JPS60238683A - Intermediate heat exchanger for fast breeder reactor - Google Patents

Abstract

PURPOSE:To improve the reliability at the shutdown of a fast breeder reactor and at the trouble of a primary coolant circulating pump and the like and at the same time prevent the cost from heightening by a structure wherein the titled heat exchanger is horizontally installed and equipped with two water chambers, on one of which the primary coolant circulating pump is vertically assembled and in the other chamber of which a backward flow preventing check valve for primary coolant is assembled so as to be at a state to communicate through another primary coolant passage with the circulating pump. CONSTITUTION:The titled heat exchanger is horizontally installed and equipped with two water chambers 20d and 20f, both of which are communicated through the primary coolant passage formed in the inside of a heat transfer pipe with each other. A primary coolant circulating pump 30 is vertically assembled in the one water chamber 20d. A backward flow preventing check valve 22 for primary coolant is assembled in he other water chamber 20f so as to be at a state to communicate through another primary coolant passage with the circulating pump 30. Consequently, the center distance between a fast breeder reactor and an intermediate heat exchanger can be shortened, resulting in making the diametr of the containment vessel of the nuclear reactor as small as possible and accordingly lowering the construction cost of the nuclear reactor. In addition, the reliability to the loss of coolant accident at the trouble of the pump, the shutdown of the nuclear reactor and the like can be strikingly improved.

Description

[Detailed description of the invention] a.) B. Field of application in industry Book) I. An intermediate heat pump incorporating a pump that circulates the next cooling ladle into a fast breeder reactor. It concerns exchangers.

b. Prior art No. u 1% 1 outlines a conventional reactor flant main cooling system using this intermediate heat exchanger. That is, in FIG. 41, l is a vertical intermediate heat exchanger, J is a circulation pump, and the circulation pump 3 has its motor 3a at the top and the impeller part 3b at the bottom. It is installed so that it is located in the center of the converter. In order to circulate the primary coolant to the reactor/intermediate heat exchanger J by the circulation pump 3, the reactor outlet pipe S exits from the upper part of the reactor/towards the intermediate heat exchanger J, and from the bottom thereof. The J Kyoko reactor inlet pipe q enters the intermediate heat exchanger and is connected to the impeller part 3b, while the J Kyoko reactor inlet pipe q is connected to the reactor outlet pipe and the reactor outlet pipe connected to the impeller part 3b.
Left standing part, intermediate heat exchanger surrounding ta - Inner cylinder b
It extends from the bottom in an inverted U-shape and extends into the reactor from the top. A reverse valve 6 for preventing backflow of the primary cooling phase is stacked on the horizontal part a of the U-shape.

The intermediate heat exchanger has upper and lower tube plates c, 2d, an outer cylinder 2a, and an inner cylinder l? Water type e due to b etc.

and a heat exchange area - g lJ' - is defined. An outlet nozzle h and an inlet nozzle 1 for a secondary coolant, which are connected to piping to a steam generator (not shown), are attached to the water chambers e and f in communication with each other, and the water chambers e and f are connected to each other in communication with each other. In the figure, a tube support plate jj is installed (a large number of heat exchanger tubes (not shown) are disposed in communication with the water chambers E and F.

Therefore, during normal operation of the nuclear reactor, by driving the pump 3,
The primary coolant inside the reactor follows the outlet pipe S to the pump 3.
is sucked in from the impeller part 3b of the pump bearing part 3C.
It enters the heat exchange area 2g from an unillustrated discharge port located at
Then, after exchanging heat with the secondary coolant that enters from the input nozzle 71 and exits from the outlet nozzle and 2h, it passes through the reactor pipe and returns to the inside of the reactor. Performs a prescribed cooling action.

C1 Points to be solved by the invention However, in the conventional main cooling system with the above-mentioned equipment configuration, there are the following points of concern, and the corner! One decision was expected.

(1) The check valve 6 is installed in the horizontal section 14a of the inlet piping between the reactor and the intermediate heat exchanger. The diameter becomes large and the cost becomes very high.

(2) When the pump 3 is started, the surplus 1 receiving part JC is in the liquid as shown in the figure 8 in the relevant Jj3i′g section, that is, the liquid level in the reactor /J( It is necessary that the intermediate heat exchanger be located below the liquid level during normal operation (which is reduced by the volumetric shrinkage of the primary coolant due to the drop in temperature), but the intermediate heat exchanger must be placed vertically. Since the pump bearing part 3c is inserted into the center, the vertical center 15 of the heat transfer tube group without any bends is tilted -F, and the center of the reactor core/l is 11/-.
The head H necessary for natural circulation cannot be obtained between the two, and there is a problem with reliability in the event of reactor shutdown, pump failure, etc.

(3) In addition, the intermediate heat exchanger ko includes an outer cylindrical core a and an inner cylindrical core b, and the pump impeller part 3 located at the upper part of the inner cylinder 2b.
In b, since the outlet piping rising part 3a is connected through the inside of the inner cylinder b, the outer diameter of the intermediate heat exchanger B becomes very large, and the amount of material in the structure increases. There is an increase in costs due to increased inventory.

d. Means for solving the m1M1 point" - In order to solve the above-mentioned point, the intermediate heat exchanger for a fast breeder reactor according to the present invention communicates through the primary cooling control 1ffH path inside the heat transfer tube. It has two ice chambers and is stored horizontally, one ice chamber has a primary cooling scoop and circulation bonno built in vertically, and the other ice chamber has a primary cooling scoop. This is also characterized by the fact that the check valve for backflow prevention of @Kori is connected to another primary cooling + connection path and is connected to the circulation pump. .

0, Effect 1 Pump J! Primary cooling from the reactor (
is sucked into the pump from one ice chamber 1ii1, passes through the primary cooling passage connecting the pump and the check valve, reaches the check valve in the water capital, and then passes through the heat transfer tube. , enters one of the ice chambers, and from there returns to the reactor, while exchanging heat with the secondary cooling 1A on the outside of the heat transfer tube, as is well known in the art.

Since the check valve is located inside the water chamber, it does not become a factor in increasing the size of the reactor containment vessel, and the intermediate heat exchanger is housed horizontally, while the primary cooling passage ring pump is placed vertically in a separate ice chamber. Since the intermediate heat exchanger is located in the center of the reactor, it is possible to have a sufficient head space between it and the center of the reactor core, which is necessary for natural circulation.Also, since there is no inner cylinder inside the intermediate heat exchanger, it is possible to downsize the intermediate heat exchanger. can.

f. Example Next, a preferred example of the intermediate heat exchanger according to the present invention will be described with reference to FIGS. 1 to 3. In FIG. The inside of the exchanger θ is divided into a first water chamber JOd, a heat exchange area Oe, and a λ-th water chamber θf by the front plates Ob and Oc.

The first water chamber 2'Oa includes a secondary cooling circulation bonnet 3. 0, the impeller part IJOn is placed in the first water chamber - (7d) at position i+'i', and the
t', < ii, 41 ki'l is disturbed. Part of this impeller, 70a, is connected to the reactor outlet 'f'j' 3K as described for No. A secondary cooling passage J/ is provided at the outlet JOb of the primary cooling passage to be pumped, and the passage JJ2914 is as follows:
The shield plate Jθ is extended longitudinally through the center of the heat exchange area 0e, passes through the tube plate ob, and opens into the first water chamber θd. θd is pivoted in the housing θd so that it can swing and be detached.
A check valve is provided which has a letter-shaped valve body 2b and a dowel bottom C provided at one end of the valve body to prevent hunting, and the valve body 2b is connected to the opening of the passage 7. is urged by Dashibot Coco C in the direction of closing. The housing (a) is attached to the upper part of the water volume, 2of, and its top is usually closed with a lid (d). It becomes possible to take out the valve body 2 (b) to the lid 26 part. q is the atomic insertion [
], and is connected to the first ice chamber -θd on the pump side.Although not shown, the tube plate. b and co. A large number of heat exchanger tubes whose ends fit into the holes provided in the tube plate C, Ob and 2
The first water chamber θd and the second water chamber -0f are connected in fluid communication by penetrating the support plate 3 between the oc and oc. Heat exchange area
0e includes an inlet nozzle, 21/, and an outlet nozzle for the secondary cooling phase supplied to a steam generator (not shown), and an outlet nozzle, 7! i is 6
1tj is late.

Although the swing type check valve is shown as an example, other types of check valves may be used as long as they can prevent backflow of the primary cooling control to the pump side. Also, the heat exchanger may be of the i'g pipe type. It may be in other formats instead.

With the above configuration, by energizing the pump motor JOb,' and driving the pump 3θ, the secondary cooling shrine enters the impeller part 30a via the reactor outlet pipe S, where it is pressurized. The valve body lb of check valve J, 7, which passes through 21 and is located near the opening of the passage ko/, is the first
While rotating clockwise in the figure, move to the water chamber 20f.
flows into. After that, the next cooling rate is in the second water chamber. It enters the first water volume code od through the primary coolant +lj path inside the heat transfer tube (not shown) that opens at f, and enters the first water chamber for the core, l? f17
It returns to the reactor via the reactor inlet piping connected to d. On the other hand, the neck root, 2 ob and co. The thermophilic exchange area between 0 and θ
The secondary coolant enters into e from the inlet nozzle q, passes through the outside of the heat transfer tube in the area, exchanges heat with the primary cooling refrigerant in the inner a, and is led out from the outlet nozzle II, 2j. Steam generation (not shown)) is supplied to K.

The first figure is an elevational view showing the connection relationship of the five intermediate heat exchangers θ to the reactor vessel/, and the third figure is a J-run mm sub-reactor having the above-mentioned intermediate heat exchanger-0, respectively. The floor plan is shown.

According to the present invention, the check valve is incorporated into the ice chamber of the intermediate heat exchanger separately from the pump, so the center-to-center distance between the reactor and the intermediate heat exchanger can be reduced from the conventional distance. Compared to the case where a check valve is installed in the horizontal part of the U-shaped inlet pipe, it is possible to shorten the length by about zm, which is approximately the length of the horizontal part, and therefore,
When the piping layout for absorbing the thermal expansion of the piping is taken into account, the center-to-center distance t' shown in FIG. 2 is reduced by about 3 m compared to l in FIG. 9. Therefore, the reactor containment vessels that house these reactors and intermediate heat exchangers, etc. are made as small as possible, and the outside of the reactor (there is a significant reduction in costs. It is common to have a main cooling loop, for example in the case of the J-loop type, the internal dimensions of the reactor containment vessel in Figure 3 are conventionally typically about 1Io.
m, but it has been shortened to about JOm, reducing the construction cost to about 20~. It has a remarkable effect of reducing the amount by 2j%.

In addition, since the intermediate heat exchanger is installed horizontally, it is possible to secure a sufficient head space between the intermediate heat exchanger and the center of the reactor core, which is necessary for the natural circulation of the primary coolant. It is possible to greatly improve reliability against loss accidents.

In history, by installing the pump in the water tank, the inner cylinder that was conventionally provided in the intermediate heat exchanger was eliminated, so the diameter of the intermediate heat exchanger was reduced, reducing the cost of each. can do.

[Brief explanation of the drawing]

Fig. 1 is an elevational view schematically showing an intermediate heat exchanger for a fast breeder reactor according to the present invention. Facing r, g, i
The figure is a schematic plan view of a 3-loop nuclear reactor plant including the intermediate heat exchanger shown in Figure 1, and Figure jBQ is a schematic diagram of the main cooling system of a nuclear reactor plant including a conventional pump-embedded intermediate heat exchanger. be. ,! 0...Intermediate heat exchanger, KoOd...One water chamber,)
Of...Senriki's water chamber, 2/...-Next cooling passageway, -Co...1 (stop valve, 30...-Next cooling IA circulation pump.! E1171 Deroto Mitsubishi Atomic Crab Industry Co., Ltd. Company Figure 2 Figure 4

Claims (1)

[Claims] It has two ice chambers that communicate with each other through the primary coolant passage inside the heat transfer tubes, and is stored horizontally.One of the ice chambers has a vertically installed primary cooling circulation bomb, and the other ice chamber contains the primary cooling circulation bomb. An intermediate heat exchanger for a fast breeder reactor, characterized in that a check valve for preventing backflow is incorporated in a curved state with the circulation pump via another primary coolant passage.