JPS6093994A - 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 provides a wet motor pump built into a nuclear reactor in a nuclear power plant! The present invention relates to a cooling heat exchanger, and particularly to improvements in its support structure.

[Technical background of the invention]

In a boiling water nuclear power plant that uses a wet motor ponzo built into the reactor (hereinafter referred to as an internal pump) to circulate core cooling water, the wet motor ponzo that is the drive source of this internal pumper is A heat exchanger is provided to circulate cooling water to cool the motor.

Figures 1 and 2 show a conventional heat exchanger 4klk, in which a reactor pressure vessel 1 in which a reactor core is formed has a plurality of legs protruding from its outer circumferential surface. The part 2 is installed and supported by a protrusion 4 provided around the inner peripheral surface of the reactor pressure vessel foundation 3. A casing 7 of an internal pump 766 is installed vertically on the lower end plate 5 of the reactor pressure vessel 1, and an impeller (not shown) facing into the reactor pressure vessel 1 is rotatably driven inside the casing 7. A wet motor (not shown) is housed therein.

On the other hand, a support pedestal 8 is protruded from the reactor pressure vessel foundation 3, and a heat exchanger 9 for the internal pump 6 is fixed to the support pedestal 8. This heat exchanger 9 is arranged so as to face the vicinity of the internal pump 6, and a pair of upper and lower cooling water pipes 1 are disposed between the heat exchanger 9 and the casing 7 of the internal pump 6.
0.11 is allocated.

According to the above-described configuration, the rotation of the auxiliary impeller provided in the wet motor causes the cooling water to flow through the heat exchanger 9, the lower cooling water pipe 11, the casing 7 of the internal pump 6, the upper cooling water pipe 10, circulates in the order of heat exchanger 9,
By supplying the cooling water cooled in the heat exchanger 9 into the pump casing 7, the internal pump 7°
pump casing 7 due to heat generated by the wet motor itself and heat input from the reactor pressure vessel 1 due to the drive of pump casing 6;
It is possible to suppress the temperature rise inside the wet motor and prevent damage to the wet motor.

Note that when the wet motor is stopped, the cooling water is circulated due to the temperature difference of the cooling water in the pump casing 7, so both the cooling water pipes 10 and 11 are arranged so as to enable this circulation of the cooling water. , and heat exchanger 9
is installed at a higher position than the pump casing 7.

[Problems with background technology]

By the way, during normal operation of the reactor, inside the reactor pressure vessel 1, reactor coolant at about 280°C is circulated by the drive of the internal pump 6, and the reactor coolant at about 280° C. The ambient air temperature inside 3 is maintained at about 60°C. Therefore, due to the temperature inside the reactor pressure vessel 1, the reactor pressure vessel 1 below the part 2 is stretched downward and radially outward due to thermal expansion. The pump casing 7, which is vertically installed at the pump 1, also descends diagonally downward.

On the other hand, the pump casing 7 and a pair of cooling water pipes 10
．． The heat exchanger 9 connected to the reactor pressure vessel foundation 3 by the heat exchanger 9 is directly fixed to the support pedestal 8 protruding from the reactor pressure vessel foundation 3. The spacing between the vessels 9 is increased and therefore both cooling water pipes 10.
11, tensile stress is generated.

In order to reduce such tensile stress and thermal stress caused by heat in the reactor pressure vessel 1, and to ensure the integrity of the cooling water piping 10, 11, the pump casing 7 has conventionally been rounded, as shown in detail in FIG. The vertical and horizontal distances between the heat exchangers 9 and the heat exchangers 9 were increased, and the cooling water pipes 10 and 11 were arranged to have sufficient pipe lengths and bends. For this reason, the cooling water piping 1 is installed in the limited space below the reactor pressure vessel 1.
The length of 0.11 was longer, and the large number of curved parts made many pipe welding operations complicated, and the maintenance and inspection time for cooling water piping 10.11 was also long. . Furthermore, because the distance between the pump casing 7 and the heat exchanger 9 was large and the length of the cooling water piping 10.11 was long, there was a problem that the natural circulation of cooling water was not efficient when the wet motor was stopped. there were.

(4) [Object of the Invention] In view of the above-mentioned points, the present invention reduces the occurrence of stress in the cooling water piping due to changes in the relative position between the pump casing and the heat exchanger, and also eliminates the need for welding the piping. It is an object of the present invention to provide a heat exchanger that can be easily maintained and inspected.

[Summary of the invention]

In the present invention, a support member is attached to a heat exchanger for an internal pump, and a buffer means such as a spring or a damper 2 is interposed between the support member and the reactor pressure vessel foundation or support frame. .

[Embodiments of the invention]

The present invention will be explained below with reference to embodiments shown in the drawings. Note that the same components as those of the conventional device described above are denoted by the same reference numerals in the drawings, and the explanation thereof will be omitted.

3 and 4 show a first embodiment of the present invention, in which two upper and lower support frames 8.8 projecting from the reactor pressure vessel foundation 3 each support a heat exchanger 9'ft: It has a frame 12 (FIG. 4) formed so that it can be inserted therethrough.

On the other hand, a pair of annular support members 13 and 13 are fitted onto the outer peripheral surface of the heat exchanger 9 so as to be positioned above each support frame 8. , four through holes 14 and 15 are formed at mutually corresponding positions with an interval of 90 degrees between each.

Then, a bolt 16 is inserted from the through hole 14 of each support member 130 to the through hole 15 of each frame 12, and each y1? The end of the root 16 is prevented from being pulled out by a nut 17.
Further, in the present invention, in particular, a coil spring 18 is wound around the outer periphery of each port 16 so as to be interposed between the support member 13 and the frame body 12.

According to the above-described configuration, since the plurality of coil springs 18 are interposed between the support member 13 of the heat exchanger 9 and the support frame 8, the heat exchanger 9 can move in the vertical direction with respect to the support frame 8. This means that it is supported as such. therefore,
When the pump casing 7 is displaced downward due to the rise in temperature inside the reactor pressure vessel 1, the heat exchanger 9 can also be lowered following the lowering of the pump casing 7. Stress in the pair of cooling water pipes 10 and 11 connecting the exchangers 9 can be reduced. For this reason, the cooling water pipes 10.11 have a larger margin for thermal stress, and can be arranged with a reduced pipe length and bends.

In addition, as shown in FIG. 3, the through hole 15f of the support frame 8
:& By making the diameter larger than the outer diameter of seat 16,
The heat exchanger 9 can also be made movable in the horizontal direction.

FIG. 5 shows a second embodiment of the invention, which is similar to the first embodiment described above. In this case, the coil spring 19, which is interposed between the support member 13 of the heat exchanger 9 and the support frame 8, is wound around the heat exchanger 9, without providing the seat 16.

Such a configuration can also provide the same effects as those of the first embodiment.

FIG. 6 shows a third embodiment of the present invention, in which a plurality of arms n each provided with a damper 21 are attached to the step (7) below the protrusion 4 of the reactor pressure vessel foundation 3.
The lower end of each arm n is connected to the support member 13 of the heat exchanger 9.

Even with such a configuration, the heat exchanger 9 can be moved up and down by the action of each damper 21, so that the cooling water pipes 10.
11 stress is reduced.

7 and 8 show modifications of the embodiments shown in FIGS. 3 and 5, respectively, in which the support member 13
The relative positions of the support frame 8 in the vertical direction are reversed. The force and other configurations are the same as in FIGS. 3 and 5.

FIG. 9 shows still another embodiment of the present invention, sb,
Between the support member 13 of the heat exchanger 9 and the support frame 8
A plurality of arms n equipped with dampers 21 similar to those shown in the figure are arranged in series.

With such a configuration as well, the same effects as the embodiment shown in FIG. 6 can be achieved.

〔Effect of the invention〕

As explained above, the heat exchanger according to the present invention is equipped with a support member, and a buffer means is interposed between the support member and the reactor (8) pressure vessel foundation or support frame. The buffer absorbs the relative displacement between the internal pump casing and the heat exchanger due to thermal expansion, reducing stress in the cooling water piping and simplifying piping welding and maintenance inspection. It has excellent effects.

[Brief explanation of the drawing]

FIG. 1 is a front view showing a conventional heat exchanger, FIG. 2 is a plan view of FIG. 1, FIG. 3 is a front view showing an embodiment of the heat exchanger according to the present invention, and FIG. Plan view of figure, figure 5, figure 6,
FIG. 7, FIG. 8, and FIG. 9 are front views showing other embodiments of the present invention. 1...Reactor pressure vessel, discharge...Reactor pressure vessel basics,
6... Nuclear reactor built-in wet motor Denzo (internal pump), 7... Pump casing, 8... Support frame, 9... Heat exchanger, to, ii... Cooling water piping, 13...Support member, 16.19...Coil spring, 21...Dan/JO Applicant's representative Kiyoshi Inomata (11) Kutsu 7 ■ h9 Figure

Claims (1)

[Scope of Claims] 1) A support member is attached to a heat exchanger that is connected to a wet motor dump in a reactor arbor via cooling water piping and supported by a support frame that projects from the reactor pressure vessel foundation. A heat exchanger characterized in that a buffer means is interposed between the support member and the foundation or support frame. 2) The heat exchanger according to claim 1, wherein the buffer means is a coil spring. 3) The heat exchanger according to claim 1, wherein the buffer means is a damper.