Nuclear fission reactivity control device and nuclear fission reactivity control system

Abstract

The present invention provides a fission reactivity control device comprising: a fission reactivity control unit having a neutron absorber and a neutron reflector that move along a closed-loop trajectory to selectively control fission reactivity within a core, wherein the fission reactivity can be flexibly controlled, and when power is cut off, the absorber material is directed toward the core by gravity or tension to ensure safety of the fission reactivity control device and the fission reactivity control system and minimize space usage; a position control unit connected to the fission reactivity control unit to adjust the positions of the neutron absorber and the neutron reflector along the closed-loop trajectory; and an electric drive unit that provides power to the position control unit to enable positional movement of the neutron absorber and the neutron reflector, wherein the neutron absorber and the neutron reflector are controlled to move up and down along the closed-loop trajectory by the control of the position control unit to face the core or the opposite direction.

Description

Technology Field

[0001] The present invention relates to a device capable of controlling nuclear fission reactivity and a system capable of controlling nuclear fission reactivity. Background Technology

[0002] Nuclear fission reaction control technology is a core technology for stably maintaining and regulating nuclear fission reactions in nuclear reactors. Inside the reactor, uranium ( 235 U) or plutonium ( 239 If fuel such as Pu absorbs neutrons and triggers a chain reaction, heat is generated due to the release of energy. This generated heat can be used to produce steam and rotate turbines to generate electricity. Since failure to properly control the rate of the nuclear fission reaction can destabilize the reactor or cause the reaction to stop, it is important to maintain the balance of the nuclear reaction by controlling the number of neutrons.

[0003] Among these, the nuclear fission reaction control device is made of neutron-absorbing materials including boron, cadmium, and silver, and generally takes the form of a rod or a drum. Control rods can control the rate of the nuclear fission reaction by adjusting the number of neutrons through insertion or withdrawal into the reactor. However, inserting control rods into the core where a high-density fluid flows in a molten salt reactor can cause a loss of control capability for the control rods, and a loss of control capability can also occur under zero-gravity conditions or when the insertion direction of the control rods differs from gravity. Furthermore, when controlling the nuclear fission reactivity using a cylindrical control drum, it occupies a large volume inside the reactor, which may make it difficult to miniaturize the reactor system and control the axial power distribution of the core. Prior art document KR 1605725 B1 discloses the insertion or withdrawal of control rods as an invention relating to a reactor, but does not disclose an improved form of a control rod corresponding to a nuclear fission reaction control device.

[0004] Accordingly, a new type of fission control device and fission control system is required that enables the miniaturization of the fission control system and can control the fission reactivity without the insertion or withdrawal of the fission reaction control device. The problem to be solved

[0005] The objective of the present invention is to provide a fission reactivity control device and a fission reactivity control system capable of dynamically controlling fission reactivity.

[0006] Another objective of the present invention is to ensure the safety of the fission reactivity control device and the fission reactivity control system by causing the absorber material to face the core direction by gravity or tension when the power is cut off.

[0007] Another objective of the present invention is to provide a fission reactivity control device and a fission reactivity control system capable of minimizing space usage.

[0008] Another objective of the present invention is to selectively control the fission reactivity within the core. means of solving the problem

[0009] To achieve the above-mentioned purpose, a fission reactivity control device may be provided, comprising: a fission reactivity control unit having a neutron absorbing unit and a neutron reflecting unit that move along a closed curve orbit; a position control unit connected to the fission reactivity control unit and controlling the position of the neutron absorbing unit and the neutron reflecting unit along the closed curve orbit; and an electric drive unit that provides power to the position control unit to enable the positional movement of the neutron absorbing unit and the neutron reflecting unit, wherein the neutron absorbing unit and the neutron reflecting unit are controlled to move up and down along the closed curve orbit by the control of the position control unit so as to face the core or the opposite direction.

[0010] In addition, the neutron absorbing part and the neutron reflecting part each have one end and the other end, and the one end of the neutron absorbing part is connected to the one end of the neutron reflecting part, and the other end of the neutron absorbing part is connected to the other end of the neutron reflecting part to form a closed curve shape.

[0011] In addition, at least a portion of the neutron absorption section and the neutron reflection section can be controlled through positional shift to face the core or the opposite direction, passing over the upper or lower end of the closed curve orbit.

[0012] In addition, the above-mentioned fission reaction control unit may be extended in the vertical direction by a length corresponding to the vertical length of the core.

[0013] In addition, the neutron absorption unit may include a plurality of neutron absorption units, and the neutron reflection unit may include a plurality of neutron reflection units, wherein the plurality of neutron absorption units may be arranged continuously to form the neutron absorption unit, and the plurality of neutron reflection units may be arranged continuously to form the neutron reflection unit.

[0014] In addition, at least one of the neutron absorbing part and the neutron reflecting part may have a difference in concentration or material, and when there is a difference in concentration or material of the neutron absorbing part, the degree of neutron absorption among the plurality of neutron absorbing units within the neutron absorbing part may differ from each other, and when there is a difference in concentration or material of the neutron reflecting part, the degree of neutron reflection among the plurality of neutron reflecting units within the neutron reflecting part may differ from each other.

[0015] In addition, the fission reactivity control unit may further include a closed-curve shaped support member that supports the neutron absorption unit and the neutron reflection unit to form a boundary between the direction facing the core and the opposite direction, and maintains the closed-curve orbit.

[0016] In addition, to achieve the above-mentioned purpose, a fission reactivity control system may be provided, comprising a core in which a fission reaction occurs, and a plurality of fission reactivity control devices spaced apart from each other along the circumference of the core at a position spaced apart in a radial direction from the core, wherein the fission reactivity control device comprises: a fission reactivity control unit having a neutron absorbing unit and a neutron reflecting unit that moves along a closed curve orbit; a position control unit connected to the fission reactivity control unit to adjust the positions of the neutron absorbing unit and the neutron reflecting unit along the closed curve orbit; and an electric drive unit that provides power to the position control unit to enable the positional movement of the neutron absorbing unit and the neutron reflecting unit, wherein the neutron absorbing unit and the neutron reflecting unit are controlled to move up and down along the closed curve orbit so as to face the core or the opposite direction.

[0017] In addition, if the electric drive unit is not driven due to power loss, its position may be passively changed by gravity or tension, so that the neutron absorber is located in a direction facing the core and the neutron reflector is located in the opposite direction.

[0018] In addition, the plurality of fission reactivity control devices can be controlled independently of each other according to the fission reactivity of the core. Effects of the invention

[0019] The effects of the present invention obtained through the above-described solution are as follows.

[0020] The fission reactivity control device and fission reactivity control system proposed in the present invention can control fission reactivity through the rotatable configuration of the fission reactivity control device and the concentration and material difference of the material constituting the fission reactivity control device.

[0021] In addition, if the power supply within the fission reactivity control device is cut off during the operation of the fission reactivity control system, the safety of the reactor can be induced by gravity or tension causing the absorber material to move toward the core.

[0022] In addition, the fission reactivity control unit of the fission reactivity control device proposed in this invention is in a plate-like form, making it possible to minimize space usage when operating the fission reactivity control device itself and the fission reactivity control system.

[0023] In addition, the fission reactivity control device and fission reactivity control system proposed in the present invention can selectively control the fission reactivity in the upper and lower parts of the core by adjusting the rotation direction of the fission reactivity control device. Brief explanation of the drawing

[0024] FIGS. 1a and FIGS. 1b are conceptual diagrams showing a fission reactivity control device proposed in the present invention. FIGS. 2a and 2b are conceptual diagrams showing the arrangement of the fission reactivity control device proposed in the present invention facing the core. FIGS. 3a and FIGS. 3b are conceptual diagrams showing the fission reactivity control system proposed in the present invention. Specific details for implementing the invention

[0025] Hereinafter, the nuclear fission reaction control device and nuclear fission reaction control system proposed in the present invention will be described in more detail with reference to the drawings.

[0026] In this specification, identical or similar reference numbers are assigned to identical or similar components even in different embodiments, and redundant descriptions thereof are omitted.

[0027] In describing the embodiments disclosed in this specification, if it is determined that a detailed description of related prior art could obscure the essence of the embodiments disclosed in this specification, such detailed description is omitted.

[0028] The attached drawings are intended only to facilitate understanding of the embodiments disclosed in this specification, and the technical concept disclosed in this specification is not limited by the attached drawings; it should be understood that all modifications, equivalents, and substitutions included within the concept and technical scope of the present invention are included.

[0029] In the following description, singular expressions include plural expressions unless the context clearly indicates otherwise.

[0030] In this application, terms such as “comprising” or “having” are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0031] Hereinafter, a fission reactivity control device (100) proposed in the present invention will be described.

[0032] FIGS. 1a and FIGS. 1b are conceptual diagrams showing a fission reactivity control device (100) proposed in the present invention.

[0033] Referring to FIGS. 1a and 1b, the fission reactivity control device (100) proposed in the present invention may include a fission reactivity control unit (110), a position control unit (120), and an electric driving unit (130).

[0034] First, the fission reactivity control unit (110) can move along a closed orbit. Here, a closed orbit refers to an orbit in which an object moves along a certain path and then returns to its original position and circulates repeatedly.

[0035] In the closed-loop orbit of the fission reactivity control unit (110), the straight section may be extended longer than the curved section. Extending the straight section longer than the curved section is intended to increase the degree of reaction with neutrons emitted from the core (C) and to reduce the volume. As the degree of reaction with neutrons increases, the fission reactivity control unit (110) can easily control the fission reactivity.

[0036] The nuclear fission reactivity control unit (110) may be equipped with a neutron absorption unit (111) and a neutron reflection unit (112). The neutron absorption unit (111) and the neutron reflection unit (112) may react with neutrons emitted from the core (C).

[0037] The core (C) refers to the central part of a nuclear reactor that contains nuclear fuel and is where nuclear fission reactions take place, and thermal energy and neutrons can be released through nuclear fission.

[0038] The neutron absorption unit (111) can perform the role of absorbing neutrons emitted from the core (C). Because the absorption of neutrons reduces the number of neutrons that cause nuclear fission, the neutron absorption unit (111) can reduce the nuclear fission reactivity.

[0039] The neutron absorption section (111) may include at least one material among materials with a large neutron absorption cross-section, such as boron carbide and an alloy including silver-indium-cadmium.

[0040] Boron carbide (B4C) is a ceramic compound composed of boron and carbon, of which the boron is the boron-10 isotope ( 10 It contains about 19-20% of B), and the boron-10 isotope can strongly absorb neutrons through a neutron capture reaction. In addition, boron carbide has a high hardness with a Mohs hardness of about 9 to 9.5, is stable at high temperatures, and has excellent wear resistance, so it can be suitable as a material to form the neutron absorption part (111).

[0041] The boron carbide used in the neutron absorption section (111) may be boron carbide having 90 wt% boron and boron carbide having 70 wt% boron. The boron carbide having 90 wt% boron has a higher neutron absorption cross-section and a higher proportion of boron-10 isotopes, so it can absorb more neutrons than the boron carbide having 70 wt% boron.

[0042] Silver-indium-cadmium alloy (Ag-In-Cd) can provide excellent neutron absorption performance through a combination of cadmium (Cd), which has an excellent neutron absorption cross-section; indium (In), which assists in neutron absorption performance and complements the mechanical properties of cadmium; and silver (Ag), which can provide improved mechanical strength and high-temperature stability. Silver-indium-cadmium alloy can maintain stable performance even during long-term use inside a nuclear reactor and can precisely control the reactor's chain reaction by evenly absorbing neutrons.

[0043] In contrast to the neutron absorption section (111), the neutron reflection section (112) can perform the role of reflecting neutrons emitted from the core (C). Since the number of neutrons that will cause nuclear fission increases due to the reflection of neutrons, the neutron reflection section (112) can increase the nuclear fission reactivity.

[0044] The neutron reflection part (112) may include at least one material among materials with a large neutron scattering cross-section, such as beryllium oxide and magnesium oxide.

[0045] Beryllium oxide (BeO) is a compound composed of beryllium (Be) and oxygen (O). Beryllium, which has a low atomic number of 4, can effectively reduce the kinetic energy of neutrons when colliding with them, thereby inducing a deceleration of the neutrons and potentially inducing further nuclear fission. Additionally, neutrons can effectively reflect neutrons by returning without losing energy through elastic scattering after colliding with beryllium oxide.

[0046] Magnesium oxide (MgO) is a compound composed of magnesium (Mg) and oxygen (O). Magnesium, which has a relatively low atomic number of 12, can induce the deceleration and reflection of neutrons upon collision. Additionally, magnesium is relatively inexpensive, allowing for cost-effective neutron reflection, so magnesium oxide can be used as a neutron reflector.

[0047] Meanwhile, the neutron absorption section (111) and the neutron reflection section (112) may have one end and the other end. That is, the neutron absorption section (111) and the neutron reflection section (112) may each have both ends.

[0048] At this time, one end of the neutron absorption section (111) can be connected to one end of the neutron reflection section (112), and the other end of the neutron absorption section (111) can be connected to the other end of the neutron reflection section (112). As both ends of the neutron absorption section (111) and both ends of the neutron reflection section (112) are combined with each other, the nuclear fission reaction control section (110) can form a closed curve shape.

[0049] Additionally, at least a portion of the neutron absorption section (111) and the neutron reflection section (112) can be controlled through positional shifting to face the core (C) or the opposite direction, extending beyond the upper or lower end of the closed curve orbit.

[0050] If a portion of the neutron absorption section (111) and the neutron reflection section (112) moves beyond the upper or lower end of the closed curve orbit through positional movement, the portion of the neutron absorption section (111) and the portion of the neutron reflection section (112) are positioned in a direction facing the core (C), thereby making it possible to selectively control the fission reactivity in the upper and lower parts of the core.

[0051] If the ratio of the neutron absorption section (111) facing the core (C) is higher than the ratio of the neutron reflection section (112) facing the core (C), the nuclear fission reactivity may decrease. On the other hand, if the ratio of the neutron absorption section (111) facing the core (C) is lower than the ratio of the neutron reflection section (112) facing the core (C), the nuclear fission reactivity may increase.

[0052] Additionally, the fission reactivity control unit (110) can be extended in the vertical direction by a length corresponding to the vertical length of the core (C). The vertical extension of the fission reactivity control unit (110) can improve the degree of reaction with neutrons emitted from the core (C), thereby facilitating the control of the fission reactivity.

[0053] Also, the neutron absorption unit (111) may include a plurality of neutron absorption units, and the neutron reflection unit (112) may include a plurality of neutron reflection units.

[0054] As shown in FIGS. 1a and 1b, the neutron absorption section (111) and the neutron reflection section (112) can each be divided into multiple sections, and each section can correspond to a neutron absorption unit or a neutron reflection unit.

[0055] At this time, a plurality of neutron absorption units can be arranged continuously to form a neutron absorption section (111), and a plurality of neutron reflection units can be arranged continuously to form a neutron reflection section (112).

[0056] That is, the neutron absorbing unit and the neutron reflecting unit are not arranged alternately, and multiple neutron absorbing unit can be arranged together, and multiple neutron reflecting unit can be arranged together. As a result, multiple neutron absorbing unit groups can form a neutron absorbing section (111) through a continuous arrangement, and multiple neutron reflecting unit groups can form a neutron reflecting section (112) through a continuous arrangement.

[0057] Meanwhile, at least one of the neutron absorption section (111) and the neutron reflection section (112) may have a difference in concentration or material. The concentration or material of at least one of the neutron absorption section (111) and the neutron reflection section (112) may be uniform to each other internally, but the concentration or material of at least one of the neutron absorption section (111) and the neutron reflection section (112) may have a difference to each other internally.

[0058] If there is a difference in concentration or material of the neutron absorption unit (111), the degree of neutron absorption among multiple neutron absorption units within the neutron absorption unit (111) may differ. Since the neutron absorption unit (111) contains multiple neutron absorption units, the neutron absorption units may have different degrees of neutron absorption. If a neutron absorption unit has a high degree of neutron absorption, the nuclear fission reactivity may decrease due to an increase in the neutron absorption rate, and if a neutron absorption unit has a low degree of neutron absorption, the nuclear fission reactivity may increase due to a decrease in the neutron absorption rate.

[0059] If there is a difference in concentration or material of the neutron reflector (112), the degree of neutron reflection among multiple neutron reflector units within the neutron reflector (112) may differ. Since the neutron reflector (112) contains multiple neutron reflector units, the neutron reflector units may have different degrees of neutron reflection. If a neutron reflector unit has a high degree of neutron reflection, the nuclear fission reactivity may increase due to an increase in neutron reflectance, and if a neutron reflector unit has a low degree of neutron reflection, the nuclear fission reactivity may decrease due to a decrease in neutron reflectance.

[0060] Meanwhile, the fission reaction control unit (110) may further include a support unit (113) in the shape of a closed curve. The support unit (113) may support the neutron absorption unit (111) and the neutron reflection unit (112) to form a boundary in the direction facing the core (C) and the opposite direction, and maintain a closed curve orbit.

[0061] Since the support member (113) corresponds to a structure that supports the neutron absorption member (111) and the neutron reflection member (112), it can be located inside the neutron absorption member (111) and the neutron reflection member (112), and the closed curve shape of the support member (113) can be smaller than the closed curve shape formed by the combination of the neutron absorption member (111) and the neutron reflection member (112).

[0062] The position control unit (120) is connected to the fission reactivity control unit (110) and can control the positions of the neutron absorption unit (111) and the neutron reflection unit (112) in a closed-loop orbit. The position control unit (120) can control the neutron absorption unit (111) and the neutron reflection unit (112) to move in a clockwise or counterclockwise direction.

[0063] Accordingly, at least a portion of the neutron absorption section (111) and the neutron reflection section (112) can be moved by the position control section (120) from a direction facing the core (C) to a direction opposite to the core (C), or from a direction opposite to the core (C) to a direction facing the core (C).

[0064] FIGS. 2a and 2b are conceptual diagrams showing the arrangement of the fission reactivity control device (100) proposed in the present invention facing the core (C).

[0065] Referring to FIGS. 2a and 2b, the neutron absorption section (111) and the neutron reflection section (112) can be controlled by the position control section (120) to move up and down along a closed curved trajectory so as to face the core (C) or the opposite direction.

[0066] First, as shown in FIG. 2a, in order to minimize the nuclear fission reactivity, the neutron absorption section (111) can be positioned facing the core (C) and the neutron reflection section (112) can be positioned opposite to the core (C).

[0067] And as shown in Fig. 2b, to maximize the nuclear fission reactivity, the neutron absorption section (111) can be positioned in a direction opposite to the core (C) and the neutron reflection section (112) can be positioned facing the core (C).

[0068] The electric drive unit (130) can provide power to the position control unit (120) to enable the positional movement of the neutron absorption unit (111) and the neutron reflection unit (112).

[0069] If the electric drive unit (130) is driven, the position control unit (120) can be moved by power, and the positions of the neutron absorption unit (111) and the neutron reflection unit (112) can be adjusted.

[0070] The form of the electric drive unit (130) can be either an electric motor or a pulley.

[0071] If the electric drive unit (130) is in the form of an electric motor, the electric drive unit (130) can be connected to the top of the reactor head, and the position control unit (120) can be extended from the electric drive unit (130) to the upper side of the fission reactivity control unit (110). When the electric drive unit (130) is driven, the position control unit (120) can move up and down to cause the neutron absorption unit (111) and the neutron reflection unit (112) to move up and down.

[0072] If the electric drive unit (130) is not driven, the position control unit (120) cannot be moved by power, and the positions of the neutron absorption unit (111) and the neutron reflection unit (112) can be passively changed by gravity. As a result, the neutron absorption unit (111) can be positioned facing the core (C), and the neutron reflection unit (112) can be positioned opposite to the core (C), making it possible to induce stabilization of the nuclear fission reaction.

[0073] Meanwhile, if the electric drive unit (130) is in the form of a pulley, the position control unit (120) may be connected to the upper side of the nuclear fission reaction control unit (110) as in FIG. 1b, but is not limited thereto. In cases where it is difficult to passively use gravity, a pulley may be a form of the electric drive unit (130) to utilize tension. If the electric drive unit (130) is driven to perform rotational motion, unlike an electric motor, the position control unit (120) can move by the force acting left and right, causing the neutron absorption unit (111) and the neutron reflection unit (112) to move up and down. That is, rotational motion can be converted into up-and-down motion.

[0074] If the electric drive unit (130) is not driven, the position control unit (120) cannot be moved by power, and the positions of the neutron absorption unit (111) and the neutron reflection unit (112) can be passively changed by tension. As a result, the neutron absorption unit (111) can be positioned facing the core (C) and the neutron reflection unit (112) can be positioned opposite to the core (C), making it possible to induce stabilization of the nuclear fission reaction.

[0075] Below, the fission reaction control system (10) proposed in the present invention will be described.

[0076] FIGS. 3a and FIGS. 3b are conceptual diagrams showing a fission reactivity control system (10) proposed in the present invention.

[0077] Referring to FIGS. 3a and 3b, the fission reactivity control system (10) may include a core (C) where a fission reaction occurs and a plurality of fission reactivity control devices (100).

[0078] The core (C) is the central part of the reactor that contains nuclear fuel and can refer to the place where nuclear fission reactions take place, and thermal energy and neutrons can be released through nuclear fission.

[0079] Here, a plurality of fission reactivity control devices (100) can be positioned spaced apart from each other along the circumference of the core (C) at positions spaced apart in the radial direction of the core (C).

[0080] That is, a plurality of fission reactivity control devices (100) can be positioned at locations spaced apart from the core (C) in a direction, and a plurality of fission reactivity control devices (100) can be positioned at locations spaced apart from each other along a circumference longer than the circumference of the upper or lower surface of the core (C). With such a configuration of the fission reactivity control system (10), the space usage of the fission reaction control system (10) can be minimized.

[0081] The fission reactivity control device (100) may include a fission reactivity control unit (110), a position control unit (120), and an electric drive unit (130).

[0082] Although only one configuration including the fission reactivity control unit (110), the position control unit (120), and the electric drive unit (130) is shown as in FIG. 3a and FIG. 3b, other configurations in which only the fission reactivity control unit (110) is shown can also take the form of a fission reactivity control device (100) by combining the position control unit (120) and the electric drive unit (130).

[0083] The fission reactivity control unit (110) can move along a closed curved trajectory. In the closed curved trajectory, the straight section may be extended longer than the curved section. Extending the straight section longer than the curved section is intended to increase the degree of reaction with neutrons emitted from the core (C) and to reduce the volume. As the degree of reaction with neutrons increases, the fission reactivity control unit (110) can easily control the fission reactivity.

[0084] The nuclear fission reaction control unit (110) may be equipped with a neutron absorption unit (111) and a neutron reflection unit (112), and the neutron absorption unit (111) and the neutron reflection unit (112) may react with neutrons emitted from the core (C).

[0085] The neutron absorption unit (111) can perform the role of absorbing neutrons emitted from the core (C). Due to the absorption of neutrons, the neutron absorption unit (111) can reduce the nuclear fission reactivity.

[0086] The neutron absorption section (111) may include at least one material among materials with a large neutron absorption cross-section, such as boron carbide and a silver-indium-cadmium alloy, and the boron carbide used in the neutron absorption section (111) may be boron carbide having 90 wt% boron and boron carbide having 70 wt% boron.

[0087] In contrast to the neutron absorption section (111), the neutron reflection section (112) can perform the role of reflecting neutrons emitted from the core (C). Due to the reflection of neutrons, the neutron reflection section (112) can increase the nuclear fission reactivity.

[0088] The neutron reflection part (112) may include at least one material with a large neutron scattering cross-section, such as beryllium oxide and magnesium oxide.

[0089] Meanwhile, the fission reaction control unit (110) may further include a support unit (113) in the shape of a closed curve. The support unit (113) may support the neutron absorption unit (111) and the neutron reflection unit (112) to form a boundary in the direction facing the core (C) and the opposite direction, and maintain a closed curve orbit.

[0090] The position control unit (120) is connected to the fission reactivity control unit (110) and can control the positions of the neutron absorption unit (111) and the neutron reflection unit (112) in a closed-loop orbit. The position control unit (120) can control the neutron absorption unit (111) and the neutron reflection unit (112) to move in a clockwise or counterclockwise direction.

[0091] Accordingly, at least a portion of the neutron absorption section (111) and the neutron reflection section (112) can be moved by the position control section (120) from a direction facing the core (C) to a direction opposite to the core (C), or from a direction opposite to the core (C) to a direction facing the core (C).

[0092] Additionally, the neutron absorption section (111) and the neutron reflection section (112) can be controlled to move up and down along a closed curved orbit so as to face the core (C) or the opposite direction.

[0093] To minimize the fission reactivity, the neutron absorption section (111) can be positioned facing the core (C), and the neutron reflection section (112) can be positioned opposite to the core (C).

[0094] In addition, to maximize the nuclear fission reactivity, the neutron absorption section (111) can be positioned in a direction opposite to the core (C) and the neutron reflection section (112) can be positioned facing the core (C).

[0095] The electric drive unit (130) can provide power to the position control unit (120) to enable the positional movement of the neutron absorption unit (111) and the neutron reflection unit (112).

[0096] If the electric drive unit (130) is driven, the position control unit (120) can be moved by power, and the positions of the neutron absorption unit (111) and the neutron reflection unit (112) can be adjusted.

[0097] The form of the electric drive unit (130) can be either an electric motor or a pulley.

[0098] If the electric drive unit (130) is in the form of an electric motor, the electric drive unit (130) can be connected to the top of the reactor head, and the position control unit (120) can be extended from the electric drive unit (130) to the upper side of the fission reactivity control unit (110). When the electric drive unit (130) is driven, the position control unit (120) can move up and down to cause the neutron absorption unit (111) and the neutron reflection unit (112) to move up and down.

[0099] Meanwhile, if the electric drive unit (130) is in the form of a pulley, the position control unit (120) may be connected to the upper side of the nuclear fission reaction control unit (110) as shown in FIG. 1b, but is not limited thereto. In cases where it is difficult to passively use gravity, a pulley may be a form of the electric drive unit (130) to utilize tension. If the electric drive unit (130) is driven to perform rotational motion, unlike an electric motor, the position control unit (120) can move by the force acting left and right, causing the neutron absorption unit (111) and the neutron reflection unit (112) to move up and down. That is, rotational motion can be converted into up-and-down motion.

[0100] Meanwhile, if the electric drive unit (130) is not driven due to power loss, the positions of the neutron absorption unit (111) and the neutron reflection unit (112) can be passively varied.

[0101] If the electric drive unit (130) is an electric motor, the position control unit (120) cannot be moved by electric power, and the positions of the neutron absorption unit (111) and the neutron reflection unit (112) can be passively changed by gravity. On the other hand, if the electric drive unit (130) is a pulley, the position control unit (120) cannot be moved by electric power, and the positions of the neutron absorption unit (111) and the neutron reflection unit (112) can be changed by tension.

[0102] In the case where it is not driven due to power loss and gravity or tension is applied, the neutron absorption part (111) may be located in a direction facing the core (C), and the neutron reflection part (112) may be located in a direction opposite to the direction facing the core (C).

[0103] Through this, the nuclear fission reactivity is reduced due to neutron absorption, thereby promoting the stabilization of the nuclear fission reaction.

[0104] In addition, in the nuclear fission reactivity control system (10), a plurality of nuclear fission reactivity control devices (100) can be independently controlled according to the nuclear fission reactivity of the core (C).

[0105] Since the amount of neutrons emitted from the core (C) may differ depending on the location, multiple fission reactivity control devices (100) can stabilize the inside of the reactor by forming different fission reactivity rather than having the same fission reactivity.

[0106] The foregoing description is merely illustrative, and various modifications may be made by those skilled in the art without departing from the scope and technical spirit of the described embodiments. The foregoing embodiments may be implemented individually or in any combination. Explanation of the symbols

[0107] 10: Fission Reactivity Control System 100: Nuclear fission reactivity control device 110: Nuclear fission reactivity control unit 120: Position control unit 130: Electric drive unit C: Core

Claims

Claim 1 A fission reactivity control device comprising: a fission reactivity control unit having a neutron absorbing unit and a neutron reflecting unit that move along a closed curve orbit; a position control unit connected to the fission reactivity control unit to adjust the position of the neutron absorbing unit and the neutron reflecting unit in the closed curve orbit; and an electric drive unit that provides power to the position control unit to enable the positional movement of the neutron absorbing unit and the neutron reflecting unit, wherein the neutron absorbing unit and the neutron reflecting unit are controlled to move up and down along the closed curve orbit by the control of the position control unit so as to face the core or the opposite direction. Claim 2 A nuclear fission reactivity control device according to claim 1, wherein the neutron absorbing part and the neutron reflecting part each have one end and the other end, the one end of the neutron absorbing part is connected to one end of the neutron reflecting part, and the other end of the neutron absorbing part is connected to the other end of the neutron reflecting part to form a closed curve. Claim 3 A fission reactivity control device according to claim 1, wherein at least a portion of the neutron absorption part and the neutron reflection part is controlled to face the core or the opposite direction by shifting its position beyond the upper or lower end of the closed curve orbit. Claim 4 In claim 1, the fission reactivity control unit is a fission reactivity control device that extends in the vertical direction by a length corresponding to the vertical length of the core. Claim 5 A nuclear fission reactivity control device according to claim 4, wherein the neutron absorbing unit comprises a plurality of neutron absorbing units and the neutron reflecting unit comprises a plurality of neutron reflecting units, wherein the plurality of neutron absorbing units are arranged continuously to form the neutron absorbing unit and the plurality of neutron reflecting units are arranged continuously to form the neutron reflecting unit. Claim 6 A nuclear fission reactivity control device according to claim 5, wherein at least one of the neutron absorbing part and the neutron reflecting part has a difference in concentration or material, and when a difference in concentration or material exists in the neutron absorbing part, the degree of neutron absorption among the plurality of neutron absorbing units within the neutron absorbing part is different from each other, and when a difference in concentration or material exists in the neutron reflecting part, the degree of neutron reflection among the plurality of neutron reflecting units within the neutron reflecting part is different from each other. Claim 7 A fission reactivity control device according to claim 1, wherein the fission reactivity control unit further comprises a closed-curve shaped support member that supports the neutron absorption unit and the neutron reflection unit to form a boundary between the direction facing the core and the opposite direction, and maintains the closed-curve orbit. Claim 8 A nuclear fission control system comprising a core in which a nuclear fission reaction occurs, and a plurality of fission reactivity control devices spaced apart from each other along the circumference of the core at a position spaced apart in a radial direction from the core, wherein the fission reactivity control devices include: a fission reactivity control unit having a neutron absorbing unit and a neutron reflecting unit that move along a closed curve orbit; a position control unit connected to the fission reactivity control unit and adjusting the positions of the neutron absorbing unit and the neutron reflecting unit along the closed curve orbit; and an electric drive unit that provides power to the position control unit to enable the positional movement of the neutron absorbing unit and the neutron reflecting unit, wherein the neutron absorbing unit and the neutron reflecting unit are controlled to move up and down along the closed curve orbit so as to face the core or the opposite direction. Claim 9 A fission reactivity control system according to claim 8, wherein when the electric drive unit is not driven due to power loss, the position is passively changed by gravity or tension so that the neutron absorber is located in a direction facing the core and the neutron reflector is located in the opposite direction. Claim 10 A fission reactivity control system according to claim 8, wherein the plurality of fission reactivity control devices are controlled independently of each other according to the fission reactivity of the core.

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