JPH10160883A - Cooling mechanism of rector vessel wall - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling mechanism of a reactor vessel wall capable of mitigating the thermal stress generating in the reactor vessel wall. SOLUTION: In the cooling mechanism of reactor vessel wall in which a reactor vessel 5 placing a core 1 inside is separated in an upper plenum 2 and an intermediate plenum 3, an inner liner plate 7 and an outer liner plate 6 are placed in the inner and outer positions of the reactor vessel 5 along the reactor vessel 5 wall, an upflow path 9 for making the low temperature primary coolant from the intermediate plenum 2 contact the reactor vessel 5 wall and rise is formed in between the outer liner plate 6 and the reactor vessel 5 wall, and a downflow path 10 for making the primary coolant from the upflow path 9 flow down and flow out to the upper plenum from inside liner flow holes 8 provided in the inner liner plate 7 is formed in between the outer liner plate 6 and the inner liner plate 7, flowrate passing the inner liner flow holes 8 provided in the inner liner plate 7 is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a nuclear reactor, for example,
The present invention relates to a cooling mechanism for a reactor vessel wall of a fast reactor using liquid metal as a secondary coolant.

[0002]

2. Description of the Related Art A conventional reactor vessel wall cooling mechanism is shown in FIG.
This will be described with reference to FIG. FIG. 2 is a vertical side view schematically showing a fast reactor, and FIG. 3 is a vertical side view showing a cooling mechanism of a reactor vessel wall. In FIG. 2, 1 is a core, 2 is an upper plenum,
5 is a reactor vessel, 13 is a lower plenum, 14 is a roof deck, 15 is an inlet pipe, 16 is an outlet pipe, 17 is a core upper mechanism, 18 is a core support structure, and 1 is the inside of the reactor vessel 5.
It is filled with liquid metal sodium (hereinafter referred to as a primary coolant) 19 as a secondary coolant, and is operated at an inlet pipe 15 during operation.
From the core 1 to the upper plenum 2 as high-temperature primary coolant, and from the upper plenum 2 via an outlet pipe 16 to an external heat exchanger (not shown). ), Cool it down here,
A low-temperature primary coolant is introduced again from a pump (not shown) to the inlet pipe 15.

[0003] Inside the reactor vessel 5 wall, a cooling mechanism for the reactor vessel wall is provided to protect the reactor vessel 5 wall from the high temperature primary coolant of the upper plenum 2. The cooling mechanism of the reactor vessel wall will be described with reference to FIG. 3. 1 is a reactor core, 2 is an upper plenum, 3 is an intermediate plenum, 4 is a partition plate, 5 is a reactor vessel, 6 is an outer liner plate, and 7 is an inner liner. Plate, 8 is an inner liner flow hole provided in the inner liner plate 7, 9 is an ascending flow path formed between the outer liner plate 6 and the wall of the reactor vessel 5, 10 is the outer liner plate 6 and the inner liner plate 7 1 is a free liquid level of the upper plenum 2, 12 is a free liquid level above the ascending flow path 9 and the descending flow path 10, and from the core support structure 18 in FIG. The low-temperature primary coolant that has flowed into the reactor vessel 5 is guided to the ascending flow path 9 and is raised while being in contact with the walls of the reactor vessel 5 to cool the reactor vessel 5. 6 and mixed with the primary coolant flowing into the descending flow path 10 10 lowers the leads from the inner liner flow hole 8 to the upper plenum 2. At this time, the free liquid level 1 of the cooling mechanism is located above the ascending flow path 9 and the descending flow path 10.
2 are formed.

[0004]

The cooling mechanism of the reactor vessel wall shown in FIG. 3 suppresses the temperature rise of the wall of the reactor vessel 5 and moderates the flow of the free liquid level 12 of the cooling mechanism. Since the height of the free liquid surface 11 of the upper plenum 2 and the height of the free liquid surface 12 formed above the ascending flow passage 9 and the descending flow passage 10 are the same, high-temperature primary cooling of the upper plenum 2 is intended. The area 20 immediately below the free liquid level 12
, A portion of the wall of the reactor vessel 5 rises to near the temperature of the high-temperature primary coolant 19 in the upper plenum 2. In this case, the thermal stress generated on the free liquid surface 12 of the reactor vessel 5 wall, that is, the thermal stress due to the temperature gradient in the height direction is almost the same as when the cooling mechanism is not provided, and the cooling mechanism is installed. Would defeat the purpose of doing so.

The present invention has been made in view of the above problems, and has as its object to maintain the reactor vessel wall at a low temperature and reduce the thermal stress generated on the reactor vessel wall. It is an object of the present invention to provide a reactor vessel cooling mechanism that can be mitigated.

[0006]

In order to achieve the above object, the present invention separates the interior of a reactor vessel, in which a reactor core is installed, into an upper plenum and an intermediate plenum, and separates an inner liner plate and an outer liner plate. Elevation installed inside and outside the reactor vessel along the reactor vessel wall to raise the low temperature primary coolant from the intermediate plenum between the outer liner plate and the reactor vessel wall while making contact with the reactor vessel wall A down flow path is formed, which forms a flow path and lowers the primary coolant from the ascending flow path between the outer liner plate and the inner liner plate to flow out from the inner liner flow hole provided in the inner liner plate to the upper plenum. In the cooling mechanism of the formed reactor vessel wall, the flow rate of the inner liner flow hole provided in the inner liner plate is adjusted to adjust the height of the free liquid surface formed above the ascending flow path and the descending flow path. Upper plenum freedom It is higher than the height of the surface (claim 1).

Further, according to the present invention, the inside of a reactor vessel in which a reactor core is installed is divided into an upper plenum and an intermediate plenum, and an inner liner plate and an outer liner plate are located at positions inside and outside the reactor vessel along a wall of the reactor vessel. A rising flow path between the outer liner plate and the reactor vessel wall for raising the low-temperature primary coolant from the intermediate plenum while contacting the reactor vessel wall, and forming the outer liner plate and the inner liner plate with each other. A cooling system for a reactor vessel wall having a descending passage for lowering a primary coolant from an ascending passage and flowing out from an inner liner flow hole provided in an inner liner plate to an upper plenum. The height of the upper end of the plate is equal to or higher than the height of the free liquid surface of the upper plenum, and the height of the free liquid surface formed above the ascending flow passage and the descending flow passage is adjusted to the height of the upper plenum. From the free liquid level It is high (claim 2).

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a cooling mechanism for a reactor vessel wall according to the present invention will be described with reference to an embodiment shown in FIG. 1; 1 is a core, 2 is an upper plenum, 3 is an intermediate plenum, 4 is a partition plate, 5 is a reactor vessel, 6 is an outer liner plate, 7 is an inner liner plate, 8 is an inner liner flow hole provided in the inner liner plate 7, and 9 is formed between the outer liner plate 6 and the reactor vessel 5 wall. Ascending flow path, 10 is a descending flow path formed between the outer liner plate 6 and the inner liner plate 7, 11 is a free liquid level of the upper plenum 2, and 12 is a free level above the ascending flow path 9 and the descending flow path 10. At the liquid level, the flow rate of the flow through the inner liner flow hole 8 provided in the inner liner plate 7 is adjusted, that is, the flow path cross-sectional area of the inner liner flow hole 8 is changed, and The height of the free liquid surface 12 formed above is adjusted to the free liquid surface of the upper plenum 2. It is higher than the first height.

The height of the upper end of the outer liner plate 6 may be equal to or higher than the height of the free liquid surface 11 of the upper plenum 2. In the cooling mechanism for the reactor vessel wall shown in FIG. 1 described above, by adjusting the flow rate through the inner liner flow hole 8 provided in the inner liner plate 7, the cooling mechanism is formed above the ascending flow path 9 and the descending flow path 10. The height of the free liquid surface 12 is higher than the height of the free liquid surface 11 of the upper plenum 2, and the heat of the high-temperature primary coolant in the upper plenum 2 is not directly transmitted to the region 20 directly below the free liquid surface 12. Therefore, the wall of the reactor vessel 5 is kept at a low temperature, and the thermal stress generated on the wall of the reactor vessel 5 is reduced.

The height of the upper end of the outer liner plate 6 is set to be equal to or higher than the height of the free liquid surface 11 of the upper plenum 2, and a free space formed above the upflow channel 9 and the downflow channel 10 is formed. The height of the liquid level 12 may be higher than the height of the free liquid level 11 of the upper plenum 2. Also in this case, the heat of the high-temperature primary coolant in the upper plenum 2 is transferred to the region 20 directly below the free liquid level 12.
, The wall of the reactor vessel 5 is kept at a low temperature, and the thermal stress generated on the wall of the reactor vessel 5 is reduced.

[0011]

As described above, the cooling mechanism for the reactor vessel wall according to the present invention (1) adjusts the flow rate through the inner liner flow hole provided in the inner liner plate to increase the flow rate above the ascending flow path and the descending flow path. The height of the free liquid surface formed in the upper plenum is higher than the height of the free liquid surface of the upper plenum, or (2) the height of the upper end of the outer liner plate is the same as the height of the free liquid surface of the upper plenum. Or more, the height of the free liquid surface formed above the ascending flow passage and the descending flow passage is made higher than the height of the free liquid surface of the upper plenum, and the temperature of the high-temperature primary coolant in the upper plenum is increased. Heat is not transmitted directly to the area just below the free liquid level above the ascending flow path and the descending flow path, so that the reactor vessel wall can be kept at a low temperature and the thermal stress generated on the reactor vessel wall can be reduced. be able to.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view showing an embodiment of a cooling mechanism for a reactor vessel wall of the present invention.

FIG. 2 is a vertical sectional side view schematically showing a conventional fast reactor.

FIG. 3 is a vertical sectional side view showing a cooling mechanism of a reactor vessel wall provided in the fast reactor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Core 2 Upper plenum 3 Intermediate plenum 4 Partition plate 5 Reactor vessel 6 Outer liner plate 7 Inner liner plate 8 Inner liner flow hole 9 Up flow path 10 Down flow path 11 Free liquid level of upper plenum 2 12 Up flow path 9 and Free liquid level above the descending flow path 10 19 Primary coolant 20 Area just below the free liquid level 12

Claims (2)

[Claims] 1. A reactor vessel in which a reactor core is installed is divided into an upper plenum and an intermediate plenum, and an inner liner plate and an outer liner plate are provided at positions inside and outside the reactor vessel along the reactor vessel wall, An ascending flow path is formed between the outer liner plate and the reactor vessel wall to raise the low-temperature primary coolant from the intermediate plenum while contacting the reactor vessel wall, and between the outer liner plate and the inner liner plate. In a cooling mechanism for a reactor vessel wall having a descending flow passage for lowering primary coolant from an ascending flow passage and flowing out from an inner liner flow hole provided in the inner liner plate to an upper plenum, the cooling system is provided on the inner liner plate. The height of the free liquid surface formed above the ascending flow passage and the descending flow passage is adjusted to be higher than the height of the free liquid surface of the upper plenum by adjusting the passing flow rate of the inner liner flow hole. Reactor vessel wall Cooling mechanism. 2. The reactor vessel in which a reactor core is installed is separated into an upper plenum and an intermediate plenum, and an inner liner plate and an outer liner plate are provided at positions inside and outside the reactor vessel along the reactor vessel wall, An ascending flow path is formed between the outer liner plate and the reactor vessel wall to raise the low-temperature primary coolant from the intermediate plenum while contacting the reactor vessel wall, and between the outer liner plate and the inner liner plate. In a cooling mechanism for a reactor vessel wall having a descending passage for lowering primary coolant from an ascending passage and flowing out from an inner liner flow hole provided in an inner liner plate to an upper plenum, an upper end of the outer liner plate The height of the free plenum is equal to or higher than the height of the free liquid level of the upper plenum, and the height of the free liquid level formed above the ascending and descending flow paths is adjusted to the level of the free liquid level of the upper plenum. Specially, it is higher than the height. Reactor vessel wall cooling mechanism.