Thermo-acoustic conversion micro-reactor with heat preservation function and operation method of thermo-acoustic conversion micro-reactor

Abstract

The embodiment of the invention provides a thermo-acoustic conversion micro reactor with a heat preservation function and an operation method thereof, and relates to the field of nuclear reactors. The thermo-acoustic conversion micro reactor with the heat preservation function comprises an outer shell and an inner shell, the inner shell is sleeved with the outer shell at intervals, and a fuel area, a sound capacity area, a conduction area and a power generation area which are sequentially arranged are formed in an inner cavity of the inner shell. In the working process, the fuel area can generate sound waves besides heat radiation, the sound waves can sequentially pass through the acoustic capacitance area and the conduction area and then are converted into electric energy in the power generation area, meanwhile, the outer shell can reflect heat radiation flowing out of the inner shell towards the fuel area, more heat is concentrated in the fuel area, and therefore the thermoacoustic power generation effect is improved; heat is gathered and converted into electric energy, and heat loss is reduced while heat preservation is achieved.

Description

Technical Field

[0001] The present invention relates to the field of nuclear reactors, and in particular to a thermoacoustic conversion micro-reactor with a heat preservation function and an operation method thereof. Background Art

[0002] During the operation of a nuclear reactor, cooling gas is usually used to absorb the heat generated in the fuel zone and then take it out to generate electricity. However, there is a problem of excessive heat loss during the energy conversion process, which reduces the energy conversion efficiency. Summary of the invention

[0003] The present invention provides a thermoacoustic conversion micro-pile with a heat preservation function and an operation method thereof, which can utilize the thermoacoustic effect to perform energy conversion, reduce energy loss, and thus improve conversion efficiency.

[0004] The embodiments of the present invention can be implemented as follows:

[0005] An embodiment of the present invention provides a thermoacoustic conversion micro-pile with a heat preservation function, which includes:

[0006] an outer shell and an inner shell;

[0007] Among them, the outer shell is sleeved on the inner shell at intervals, and the inner cavity of the inner shell is formed with a fuel area, a sound capacity area, a conduction area and a power generation area arranged in sequence. The fuel area is used to react and generate heat radiation and sound waves, the sound capacity area is used to receive and enhance sound waves, the conduction area is used to receive the enhanced sound waves and convert them into mechanical energy, the power generation area is used to convert mechanical energy into electrical energy, and the outer shell is used to receive the heat radiation emitted by the inner shell and reflect it toward the fuel area.

[0008] Optionally, a reflective layer is provided on the inner wall of the outer shell, and the reflective layer is made of photonic crystal material.

[0009] Optionally, the reflective layer includes a first reflective segment and a second reflective segment arranged at an angle, the first reflective segment being used to receive the thermal radiation emitted by the fuel zone and reflect toward the fuel zone, and the second reflective segment being used to receive the thermal radiation emitted by the acoustic capacitance zone and / or the conduction zone and / or the power generation zone and reflect toward the fuel zone.

[0010] Optionally, the thickness of the second reflective layer gradually decreases in a direction away from the fuel zone.

[0011] Optionally, the inner shell has an air inlet and an air outlet, the air inlet is located on a side of the fuel zone away from the acoustic capacity zone, and the air outlet is located between the fuel zone and the acoustic capacity zone, and the air inlet is used to input cooling gas to absorb heat energy generated by the fuel zone and generate sound waves.

[0012] Optionally, the thermoacoustic conversion micro-pile with heat preservation function further includes an inertial zone, wherein the inertial zone is located between the acoustic capacity zone and the conductive zone, and the inner diameter of the inertial zone is smaller than the inner diameter of the acoustic capacity zone.

[0013] Optionally, the acoustic capacity area is provided with a bottom plate and a plurality of straight tubes, the bottom plate is provided with guide holes communicating with the plurality of straight tubes, and the guide holes and the inner cavities of the straight tubes together define an acoustic capacity channel.

[0014] Optionally, the conductive area is a metal bellows.

[0015] Optionally, the power generation area is provided with a generator and a piston rod, one end of the piston rod is connected to the metal bellows, and the other end of the piston rod is connected to the generator.

[0016] The embodiment of the present invention further provides an operation method of a thermoacoustic conversion micro-pile with a heat preservation function, which is implemented by the thermoacoustic conversion micro-pile with a heat preservation function. The operation method of the thermoacoustic conversion micro-pile with a heat preservation function includes:

[0017] Controlling the fuel zone to react and generate heat radiation and sound waves;

[0018] Controlling the acoustic capacitance area to conduct the sound wave to the conduction area;

[0019] Controlling the conduction area to convert the sound waves into mechanical energy, and then controlling the power generation area to convert the mechanical energy into electrical energy;

[0020] The outer shell is controlled to receive the electric radiation emitted by the inner shell and reflect it toward the fuel area.

[0021] The beneficial effects of the thermoacoustic conversion micro-pile with heat preservation function and the operation method thereof according to the embodiment of the present invention include, for example:

[0022] The thermoacoustic conversion micro-pile with heat preservation function includes an outer shell and an inner shell; wherein the outer shell is sleeved on the inner shell at intervals, and the inner cavity of the inner shell is formed with a fuel area, an acoustic volume area, a conduction area and a power generation area arranged in sequence, the fuel area is used to react and generate heat radiation and sound waves, the acoustic volume area is used to receive and enhance sound waves, the conduction area is used to receive the enhanced sound waves and convert them into mechanical energy, the power generation area is used to convert mechanical energy into electrical energy, and the outer shell is used to receive the heat radiation emitted by the inner shell and reflect it toward the fuel area. During operation, the fuel area can generate sound waves in addition to heat radiation, and the sound waves can pass through the acoustic volume area and the conduction area in sequence and then be converted into electrical energy in the power generation area. At the same time, the outer shell can reflect the heat radiation flowing out of the inner shell toward the fuel area, which plays a role in heat preservation while reducing heat loss, thereby improving energy conversion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 A schematic diagram of the structure of a thermoacoustic conversion micro-pile with a heat preservation function provided in an embodiment of the present invention;

[0025] Figure 2 A schematic diagram of the operation of a thermoacoustic conversion micro-pile with a heat preservation function provided in an embodiment of the present invention;

[0026] Figure 3 It is a schematic diagram of the structure of the acoustic capacitance area provided in an embodiment of the present invention.

[0027] Icons: 100-thermoacoustic conversion micro-pile with heat preservation function; 110-outer shell; 115-reflection layer; 116-first reflection section; 117-second reflection section; 120-vacuum chamber; 130-inner shell; 131-air inlet; 132-air outlet; 140-fuel area; 150-acoustic capacity area; 151-bottom plate; 152-guide hole; 153-straight cylinder; 160-conduction area; 170-power generation area; 171-generator; 173-piston rod; 180-inertia area. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, 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 part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0029] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0031] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. appear to indicate an orientation or position relationship, they are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0032] In addition, the terms “first”, “second”, etc., if used, are merely used to distinguish between the descriptions and should not be understood as indicating or implying relative importance.

[0033] The terms "comprises," "comprising," or any other variation thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0034] Unless otherwise clearly specified and limited, the terms "disposed", "connected" and the like should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] It should be noted that, in the absence of conflict, the features in the embodiments of the present invention may be combined with each other.

[0036] As mentioned in the background art, during the operation of a nuclear reactor, cooling gas is usually used to absorb the heat generated in the fuel zone and then taken out to generate electricity. However, there is a problem of excessive heat loss during the energy conversion process, which reduces the energy conversion efficiency.

[0037] Please refer to Figure 1 and Figure 2 The thermoacoustic conversion micro-pile 100 with heat preservation function provided in the embodiment of the present invention can solve the above problems, which will be described in detail below.

[0038] The thermoacoustic conversion micro-pile 100 with heat preservation function includes an outer shell 110 and an inner shell 130;

[0039] Among them, the outer shell 110 is arranged in an interval in the inner shell 130, and the inner cavity of the inner shell 130 is formed with a fuel area 140, an acoustic capacity area 150, a conduction area 160 and a power generation area 170 arranged in sequence. The fuel area 140 is used to react and generate heat radiation and sound waves, the acoustic capacity area 150 is used to receive and enhance sound waves, the conduction area 160 is used to receive the enhanced sound waves and convert them into mechanical energy, the power generation area 170 is used to convert mechanical energy into electrical energy, and the outer shell 110 is used to receive the heat radiation emitted by the inner shell 130 and reflect it toward the fuel area 140.

[0040] During operation, the fuel zone 140 can generate sound waves in addition to heat radiation. The sound waves can pass through the acoustic capacitance zone 150 and the conduction zone 160 in sequence and then be converted into electrical energy in the power generation zone 170. At the same time, the outer shell 110 can reflect the heat radiation flowing out of the inner shell 130 toward the fuel zone 140, thereby playing a role in heat preservation while reducing heat loss, thereby improving energy conversion efficiency.

[0041] It is worth noting that during the reaction process, the fuel zone 140 has a certain temperature difference, the temperature of the bottom end (i.e., the end away from the acoustic volume zone 150) is relatively low, and the temperature of the top end (i.e., the end close to the acoustic volume zone 150) is relatively high. In addition, because the cooling gas is a fluid, when it passes through the fuel zone 140 with a temperature difference, the density and pressure of the cooling gas will change, resulting in the generation of sound waves, which can be understood as the thermoacoustic effect.

[0042] In addition to using the fuel zone 140's own thermal energy to generate electricity, the thermoacoustic conversion micro-pile 100 with heat preservation function can also use the temperature difference of the fuel zone 140 to generate sound waves through the thermoacoustic effect and transmit them to the power generation zone 170 for power generation, thereby further improving the power generation efficiency.

[0043] Please refer to Figure 1 and Figure 2 In order to reduce the heat loss between the inner shell 130 and the outer shell 110, a vacuum cavity 120 can be formed between the inner shell 130 and the outer shell 110. The thermal conductivity of the vacuum cavity 120 is almost 0, and the only heat transfer method is thermal radiation, thereby achieving the thermal insulation effect on the inner shell 130 through thermal radiation.

[0044] Please refer to Figure 1 and Figure 2 In order to improve the heat preservation effect of the inner shell 130, a reflective layer 115 can be provided on the inner wall of the outer shell 110, and the reflective layer 115 is made of photonic crystal material.

[0045] Photonic crystals are periodic materials that can control the propagation and propagation characteristics of light. The uniqueness of this material comes from its internal microstructure, which can prohibit the propagation of light at specific wavelengths, thereby achieving light regulation. Photonic crystals can form a "photonic band gap", similar to the electronic band gap in semiconductors. A photonic band gap refers to the inability of photons to propagate in a material within a certain frequency range. This property makes photonic crystals exhibit very strong reflection and low loss at specific wavelengths.

[0046] In this embodiment, the reflective layer 115 includes a first reflective segment 116 and a second reflective segment 117 which are arranged at an angle. The first reflective segment 116 is used to receive the thermal radiation emitted by the fuel zone 140 and reflect it toward the fuel zone 140. The second reflective segment 117 is used to receive the thermal radiation emitted by the acoustic capacitance zone 150, the conduction zone 160 and the power generation zone 170 and reflect it toward the fuel zone 140.

[0047] Furthermore, since the heat radiation is lower at a position relatively far from the fuel zone 140, in order to reduce material costs, the thickness of the second reflective segment 117 can be gradually reduced in a direction away from the fuel zone 140, and the thickness of the second reflective segment 117 at one end close to the fuel zone 140 is the thickest. Regarding the thickness of the first reflective segment 116, the thickness can be uniform and the same as the thickness of the second reflective segment 117 at one end close to the fuel zone 140.

[0048] In this embodiment, the outer shell 110 can be made to have a structure that is thick in the middle and thin at both ends, that is, the top end of the first reflection segment 116 is connected to the second reflection segment 117, and the bottom end of the first reflection segment 116 is connected to the third reflection segment, and the second reflection segment 117 and the third reflection segment are both inclined inwardly relative to the first reflection segment 116.

[0049] Please refer to Figure 1 and Figure 2 In order to facilitate the flow of cooling gas, the inner shell 130 can be provided with an air inlet 131 and an air outlet 132. The air inlet 131 is located on the side of the fuel zone 140 away from the acoustic capacity zone 150, and the air outlet 132 is located between the fuel zone 140 and the acoustic capacity zone 150. The air inlet 131 is used to input cooling gas to absorb the heat energy generated by the fuel zone 140 and generate sound waves.

[0050] Similarly, the outer shell 110 is provided with an inlet and outlet passage for the cooling gas to pass in and out.

[0051] During operation, the cooling gas may enter the fuel zone 140 through the air inlet 131, move along the fuel zone 140 from the bottom to the top, and then move out through the air outlet 132, and pass through the outer shell 110, taking away the heat for conversion into electrical energy.

[0052] Please refer to Figure 1 and Figure 3 The acoustic capacitance area 150 is provided with a bottom plate 151 and a plurality of straight tubes 153 . The bottom plate 151 is provided with guide holes 152 connected to the plurality of straight tubes 153 . The guide holes 152 and the inner cavities of the straight tubes 153 together define an acoustic capacitance channel.

[0053] It should be noted that the acoustic volume 150 usually has a specific collective shape, and its size and shape match the operating frequency to form an acoustic wave resonance cavity, thereby enhancing the energy of the acoustic wave so that the acoustic wave is strengthened when propagating therein.

[0054] In this embodiment, the bottom plate 151 is in the shape of a circular plate, the axial cross section of the straight tube 153 is circular, and the guide hole 152 is a circular hole. The straight tube 153 is connected to the top of the bottom plate 151, and the number of straight tubes 153 connected to a single bottom plate 151 is multiple, and the multiple supports are arranged in multiple groups along the circumference of the bottom plate 151, and the number of straight tubes 153 in different groups gradually decreases along the center position close to the bottom plate 151.

[0055] Of course, in other embodiments of the present invention, the bottom plate 151 may be a rectangular plate, a triangular plate or a prismatic plate structure, etc., the axial cross-section of the straight cylinder 153 may also be rectangular, triangular or prismatic, etc., and the corresponding guide hole 152 may also be a rectangular hole, a triangular hole or a prismatic hole, etc. The specific shapes of the bottom plate 151, the axial cross-section of the straight cylinder 153 and the guide hole 152 are not limited.

[0056] Please refer to Figure 1 and Figure 2 The thermoacoustic conversion micro-pile 100 with heat preservation function also includes an inertial zone 180 . The inertial zone 180 is located between the acoustic capacity zone 150 and the conductive zone 160 . The inner diameter of the inertial zone 180 is smaller than the inner diameter of the acoustic capacity zone 150 .

[0057] It is worth noting that the inertial zone 180 mainly affects the compression and expansion speed of the gas, so as to achieve stable sound wave propagation and heat transfer; at the same time, it can balance the control of the flow speed and pressure of the gas. By controlling the gas flow in the inertial zone 180, the propagation of sound waves and energy exchange inside the equipment can be optimized, thereby improving the efficiency of thermoacoustic power generation.

[0058] Furthermore, the inner diameter of the acoustic capacitance zone 150 can be understood as the combined inner diameters of all acoustic capacitance channels. The inertial zone 180 has only one conducting channel, which corresponds to the acoustic capacitance channel located at the center of the acoustic capacitance zone 150 .

[0059] Please refer to Figure 1 and Figure 2The conduction area 160 is a metal bellows, which can transmit and adjust the pressure fluctuation of the sound wave during operation, and convert the heat energy into the mechanical energy of the piston rod 173 by exciting the vibration of the bellows by high temperature. At the same time, the elastic design of the metal bellows can effectively alleviate and absorb the changes in the expansion of the equipment caused by high temperature, and avoid the influence of thermal expansion on the equipment.

[0060] Please refer to Figure 1 and Figure 2 The power generation area 170 is provided with a generator 171 and a piston rod 173, one end of the piston rod 173 is connected to the metal bellows, and the other end of the piston rod 173 is connected to the generator 171. When the metal bellows vibrates, it can drive the piston rod 173 to move axially, thereby driving the generator 171 to convert mechanical energy into electrical energy to achieve power generation.

[0061] The embodiment of the present invention further provides an operation method of a thermoacoustic conversion micro-pile with a heat preservation function, which is implemented by the thermoacoustic conversion micro-pile 100 with a heat preservation function. The method includes:

[0062] Step S100: controlling the fuel zone 140 to react and generate heat radiation and sound waves;

[0063] Step S210: Control the acoustic capacitance area 150 to conduct sound waves to the conduction area 160;

[0064] Step S220: controlling the conduction area 160 to convert the sound waves into mechanical energy, and then controlling the power generation area 170 to convert the mechanical energy into electrical energy;

[0065] Step S310 : controlling the outer shell 110 to receive the electrical radiation emitted by the inner shell 130 and reflect it toward the fuel area 140 .

[0066] It is worth noting that the above step S310 can be performed simultaneously with step S210 and step S220.

[0067] In summary, the thermoacoustic conversion micro-pile 100 with a heat preservation function and the operation method of the thermoacoustic conversion micro-pile with a heat preservation function provided by the embodiments of the present invention have at least the following advantages:

[0068] (1) The fuel zone 140 of the thermoacoustic conversion micro-pile 100 with insulation function can generate sound waves in addition to thermal radiation. The sound waves can pass through the acoustic capacitance zone 150 and the conduction zone 160 in sequence and then be converted into electrical energy in the power generation zone 170. At the same time, the outer shell 110 can reflect the thermal radiation flowing out of the inner shell 130 toward the fuel zone 140, thereby playing a role in insulation and reducing heat loss, thereby improving energy conversion efficiency.

[0069] (2) The thermoacoustic conversion micro-pile 100 with heat preservation function can reflect the heat radiation emitted from the inner shell 130 of the pile through the reflection layer 115 arranged on the inner wall of the outer shell 110, so that the reflected heat radiation is concentrated in the fuel area 140, thereby improving the heat preservation effect of the fuel area 140 and reducing heat loss.

[0070] (3) The thermoacoustic conversion micro-stack 100 with heat preservation function helps to increase the temperature difference between the two ends of the fuel zone 140 by reflecting and focusing the heat to the fuel zone 140, thereby promoting the thermoacoustic effect, so that the mechanical energy caused by the generated sound waves through the conduction zone 160 is greater, and then converted into more electrical energy by the power generation zone 170.

[0071] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A thermoacoustic conversion micro-pile with heat preservation function, characterized in that: include: An outer shell (110) and an inner shell (130); The outer shell (110) is sleeved on the inner shell (130) at intervals, and the inner cavity of the inner shell (130) is formed with a fuel area (140), an acoustic capacity area (150), a conduction area (160) and a power generation area (170) arranged in sequence. The fuel area (140) is used to react and generate heat radiation and sound waves, the acoustic capacity area (150) is used to receive and enhance sound waves, the conduction area (160) is used to receive the enhanced sound waves and convert them into mechanical energy, the power generation area (170) is used to convert mechanical energy into electrical energy, and the outer shell (110) is used to receive the heat radiation emitted by the inner shell (130) and reflect it toward the fuel area (140).

2. The thermoacoustic conversion micro-pile with heat preservation function according to claim 1, characterized in that: The inner wall of the outer shell (110) is provided with a reflection layer (115), and the reflection layer (115) is made of photonic crystal material.

3. The thermoacoustic conversion micro-pile with heat preservation function according to claim 2, characterized in that: The reflective layer (115) comprises a first reflective segment (116) and a second reflective segment (117) which are arranged at an angle, wherein the first reflective segment (116) is used to receive the thermal radiation emitted by the fuel zone (140) and reflect it toward the fuel zone (140), and the second reflective segment (117) is used to receive the thermal radiation emitted by the acoustic capacitance zone (150) and / or the conduction zone (160) and / or the power generation zone (170) and reflect it toward the fuel zone (140).

4. The thermoacoustic conversion micro-pile with heat preservation function according to claim 3, characterized in that: The thickness of the second reflecting section (117) gradually decreases in a direction away from the fuel zone (140).

5. The thermoacoustic conversion micro-pile with heat preservation function according to any one of claims 1 to 4, characterized in that: The inner shell (130) is provided with an air inlet (131) and an air outlet (132); the air inlet (131) is located on a side of the fuel zone (140) away from the acoustic capacity zone (150); the air outlet (132) is located between the fuel zone (140) and the acoustic capacity zone (150); the air inlet (131) is used to input cooling gas to absorb heat energy generated by the fuel zone (140) and generate sound waves.

6. The thermoacoustic conversion micro-pile with heat preservation function according to any one of claims 1 to 4, characterized in that: The thermoacoustic conversion micro-pile with a heat preservation function further comprises an inertial zone (180), wherein the inertial zone (180) is located between the acoustic capacity zone (150) and the conductive zone (160), and the inner diameter of the inertial zone (180) is smaller than the inner diameter of the acoustic capacity zone (150).

7. The thermoacoustic conversion micro-pile with heat preservation function according to any one of claims 1 to 4, characterized in that: The acoustic capacity area (150) is provided with a bottom plate (151) and a plurality of straight tubes (153); the bottom plate (151) is provided with guide holes (152) connected to the plurality of straight tubes (153); the guide holes (152) and the inner cavities of the straight tubes (153) together define an acoustic capacity channel.

8. The thermoacoustic conversion micro-pile with heat preservation function according to any one of claims 1 to 4, characterized in that: The conducting area (160) is a metal bellows.

9. The thermoacoustic conversion micro-pile with heat preservation function according to claim 8, characterized in that: The power generation area (170) is provided with a generator (171) and a piston rod (173), one end of the piston rod (173) is connected to the metal bellows, and the other end of the piston rod (173) is connected to the generator (171).

10. An operating method of a thermoacoustic conversion micro-pile with a heat preservation function, characterized in that: The method is realized by the thermoacoustic conversion micro-pile with heat preservation function as claimed in any one of claims 1 to 9, and the operation method of the thermoacoustic conversion micro-pile with heat preservation function comprises: Controlling the fuel zone (140) to react and generate heat radiation and sound waves; Controlling the acoustic capacitance area (150) to conduct the acoustic wave to the conduction area (160); Controlling the conduction area (160) to convert the sound waves into mechanical energy, and then controlling the power generation area (170) to convert the mechanical energy into electrical energy; The outer shell (110) is controlled to receive the electric radiation emitted by the inner shell (130) and reflect it toward the fuel area (140).

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