A system and method for staged fuel loading of a high-temperature gas-cooled reactor

Abstract

The present invention discloses a system and method for staged refueling of a high-temperature gas-cooled reactor. The outlet of the graphite ball storage tank is connected to one end of the graphite ball charging pipe valve at the top of the reactor core and one end of the graphite ball charging pipe valve in the middle of the reactor core. The other end of the graphite ball charging pipe valve at the top of the reactor core is communicated with the top inlet of the high-temperature reactor core chamber, and the other end of the graphite ball charging pipe valve in the middle of the reactor core is communicated with the side inlet of the high-temperature reactor core chamber. A graphite ball position detector is arranged on the inner wall of the high-temperature reactor core chamber. The output end of the graphite ball position detector is connected to the input end of the control system, and the output end of the control system is connected to the control ends of the graphite ball charging pipe valve at the top of the reactor core and the graphite ball charging pipe valve in the middle of the reactor core. This system and method can reduce the impact generated by the falling of graphite balls.

Description

Technical Field

[0001] The present invention belongs to the technical field of refueling technology for high-temperature gas-cooled reactors, and relates to a system and method for staged refueling of high-temperature gas-cooled reactors. Background Art

[0002] The new fuel supply system of a high-temperature gas-cooled reactor undertakes the storage of new fuel elements in a nuclear power plant and supplies them to the reactor core through a fuel handling system, while performing the function of managing new fuel elements. The new fuel feeding subsystem is a subsystem of the new fuel supply system, which performs the refueling function and is composed of a refueling device and a ball flow pipeline. The main equipment includes a new fuel charging tank rack, a single-rail hoist for the tank cover, a refueling platform, a ventilation refueling box, a quick isolation device for the ball path, a counter, and power and instrument control cabinets supporting the system equipment and the counter. The main body of the new fuel feeding subsystem is located in the new fuel refueling room, and part of the ball flow pipeline is located in the buffer pipeline room for loading and unloading.

[0003] When refueling with new fuel, first open the door of the ventilation refueling box, switch the ventilation of the new fuel refueling room compartment to the refueling state, and switch the helium mass spectrometer leak detector to the refueling operation state. After performing an appearance integrity inspection, opening the bag, secondary inspection, and manual counting on the inner platform of the ventilation refueling box, load a specified quantity of components into the specified refueling pipeline according to the master control instruction, and check that the counting results of the upstream and downstream counters of this pipeline are consistent.

[0004] Existing refueling schemes for large commercial high-temperature reactors have the following problems:

[0005] Large commercial high-temperature gas-cooled reactors are different from experimental high-temperature gas-cooled reactors. Since the power of large commercial high-temperature gas-cooled reactors is much greater than that of experimental high-temperature reactors, and the core height of large commercial high-temperature reactors is much greater than that of experimental high-temperature reactors, when the initial fuel falls from the top of the reactor core to the bottom, the speed is faster, and the impact on the fuel balls and the contact surface of the fall (the bottom graphite reflector) is greater. Therefore, in large commercial high-temperature gas-cooled reactors, the frequency of fuel broken balls (graphite balls) is much higher than that in experimental high-temperature reactors. The existing initial refueling schemes have the following defects:

[0006] 1. The in-core components will receive a large impact: When refueling initially, the fuel balls fall from a high place, which will cause a large impact on the bottom graphite reflector of the reactor core; after the fuel balls are broken, the fragments with greater flying kinetic energy will impact the side graphite reflector and the bottom graphite reflector, which may cause defects, deformation or even detachment of some graphite bricks.

[0007] 2. Radioactive leakage caused by broken balls: When the fuel balls are broken, the fuel particles encapsulated inside the graphite balls and dispersed inside the graphite body will be exposed, and the radioactivity will flow into the primary coolant along with helium gas and dust, resulting in an increase in the radioactive content of the coolant, and there is a risk of radioactive leakage.

[0008] 3. Increase in graphite dust content: Graphite dust is a unique problem in high-temperature gas-cooled reactors. Friction between graphite balls and between graphite balls and the internal components of the carbon pile will generate graphite dust. Broken balls will generate more graphite dust, and the deposition of graphite dust will reduce the strength of the internal components of the reactor and increase the pressure on the graphite dust filtration system. Summary of the Invention

[0009] The purpose of the present invention is to overcome the above-mentioned disadvantages of the prior art and provide a system and method for staged loading of a high-temperature gas-cooled reactor, which can reduce the impact generated by the dropping of graphite balls.

[0010] To achieve the above purpose, the system for staged loading of a high-temperature gas-cooled reactor described in the present invention includes a graphite ball temporary storage tank, a valve for the graphite ball loading pipe at the top of the reactor core, a valve for the graphite ball loading pipe in the middle of the reactor core, a high-temperature reactor core chamber, a graphite ball position detector, and a control system;

[0011] The outlet of the graphite ball temporary storage tank is connected to one end of the valve for the graphite ball loading pipe at the top of the reactor core and one end of the valve for the graphite ball loading pipe in the middle of the reactor core. The other end of the valve for the graphite ball loading pipe at the top of the reactor core is connected to the top inlet of the high-temperature reactor core chamber, and the other end of the valve for the graphite ball loading pipe in the middle of the reactor core is connected to the side inlet of the high-temperature reactor core chamber. A graphite ball position detector is arranged on the inner wall of the high-temperature reactor core chamber, and the output end of the graphite ball position detector is connected to the input end of the control system. The output end of the control system is connected to the control ends of the valve for the graphite ball loading pipe at the top of the reactor core and the valve for the graphite ball loading pipe in the middle of the reactor core.

[0012] The valve for the graphite ball loading pipe at the top of the reactor core is connected to the top inlet of the high-temperature reactor core chamber through the graphite ball loading pipe at the top of the reactor core.

[0013] The valve for the graphite ball loading pipe in the middle of the reactor core is connected to the side inlet of the high-temperature reactor core chamber through the graphite ball loading pipe in the middle of the reactor core.

[0014] The output end of the graphite ball position detector is connected to the input end of the control system through the graphite ball position detector signal transmission line.

[0015] The bottom outlet of the high-temperature reactor core chamber is connected to the graphite ball discharge pipe through the graphite ball discharge pipe valve.

[0016] The bottom outlet of the high-temperature reactor core chamber is connected to a graphite ball discharge pipe.

[0017] The distance between the graphite ball position detector and the bottom of the high-temperature reactor core chamber is two-fifths of the height of the high-temperature reactor core chamber.

[0018] A method for staged loading of a high-temperature gas-cooled reactor includes the following steps:

[0019] Load the graphite balls into the graphite ball temporary storage box. When charging is required, open the valve of the graphite ball charging pipe in the middle of the core, so that the graphite balls in the graphite ball temporary storage box enter the high-temperature reactor core chamber through the valve of the graphite ball charging pipe in the middle of the core. Real-time detection of the height of the graphite balls in the high-temperature reactor core chamber is carried out through the graphite ball position detector. When the height of the graphite balls filled in the high-temperature reactor core chamber reaches the preset height, close the valve of the graphite ball charging pipe in the middle of the core and open the valve of the graphite ball charging pipe at the top of the core, so that the graphite balls in the graphite ball temporary storage box enter the high-temperature reactor core chamber through the valve of the graphite ball charging pipe at the top of the core.

[0020] The present invention has the following beneficial effects:

[0021] When the system and method for staged charging of the high-temperature gas-cooled reactor according to the present invention are specifically operated, first send graphite balls through the inlet on the side of the high-temperature reactor core chamber. After waiting for the height of the graphite balls in the high-temperature reactor core chamber to reach the preset height, then send graphite balls through the inlet at the top of the high-temperature reactor core chamber. The impact of the graphite balls on the high-temperature reactor core chamber is small, avoiding the problems of impact on in-core components and broken balls during the initial fuel loading. The structure is simple, the operation is convenient, and the practicability is extremely strong. Description of the Drawings

[0022] Figure 1 It is a schematic structural diagram of the present invention.

[0023] Among them, 1 is the graphite ball temporary storage box, 2 is the valve of the graphite ball charging pipe at the top of the core, 3 is the valve of the graphite ball charging pipe in the middle of the core, 4 is the high-temperature reactor core chamber, 5 is the signal transmission line of the graphite ball position detector, 6 is the valve of the graphite ball discharge pipe, 7 is the graphite ball position detector, 8 is the control system, 9 is the graphite ball charging pipe at the top of the core, 10 is the graphite ball charging pipe in the middle of the core, and 11 is the graphite ball discharge pipe. Specific Embodiments

[0024] In order to enable those skilled in the art of the present technology to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments, and are not intended to limit the scope of the present invention disclosed. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessarily confusing the concepts disclosed in the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0025] A schematic structural diagram according to an exemplary embodiment of the present invention is shown in the accompanying drawings. These figures are not drawn to scale, and for the purpose of clear illustration, some details are enlarged and some details may be omitted. The shapes of various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary. In practice, there may be deviations due to manufacturing tolerances or technical limitations, and those skilled in the art can design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0026] Referring to Figure 1 , the system for staged loading of a high-temperature gas-cooled reactor according to the present invention includes a graphite ball temporary storage tank 1, a valve 2 for the graphite ball loading pipe at the top of the reactor core, a valve 3 for the graphite ball loading pipe in the middle of the reactor core, a high-temperature reactor core chamber 4, a signal transmission line 5 for the graphite ball position detector, a valve 6 for the graphite ball discharge pipe, a graphite ball position detector 7, a control system 8, a graphite ball loading pipe 9 at the top of the reactor core, a graphite ball loading pipe 10 in the middle of the reactor core, and a graphite ball discharge pipe 11;

[0027] The outlet of the graphite ball temporary storage tank 1 is connected to one end of the valve 2 for the graphite ball loading pipe at the top of the reactor core and one end of the valve 3 for the graphite ball loading pipe in the middle of the reactor core. The other end of the valve 2 for the graphite ball loading pipe at the top of the reactor core is connected to the top inlet of the high-temperature reactor core chamber 4 through the graphite ball loading pipe 9 at the top of the reactor core. The other end of the valve 3 for the graphite ball loading pipe in the middle of the reactor core is connected to the side inlet of the high-temperature reactor core chamber 4 through the graphite ball loading pipe 10 in the middle of the reactor core. A graphite ball position detector 7 is provided on the inner wall of the high-temperature reactor core chamber 4. Among them, the output end of the graphite ball position detector 7 is connected to the input end of the control system 8 through the signal transmission line 5 for the graphite ball position detector. The output end of the control system 8 is connected to the control ends of the valve 2 for the graphite ball loading pipe at the top of the reactor core and the valve 3 for the graphite ball loading pipe in the middle of the reactor core. The bottom outlet of the high-temperature reactor core chamber 4 is connected to the graphite ball discharge pipe 11 through the valve 6 for the graphite ball discharge pipe.

[0028] The distance between the graphite ball position detector 7 and the bottom of the high-temperature reactor core chamber 4 is two-fifths of the height of the high-temperature reactor core chamber 4.

[0029] The method for staged loading of a high-temperature gas-cooled reactor according to the present invention includes the following steps:

[0030] Load new graphite balls into the graphite ball temporary storage tank 1. After the parameters in the core are normal, open the graphite ball loading pipe valve 3 in the middle of the core, so that the graphite balls in the graphite ball temporary storage tank 1 enter the high-temperature reactor core chamber 4 through the graphite ball loading pipe valve 3 in the middle of the core and the graphite ball loading pipe 10 in the middle of the core. The height of the graphite balls in the high-temperature reactor core chamber 4 is detected in real time by the graphite ball position detector 7. When the height of the graphite balls filled in the high-temperature reactor core chamber 4 reaches the preset height, close the graphite ball loading pipe valve 3 in the middle of the core and open the graphite ball loading pipe valve 2 at the top of the core, so that the graphite balls in the graphite ball temporary storage tank 1 enter the high-temperature reactor core chamber 4 through the graphite ball loading pipe valve 2 at the top of the core and the graphite ball loading pipe 9 at the top of the core.

[0031] It should be noted that in the present invention, graphite balls are first fed through the inlet on the side of the high-temperature reactor core chamber 4. After waiting for the height of the graphite balls in the high-temperature reactor core chamber 4 to reach the preset height, graphite balls are fed through the inlet at the top of the high-temperature reactor core chamber 4. The impact of the graphite balls on the high-temperature reactor core chamber 4 is relatively small, avoiding the problems of impact on in-core components and broken balls during the initial fuel loading.

[0032] The present invention has the following characteristics:

[0033] 1) During the initial fuel loading, the in-core components are less impacted: The graphite ball loading pipe valve 3 in the middle of the core is used for the preliminary fuel loading. Since the distance from the middle of the core to the bottom of the core is relatively close, the speed of the graphite balls falling to the bottom of the core is relatively small, and the impact on the in-core components during the initial fuel loading is also relatively small.

[0034] 2) Reduce the radioactive leakage caused by broken balls: By using the graphite ball loading pipe 9 at the top of the core and the graphite ball loading pipe 10 in the middle of the core to switch the fuel loading, the exposure of the fuel particles coated and dispersed inside the graphite balls due to broken balls can be effectively reduced, and the radioactive leakage caused by broken balls can be reduced.

[0035] 3) Reduce the graphite dust content in the primary loop: By using the graphite ball loading pipe 9 at the top of the core and the graphite ball loading pipe 10 in the middle of the core to switch the fuel loading, since the number of broken graphite balls decreases, the amount of graphite dust generated by the broken graphite balls will also decrease.

Claims

1. A system for staged fuel loading of a high-temperature gas-cooled reactor, characterized in that, It includes a graphite ball temporary storage tank (1), a graphite ball loading pipe valve at the top of the core (2), a graphite ball loading pipe valve in the middle of the core (3), a high-temperature reactor core chamber (4), a graphite ball position detector (7), and a control system (8); The outlet of the graphite ball temporary storage tank (1) is connected to one end of the graphite ball loading pipe valve at the top of the core (2) and one end of the graphite ball loading pipe valve in the middle of the core (3). The other end of the graphite ball loading pipe valve at the top of the core (2) is communicated with the top inlet of the high-temperature reactor core chamber (4). The other end of the graphite ball loading pipe valve in the middle of the core (3) is communicated with the side inlet of the high-temperature reactor core chamber (4). A graphite ball position detector (7) is arranged on the inner wall of the high-temperature reactor core chamber (4). The output end of the graphite ball position detector (7) is connected to the input end of the control system (8). The output end of the control system (8) is connected to the control ends of the graphite ball loading pipe valve at the top of the core (2) and the graphite ball loading pipe valve in the middle of the core (3); The graphite ball loading pipe valve at the top of the core (2) is communicated with the top inlet of the high-temperature reactor core chamber (4) through the graphite ball loading pipe at the top of the core (9); The graphite ball loading pipe valve in the middle of the core (3) is communicated with the side inlet of the high-temperature reactor core chamber (4) through the graphite ball loading pipe in the middle of the core (10).

2. The system for staged fuel loading of a high-temperature gas-cooled reactor according to claim 1, characterized in that, The output end of the graphite ball position detector (7) is connected to the input end of the control system (8) through the graphite ball position detector signal transmission line (5).

3. The system for staged fuel loading of a high-temperature gas-cooled reactor according to claim 1, characterized in that, The bottom outlet of the high-temperature reactor core chamber (4) is communicated with the graphite ball discharge pipe (11) through the graphite ball discharge pipe valve (6).

4. The system for staged fuel loading of a high-temperature gas-cooled reactor according to claim 1, characterized in that, The bottom outlet of the high-temperature reactor core chamber (4) is communicated with a graphite ball discharge pipe (11).

5. The system for staged fuel loading of a high-temperature gas-cooled reactor according to claim 4, characterized in that, The bottom outlet of the high-temperature reactor core chamber (4) is communicated with the graphite ball discharge pipe (11) through the graphite ball discharge pipe valve (6).

6. The system for staged fuel loading of a high-temperature gas-cooled reactor according to claim 1, characterized in that, The distance between the graphite ball position detector (7) and the bottom of the high-temperature reactor core chamber (4) is two-fifths of the height of the high-temperature reactor core chamber (4).

7. A method for staged fuel loading of a high-temperature gas-cooled reactor, characterized in that, Based on the system for staged loading of a high-temperature gas-cooled reactor according to claim 1, it includes the following steps: Load graphite balls into the graphite ball temporary storage tank (1). When loading is required, open the graphite ball loading pipe valve in the middle of the core (3) so that the graphite balls in the graphite ball temporary storage tank (1) enter the high-temperature reactor core chamber (4) through the graphite ball loading pipe valve in the middle of the core (3). Real-time detect the height of the graphite balls in the high-temperature reactor core chamber (4) through the graphite ball position detector (7). When the height of the graphite balls filled in the high-temperature reactor core chamber (4) reaches the preset height, then close the graphite ball loading pipe valve in the middle of the core (3) and open the graphite ball loading pipe valve at the top of the core (2) so that the graphite balls in the graphite ball temporary storage tank (1) enter the high-temperature reactor core chamber (4) through the graphite ball loading pipe valve at the top of the core (2).

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