JPS61228394A - Intermediate heat exchanger for tank type fast breeder reactor - 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 invention] The present invention relates to an intermediate heat exchanger for a tank-type fast breeder reactor.

[Technical background of the invention and its problems] Usually, tank-type fast breeder reactors are equipped with an intermediate heat exchanger to isolate and protect the primary circuit including the reactor' from leakage accidents in the piping of the steam generator. It is installed inside the reactor vessel. Such an intermediate heat exchanger for a fast breeder reactor will be explained with reference to FIG. 2. Figure 2.

A roof slab (not shown) is installed at the upper opening of the reactor vessel 20, and the intermediate heat exchanger 22 is suspended and supported within the reactor vessel 20 by this roof slab.
is installed between the inner wall of this container '20 and the furnace wall fluid system mounting wall 21. The intermediate heat exchanger 22 includes a main body shell 23, a heat transfer tube bundle 24 installed in the main body shell 23, and an upper tube plate 25 and a lower tube plate 2 to which the heat transfer tube bundle 24 is fixed.
6, and a downcomer pipe 21 provided in the central part of the main body shell 23.
and a riser pipe 28. Under normal conditions, the high temperature primary sodium of the hot blemish flows into the main body 1123 from the intermediate heat exchanger flow hole 29, descends inside the heat transfer tube, exchanges heat with the secondary sodium, and then passes through the intermediate heat exchanger. The primary sodium exits 30 to the cold blenheim. On the other hand, the low-temperature secondary sodium descends in the downcomer pipe 27 and then rises in the intermediate heat exchanger body shell 23. A tube bundle support plate 31 is provided within the main body shell 23 to ensure uniform flow of secondary sodium. After heat exchange, the high temperature secondary sodium rises in the riser pipe 28 and flows into the secondary system loop. A partition wall 32 and a heat shield plate 33 are provided at the boundary between the hot and cold blenheims to prevent the heat of the hot blenheim from directly transferring to the cold blenheim. In addition, the main body trunk 23
As shown in the figure, a bellows 34 is provided between the lower end of the partition wall 32 and the lower end of the partition wall 32 for sealing.

By the way, when the decay heat is removed, the flow of secondary sodium stops. At this time, the primary sodium enters the main body shell 23 through the intermediate heat exchanger flow hole 29, exchanges heat with the cooling pipe 35 that acts during decay heat removal, becomes low temperature, descends inside the heat transfer tube, and is heated to intermediate heat. The primary sodium outlet 30 of the exchanger is configured to flow into the cold blenheim. In this way, during decay heat removal, low-temperature primary sodium flows into the heat transfer tubes, but since the heat of the hot brenum is directly transmitted into the main body shell 23 of the intermediate heat exchanger, the temperature on the downcomer tube 27 side of the heat transfer tube bundle 24 decreases. A radial temperature difference distribution occurs within the main body shell 23 such that the temperature on the shell wall side is low and the temperature on the shell wall side is high. As a result, the heat exchanger tube on the downcomer pipe 27 side receives the tensile force,
In addition, the heat exchanger tubes on the shell wall side are subjected to compressive force, and there is a risk that the heat exchanger tubes on the shell wall side may buckle.

[Object of the Invention] The present invention has been made in view of the above circumstances, and its purpose is to provide a tank-type structure that prevents the heat of the hot brenum from directly transmitting to the inside and prevents buckling of the heat transfer tubes. An object of the present invention is to provide an intermediate heat exchanger for a fast breeder reactor.

[Summary of the Invention] In order to achieve the above object, the present invention provides an intermediate heat exchanger for a tank-type fast breeder reactor, which is suspended and supported within the reactor vessel by a roof slab provided at the upper opening of the reactor vessel. In the intermediate heat exchanger, a plurality of heat transfer tubes supported by an upper tube plate and a lower tube plate are provided in the main body shell of the intermediate heat exchanger, and their upper ends are fixed above the upper tube plate outside the main body shell. and a skirt whose lower end is located below the heat exchanger tube bundle, and between the skirt and the main body trunk, the upper end and the lower end thereof are located near the upper end and the lower end of the heat exchanger tubes, respectively, and the main body trunk A partition wall having a surrounding cylindrical partition wall portion is provided, and an inert gas is further sealed in a space formed by the main body trunk and the skirt. At least one ring is provided on the inner surface of the partition wall cylindrical portion facing the main body cylinder, and has a gap between the ring and the main body cylinder. Further, the inert gas is injected from a pipe provided in the skirt.

[Embodiments of the invention] An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention.

In the figure, a roof slab (not shown) is installed at the upper opening of the reactor vessel 14, and the intermediate heat exchanger 1, which is suspended and supported within the reactor vessel 14 by this roof slab, is attached to the reactor vessel 14. It is installed between the inner wall and the furnace wall fluid system installation wall 15. The intermediate heat exchanger 1 includes a main body body 2, a heat exchanger tube bundle 3 installed in the main body body 2, an upper tube sheet 4 and a lower tube sheet 5 that fix the heat exchanger tube bundle 3, and a main body WA2. It is composed of a descending pipe 6 and a rising pipe 7 provided in the central part. Under normal conditions, high-temperature primary sodium from the hot blenheim flows into the main body shell 2 through the intermediate heat exchanger flow hole 8, descends inside the heat transfer tube, exchanges heat with the secondary sodium, and enters the intermediate heat exchanger 1. Sodium outlet 9
It spills into Cold Blenheim. On the other hand, the low-temperature secondary sodium descends in the downcomer pipe 6 and then rises in the main body shell 2 of the intermediate heat exchanger 1. A tube bundle support plate 10 is provided within the main body shell 2 to ensure uniform flow of secondary sodium. The secondary sodium, which has become hot by exchanging heat with the high-temperature primary sodium, rises in the riser pipe 7 and flows into the secondary system loop. Furthermore, a partition wall 11 and a heat shielding plate 12 are provided at the boundary between the hot and cold blenheims to prevent heat from the hot blenheim from being directly transmitted to the cold blenheim.

Further, in this embodiment, a partition wall cylindrical portion 16 concentric with the main body shell 2 of the intermediate heat exchanger is formed at the end of the partition wall 11 facing the main body shell 2 of the intermediate heat exchanger. The upper end of this cylindrical partition part 16 is sized so as to be located near the upper end of the heat exchanger tube, and the lower end of this cylindrical part 16 is located near the lower end of the heat exchanger tube, and the inner surface of the cylindrical partition part 16 facing the main body shell 2 is fitted with at least one ring (two rings 17.17 are shown in the figure). Further, a skirt 18 is attached to the main body shell 2, covering the upper end of the partition wall cylindrical portion 16 and having its lower end located below the heat exchanger tube. Furthermore, skirt 18
A pipe 19 is provided at the upper end of the skirt 18 for feeding inert gas into the space formed by the cylindrical partition 16 and the cylindrical partition 16. The main body barrel 2, the partition wall cylindrical portion 16, and the skirt 18 constitute a manometer seal.

Next, the operation of the above embodiment will be explained.

During the decay heat removal, the primary sodium of the hot brenum flows into the main body shell 2 from the intermediate heat exchanger flow hole 8 and is cooled by heat exchange with the cooling pipe 13. The cooled primary sodium then descends through the heat exchanger tube and flows out from the primary sodium outlet 9 to the cold blemish. In the figure, the flow of primary sodium is shown by solid line arrows for high temperature sodium and by broken line arrows for sodium that has become low temperature. At this time, the temperature of the heat transfer tube bundle 3 becomes lower than that of the hot brenum, but since the argon gas region is below the upper tube plate and extends over the entire hot boule region, the outside of the intermediate heat exchanger in the hot boule region is filled with argon gas. It is a gas atmosphere or a cold blennium region. Therefore, the main body shell 2 of the heat transfer tube bundle 3 portion has a small area in contact with the hot brenum side across the partition wall cylindrical section 16, so that the heat transmitted from the hot brenum side to the cold brenum side through the partition wall cylindrical section 16 is also small. As a result, it is possible to reduce the direct transmission of the heat of the hot brenum to the interior of the intermediate heat exchanger, and therefore it is possible to prevent buckling of the heat transfer tubes due to a radial temperature difference within the main body shell 2. Moreover, since at least one ring 15 is provided on the inner surface of the partition wall cylindrical portion 16 with a slight gap between it and the main body shell 2, a fluid vibration effect is produced.

[Effects of the Invention] As explained above, according to the intermediate heat exchanger of the present invention,
The area formed between the main body of the intermediate heat exchanger and the cylindrical partition wall becomes an argon gas atmosphere or a cold blemish area, which prevents the heat of the hot blemish from being directly transmitted to the inside of the intermediate heat exchanger. . As a result, the temperature difference in the radial direction of the heat exchanger tube bundle can be reduced and buckling of the heat exchanger tubes can be prevented.

Further, since a ring is attached to the inner surface of the partition wall cylinder, there is a slight gap between the partition wall cylinder and the main body cylinder, thereby improving the fluid positioning effect.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view of a conventional intermediate heat exchanger. DESCRIPTION OF SYMBOLS 1... Intermediate heat exchanger, 2... Main body shell 3... Heat exchanger tube bundle, 4... Upper tube sheet 5... Lower tube sheet,
6... Descending pipe 7... Ascending pipe,
DESCRIPTION OF SYMBOLS 10... Pipe bundle support plate 11... Bulkhead, 12... Heat shielding plate 16... Bulkhead cylindrical part, 17... Ring 18... Skirt, 19... Patent attorney rules for piping agents Kensuke (1 person) Figure 1 Figure 2

Claims (3)

[Claims] (1) In an intermediate heat exchanger for a tank-type fast breeder reactor that is suspended and supported within the reactor vessel by a roof slab provided at the upper opening of the reactor vessel, the upper A skirt including a plurality of heat exchanger tubes supported by a tube sheet and a lower tube sheet, the upper end of which is fixed outside the main body shell above the upper tube sheet, and the lower end of which is located below the heat exchange tube bundle. a partition wall having an upper end and a lower end thereof located near the upper end and a lower end of the heat transfer tube, respectively, and surrounding the main body shell and having a partition wall cylindrical portion between the skirt and the main body shell; An intermediate heat exchanger for a tank-type fast breeder reactor, characterized in that an inert gas is sealed in a space formed by the skirt and the skirt. (2) An intermediate heat source for a tank-type fast breeder reactor according to claim 1, wherein at least one ring having a gap with the main body shell is provided on the inner surface of the partition wall cylindrical portion facing the main body shell. exchanger. (3) The intermediate heat exchanger for a tank-type fast breeder reactor according to claim 1, wherein the inert gas is injected from a pipe provided in the skirt.