Temporary storage container for actinide element oxides
By setting up a heat sink and a low-melting metal heat conducting medium in the actinide oxide temporary storage container, the heat accumulation problem caused by high decay heat of the oxide is solved, and safer temporary storage and retrieval of radioactive substances is achieved.
Patent Information
- Application Number
- CN202411049779.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-01
- Publication Date
- 2024-12-20
AI Technical Summary
The high decay heat and low thermal conductivity of actinide-based oxides lead to the accumulation of heat in the container, which may cause pressure boosting, leakage of radioactive substances and self-sintering of oxides, making it difficult to ensure the safety of future retrieval and reuse.
Design an actinide-based oxide temporary storage container, by setting a heat sink on each layer of oxide and filling the low-melting metal heat conducting medium between the outer and the containers, the heat dissipation effect is enhanced, and the stainless steel material and the outer shape of the outer, The content container structure forms a thermal conduction path to decay heat.
It effectively improves the heat dissipation performance of oxides, avoids pressure boosting and leakage of radioactive substances caused by heat accumulation, and ensures the safety of the container and the feasibility of future retrieval and reuse.
Smart Images
Figure CN119170313A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of spent fuel post-processing, and in particular relates to a temporary storage container for actinide oxides. Background Art
[0002] Among the high-level waste liquids produced by spent fuel reprocessing, americium and curium are the most toxic minor actinides that deserve the most attention. If they can be made into isotope products, or made into targets for transmutation, or enter the fast reactor fuel cycle system, their long-term hazards can be reduced or even eliminated. Unfortunately, neither the transmutation technology nor the fast reactor fuel cycle technology is mature at present, the market demand for americium and curium isotopes is very small, and the production technology is also immature. Therefore, it is possible to consider temporarily storing waste or product bodies containing americium and curium for a period of time, and then retrieving and reusing them after the relevant technology matures.
[0003] Due to the stable chemical properties of actinide oxides, uranium products, plutonium products, neptunium products, and MOX products are often temporarily stored in the form of oxides. Therefore, it is also possible to consider preparing the waste liquid containing americium and curium into mixed oxides for temporary storage. However, the decay heat of some isotopes of americium and curium is very high and the decay rate is slow, which causes the thermal power density of the americium-curium mixed oxide product to remain at a high level for a long time. This is the biggest difference between americium-curium mixed oxide and uranium, plutonium, and neptunium products, and it is also the biggest challenge faced by the design and processing of product containers and the heat management during the product storage stage. If a plutonium product container is used, such as Figure 1 As shown, when storing mixed oxides of americium and curium, since the inner container and the outer container are only in contact at the bottom, the thermal conductivity of the gas between the inner and outer containers is much lower than that of metal, and the decay heat in the inner container cannot be effectively discharged, which will definitely cause heat accumulation. Heat accumulation may cause the temperature in the center area of the oxide product to approach or even exceed 1000°C, which will not only cause the internal pressure of the product container to increase seriously, or even exceed the pressure limit of the product container, thereby causing leakage of radioactive materials, but may also cause a certain degree of self-sintering of the oxide in the high-temperature area, making it difficult to retrieve and reuse in the future. Summary of the invention
[0004] In view of the defects existing in the prior art, the object of the present invention is to provide an actinide oxide temporary storage container to enhance the heat dissipation effect of the container.
[0005] To achieve the above purpose, the technical solution adopted by the present invention is: an actinide oxide temporary storage container includes an outer container and an inner container, the inner container is located in the outer container, the actinide oxides are layered in the inner container along the height direction, each layer of actinide oxides is provided with a heat sink, and each layer of actinide oxides is in a compacted state.
[0006] Furthermore, the outer container is fitted with the inner container, wherein the thickness of the side wall of the inner container gradually decreases from top to bottom along the height direction, and the thickness of the side wall of the outer container gradually increases from top to bottom along the height direction.
[0007] Furthermore, there is a gap between the outer container and the inner container, and the gap is filled with a heat-conducting medium.
[0008] Furthermore, the heat conducting medium is a low melting point metal.
[0009] Furthermore, the gap between the outer container and the inner container is 2.5 mm-3.5 mm.
[0010] Furthermore, the inner container is also filled with an inert gas.
[0011] Furthermore, the outer container is provided with an outer cover for closing or opening the outer container, and the inner container is provided with an inner cover for closing or opening the inner container.
[0012] Furthermore, the bottom of the outer container is in an arc shape that is concave toward the center, and the bottom of the inner container is adapted to the outer container.
[0013] Furthermore, there are multiple inner containers, and the multiple inner containers are stacked in the outer container along the height direction.
[0014] Furthermore, the outer container and the inner container are both made of stainless steel, and the heat sink is a stainless steel heat sink.
[0015] The effect of the present invention is that by compacting the oxide in the inner container in layers and providing heat sinks on each layer of oxide, the thermal conductivity can be enhanced, the heat dissipation effect of the oxide can be improved, and the serious pressure increase in the container caused by heat accumulation, thereby avoiding the leakage of radioactive materials, or the self-sintering of oxides in high-temperature areas. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 It is a schematic diagram of the existing plutonium product container;
[0017] Figure 2 It is a schematic diagram of the explosion structure of an actinide oxide temporary storage container of the present invention;
[0018] Figure 3 It is a schematic diagram of the matching relationship between the inner container and the outer container;
[0019] Figure 4 It is a schematic diagram of the positional relationship of multiple inner containers placed in an outer container;
[0020] Description of reference numerals:
[0021] 1. Outer container; 2. Inner container; 3. Heat sink; 11. Outer cover; 21. Inner cover. DETAILED DESCRIPTION
[0022] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.
[0023] like Figure 2-4 As shown, the present invention provides an actinide oxide temporary storage container, comprising an outer container 1 and an inner container 2, wherein the inner container 2 is located inside the outer container 1, and the actinide oxides are layered in the inner container 2 along the height direction, and each layer of the actinide oxides is provided with a heat sink 3, and each layer of the actinide oxides is in a compacted state.
[0024] It can be understood that for mixed oxides with low thermal conductivity, by compacting each layer of oxide and providing heat sinks 3 on each layer of oxide, the thermal conductivity can be enhanced and better heat dissipation of the oxide can be achieved.
[0025] It can be understood that the shape of the heat sink 3 is adapted to the inner container 2 .
[0026] In this embodiment, the compacting pressure of the oxide is not less than 20 MPa, and the heat sink 3 is a stainless steel heat sink.
[0027] In this embodiment, the outer container 1 and the inner container 2 are both made of stainless steel.
[0028] Furthermore, the outer container 1 is fitted with the inner container 2, wherein the thickness of the side wall of the inner container 2 gradually decreases from top to bottom along the height direction, and the thickness of the side wall of the outer container 1 gradually increases from top to bottom along the height direction.
[0029] In this embodiment, the thickness of the side wall of the inner container 2 gradually decreases from top to bottom, forming a "thick at the top and thin at the bottom" cone; while the thickness of the side wall of the outer container 1 gradually increases from top to bottom, forming a cone that can fit tightly with the inner container 2. When the americium-curium mixed oxide is loaded into the inner container 2, it can fit tightly with the outer container 1 by gravity, and the decay heat of the oxide can be directly extracted through the metal, thereby greatly improving the heat extraction efficiency and reducing the temperature of the center area of the oxide.
[0030] In this embodiment, the outer container 1 is similar to the glass solidification product container commonly used in the post-processing plant. The temporary storage container can be directly placed in the vertical shaft of the glass solidification product container temporary storage of the post-processing plant for cooling.
[0031] Furthermore, there is a gap between the outer container 1 and the inner container 2, and the gap is filled with a heat-conducting medium.
[0032] Furthermore, the heat conducting medium is a low melting point metal.
[0033] Furthermore, the gap between the outer container 1 and the inner container 2 is 2.5 mm to 3.5 mm.
[0034] In this embodiment, a low melting point metal such as lead or tin is filled between the inner container 2 and the outer container 1, and the low melting point metal is used as a heat conducting medium between the inner container 2 and the outer container 1. The low melting point metal can be pre-coated on the inner wall of the outer container 1, or can be wound around the outer wall of the inner container 2 in the form of a metal wire after the inner container 2 is filled and sealed.
[0035] Furthermore, the inner container 2 is also filled with an inert gas.
[0036] Furthermore, the outer container 1 is provided with an outer cover 11 for closing or opening the outer container 1 , and the inner container 2 is provided with an inner cover 21 for closing or opening the inner container 2 .
[0037] In this embodiment, the inner container 2 is placed in the outer container 1 and the outer cover is welded. The outer container 1 is heated to the melting point of the low-melting-point metal, and the metals such as lead and tin are melted to fill the gap between the inner and outer containers 2 and the outer container 1. The heating device is removed, and the temperature of the temporary storage container is lowered and the low-melting-point metal is solidified. Since the gap between the outer wall of the inner container 2 and the inner wall of the outer container 1 is very small (2.5mm-3.5mm), the amount of low-melting-point metal filled is not much. If it is necessary to retrieve the americium-curium mixed oxide, it is only necessary to heat the outer container 1, and the inner container 2 can be taken out after the filling metal is melted.
[0038] Furthermore, the bottom of the outer container 1 is in an arc shape that is concave toward the center, and the bottom of the inner container 2 is adapted to the outer container 1 .
[0039] It can be understood that by setting the bottom of the outer container 1 to be an arc shape that is concave toward the center, the stability of multiple temporary storage containers when stacked up and down can be increased, avoiding the situation where the vertical stacking stability is affected by only slight deformation.
[0040] In this embodiment, the arc-shaped depression at the bottom of the outer container 1 can also cooperate with a special gripper to achieve the lifting of the temporary storage container.
[0041] Furthermore, there are multiple inner containers 2, and the multiple inner containers 2 are stacked in the outer container 1 along the height direction.
[0042] The principle of use of the temporary storage container provided by the present invention is as follows: when the oxide needs to be sealed, the oxide is first compacted in layers and placed in the inner container 2, and each layer of the oxide is provided with a heat sink 3, and then the inner container 2 is sealed with the inner cover 21, and the inner container 2 is placed in the outer container 1. At this time, when the inner container 2 is in direct contact with the outer container 1, the outer container 1 is sealed with the outer cover 11, and the temporary storage container is directly placed in the shaft of the temporary storage warehouse of the glass solidification product container of the post-processing plant for cooling. When there is a gap between the inner container 2 and the outer container 1, a heat-conducting medium is first filled into the gap, and then the outer container 1 is sealed with the outer cover 11, and finally the temporary storage container is directly placed in the shaft of the temporary storage warehouse of the glass solidification product container of the post-processing plant for cooling. When the sealed oxide needs to be retrieved, the operation is the opposite of the above process.
[0043] It can be seen from the above embodiments that the present invention can enhance thermal conductivity and improve the heat dissipation effect of the oxide by compacting the oxide in the inner container in layers and providing heat sinks on each layer of oxide, thereby avoiding serious pressure increase in the container caused by heat accumulation, thereby causing leakage of radioactive materials, or self-sintering of oxides in high-temperature areas.
[0044] The device described in the present invention is not limited to the embodiments described in the specific implementation manner. Those skilled in the art may derive other implementation manners based on the technical solution of the present invention, which also fall within the technical innovation scope of the present invention.
Claims
1. A temporary storage container for actinide oxides, characterized in that: include: An outer container and an inner container, wherein the inner container is located inside the outer container, and actinide oxides are arranged in layers in the inner container along the height direction, each layer of actinide oxides is provided with a heat sink, and each layer of actinide oxides is in a compacted state.
2. The actinide oxide temporary storage container according to claim 1, characterized in that: The outer container is fitted with the inner container, wherein the thickness of the side wall of the inner container gradually decreases from top to bottom along the height direction, and the thickness of the side wall of the outer container gradually increases from top to bottom along the height direction.
3. The temporary storage container for actinide oxides according to claim 1, characterized in that: There is a gap between the outer container and the inner container, and the gap is filled with a heat-conducting medium.
4. The temporary storage container for actinide oxides according to claim 3, characterized in that: The heat conducting medium is a low melting point metal.
5. The temporary storage container for actinide oxides according to claim 3, characterized in that: The gap between the outer container and the inner container is 2.5 mm to 3.5 mm.
6. The actinide oxide temporary storage container according to claim 1, characterized in that: The inner container is also filled with an inert gas.
7. The actinide oxide temporary storage container according to claim 1, characterized in that: The outer container is provided with an outer cover for closing or opening the outer container, and the inner container is provided with an inner cover for closing or opening the inner container.
8. The temporary storage container for actinide oxides according to claim 1, characterized in that: The bottom of the outer container is in an arc shape that is concave toward the center, and the bottom of the inner container is adapted to the outer container.
9. The actinide oxide temporary storage container according to claim 1, characterized in that: There are multiple inner containers, and the multiple inner containers are stacked in the outer container along the height direction.
10. The temporary storage container for actinide oxides according to claim 1, characterized in that: The outer container and the inner container are both made of stainless steel, and the heat sink is a stainless steel heat sink.