JPH0815468A - Integrated-type fast neutron reactor from which internal structural element can be removed - Google Patents

Abstract

PURPOSE: To increase the speed of the construction work and the disassembly work by simply supporting a main vessel in which a core immersed in the liquid metal for cooling is stored, a primary circulation pump, an intermediate heat exchanger, and internal structural elements fitted to the inside of the main vessel in a removable or hoistable manner to facilitate the access to the inside. CONSTITUTION: A core 11, a primary pump 5, an intermediate heat exchanger 6, and internal structural assemblies 12-16, 22 are immersed in a main vessel 1 in which the liquid metal for cooling is filled to the level 3, and an upper part is covered with a horizontal slab 4. The pump 5 and the heat exchanger 6 are fitted to the inside of the main vessel 1 through an opening part of the slab 4, so as to be hoisted from and taken out of the main vessel 1. The slab 4 itself is also hoisted and separated from the main vessel 1. A girder 12 to an upper part of which the core 11 is fitted is supported on an upper surface of a bottom plate 13, and a collection device 15 is fitted to an inner supporting part of a supporting plate 14 and fitted to a bottom part of the main vessel 1. The internal structural elements 12-16, 22 are not mechanically fixed, but fixed to the inside of the main vessel 1 with the self-weight and a supporting mechanism.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an integrated fast neutron reactor having a main reactor vessel in which internal structural elements can be removed.

[0002]

2. Description of the Related Art An integrated fast neutron reactor is provided with a main reactor vessel for containing the coolant of the reactor. Generally, the coolant of the reactor is a liquid metal such as sodium, A reactor core, a coolant circulation pump, and an intermediate heat exchanger that transfers the heat of the reactor coolant to the secondary coolant are submerged therein.

The pump submerged in the coolant inside the container, that is, the primary pump, circulates the liquid metal constituting the coolant, passes through the core, and contacts the fuel assembly to heat it. The heated liquid metal then enters the intermediate heat exchanger where it contacts and cools the secondary coolant. The secondary coolant is also typically liquid metal. Upon exiting the intermediate heat exchanger, the cooled liquid metal is recovered by the primary pump.

The main vessel of a nuclear reactor is, among other things, part of the core cooling liquid metal used for compartmentalization of the internal volume of the main vessel of the reactor, support of the core and cooling of the inner surface of the main vessel of the reactor. It contains the internal structure responsible for the induction of. The internal structure of the main vessel of the reactor comprises, inter alia, an inner vessel, which in the main vessel of the reactor is the heated liquid metal emerging from the first area, ie the core of the reactor. To form a second area, i.e., a cold tank for receiving cooled coolant exiting the intermediate heat exchanger.

The intermediate heat exchanger and pump are tall components of generally cylindrical shape, both vertically submerged within the reactor vessel. The upper part of the reactor vessel is closed with a slab and is provided with openings for the upper components of the pump and the heat exchanger to pass through.

[0006] The intermediate heat exchanger has an opening penetrating the inner vessel and in communication with a hot tank for containing heated liquid metal, and an exit for cooling liquid metal in communication with a cold tank. Is equipped with. The suction side of the primary pump is connected to the cold tank.

A fast neutron reactor is generally equipped with an assembly of a primary pump and an intermediate heat exchanger, which assembly is within an annular area whose axis of symmetry is the longitudinal axis of symmetry of the main vessel. , Through a lateral closed slab at the top of the main reactor vessel.

The core of a nuclear reactor is supported by a part of an internal structure called a girder, and the internal structure itself is attached to an internal structural element called a floor plate. The floor plate is supported by a part of the inner surface of the main vessel of the nuclear reactor and the bottom of the vessel. Part of the internal structure is
The inner surface of the container separates the annular space, and in the periphery of the container,
It constitutes a circulating space for the liquid metal for cooling the container.

Regarding the internal structure of the main vessel of the nuclear reactor, it is also possible to provide a recovery device on the upper part of the core to protect the bottom of the vessel and recover the waste material generated from the core of the nuclear reactor. In prior art nuclear reactors, the internal structure is located inside the main vessel to form the reactor block, which is typically a solid welded assembly.

Regarding the method of realizing the internal structure of such a fast neutron reactor, the French patent FR-A-
2,506,062, FR-A-2,680,597,
FR-A-2,558,635, FR-A-2,54
1,496.

In particular, some of the large components of these fast neutron reactors, such as the primary pump, the intermediate heat exchanger, the core, which make up the passages of the instrumentation equipment of the core and the pipes of liquid metal in the upper part of the vessel. The plug-cover and the like are detachable parts, and can be lifted out of the container and taken out by using dedicated equipment.

However, internal component elements within the main vessel may pass through the opening of the closed slab of the main vessel because they are welded together during assembly of the reactor block at the site or due to their large size. No, it cannot be removed. In fact, the slab is generally structured so that it cannot be lifted from the main container and opened, so that the elements within the container can only be removed through the openings in the slab.

According to the conventional method, the slab can be of a hybrid structure in which metal parts are embedded in the concrete that is constructed during the construction of the reactor building.
The metal elements embedded in the concrete are left in place for the welding of the upper part of the reactor vessel. The main container is
It can also be suspended on a flange incorporated into the structure of the reactor building, in which case the slab will be attached to a part of the reactor building.

[0014]

In the case of nuclear reactors according to existing techniques, it is not possible to disassemble or replace internal structural elements, because the interior of the vessel is inaccessible. Similarly, it is not possible to remove or install internal structural elements from the reactor slab.
When it is necessary to take out the internal structure, that is, when the life of the reactor is reached and the dismantling work is performed, sodium in the reactor vessel is completely discharged, and the reactor is kept in an inert gas atmosphere. The internal structure must be cut.

Therefore, it is impossible to disassemble the internal structure to repair or replace it.
It is also not possible to lift the entire internal structure from inside the container to access the bottom of the container or to inspect or repair the bottom of the main container.

Furthermore, since the internal structure has to be welded to the inside of the main vessel, the assembly and fixing work of the internal structure constitutes a considerable part of the construction period of the reactor structure. Finally, because of the way the internal structure is implemented,
The size and weight of the internal equipment are also extremely important factors.

[0017]

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to propose an integrated fast neutron reactor having the following structure.

The components of the integrated fast neutron reactor of the present invention include a main container in which a reactor core submerged in a cooling liquid metal is enclosed, and at least one unit for circulating a coolant in the container. A core consisting of a primary circulation pump, at least one intermediate heat exchanger submerged in the cooling liquid metal, and a large metal element located inside the main vessel and mounted inside the main vessel. An internal structure with at least one inner vessel forming an area for receiving the heated liquid metal leaving the intermediate heat exchanger and an area for receiving the cooled liquid metal exiting the intermediate heat exchanger, and for cooling in contact with the inner wall of the main vessel A plate that constitutes a liquid metal flow conduit,
It consists of core support elements. The internal structure of the reactor is realized so that it can be removed or lifted from the inside of the main vessel. This makes construction work easier and faster.

According to this object, each internal structural element is maintained in a corresponding mechanism of at least one component of the assembly consisting of the main container and the internal structural element for fixing by means of a simple support inside the main container. And a support mechanism.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to understand the present invention more accurately, a method for realizing a fast neutron reactor according to the present invention will be described below with reference to the accompanying drawings. The embodiments described below are merely examples, and the present invention is not limited thereto.

FIG. 1 is a front vertical sectional view of a vessel and internal structure of a fast neutron reactor according to the present invention. FIG. 2 is a longitudinal sectional view of a part of the internal structure near the lower end of the main container and the pump. FIG. 3 is a longitudinal sectional view of a part of the internal structure near the lower end of the main container and the intermediate heat exchanger. 4 and 5 are longitudinal cross-sections of two parts of the internal structure, showing the sodium conduit for cooling the main container. 6 is an arrow 5-5 of FIG.
It is sectional drawing by. FIG. 7 is a diagram indicated by arrow 6 in FIG. FIG. 8 is a vertical cross-sectional view of a part of the internal structure of the nuclear reactor that supports the core. FIG. 9 is an enlarged view showing details of FIG. FIG. 10 is a diagram indicated by an arrow 9 in FIG. Figure 11
[Fig. 3] is a vertical cross-sectional half view of a part of the internal structure forming the liquid metal pipe for cooling the main container. FIG. 12 shows the arrow 1 in FIG.
It is sectional drawing by 1-11. FIG. 13 is a top view of a closed slab of a reactor vessel. FIG. 14 is a partial cross-sectional view of the periphery of a closed slab of a reactor vessel. FIG.
FIG. 4 is a top view of a portion of a closed slab of a nuclear reactor. FIG.
FIG. 16 is a partial vertical sectional view taken along the arrow 15-15 in FIG. 15. Figure 17 is a cross-sectional view of the reactor main vessel and internal structure.
The decomposition order of internal structural elements is shown.

In FIG. 1, there is shown a reactor main vessel 1 containing cooling liquid metal up to the level of reference numeral 3 and mounted inside a reactor building structure 2. The reactor core, internal assembly, primary pump and intermediate heat exchanger are submerged.

The main container 1 is surrounded by a safety container 1 ',
The space around the main container 1 is filled with gas. The main vessel 1 is closed by a fairly thick horizontal slab 4, which is located above the upper end of the vessel 1 in the reactor structure 2
Attached to.

The slab 4 is provided with an opening,
The upper pump 5 and the intermediate heat exchanger 6 are configured to pass therethrough. As can be seen from FIGS. 13 and 15, the reactor includes three primary pumps 5.
These primary pumps 5 are arranged at an angle of 120 ° with respect to the axis of the main container, and six intermediate heat exchangers 6 are arranged between the respective primary pumps 5. .

The assembly of the primary pump 5 and the intermediate heat exchanger 6 passes through the slab 4 of the nuclear reactor in an annular area centered on the vertical axis of the main vessel. The interior space of the container 1 between the upper level 3 filled with liquid metal made of liquid sodium and the lower surface of the closed slab 4 is filled with an inert gas made of argon.

An orifice is provided at the center of the slab 4, and a rotary plug 8 equipped with a reactor fuel charging machine 9 is mounted therein. An assembly 10, which is called a core plug-cover, is arranged on an upper portion of a core 11 of a nuclear reactor, and is provided with measuring instruments for performing measurement in the core. At the outlet of the core 11, a bypass mechanism for liquid sodium circulating in the container is provided.

The core 11 is composed of a fuel assembly, and its lower part, that is, the legs are attached to a mechanically welded structure 12 called a girder, which constitutes a part of the internal structure of the reactor vessel 1. are doing. The girder 12 is supported by a mechanically welded structure 13 called a floorboard,
The floor plate itself is attached to the bottom of the main container 1 and to the top of the support plate 14. The support plate 14 is provided with an internal structural element 15 called a recovery device on its inner surface. The recovery device is attached to the lower part of the floor plate, and is capable of recovering the waste material of the core in the event of an accident or treatment of the fuel assembly.

The internal structural element 16, called the inner container,
A cylinder attached to the top of the floor plate and coaxial with the vessel 7 about the reactor core 11, an annular flat step 16a, and an upper outer cylinder having a diameter slightly smaller than the inner diameter of the main vessel 1. 16b and.

The inner cylindrical body 16c of the inner container 16 is fixed along the inner circumference of the flat step 16a, and the upper outer cylindrical body 16b.
Are fixed along the outer circumference of the flat step 16a. The flat step 16a is provided with a plurality of openings, and each opening has a cylindrical body 17 penetrating the primary pump 5.
Alternatively, the cylindrical body 18 penetrating the intermediate heat exchanger 6 is fixed.

The upper part of the cylindrical body 17 penetrating the primary pump 5 is located above the upper level 3 of the liquid sodium in the container 1. However, the cylindrical body 18 penetrating the intermediate heat exchanger 6
Since the upper part of is located inside the liquid sodium,
An inert acid separation mechanism 18a is provided which cooperates with the corresponding mechanism of the intermediate heat exchanger 6 to ensure the hermeticity of the intermediate heat exchanger 6 in the inner vessel.

As described above, in the inner container, the internal volume of the main container is the first space 19 called the hot tank above the core.
a and a second space 19b called a cold tank below the core. The liquid sodium circulates in the container by the primary pump 5, passes vertically through the core from the bottom to the top (arrow 20), is heated in contact with the core assembly 11, and is heated in the hot tank 19 a above the core. Get in The liquid level of liquid sodium in the hot tank 19a of the main container 1 is a dynamic liquid level and comes close to the upper level indicated by reference numeral 3.

Each intermediate heat exchanger 6 has a hot tank 19a.
The upper opening 6a connected to the cold tank 19b and the lower opening 6b connected to the cold tank 19b. The heated sodium discharged from the core has an upper opening 6a in each intermediate heat exchanger.
And then circulates in the intermediate heat exchanger, is cooled by contact with the secondary sodium, has a lower temperature than when it entered the upper opening, and exits from the opening 6b to the cold tank 19b. The secondary sodium heated in contact with the primary sodium is used to generate steam in a steam generator located outside the reactor vessel.

Since the suction portion arranged at the lower end side of the primary pump 5 is positioned in the cold tank 19b, it sucks the cooled sodium discharged from the lower opening portion 6b of the intermediate heat exchanger to form the floor plate 13 and Cooled sodium is fed into the core through the girder 12. The liquid level of the liquid sodium 21 in the cold tank is arranged above the liquid level 3 in the hot tank.

A portion of the cooled sodium is part of the floorboard 13.
Leaks from the inner side of the inner wall of the main vessel 1 and flows into the annular space composed of the inner surface of the main vessel 1 and the cooling liquid metal guide cylinder 22 forming a part of the internal structure of the reactor. The upper part of the guide cylinder 22 constitutes a drainage port for returning the cooling sodium from the inner surface of the main container 1 to the area of the cold tank positioned outside the cylinder 16b of the inner container.

According to a general feature of the invention, each internal structural element 12, 13, 15, 16, 22 of the nuclear reactor is a corresponding mechanism of another internal structural element or the inner vessel 1.
And a maintenance and support mechanism attached to a portion of the inner surface of the. The internal structural elements therefore need not be fixed by welding or mechanical fixing methods such as screws or bolts,
It is securely fixed inside the main container by its own weight and maintenance and support mechanism.

The primary pump 5 and the intermediate heat exchanger 6 are usually mounted inside the container via the opening of the slab 4 so that the primary pump 5 and the intermediate heat exchanger 6 can be lifted out of the main container 1. Since the slab 4 is realized so that it can be lifted from the structure of the nuclear reactor and separated from it, as will be described later, the elements of the internal structure of the main container 1 can be sequentially taken out, as described later.

The girder 12, to which the reactor core 11 is attached, is supported on the top surface of the floor plate 13. The recovery device 15 is attached to the support portion inside the support plate 14, and is further attached to the bottom portion of the main container 1 via this. The inner container 16 includes a floor plate 13 centered on the girder 12 and the core 11 via a lower portion of the inner cylindrical body 16c.
Is attached to the upper surface of.

The lower portion of the cooling sodium guiding cylinder 22 is attached to the support portion of the floor plate on the inner surface of the main container 1. The side wall of the main container 1 is a cylindrical shape, the bottom is an extremely flat bowl-shaped end plate, and the center of the bottom has a spherical shape with an extremely large curvature. The peripheral portion is joined to the side wall of the main container and the central portion of the spherical container bottom, and has a circular ring-shaped longitudinal section. In general, the height to diameter ratio of the main vessel 1 is significantly higher than that of existing reactor main vessels.

FIG. 2 shows the lower part of the container 1, in which the lower part of the primary pump 5 is arranged below the inner container 16 inside the cold tank 19b. The floor plate 13 is realized as a mechanical welding structure, and includes upper and lower plates in the horizontal direction, outer side walls welded to the upper and lower plates, and reinforcing and fixing bars for the upper and lower plates. In the floor plate, three aggregates 23 are fixed to the outer side wall, each of which corresponds to the opening position of the side wall.

Each assembly 23 is provided with a casing 24 in which the lower part of the primary pump 5 is incorporated, and a girder 12 and a sodium induction pipe 25 to the core 11 supported by the girder 12. The casing 24 and the pipe 25 are welded to a joint material welded to the inside of the opening provided in the wall of the floor plate.

The pipe 25 has one end connected to this connecting material,
The other end is welded to another tie joined to the top plate of the floor plate 13 to form a hermetically connecting element up to the girder 12. The steel plate 25a is fixed around the convex outer surface of the sodium supply pipe 25. This steel plate 2
5a plays a role of supporting the pipe when the pipe is broken.

At the lower part of the side wall of the floor plate 13, a conical plate 26 is coaxially arranged with respect to the floor plate 13 and surrounds the peripheral portion of the floor plate. The conical plate 26 is provided at its end with a support crown 27 through which the sole plate 13 is supported by a machined toroidal support heel 28 on top of the shim in the container 1. It has become. The sodium guiding cylinder 22 for cooling has a floor plate 13
It is supported by a support heel 28 of the container via a support crown 27 of the.

An opening is provided in the conical plate 26 of the floor plate 13, and the casing 24 of the primary pump 5 is provided therein.
A short plate for passage of is fixed. Floor board 1
The lower plate of 3 is arranged somewhat above the support plate 14 which is connected to the bottom of the container 1, when the floor plate is seated on the support surface 28 of the main container 1 via the support crown 27.
The plate 14 is adapted to maintain and fix the floor plate when the support mechanism of the floor plate is broken due to an accident.

The device 15 for collecting waste material from the core comprises a deflector and a waste material spreading mechanism, and is attached to the machined support surface 14a above the shim inside the plate 14. It should be noted that the floor plate 13 and the recovery device 15 can be freely attached to the respective support mechanisms 28 and 14a without being welded to the container or the support plate 14 or mechanically coupled.

FIG. 3 shows the lower part of the main reactor vessel 1 in which the plate and the hermetically-penetrating penetrations 18, 18a are located.
, The intermediate heat exchanger 6 passing through the inner container 16 is arranged, and the upper opening 6a and the lower opening 6b of the intermediate heat exchanger are arranged on both sides of the flat step 16a of the inner container 16. Has been done. The flat step 16a is the inner cylinder 1 of the inner container.
Although 6c and the outer cylindrical body 16b are connected, this step may be a step of another shape, for example, a conical step.

In general, preferentially flat tiers may be used for small and medium capacity nuclear reactors, and conical tiers may be used for large capacity nuclear reactors. Protective screen 6
c is fixed to the support mechanism 26 of the floor plate 13 facing the outlet opening 6b of the intermediate heat exchanger 6. The cooling liquid sodium recovery pipe 30 is attached to the upper portion of the floor plate support plate 26 at a position inclined with respect to the horizontal direction.

As shown in FIGS. 4 and 5, the liquid sodium pipe 30 is inserted between the reactor pump and the intermediate heat exchanger in a direction parallel to the support plate 26 of the floor plate. ing. Then, one end thereof is welded to the pipe welded to the side wall of the floor plate 13, and the other end is frictionally attached to the opening of the support crown 27 of the forged and machined crown-shaped floor plate. Has been done.

The support member 28 of the main container 1 at the position of the liquid sodium pipe 30 is forged and machined,
As shown in FIGS. 4 and 6, a depression 32 is partially processed. As a result, the end of the pipe 30 is connected to the container 1
To the annular space 33 constituted by the inner surface of the plate and the outer surface of the sodium guide tube 22 for cooling. Due to such a structure, the cooled sodium leak circulates in the lower part of the core 11, is guided by the pipe 30, and enters the annular space 33, in which sodium flows from the bottom to the top. To cool the plate of the main vessel.

The surfaces supported by or in frictional contact with the pipe 30, the supporting crown 27, the parts 28 of the main container and the ring 22a of the guide cylinder for the cooling liquid metal reduce friction and suppress wear. Aluminized or coated with aluminized plate.
Aluminum treatment of the friction surface is preferred over alloy coatings such as cobalt containing stellite. As is well known, bringing cobalt into the reactor vessel should be avoided as much as possible.

As shown in FIG. 7, the parts 27 and 28 supporting each other are embossed at an angle of 120 ° about the central axis of the container.
ent). These mortise grooves face each other when a floorboard is installed in the container.

After mounting the floorboard in the container, the key 34 is inserted into each cavity formed by the two opposing groove grooves. In this way the floor plate is prevented from rotating relative to the inner surface of the container. The cylindrical body 22 is also fixed to the wall body of the main container 1 so as not to rotate.

As shown in FIGS. 8 and 9, the girder 12 is attached to the upper plate of the floor plate 13 via the lower part of the side wall which constitutes the support base of the girder. Further, the central pivot 12a (FIG. 1) is the floorboard 1
3 is attached to a member fixed to the upper plate. The key is fixed so that the girder 12 does not rotate with respect to the floor plate 13.

The three sodium supply pipes of the core are respectively connected to the primary pump 5, and the opposite side of the pump 5 is provided with a pipe port 35 attached to the opening of the girder 12 provided with the forging passage ring. It is linked to the forgings that make it up. Each ring passing through the lower wall of the girder 12 is provided with a ring-shaped waterproof component 37, and the pipe port 3 is provided inside thereof.
5 is attached.

The joint 38 made of a metal ring is inserted between the inner upper shoulder of the annular waterproof component 37 and the ring passing through the opening of the girder 12. The joint 38 is compressed between the waterproof part 37 and the girder by the pressure of the liquid metal. The snap ring-shaped joint 39 is inserted between the outer surface of the pipe port 35 and the cylindrical inner surface of the waterproof component 37. When the liquid pressure is applied to the joint 39, the joint can be pressed against the outer surface of the pipe port 35 to ensure the waterproof connection between the pipe of the pump and the girder.

In this way, the pipe port 35 can move laterally with respect to the girder 12 when heat is transferred to the inside of the reactor vessel. Similarly, the piping port 35 can be moved vertically inside the waterproof component 37.

The sodium is guided in a leak-free manner and passes between the pump tubing and the inner space of the girder, as illustrated by arrow 40. Liquid sodium flows through the openings 41 in the upper plate of the girder 12.
And enters the reactor core 11 of the nuclear reactor above the girder 12.

The inner cylinder 16c of the inner container 16 is connected to a ring 36 whose lower portion is forged and machined. Since this ring has shoulders, when the inner container 16 is mounted in the main container 1, the ring is shaped so as to cover the upper part of the side wall of the floor plate 13. When the upper part of the side wall of the floorboard 13 is incorporated into the component 36 of the inner vessel, the inner vessel is fixed to the floorboard 13.
And the floor plate itself is also perfectly positioned centrally in the container via the forged support ring 27. Similarly, by incorporating the upper portion of the floor plate 13 into the component 36, the inner container can be fixed in the main container so as not to swing with respect to the floor plate 13.

In FIG. 10, the supporting forged part 36 is provided with a mortise groove 36a, and when the inner container is installed in the main container, the mortar groove 36a faces the corresponding mortise groove formed on the upper side wall of the floor plate 13. . To reinforce the fixation of the inner container in the main container, a key 42 is inserted in each cavity defined by the facing tenon of the support part 36 and the floor plate 13. In this way, the inner container is prevented from rotating with respect to the base plate, and the base plate itself is also prevented from rotating with respect to the main container via the key 34 shown in FIGS. 4 and 7.

All surfaces of the girder 12, floor plate and support component 36 are adapted to support one another. In this case, since the surfaces are made of stainless steel, when the internal structural elements support each other, they are brought into contact through aluminized parts so that the stainless steels do not come into direct contact.

As can be seen from FIG. 11, the upper portion of the sodium guiding cylinder 22 for cooling is connected to the upper portion of
It is connected to the two cylinders 43 and 44 and constitutes a discharge port for liquid sodium flowing from the pipe 30 in the annular space 33 between the main container 1 and the cylinder 22. The liquid sodium passes through the upper part of the upper end of the cylinder 43, and this upper part is
It is an inlet that flows into the outlet between 3 and 44.

The liquid metal dump 45 shown in FIGS. 11 and 12 is capable of feeding the liquid metal back to the cold tank where the liquid sodium level 21 is significantly lower than the liquid sodium level 3 in the hot tank. The cooling liquid sodium thus circulates in contact with the inner wall of the main vessel, cooling the main vessel and returning to the cold tank without vibrating the reactor structure.

FIG. 13 shows a closed slab 4 of a reactor vessel.
Is shown, and the closed slab is provided with an opening so that the primary pump 5 and the intermediate heat exchanger 6 can pass therethrough. The slab 4 also has an opening in the center, in which a large rotating plug 8 of the nuclear reactor is attached so that it can rotate on the slab 4 about the vertical axis 7 of the vessel. Has become.

A small rotary plug 46 is rotatably attached to the large rotary plug 8 about a vertical axis different from the central axis of the container 7. The small rotary plug is provided with a fuel charger 9 for a nuclear reactor. Fixed. By combining the rotation of the large rotary plug 8 and the rotation of the small rotary plug 46, the fuel exchanger can be aligned and installed in the vertical direction of any fuel assembly in the reactor core 11. The large rotating plug 8 also has a core plug-cover 10 at the center.

FIG. 14 shows a part of the outer circumference of the slab 4 of the nuclear reactor, and the outer circumference is provided with a mechanism for supporting and fixing the slab to the fixed structure 2 of the nuclear reactor. The upper part of the cylindrical body of the main container 1 is connected to the annular flange 47. Similarly, the other flange 48 also has an annular shape, and is fixed to the upper portion of the structure 2 of the reactor centering on the cavity forming the container pit in which the main container 1 is arranged. The flange 48 is fixed to the structure of the nuclear reactor and is provided with an annular recess so that the flange 47 connected to the upper part of the cylinder of the main vessel 1 can be attached.

The slab 4 consists of a very thick steel plate, the outer side of which is the flange 4 of the container.
7 and its supporting and fixing mechanism are machined so that it can be housed. The slab 4 is provided with a shoulder portion 4a forming a ring-shaped surface downward, and a support mechanism 49 is fixed on the ring-shaped surface, and is fixed to the upper surface of the flange 47 of the main container 1. It is shaped to face the corresponding support mechanism 49 '.

The support mechanisms 49, 49 'have curved support surfaces aligned according to a common vertical direction 51.
A support mechanism 52 is inserted between the pair of support mechanisms 49, 49 'of the slab, and is mounted so as to slide inside the support surfaces of the mechanisms 49, 49' and rotate.

In this way, the peripheral portion of the slab moves, and for example, radial expansion can be absorbed. Similarly, the rotation support mechanism can absorb the deformation due to the bending of the slab. The support mechanism 52 that slides and rotates is arranged on the periphery of the slab.

Between the two continuous support mechanisms 52, a pop-out prevention fixing tool 53 for the slab 4 is inserted. Each pop-out prevention mechanism 53 includes a tie beam 54, and the tie beam is attached to the through hole in the peripheral portion of the slab 4 and the through hole of the flange 47 of the container located on the axial extension thereof.

The tie beam is arranged in the through hole of the flange 47 of the container, passes through the hole of the flange 48, and is fixed in a state of being embedded in the structure 2 of the nuclear reactor by the nut 55.
It is screwed to. A waterproof closing cover 56 is attached to an upper portion of the head 54a of the tie beam 54 so that the space around the tie beam 54 can be closed while fixing the tie beam while maintaining the hermeticity.

The flange 47 is fixed inside the recess of the flange 48 by welding 57. The waterproof plate 50 is welded to the inner periphery of the upper portion of the flange 47 by welding 62.
Has been fixed. This plate can be connected by welding 61 on the opposite side of the welding 62 to a part of the outer circumference of the slab 4.

By thus closing the inner space of the main container 1 while maintaining the hermeticity, an inert gas such as argon can be contained above the liquid level of the liquid sodium. The welding 61 is an inhomogeneous welding, and is carried out during the mounting of the slab from the mounting of the slab 4 to the support mechanism 52 to the mounting and fixing of the pop-out prevention tie beam 54. The welding 61 can be performed because a free space is provided in the upper peripheral portion between the outer peripheral portion of the slab 4 and the fixed structure 2 of the reactor.

After carrying out the seal welding 51, the peripheral free space between the slab 4 and the fixed structure 2 is connected to the peripheral part of the slab 4 by means of a removable closure and filling plug 58 fixed to the fixed structure 2. Filled one by one along. The seal joint 59 is provided on the outer peripheral surface of the slab 4 and the plug 58.
It is provided between the inner peripheral surface of the slab and the plug 58 and can maintain the hermeticity of the slab and the plug 58.

By providing and fixing the slab shown in the figure, the whole slab can be disassembled and lifted. Thus, the entire inner cross section of the container can be accessed, for example disassembling and withdrawing internal structural elements.

All supporting surfaces of the internal structural elements which support each other or are supported on the inner surface of the container are located in what is called the "cold area". In that area, the temperature of liquid sodium is about 4 during reactor operation.
Since it is 00 ° C., it is significantly lower than the temperature of sodium in the hot tank on the outlet side of the core, for example.

A large rotary plug 8 of a nuclear reactor is shown in FIGS. 15 and 16, the plug being mounted for rotation in the central part of the slab 4, the peripheral part of the slab being the primary pump 5 and The intermediate heat exchanger 6 is passing through. In the two areas radially facing each other on the edge of the rotating plug, the slab 4 comprises two cavities,
Decomposable protrusions 60a, 60b made of steel and having a thickness almost the same as the thickness of the slab 4 can be inserted into the cavity.

The large rotating plug 8 can be disassembled by disassembling the plug-cover 10 in the central portion of the core, lifting and then disassembling it from the slab. After disassembling the large rotating plug and lifting it, and then disassembling the protrusions 60a and 60b,
An opening of sufficient size can be provided in the radial direction to allow the girder 12 to be tilted vertically therethrough, and a lifting device can be used to remove the girder 12 from the main container.

FIG. 15 is a vertical sectional view of the girder 12.
2'is shown and this girder is located inside the opening of the large rotating plug 8 which extends radially due to the two mounting cavities of the dismountable projections 60a, 60b. After shutting down the reactor and cooling it, all the assemblies can be taken out of the core of the reactor and stocked in a temporary storage site using the reactor fuel charger.

After that, the large rotary plug and the disassembling projections 60a and 60b can be disassembled and stocked in a temporary storage space. This will allow access to the inside of the container so that the girder can be moved to the vertical position and then withdrawn. These operations are preferably carried out in an inert gas atmosphere after the sodium has been completely discharged from the container.

To disassemble and pull out the girder, the girder is freely attached to the floor plate, and the central pivot 12a attached to the attachment parts and the three central plates 37 attached to the three piping ports of the pipe 35 of the floor plate 37, respectively. Since it is equipped only with this, no disassembly work of the welded joint or the mechanical joint is required. To disassemble the internal structural element assembly, it is necessary to disassemble and lift the reactor slab, but the maintenance and support elements are attached to the fixed structure slab of the reactor. can do.

FIG. 17 illustrates each internal structural element in the raised position inside the container during the drawing operation. FIG. 17 does not correspond to the actual disassembly stage of the internal structural elements, but shows the disassembly sequence of these internal structures performed after the lifting of the reactor slab.

First, as described above, the girder 12 can be lifted and pulled out. This withdrawal can be done by opening the plug without lifting the slab or by opening the container after lifting the slab.

Similarly, the sodium guiding cylinder 22 for cooling the container or the inner container 16 can be disassembled by a simple lifting operation because there is no supporting element other than the internal structure. These two elements 16,22
Are independently attached to the base plate 13, so it is not important which one is to be disassembled first.

After disassembling the elements 12, 16, 22 the main container 1
It is possible to disassemble the base plate 13 attached only to the inner part 28 of the. Finally, the recovery device 15 attached to the support plate 24 connected to the bottom of the main container 1 can be disassembled.

Withdrawal of all internal structural elements can be carried out without disassembling the welded or mechanical joints. In fact, each internal structural element is attached by a maintenance and support mechanism to another internal structural element or to a portion of the interior surface of the reactor vessel. The support by the inner surface of the container can be reliably performed by a support mechanism such as a portion 28 protruding from the inside of the main container or a support plate 14 connected to the container bottom.

The support mechanism for the internal structural elements is usually composed of an annular flange or the end of a tubular body, and is realized by forging or machining. The contact and centering surfaces of the support mechanism are machined on a high precision lathe to allow accurate maintenance and centering of internal structural elements.

Due to the high machining accuracy of the support surface, the assembly and disassembly of the internal structural elements can be carried out easily under favorable conditions. Aluminized plates are placed between the contact surfaces of the support mechanism of the internal structural elements to prevent stainless steel from contacting each other in the container.

High precision machining of some of the components that make up the internal structural elements using forgings simplifies the manufacturing of the internal structure and also provides extremely high accuracy in flange geometry and dimensions. Therefore, the work such as welding of the plate and the flange can be a fully automatic work. Also,
A highly accurate annular space can be provided between the internal structural elements.

Machining can be done at the factory or at the reactor site using a large capacity vertical lathe. To improve the bond between the forged and machined flange and the plate before welding, cold-roll the steel plate of the plate, at least near the bond site, to improve the toroidal shape of both faces. it can. The development of the barrel is then measured to accurately calculate the machining radius of the joint of the forged flange. Then, the connection will be perfect, and it will be possible to use an automatic welding method such as TIG in a narrow space.

The internal structural element according to the present invention is, for example, T
The arrangement is such that welding of a plurality of branched joint parts having a mold section is not required. Similarly, there is no need to thicken the metal at the bonding site. Also,
Except for difficult bond sites, it is much easier to weld.

Due to the large diameter of the support mechanism for the internal structural elements according to the present invention, the dimensions of the support surface are large,
On the other hand, the contact pressure remains small and the capacity is 50%.
In the case of a 0 MWe fast neutron reactor, this contact pressure remains below 3 MPa. Also, an aluminized plate is inserted between the forged support parts of the internal structural elements to avoid any contact that may result in seizure, eg stainless steel.

The concept of internal structure according to the present invention further comprises
It is possible to optimize the substructure of large components of the reactor, that is, the primary pump and the intermediate heat exchanger. As mentioned above, it is also possible to use a bowl-shaped container having a relatively flat bottom. With such a shape, the length dimension of the component can be maximized if the component is arranged over the entire height of the container up to the vicinity of the flat bottom. In this way, the diameter of the components and the overall reactor block can be reduced, and the height of the vessel can be kept practically the same as that of existing techniques.

The use of each of the internal components, which have been partly precision machined, allows the density of the internal structure to be very high, so that it is used for the diameter of the main container and for the manufacture of the container and the internal structure. The weight of the material can be reduced. Similarly, the size of the closed slab of the vessel and the size of the reactor building can be reduced.

Lifting the internal structural elements away from each other is possible not only when pulling the elements out of the container, but also when accessing another element below the lifting element or the bottom of the container. . Machining around the support surface not only allows the internal structural elements to be perfectly bonded to each other, but also provides a leak tight seal from the reactor without the use of joints or other sealing elements. Like

The invention is not limited to the implementation method described above. For example, it is also possible to envisage the use of internal structural elements whose shape differs from that described above and which also comprises different support features. The present invention is generally adapted to any integrated fast neutron reactor, regardless of the number of primary pumps or intermediate heat exchangers used in the main reactor vessel.

[Brief description of drawings]

FIG. 1 is a front vertical sectional view of a container and an internal structure of a fast neutron reactor according to the present invention.

FIG. 2 is a vertical cross-sectional view of a portion of the internal structure of the main container and near the lower end of the pump.

FIG. 3 is a longitudinal sectional view of a part of the internal structure near the lower end of the main container and the intermediate heat exchanger.

FIG. 4 is a longitudinal cross-sectional view of a portion of the internal structure showing the sodium conduit for cooling the main vessel.

FIG. 5 is a vertical cross-sectional view of another portion of the internal structure similar to that of FIG. 4, showing a sodium conduit for cooling the main container.

6 is a cross-sectional view taken along the arrow 5-5 in FIG.

FIG. 7 is a diagram according to arrow 6 in FIG.

FIG. 8 is a vertical cross-sectional view of a part of the internal structure of the nuclear reactor that supports the core.

9 is an enlarged view showing details of FIG. 8. FIG.

10 is a diagram indicated by an arrow 9 in FIG.

FIG. 11 is a half longitudinal cross-sectional view of a part of the internal structure forming the liquid metal pipe for cooling the main container.

12 is a cross-sectional view taken along the arrow 11-11 in FIG.

FIG. 13 is a top view of a closed slab of a reactor vessel.

FIG. 14 is a partial cross-sectional view of the periphery of a closed slab of a reactor vessel.

FIG. 15 is a top view of a portion of a closed slab of a nuclear reactor.

16 is a partial vertical cross-sectional view taken along the arrow 15-15 in FIG.

FIG. 17 is a cross-sectional view of the main vessel and internal structure of a nuclear reactor showing the disassembly order of internal structural elements.

[Explanation of symbols]

 1 Main Container 4 Closed Slab 5 Primary Pump 6 Intermediate Heat Exchanger 6b Outlet Opening 6c Protective Plate 11 Core 12 Girder (Supporting Element) 12a Central Pivot 13 Floor Plate (Supporting Element) 14 Support Plate 15 Waste Material Recovery Device 16 Inner Container 16a Stage 16b outer cylinder 16c inner cylinder 19a / 19b area 22 cylinder 22a, 27, 36 maintenance / support mechanism, circular flange 24 casing 25 induction pipe 26 support plate 27 support mechanism 28 support surface 30 pipe 33 circulation space 34, 42 key 35 Piping Port 36 Annular Flange 37 Seal Ring 38 Support / Waterproof Joint 39 Joint 52 Support Mechanism 54 Tie Beam 60a, 60b Closure Protrusion

Claims (21)

[Claims] 1. A main vessel (1) containing a reactor core (11) submerged in a cooling liquid metal, and at least one unit for circulating the cooling liquid metal in the main vessel (1). A primary pump (5), at least one intermediate heat exchanger (6) submerged in a cooling liquid metal, internal structural elements mounted in the main container (1), and a main container (1) A large metal element assembled therein, and further, in the main vessel (1), an area (19a) for receiving the heated liquid metal exiting the core and a cooled exit from the intermediate heat exchanger (6). An inner vessel (16) forming an area (19b) for receiving the liquid metal, a tube (22) for piping the cooling liquid metal in contact with the inner wall of the main vessel (1), and a supporting element for the core (11). (12, 13) and each internal structural element (1 , 13,16,15,22) is,
For fixing by simple support inside the main container (1), the main container (1) and internal structural elements (12, 13, 1)
5, 16 and 22), an integrated fast neutron reactor comprising a holding and supporting mechanism (22a, 27, 36) for a corresponding mechanism of at least one component of the assembly. . 2. Each internal structural element (12, 13, 15, 1)
6. Reactor according to claim 1, characterized in that the support mechanism according to (6, 22) comprises at least one contact surface machined with high precision. 3. Structural elements (12, 13, 15, 16, 2)
The nuclear reactor according to claim 2, wherein the machined contact surface of the support mechanism of 2) is lathe-machined. 4. Internal structural elements (12, 13, 15, 1)
Reactor according to any one of claims 1 to 3, characterized in that at least one support mechanism (6, 22) is a forged and machined circular flange (22a, 36). 5. Core support element (12, 13) comprises a floor plate connected to a conical support plate (26), said conical support plate having a circular flange (27).
A support mechanism comprising: the circular flange (27) having a support surface disposed on the toric surface of the portion (28) formed by forging and machining the side wall of the main container (1). The nuclear reactor according to any one of claims 1 to 4. 6. The core support element (12, 13) comprises a girder (12) for mounting the lower part of the fuel assembly, ie the legs, which girder is horizontal to the floor plate (13). The base supported on the upper plate, at least one central pivot (12a) combined with a mounting part fixed to the upper plate of the floor plate (13), and the girder (12) include the pivot (1).
Reactor according to claim 5, characterized in that it comprises at least one key for preventing rotation with respect to the floor plate (13) about 2a). 7. At least one liquid sodium induction pipe (25) arranged in a girder (12) below a reactor core (11) is fixed to a floor plate (13), and has a pipe at one end thereof. A mouth (35) is provided and a girder (12) is provided at the position of the liquid metal passage opening.
A seal ring (37) is installed in the opening of the girder (12) with a gap in the radial direction and has an inner hole for attaching the piping port (35) of the floor plate (13). (37) has a support and waterproof joint (38) arranged on the girder (12) and a radially deformable joint (39) in order to ensure the hermeticity around the piping port (35). The nuclear reactor according to claim 6, comprising: 8. The floor plate (13) comprises a liquid metal pipe (30) for cooling the inner wall of the main container (1), one end of the pipe (30) being fixed to the lower portion of the floor plate, The other end of (30) communicates with the circulating space (33) for cooling sodium on the inner wall of the main container (1) so that the floor plate (2) on the support mechanism (28) protrudes inside the inner container (1).
The reactor according to any one of claims 5 to 7, which is inserted into a through opening of the support mechanism (27) of 6). 9. A cylindrical inner cylinder (16) in which the inner container (16) is arranged coaxially to one another by a step (16a).
c) and an outer cylindrical body (16b) having a cylindrical shape, and the support mechanism of the inner container (16) is composed of an annular flange (36) having a support surface arranged on the peripheral portion of the floor plate (13). The nuclear reactor according to any one of claims 5 to 8, which is characterized by being provided. 10. The step (16a) of the inner container (16) comprises:
The nuclear reactor according to claim 9, wherein the nuclear reactor is composed of a flat annular plate. 11. Reactor according to claim 9, characterized in that the steps (16a) of the inner vessel (16) consist of conical plates. 12. A pipe (22) for piping of sodium for cooling a container is provided with a conical support plate (2) at its lower part.
Supporting mechanism (2) for the floor plate (13) fixed to the end of (6)
Reactor according to any one of claims 5 to 11, characterized in that it comprises a support mechanism (22a) having a flat toroidal support surface which is supported on the corresponding toroidal plane of 7). . 13. Waste core material in which internal structural elements are additionally unconstrained mounted on a support plate (14) coaxially fixed to the main vessel (1) at the bottom of the main vessel (1). Reactor according to any one of claims 1 to 12, characterized in that it comprises a recovery device (15). 14. A pump casing (24) has a liquid metal induction pipe (2) opposite the joint of the pipe (35).
8. Reactor according to claim 7, characterized in that it is fixed to the end of (5) and the lower end of the primary pump (5) is attached. 15. The conical support plate (26) of the floor plate (13) is provided with openings for the intermediate heat exchanger (6), and the protective plate (6c) is further provided with an intermediate heat exchange. Bowl (6)
13) Fixed to a conical support plate (26) at the position of the opening for the intermediate heat exchanger facing the outlet opening (6b) of the said. The nuclear reactor described in Crab. 16. At least two of the mutually supporting elements in the main container (1) and the internal structural elements (12, 13, 15, 16, 22) are provided with facing tenon grooves in the supporting position. 16. The nuclear reactor according to claim 1, wherein rotation of the two elements is prohibited by inserting keys (34, 42) into the facing mortises. 17. The support mechanism for the internal structural elements and the elements of the main container (1) comprises an aluminized plate between each contact surface for separating the contact surfaces of the support mechanism. Claim 1 to Claim 1 characterized by
6. The nuclear reactor according to any one of 6. 18. The main container (1) according to any one of claims 1 to 17, wherein the main container (1) has a cylindrical shape as a whole, and has a flat bottom plate-like end plate shape. Reactor described. 19. Reactor according to claim 18, characterized in that the pump (5) and the heat exchanger are arranged along substantially the entire axial height of the vessel (1). 20. The main container comprises a closing slab (4) consisting of a flat plate made of very thick steel, said plate disassembling the slab (4) to open the upper end of the container (1). A support mechanism (52) that slides and rotates, and a tie beam (54) screwed to the fixed structure (2) of the reactor, as claimed in claim 1, characterized in that Item 20. The nuclear reactor according to any one of Item 19. 21. A circular-shaped plug (8) is removably and removably mounted in the opening of the slab of the closure slab (4) which is diametrically elongated by two grooves. Inside, there is a disassembleable closure projection (60
21. Reactor according to claim 20, characterized in that a, 60b) are each fixed.