JPH07119901A - Steam generator - Google Patents

Abstract

PURPOSE:To equalize the diameter of the top to that of the bottom of a steam, generator by reducing a pitch of a heat transfer tube at a body drum through part of a heat transfer tube group disposed in a body drum in which liquid metal cooling medium is supplied shorter than that of a heat transfer tube at a steam tube plate. CONSTITUTION:Heat transfer tubes 3 are arranged linearly up to the bottom of a steam generator in an annular area surrounded by a body drum 4 and an outer shroud 5, and outside of the tubes 3 becomes a retention area 6 of sodium. The tubes 3 are vertically erected above a helical coil tube bundle 8 to form a straight tube part 9, and its end is connected to a steam tube plate 10 through a body drum through part 15. In this case, a pitch of a part 16 which penetrates the part 15 of the tubes 3 is set to a value smaller than that of a part 17 to be connected to the plate 10. Thus, the diameter of the part 15 is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a helical coil type steam generator used in a liquid metal cooling type fast breeder reactor, and more particularly to improvement of a main body penetrating structure of a heat transfer tube group.

[0002]

2. Description of the Related Art A steam generator of a fast breeder reactor is a heat exchanger that heats water with liquid metal such as liquid metal sodium used as a coolant to obtain steam. The structure of this steam generator will be described with reference to FIG. 7, taking as an example a helical coil-type steam generator in which feed water flows in from the upper part and steam flows out from the upper part, using a spiral heat transfer tube.

As shown in FIG. 7, in the present steam generator, the feed water flows into the water feed tube base 1 and is distributed to the plurality of heat transfer tubes 3 in the water feed tube plate 2. The heat transfer tube 3 is linearly arranged up to the lower part of the steam generator in an annular region surrounded by the main body cylinder 4 and the outer shroud 5. The area outside the heat transfer tube in this annular area is a sodium retention area 6. Heat transfer tube 3
Is bent upward in the lower part of the steam generator and reaches an annular region surrounded by the outer shroud 5 and the inner cylinder 7. The heat transfer tube 3 in this region is bent in a spiral shape to form a helical coil tube bundle 8, and the water in the heat transfer tube 3 becomes steam by heat exchange with sodium to the outside. Heat transfer tube 3 above the helical coil bundle
Is erected vertically and connected to the steam tube sheet 10 via the straight tube portion 9. The steam in the heat transfer tube 3 flows into the steam tube base 11 from the steam tube plate 10 provided at the upper part of the steam generator and reaches the outside of the steam generator. On the other hand, sodium flows in from the inlet nozzle 12 in the upper part of the steam generator and exchanges heat with the water in the helical coil tube bundle 8 while flowing down the annular region surrounded by the outer shroud 5 and the inner cylinder 7 to generate steam. It flows out from the outlet nozzle 13 at the bottom of the vessel. The upper end of the outer shroud 5 is
It is provided above the sodium level 14 so that sodium does not flow into the sodium retention region 6 surrounded by the outer shroud 5 and the main body cylinder 4.

[0004]

In the above conventional steam generator, the steam tube plate 10 and the sodium inlet nozzle 1 are used.
Since 2 and 2 need to be provided on the upper part of the steam generator, a large number of holes can be formed at the upper end of the main body cylinder 4, and in terms of strength and manufacturing, the diameter of the upper part of the steam generator is set to the lower part. It must be larger than the diameter. This causes an increase in the size of the steam generator, which causes a cost increase, and also places a large restriction on the arrangement of pipes and the like around the steam generator.

The present invention has been made in view of the above points, and an object thereof is to provide a steam generator capable of making the diameter of the upper portion of the steam generator equal to the diameter of the lower portion of the steam generator. And

Another object of the present invention is to provide a steam generator capable of avoiding the axial extension of the nozzle structure of the upper part of the main body and achieving a compact structure.

Still another object of the present invention is to provide a steam generator which is advantageous in layout design around the steam generator.

[0008]

In order to achieve the above object, the invention according to claim 1 of the present invention is to arrange a heat transfer tube group in a main body cylinder to which a liquid metal coolant is supplied, and to downstream thereof. In a steam generator in which the side of the heat transfer tube group is vertically raised, the body cylinder penetration portion at the upper end of the body cylinder is passed, and the tip of the steam generator is connected to the steam tube base, Is smaller than the heat transfer tube pitch in the steam tube sheet.

According to a second aspect of the present invention, the steam tube sheet is arranged non-perpendicular to the axial direction of the heat transfer tube group in the main body penetration portion, and the heat transfer tube group has passed through the main body penetration portion. Is bent and then connected to the steam tube sheet.

Further, the invention according to claim 3 of the present invention is
The water supply tube plate and the water supply tube base are arranged at the upper end of the main body.

[0011]

In the invention according to claim 1 of the present invention, the heat transfer tube pitch in the main body penetrating portion of the heat transfer tube group is made smaller than the heat transfer tube pitch in the steam tube sheet. Therefore, the diameter of the heat transfer tube penetrating portion can be reduced, and as a result, it is not necessary to increase the diameter of the upper portion of the steam generator.

Further, in the invention according to claim 2 of the present invention, the heat transfer tube group which has passed through the main body penetrating portion is connected to the steam tube sheet after being curved. Therefore, the axial length of the nozzle structure at the upper part of the main body is shortened, and the size can be reduced.

Further, in the invention according to claim 3 of the present invention, the water supply pipe plate and the water supply pipe base are arranged at the upper end portion of the main body barrel. Therefore, the water side nozzle on the side surface of the steam generator can be eliminated, and a steam generator advantageous in layout design can be obtained.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a steam generator according to a first embodiment of the present invention. In the figure, reference numeral 1 is a water supply pipe stub, and water supplied to this water supply pipe stub 1 has a plurality of water supply pipe plates 2. It is designed to be distributed to the heat transfer tubes 3 of the book.

The heat transfer tube 3 includes a body barrel 4 and an outer shroud 5.
It is linearly arranged to the lower part of the steam generator in an annular region surrounded by and the outside of this heat transfer tube 3 is a sodium retention region 6.

The heat transfer tube 3 is bent upward in the lower part of the steam generator, is arranged upward in an annular region surrounded by the outer shroud 5 and the inner cylinder 7, and is further bent in a spiral shape. A helical coil tube bundle 8 is formed. And
The water in the heat transfer tube 3 becomes steam by heat exchange with external sodium.

The heat transfer tube 3 is further provided with a helical coil tube bundle 8
Is erected vertically to form a straight pipe portion 9, and its tip end is connected to the steam tube sheet 10 through a main body penetrating portion 15. Then, the steam in the heat transfer tube 3 flows into the steam tube base 11 via the steam tube plate 10 and is sent out of the steam generator.

On the other hand, sodium flows from the inlet nozzle 12 above the steam generator, and this sodium flows into the water in the helical coil tube bundle 8 while flowing down the annular region surrounded by the outer shroud 5 and the inner cylinder 7. Heat exchange with the steam generator, and then flows out from the outlet nozzle 13 at the bottom of the steam generator.

The upper end of the outer shroud 5 has a sodium level 1 so that sodium does not flow into a sodium retention region 6 surrounded by the outer shroud 5 and the main body cylinder 4.
It extends above 4.

The configuration up to this point is basically the same as that of the conventional steam generator shown in FIG. 7, and this embodiment is different in the following points.

That is, the body body penetrating portion 1 of the heat transfer tube 3
The pitch of the portion 16 penetrating 5 is as shown in FIG.
It is set to a value smaller than the pitch of the portion 17 connected to the steam tube sheet 10, and thereby the diameter of the body barrel penetrating portion 15 is reduced. The pitch of the portion 17 of the heat transfer tube 3 connected to the steam tube plate 10 is gradually widened to match the pitch of the steam tube sheet 10.

As described above, since the diameter of the body barrel penetrating portion 15 can be reduced, it is not necessary to increase the diameter of the body barrel 4 at the upper portion as in the conventional example shown in FIG. 7, and the steam generator can be made compact. can do.

FIGS. 2 (a) to 2 (c) show a second embodiment of the present invention, which is a double tube steam using a heat transfer tube having a double cylindrical structure of an inner tube and an outer tube. It is about the generator.

That is, the heat transfer tube 23 having a double cylindrical structure
The pitch of the portion 16 penetrating the body trunk penetrating portion 15 is small, and the pitch is gradually widened in the portion 17 after penetrating. The outer tube 23a of the heat transfer tube 23 is connected to the first tube sheet 24 via the welded portion 25 as shown in FIG. 2 (c), and the inner tube 23b of the heat transfer tube 23 is shown in FIG. 2 (b).
As shown in, the second tube sheet 26 is connected via a welded portion 27.

As shown in FIG. 2A, the first tube sheet 24 and the second tube sheet 26 are connected by a helium plenum cylinder 28 in which helium gas is enclosed. The difference in thermal expansion between the plenum barrel 28 and the inner pipe 23b inside the plenum barrel 28 is absorbed by the bending of the helium plenum barrel 28. Thus, also in the case of this embodiment, the same effect as that of the first embodiment can be expected.

FIG. 3 shows a third embodiment of the present invention. In order to utilize the cylinder 7 of the first embodiment as a sodium flow path, an electromagnetic pump 30 is provided above the inner cylinder 7. It was done like this.

That is, an electromagnetic pump 30 is internally provided in the upper part of the inner cylinder 7, and the electromagnetic pump 30 is hung from the flange 31 so as to be pulled out from the upper part of the steam generator. Then, sodium flows in from a sodium inlet nozzle (not shown) and exchanges heat with water in the helical coil tube bundle 8, and then the flow path is reversed at the lower part of the steam generator to reverse the inner cylinder 7
It rises inside, reaches the electromagnetic pump 30, is pressurized and flows out from the sodium outlet 32.

As described above, even when the electromagnetic pump 30 is pulled out from the upper portion of the steam generator, it is possible to prevent the diameter of the upper portion of the steam generator from being larger than that of the lower portion.

By the way, in each of the above-mentioned embodiments, as is clear from FIG. 2 showing, for example, the double-tube steam generator, the heat transfer tube 23 is inserted after the main body penetrating portion 15 is penetrated.
Since it is necessary to widen the pitch of the main body, the distance from the body trunk penetrating portion 15 to the tube sheets 24, 26 becomes longer, and the tube sheets 24, 2
There is a problem that the portion including the body 6 protruding from the body barrel 4 becomes long in the vertical direction.

FIG. 4 shows a fourth embodiment of the present invention made to solve such a problem. The steam tube sheet 10 is shown in FIG.
Are arranged at a right angle (parallel in FIG. 4) to the axial direction of the heat transfer tube 3 penetrating the main body penetrating portion 15.
The tip of the portion 16 penetrating the body trunk penetrating portion 15 is curved and connected to the steam tube sheet 10.

As described above, the structure above the body trunk penetrating portion 15 can be made small in the vertical direction, and the upper structure of the steam generator can be shortened to increase the height of the building that houses the steam generator. The cost can be lowered and the transportation cost can be reduced. Further, since the heat transfer tube pitch in the steam tube plate 10 can be secured at the bent portion of the heat transfer tube 3, the production is easy.

FIG. 5 shows a fifth embodiment of the present invention, in which the structure of the fourth embodiment is applied to a double tube steam generator.

That is, the heat transfer tube 23 having a double cylindrical structure.
The pitch of the portion 16 through which the body trunk penetrating portion 15 penetrates is small, and the pitch gradually widens in the portion 17 after penetration. The outer tube 23a of the heat transfer tube 23 is connected to the first tube sheet 24 via the welded portion 25, and the inner tube 23b of the heat transfer tube 23 is not parallel to the first tube sheet 24 (right angle in FIG. 5). It is connected to the second tube sheet 26 installed at 1 through the welded portion 27.

The first tube sheet 24 and the second tube sheet 26 are connected by a plenum cylinder 28 in which helium gas is sealed, and the plenum cylinder 28 and the inner tube 23b therein are connected to each other. The tube plates 24 and 26 are curved so as to smoothly connect them. And the helium plenum 28 and the inner tube 2
The difference in thermal expansion from 3b can be absorbed by this bent portion.

As described above, also in the case of the double tube steam generator, the same effect as that of the fourth embodiment can be expected, and FIG.
Unlike the case of the second embodiment shown in FIG. 7, it is not necessary to provide the helium plenum cylinder 28 with a bulge for absorbing a difference in thermal expansion.

FIG. 6 shows a sixth embodiment of the present invention. Instead of the water supply nozzle 1 and the water supply tube plate 2 in the first embodiment, a water supply nozzle 41 and a water supply tube plate 42 are used. It is the one.

That is, the water supply pipe base 41 and the water supply pipe plate 42 are installed above the steam generator via the main body penetrating portion 43, and the portion 44 of the heat transfer tube 3 penetrating the main body penetrating portion 43. The pitch is set to a value smaller than the pitch of the portion 45 connected to the water supply pipe sheet 42, whereby
The diameter of the body trunk penetrating portion 43 is reduced. The pitch of the portion 45 of the heat transfer tube 3 connected to the supply tube plate 42 is gradually widened to match the pitch of the water supply tube plate 42.

As described above, since the main body penetrating structure of the heat transfer tube 3 can be made compact, the tube plates 10 and 42 can be concentrated on the upper part of the steam generator, and the water side nozzle on the side surface of the steam generator can be eliminated. It is possible to provide a steam generator that is advantageous in layout design.

[0039]

As described above, according to the first aspect of the present invention.
In the invention according to, since the heat transfer tube pitch in the main body penetration portion of the heat transfer tube group is made smaller than the heat transfer tube pitch in the steam tube sheet, the heat transfer tube penetration portion is made smaller in diameter, and the steam generator upper portion is lower than the lower portion. Can be prevented from having a large diameter.

Further, in the invention according to claim 2 of the present invention, since the steam tube sheet is arranged non-perpendicular to the axial direction of the heat transfer tube group in the main body penetrating portion, the main body penetrating portion is The passed heat transfer tube group is curved and connected to the steam tube plate, and the tube base structure in the upper part of the main body can be shortened in the axial direction. Therefore, it is possible to reduce the construction cost by reducing the height of the steam generator and the building that houses the steam generator.

Further, the invention according to claim 3 of the present invention is
Since the water supply pipe plate and the water supply pipe base are arranged on the upper end of the main body, the water side nozzle on the side surface of the steam generator can be eliminated, and a steam generator advantageous in layout design can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view showing a steam generator according to a first embodiment of the present invention.

2A is a sectional view of a steam tube sheet portion showing a second embodiment of the present invention, FIG. 2B is an enlarged sectional view of part A of FIG. 2A, and FIG.
FIG. 7A is an enlarged cross-sectional view of a B part in (a).

FIG. 3 is a view corresponding to FIG. 1 showing a third embodiment of the present invention.

FIG. 4 is a sectional view of a steam tube sheet portion showing a fourth embodiment of the present invention.

FIG. 5 is a sectional view of a steam tube sheet portion showing a fifth embodiment of the present invention.

FIG. 6 is a first equivalent view showing a sixth embodiment of the present invention.

FIG. 7 is a sectional view showing a conventional steam generator.

[Explanation of symbols]

 1,41 Water supply pipe base 2,42 Water supply pipe plate 3,23 Heat transfer pipe 4 Main body 5 External shroud 7 Inner cylinder 8 Helical coil tube bundle 10 Steam pipe plate 11 Steam pipe base 12 Inlet nozzle 13 Outlet nozzle 14 Sodium liquid level 15, 43 Body barrel penetration part 23a Outer tube 23b Inner tube 24 First tube sheet 26 Second tube sheet 28 Helium plenum body 30 Electromagnetic pump 31 Flange 32 Sodium outlet

Claims (3)

[Claims] 1. A heat transfer tube group is arranged in a main body barrel to which a liquid metal coolant is supplied, and a downstream side thereof is vertically raised to pass through a main body barrel penetrating portion at an upper end of the main body barrel and a tip thereof is a steam pipe. A steam generator connected to a steam pipe stub via a plate, wherein the heat transfer tube pitch in the main body penetrating portion of the heat transfer tube group is smaller than the heat transfer tube pitch in the steam tube plate. 2. The steam tube sheet is arranged at a right angle to the axial direction of the heat transfer tube group in the main body penetration portion, and the heat transfer tube group passing through the main body penetration portion is curved and connected to the steam tube sheet. The steam generator according to claim 1, wherein: 3. The steam generator according to claim 1, wherein the water supply pipe plate and the water supply pipe base are arranged at the upper end of the main body barrel.