JPH02128192A - Decentralized nuclear reactor - Google Patents

Abstract

PURPOSE:To contrive the improvement of the reliability and safety of a reactor by making a combination or an integration of a small-sized reactor core part and a steam generator to be modularized. CONSTITUTION:A small-sized reactor core part 23 having a small-scale reactor core 22 and a steam generator 24 thereon are modularized to set a plurality of them in a cooling vessel. Generated heat by the reactor core 22 is heat- exchanged with the water of the steam generator 24 by the natural circulation of a coolant to take out of a reactor containment device so as to utilize to power generation. As desired above, because the generated heat of the reactor core 22 is transmitted to the steam generator 24 to take out of a nuclear reactor containment facility by the coolant naturally circulated, sodium tubing, an intermediate heat exchanger, a pump and the like are not needed. Thereby, since the reliability and profitability of a reactor are heightened and the modification of output can be responded by the increase and decrease of module number, the improvement of safety can be contrived.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a distributed nuclear reactor in which a small reactor core and a steam generator are modularized as a set or integrated.

[Conventional technology]

In conventional nuclear reactors, such as fast breeder reactor plants, the heat generated in the reactor is removed with sodium, which has good thermal conductivity and can easily produce high-temperature steam without being particularly pressurized, and the high-temperature sodium is transferred through piping, pumps, etc. A steam generator installed outside the reactor containment facility exchanged heat with water to generate steam, which drove a turbine.

We will explain the fast breeder reactor "Monju" as a representative example of this system.

Figure 4 shows the main system of the fast breeder reactor "Monju".
In the figure, 1 is the nuclear reactor, 2 is the intermediate heat exchanger, 3 is the primary main circulation pump, 4 is the steam generator, 5 is the secondary main circulation pump, 6 is the air cooler, 7 is the turbine, and 8 is the power generation It is a machine.

In the figure, the cooling system is a primary sodium system consisting of an intermediate heat exchanger 2, a primary main circulation pump 3, piping and left tilting located inside the reactor containment facility, and a steam generator 4 located outside the reactor containment facility. 2 consisting of the main circulation pump 5, piping, left tilt, etc.
It consists of a sub-sodium system, an auxiliary core cooling system including air cooling H6, etc.

The sodium in the reactor 1, which has become high in temperature due to the heat generated by the nuclear fission chain reaction inside the reactor, flows out from the outlet nozzle of the reactor L, transfers heat to the secondary sodium system in the intermediate heat exchanger 2, and is transferred to the primary sodium system. It flows through the main circulation pump 3 and from a nozzle provided at the bottom of the reactor vessel 9.

Secondary sodium type sodium flows from the upper part of the intermediate heat exchanger 2, reverses itself in the lower plenum, rises in the tube, absorbs heat from the primary sodium, and flows out from the upper part. It then passes through the steam generator 4 and returns to the intermediate heat exchanger 2 via the secondary main circulation pump 5.

In this way, the heat generated within the reactor 1 is taken out of the reactor containment facility via the sodium, and the heat generated within the reactor 1 is taken out of the reactor containment facility and
The heat of the sodium is transferred to water to generate steam, which drives a turbine 7 and a generator 8 to generate electricity.

[Problem to be solved by the invention]

As shown in 2, in conventional fast breeder reactors, heat generated in the reactor core is exchanged with water via the primary and secondary sodium systems in a steam generator installed outside the reactor containment facility. Since the steam necessary to drive the turbine was generated by the steam turbine, sodium piping, an intermediate heat exchanger, a pump, etc. were required, which caused problems from the viewpoint of high convertibility and cost reduction.

In addition, when attempting to increase the reactor output, the reactor core becomes larger, and the core's inherent reactivity enters a positive region, resulting in a reduction in safety.

The present invention is intended to solve the above-mentioned problems.The present invention is made by modularizing a small-scale reactor core and a steam generator, which have a small-scale reactor core, and arranging a plurality of them in one cooling vessel. Since the generated heat is transferred to the steam generator and taken out outside the reactor containment facility, sodium piping, intermediate heat exchangers, pumps, etc. are no longer required, improving reliability and economic efficiency, and changing the output can be done by reducing the number of modules. The purpose is to provide a distributed nuclear reactor that can respond by increasing or decreasing the number of units and can improve safety.

[Means to solve the problem]

To this end, the distributed nuclear reactor of the present invention has a small reactor core having a small reactor core and a steam generator provided opposite to the upper part of the small reactor core, which are made into a set or integrated into a module, and the module is assembled into a cooling vessel. It is characterized in that one or more pieces are arranged within.

[Effect]

In the present invention, a small reactor core having a small core and a steam generator installed above the core are modularized, and a plurality of them are installed in a cooling vessel, and the heat generated by the reactor core is transferred into the steam generator by natural circulation of coolant. This system exchanges heat with the water in the reactor and takes it out of the reactor containment facility to be used for power generation.The naturally circulating coolant transfers the heat generated by the core to the steam generator and takes it out of the reactor containment facility. This eliminates the need for sodium piping, intermediate heat exchangers, pumps, etc., improving reliability and economy, and making it possible to change output by increasing or decreasing the number of modules, improving safety. becomes.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory diagram showing an embodiment of a distributed fast reactor according to the present invention, and FIG. 2 is a longitudinal cross-sectional view showing an embodiment of a core-steam generator module according to the present invention. , 21 is a main vessel, 22 is a core/steam generator module, 23 is a small core, 24 is a steam generator, 25 is a seal plug, 26 is a small core, 27 is a core vessel, 28 is a core outer cylinder, 29 is a Flow hole, 30 is a communication pipe, 31 is a support plate, 33 is an inner cylinder, 34 is an outer cylinder, 35 is a protection cylinder, 36 is a heat transfer tube, 37 is a water supply inlet, 3B is a steam outlet, 40 is a fluid flow .

In FIG. 1, the distributed fast reactor has a plurality of core/steam generator modules 22 installed in sodium 20 as a coolant in a main vessel 21 according to the output scale of the reactor. This module 22 includes a small reactor core section 23 and a small reactor core section 2 in which a small-scale fast reactor core is provided on the bottom plate of the main vessel 21.
3 and a steam generator 24 provided in a seal plug 25 at the upper part of the main passenger unit 21 facing the steam generator 24 are modularized with a length of 1 m.

As shown in FIG. 2, a core section 1 containing a small core 26 is shown.
27 is supported by a core outer cylinder 28 fixed to the main vessel 21 via a plurality of support plates 31.

The upper part of the core outer cylinder 28 is narrowed down with an inclined surface, and a plurality of flow holes 29 are provided on the side surface below the small core vessel 27 for circulation of the sodium 20. Further, a pressure-resistant communication pipe 30 for operating control rods and the like is provided between the main customer 2S21 and the core vessel 27.

The steam generator 24 has an inner cylinder 3 fixed to a seal plug 25.
3. It is composed of an outer cylinder 34, a protection cylinder 35 outside the outer cylinder 34, and a heat transfer tube 36 wound in a coil on the outside of the inner cylinder 33.

Further, the inner cylinder 33 is provided with a plurality of flow holes 39 for the VB ring of sodium in the upper part below the liquid level of the sodium 20, and the lower opening faces the opening of the core outer cylinder 28.

Further, the coiled upper end of the heat transfer tube 36 passes between the outer cylinder 34 and the protection cylinder 35 and reaches the water supply population 37 outside the seal plug 35.
The other end of the coil forms a steam outlet 38 between the inner cylinder 33 and the outer cylinder 34 and outside the seal plug 35.

In the core/steam generator module having such a structure, the sodium in the core outer cylinder 28, which has become high in temperature due to the heat generated by the nuclear fission chain reaction in the reactor core 26 of the small reactor core section 23, rises inside the core outer cylinder 28. , inner cylinder 3 of the steam generator 24
3 , rises, and flows out from the flow hole 39 between the inner cylinder 33 and the outer cylinder 34 . The water in the heat transfer tubes 36 supplied from the water supply port 37 exchanges heat with the high temperature sodium flowing out to become steam and is taken out of the reactor containment facility from the steam outlet 38. On the other hand, the sodium cooled by heat exchange becomes a flow 40, descends the slope of the core outer cylinder 28, flows out of the module, and mixes with the sodium 20 in the main passenger unit 21. The sodium 20 in the main vessel 21 is transferred to the core outer cylinder 2.
8 flows into the vicinity of the small core vessel 270 from the flow hole 29 at the bottom of the reactor.

In this way, the natural circulation of sodium can be used to obtain the steam necessary for power generation.

FIG. 3 is a longitudinal sectional view showing another embodiment of the core/steam generator module of the present invention, in which the same numbers as in FIG. 2 indicate the same contents, 41 is a small core, 42 is a core outer cylinder, 43 is a communicating pipe.

This module consists of the outer cylinder of the small reactor core 41 and the steam generator 2.
The reactor core and steam generator are integrated into one structure with the inner cylinder of No. 4, and are fixed to the seal plug 25 on the upper part of the main vessel No. 2. The heat exchange method and steam generation method are
It is similar to the one shown in the figure. In this embodiment, the control rods and the like are operated from the top of the main container 21.

〔Effect of the invention〕

As described above, according to the present invention, a small reactor core and a steam generator are combined into a module, and a plurality of modules are arranged in one cooling vessel, so that the heat generated by the core is transferred to the natural W of the coolant.
1m to exchange heat and take the generated steam out of the reactor containment facility, eliminating the need for sodium piping, intermediate heat exchangers, pumps, etc., improving reliability and economic efficiency, and improving the reliability and efficiency of the reactor core and steam generator. By increasing or decreasing the number of modules, a reactor with arbitrary output can be obtained. In addition, because it is a small reactor core, its inherent safety is high, and furthermore, even if one module fails, heat is removed from the core by other modules, further improving safety and reliability. can.

[Brief explanation of the drawing]

The first is an explanatory diagram showing an embodiment of the distributed fast reactor according to the present invention, FIG. 2 is a cross-sectional view of Ii showing an embodiment of the core/steam generator module according to the present invention, and FIG. 3 is an explanatory diagram showing an embodiment of the distributed fast reactor according to the present invention. FIG. 4 is a vertical sectional view showing another embodiment of the core-steam generator, and is a diagram showing the main system of the fast breeder reactor "Monju". 1... Nuclear reactor, 2... Intermediate heat exchanger, 3... Main circulation pump, 4... Steam generator, 5... Secondary main circulation pump, 20... Sodium, 21 ...Main container, 2
2... Core/steam generator module, 23... Small reactor core section, 24... Steam generator, 25... Seal plug, 26... Small core, 28... Core outer cylinder, 29 ．．
39...Flow hole, 33...Inner cylinder, 34...
Outer cylinder, 35... protection tube, 36... heat transfer tube. Applicant Power Reactor and Nuclear Fuel Development Corporation

Claims (7)

[Claims] (1) A small fast reactor with a small-scale core and a steam generator installed opposite to the upper part of the reactor core are combined into a module, and one or more of the modules are arranged in a cooling vessel. A distributed nuclear reactor featuring: (2) The distributed nuclear reactor according to claim 1, wherein the small reactor core is fixed to the bottom of the cooling vessel, and the steam generator is fixed to the seal plug. (3) The reactor core is housed in an outer cylinder with a flow hole on the side and an opening at the top that is narrowed at the top, and the steam generator has an inner cylinder with a flow hole on the side and an opening at the bottom, and a lower end surrounding the inner cylinder. 3. The distributed nuclear reactor according to claim 1, further comprising an open outer cylinder, and a coiled heat transfer tube wound around the inner cylinder. (4) A claim in which the outer cylinder of the steam generator is surrounded by a protection tube, the heat exchanger tube water supply inlet is provided between the outer cylinder and the protection tube, and the heat exchanger tube steam outlet is provided between the inner cylinder and the outer cylinder. 3. Distributed nuclear reactor according to 3. (5) Claim 1 in which the small reactor core and the steam generator are integrated
Or the distributed nuclear reactor described in 2. (6) The reactor core has a flow hole on the side and the core is housed in an outer cylinder with an opening at the upper end that is narrowed at the top, and the steam generator has a flow hole on the side and an inner cylinder with an opening at the lower end. 6. The steam generator according to claim 5, further comprising an outer cylinder with an opening at the lower end surrounding the inner cylinder, and a coiled heat transfer tube is wound around the inner cylinder, and the outer cylinder of the reactor core and the inner cylinder of the steam generator are integrated. Distributed nuclear reactor. (7) A claim in which the outer cylinder of the steam generator is surrounded by a protection tube, the heat exchanger tube water supply inlet is provided between the outer cylinder and the protection tube, and the heat exchanger tube steam outlet is provided between the inner cylinder and the outer cylinder. 6. The distributed nuclear reactor according to 6.