JPH02190795A - Partition wall of tank type fast breeder - Google Patents

Abstract

PURPOSE:To reduce the stress of the partition wall by clamping the free end part of the inside flange of a partition wall small barrel slidably and interposing spacers in the annular gap between the small barrel and a stand pipe and external barrel of the partition wall, and a gas dam wall. CONSTITUTION:A short-period load due to a sodium flow, an earth quake, etc., as to a horizontal load placed on the partition wall small barrel 15 and partition wall external barrel 19 is reduced by sodium in annular gap A and B to attenuate the vibration of the external small barrel 15 and external barrel 19. The fluid attenuation effect of the sodium becomes more effective because the sodium is inhibited from flowing by the respective spacers 20a-20d in the gaps A and B. Further, the gaps A and B are formed to wide area of the small barrel 15 and external barrel 19, so the load placed on those gaps A and B are placed almost equally on the wide area and excessive stress is prevented from being generated locally on the small barrel 15 and outer barrel 19 of a thin plate. The small barrel 15 is held at both end parts of a core support tank 12 horizontally slidably to prevent restraint stress due to heat expansion from being generated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a bulkhead for a liquid metal cooled tank-type fast breeder reactor, and more particularly to an improvement in the support structure of the bulkhead.

(Prior Art) Conventionally, this type of tank-type fast breeder reactor has a reactor vessel 1 containing a reactor core 1 loaded with nuclear fuel, as shown in FIG. 5, for example.
ff2 is built-in in a state immersed in a liquid metal coolant such as Na, and this core I! A plurality of cylindrical stand pipes 3 are arranged on the outer periphery of 2 at a required pitch in the circumferential direction.

A cylindrical bulkhead shell 4 is coaxially fitted onto the outer periphery of each standpipe 3 with a required gap in the radial direction, and the lower end of each bulkhead half shell 4 on the core barrel 2 side Inner flanges 4a are integrally formed, and each inner flange 4a is fixed by welding or the like onto the upper surface of a core support structure 5 that supports the load of the core barrel 2.

On the other hand, on the inside of the gas dam wall 6 attached to the inner peripheral surface of the reactor vessel 1 over the entire circumference, a partition wall outer shell 7 is provided with a required gap.
is attached to the entire inner circumference of the gas dam wall 6, and the bottom of the partition outer shell 7 is connected to the outer circumferential bottom of the partition half shell 4 facing the partition outer shell 7.

The partition half-shell 4 and the inner flange 4a partition a hot plenum 8 into which high-temperature sodium flows into a cold plenum 9 into which low-temperature sodium flows, so that high-temperature sodium and low-temperature sodium do not mix.

(Problem to be Solved by the Invention) However, such conventional partition walls, that is, the partition half shell 4, the inner flange 4a, and the partition outer shell 7, do not reduce the thermal stress caused by the temperature difference in the thickness direction that occurs in these partition walls. , and in order to reduce the amount of material, the thickness of the plate is 20 to 30#I, so that only the lower end of the inner flange 4a is fixed on the core support structure 5, as shown in FIG. In this case, there is a problem in that excessive stress is generated in the partition wall due to earthquakes, sodium flow, etc.

In addition, when the bulkhead outer shell 7 is fixed in the same way as the bulkhead half shell 4 in order to reduce stress on the partition wall due to earthquakes, sodium flow, etc., the difference in thermal expansion between the bulkhead half shell 4 and the bulkhead outer shell 7 is Since the partition wall is restrained, the thermal stress generated in the partition wall becomes excessive.

Furthermore, when the structure of the member for fixing the partition wall outer shell 7 is a thin plate structure, there is a problem in that excessive stress is generated locally.

Therefore, the present invention has been made in consideration of the above circumstances, and
The purpose is to provide a partition wall for a tank-type fast breeder reactor that can reduce stress on the partition wall even when loads are applied to the partition wall due to earthquakes, sodium flow, thermal expansion differences, etc.

[Structure of the invention]

(Means for Solving the Problems) The present invention has been made to solve the above problems, and is configured as follows.

In other words, the present invention provides a structure in which a plurality of standpipes are arranged at a predetermined pitch in the circumferential direction on the outer circumference of a core tank built in a nuclear reactor vessel, and each of the standpipes is provided at a predetermined interval in the radial direction. A tank-type high-speed tank having each partition half-shell to be fitted, and a partition outer shell attached at a required interval in the radial direction inside the gas dam wall attached to the inner circumferential surface of the reactor vessel. In the bulkhead of the breeder reactor, the free ends of the inner flanges provided on the core barrel side of each bulkhead half are vertically sandwiched by the upper end of the core barrel so as to be slidable in the radial direction. The outer end of an outer flange provided on the gas dam wall side at the upper end of the wall outer shell is fixed to the upper end of the gas dam wall, and an annular gap between each of the stand pipes and each of the partition half-shells, as well as the partition wall is fixed to the upper end of the gas dam wall. The gas dam is characterized in that spacers are provided at the upper and lower portions of the annular gaps between the outer shell and the gas dam wall, respectively, to suppress the flow of fluid interposed in these annular gaps.

(Function) Of the horizontal loads applied to the bulkhead half-wall and bulkhead shell, short-term loads due to earthquakes, thorium flow, etc. are applied to the annular gap between the bulkhead half-shell and the standpipe, and between the bulkhead shell and the gas dam wall. The vibration damping effect of the fluid interposed in the annular gap between the two is received.

Therefore, the load on these partition walls is evenly distributed over a wide area of the partition wall, and it is possible to prevent excessive stress from being locally generated in the partition wall having a thin plate structure.

In addition to the horizontal load applied to the bulkhead, long-term loads due to differences in thermal expansion are borne by the gas dam wall and the standpipe via spacers provided at the upper ends of the bulkhead outer shell and the bulkhead half shell.

For this reason, it is possible to prevent the bulkhead from shaking in the horizontal direction, and since the axial dimensions of the bulkhead outer shell, gas dam wall, bulkhead half shell, and stand pipe are large, they can absorb thermal expansion differences over a wide range and It is possible to prevent the occurrence of severe thermal stress.

Furthermore, the free end of the inner flange of each bulkhead half-shell is supported by the upper end of the core barrel so that it can freely slide in the radial direction (horizontal direction), and the difference in thermal expansion is not constrained. It is possible to prevent thermal stress from occurring.

The vertical load applied to the bulkhead is distributed to the gas dam wall, which fixes the outer flange of the bulkhead outer shell, and the upper end of the core barrel, which supports the inner flange of the bulkhead half shell so as to be slidable in the radial direction. Therefore, it is possible to prevent excessive vertical stress from being generated in the partition wall having a thin plate structure.

(Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 to 4.

FIG. 1 is a longitudinal sectional view of the main part of this embodiment, and in the figure,
A reactor vessel 11 houses a reactor core tank 12 immersed in a liquid metal coolant such as Na. ! 12 is fixed on a core support structure 13.

For example, four cylindrical stand vibes 14 are arranged at a required pitch in the circumferential direction on the outer periphery of the core tank 12 in the reactor vessel 11, and the lower end of each stand vibe 14 bulges out into a spherical shape. It is fixed to the core support structure 13 and the inner peripheral wall of the reactor vessel 11.

A cylindrical bulkhead half body 15 is coaxially fitted onto the outer periphery of each stand vibe 14 with a required annular gap in the radial direction, and the lower end of each bulkhead half body 15 on the core barrel 12 side is An inner flange 16 extending toward the core barrel 12 side is integrally provided in a protruding manner.

The free end (tip) of each inner flange 16 is connected to the core barrel 1.
The small partition wall 1ji15 is held between the upper and lower sides by the upper end flange 12a of the 2 and the presser plate 17 so as to be slidable in the radial direction, so that the small partition wall 1ji15 can be displaced in the radial direction.

That is, as shown in FIGS. 2(A) and 2(B), the core barrel 12 has a sliding groove 12b with an opening on the top surface cut out on the soil surface of the upper end flange 12a, and the F of this sliding groove 12b is cut out. This sliding FM 12 is closed by a flat presser plate 17.
Insert the tip of the inner flange 16 into the inner flange 16 in the radial direction (see Fig. 2).
In B), it is slidably inserted in the direction of the arrow).

On the other hand, between the inner circumferential surface of the reactor vessel 11 and the stand vibrator 14, a gas dam wall 18 and a bulkhead outer shell 19 are respectively attached along the entire circumference of the reactor vessel 11. An annular gap B is set between the outer peripheral surface of the gas dam wall 18 and the gas dam wall 18 .

Further, the bottom of this outer partition 1119 is radially connected to the bottom of the outer periphery of the partition half-shell 15.

Further, annular upper and lower spacers 20a are provided around the outer periphery of the stand vibe 14 at portions corresponding to the upper and lower ends of each partition half body 15, respectively.

20b are provided in a protruding manner to suppress the flow of sodium in the annular gap A between the partition wall half body 15 and the stand vibe 14 in the axial direction (in the vertical direction in FIG. Vibration in the radial direction of the shell 15 is suppressed.

Note that the outer end portion of the lower spacer 20b is fitted into the hook-shaped engaging portion 21 of the partition wall half body 15.

On the other hand, upper and lower spacers 20c and 20d are provided at the upper and lower ends of the annular gap B to suppress the vertical flow of the 1-lium interposed in the annular gap B to the gas dam wall 18. At the upper end of the gas dam wall 18, as shown in FIG. It is fixed. In addition, No. 11 ¥1
Inside, numeral 23 is a high temperature plenum, and 24 is a low temperature plenum.

Next, the operation of this embodiment will be explained.

Of the horizontal loads applied to each bulkhead half shell 15... and the bulkhead outer shell 19, short-term loads due to earthquakes and Natori 1Kum flow are buffered and supported by the sodium in the annular gaps A and B, and the bulkhead small 1ji15 And the vibration of the partition wall outer shell 19 is suppressed.

This fluid vibration effect due to sodium is caused by each annular gap A, B.
Since the flow of sodium is suppressed by each of the spacers 20a to 20d, a negative layer effect is achieved.

In addition, since each annular gap A, 8 is formed by a wide area of the partition wall half shell 15 and the partition wall outer shell 19, the load applied to these annular gaps A, B is almost equally distributed over this wide area, It is possible to prevent excessive stress from being locally generated in the thin partition wall half shell 15 and the partition wall outer shell 19.

In addition, the bulkhead half-shell 15 is held between the upper and lower ends of the core support tank 12 by inner flanges 16 so that it can move freely in the horizontal direction, and can be freely displaced in the horizontal direction. It is possible to prevent the generation of restraint stress due to differences, etc.

Of the horizontal loads applied to the bulkhead half shell 15 and the bulkhead outer shell 19, the vertical load due to the difference in thermal expansion is applied to the gas dam wall 18 and stand pipe 14 via the spacer 20a. 15 and the partition wall outer shell 19 can be prevented from shaking in the horizontal direction (radial direction).

Furthermore, the bulkhead half body 15, the stand pipe 14, the ra
Since the axial dimensions of the outer wall shell 19 and the gas dam wall 18 are large, the difference in thermal expansion between them is widely absorbed within the range of these axial dimensions, making it possible to prevent excessive thermal stress from occurring.

Since the vertical load on the bulkhead half body 15 and the bulkhead outer body 19 is supported by two locations, the outer flange 19a and the inner flange 16, the bulkhead with a thin plate structure is more effective than the case where both the inner and outer sides are supported at one location. can significantly reduce stress.

In addition, in the spinning example, the upper and lower spacers 2Qa, 2
Although the case where the spacers 2Qa and 20b are fixed to the outer circumference of the stand pipe 14 has been described, these spacers 2Qa and 20b may be provided on the inner circumferential surface of the partition wall half body 15.

Furthermore, although the case where the spacers 20C and 20d are fixed to the gas dam wall 18 has been described, the spacers 20c and 20d are
20d may be provided on the partition wall outer shell 19.

〔Effect of the invention〕

As explained above, the present invention is fixed at two locations: the inner flange of each bulkhead half body and the outer flange of the bulkhead outer body, so it is possible to significantly reduce the stress generated in each bulkhead of the thin plate structure. In addition, since the free end of the inner flange is slidably supported in the radial direction at the upper end of the core barrel, and differences in thermal expansion are not restricted, local excessive stress can be prevented from occurring.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a main part of an embodiment of the present invention, and FIG. 2 (A
>, (B) is an enlarged plan view of the Ti part in Fig. 1, an enlarged view of the ■ part,
3 is an enlarged view of section m shown in FIG. 1, FIG. 4 is an enlarged view of section ``■'' in FIG. 1, and FIG. 5 is a partially enlarged vertical sectional view of the conventional example. 11... Reactor vessel, 12... Core tank, 13...
Core support structure, 14...stand pipe, 15...
・Partition half shell, 16...inner flange, 18...gas dam wall, 19-1id wall outer shell 1, 20a, 20b, 20
c, 20d...Spacer. Representative Patent Attorney Noriyuki Ken Yudo Ken Maru

Claims (1)

[Claims] On the outer periphery of a plurality of standpipes arranged at a required pitch in the circumferential direction on the outer periphery of the core tank built into the reactor vessel,
Each of the small bulkheads is fitted on the outside at a required interval in the radial direction, and the gas dam wall is attached at a required interval in the radial direction inside the gas dam wall attached to the inner peripheral surface of the reactor vessel. In a bulkhead of a tank-type fast breeder reactor having a bulkhead outer shell, the free ends of the inner flanges provided on the core barrel side of each bulkhead small shell are slid radially onto the upper end of the core barrel. While being freely clamped in the vertical direction, the outer end of an outer flange provided on the gas dam wall side at the upper end of the outer shell of the partition wall is fixed to the upper end of the gas dam wall, so that each of the stand pipes and each of the partition walls The annular gap with the small body and the annular gap between the outer shell of the partition wall and the gas dam wall are each provided with a spacer at the upper and lower part thereof, respectively, for suppressing the flow of fluid interposed in these annular gaps. A bulkhead of a tank-type fast breeder reactor.