JPH06281102A - Pressurized water reactor steam generator - Google Patents

Abstract

(57) [Summary] [Purpose] It is possible to prevent accidents where the primary coolant containing radioactivity leaks into the secondary coolant containing no radioactivity.
(EN) A steam generator for a pressurized water reactor capable of efficiently transferring heat of a primary coolant to a secondary coolant. [Structure] A primary cooling chamber provided below the partition wall for circulating the primary cooling medium, a secondary cooling chamber provided above the partition wall for vaporizing the secondary coolant, and a penetrating the partition wall. And a heat exchanger arranged in a line, the heat exchanger enclosing a heat medium for natural circulation and convection in a pipe that loops between the primary cooling chamber and the secondary cooling chamber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam generator for a pressurized water reactor, and more particularly to a steam generator for preventing accidental leakage of a primary coolant into a secondary coolant.

[0002]

2. Description of the Related Art Heat naturally flows from a high temperature portion to a low temperature portion under a finite temperature difference, as is derived from the second law of thermodynamics. Therefore, such a flow of heat (heat transfer) is an irreversible process and thermodynamically causes an increase in the amount of entropy.

Generally, when considering the transfer or transfer of thermal energy, a process by so-called "heat transport" in which some kind of fluid medium (gas, liquid, etc.) serves as a carrier and is transported by receiving another power, and thermal energy are generally considered. It is roughly divided into the so-called "heat transfer phenomenon" process in which it naturally transfers and moves into another medium under a finite temperature difference.

In a pressurized water reactor, the heat generated by nuclear fission in the core is transferred to the steam generator by the primary coolant, and the heat transfer phenomenon in the steam generator heats the secondary coolant to generate steam. To occur.

FIG. 2 is an explanatory view schematically showing the structure of a steam generator used in a conventional pressurized water reactor. As shown in the figure, the primary coolant 3a heated by the heat generated in the pressurized water nuclear reactor core 1 is circulated through the steam generator 2 and the core 1 via the primary pipe 3 by the primary coolant pump 4.

The heated primary coolant 3a is the steam generator 2
When it passes through the heat transfer tube group 2a composed of a large number of U-shaped thin tubes in the upper part of the above, it gives heat to the secondary coolant 5a introduced from above and is discharged from the lower part.

The secondary coolant 5a takes away heat to become steam 5b, which is introduced into the turbine 6 through the secondary system pipe 5 to generate electric power, condensed by the condenser 7 and condensed by the feed water pump 8 again by the steam generator. Guided to 2.

[0008]

In such a pressurized water reactor, in a heat transfer tube composed of a large number of thin tubes of a steam generator, a primary coolant passing through the narrow tubes is fissioned into a secondary coolant flowing outside the narrow tubes. Since the heat generated by the reaction is transferred, it has a structural weak point in the pressurized water reactor. That is,
The damage to the tubules may cause the primary coolant containing radioactivity to leak into the secondary coolant containing no radioactivity, with the worst possible release of radioactivity into the atmosphere.

The present invention can prevent an accident in which the primary coolant containing radioactivity leaks into the secondary coolant containing no radioactivity, and the heat of the primary coolant is efficiently transferred to the secondary coolant. The purpose is to obtain a pressurized water reactor steam generator capable of transmitting.

[0010]

In the steam generator for a pressurized water nuclear reactor according to the invention described in claim 1, the secondary coolant is steamed by the heat of the high-temperature primary coolant circulating in the pressurized water nuclear reactor. In the steam generator to be vaporized, a primary cooling chamber in which a primary coolant provided below the partition wall is circulated, a secondary coolant chamber in which a secondary coolant provided above the partition wall is vaporized, and And a heat exchanger arranged through the partition wall,
The heat exchanger encloses a heat medium that causes natural circulation and convection in a pipe that loops between the primary cooling chamber and the secondary cooling chamber.

According to a second aspect of the present invention, there is provided a pressurized water nuclear reactor steam generator according to the first aspect, wherein the primary cooling chamber and the secondary cooling chamber are provided. A steam generator for a pressurized water reactor, wherein the pipe diameter of one of the rising pipes of the loop-like pipe is expanded below the partition wall and the diameter of the other rising pipe is expanded above the partition wall.

[0012]

In the present invention, a primary cooling chamber provided below the partition wall in which the primary coolant is circulated, and a secondary cooling material chamber provided above the partition wall to vaporize the secondary coolant, And a heat exchanger arranged so as to penetrate through the partition wall, wherein the heat exchanger encloses a heat medium for natural circulation convection in a pipe that loops between the primary cooling chamber and the secondary cooling chamber. Since the primary coolant containing radioactivity and the secondary coolant containing no radioactivity do not directly meet the heat transfer wall to perform heat transfer, the radioactivity into the secondary coolant It is possible to prevent a leakage accident.

Further, since the heat medium deprives the heat of the primary coolant and is transported to the side of the secondary coolant by natural convection, no special means for moving the heat medium is required. Energy is used only to generate convection. Therefore, the heat of the primary coolant can be efficiently transferred to the secondary coolant.

Further, in the steam generator of the present invention, preferably, the diameter of one of the pipes that goes around the primary cooling chamber and the secondary cooling chamber in a loop shape is enlarged below the partition wall of the rising pipe and the other rising pipe is expanded. Since the diameter of the upper side of the partition wall is expanded, the heat medium in the loop-shaped pipe that goes from the primary cooling chamber to the secondary cooling water can favorably perform natural circulation convection.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view schematically showing the construction of one embodiment of the steam generator of the present invention. As shown in the figure, the steam generator 11 has a thick primary coolant chamber 13 in which a high temperature primary coolant 12 is circulated and a secondary coolant chamber 16 in which a secondary coolant 14 and steam 15 are circulated. It is separated by a partition wall 17.

At least one set of perforation holes 1 is formed in the partition wall 17.
8 is formed, and at least one heat exchanger 20 configured by a pipe 19 penetrating the perforation hole 18 and looping around the primary cooling chamber 13 and the secondary cooling chamber 16 is provided. A heat medium 21 is sealed inside the loop-shaped pipe 19.

Further, the diameter of one of the rising pipes 22 penetrating the at least one set of holes 18 is expanded below the partition wall 17. Further, in the other rising pipe 23, the diameter of the pipe above the partition wall 17 is expanded.

Therefore, the heat medium flow rising by receiving heat from the primary coolant 12 moves to the secondary cooling chamber 16 through the pipe 22 below the partition wall 17 whose diameter is expanded. Becomes Furthermore, the transferred heat medium 21 vaporizes the secondary cooling material 14, and the heat medium 21 that has released heat is
The other pipe 2 whose diameter above the partition wall 17 is expanded
3 and down to the primary cooling chamber 16 to form natural circulation convection.

As described above, the heat medium 21 forms natural circulation convection in the pipes 19 arranged in a loop, takes the heat of the primary coolant, transports it to the secondary coolant, and supplies it. Since no special means for moving the heat medium is required, the heat of the primary coolant can be efficiently transferred to the secondary coolant.

Although only one heat exchanger 20 is shown in FIG. 1 which is schematically shown, a large number of such heat exchangers 20 are actually provided.

The present steam generator can reduce the trouble that the primary coolant leaks to the secondary side for the following reason. (1) Since the partition wall that separates the primary coolant and the secondary coolant can be made sufficiently thick, it is unlikely that a radiation accident will occur due to damage to the partition wall. (2) Even if the primary coolant side of the heat exchanger is damaged and the primary coolant flows into the heat exchanger, in order to leak into the secondary coolant, in addition to the secondary coolant side, the heat exchanger Damage must occur. That is, the primary coolant will not leak into the secondary coolant unless subsequent double damage occurs.

[0022]

As described above, the present invention provides a primary cooling chamber provided below the partition wall, in which the primary cooling material is circulated,
It has a secondary coolant chamber for vaporizing a secondary coolant provided above the partition wall, and a heat exchanger arranged so as to penetrate through the partition wall, and the heat exchanger is the primary cooling chamber. Since the heat medium that circulates naturally and convection is enclosed in the pipe that loops around the secondary cooling chamber, the primary coolant containing radioactivity and the secondary coolant containing no radioactivity are directly heated. Since heat is not transferred through the transfer wall, it is possible to prevent accidental leakage of radioactivity into the secondary coolant.

Further, since the heat medium deprives the heat of the primary coolant and is transported to the side of the secondary coolant by natural convection, no special means for moving the heat medium is required. Energy is used only to generate convection. Therefore, the heat of the primary coolant can be efficiently transferred to the secondary coolant.

Further, in the steam generator of the present invention, preferably, the diameter of one rising pipe of the pipe that goes around the primary cooling chamber and the secondary cooling chamber in a loop shape is expanded below the partition wall of the rising pipe and the other rising pipe is expanded. Since the diameter on the upper side of the partition wall is expanded, the heat medium in the loop-shaped pipe that goes from the primary cooling chamber to the secondary cooling water has an effect of favorably performing natural circulation convection.

[Brief description of drawings]

FIG. 1 is an explanatory view schematically showing a configuration of an embodiment of a steam generator of the present invention.

FIG. 2 is an explanatory diagram schematically showing a configuration of a steam generator used in a conventional pressurized water nuclear reactor.

[Explanation of symbols]

 11 ... Steam generator, 12 ... Primary coolant, 13 ... Primary coolant chamber, 14 ... Secondary coolant, 15 ... Steam, 16 ... Secondary coolant chamber, 17 ... Partition wall, 18 ... Perforation hole, 19 ... Piping, 20 ... Heat exchanger, 21 ... Heat medium, 22 ... Rise pipe, 23 ... Rise pipe,

Claims (2)

[Claims] 1. A steam generator for evaporating a secondary coolant by heat of a high-temperature primary coolant circulating in a pressurized water reactor, wherein a primary cooling chamber provided below a partition wall, in which the primary coolant is circulated. And a secondary coolant chamber that vaporizes a secondary coolant provided above the partition wall, and a heat exchanger that is arranged to penetrate the partition wall, and the heat exchanger is the primary A steam generator for a pressurized water nuclear reactor, characterized in that a heat medium for natural circulation and convection is enclosed in a pipe that loops between the cooling chamber and the secondary cooling chamber. 2. The steam generator for a pressurized water reactor according to claim 1, wherein a diameter of one of the rising pipes of the pipe that goes around the primary cooling chamber and the secondary cooling chamber in a loop shape is lower than a partition wall. Extended,
A steam generator for a pressurized water reactor, wherein the diameter of the other rising pipe above the partition is expanded.