JP2011242169A - In-pile structure of fast reactor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To propose a pressurized water reactor capable of improving uniformity of distribution of coolant flow at the inlet to a reactor core to suppress a change in the flow of coolant that flows into the reactor core.SOLUTION: A fast reactor 1 includes an upper support base 16 and a lower support base 17 that are provided on a body portion 3b of a reactor vessel 3 having a closed-end cylindrical shape; a reactor core 7 that is accommodated in the reactor vessel; a reactor core barrel 8 that surrounds the reactor core 7; a neutron shield 12 that is provided at a position closer to the inner surface of the reactor vessel 3 than the reactor core barrel 8; and a reactor core support structure 15. The reactor core support structure 15 is produced by integrally forming: an annular upper support plate 35 that is fixed on the upper support base 16; a support cylinder 36 that is suspended from an inner edge portion of the upper support plate 35; and a circular lower support plate 37 that is provided at the lower edge portion of the support cylinder 36, is in contact with the lower support base 17, and supports the reactor core 7, reactor core barrel 8 and neutron shield 12.

Description

  Embodiments described herein relate generally to an in-core structure of a fast reactor.

  A conventional fast reactor includes a bottomed cylindrical reactor vessel, a core support plate provided on the lower inner surface of the trunk of the reactor vessel, a reactor core housed in a reactor vessel and configured in a columnar shape, A reactor core that surrounds the reactor core; a partition that surrounds the reactor core; a reflector that is disposed between the reactor core and the partition and moves in the longitudinal direction of the reactor vessel; and that is disposed between the partition and the reactor vessel. A neutron shield that surrounds the reactor core, an upper support plate that holds the top of the neutron shield, and a primary coolant housed in the reactor vessel. The core, the core tank, the bulkhead, and the neutron shield are supported in the reactor vessel by the core support plate.

  Further, the conventional fast reactor includes a fluid drive device and an intermediate heat exchanger that are sequentially arranged above the neutron shield. For example, a fluid drive device configured by an electromagnetic pump or the like generates a flow of a primary coolant in a nuclear reactor vessel. The primary coolant discharged from the fluid drive device descends from the flow path between the partition wall and the reactor vessel to the bottom of the reactor vessel (lower plenum), where it reverses and rises inside the reactor core, Return to the fluid drive through the intermediate heat exchanger and circulate in the reactor vessel. The primary coolant circulated in this way cools the neutron shield and the core sequentially (that is, is heated), and exchanges heat with the secondary coolant in the intermediate heat exchanger. This intermediate heat exchanger has a structure that can be removed from the reactor vessel in consideration of maintenance and inspection.

JP-A-5-119175

  When sodium is used as the coolant, the coolant temperature is assumed to be approximately 350 ° C. to 500 ° C. More specifically, the coolant temperature in the region from the core outlet to the intermediate heat exchanger inlet (hereinafter referred to as “high temperature region”) is about 500 ° C., and the region from the intermediate heat exchanger outlet to the core inlet (hereinafter referred to as “ The coolant temperature in the “low temperature region” is about 350 ° C. In particular, the partition wall that partitions the descending flow path and the ascending flow path of the primary coolant is exposed to a very severe environment because it receives a large pressure difference in addition to the temperature difference between the high temperature region and the low temperature region.

  On the other hand, in the conventional fast reactor, in order to prevent leakage of coolant between the high temperature region and the low temperature region across the intermediate heat exchanger, a bellows pedestal fixed to the partition wall and a seal bellows installed in the intermediate heat exchanger . The conventional fast reactor compresses the seal bellows seated on the bellows pedestal by the weight of the intermediate heat exchanger to block the flow of the primary coolant on the inlet side and the outlet side of the intermediate heat exchanger. However, the seal surface between the bellows pedestal and the seal bellows is not only sealed due to the exposed environmental conditions (temperature difference and pressure difference), but also from manufacturing tolerances such as surface roughness and flatness, and installation tolerances such as parallelism and concentricity. There are challenges in achieving the function. In the fast reactor, when the sealing function at the sealing surface is lost, the coolant in the low temperature region discharged from the fluid drive device flows into the high temperature region at the inlet of the intermediate heat exchanger, and the inlet and outlet of the intermediate heat exchanger There is a problem in functionality that the temperature difference between the two decreases and the heat exchange performance decreases. Such disturbance of the heat balance has a significant effect on the output of the fast reactor, and the flow rate of the coolant to the core is lost, which is a problem in the safety of the fast reactor that the core temperature rises.

  In addition, conventional fast reactors are divided into core structures such as the core support plate, core tank, upper support plate, and bulkhead, so the thermal expansion differences of each core structure and deformation due to earthquakes are taken into account. Thus, there is a problem that structural soundness must be ensured. Furthermore, the fast reactor has a long and complicated and dense structure as a whole, and has many narrow lid portions, so that there is a problem in the installability of these divided in-reactor structures.

  Accordingly, an object of the present invention is to provide an in-furnace structure of a fast reactor that is excellent in functionality, installation property, and structural soundness and has improved reliability.

  In order to solve the above-mentioned problems, a fast reactor internal structure according to the present invention includes a bottomed cylindrical reactor vessel, an upper support provided on an inner surface of a middle portion of the trunk of the reactor vessel, A lower support provided on a lower inner surface of a trunk portion of the reactor vessel; a coolant contained in the reactor vessel; a core contained in the reactor vessel and immersed in the coolant; and the core Is disposed between the inner core of the reactor core, the outer shell of the reactor core surrounding the inner shell of the reactor core, the inner shell of the reactor core and the outer shell of the reactor core, and moves in the longitudinal axis direction of the reactor vessel. A reflector, a neutron shield provided closer to the inner surface of the reactor vessel than the core outer shell, an annular upper support plate fixed to the upper support, and an inner edge of the upper support plate A support cylinder suspended from a lower portion and the lower support provided at a lower end of the support cylinder. A core support structure in which a circular lower support plate that is in contact with a base and supports the core, the core inner shell, the core outer shell, and the neutron shield is integrally formed. It is characterized by that.

  ADVANTAGE OF THE INVENTION According to this invention, the in-core structure of the fast reactor which was excellent in functionality, installation property, and structural soundness, and aimed at the reliability improvement can be provided.

The longitudinal cross-sectional view which showed the in-furnace structure of the fast reactor which concerns on this invention. The typical longitudinal section showing the in-furnace structure of the fast reactor concerning the present invention.

  An embodiment of the in-core structure of a fast reactor according to the present invention will be described with reference to FIG. 1 and FIG.

  FIG. 1 is a longitudinal sectional view showing the in-core structure of a fast reactor according to the present invention.

  The fast reactor 1 shown in FIG. 1 is a nuclear reactor that can be operated continuously for 10 to several decades, for example, about 30 years without replacement of nuclear fuel. The reactor power of the fast reactor 1 is 30 MW to several hundreds MW (electric power 10,000 to 100,000 kW). The fast reactor 1 has an overall height of about 25 m to 35 m, for example about 30 m. The core height of the fast reactor 1 is, for example, about 2.5 m. The coolant is liquid sodium. The temperature of the coolant is equal to or higher than the temperature at which liquid sodium does not solidify, with a margin of 200 ° C. or higher, preferably 300 ° C. to 550 ° C. The temperature of the coolant in each part of the fast reactor 1 is 300 ° C. to 400 ° C. in the coolant channel in the reactor vessel, 350 ° C. as an example, 500 ° C. to 550 ° C. on the core side, and about 500 ° C. as an example. .

  As shown in FIG. 1, the fast reactor 1 is a reflector-controlled nuclear reactor. The fast reactor 1 includes a bottomed cylindrical reactor vessel 3, a shielding plug 4 for closing the top of the reactor vessel 3, a primary coolant 5 contained in the reactor vessel 3, and a reactor vessel 3. The core 7 immersed in the primary coolant 5, the reactor core 8 having a double cylinder surrounding the periphery of the reactor core 7, the reactor stop rod 9 configured to be freely inserted into and removed from the center of the reactor core 7, and the reactor core A reflector 11 arranged between the double cylinders of the tank 8 and moving in the longitudinal axis direction of the reactor vessel 3, and a neutron shield provided closer to the inner surface side of the reactor vessel 3 than the reactor core vessel 8 12 and a core support structure 15 that supports the core 7, the core tank 8, and the neutron shield 12.

  The reactor vessel 3 has a hemispherical bottom 3a at the lower end. The reactor vessel 3 includes an upper support 16 provided on the inner surface of the middle part of the cylindrical trunk 3b and a lower support 17 provided on the lower inner surface of the trunk 3b.

  The shielding plug 4 supports a reflector driving device 18 that moves the reflector 11 and a reactor stop rod driving device 19 that moves the reactor stop rod 9 on the top of the reactor vessel 3.

  The primary coolant 5 is liquid sodium.

  The core 7 includes a plurality of fuel assemblies 21 having nuclear fuel, and is configured in a cylindrical shape as a whole. The core 7 is supported by the core support structure 15 via an entrance module 22 formed below the core 7.

  The reactor core 8 includes a reactor core inner shell 24 that surrounds the reactor core 7, and a reactor core outer shell 25 that surrounds the reactor core inner shell 24. The reactor core inner cylinder 24 and the reactor core inner cylinder 24 are arranged concentrically, and form a cylindrical gap opened upward therebetween.

  The reactor stop rod 9 is held by a reactor stop rod drive device 19 so as to be movable in the direction of the center line of the trunk portion 3b of the reactor vessel 3 (that is, in the longitudinal axis direction of the reactor vessel 3). .

  The reflector 11 is disposed in a gap between the core tank inner shell 24 and the core core inner shell 24, and is configured in a sleeve shape (cylindrical shape or ring shape) as a whole. The reflector 11 is moved around the core 7 in the direction of the center line of the trunk portion 3b of the reactor vessel 3 (that is, in the longitudinal axis direction of the reactor vessel 3) by the reflector driving device 18, and the reactivity of the core 7 is increased. Control. The reflector 11 includes a solid neutron reflecting portion 11a and a hollow cavity portion 11b. The cavity portion 11b has a hollow portion in which an inert gas such as argon gas or a metal (for example, zirconium or hafnium) having a lower neutron reflection capability than the primary coolant 5 is enclosed.

  The neutron shield 12 is disposed between the core support structure 15 and the reactor vessel 3. The neutron shield 12 shields neutrons radiated from the core 7 through the reflector 11 or detoured. The fast reactor 1 includes an annular electromagnetic pump 27 accommodated in the reactor vessel 3 and installed above the neutron shield 12, and an intermediate electromagnetic pump 27 accommodated in the reactor vessel 3 and installed above the electromagnetic pump 27. And a heat exchanger 28. The electromagnetic pump 27 and the intermediate heat exchanger 28 are configured integrally or integrally, and are suspended and held in the reactor vessel 3 by a heat exchanger support structure 29 extending upward from the intermediate heat exchanger 28.

  The electromagnetic pump 27 is a fluid drive device that circulates the primary coolant 5 in the reactor vessel 3, and is configured in a ring shape substantially parallel to the inner surface of the reactor vessel 3.

  The intermediate heat exchanger 28 performs heat exchange between the primary coolant 5 and the secondary coolant 31. The secondary coolant 31 flows from the secondary coolant inlet nozzle 32 and reaches the intermediate heat exchanger 28. After the temperature is increased by exchanging heat with the primary coolant 5 in the intermediate heat exchanger 28, the secondary coolant 31 is cooled. It is sent from the material outlet nozzle 33 to a steam generator (not shown) outside the reactor vessel 3. The secondary coolant 31 is also liquid sodium like the primary coolant 5.

  FIG. 2 is a schematic longitudinal sectional view showing the in-core structure of the fast reactor according to the present invention.

  As shown in FIG. 2, the core support structure 15 of the fast reactor 1 is suspended from an annular upper support plate 35 fixed to the upper support base 16 of the reactor vessel 3 and an inner edge portion of the upper support plate 35. The support cylinder 36 and the lower end of the support cylinder 36 are brought into contact with the lower support 17 of the reactor vessel 3, and the reactor core 7 and the reactor core tank 8 (that is, the reactor core inner shell 24 and the reactor core outer shell). 25) and a circular lower support plate 37 that supports the neutron shield 12, and an intermediate support plate 38 that is formed to project from the outer surface of the support cylinder 36 into an annular shape. The upper support plate 35, the support cylinder 36, the lower support plate 37, and the intermediate support plate 38 are integrally formed. The core support structure 15 is configured using an austenitic steel material such as SUS304 or a ferritic steel material in consideration of radiation resistance and strength. Further, the core support structure 15 brings the lower support plate 37 into contact with the lower support base 17 during the steady operation of the fast reactor 1.

  The lower support plate 37 supports the core 7 through the entrance module 22 at substantially the center thereof, supports the core tank 8 around the core 7 and inside the support cylinder 36, and the neutron shield outside the support cylinder 36. 12 is supported. Further, the lower support plate 37 includes a large number of first flow path holes 37a penetrating the front and back in a region inside the support cylinder 36, and a large number of second flow passage holes 37b penetrating the front and back in a region outside the support cylinder 36. Have.

  Further, the lower support plate 37 has a hole 37 c in the outer peripheral edge overlapping the lower support 17. A spacer 41 fixed to the lower support 17 is loosely fitted in the hole 37c. The spacer 41 moves the end of the core support structure 15 on the side of the lower support base 17 while allowing the lower support plate 37 to move in the longitudinal axis direction and the radial direction of the reactor vessel 3 within the gap with the hole 37c. Are regulated appropriately. Note that the lower support plate 37 may be supported using a key structure instead of the spacer 41. If the difference in thermal expansion between the reactor vessel 3 and the support cylinder 36 can be reduced by reducing the axial length of the support cylinder 36 or selecting a material, the lower support plate 37 is fixed to the lower support base 17 with a fastening member such as a bolt. May be. In this case, a more robust core support structure can be obtained.

  Further, the lower support plate 37 has a flow hole 37 d that communicates with a gap between the core inner shell 24 and the core outer shell 25 of the core tank 8. The primary coolant 5 that flows into the core tank 8 from the flow hole 37 d cools the reflector 11.

  The upper support plate 35 places the outer peripheral edge on the upper support 16 of the reactor vessel 3 and supports the weight of the entire core support structure 15. That is, the core support structure 15 in which the upper support plate 35, the support cylinder 36, the lower support plate 37, and the intermediate support plate 38 are integrated is fixed to the upper support base 16 of the reactor vessel 3 by the upper support plate 35. . The upper support plate 35 is fixed to the upper support base 16 by a fastening member 42 such as a bolt. The upper support plate 35 holds the top of the columnar neutron shield 12 so as not to fall down.

  The upper support plate 35 inhibits expansion and contraction due to thermal expansion of the core tank outer shell 25 via a seal member 44 sandwiched between the inner periphery 35a and the core tank 8 (more specifically, the core tank outer shell 25). The radial direction of the core tank 8 is held so that it does not occur.

  The support cylinder 36 includes a heat shielding plate 45 on its inner periphery. The heat shielding plate 45 is configured in a thin multilayer structure and is disposed in a range of the height of the core 7 when viewed in the longitudinal axis direction of the reactor vessel 3 (region where the core 7 is present). The support cylinder 36 is protected from the generated heat.

  The intermediate support plate 38 has a hole 38a through which the neutron shield 12 is inserted. The intermediate support plate 38 is disposed outside the height range in which the core 7 exists when viewed in the longitudinal axis direction of the reactor vessel 3 (non-existence region of the core 7). Further, the intermediate support plate 38 supports the falling of the neutron shield 12 and functions as a strengthening wheel of the support cylinder 36.

  On the other hand, the fast reactor 1 includes an intermediate support base 48 that holds the neutron shield 47 in parallel with the intermediate support plate 38. The neutron shield 47 is shorter than the neutron shield 12.

  Further, the fast reactor 1 includes an upper partition wall 51 suspended from the inner shroud 28 a of the intermediate heat exchanger 28 to the vicinity of the upper support plate 35, and a manometer seal 52 provided between the upper partition wall 51 and the upper support plate 35. And a seal structure 53 for guiding discharge of the electromagnetic pump 27 to the neutron shield 12, and a manometer seal 52 and a cylindrical wall 54 disposed inside the seal structure 53 so as to protrude upward from the reactor core 8.

  Here, first, the electromagnetic pump 27 and the intermediate heat exchanger 28 are integrated by an intermediate header 58 that defines an intermediate plenum 57 that communicates the outlet of the intermediate heat exchanger 28 and the inlet of the electromagnetic pump 27. The intermediate header 58 has a through hole 58 a that guides the primary coolant 5 from the periphery of the electromagnetic pump 27 to the inlet side of the electromagnetic pump 27.

  The upper partition wall 51 is a cylindrical structure that is suspended and supported from the upper end portion of the inner shroud of the intermediate heat exchanger 28 and arranged on the inner side of the electromagnetic pump 27 and the intermediate heat exchanger 28. The upper partition 51 partitions the high temperature region of the primary coolant 5 inside the electromagnetic pump 27 and the intermediate heat exchanger 28, and the primary pump in which the electromagnetic pump 27 and the intermediate heat exchanger 28 are disposed between the reactor vessel 3. The flow path of the coolant 5 is partitioned.

  The high temperature region of the primary coolant 5 partitioned inside the electromagnetic pump 27 and the intermediate heat exchanger 28 is an upper plenum 61 where the primary coolant 5 warmed in the core 7 generates an upward flow. Further, the flow path of the primary coolant 5 in which the electromagnetic pump 27 and the intermediate heat exchanger 28 are disposed between the reactor vessel 3 passes the upper end of the upper partition wall 51 from the inside to the outside, and the intermediate heat exchanger 28. An annular descending flow path 62 that generates a descending flow in the order of the electromagnetic pump 27.

  The inner surface of the upper partition wall 51 is exposed to the high temperature region of the primary coolant 5, and the outer surface of the upper partition wall 51 is exposed to the primary coolant 5 before and after heat exchange by the intermediate heat exchanger 28. Since the upper partition wall 51 is exposed to an environment having such a severe temperature gradient, a heat shielding function capable of maintaining a temperature difference between the respective regions is necessary, and is configured in a thin plate multilayer structure. The upper partition 51 may have a structure in which a heat insulating material such as ceramic is disposed.

  The manometer seal 52 includes a double cylindrical plate 65 that forms a gap opened from the upper partition wall 51 toward the upper support plate 35, and a cylinder that protrudes from the upper support plate 35 and is inserted into the gap between the double cylindrical plates 65. And a wall 66. The manometer seal 52 is filled with an inert gas such as argon gas in the gap between the double cylindrical plates 65, and is balanced by the pressure difference between the upper plenum 61 and the periphery of the electromagnetic pump 27 to discharge from the electromagnetic pump 27 to the upper plenum 61. The amount of leakage between the sides is extremely small and almost zero. Moreover, this pressure difference is almost equal to the pressure loss inside the intermediate heat exchanger 28, and is at most about several kPa. Therefore, the difference in liquid level between the inert gas and the primary coolant 5 in the manometer seal 52 is only about several hundred mm. Furthermore, the inert gas filled in the manometer seal 52 also reduces the heat transfer from the upper plenum 61 that is the high temperature region to the annular downflow passage 62 that is the low temperature region.

  The seal structure 53 communicates with a header 68 provided on the discharge side of the electromagnetic pump 27, a nozzle 69 protruding from the header 68 toward the upper support plate 35, and a flow passage hole 35 b penetrating the upper support plate 35. A nozzle receiver 71 (nozzle receiver) that guides the primary coolant 5 discharged from 69 to a flow path between the upper support plate 35 and the lower support plate 37, and a slidable movement between the nozzle 69 and the nozzle receiver 71. And a seal ring 72 for sealing. The header 68 defines an annular channel that covers the outlet of the electromagnetic pump 27. A plurality of nozzles 69 are provided along the ring-shaped header 68. The seal ring 72 may be double or more.

  The seal structure 53 absorbs a difference in thermal expansion between the electromagnetic pump 27 and the intermediate heat exchanger 28 and the core support structure 15 by the nozzle 69 slidably inserted into the nozzle receiver 71, from the electromagnetic pump 27. The discharged primary coolant 5 is efficiently made into a circulation flow of the reactor vessel 3. Even if the primary coolant 5 discharged from the electromagnetic pump 27 leaks to the periphery of the electromagnetic pump 27, it is sucked into the electromagnetic pump 27 again from the through-hole 58 a of the intermediate header 58 to generate a circulating flow. A flow meter can be installed between the electromagnetic pump 27 and the header 68.

  The cylindrical wall 54 is a heat shielding plate that protects the manometer seal 52 and the seal structure 53 from high heat in a high temperature region.

  The fast reactor 1 configured in this manner first heats the primary coolant 5 in the core 7. The heated primary coolant 5 moves up the upper plenum 61 and flows into the intermediate heat exchanger 28 over the top of the upper partition wall 51. The primary coolant 5 that has flowed into the intermediate heat exchanger 28 is cooled by exchanging heat with the secondary coolant 31, passes through the intermediate header 58, and is sucked into the electromagnetic pump 27. The electromagnetic pump 27 discharges the sucked primary coolant 5 toward the upper support plate 35 of the core support structure 15. The primary coolant 5 discharged from the electromagnetic pump 27 passes through the seal hole 53b of the upper support plate 35 and the seal structure 53 and descends while cooling the neutron shield 12, and lower support plate of the core support structure 15 37 and reaches the lower plenum 73 at the bottom of the reactor vessel 3. The primary coolant 5 that has reached the lower plenum 73 is reversed and becomes an upward flow, passes through the first flow path hole 37 a of the lower support plate 37, passes through the entrance module 22, and flows into the core 7 again. The flow of the primary coolant 5 is indicated by solid arrows in FIG.

  In the fast reactor 1 according to the present embodiment configured as described above, the integrally formed core support structure 15 is suspended by the reactor vessel 3 (more specifically, the upper support 16 of the reactor vessel 3). By providing the structure to support, the core 7, the entrance module 22, the core tank 8, and the neutron shield 12 can be taken out integrally, and the installation property can be greatly improved.

  In addition, the fast reactor 1 according to the present embodiment is configured such that the lower support plate 37 of the core support structure 15 is not fixed to the lower support base 17 and is movable in the longitudinal axis direction and the radial direction of the reactor vessel 3. Thus, it is possible to support the reactor vessel 3 and the core support structure 15 while allowing a difference in thermal expansion and displacement during an earthquake.

  Furthermore, the fast reactor 1 according to the present embodiment prevents the neutron shield 12 from collapsing while improving the strength against buckling and differential pressure as a strong wheel of the support cylinder 36 by the intermediate support plate 38 of the core support structure 15. be able to. The intermediate support plate 38 is disposed in a non-existing region of the core 7 and can avoid deterioration of structural integrity due to irradiation embrittlement in the central portion of the core 7 where radiation irradiation conditions are severe.

  Furthermore, the fast reactor 1 according to the present embodiment includes the heat shielding plate 45 inside the support cylinder 36, and suppresses the temperature difference between the inside and the outside of the support cylinder 36 to reduce the thermal stress and support the core. The structural integrity of the structure 15 is maintained. Moreover, the temperature gradient around the reflector 11 is also relaxed by the heat shielding plate 45, and the thermal stress generated in the reflector 11 can be reduced.

  In addition, the fast reactor 1 according to the present embodiment can substantially reduce the amount of leakage between the high temperature region and the low temperature region in the primary coolant 5 discharged from the electromagnetic pump 27 by the manometer seal 52, and the heat exchange performance is deteriorated. It is possible to avoid a decrease in reactor performance due to. In addition, heat transfer can be reduced by providing the cylindrical wall 54 inside the manometer seal 52.

  Furthermore, the fast reactor 1 according to the present embodiment can minimize the amount of leakage in the primary coolant 5 discharged from the electromagnetic pump 27 by the seal structure 53, and can reduce the influence on the reactor performance.

  Furthermore, the fast reactor 1 according to the present embodiment includes the backup support structure 74 and can maintain the soundness of the core 7 even when the core support structure 15 is broken.

  Therefore, the in-furnace structure of the fast reactor 1 according to the present embodiment is excellent in functionality, installation, and structural soundness, and reliability is improved.

DESCRIPTION OF SYMBOLS 1 Fast reactor 3 Reactor vessel 3a Bottom part 3b Trunk part 4 Shielding plug 5 Primary coolant 7 Core 8 Reactor core 9 Reactor stop rod 11 Reflector 11a Neutron reflector 11b Cavity part 12 Neutron shield 15 Core support structure 16 Upper support Base 17 Lower support base 18 Reflector drive unit 19 Furnace stop rod drive unit 21 Fuel assembly 22 Entrance module 24 Core tank inner shell 25 Core tank outer shell 27 Electromagnetic pump 28 Intermediate heat exchanger 28a Inner shroud 29 Heat exchanger support structure 31 Secondary coolant 32 Secondary coolant inlet nozzle 33 Secondary coolant outlet nozzle 35 Upper support plate 35a Inner circumference 35b Channel hole 36 Support cylinder 37 Lower support plate 37a First channel hole 37b Second channel hole 37c Hole Portion 37d Flow hole 38 Intermediate support plate 38a Hole 41 Spacer 42 Fastening member 44 Seal member 45 Heat shield plate 47 Neutron shield 8 Intermediate support base 51 Upper partition wall 52 Manometer seal 53 Seal structure 54 Cylindrical wall 57 Intermediate plenum 58 Intermediate header 58a Through port 61 Upper plenum 62 Annular downflow passage 65 Double cylindrical plate 66 Cylindrical wall 68 Header 69 Nozzle 71 Nozzle receiver 72 Seal Ring 73 Lower plenum 74 Backup support structure

Claims (8)

A bottomed cylindrical reactor vessel;
An upper support provided on the inner surface of the middle part of the trunk of the reactor vessel;
A lower support provided on the lower inner surface of the trunk of the reactor vessel;
A coolant contained in the reactor vessel;
A core housed in the reactor vessel and immersed in the coolant;
A core of the reactor core surrounding the reactor core;
A core outer shell surrounding the core inner shell,
A reflector disposed between the inner core of the reactor core and the outer shell of the reactor core and moving in the longitudinal axis direction of the reactor vessel;
A neutron shield provided closer to the inner surface side of the reactor vessel than the reactor core outer shell,
An annular upper support plate fixed to the upper support, a support cylinder suspended from the inner edge of the upper support, and a lower end of the support cylinder, abutting against the lower support and A reactor core, a core support structure in which a circular lower support plate for supporting the reactor core inner shell, the reactor core outer shell, and the neutron shield is integrally formed. Furnace structure. The said core support structure was provided with the intermediate | middle support plate which has the hole by which the said neutron shield was penetrated integrally formed by making it project from the outer surface of the said support cylinder in the ring shape. In-core structure of the fast reactor. The in-core structure of a fast reactor according to claim 2, wherein the intermediate support plate is disposed in a non-existing region of the core as viewed in the longitudinal axis direction of the reactor vessel. A spacer is provided that is loosely fitted in a hole formed in the lower support plate and fixed to the lower support base, and appropriately restricts the movement of the lower support plate side end of the core support structure. Item 4. The internal structure of the fast reactor according to any one of Items 1 to 3. The in-furnace structure of a fast reactor according to any one of claims 1 to 4, further comprising a heat shielding plate disposed inside a support cylinder of the core support structure and having a thin multi-layer structure. An intermediate heat exchanger disposed above the upper support plate;
An upper partition wall suspended from the inner shroud of the intermediate heat exchanger to the vicinity of the upper support plate;
A double cylindrical portion that forms a gap opened from the upper partition toward the upper support plate, and a manometer seal that has a cylindrical wall that protrudes from the upper support plate and is inserted into the gap of the double cylindrical portion. The in-furnace structure of a fast reactor according to any one of claims 1 to 5, further comprising: A fluid drive device arranged above the upper support plate to flow a coolant in the direction of the upper support plate;
A header provided on the discharge side of the fluid drive device;
A nozzle protruding from the header toward the upper support plate,
A nozzle receiver that communicates with a hole penetrating the upper support plate and guides a coolant discharged from the nozzle to a flow path between the upper support plate and the lower support plate;
The in-furnace structure of a fast reactor according to any one of claims 1 to 6, further comprising a seal ring that slidably seals between the nozzle and the nozzle receiver. The fast reactor interior according to any one of claims 1 to 7, further comprising a backup support structure provided to be biased toward the bottom side of the reactor vessel with respect to the lower support plate. Construction.

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