a neutron source and a neutron shielding device. The neutron shielding device can be designed as described above. The neutron shielding device can be pushed into a device comprising the neutron source. The system then comprises a slide-in unit for the neutron shielding device. After being pushed in, the neutron shielding device can be brought into its final position by a further movement. If the neutron shielding device comprises a neutron reflector and / or a neutron moderator, the neutron reflector and / or neutron moderator are arranged such that the neutron reflector and / or the neutron moderator are not shielded from the neutrons by the neutron shielding device. Neutrons from the neutron source can therefore be directed onto the neutron reflector or neutron moderator.hit the neutron moderator without having to pass through the neutron shielding device.

[0042] In addition to the neutron shielding device, the system may include shielding bricks that also contribute to shielding neutrons. Shielding bricks can be blocks made of lead or steel. Shielding bricks can also include channels through which a cooling liquid can flow for cooling. A shielding brick is not necessarily permanently connected to the neutron shielding device. A shielding brick is generally not connected to the neutron shielding device by welding or explosive bonding. Shielding bricks and neutron shielding device can provide neutron shielding that is more than 1 m or more than 2 m thick in total. This also means that the neutron shielding device can be less than 1 m thick.

[0043] The system may include a nuclear reactor or a research reactor. A spallation neutron source may also be included in the system.

[0044] The invention also relates to a method for producing a neutron shielding device. The method may comprise applying the layer with the one or more channels therein by pressure. The layers and intermediate layers may be interlocked with one another. The layer with the one or more channels therein may then be suitably intimately bonded to the steel plate to enable very good heat transfer and bond strength.

[0045] To improve bonding, an intermediate layer made of, for example, aluminum and / or an intermediate layer made of, for example, titanium can be provided between the layer with the one or more channels and the steel plate. The intermediate layer made of aluminum has a higher aluminum content compared to the aluminum content of the layer with the one or more channels.

[0046] Before joining, the one or more channels can be filled by pressure with a high-strength material whose melting point is lower than that of the aluminum. This can better ensure that the one or more channels are preserved. After joining, the metal in the channels can be annealed and thus removed from the channels. The metal can, for example, consist at least predominantly of lead or tin.

[0047] A sheet made of aluminum or copper, for example, can have one or more channels on one side, which have been milled into the sheet, for example. After filling it with a low-melting metal, a sheet made of aluminum or copper, for example, can be placed on the surface to close the channels. The applied sheet can be secured, for example, by welding.

[0048] The layer with the one or more channels contained within it can be produced by milling one or more channels into the surface of a sheet made of aluminum, for example. A sheet of aluminum can then be attached, for example, by welding, to the surface into which the channels have been introduced to close the top of the channels.

[0049] They show: Figure 1: Section through a first neutron shielding device; Figure 2 : Section through a second neutron shielding device; Figure 3 : Section through a third neutron shielding device; Figure 4 : Section through a system with neutron shielding device.

[0050] The Figure 1 shows a section through a neutron shielding device 1 with a plate 2 made, for example, of steel. On the plate 2, there is a layer 3 containing several channels 4. Layer 3 can be made of aluminum.

[0051] Layer 3 with channels 4 in it can, as in the Figure 1 shown, be thinner than plate 2.

[0052] Between the layer 3 and the plate 2 there may be an intermediate layer 5, which may consist of aluminum. The intermediate layer 5 may have a higher aluminum content than the layer 3 with the channels 4 therein. The intermediate layer 5 may, as shown in the Figure 1 shown, be thinner than the layer 3 with the channels 4 therein. The intermediate layer 5 can, as shown in the Figure 1 shown, directly adjacent to layer 3 with the one or more channels 4 located therein.

[0053] Between the intermediate layer 5 and the plate 2 there may be a second intermediate layer 6. The second intermediate layer 6 may be made of titanium. The second intermediate layer 6 may, as shown in the Figure 1 shown, be thinner than the first intermediate layer 5. The second intermediate layer 6 can, as shown in the Figure 1 shown, directly adjacent to the first intermediate layer 5. The second intermediate layer 6 can, as shown in the Figure 1 shown, directly adjacent to plate 2.

[0054] The plate 2 and the second intermediate layer 6 can be interlocked. There is then, as in the Figure 1indicated, a zigzag-shaped surface 7 between the plate 2 and the second intermediate layer 6. The surface 7 can alternatively or additionally be wavy.

[0055] The first intermediate layer 5 and the second intermediate layer 6 can be interlocked. As shown in the Figure 1 indicated, there may be a wavy and / or zigzag-shaped surface 8 between the first intermediate layer 5 and the second intermediate layer 6.

[0056] The first intermediate layer 5 and the layer 3 with the channels 4 therein can be interlocked. As shown in the Figure 1 indicated, there may be a wavy and / or zigzag-shaped surface 9 between the first intermediate layer 5 and the layer 3 with the channels 4 therein.

[0057] In the Figure 2A section through a second neutron shielding device 1 with a plate 2 is shown. On both sides of the plate 2, there is a layer 3 in each case, in which one or more channels 4 are present. The thermal conductivity of the layer 3 with the one or more channels 4 can be at least twice as great or at least five times as great as the thermal conductivity of the existing plate 2.

[0058] In the Figure 3A section through a third neutron shielding device 1 is shown. This comprises three plates 2, which may be made of steel. Layers 3 containing one or more channels 4 are attached to both sides of the first and second plates 2 (as seen from above). The bottommost plate 2 has a layer 3 attached only to the underside, containing one or more channels 4. The topmost plate 2 may be thicker than the other two plates 2. Welded joints 10 may be present connecting opposing layers 3, or one plate 2 with an opposing layer 3, or even two plates 2.

[0059] The Figure 4shows a section through a system with a neutron source 11, a moderator 12, and a reflector 13. Neutrons from the neutron source 11 can first reach the moderator 12 and then the reflector 13. Cooled plates 2 of a neutron shielding device 1 can be located next to the moderator 12 and the reflector 13 behind it. Cooled plates 2 of the neutron shielding device 1 can be located behind the reflector 13. An inlet 14 and an outlet 15 can be present on the rear side. A cooling liquid can be introduced into the channels 4 via the inlet 14. The cooling liquid can flow out again through the outlet 15.

Claims

1. Neutron shielding device comprising a plate (2) consisting of steel and a layer on the plate (2), wherein in the layer (3) one or more channels (4) are present, said one or more channels (4) having at least one inlet (14) and at least one outlet (15), characterized in that the thermal conductivity of the layer (3) is at least twice as great or at least five times as great as the thermal conductivity of the plate (2) consisting of steel.

2. Neutron shielding device (1) according to the preceding claim, characterized in that the layer (3) with the one or more channels (4) consists of aluminum and / or a layer (3) consisting of aluminum and having channels (4) situated therein is present on opposite sides of the plate (2).

3. Neutron shielding device (1) according to the preceding claim, characterized in that an intermediate layer (5) made of aluminum is located between the layer (3) consisting of aluminum and the plate (2) consisting of steel, which intermediate layer (5) has a higher aluminum content than the layer (3) consisting of aluminum with the one or more channels (4) located therein.

4. Neutron shielding device (1) according to the preceding claim, characterized in that the aluminum content in the intermediate layer (5) has an aluminum content of at least 90% by weight and / or an aluminum content of not more than 99.9% by weight.

5. Neutron shielding device (1) according to one of the two preceding claims, characterized in that the intermediate layer (5) consisting of aluminum and having the higher aluminum content is thinner than the layer (3) with the one or more channels (4) located therein.

6. Neutron shielding device (1) according to one of the three preceding claims, characterized in that the intermediate layer (5) consisting of aluminum and having the higher aluminum content directly adjoins the layer (3) with the one or more channels (4) located therein.

7. Neutron shielding device (1) according to one of the four preceding claims, characterized in that an intermediate layer (6) consisting of titanium is located between the intermediate layer (5) consisting of aluminum and having the higher aluminum content and the plate (2) consisting of steel.

8. Neutron shielding device (1) according to the preceding claim, characterized in that the intermediate layer (6) consisting of titanium is thinner than the intermediate layer (5) consisting of aluminum and having the higher aluminum content.

9. Neutron shielding device (1) according to one of the two preceding claims, characterized in that the intermediate layer (6) consisting of titanium directly adjoins the intermediate layer (5) consisting of aluminum and having the higher aluminum content and / or in that the intermediate layer (6) consisting of titanium directly adjoins the plate (2) consisting of steel.

10. Neutron shielding device (1) according to one of the preceding claims, characterized in that the layer (3) with channels (4) located therein is thinner than the plate (2) consisting of steel.

11. Neutron shielding device (1) according to one of the preceding claims, characterized in that the steel of the plate (2) is an austenitic steel.

12. Neutron shielding device (1) according to one of the preceding claims, characterized in that the plate (2) and the layer (3) with the channels (4) located therein are interlocked or connected in a wave-like manner.

13. System comprising a neutron source and a neutron shielding device (1) according to one of the preceding claims for shielding neutrons from the neutron source (11).

14. System according to the preceding claim with a moderator (11) which is at least partially surrounded by the neutron shielding device (1).

15. System according to the preceding claim with a reflector (12) which is at least partially surrounded by the neutron shielding device (1).