JPH028278B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a support device for equipment inside a LMFBR (fast breeder reactor).

Conventionally, a support device for in-core equipment in this type of nuclear reactor has a structure as shown in FIG.

In the figure, 1 is a reactor vessel, 2 is a roof slab, 3 is an intermediate heat exchanger which is an in-core equipment, 4 is a primary system pump, 5 is a core support structure, 6 is a core upper mechanism, 7 is an upper plenum, 8 9 is a lower plenum, 9 is a partition wall structure, 10 is a reactor core, and 11 is an in-core piping.

The upper core mechanism 6 is suspended from the roof slab 2, and the reactor core 10 is suspended from the reactor vessel via the core support structure 5, and the coolant leaving the core 10 flows into the high temperature upper plenum 7. , through an intermediate heat exchanger 3 to a lower temperature plenum 8. The coolant in the lower plenum 8 is sucked into the primary system pump 4 and sent into the reactor core 10 again through the reactor piping 11. Further, since the partition wall structure 9 is provided to minimize heat loss from the high temperature upper plenum 7 to the low temperature lower plenum 8, the temperature of the core support structure 5 is approximately equal to the lower plenum temperature.

The lower plenum 8 is compared to the upper plenum 7,
Although the temperature is low, there is a temperature difference of about 300°C from the upper surface of the roof slab 2, which is the installation surface for the intermediate heat exchanger 3 and the primary system pump 4.

In the above-described structure, the reactor equipment such as the intermediate heat exchanger 3, the primary system pump 4, and the core upper mechanism 6, especially the long intermediate heat exchanger 3 and the primary system pump 4, are simply suspended from the top. Cantilever beams have little prospect of being structurally viable in areas with severe seismic conditions. Therefore, conventionally, the intermediate heat exchanger 3 and the primary system pump 4 are installed in the roof slab 2, which is the installation part of the intermediate heat exchanger 3 and the primary system pump 4, and the intermediate heat exchanger 3 and the primary system pump 4 in the core support structure 5.
The manometer structure 12 was designed to be able to absorb the difference in thermal expansion displacement caused by the temperature difference with the penetrating portion, and also to provide some support effect at the lower part of the intermediate heat exchanger 3 and the primary system pump 4.

FIG. 2 is a detailed view of the manometer structure 12. If the intermediate heat exchanger 3 moves in the direction of the arrow () relative to the partition cylinder 13, then the The gap in the ' direction becomes smaller, and the gap in the X direction becomes larger.

Moreover, since the intermediate heat exchanger 3 and the outer cylindrical body 14 have an integral structure, the gaps between the partition cylinder 13 and the outer cylindrical body 14 are reversed. Therefore, the fluid in the gap between the intermediate heat exchanger 3, the partition cylinder 13, and the outer cylinder 14 moves in the direction of the arrow (→), and the energy for the movement of the fluid acts as a drag force on the intermediate heat exchanger 3. It is expected to have a damping effect over time.

However, in the above-mentioned system, the gaps between the intermediate heat exchanger 3 and the partition cylinder 13, and between the partition cylinder 13 and the outer cylinder 14 are determined by the manufacturing and installation accuracy of the intermediate heat exchanger 3 and the above-mentioned installation part of the intermediate heat exchanger 3. Considering the thermal expansion displacement caused by the temperature difference in the penetrating portion of the core support structure 5, it is thought that about 100 mm is required for each gap, so the flow path area is large and a significant vibration damping effect cannot be expected.

In addition, when an earthquake occurs, liquid sodium between the partition cylinder 13 and the outer cylinder 14 passes over the upper end of the partition cylinder 13 and enters the gap between the intermediate heat exchanger 3 and the partition cylinder 13, except for the flow path where it goes around. In order to prevent a flow path from occurring, a He gas layer 16 is provided at the top, and there are problems such as a system for controlling the pressure of the He gas layer 16 outside the furnace and an introduction pipe 15 outside the furnace. Ta.

Therefore, in order to avoid the conventional lower steady rest structure mentioned above, it is possible to increase the thickness of the furnace equipment and increase its rigidity. It is difficult to make it structurally viable due to thermal stress caused by changes in temperature.

In addition, in the manometer structure, a He gas pressure control device is required, and there is also an inlet pipe 15 inside the furnace.
However, since the damping effect is relatively small, it has been desired to develop a new structure to replace these conventional structures.

The present invention has been made in response to the above-mentioned needs, and is designed to be used as a structure for supporting equipment inside a nuclear reactor vessel, without generating drag against gradual thermal displacement in the radial direction, and without generating resistance against sudden thermal displacement during earthquakes. As a support device that generates a large resistance against vibrations, a ring assembly consisting of a steady rest ring and a receiving ring is installed in multiple stages, and the escape of fluid is blocked in order to enhance the fluid vibration effect. According to the invention of No. 1, one set or several sets of the above-mentioned ring combinations are provided on the upper and lower sides, four or more vertical vanes are installed at equal positions in the circumferential direction between the above-mentioned upper and lower ring combinations, and the fluid vibration It is an object of the present invention to provide a support device for equipment in a reactor according to the second invention, in which escape of fluid is sealed in order to enhance the effect.

Embodiments according to the present invention will be described below with reference to FIGS. 3 to 7.
This will be explained in detail based on the figures.

FIGS. 3 to 4 a and b show the first embodiment according to the present invention.
This is a specific example of an in-core equipment support device showing an embodiment of the invention, and the left and right sides of FIG.
The same parts corresponding to the conventional structure will be described with the same reference numerals.

In the figure, 17 is a stand pipe for the intermediate heat exchanger 3 which is a furnace equipment, 18 is a steady rest ring, 19 is a receiving ring for the steady rest ring 18, 1
9', 19'' are fixed receiving rings.

Here, an appropriate amount of gap δ ₁ (approximately 5 mm) is provided between the intermediate heat exchanger 3 and the steady rest ring 18 so as not to restrict the difference in thermal expansion between the two, and a gap δ 1 (approximately 5 mm) is provided between the steady rest ring 18 and the stand pipe 1.
7, and a gap δ ₂ (approximately 50 mm) is provided between the receiving ring 19 and the intermediate heat exchanger 3. This is caused by the difference in thermal expansion between the roof slab 2 and the core support structure 5, which causes the intermediate heat exchanger 3 to
is relatively displaced in the direction of the arrow (), but this is to prevent it from being constrained.

The steady rest ring 18 and the receiving ring 19 are provided in multiple stages with different diameters, and are made of a different material from the intermediate heat exchanger 3 and the stand pipe 17. In the embodiment according to the present invention, the intermediate heat exchanger 3, stand pipe 17, fixing rings 19', 19'', etc. are made of austenitic stainless steel SUS304, while the steady rest ring 18 and the receiving ring 19 are made of SUS304. Martensitic stainless steel SUS403 with a low coefficient of thermal expansion is used.

Furthermore, the outer periphery of the steady rest ring 18 and the inner periphery of the receiving ring 19 are provided with irregularities to increase resistance when fluid circulates, as shown in FIG. 4a.

In addition, as shown in FIG. 4b, instead of the unevenness, a large number of wing-shaped protrusions 18', 19'' or a labyrinth structure may be used. In other words, in FIG. 4b, the protrusions 18' are attached to the steady rest ring 18. , is an example in which the protrusion 19 is protruded from the stand pipe 17, and shows a horizontal cross section at the position of the steady rest ring 18.
The inner surface of the receiving ring 19 is hidden.

In addition, the steady rest ring 18, the receiving ring 1
The sliding surface of No. 9 is surface hardened with chromium carbide or the like to prevent seizure or the like.

Note that the steady rest ring 18 may be inserted into the outer periphery of the intermediate heat exchanger 3, and the receiving ring 19 may be inserted into the inner periphery of the stand pipe 17, but the receiving ring 19 may be fixed to the stand pipe by welding or screwing. You may do so. In this case, the load applied to the upper and lower fixing rings 19', 19'' is reduced, which is advantageous in terms of structure.

5 and 6 are longitudinal and transverse sectional views showing an embodiment of the second invention according to the present invention, and FIG. 7 is an exploded perspective view showing the main parts of the same, including a steady rest ring, It has a structure in which a ring assembly of rings 19 is arranged above and below a support part, and four vanes 20 are vertically arranged equally in the circumferential direction between them.

The vane 20 is held between groove-shaped frames 22 integrally provided on the stand pipe 17 with an appropriate gap therebetween, and is pressed inward by a leaf spring 21.

Therefore, in conjunction with the movement of the intermediate heat exchanger 3, the vanes 20 are structured to be able to move freely by a gap δ ₂ only in the radial direction.

In addition, as shown in FIG. 7, in order to prevent the vanes 20 from falling off when the intermediate heat exchanger 3 is pulled out, the installation width l ₁ of the leaf spring 21 of the vane 20 is the width of the vane insertion part of the frame 22. Formed wider than l ₂ . Further, the sliding surface of the vane 20 is subjected to a predetermined surface hardening treatment to prevent seizure. In the figure, numerals 23 and 24 are annulance parts.

As explained in detail above, according to the support device for furnace equipment of the present invention, the intermediate heat exchanger 3 can be rested with a smaller gap without being constrained by thermal expansion when the liquid temperature rises. .

Further, in the event of an earthquake, the liquid around the intermediate heat exchanger 3 tends to rapidly move in the circumferential direction and the vertical direction as the intermediate heat exchanger 3 swings. At this time, its movement in the vertical direction is extremely restricted by the steady rest ring, the receiving ring, and the fixing ring, resulting in a remarkable vibration damping effect.

Incidentally, when comparing the difference in damping effect between the case where the He gas layer has an open end as shown in Fig. 2 and the case where it is almost sealed as shown in Fig. 3, it is found that in the moment load generated in the intermediate heat exchanger 3, In the case shown in Fig. 2, it decreases to about 80% of that in Fig. 2. Furthermore, the unevenness of the steady rest ring and the receiving ring helps to limit the circulation of liquid in the circumferential direction, making it possible to further enhance the vibration damping effect.

Particularly, according to the second aspect of the present invention, the fluid vibration effect is enhanced by substantially sealing the upper and lower sides and blocking the flow of liquid circulating in the circumferential direction with vanes.

In other words, when the intermediate heat exchanger tries to rapidly move in the direction of the arrow () in FIG. 6, the movement of the fluid in the annulus is blocked by the vane, so
Pressure Po is generated on one side, and negative pressure is generated on the other side.
This pressure difference creates a large drag force that can restrict movement of the intermediate heat exchanger 3.

Note that for gentle displacements such as thermal displacements, the fluid is not completely sealed, so the speed is not restricted.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing a conventional furnace equipment support device, FIGS. 2 a and b are cross-sectional views and vertical cross-sectional views showing a conventional manometer structure, and FIG. FIGS. 4a and 4b are cross-sectional views showing essential parts of the in-furnace equipment support device according to an embodiment of the present invention. FIGS. FIG. 7 is an exploded perspective view showing the main part of FIG. 5. FIG. 1... Reactor vessel, 3... Intermediate heat exchanger, 17
...stand pipe, 18...steady ring,
19... Reception ring, 19', 19''... Fixing ring, 18', 19... Wing-shaped projection, 20... Vane, 21... Leaf spring, 22... Frame body.

Claims (1)

[Claims] 1. In an earthquake-resistant support structure for equipment inside a nuclear reactor, a ring assembly consisting of a steady ring and a receiving ring is installed in multiple stages between a supported body and a stand pipe provided on the outside thereof, A support device for equipment inside a furnace, characterized in that its top and bottom are sealed with a fixing ring fixed to a standpipe. 2. The support device for furnace equipment according to claim 1, wherein the receiving ring is fixed to the stand pipe by welding or screwing. 3. The device for supporting equipment in a furnace according to claim 1, wherein the ring assembly is made of a material that is the same as the material of the supported body. 4. The support device for furnace equipment according to claim 1, wherein the outer periphery of the steady rest ring and the inner periphery of the receiving ring have irregularities. 5. The support device for furnace equipment according to claim 1, wherein the outer periphery of the steady rest ring and the inner periphery of the stand pipe facing the outer periphery have a wing-like projection or a labyrinth structure. 6. In the seismic support structure for internal reactor equipment, at least one ring assembly consisting of a steady rest ring and a receiving ring is installed at the upper and lower positions between the supported body and the stand pipe provided on the outside thereof, A support device for in-furnace equipment, characterized in that four or more vertical vanes are installed at equal positions in the circumferential direction between the ring combinations in the above-mentioned upper and lower positions. 7. The device for supporting equipment in a furnace according to claim 6, wherein the material of the ring combination is the same as the material of the supported body.