JPS5999393A - Bwr type 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 the Invention] The present invention relates to a boiling water nuclear reactor, and in particular:! This relates to the connection structure between illφII and the control rod drive rod.

[Technical background of the invention]

Conventionally, boiling water reactors are equipped with a steam separator and a steam dryer above a core that is loaded with a large number of fuel assemblies, and the mixed flow of steam and water generated in this core is separated into steam and water. The steam is separated into water and steam in a steam dryer, and after moisture is removed from the steam in a steam dryer, it is sent to a turbine via a main steam nozzle. ! In addition, a plurality of control rod 1 drive mechanism housings are inserted from below into the reactor pressure vessel by penetrating the bottom wall of the reactor pressure vessel, and the upper end of these control rod drive mechanism housings is inserted into the reactor pressure vessel from below. Each has several control rod guide tubes, and these control rod guide tubes face the lower surface of the reactor core. A control rod drive mechanism is attached to the lower end of the control rod drive mechanism housing, and the control rods (not shown) are guided into the control rod guide tube and moved into the reactor core by the control rod drive mechanism. It is configured so that it can be inserted and pulled out.

By the way, when the control rods are inserted into the reactor core from below, the control rods must be pushed up against gravity in order to insert the reactor scram operation special 5liIJ control rods into the reactor core. There were problems such as the need to improve the reliability of the mechanism's control rod insertion operation. In order to solve this problem, a system in which control rods are inserted into the reactor core from above is being considered. That is, the control rod drive mechanism housings penetrate the lid of the reactor pressure vessel and are inserted into the reactor pressure vessel from above, and these control rod drive mechanism housings are inserted into an annularly formed steam dryer. It is also inserted between the stands A' of the steam/water separator.

Control rod guide tubes are attached to the lower ends of these control rod drive mechanism housings, respectively, and these control rod guide tubes face the upper surface of the reactor core.

A control rod drive mechanism is provided at the upper end of each of the control rod drive mechanism housings.

The control rods are guided by the control rod guide tubes and inserted into and withdrawn from the core from above by a control rod drive mechanism. Therefore, the control rods can be configured to be inserted into the reactor core by gravity during a scram, etc., thereby increasing the reliability of the scram operation and simplifying the configuration of the control rod drive mechanism1. [Problems in the background art] In the above configuration, the vicinity of the upper end of the control rod 1 is configured as shown in FIG. This control unit 1 has a configuration in which blades 2 are arranged in a cross shape, and a fuel assembly 3 is loaded between each blade 2. Reference numeral 4 in the figure is an upper lattice plate.

A connecting portion 5 is formed at the upper end of the control rod 1 and is connected to a drive rod (not shown) that is vertically slidably provided in a control rod drive mechanism housing (not shown). In this case, the connecting portion 5 becomes thicker than the thickness of the blade 2.
For example, in order to stop a nuclear reaction in the reactor core, the fuel assembly 3 is pulled out or inserted while the control rod 1 remains inserted into the reactor core.

At this time, the connecting portion 5 may interfere with the pulling out or insertion movement of the fuel assembly 3, and there is a fear that stable operation cannot be performed.

[Purpose of the invention]

It is an object of the present invention to provide a watercolor nuclear reactor in which the connection structure between the control rods and the drive cylinders enables stable operation without interfering with the extraction or insertion of the fuel assembly. There is a particular thing.

[Summary of the invention]

The boiling water reactor according to the present invention includes a reactor pressure vessel, a plurality of control rod drive mechanisms inserted from one side through the lid of the reactor pressure vessel, and the control rod drive mechanisms. a drive port slidably housed in the housing, a plurality of fuel assemblies disposed below the housing of the control rod drive mechanism, and the plurality of fuel assemblies. A plurality of control rods arranged in a lattice pattern and having a cross-shaped cross section are removably installed in the drive port and the control rod, and a control rod is provided at the upper end of the control rod to control the movement of the fuel assembly when it moves in the vertical direction. This configuration includes a locking portion provided in a shape that does not interfere with each other, and a retaining portion formed at the lower end of the drive rod and connecting the control rod by engaging with the locking portion.

That is, the configuration is such that the locking portion provided at the upper end of the control rod does not interfere with the vertical movement of the fuel assembly.

Therefore, when the fuel assembly moves in the vertical direction, it is not interfered with by the locking portion, and stable operation can be performed, and safety and soundness can be greatly improved.

[Embodiments of the invention]

A simple embodiment of the present invention will be described with reference to FIGS. 2 to V. FIG. 2 is a sectional view showing a schematic configuration of a boiling type nuclear reactor.

Reference numeral 101 in the figure is a nuclear reactor pressure vessel, and a removable lid 102 is attached to the upper part of the vessel. and,
A reactor core 103 is housed in the lower part of the reactor pressure vessel 101 . This core 103 has a large number of fuel assemblies 104
It is constructed by loading it in a grid pattern. The coolant, ie, light water, is configured to flow into these fuel assemblies 104 from below, boil, and flow upward as a two-phase flow of water and steam. Further, a shroud 105 is provided surrounding this core 103. A steam separator 106 is provided above the core 103.

The two-phase flow of water and steam flowing out from the fuel assembly 104 of the reactor core 103 is separated into water and steam by this steam-water separator 106.

Further above the steam/water separator 106, a steam dryer 107 is provided. And the above steam separator 1
The steam separated in step 06 has its moisture removed in this steam dryer 107, and is configured to enter a turbine (not shown) or the like through a main steam nozzle 10B. In addition,
The steam dryer 107 has an annular shape, and a sole member 109 closes the space between the outer circumference of the upper end of the steam dryer 107 and the inner surface of the reactor pressure vessel 10, and the outer circumference of the lower end of the steam dryer 107 and The inner surface of the reactor pressure vessel 101 is closed by a skirt 11O immersed in the reactor water, and is configured to prevent steam from flowing directly to the main steam nozzle 108 without passing through the steam dryer 107. ing. Then, the lid 102 of the reactor pressure vessel 101
A plurality of control rod driving mechanism housing songs 111 are provided passing through the control rod drive mechanism. These control rod drive mechanisms... Unong 11
1 is inserted into the annular steam dryer 107 and further inserted between the stand pipes 106A of the steam/water separator 106. Control rod guide tubes 112 are attached to the lower ends of these control rod drive mechanism housings 111, respectively. These control rod guide tubes 112 have a cruciform cross section and are arranged between the stand pipes 106A of the steam separator 106, with their lower ends facing the upper surface of the reactor core 103. A control rod 113 having a cross-shaped cross section is inserted and guided through these control W guide tubes 112. Furthermore, control rod drive mechanisms 114 are provided at the upper ends of the control rod drive mechanism housings 111, respectively. The control rods 113 are connected to drive ports and doors 115 of these control rod drive mechanisms 114, and guided by the control rod guide tubes 112 to be inserted into the reactor core 103 from above and pulled out upwards. It is composed of

As shown in FIG. 3, the fuel assembly 104 is supported vertically by a core support plate 116 and horizontally by a trench upper lattice plate 117. In FIG. 3, the control rod 113 is inserted about halfway between the fuel assemblies 104 along the control rod guide tube 112. Also, the control rod 113
A roller 118 is provided at the bottom, and a blade protrusion 119 is formed at the top. And this roller 1
18 and the blade protrusion 119, the control rod 113 is smoothly inserted. and control rod 11
A piston 120 is formed at the lower end of 3, and a dashpot 121 formed on the core support plate 116 and the control rod 1
13 is inserted at high speed, the piston 120 is inserted into the Dalasi pot 121. At this time, the piston 12
0 has an opening 120A at the tip, and a drain port 120B in the axial direction.

120C and 120D are formed, water in the dashpot 121 flows through these openings 120A and the drain port 12.
0 B, 120 C, and J 20 D are expelled into the furnace. And as the control @ 113 is inserted, the drain ports 120B, 120c.

The configuration is as follows. The control rod 113 is composed of a blade 122 having a cross-shaped cross section as shown in FIG.

Using boron carbide or no-funium alloy113
And the connection structure of the drive rod 115 will be explained.

That is, a locking portion 123 is formed at the upper end of the control rod 113. This locking part 12.9 is composed of a small grade 124 having a cross-shaped cross section like the blade 122 at the center of the upper end of the blade 122, and this small blade 1j
4. A notch 125 is formed at the lower part. The thickness of the small blade 124 does not exceed the thickness of the blade 122, so that it does not interfere with the movement of the fuel assembly 104 in the vertical direction as in the prior art.

An engaging portion 126 that engages with a locking portion 123 is formed at the lower end of the drive rod 115, as shown in FIG. That is, the locking portion 12 is located at the lower end of the drive port and door 115.
The bottom lid 12 has a cross-shaped slit 127 through which 3 passes.
8 is installed. Therefore, when connecting the control rod 113 and the drive rod 115, the drive rod 115 is lowered and the slit 127 passes through the small grade 124. After the slit 127 passes through the small blade 124, the drive rod 115 is rotated 45 degrees, and the notch 125
and the bottom cover 128 are engaged. Now drive rod 115
The connection between the control rod 113 and the control rod 113 is completed. When separating the control rod 113 and the drive rod 115, the above-described connecting operation may be performed in the reverse order.

According to the above configuration, the thickness of the small blade 124 provided at the upper end of the control 5113 does not exceed the thickness of the blade 122, and therefore, when the control rod 113 is inserted as in the conventional case, if V/% -F'i, then the atom When carrying out combustion exchange with the furnace stopped, stable vertical movement can be performed without interfering with the vertical mt of the fuel assembly 104.

Note that the braking mechanism used when inserting the control rod 113 at high speed may be configured using a spring, or the braking mechanism may be fixed to the control rod drive mechanism so that the control rod drive mechanism and the control rod 113
An example of braking by the control rod drive mechanism will be explained by inserting the control rod into a connected reactor core. That is, the locking portion 123 is formed on the extension of one side of the blade 122.
A notch 130 is formed in the lower part of the small plate 129 of the penis. Above small grade 1
The thickness of blade 29 does not exceed the thickness of blade 122. Therefore, as in the previous embodiment, the configuration does not interfere with the vertical movement of the fuel assembly 104. on the other hand,
At the lower end of the drive rod 115, there is a retaining part 126 that engages with the above-mentioned locking part 123θ and has an rzX shape as shown in FIG.
-a has been written down. That is, a bottom cover 133 having a slit 132 through which the small blade 129 passes is attached to the lower end of the drive rod 115. Therefore, the control rod 11
3 and the drive rod 115, the drive rod 11
5 is lowered and the small blade 129 is passed through the slit 132. After passing through the drive rod 115, the drive rod 115 is rotated 90 degrees to engage the notch 13θ and the bottom cover 133.

The connection between the drive rod 115 and the control rod 113 is now completed. When separating the drive rod 115 and the control rod 113, the above-described connecting operation is performed in the reverse order. Incidentally, the same parts as in the above embodiment are denoted by the same reference numerals, and the explanation thereof is omitted.

〔Effect of the invention〕

A boiling water reactor according to the present invention includes a reactor pressure vessel, a plurality of control rod drive mechanism housings inserted from above through a lid of the reactor pressure vessel, and a plurality of control rod drive mechanism housings inserted into the control rod drive mechanism housing. A drive port, which is housed so as to be slidable in the vertical direction, a plurality of fuel assemblies disposed below the control rod drive mechanism housing, and a cross section arranged in a grid pattern between the plurality of fuel assemblies. A plurality of control rods having a cross shape and being detachably attached to the drive rod, and a lock provided at the upper end of the control rod in a shape that does not interfere with the vertical movement of the fuel assembly. and a retaining part that is formed at the lower end of the drive rod and connects the control rod by engaging with the locking part.

That is, the structure is such that the locking part provided at the upper end of the control rod does not interfere with the vertical movement of the fuel assembly.

Therefore, when the fuel assembly moves in the vertical direction, it can operate stably without being interfered with by the locking parts, greatly improving safety and soundness. .

[Brief explanation of the drawing]

Figure 1 is a perspective view of the vicinity of the upper end of the control rod showing a conventional example;
7 to 7 are diagrams showing one embodiment of the present invention. FIG. 2 is a cross-sectional view showing the schematic configuration of a boiling water reactor, FIG. 3 is a cross-sectional view showing a state in which the control rods are half inserted, and FIG. 4 is a sectional view of the vicinity of the lower end of the control rod, FIG. 5 is a perspective view of the control rod, FIG. 6 is a perspective view of the vicinity of the upper end of the control rod, and FIG. 7 is a perspective view of the lower end of the drive rod. 8 and 9 are views showing another embodiment, in which FIG. 8 is a perspective view of the vicinity of the upper end of the control rod, and FIG. 9 is a perspective view of the drive port and the lower end of the control rod. 101... Reactor pressure vessel, 102... Lid of reactor pressure vessel, 104... Fuel assembly, 111... Control rod drive mechanism...Usong, 113... Control rod, 11
5... Drive port, C, 123... Locking part, 126...
Engagement part. Applicant's agent Patent attorney Takehiko Suzue Figure 1 459 Figure 2 Figure 3 Figure 5 Figure 6 Figure 23

Claims (1)

[Claims] (++ IQ child reactor pressure vessel and the lid f of this reactor pressure vessel: A plurality of control rod drive mechanism housings penetrated and inserted from above, and the control rod drive mechanism can be slid vertically into the housing. a plurality of fuel assemblies disposed below the control rod drive mechanism housing; and a plurality of fuel assemblies arranged in a lattice shape between the plurality of fuel assemblies and having a cross-shaped cross section, and the drive rod and a plurality of control rods that are detachably provided; a locking portion provided at the upper end of the control rod in a shape that does not interfere with the vertical movement of the fuel assembly; and a locking portion provided at the lower end of the drive rod. formed and engaged with the above-mentioned locking part.