JPH01116497A - Boiling water type nuclear 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] [Industrial application field] The present invention relates to the structure of nuclear reactors, and in particular to safety.

Concerning boiling water reactors with improved economic efficiency.

(Conventional technology) Conventional boiling water reactors have a shroud head, steam separator, steam dryer, etc. installed in the upper part of the reactor core, as described in Corona Publishing [Atomic Coplant Engineering] p. 75.
The control rods had to be inserted from below, which made the control rod drive mechanism complicated, and the reliability of the drive in the event of an accident was compromised.

-Also, the length of the pressure vessel was longer than that of the wooden processing furnace, which increased construction costs. Furthermore, during fuel exchange, the lid of the pressure vessel was removed, and the steam separator and steam dryer at the top of the core were removed before fuel exchange.

(Problems to be solved by the invention) In the above-mentioned conventional technology, since the control rod is inserted against gravity,
The control rod drive mechanism is becoming more complex, and it also concerns whether the control rods will be driven in the event of an accident.

It was less reliable than letting it fall naturally from above using gravity.

Furthermore, pressure vessels have a long body because they have a steam separator, steam dryer, etc., and when replacing fuel, the steam separator and steam dryer must be removed before the fuel is replaced. This was a factor that raised operating costs.

An object of the present invention is to improve safety by inserting control rods from the top, shorten the length of the pressure vessel, and improve economic efficiency by reducing the number of man-hours required for fuel exchange.

[Means for solving problems]

The above purpose is to reduce the size of steam separators and steam dryers,
By installing it outside the pressure vessel.

achieved.

[Effect]

The steam separator and steam dryer have been miniaturized and installed outside the pressure vessel, so there are no obstacles in the upper part of the reactor core, and control rods can be inserted from the top.

Furthermore, when replacing fuel, it is possible to replace the fuel simply by opening the lid of the pressure vessel, reducing the number of man-hours. Furthermore, the space above the core can be narrowed, and the length of the pressure vessel can be shortened.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. 1st
The figure is a system diagram of the apparatus of the present invention, and FIGS. 2 to 4 are system diagrams of other embodiments.

First, the configuration of each device will be explained using FIG.

In the figure, the interior of the reactor pressure vessel 1 basically consists of a reactor core 2. It is composed of a control rod guide tube 3 into which a control rod 4 is inserted, and a jet pump 15. The control rods 4 are driven by a control rod drive device 5. A main steam pipe 6 extends from the upper part of the reactor pressure vessel 1 and reaches a power generation turbine 12 via a steam/water separation pressure vessel 7. Inside the steam/water separation pressure vessel 7, there are a steam separator 8 and a steam dryer 9. Shura ° Wood Head 1
A drain pipe 12 connects the lower part of the steam/water separation pressure vessel and the return pipe 14. Power generation turbine 1
A condenser 13 is installed at the bottom of the reactor pressure vessel 1 , and a return pipe 14 is connected to the reactor pressure vessel 1 .

Next, the function of each device will be explained.

Reactor water turns into steam in the reactor core 2, directly enters the main steam pipe 6, and then enters the steam-water separation pressure vessel 7. Inside the steam/water separation pressure vessel 7, there is a small, high-performance steam/water separator 8 and a steam dryer 9 on the shroud head 10, and as the steam passes through these, moisture is removed and the steam becomes dry steam. becomes.

The moisture removed in the steam/water separation pressure vessel 7 travels through the upper part of the shroud head 10, passes through the drain pipe 11, enters the return pipe 14, and returns to the reactor core. Steam water separator8.
The steam that has passed through the steam dryer 9 is led to the turbine 12, then turns into water in the condenser 11, passes through the return pipe 14, and returns to the core by the jet pump 15.

In the system of the present invention, the steam separator 8 and the steam dryer 9 are installed outside the reactor pressure vessel 1, so 1) there is no need for the shroud head 10 to cover the entire reactor core. 2) Since it is separated from the reactor core, it can easily take any shape. From these points of view, it is possible to design the shape to be optimal for moisture removal, and it is possible to downsize and improve performance. 8. Steam/water separator with the conventional shape. When the steam dryer 9 is taken out of the reactor pressure vessel 1,
The steam/water separation pressure vessel 7 becomes large. Steam water separator8. If the steam dryer 9 can be made smaller and the steam/water separation pressure vessel 7 can be made smaller, the equipment will also be simpler.

The system shown in Figure 1 can be expected to have the following effects. First, the steam/water separator 8. With the miniaturization of the steam dryer 9, the length of the equipment including the 1M slave reactor pressure vessel 1 and the steam/water separation pressure vessel 7 can be shortened, and the height of the reactor containment vessel can be reduced. Second, the steam/water separator 8. Even if a failure occurs in the steam dryer 9, it will not affect the reactor core 2 because it is separated from the reactor core 2. Thirdly, since there is no structure above the reactor core 2, the control rod system can be installed at the top, which simplifies the control rod drive device 5.

Reliability is further improved by allowing the control rod 4 to fall under its own weight in the event of an accident. Fourthly, fuel rods can be replaced simply by opening the upper cover of the reactor pressure vessel 1, eliminating the conventional process of removing a steam separator and a steam dryer, and shortening the fuel replacement time.

FIG. 2 shows another embodiment of the steam/water separator pressure vessel 7. If the steam separator 8 and the steam dryer 9 are shaped so that they can be installed in the main steam pipe 6, drain can be recovered simply by providing the outer pipe 16 for steam and water separation and creating a double pipe structure.

FIG. 3 shows another embodiment of the outer tube 16 for steam/water separation shown in FIG. 2. If the steam separator 8 and the steam dryer 9 are of the horizontal type, the main steam pipe 6 can be extended right sideways from the pressure vessel, similar to the main steam pipe 6 of a conventional boiling water reactor, and as a result, The height of the reactor containment vessel can be lowered without making the main steam pipe 6 longer, and because the main steam pipe 6 is in a horizontal direction compared to FIG. 2.

FIG. 4 shows an embodiment similar to FIG. 3, but the control rod system is attached to the bottom of the reactor pressure vessel 1, similar to current boiling water reactors. Considering only the removal of the pressure vessel lid during fuel exchange, the structure shown in FIG. 4 can simplify the work.

〔Effect of the invention〕

According to the present invention, there is no need for a shroud head large enough to cover the entire reactor core, the equipment can be made more compact, the height of the reactor containment vessel can be lowered, the control rod system can be installed at the top of the core, and in the event of an accident Safety is improved because the control rod falls under its own weight.

Additionally, since fuel can be replaced simply by opening the reactor pressure vessel lid, the number of man-hours required for fuel replacement is reduced.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of an embodiment of the present invention, and FIG. 2 is a system diagram of an embodiment of the present invention. FIGS. 3 and 4 are system diagrams of other embodiments of the present invention.

Claims (1)

[Scope of Claims] 1. A reactor pressure vessel, a reactor core, a control rod for controlling a reaction in the reactor core, and a control rod guide tube for guiding the control rod to the reactor core; In a nuclear reactor comprising a control rod drive device that drives the control rods, a moisture removal device for steam generated in the reactor core, and a main steam pipe that guides the steam to a turbine, the moisture removal device is connected to the main steam A boiling water nuclear reactor characterized by being installed in a vertical or horizontal pressure vessel for water removal installed in the middle of a pipe.