Composite material and method of manufacture, storage container and method of manufacture, apparatus for manufacture

Abstract

This disclosure relates to the field of functional polymer composite materials technology, specifically to composite materials and their preparation methods, storage containers and their preparation methods, and preparation apparatus. The composite material is composed of epoxy resin, a curing agent, and boron carbide, wherein the mass ratio of the epoxy resin, the curing agent, and the boron carbide is 100:(20~50):(5~35); wherein the epoxy resin is a multifunctional epoxy resin, and the curing agent is a room temperature curing agent; the composite material of this disclosure possesses excellent neutron absorption capacity, significant thermal stability, good corrosion resistance, and feasible engineering implementation performance.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of functional polymer composite materials, in particular, to a composite material and a preparation method, a storage container and a preparation method, and a preparation device. BACKGROUND

[0002] The spent fuel storage container is a key link to ensure the safe operation of nuclear power plants and reprocessing plants, and the inner liner of the shielding material needs to meet multiple stringent requirements under long-term service conditions: excellent neutron absorption capacity, significant thermal stability, good corrosion resistance, and feasible engineering implementation performance. The preparation of the inner liner in the related technology needs to be cured at high temperature, and the engineering implementation performance is low.

[0003] It should be noted that the information disclosed in the above background section is only used to strengthen the understanding of the background of the present disclosure, and therefore can include information that does not constitute prior art known to those of ordinary skill in the art. SUMMARY

[0004] The purpose of the present disclosure is to overcome the shortcomings of the prior art, provide a composite material and a preparation method, a storage container and a preparation method, and a preparation device. The inner liner prepared by using the composite material has excellent neutron absorption capacity, significant thermal stability, good corrosion resistance, and feasible engineering implementation performance.

[0005] According to one aspect of the present disclosure, a composite material for neutron shielding is provided, which is composed of an epoxy resin, a curing agent, and boron carbide, and the mass ratio of the epoxy resin, the curing agent, and the boron carbide is 100: (20-50): (5-35); wherein the epoxy resin is a multifunctional epoxy resin, and the curing agent is a room temperature curing agent.

[0006] In one embodiment of the present disclosure, the epoxy resin includes at least one of a phenol type novolac epoxy resin, a bisphenol A type novolac epoxy resin, an o-cresol novolac epoxy resin, a glycidyl ester type epoxy resin, a glycidyl amine type epoxy resin, and an alicyclic epoxy resin.

[0007] The curing agent includes at least one of an aromatic amine, a phenolic amine, an alicyclic amine, and a polyether amine.

[0008] According to another aspect of the present disclosure, a spent fuel storage container is provided, which includes the above-mentioned composite material for neutron shielding.

[0009] According to another aspect of the present disclosure, a preparation method of the above-mentioned composite material for neutron shielding is provided, which includes:

[0010] taking a predetermined amount of epoxy resin as a matrix, adding a predetermined amount of boron carbide powder to the matrix in batches, stirring the system under a first vacuum degree until the epoxy resin and the boron carbide powder are uniformly mixed to obtain a first mixture;

[0011] adding a predetermined amount of a curing agent to the first mixture, keeping the first vacuum degree unchanged and continuing to stir, and obtaining a second mixture after the system is uniformly mixed;

[0012] adjusting the vacuum environment parameters, increasing the vacuum degree from the first vacuum degree to a second vacuum degree, and stirring the second mixture under the second vacuum degree for a preset time length to complete the defoaming treatment through vacuum stirring, and obtaining the composite material for neutron shielding.

[0013] In an embodiment of the present disclosure, the first vacuum degree is -0.02 Mpa to -0.06 Mpa, the second vacuum degree is -0.07 Mpa to -0.1 Mpa, and the preset time length is 5 min to 30 min.

[0014] In an embodiment of the present disclosure, in the preparation method, a planetary stirrer is used for stirring, the planetary stirrer has a revolution rate of 10 r / min to 50 r / min and a rotation rate of 200 r / min to 1000 r / min.

[0015] According to another aspect of the present disclosure, a preparation method of the spent fuel storage container is provided, including:

[0016] taking a predetermined amount of epoxy resin as a matrix, adding a predetermined amount of boron carbide powder to the matrix in batches, stirring the system under a first vacuum degree until the epoxy resin and the boron carbide powder are uniformly mixed to obtain a first mixture;

[0017] adding a predetermined amount of a curing agent to the first mixture, keeping the first vacuum degree unchanged and continuing to stir, and obtaining a second mixture after the system is uniformly mixed;

[0018] adjusting the vacuum environment parameters, increasing the vacuum degree from the first vacuum degree to a second vacuum degree, and stirring the second mixture under the second vacuum degree for a preset time length to complete the defoaming treatment through vacuum stirring, and obtaining the composite material for neutron shielding.

[0019] pouring the composite material for neutron shielding into a mold for pouring and curing for a preset time to obtain the inner liner of the spent fuel storage container, and obtaining the spent fuel storage container.

[0020] In an embodiment of the present disclosure, the first vacuum degree is -0.02 Mpa to -0.06 Mpa, the second vacuum degree is -0.07 Mpa to -0.1 Mpa, and the preset time length is 5 min to 30 min.

[0021] In the preparation method, the planetary stirrer is used for stirring, the revolution rate of the planetary stirrer is 10 r / min to 50 r / min, and the rotation rate is 200 r / min to 1000 r / min; and the preset time is 0.5 h to 7 d.

[0022] According to another aspect of the present disclosure, a preparation device for the preparation method of the spent fuel storage container is provided, comprising:

[0023] a mixing module having a mixing tank and a planetary stirrer arranged in the mixing tank, the lower end of the mixing tank being provided with a discharge port;

[0024] an epoxy resin supply module in communication with the mixing tank, the epoxy resin supply module being configured to store epoxy resin and deliver a predetermined amount of the epoxy resin into the mixing tank;

[0025] a curing agent supply module in communication with the mixing tank, the curing agent supply module being configured to store a curing agent and deliver a predetermined amount of the curing agent into the mixing tank;

[0026] a boron carbide supply module in communication with the mixing tank, the boron carbide supply module being configured to store boron carbide powder and deliver a predetermined amount of the boron carbide powder into the mixing tank in batches;

[0027] a pouring module arranged at the discharge port of the mixing tank, the pouring module being used for pouring the inner liner of the cured spent fuel storage container;

[0028] a control module electrically connected with the mixing module, the epoxy resin supply module, the curing agent supply module, the boron carbide supply module, and the pouring module, the control module being configured to control the operation of the mixing module, the epoxy resin supply module, the curing agent supply module, the boron carbide supply module, and the pouring module.

[0029] In an embodiment of the present disclosure, the curing agent supply module comprises a first tank body, a first connecting pipe in communication with the first tank body and the mixing tank, and a first metering pump arranged on the first connecting pipe;

[0030] the epoxy resin supply module comprises a second tank body, a second connecting pipe in communication with the second tank body and the mixing tank, and a second metering pump arranged on the second connecting pipe;

[0031] The boron carbide supply module comprises a vacuum lock hopper, a gravity sensor, a first star feeder, a second star feeder, a third tank, a second centrifugal pump and a dust catcher; the lower end of the third tank is communicated with one end of the first star feeder, the other end of the first star feeder is communicated with the vacuum lock hopper, the lower end of the vacuum lock hopper is communicated with the mixing tank through the second star feeder; the gravity sensor is arranged at the lower end of the vacuum lock hopper and used for detecting the weight of the vacuum lock hopper; a third connecting pipe is connected to the upper end of the vacuum lock hopper, and the second centrifugal pump and the dust catcher are arranged on the third connecting pipe, and the dust catcher is located between the second centrifugal pump and the vacuum lock hopper.

[0032] Compared with the prior art, the present disclosure has the following advantages:

[0033] 1、In the present disclosure, the combination of multifunctional epoxy resin and room temperature curing agent enables the composite material to be cured and formed at room temperature (the room temperature condition of the present disclosure refers to 15℃~30℃), and has excellent high temperature resistance, mechanical strength, radiation aging resistance and chemical corrosion resistance. Compared with the process in the prior art which needs to rely on high temperature curing, the method effectively reduces the dependence on large heating equipment, reduces the production energy consumption and equipment investment, and significantly improves the flexibility and applicability of the process.

[0034] 2、The present disclosure utilizes the higher initial viscosity of the multifunctional epoxy resin, and combines with the optimized material ratio, effectively inhibits the settling and aggregation of boron carbide powder in the mixing, conveying and standing process under high filling of multifunctional epoxy resin. Therefore, not only the excellent neutron absorption capacity and neutron shielding capacity of the composite material under high filling conditions are ensured, but also the uniformity and stability of the composite material for neutron shielding within the construction window period are maintained, and the overall viscosity of the composite material is controlled within the range suitable for pouring forming. Compared with the prior art, the process operability and product consistency are significantly improved.

[0035] 3、The present disclosure connects the mixing module, the epoxy resin supply module, the curing agent supply module, the boron carbide supply module and the pouring module together through the control module to build an integrated automatic preparation device, which completely eliminates the problems of dust exposure, material oxidation, human error and poor batch stability caused by step-by-step and open operation in the prior art, greatly improves the product quality reliability and production safety, and is especially suitable for on-site pouring construction of large-scale special-shaped spent fuel storage containers.

[0036] 4. This disclosure adopts a room temperature curing process throughout, which eliminates the need for complex external heating equipment and precise temperature control systems. This not only significantly reduces energy consumption and equipment investment, but also effectively avoids the risk of internal stress cracking that may be caused by high-temperature curing. At the same time, it has the dual advantages of rapid preliminary shaping in the early stage to shorten the construction period and full cross-linking in the later stage to ensure the final performance, making it highly adaptable to engineering projects.

[0037] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0038] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0039] Figure 1 This is a schematic diagram of the structure of a spent fuel storage container preparation apparatus in one embodiment of the present disclosure.

[0040] Figure 2 Differential scanning calorimetry (DSC) curves of the neutron shielding composite material prepared by the second embodiment in one embodiment of this disclosure.

[0041] Figure 3 This invention discloses a cross-sectional scanning electron microscope (SEM) image and elemental distribution map of the liner prepared by the neutron shielding composite material prepared by the second embodiment.

[0042] Figure label:

[0043] 100. Mixing Module; 1. Mixing Tank; 6. Planetary Agitator; 11. First Centrifugal Pump; 13. First Pressure Gauge; 200. Curing Agent Supply Module; 2. First Tank; 21. First Connecting Pipe; 5. First Metering Pump; 300. Epoxy Resin Supply Module; 3. Second Tank; 31. Second Connecting Pipe; 14. Second Metering Pump; 400. Boron Carbide Supply Module; 7. Vacuum Locking Hopper; 8. Gravity Sensor; 10. First Star Feeder; 15. Second Star Feeder; 4. Third Tank; 16. Second Centrifugal Pump; 9. Dust Collector; 12. Casting Module; 17. Control Module. Detailed Implementation

[0044] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore detailed descriptions of them will be omitted. Furthermore, the drawings are merely illustrative of this disclosure and are not necessarily drawn to scale.

[0045] Although relative terms such as "up" and "down" are used in this specification to describe the relative relationship of one component of an icon to another, these terms are used only for convenience, such as according to the orientation of the examples shown in the accompanying drawings. It is understood that if the device of the icon is flipped upside down, the component described as "up" will become the component described as "down." When a structure is "up" of another structure, it may mean that the structure is integrally formed on the other structure, or that the structure is "directly" mounted on the other structure, or that the structure is "indirectly" mounted on the other structure through another structure.

[0046] The terms “a,” “one,” “the,” and “the” are used to indicate the existence of one or more elements / components / etc.; the terms “including” and “having” are used to indicate an open-ended inclusion and to mean that there may be other elements / components / etc. in addition to the listed elements / components / etc.; the terms “first,” “second,” and “third,” etc., are used only as markers and are not a limitation on the number of objects.

[0047] In this disclosure, "system" refers to the whole of all materials involved in the mixing process in the current step.

[0048] Spent fuel storage containers are a critical component in ensuring the safe operation of nuclear power plants and reprocessing facilities. The shielding material lining them must meet multiple stringent requirements simultaneously under long-term service conditions: excellent neutron absorption capacity, significant thermal stability, good corrosion resistance, and feasible engineering implementation performance.

[0049] The preparation of the lining of spent fuel storage containers in related technologies usually requires the use of materials such as flame retardants, curing agents, phenolic epoxy resin matrix and neutron absorbers. The curing process requires high-temperature curing with the help of external heating equipment, such as exceeding 120°C, which is costly, complex and has the risk of internal stress cracking.

[0050] To address at least one of the technical problems, this disclosure provides a composite material for neutron shielding, comprising epoxy resin, a curing agent, and boron carbide, wherein the mass ratio of epoxy resin, curing agent, and boron carbide is 100:(20~50):(5~35), wherein the epoxy resin is a multifunctional epoxy resin, and the curing agent is a room temperature curing agent. It is understood that in this composite material, the multifunctional epoxy resin serves as the matrix material.

[0051] This disclosure describes the preparation of a neutron shielding composite material using a multifunctional epoxy resin, a room-temperature curing agent, and boron carbide powder. This method enables the composite material to cure at room temperature, reducing reliance on large heating equipment, while also providing it with high-temperature resistance, corrosion resistance, and high-neutron shielding capabilities. Furthermore, this disclosure specifies the ratio of epoxy resin, curing agent, and boron carbide as 100:(20~50):(5~35), allowing for synergistic optimization of the epoxy resin, curing agent, and boron carbide. On one hand, this ratio ensures a balance between neutron shielding efficiency, mechanical strength, and curing integrity, preventing sedimentation and delamination due to excessive boron carbide or insufficient shielding due to insufficient boron carbide, while also preventing incomplete curing or excessive brittleness caused by an imbalance in the curing agent ratio. On the other hand, this ratio range balances performance stability and process feasibility, ensuring good batch production consistency and long-term service reliability, thereby meeting the stringent requirements of spent fuel storage containers for nuclear safety and engineering applications.

[0052] Optionally, the epoxy resin includes one or at least two of the following: phenolic epoxy resin, bisphenol A phenolic epoxy resin, o-cresol epoxy resin, glycidyl ester epoxy resin, glycidyl amine epoxy resin, and alicyclic epoxy resin; when multiple types are used, their proportions are set according to requirements. The epoxy resin used in this disclosure contains three or more epoxy groups in its molecular unit structure, enabling it to form a three-dimensional network structure with higher crosslinking density during room temperature curing. This not only improves the high-temperature resistance of the cured product but also maintains excellent mechanical strength and dimensional stability. Simultaneously, the abundant functional groups in the epoxy resin molecule endow it with excellent resistance to radiation aging and chemical corrosion, thereby significantly extending the service life of the material in harsh service environments. Furthermore, the high initial viscosity of the epoxy resin provides a good suspension carrier for high-density, high-content boron carbide powder, effectively mitigating the aggregation of fillers during casting and curing.

[0053] Optionally, the curing agent includes one or at least two of aromatic amines, phenolic amines, alicyclic amines, and polyether amines; when multiple types are used, their proportions are set according to requirements. The curing temperature of the curing agent is between 15℃ and 30℃, a temperature range within which the curing reaction can be completed without additional heating. The curing agents used in this disclosure are all amine-based curing agents because amine groups have higher reactivity, enabling the epoxy resin to fully cure under room temperature conditions, meeting the process requirements for on-site construction of large structures. Furthermore, the molecular structures of these amine curing agents contain stable aromatic rings, rigid segments, or alicyclic structures, giving the cured three-dimensional cross-linked network higher rigidity and thermal stability, significantly improving the long-term heat resistance of the composite material in the application environment of spent fuel storage containers. Simultaneously, the selected curing agent also imparts excellent radiation resistance and chemical corrosion resistance to the cured product, ensuring the long-term reliability of the lining under high temperature and high humidity conditions.

[0054] Based on this composite material, this disclosure also provides a spent fuel storage container made of the composite material, wherein the inner lining of the spent fuel storage container is made of the composite material.

[0055] Based on the above-mentioned composite material, this disclosure provides a method for preparing the composite material, comprising:

[0056] A predetermined amount of epoxy resin is used as the matrix, and a predetermined amount of boron carbide powder is added to it in batches; under a first vacuum condition, the system is stirred using a planetary stirrer until the epoxy resin and boron carbide powder are mixed evenly to obtain a first mixture;

[0057] Add a predetermined amount of curing agent to the first mixture, maintain the first vacuum level and continue stirring. After the system is mixed evenly, the second mixture is obtained.

[0058] Adjust the vacuum environment parameters to increase the vacuum level from the first vacuum level to the second vacuum level, and stir the second mixture for a preset time under the second vacuum level. Complete the degassing treatment through vacuum stirring to obtain a composite material for neutron shielding.

[0059] In this preparation method, the planetary stirrer's revolution speed is limited to 10 r / min to 50 r / min, and its rotation speed is limited to 200 r / min to 1000 r / min. This revolution speed ensures sufficient overall circulation of the material within the mixing tank 1, effectively eliminating mixing dead zones and preventing the deposition of high-density boron carbide powder on the bottom and walls of the mixing tank 1. This rotation speed applies strong shear force to the agglomerated boron carbide powder, achieving efficient breakage and dispersion in the high-viscosity epoxy resin, thereby achieving nanoscale uniform mixing while avoiding excessive air entrainment due to excessively high rotation speed. Furthermore, in this preparation method, the first vacuum degree is limited to -0.02 MPa to -0.06 MPa. At this first vacuum degree, dissolved air and air bubbles entrained during the stirring process can be effectively eliminated from the subsequent mixture system, while avoiding excessive volatilization of low-boiling-point components in the epoxy resin system due to excessively high vacuum. This maintains the stability of the material ratio while ensuring mixing uniformity, laying the foundation for the subsequent high-vacuum deep degassing stage.

[0060] In this preparation method, the second vacuum level is set to -0.07 MPa to -0.1 MPa, and the preset time is 5 min to 30 min. Under this high vacuum condition, the internal pressure of bubbles in the mixture system can be significantly reduced, causing them to expand rapidly and migrate to the free surface to rupture, thereby efficiently removing micron- and submicron-sized bubbles that are difficult to remove by conventional degassing methods. This vacuum environment can also effectively extract trace amounts of water vapor that may be generated in the subsequent curing process, preventing them from forming defects inside the prepared liner. At the same time, the appropriate stirring time can continuously renew the material surface under vacuum conditions, breaking down the surface tension barrier of bubbles and promoting the escape of deep bubbles. This time range ensures thorough degassing while avoiding the risk of premature prepolymerization due to excessive mechanical energy input causing the temperature of the mixture system to rise.

[0061] The preparation method proposed in this disclosure effectively solves the problems of easy sedimentation, uneven mixing, and difficulty in removing bubbles in the preparation of boron carbide powder under high filling conditions, as well as the low efficiency and poor safety of existing stepwise processes.

[0062] In one embodiment of this disclosure, a method for preparing a spent fuel storage container is also provided, comprising:

[0063] A predetermined amount of epoxy resin is used as the matrix, and a predetermined amount of boron carbide powder is added to it in batches; under a first vacuum condition, the system is stirred until the epoxy resin and the boron carbide powder are mixed evenly to obtain a first mixture;

[0064] Add a predetermined amount of curing agent to the first mixture, maintain the first vacuum level and continue stirring. After the system is mixed evenly, a second mixture is obtained.

[0065] Adjust the vacuum environment parameters to increase the vacuum level from the first vacuum level to the second vacuum level, and stir the second mixture for a preset time under the second vacuum level. Complete the degassing treatment through vacuum stirring to obtain a composite material for neutron shielding.

[0066] The neutron shielding composite material is poured into a mold for casting and curing for a preset time to obtain the liner of the spent fuel storage container and thus the spent fuel storage container.

[0067] In this disclosure, the curing preset time is limited to 0.5 h to 7 days. This range of curing preset time can simultaneously take into account the preparation efficiency and the final performance of the liner. A shorter curing preset time can meet the needs of rapid preliminary shaping and mold movement, which is beneficial for continuous operation and shortens the production cycle; while a longer curing preset time allows the system to undergo more complete cross-linking at room temperature, thereby making the cross-linked network structure of the product (i.e., the liner) more perfect, and ultimately achieving better performance in terms of heat resistance, mechanical strength, radiation resistance and corrosion resistance.

[0068] Based on the above method, this disclosure provides the following embodiments to explain the preparation method of the above-mentioned spent fuel storage container:

[0069] This disclosure provides a first embodiment:

[0070] Step 1: 2 kg of AG-80 glycidylamine epoxy resin is delivered from the second tank 3 to the mixing tank 1 through the second metering pump 14. The mixing tank 1 is evacuated to a vacuum degree of -0.02 MPa. The planetary stirrer 6 is then turned on.

[0071] Step 2: Using the vacuum lock hopper 7 and the second star-shaped feeder 15, 0.1 kg of boron carbide powder, weighed by the gravity sensor 8, is automatically added in batches to the mixing tank 1. The planetary stirrer 6 is controlled to rotate at a speed of 15 r / min and a rotational speed of 400 r / min to stir the system (which includes boron carbide powder and AG-80 glycidylamine epoxy resin) until the boron carbide powder and AG-80 glycidylamine epoxy resin are evenly mixed to obtain the first mixture. Of course, the rotational speed and rotational speed of the planetary stirrer 6 can also be set in step 1.

[0072] Step 3: 0.7 kg of isophorone diamine cycloamine curing agent is delivered from the second tank 3 to the mixing tank 1 through the first metering pump 5, and the planetary stirrer 6 is controlled to continue stirring while maintaining the first vacuum degree. After the system (which includes isophorone diamine cycloamine curing agent and the first mixture) is mixed evenly, the second mixture is obtained.

[0073] Step 4: Continue to evacuate the mixing tank 1, adjust the vacuum environment parameters in the mixing tank 1 to raise the vacuum degree in the mixing tank 1 to -0.07 MPa, continue to stir the second mixture for 8 minutes, and perform vacuum stirring and degassing treatment to obtain the composite material for neutron shielding.

[0074] Step 5: After vacuum stirring and degassing, the obtained neutron shielding composite material is directly poured into the mold (i.e. casting module) through the discharge valve at the bottom of the mixing tank 1. After curing at room temperature for 4 hours, the inner lining of the spent fuel storage container can be obtained, thus obtaining the spent fuel storage container.

[0075] In this disclosure, various parameters of the lining of the obtained spent fuel storage container were measured. Specifically, the glass transition temperature (Tg) of the lining of the spent fuel storage container prepared according to this embodiment was 159.5°C by DSC measurement; its tensile strength was 39.4 MPa, its elongation at break was 2.4%, and its flexural strength was 94.2 MPa by mechanical property measurement; and its thermal neutron shielding efficiency of a 2 cm thick sample was 98.3%.

[0076] This disclosure provides a second embodiment:

[0077] Step 1: 2 kg of DNE-425 phenolic epoxy resin is delivered from the second tank 3 to the mixing tank 1 through the second metering pump 14. The mixing tank 1 is evacuated to a vacuum degree of -0.03 MPa. The planetary stirrer 6 is then turned on.

[0078] Step 2: Using the vacuum lock hopper 7 and the second star-shaped feeder 15, 0.5 kg of boron carbide powder, weighed by the gravity sensor 8, is automatically added in batches to the mixing tank 1. The planetary stirrer 6 is controlled to rotate at a speed of 25 r / min and a rotational speed of 600 r / min to stir the system (which includes boron carbide powder and DNE-425 phenolic epoxy resin) until the boron carbide powder and DNE-425 phenolic epoxy resin are evenly mixed to obtain the first mixture. Of course, the rotational speed and rotational speed of the planetary stirrer 6 can also be set in step 1.

[0079] Step 3: 0.6 kg of D230 polyetheramine curing agent is delivered from the second tank 3 to the mixing tank 1 through the first metering pump 5, and while maintaining the first vacuum degree, the planetary stirrer 6 is controlled to continue stirring. After the system (which includes D230 polyetheramine curing agent and the first mixture) is mixed evenly, the second mixture is obtained.

[0080] Step 4: Continue to evacuate the mixing tank 1, adjust the vacuum environment parameters in the mixing tank 1 to raise the vacuum degree in the mixing tank 1 to -0.08 MPa, and continue to stir the second mixture for 15 min to perform vacuum stirring and degassing treatment to obtain the composite material for neutron shielding.

[0081] Step 5: After vacuum stirring and degassing, the obtained neutron shielding composite material is directly poured into the casting module 12 through the discharge valve at the bottom of the mixing tank 1. After curing at room temperature for 3 days, the inner lining of the spent fuel storage container is obtained, and thus the spent fuel storage container is obtained.

[0082] In this disclosure, various parameters of the lining of the obtained spent fuel storage container were measured. Specifically, the glass transition temperature (Tg) of the lining of the spent fuel storage container prepared according to this embodiment was determined by DSC to be 164.4 °C (see [link to DSC]). Figure 2 (Where, the horizontal axis represents temperature and the vertical axis represents heat flow rate), from Figure 2 It can be seen from the data that the glass transition temperature (Tg) of the lining of the spent fuel storage container is 164.4°C. The mechanical properties show that its tensile strength is 47.8 MPa, elongation at break is 2.4%, and bending strength is 122.2 MPa. At the same time, the thermal neutron shielding efficiency of the 2 cm thick sample was measured to be 99.3%.

[0083] See Figure 3 ,from Figure 3 It can be seen from the fact that the liner is made of composite material for neutron shielding ( Figure 3 (The gray attached image on the left) shows no obvious boron carbide aggregation, and the signal intensity distribution pattern of boron is highly consistent with that of the expected uniformly distributed elements (carbon, oxygen, and nitrogen), exhibiting a similar, overall uniform brightness distribution. No enriched bright spots or depleted dark areas unique to boron and unrelated to the distribution patterns of other elements were observed.

[0084] This disclosure provides a third embodiment:

[0085] Step 1: 2 kg of F51 phenolic epoxy resin is delivered from the second tank 3 to the mixing tank 1 through the second metering pump 14. The mixing tank 1 is evacuated to a vacuum degree of -0.06 MPa. The planetary stirrer 6 is then turned on.

[0086] Step 2: Using the vacuum lock hopper 7 and the second star-shaped feeder 15, 0.2 kg of boron carbide powder, weighed by the gravity sensor 8, is automatically added in batches to the mixing tank 1. The planetary stirrer 6 is controlled to rotate at a speed of 50 r / min and a rotational speed of 1000 r / min to stir the system (which includes boron carbide powder and F51 phenolic epoxy resin) until the boron carbide powder and F51 phenolic epoxy resin are evenly mixed to obtain the first mixture. Of course, the rotational speed and rotational speed of the planetary stirrer 6 can also be set in step 1.

[0087] Step 3: 0.5 kg of VT-5236 aromatic amine curing agent is delivered from the second tank 3 to the mixing tank 1 through the first metering pump 5. While maintaining the first vacuum level, the planetary stirrer 6 is controlled to continue stirring. After the system (which includes VT-5236 aromatic amine curing agent and the first mixture) is mixed evenly, the second mixture is obtained.

[0088] Step 4: Continue to evacuate the mixing tank 1, adjust the vacuum environment parameters in the mixing tank 1 to raise the vacuum level in the mixing tank 1 to -0.1 MPa, and continue to stir the second mixture for 30 minutes to perform vacuum stirring and degassing treatment to obtain the composite material for neutron shielding.

[0089] Step 5: After vacuum stirring and degassing, the obtained neutron shielding composite material is directly poured into the casting module 12 through the discharge valve at the bottom of the mixing tank 1. After curing at room temperature for 1 day, the inner lining of the spent fuel storage container can be obtained, thus obtaining the spent fuel storage container.

[0090] In this disclosure, various parameters of the lining of the obtained spent fuel storage container were measured. Specifically, the glass transition temperature (Tg) of the lining of the spent fuel storage container prepared according to this embodiment was 154.4 °C by DSC measurement; the tensile strength was 32.1 MPa, the elongation at break was 1.9%, and the bending strength was 92.8 MPa by mechanical property measurement; at the same time, the thermal neutron shielding efficiency of the 2 cm thick sample was measured to be 98.9%.

[0091] This disclosure provides a fourth embodiment:

[0092] Step 1: 2 kg of TDE-85 glycidyl ester epoxy resin is delivered from the second tank 3 to the mixing tank 1 through the second metering pump 14. The mixing tank 1 is evacuated to a vacuum degree of -0.04 MPa. The planetary stirrer 6 is then turned on.

[0093] Step 2: Using the vacuum lock hopper 7 and the second star-shaped feeder 15, 0.7 kg of boron carbide powder, weighed by the gravity sensor 8, is automatically added in batches to the mixing tank 1. The planetary stirrer 6 is controlled to rotate at a speed of 40 r / min and a rotational speed of 800 r / min to stir the system (which includes boron carbide powder and TDE-85 glycidyl ester epoxy resin) until the boron carbide powder and TDE-85 glycidyl ester epoxy resin are evenly mixed to obtain the first mixture. Of course, the rotational speed and rotational speed of the planetary stirrer 6 can also be set in step 1.

[0094] Step 3: 0.8 kg of T31 phenolic amine curing agent is delivered from the second tank 3 to the mixing tank 1 through the first metering pump 5, and the planetary stirrer 6 is controlled to continue stirring while maintaining the first vacuum degree. After the system (which includes T31 phenolic amine curing agent and the first mixture) is mixed evenly, the second mixture is obtained.

[0095] Step 4: Continue to evacuate the mixing tank 1, adjust the vacuum environment parameters in the mixing tank 1 to raise the vacuum degree in the mixing tank 1 to -0.09 MPa, and continue to stir the second mixture for 5 minutes to perform vacuum stirring and degassing treatment to obtain the composite material for neutron shielding.

[0096] Step 5: After vacuum mixing and degassing, the resulting mixture is poured directly into the casting module 12 through the discharge valve at the bottom of the mixing tank 1. After curing at room temperature for 0.5 hours, the inner lining of the spent fuel storage container is obtained, thus obtaining the spent fuel storage container.

[0097] In this disclosure, various parameters of the lining of the spent fuel storage container were measured. Specifically, the glass transition temperature (Tg) of the lining of the spent fuel storage container prepared according to this embodiment was 159.0 °C by DSC measurement; the tensile strength was 43.7 MPa, the elongation at break was 1.1%, and the flexural strength was 115.6 MPa by mechanical property measurement; at the same time, the thermal neutron shielding efficiency of the 2 cm thick sample was measured to be 99.8%.

[0098] This disclosure provides a fifth embodiment:

[0099] Step 1: 2 kg of Syna-Epoxy 28 alicyclic epoxy resin is delivered from the second tank 3 to the mixing tank 1 through the second metering pump 14. The mixing tank 1 is evacuated to a vacuum degree of -0.05 MPa. The planetary stirrer 6 is then turned on.

[0100] Step 2: Using the vacuum lock hopper 7 and the second star-shaped feeder 15, 0.4 kg of boron carbide powder, weighed by the gravity sensor 8, is automatically added in batches to the mixing tank 1. The planetary stirrer 6 is controlled to rotate at a speed of 30 r / min and a rotational speed of 700 r / min to stir the system (which includes boron carbide powder and Syna-Epoxy 28 alicyclic epoxy resin) until the boron carbide powder and Syna-Epoxy 28 alicyclic epoxy resin are evenly mixed to obtain the first mixture. Of course, the rotational speed and rotational speed of the planetary stirrer 6 can also be set in step 1.

[0101] Step 3: 0.6 kg of HS-590 aromatic amine curing agent is delivered from the second tank 3 to the mixing tank 1 through the first metering pump 5. While maintaining the first vacuum level, the planetary stirrer 6 is controlled to continue stirring. After the system (which includes HS-590 aromatic amine curing agent and the first mixture) is mixed evenly, the second mixture is obtained.

[0102] Step 4: Continue to evacuate the mixing tank 1, adjust the vacuum environment parameters in the mixing tank 1 to raise the vacuum degree in the mixing tank 1 to -0.09 MPa, and continue to stir the second mixture for 20 minutes to perform vacuum stirring and degassing treatment to obtain the composite material for neutron shielding.

[0103] Step 5: After vacuum mixing and degassing, the resulting mixture is poured directly into the casting module 12 through the discharge valve at the bottom of the mixing tank 1. After curing at room temperature for 7 days, the inner lining of the spent fuel storage container is obtained, thus obtaining the spent fuel storage container.

[0104] This disclosure measures various parameters of the lining of the obtained spent fuel storage container. Specifically, the glass transition temperature (Tg) of the lining of the spent fuel storage container prepared according to this embodiment is 173.1 °C by DSC measurement; the tensile strength is 50.2 MPa, the elongation at break is 1.8%, and the bending strength is 126.6 MPa by mechanical property measurement; at the same time, the thermal neutron shielding efficiency of the 2 cm thick sample is measured to be 99.0%.

[0105] This disclosure provides a sixth embodiment:

[0106] Step 1: 2 kg of NPCN-704 o-cresol epoxy resin is delivered from the second tank 3 to the mixing tank 1 through the second metering pump 14. The mixing tank 1 is evacuated to a vacuum degree of -0.03 MPa. The planetary stirrer 6 is then turned on.

[0107] Step 2: Using the vacuum lock hopper 7 and the second star-shaped feeder 15, 0.3 kg of boron carbide powder, weighed by the gravity sensor 8, is automatically added in batches to the mixing tank 1. The planetary stirrer 6 is controlled to rotate at a speed of 20 r / min and a rotational speed of 600 r / min to stir the system (which includes boron carbide powder and NPCN-704 o-cresol epoxy resin) until the boron carbide powder and NPCN-704 o-cresol epoxy resin are evenly mixed to obtain the first mixture. Of course, the planetary stirrer 6's rotational speed and rotational speed can also be set in step 1.

[0108] Step 3: 0.4 kg of isophorone diamine cycloamine curing agent is delivered from the second tank 3 to the mixing tank 1 through the first metering pump 5, and while maintaining the first vacuum degree, the planetary stirrer 6 is controlled to continue stirring. After the system (which includes isophorone diamine cycloamine curing agent and the first mixture) is mixed evenly, the second mixture is obtained.

[0109] Step 4: Continue to evacuate the mixing tank 1, adjust the vacuum environment parameters in the mixing tank 1 to raise the vacuum degree in the mixing tank 1 to -0.08 MPa, and continue to stir the second mixture for 15 minutes to perform vacuum stirring and degassing treatment to obtain the composite material for neutron shielding.

[0110] Step 5: After vacuum mixing and degassing, the resulting mixture is poured directly into the casting module 12 through the discharge valve at the bottom of the mixing tank 1. After curing at room temperature for 8 hours, the inner lining of the spent fuel storage container is obtained, thus obtaining the spent fuel storage container.

[0111] This disclosure measures various parameters of the lining of the obtained spent fuel storage container. Specifically, the glass transition temperature (Tg) of the lining of the spent fuel storage container prepared according to this embodiment is 162.3 °C by DSC measurement; the tensile strength is 45.2 MPa, the elongation at break is 1.8%, and the flexural strength is 118.6 MPa by mechanical property measurement; at the same time, the thermal neutron shielding efficiency of the 2 cm thick sample is measured to be 98.6%.

[0112] This disclosure provides a seventh embodiment:

[0113] Step 1: 2 kg of TDE-85 glycidyl ester epoxy resin is delivered from the second tank 3 to the mixing tank 1 through the second metering pump 14. The mixing tank 1 is evacuated to a vacuum degree of -0.02 MPa. The planetary stirrer 6 is then turned on.

[0114] Step 2: Using the vacuum lock hopper 7 and the second star-shaped feeder 15, 0.3 kg of boron carbide powder, weighed by the gravity sensor 8, is automatically added in batches to the mixing tank 1. The planetary stirrer 6 is controlled to rotate at a speed of 10 r / min and a rotational speed of 200 r / min to stir the system (which includes boron carbide powder and TDE-85 glycidyl ester epoxy resin) until the boron carbide powder and TDE-85 glycidyl ester epoxy resin are evenly mixed to obtain the first mixture. Of course, the rotational speed and rotational speed of the planetary stirrer 6 can also be set in step 1.

[0115] Step 3: 1.0 kg of D230 polyetheramine curing agent is delivered from the second tank 3 to the mixing tank 1 through the first metering pump 5, and the planetary stirrer 6 is controlled to continue stirring while maintaining the first vacuum degree. After the system (which includes D230 polyetheramine curing agent and the first mixture) is mixed evenly, the second mixture is obtained.

[0116] Step 4: Continue to evacuate the mixing tank 1, adjust the vacuum environment parameters in the mixing tank 1 to raise the vacuum degree in the mixing tank 1 to -0.08 MPa, and continue to stir the second mixture for 10 minutes to perform vacuum stirring and degassing treatment to obtain the composite material for neutron shielding.

[0117] Step 5: After vacuum mixing and degassing, the resulting mixture is poured directly into the casting module 12 through the discharge valve at the bottom of the mixing tank 1. After curing at room temperature for 5 days, the inner lining of the spent fuel storage container is obtained, thus obtaining the spent fuel storage container.

[0118] This disclosure measures various parameters of the lining of the obtained spent fuel storage container. Specifically, the glass transition temperature (Tg) of the lining of the spent fuel storage container prepared according to this embodiment is 151.3 °C by DSC measurement; the tensile strength is 31.1 MPa, the elongation at break is 2.3%, and the bending strength is 90.6 MPa by mechanical property measurement; at the same time, the thermal neutron shielding efficiency of the 2 cm thick sample is measured to be 98.7%.

[0119] Table 1 shows the test parameters for the liners prepared using the various embodiments described above. (See Table 1 for details.)

[0120] Table 1: Detection parameters of the liners prepared in each embodiment

[0121]

[0122] As can be seen from Table 1, the glass transition temperatures of the linings of the spent fuel storage containers prepared in the embodiments of this disclosure are all greater than 150 °C, indicating that the composite material has excellent thermal stability. The cured network structure can still maintain its integrity at high temperatures, which can meet the performance requirements of the spent fuel storage container under long-term temperature rise environment. The tensile strength of the linings is all above 30 MPa and the flexural strength is all above 90 MPa, indicating that the cured composite material has excellent mechanical strength and deformation resistance, which is sufficient to withstand various static and dynamic mechanical loads during long-term service, ensuring the integrity and reliability of the structure. At the same time, the thermal neutron shielding rate of all linings in the embodiments exceeds 98%, indicating that the composite material has efficient and reliable neutron absorption capacity.

[0123] Based on the above-described method for preparing spent fuel storage containers, this disclosure also provides a preparation apparatus for this method, see [link to apparatus]. Figure 1 It includes a mixing module 100, an epoxy resin supply module 300, a curing agent supply module 200, a boron carbide supply module 400, a casting module 12, and a control module.

[0124] The epoxy resin supply module 300, curing agent supply module 200, and boron carbide supply module 400 are all connected to the mixing module 100. The epoxy resin supply module 300 is configured to store epoxy resin and supply a predetermined amount of epoxy resin to the mixing module 100. The curing agent supply module 200 is configured to store curing agent and supply a predetermined amount of curing agent to the mixing module 100. The boron carbide supply module 400 is configured to store boron carbide powder and supply a predetermined amount of boron carbide powder to the mixing module 100 in batches. The mixing module 100 is configured to receive epoxy resin, curing agent, and boron carbide powder in sequence and stir them evenly to form a composite material for neutron shielding.

[0125] Optionally, the mixing module 100 is also configured to deliver the composite material to the casting module 12, which is configured to cast and cure the composite material to form the liner of the spent fuel storage container.

[0126] Optionally, the control module 17 is electrically connected to the mixing module 100, the epoxy resin supply module 300, the curing agent supply module 200, the boron carbide supply module 400, and the casting module 12. The control module 17 is configured to control the operation of the mixing module 100, the epoxy resin supply module 300, the curing agent supply module 200, the boron carbide supply module 400, and the casting module 12. In this way, the entire preparation device can be automated, eliminating the need for manual labor, thereby increasing efficiency and reducing costs.

[0127] In one embodiment of this disclosure, see [link to relevant documentation]. Figure 1The mixing module 100 includes a mixing tank 1 and a planetary mixer 6. The planetary mixer 6 is installed inside the mixing tank 1. The mixing tank 1 has a discharge port at its lower end and a discharge valve is installed at the discharge port. The casting module 12 is installed at the discharge port and is used to directly cast and cure the composite material (a mixture of uniformly mixed epoxy resin, curing agent and boron carbide powder) discharged from the discharge port to form the lining of the spent fuel storage container.

[0128] In one embodiment of this disclosure, a fifth connecting pipe is connected to the upper end of the mixing tank 1, and a first centrifugal pump 11 is provided on the fifth connecting pipe. The first centrifugal pump 11 is used to evacuate the mixing tank 1.

[0129] In one embodiment of this disclosure, a first pressure gauge 13 is connected to the upper end of the mixing tank 1, which can monitor the pressure inside the mixing tank 1.

[0130] In one embodiment of this disclosure, the curing agent supply module 200 includes a first tank 2 for storing curing agent. The first tank 2 is connected to the mixing tank 1 via a first connecting pipe 21, and a first metering pump 5 is installed on the first connecting pipe 21. In this disclosure, the use of the first metering pump 5 allows for precise control of the curing agent's metering, improving the accuracy of the mixing ratio, and thus ensuring the performance of the composite material used for neutron shielding.

[0131] In one embodiment of this disclosure, the epoxy resin supply module 300 includes a second tank 3 for storing epoxy resin. The second tank 3 is connected to the mixing tank 1 via a second connecting pipe 31, and a second metering pump 14 is provided on the second connecting pipe 31. In this disclosure, the use of the second metering pump 14 can precisely control the metering of epoxy resin, improve the accuracy of the mixing ratio, and thus ensure the performance of the composite material for neutron shielding.

[0132] In one embodiment of this disclosure, the boron carbide supply module 400 includes a vacuum lock hopper 7, a gravity sensor 8, a first star-shaped feeder 10, a second star-shaped feeder 15, a third tank 4, a second centrifugal pump 16, and a dust collector 9. The third tank 4 stores boron carbide powder. The lower end of the third tank 4 is connected to one end of the first star-shaped feeder 10, and the other end of the first star-shaped feeder 10 is connected to the vacuum lock hopper 7. The lower end of the vacuum lock hopper 7 is connected to the mixing tank 1 via the second star-shaped feeder 15. The gravity sensor 8 is located at the lower end of the vacuum lock hopper 7 and is used to detect the weight of the vacuum lock hopper 7, thereby obtaining the weight of the boron carbide powder entering the vacuum lock hopper 7, thus achieving quantitative addition of boron carbide powder. A fourth connecting pipe is connected to the upper end of the vacuum lock hopper 7. The second centrifugal pump 16 and the dust collector 9 are installed on the fourth connecting pipe, with the dust collector 9 located between the second centrifugal pump 16 and the vacuum lock hopper 7. In this disclosure, the second centrifugal pump 16 is used to evacuate the vacuum lock hopper 7, and together with the gravity sensor 8, it enables precise measurement of the weight of boron carbide powder, improves the accuracy of the mixing ratio, and thus ensures the performance of the composite material for neutron shielding.

[0133] In this disclosed example, a second pressure gauge is provided on the vacuum lock 7, which is used to monitor the pressure inside the vacuum lock 7.

[0134] In one embodiment of this disclosure, the control module 17 is electrically connected to the planetary stirrer 6, the first centrifugal pump 11, and the first pressure gauge 13 of the mixing module 100. The control module 17 is also electrically connected to the second metering pump 14 of the epoxy resin supply module 300. Furthermore, the control module 17 is electrically connected to the first metering pump 5 of the curing agent supply module 200. Finally, the control module 17 is electrically connected to the dust collector 9, the first centrifugal pump 11, the gravity sensor 8, the vacuum hopper 7, the first star feeder 10, and the second star feeder 15 of the boron carbide supply module 400.

[0135] In one embodiment of this disclosure, the casting module 12 can be a mold.

[0136] The apparatus proposed in this disclosure realizes an integrated operation of the entire process from raw material metering, high-speed dispersion and mixing, vacuum degassing to final casting and curing, and can be widely used in the field of neutron shielding materials for spent fuel storage tanks.

[0137] The preparation apparatus proposed in this disclosure, through the integration and linkage of various modules, achieves a fully enclosed and automated operation from precise raw material metering, high-speed and efficient dispersion, vacuum dynamic degassing to final automatic casting and curing. This not only simplifies the process steps and reduces uncertainties caused by manual operation, but also fundamentally improves the uniformity and reliability of material preparation. It solves the problems of dust exposure, material oxidation, large human error, and low batch stability in existing high-filling systems preparation processes, significantly improving the consistency and reliability of shielding material performance. Furthermore, it enables high-filling systems to achieve a balance of efficiency, stability, and safety while ensuring shielding performance, providing necessary technical support for the large-scale application of neutron shielding materials for spent fuel storage.

[0138] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the appended claims.

Claims

1. A composite material for neutron shielding, characterized in that, The composite material is composed of epoxy resin, curing agent and boron carbide, wherein the mass ratio of epoxy resin, curing agent and boron carbide is 100:(20~50):(5~35); wherein the epoxy resin is a multifunctional epoxy resin and the curing agent is a room temperature curing agent, which is used to cure the composite material at 15℃~30℃. The epoxy resin is Syna-Epoxy 28 alicyclic epoxy resin, and the curing agent is HS-590 aromatic amine curing agent.

2. A spent fuel storage container, characterized in that, Includes the composite material for neutron shielding as described in claim 1.

3. A method for preparing the composite material for neutron shielding as described in claim 1, characterized in that, include: A predetermined amount of Syna-Epoxy 28 alicyclic epoxy resin was used as the matrix, and a predetermined amount of boron carbide powder was added to it in batches. Under a first vacuum condition, the system was stirred using a planetary stirrer until the epoxy resin and the boron carbide powder were mixed evenly to obtain a first mixture. The planetary stirrer had a common rotational speed of 10 r / min to 50 r / min and a self-rotational speed of 200 r / min to 1000 r / min. The first vacuum degree was -0.02 MPa to -0.06 MPa. Add a predetermined amount of HS-590 aromatic amine curing agent to the first mixture, keep the first vacuum unchanged and continue stirring. After the system is mixed evenly, a second mixture is obtained. Adjust the vacuum environment parameters to increase the vacuum level from the first vacuum level to the second vacuum level, and stir the second mixture for a preset time under the second vacuum level. Complete the degassing treatment through vacuum stirring to obtain a composite material for neutron shielding. The second vacuum level is -0.07Mpa to -0.1Mpa.

4. The method for preparing the composite material for neutron shielding according to claim 3, characterized in that, The preset duration is 5 min to 30 min.

5. A method for preparing the spent fuel storage container according to claim 2, characterized in that, include: A predetermined amount of Syna-Epoxy 28 alicyclic epoxy resin was used as the matrix, and a predetermined amount of boron carbide powder was added to it in batches. Under a first vacuum condition, the system was stirred using a planetary stirrer until the epoxy resin and the boron carbide powder were mixed evenly to obtain a first mixture. The planetary stirrer had a common rotational speed of 10 r / min to 50 r / min and a self-rotational speed of 200 r / min to 1000 r / min. The first vacuum degree was -0.02 MPa to -0.06 MPa. Add a predetermined amount of HS-590 aromatic amine curing agent to the first mixture, keep the first vacuum unchanged and continue stirring. After the system is mixed evenly, a second mixture is obtained. Adjust the vacuum environment parameters to increase the vacuum level from the first vacuum level to the second vacuum level, and stir the second mixture for a preset time under the second vacuum level. Complete the degassing treatment through vacuum stirring to obtain a composite material for neutron shielding. The second vacuum level is -0.07 MPa to -0.1 MPa. The neutron shielding composite material is poured into a mold for casting and curing for a preset time to obtain the liner of the spent fuel storage container and thus the spent fuel storage container.

6. The method for preparing a spent fuel storage container according to claim 5, characterized in that, The preset duration is 5 min to 30 min; the preset time is 0.5 h to 7 d.

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