JPS60263097A - Supporting structure for heat exchanger - Google Patents

Abstract

PURPOSE:To suppress a thermal stress, applied on a connecting part between the supporting structure and a cylinder upon thermal transition, in low and reduce damage due to creep of discontinuous section of the structure by a method wherein the connecting position between the supporting structure and the outer cylinder is positioned at the lower part of the outer cylinder enveloping low-temperature primary cooling agent after exchanging heat. CONSTITUTION:The primary cooling agent, heated by a reactor and becoming high temperature as well as radio active, flows into the outer cylinder 1 through a primary inlet nozzle 2, ascends through annular flow path formed by the outer cylinder 1 and an outer shroud 21, flows into the outer shroud 21 through the inlet window 9 of the outer shroud 21 and flows down under effecting heat exchange between secondary cooling agent ascending through heat transfer tubes 11, thereafter, flows out of the heat exchanger from the primary outlet nozzle 3 of the outer cylinder 1 through an outlet window 10. The cooling agent, flowed out of the outlet window 10 of the outer shroud 21 has a low temperature sufficiently and it is lower than the creep area temperature of the material of the structure, therefore, the heat stress applied on the connecting section may be reduced and the damage due to creep may be reduced sufficiently in case the connecting section of the supporting structure 15 is set at the lower part of the outer cylinder 1, which is lower than a partitioning plate 16.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a heat exchanger, and particularly to a support structure for a heat exchanger.

[Background of the invention]

As a conventional example, FIG. 2 shows an overall structural diagram of a straight pipe type heat exchanger for a fast breeder reactor.

The heat exchanger is suspended from a support structure 15 and has an outer shell 1 having a single water-filling nozzle 2 and a primary output nozzle 3 for the coolant, and a double-water-filling nozzle 4 and a dual-output nozzle 5. An upper mirror plate 20 is connected to the outer shell 1 through the upper tube plate 6 and constitutes the upper plenum 13, and a clay pipe plate 6 is housed in the upper part of the outer shell 1.
A heat exchanger tube bundle 12 installed between the upper tube plate 6 and the lower tube plate 7, a downcomer pipe 17 connected to the two water-filled nozzles 4 and passing through the upper tube plate 6 and the lower tube plate 7, and a lower plenum 14 connected to the lower tube plate 7. The lower plenum mirror 19 forms an internal structure. A steady rest 23 is fixed to the outer shell 1 and prevents the outer shroud 21 from swinging laterally.

Furthermore, a partition plate 16 is provided between the outer shell 1 and the outer shroud 21 to partition the primary coolant before and after heat exchange.

Furthermore, the outer shroud 21 is provided with an inlet window 9 and an outlet window 10 through which the primary coolant flows in and out.

In the heat exchanger configured as described above, the primary coolant heated by the nuclear reactor and activated at high temperature flows into the outer shell 1 from the single water-containing nozzle 2, and flows between the outer shell 1 and the outer kidney. Heraud 21
The coolant ascends through the annular flow path section formed by the cooling material, flows into the outer shroud 21 through the inlet window 9 of the outer shroud 21, and descends while exchanging heat with the secondary coolant rising within the heat transfer tubes 11 in the tube bundle section. Thereafter, it flows out of the heat exchanger from the single-port nozzle 3 of the outer shell 1 through the outlet window 10.

On the other hand, the secondary coolant flows into the heat exchanger from the second medical school nozzle 4, descends in the downcomer pipe 18, is reversed at the F section glenum 14, and then flows into the heat transfer tube 11 and becomes the primary coolant. It rises while exchanging heat, passes through the upper plenum 13, and flows out of the heat exchanger through the two-man nozzle 5.

In such a heat exchanger, even if a coolant leakage accident occurs in the piping on the single person exit side, the coolant level in the core does not drop and the core is exposed. To,
A guard vessel 32 is provided directly below the heat exchanger to store leaked coolant.

Since a structure in which the support structure 15 of the heat exchanger is directly connected to the guard vessel 32 is disadvantageous in terms of earthquake resistance, a hanging type support structure 15 is adopted as shown in FIG. 2.

Conventionally, in consideration of maintainability, the support structure 15 is connected to the upper part of the outer shell 1 as shown in FIG. Coolant is flowing, making strength evaluations such as thermal stress during thermal transients and creep damage evaluation extremely difficult.

Incidentally, a related device of this type is 1 Utility Model Application Publication No. 160585 of 1982.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat exchanger that is capable of suppressing thermal stress applied to a shell joint of a support structure during thermal transients, and reducing creep damage at structural discontinuities.

[Summary of the invention]

A feature of the present invention is that in order to reduce stress generated during thermal transients and creep damage at the joint between the support structure and the outer shell of the heat exchanger, the joint portion of the outer shell of the support structure is subjected to high-temperature primary cooling before heat exchange. The reason is that the low-temperature primary coolant after heat exchange is transferred from the upper part of the outer shell, which contains the material, to the lower part of the outer shell, which contains the low-temperature primary coolant.

[Embodiments of the invention]

A first embodiment of the present invention will be described based on FIG.

A joint between the support structure 15 and the outer shell 1 is provided at the lower part of the outer shell 1 below the partition plate 16.

The first medical school entrance side pipe 2a for the coolant of the nuclear reactor is connected to the first injection nozzle 2 using a penetration part 22 provided in the body of the support structure 15.

In the annular flow path formed by the outer shell 1 and the outer shroud 21, the high temperature primary coolant before heat exchange flows in the upper part with the partition plate 16 as the boundary, and the low temperature primary coolant after heat exchange flows in the lower part. ing.

The coolant flowing out of the exit window 10 in the outer shroud 21 is sufficiently cold to be below the creep region temperature of one structural member. For this reason, if the joint part of the support structure 15 is set at the part of the outer shell that is in contact with the low-temperature primary coolant, not only will the thermal stress on the joint part be reduced, but the creep damage will be sufficiently small, and the structural The reliability of the discontinuity strength is greatly increased.

Next, a second embodiment of the present invention will be described with reference to FIGS. 3 to 8.

The joint between the support structure 15 of the heat exchanger and the outer shell 1 is moved to the lower part of the outer shell 1 where the temperature is low, and a W-proof structure 24 is further provided between the support structure 15 and the outer shell 1.

4 and 5 show the first example of the earthquake-resistant structure 24.
Figure 5 shows an earthquake-resistant structure with a pin structure. A support protrusion 25 is fixedly installed on the body portion of the support structure 15 and the outer body 1, and a support rod 26 therebetween is joined with pins 25a and 25b.

Since it is a pin connection, it can be removed if it becomes a hindrance during maintenance.

A second example of the earthquake-resistant structure 24 is shown below based on FIGS. 6 and 7.

This second example is a bifurcated bracket 15a with salt 9 attached to the support structure 15, and a bracket 15 attached to the outer shell 1.
The structure is such that the outer shell 1 is sandwiched with a gap t, and displacement in the radial direction due to thermal expansion of the outer shell 1 is allowed to escape by the dimension t, but displacement in the circumferential direction is restrained.

A third example of the earthquake-resistant structure 24 is shown below based on FIG.

The damper 27 installed horizontally between the outer shell 1 and the support structure 15 using pins 27a and 27b has a structure that allows slow displacement such as thermal expansion, but does not allow sudden displacement such as that caused by earthquake force. As the damper 27, a known oil damper cylinder device can be used.

Since the damper 27 is usually quite large, the outside 1Ili
11 and the support structure 15 may not fit. In that case, the support structure 15 is provided with a protrusion 28 to accommodate the damper 27. Fast breeder reactor IC! ! Due to space limitations indoors, it is not possible to increase the size of the entire support structure 15. Therefore, the support structure 15 is partially provided with projections 28, and the space inside the projections is sufficient for maintenance and for damper 27. It has a force gap that allows it to be removed.

By providing one of the seismic structures shown above, it is possible to connect the outer shell 1 of the heat exchanger with the support structure 15 whose plate thickness and radius are larger than that of the outer shell 1. Since the rigidity of the outer shell is increased by the connected structure, the conventional outer shell 1
The seismic sabot installed in the center and connected to the building can be omitted. In order to increase rigidity, the height of the connection part of the earthquake-resistant structure 24 to the outer shell 1 is set to be the same as or close to the height of the upper tube plate 6.

A third embodiment of the present invention will be described below with reference to FIG.

The joint between the support structure 15 of the heat exchanger and the outer shell 1 is connected to the lower tube plate 7.
It was installed in one part of the outer body at the height of the steady rest 23.

With this structure, the moment force at the joint due to the swinging force generated in the lower tube plate 7 can be reduced, and the seismic strength is increased.

In addition, by manufacturing the joint portion of the outer shell 1 and the steady rest 23 by integral forging, the cost and manufacturability of the heat exchanger are improved.

The fourth embodiment of the present invention shown in FIG. 10 is a partial modification of the previous third embodiment, and the modification is
This is because a manhole 29 has been installed in the fuselage.

Due to space constraints, it is not possible to make the support structure 15 too large, so the gap between the support structure 15 body and the outer body 1 can be kept small. Work in the aforementioned gap can be easily carried out.

The M5 embodiment of the invention shown in FIG. 11 is as follows.

Generally, austenitic stainless steel is used as a structural material for a heat exchanger for a fast breeder reactor. Sufficient strength can be obtained by using austenitic stainless steel, but when the overall length of the support structure M15 fuselage is large as in the present invention, it is desirable to construct the entire body from expensive austenitic stainless steel. do not have. Therefore, by providing a dissimilar metal welding joint part 30 in the support structure part 15 and making the entire part on the side of the flange 8 from this joint part 30 to be made of inexpensive carbon steel, the total cost can be kept lower than that of the conventional structure. In this example, by sufficiently lowering the temperature of the primary coolant inscribed in the joint portion of the support structure 15 compared to the conventional example, the thermal stress generated in the support structure 15 is suppressed to a sufficiently low level, so that it can be used as a structural material. This made it possible to introduce carbon steel.

The sixth embodiment of the present invention shown in FIG. 12 is as follows.

By moving and installing the one-bottom nozzle 2 and the partition plate 16 higher than before, the material for the support structure 15 is minimized.

The seventh embodiment of the present invention shown in FIG. 13 is as follows.

The heat exchanger support structure 15 is installed directly on the building floor from one part of the outer shell below the partition plate 16. The one-person nozzle 3 is provided beside the outer shell 1 so as not to interfere with the support structure 24. Furthermore, the upper part of the single-person exit side piping 31 is in an inverted U-shape, and a siphon break structure 34 is provided at the top for the outside air inlet 331, and gas from outside the tube 31 is introduced into the piping from the outside air inlet 33 at the same time as leak detection. This makes it possible to prevent the coolant from flowing from the furnace vessel to the heat exchanger due to the siphon effect, and the guard vessel 32 becomes unnecessary. As the outside air inlet 33, an electric valve that connects the pipe 31 and the outside of the pipe 31 can be used.

This makes it possible to adopt a structure in which the heat exchanger is supported from below.

In order to improve earthquake resistance, an earthquake-resistant structure 24 is installed on the upper part of the outer shell 1.

In each of the above embodiments, the fluid to be cooled (primary coolant) is a coolant for a fast breeder reactor, but it may also be a coolant for something other than a fast breeder reactor or a fluid used for something other than a nuclear reactor. It's okay to have one.

〔Effect of the invention〕

According to the present invention, in a heat exchanger, it is possible to suppress the thermal stress that occurs at the joint between the supporting structure and the shell during thermal transients, and also to reduce creep damage in the Hakuzo non-delayed connection part, so that structural discontinuity is achieved. This has the effect of greatly improving the reliability of part strength.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a heat exchanger according to a first embodiment of the present invention, FIG. 2 is a longitudinal sectional view of a conventional heat exchanger, and FIG. 3 is a longitudinal sectional view of a heat exchanger according to a second embodiment of the invention. Longitudinal cross-sectional view, Figure 4 is the 3rd
Figure 5 is a plan view showing the first example of the earthquake-resistant structure shown in Figure 4.
Figure 6 is a plan view showing the second example of the earthquake-resistant structure shown in Figure 3, Figure 7 is an elevation view of Figure 6, and Figure 8 is the earthquake-resistant structure shown in Figure 3. FIG. 9 is a vertical cross-sectional view of a heat exchanger according to a third embodiment of the present invention, and FIG. 10 is a vertical cross-sectional view of a heat exchanger according to a fourth embodiment of the present invention. , FIG. 11 is a vertical sectional view of a heat exchanger according to a fifth embodiment of the present invention, and FIG.
2 is a vertical sectional view of a heat exchanger according to a sixth embodiment of the present invention,
FIG. 13 is a longitudinal sectional view of a heat exchanger according to a seventh embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Outer body, 2... 1 bottom nozzle, 6... Upper tube plate, 7... Lower tube plate, 8... Flange, 15... Support structure, 16... Partition Plate, 21... External shroud, 23... Steady rest part, 24... Earthquake resistant structure, 26.
...Support rod, 27...Damper, 28...Protrusion, 2
9... Manhole, 30... Dissimilar material joint, 31...
・1 Inu Yamaguchi side piping. Agent Patent Attorney Akio Takahashi $ J Law 4 Figure 11

Claims (1)

[Claims] 1. The outer shell is provided with a gap for receiving the fluid to be cooled before cooling and a gap for receiving the fluid after cooling between the outer shell and the inner structure of the outer shell, and the outer shell is supported by a support structure attached to the outer shell. A support structure for a heat exchanger, characterized in that the support structure is attached to the outer body portion facing the gap that receives the cooling after cooling.