JPS6190096A - Intermediate heat exchanger - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a tank! The present invention relates to an intermediate heat exchanger that exchanges heat between a primary coolant and a secondary coolant heated in a reactor core in a fast breeder reactor.

[Technical blue use of invention]

Figure 3 shows the schematic configuration of a tank-type fast breeder reactor.
A reactor core 2 that generates thermal energy through nuclear reactions is configured inside the main vessel 1 . In addition, inside the main container 1, there are a plurality of primary main circulation pumps 3 that circulate liquid metal (usually liquid false thorium) as a primary coolant, and liquid metal (usually liquid A primary cooling system facility consisting of a plurality of intermediate heat exchangers 4, etc., which transfers thermal energy to the heat exchanger (1-lium) is accommodated.

A plenum part 5 is provided in the lower part of the core 2, and the core 2 and the plenum part 5 are supported by a core support 6 provided at the bottom of the main vessel 1, and a plenum part 5 is provided above the core 2. A structure 7 is disposed in the upper part of the reactor core, which has a large number of window holes.

- Inside the main container 1, a partition wall 8 supported by partition wall supports 8Δ is arranged horizontally. The partition wall 8 divides the space inside the main container 1 into an upper hot pool 9 and a lower cold pool 10.

The plurality of primary main circulation pumps 3 and the plurality of intermediate heat exchangers 4 are arranged in the main container 1 at equal intervals in the circumferential direction. In addition, at the bottom end of each main circulation pump 3, there is a furnace piping 1.
1 is connected, and the lower end of this pipe 11 extends into the cold pool 10 and is connected to the blennium section 5.

Then, a thin-walled cylindrical body 12 is surrounded from the lower part of each main circulation bomb 3 to the furnace piping 11, and the lower end of this cylindrical body 12 is introduced into the cold pool 10 through the partition wall 8, and the cylindrical body 12 is connected to the interior space of the pool 10.

The outside of the main container 1 is provided with I(
Additionally, a guard vessel 13 is installed.

And the main container 1 made as above is KiPL:j
It is housed in the I-A-R 14.

Furthermore, the space between the upper parts of the key ↑ and the upper part of the door 14 is closed by a roof slab 15, and the upper opening of the main container 1 is also closed by this roof slab 15.

The hot pool 9 and the hot pool 1 contain liquid metal (usually liquid sodium) 6 as a primary coolant, and a cover gas is filled between the liquid level of the liquid metal 6 and the roof slab 15. has been done.

The conventional tank-type fast breeder reactor configured as described above operates as follows.

First, the liquid metal 16, which is the primary coolant, reaches a high temperature as it passes through the reactor core 2 upward as it receives heat from the nuclear reaction. flow inward. Then, it flows into the intermediate heat exchanger 4 through the plurality of suction ports 17, spreads thermal energy to the liquid metal as a secondary coolant, and flows down into the cold pool 10 while avoiding a drop in temperature. On the other hand, the liquid metal 161J in the cold pool 10 is subjected to gastric pressure by the next W1Cr pump 3,
It is returned to the plenum section 5 through the furnace piping 11. In addition,
The liquid metal as a secondary coolant heated in the intermediate heat exchanger 4 is led to the outside of the main container 1 and heats the turbine driving steam.

This intermediate heat exchanger 4 will be further explained with reference to FIG.
The liquid metal 16 as a secondary coolant flows from a plurality of primary coolant populations 17 into the upper chamber 4a of the shell 18 of the intermediate heat exchanger 4, and flows into the intermediate chamber 4a between the upper tube sheet 19 and the upper tube sheet 23.
It flows down through the plurality of heat exchanger tubes 20 installed in the interior of the tube, and then flows out into the lower chamber 4C, and then flows out from the cold N1 outlet 21. On the other hand, liquid metal such as secondary cooling 1.1'l+A flows into the intermediate heat exchanger 4 from the secondary cooling 7.II material population 22, and a plurality of liquid metals such as J5 The air is blown out from the air outlet 24, and the secondary side cold 7J
] Inside the chamber 28, the secondary cooling 7 is carried out while exchanging heat with the liquid metal as the primary coolant described above along the plurality of heat transfer tubes 20.
JI Vj return D 25'r collected, secondary cooling lJI
The material flows out from the material outlet 26. Note that 27 is a shielding material.

[Back? Technical Problems) In the tank-type fast breeder reactor constructed as described above (1), the liquid metal 16 in the hot pool 9 is at a high temperature during operation, and the upper core machine (147 window hole The high-temperature liquid metal 16 flows from there toward the plurality of primary coolant populations 17 of the intermediate heat exchanger 4 in streamlines as shown in FIG.

By the way, at the time of reactor 1 to lip, the nuclear reaction in the reactor core 2 stops, the generated thermal energy rapidly decreases, and the multiple primary heat exchangers of the intermediate heat exchanger 4 are The liquid metal 16 flowing toward the cooling moon inlet 17 is at a low temperature close to the (B claw) of the cold pool 10. In this case, since one of the upper tube plates is connected to the 'FI heat transfer tube 20, The temperature of the upper tube sheet 19 rapidly decreases in response to the decrease in the temperature of the heat transfer tube 20 through which the low-temperature liquid metal 16 passes. The liquid metal in contact with the outer surface is L; (1Lf
Hyperactivity! Shell 18 is left as it is as a zitaka vortex.
will remain at a high temperature for a relatively long time.

For this reason, immediately after the reactor limp, a large temperature buildup occurs between the L shell 18 and the upper tube sheet, which causes thermal stress at the connection between the shell 18 and the upper tube sheet. t
M Jji There is a problem in maintaining the wire properties of the parts.
.

[Purpose of the invention]

The present invention has been made in view of these points, and is based on the average temperature of the upper tube sheet to which the heat transfer tubes of Fl number are connected to the trip line 112 of the nuclear reactor, and the temperature of the shell portion connected to this upper tube sheet. The object of the present invention is to provide a highly reliable intermediate heat exchanger that can reduce the thermal stress at the connection portion between the upper tube sheet and the shell by minimizing the difference.

(Summary of the Invention) The intermediate heat exchanger of the present invention includes a cylindrical shell, two upper and lower tube plates that partition the inside of the shell into an upper chamber, an intermediate chamber, and a lower chamber, and these two tube plates. An intermediate tube consisting of a large number of heat transfer tubes that are supported at both ends and are surrounded by both tube sheets, and which connects the upper chamber to the upper chamber, and a double tube that connects the intermediate chamber to the outside. J3 is placed in the heat exchanger, and the outer part of the seal formed in the lower chamber part from the upper part of the cold JJ part to the lower part of the part of the pipe bundle is filled with 75 parts. A flow skirt is provided between the shells to form 44 flow paths, through which the coolant flows into the shell from the bottom through the cold material inlet. It is characterized by what it did.

Immediately after the reactor trip, the upper part of the reactor core (liquid metal flowing out from 14 - Rudopool? There is a low temperature C close to the quality,
In the present invention, a (A metal is anicolasic cold 19
By flowing through the moon flow path, the temperature of the upper tr (shell connected to the plate and the upper tube plate) is uniformized quickly in order,
Thermal stress generated at the connection between the shell and the upper tube sheet can be kept to a minimum.

[Embodiments of the invention]

1 and 2 show an embodiment of the intermediate heat exchanger of the present invention, and the same parts as in FIG. 4 are marked with the same numerals.

In this embodiment, the intermediate heat exchanger is formed in the same manner as the conventional example shown in FIG. 4, and further includes two flow skirts provided on the outside of the shell 18. The upper part 30 of the flow skirt 29 is hermetically connected to the shell 18 at a position above the primary coolant population 17. on the other hand,
The lower parts of the flow scars 1 and 2 are cut at a position closer to the upper tube plate 19 to form an opening 31.

The flow skirt 29 has an annulus-shaped cold MI +A channel 32 between the outer surface of the shell 18 through which the liquid metal 16 flows through the opening 31 and then flows into the shell 18 from the primary coolant inlet 17. is formed.

Further, the connecting portion between the upper tube plate 19 and the shell 18 is made thinner than before in order to increase the speed at which the temperatures of the upper tube plate 19 and the shell 18 are uniform.

Next, the effect of the nut/one color example will be explained.

During normal reactor operation, as shown in Figure A2, the high-temperature liquid metal 16 flowing from the window hole in the upper part of the core nM tM 7 once descends and flows through the lower openings of the two flow skirts. 2 flow skirts and shell 18
After ascending through the first flow passage 32, the annulus-shaped cooling 741+ consisting of the outer surface of Heat is exchanged with liquid metal as a secondary coolant outside the heat exchanger tubes 20 through the inside of the plurality of heat exchanger tubes 20 connected to the tube plate 19 .

During a reactor trip, the nuclear reaction in the reactor core 2 stops and the generated thermal energy rapidly decreases, so that the temperature 1α of the liquid metal 16 flowing out from the window hole of the structure 7 in the upper part of the reactor core decreases. this]
- The liquid metal 16 at a low temperature close to the temperature of the melted pool 1 is the same as during the reactor street δ operation (, once descends inside the hill 1 - pool 9 L2, between the lower part of Flow Scar i ~ 29 [131
) [] - Up the cold fJI U flow path 32 consisting of the outer surface of the scars 1 to 29 18? ? But during this time, when I was driving, was it Hatake? ! The outer surface of the seal 18, which was +a, is subjected to cold IJI. The liquid metal 16 flowing upwardly in the coolant flow path 32 is transferred from a plurality of primary cooling m 44 to a shell 18.
At this time, this liquid metal 16 flows into the upper part of ``&4a'' and passes through a plurality of heat transfer tubes 20 connected to one upper tube plate. At this time, this liquid metal 16 is heated to The upper tube plate 19 is cooled to 2JI through the F1 heat exchanger tube 20.
be done.

In this example, d3C is hot boolean 9/)
The position of the opening 31 into which the liquid metal 16 of low temperature flows is located below the position of the upper tube plate 19 connected to the inside of the shell 18, and while the liquid metal 16 of low temperature is rising through the coolant flow path 32, The temperature difference between the lζ-sized shell 18 that cools the shell 18 and the upper tube sheet 18 is reduced, so that no large thermal stress is generated at the joint between the shell 18 and the upper tube sheet 19.

Furthermore, by increasing the wall thickness of the connecting portion between the shell 18 and the upper tube sheet 19, the heat capacity rI+ of this portion becomes smaller.
It is possible to quickly respond to a drastic drop in iQ+ of the liquid metal 16 due to a reactor trip, and to quickly equalize the temperatures of the shell 18 and the upper tube sheet 19.

〔Effect of the invention〕

As described above, the intermediate heat exchanger of the present invention has an upper tube plate to which a plurality of heat transfer tubes are connected directly to the lip 19 of a nuclear reactor, and
L81! It is possible to reduce the temperature difference with the shell part connected to the tube sheet, and it is possible to avoid reducing the thermal stress at the connection part of the upper tube sheet and the shell, thereby preventing thermal stress fracture, etc. This brings about effects such as increased reliability.

[Brief explanation of the drawing]

Fig. 1 is a schematic sectional view showing an embodiment of the intermediate heat exchanger of the present invention, Fig. 2 is an enlarged sectional view of the skirt portion of the embodiment of the present invention, and Fig. 3 is a conventional tank. Figure 4 is a schematic cross-sectional view showing the M4 structure of a conventional intermediate heat exchanger; It is an enlarged sectional view of a plate part. 4... Intermediate heat exchanger, 4a... Upper chamber, 4b...
Middle chamber, 4C...lower chamber, 17...-Next cooling shrine [
1, 18...Shell, 19...Upper tube plate, 29...
・Flow skirt, 32...cold IJ1 material flow path. 1st cause 2nd cause 3rd figure 4th figure

Claims (1)

[Claims] 1. A cylindrical shell, two upper and lower tube plates that partition the inside of the shell into an upper chamber, an intermediate chamber, and a lower chamber, and both ends supported by these two tube plates; A large number of heat transfer tubes passing through an intermediate chamber surrounded by both tube sheets and communicating the upper chamber and the lower chamber,
In an intermediate heat exchanger comprising a double pipe connecting the intermediate chamber and the outside, an outer portion of the shell from a portion above a coolant inlet formed in the upper chamber portion to a portion below the upper tube plate. An intermediate heat exchanger characterized in that a flow skirt is provided between the shell and the shell to form an annulus-shaped coolant flow path through which the coolant flows into the shell from the lower part through the coolant inlet. vessel. 2. The intermediate heat exchanger according to claim 1, wherein the wall thickness of the connection portion between the upper tube plate and the shell is made thin.