JPS5999295A - Shield plug device - 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 shielding plug device installed at the upper end opening of a nuclear reactor vessel to shield radiation and heat.

[Technical outpost of the invention and its problems] The fixed plug fixed to the upper opening of the reactor vessel of a fast speed booster reactor has a radiation shielding function and a heavy object support for supporting heavy objects such as rotating plugs and onboard equipment. functions and heat shielding functions are required.

Therefore, it is possible to divide the fixed plug into a -Y section fixed plug and a lower fixed plug, with the upper fixed plug mainly having a radiation shielding function and a heavy object support function, and the lower fixed plug mainly having a heat shielding function. There is. on the other hand,
As nuclear reactors become larger, the weight of rotating plugs, onboard equipment, etc. increases, so the demands on the upper fixed plug as a support function tend to become more severe.

However, increasing the thickness of the upper fixing plug in order to increase its strength is not preferable because it increases the weight of the fixing plug itself and increases thermal stress. So P, J1
In order to avoid increasing the thickness of the part fixing plug and to fully meet the demands of high-end construction, a hollow top fixing plug with a large number of reinforcing ribs inserted between two upper and lower plates has been proposed. Furthermore, by configuring the upper fixing plug to circulate cooling gas along the lower surface of the plug to reduce thermal stress, it is possible to improve the eave height and increase the rigidity, thereby improving the film support function.

These 111i structures have a large number of thermocouples installed in each part, with the main purpose of monitoring the temperature conditions in each operation mode, including the function test of each part, and confirming the heat shielding function of the shielding plug. ing.

The terminals of these thermocouples are pulled out to the outside through openings provided in the upper fixed plug, but when the terminals of dozens of mocouples are pulled out from the upper fixed plug through separate openings, their heat shielding function is reduced. The radiation shielding function will be significantly reduced.

In order to eliminate such drawbacks, the present inventors provided a thermocouple plug on the lower fixed plug, gathered the lead wires of the many thermocouples arranged in each part into the thermocouple plug through the thermocouple well, and The lead wire of each +f-mokatsu pull is connected to the external lead wire through a cable penetration placed on the opposite side via a support, and the thermocouple plug is filled with a shielding body such as a steel ball to block neutrons. We devised a shielding plug system that provides shielding.

However, between the shielding plug bags configured in this way, the remaining space inside the thermocouple plug contains the cover scum activated by neutrons generated within the reactor, as well as the fission products and vaporized sodium contained therein. , installation of additional thicker and heavier shielding outside the cable penetration and its supports.
There was the inconvenience of having to do so.

[Objective of the Invention] The present invention was made based on the above-mentioned circumstances, and has a small size, a pumice stone, and a simple structure, and has an advanced radiation shielding function, and also has an advanced radiation shielding function by reducing thermal stress. An object of the present invention is to provide a shielding plug device having a function of supporting heavy objects.

[Summary of the Invention] That is, the shielding plug device of the present invention includes a hollow upper fixing plug that is fixed to the upper end opening of the reactor vessel and supports the C-rotary plug and onboard equipment, and a hollow upper fixing plug that is provided along the lower surface of the upper fixing plug. a lower fixed plug provided on the lower surface of the cooled gas flow case; and a thermocouple plug provided on the upper part of the lower fixed plug by cutting out a portion of the cooled gas flow case. , a cable penetration attached to a support installed on the upper fixing plug, and a sealing material for preventing cover gas overflow provided between the cooling gas flow case and the lower fixing plug.

1゛Embodiment of the Invention] The details of the present invention will be described below with reference to an embodiment shown in the drawings.

FIG. 1 shows a schematic configuration of a fast breeder reactor equipped with a shield plug device of the present invention, FIG. 2 shows a cross section along the line TI-■ in FIG. 1, and FIG. -b shows a cross-section of an embodiment of the lug device; In the figure, reference numeral 1 denotes a reactor vessel, and inside this reactor vessel 1, a reactor core 2 is provided, and a primary coolant 3 such as liquid sodium is accommodated. A fixed plug 4 is fixed to the upper opening of the reactor vessel 1, and a rotary plug 5 is rotatably attached to an eccentric position of the fixed plug to close the upper opening of the reactor vessel 1. A core upper mechanism 6 is attached to the rotating plug 5 so as to penetrate therethrough.

The fixed plug 4 is composed of an upper fixed plug 7 and a lower fixed plug 8. The upper fixing plug 7 has a main binding function and has a radiation shielding function and a heavy object support function, and the lower fixing plug 8
It mainly has a C heat shielding function.

The upper fixing plug 7 is attached to the J: sea urchin, outer shell 9 also shown in FIG.
The inner shell 10 is eccentrically arranged inside, and the upper and lower ends of the outer WA 9 and the inner shell 10 are connected by an upper plate 11 and a lower plate 12 to form a hollow annular body. Furthermore, as shown in FIG.
Attach a plurality of guide pipes 1/I that penetrate the bottom between 2,
A neutron shield 15 made of granular polyethylene is filled around them.

As shown in FIGS. 1 and 3, a cooling gas flow case 16 is attached to the lower surface of the upper fixing plug 7. As shown in FIGS. A thermocouple plug 17 is installed on the upper surface near the periphery of the lower fixed plug 8 located below the cooling gas flow case. A portion of the cold gas flow case 16 and the lower plate 12 of the upper fixing plug 7 are cut out to form a through hole 18 into which a thermocouple plug 17 is inserted.

A plurality of thermocouple wells 20 containing thermocouples 19 drawn from each part of the fixed plug are bundled near the center of the thermocouple plug 17, and their upper ends pass through the lower plate 12 of the upper fixed plug 7. extends upward. The remaining space within the thermocouple plug 17 is filled with a shielding method 21 of a neutron shield made of steel balls or the like.

Between the lower fixing plug 8 and the cooling gas flow case 16, and the cooling 7. (The space between the gas flow case 16 and the lower plate 12 is hermetically sealed near the outer periphery of the through hole 18 by ring-shaped sealing materials 22 and 23, respectively.

A flanged sleeve-shaped support 24 is airtightly fixed to the upper end of the through hole 18 of the lower plate 12, and a cable penetration 26 is airtightly fixed to the upper end of this support via a sealing member 25. .

The tip of the thermocouple 19 protruding from one end of the thermocouple well 20 is connected to a lead wire 27 on the outside of the support 24 via a conductor in the cable penetration 26. This lead wire 27 is led out from the upper fixing plug 7 through an opening provided in the upper plate 11 of the upper fixing plug 7.

[Effects of the Invention] As described above, the shielding plug device of the present invention includes a hollow upper fixing plug that is fixed to the upper end opening of the reactor vessel to support the rotating plug and onboard equipment, and a lower surface of the upper fixing plug. A cold gas flow case provided along -C, a thermocouple plug supported on the lower fixed plug on the lower surface thereof, a cable penetration provided on the upper fixed plug above the thermocouple plug, and It is characterized by comprising a cooling gas flow case and a sealing material provided between the lower fixing plug. Therefore, as the operating time of the reactor increases, the cover gas activated by neutrons generated in the reactor core, and the fission products contained therein, rise upward to the cooling gas flow case of the shielding plug. radiation levels to the upper fixed plug are significantly reduced. As a result, it becomes necessary to provide an additional thick-walled and heavy shield on the support. In addition, maintenance and inspection of each weighing device installed on the top surface of the shielding plug becomes easier, which increases the safety of the reactor, significantly improves the operating rate, and reduces plant costs.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of a fast breeder reactor equipped with a shielding plug device according to an embodiment of the present invention, Fig. 2 is a sectional view taken along the Tr-IT line of Fig. 1, and Fig. 3 is a diagram according to the present invention. FIG. 3 is a longitudinal sectional view showing an embodiment of the shielding plug device of FIG. 1・・・・・・・・・Reactor vessel 4・・・・・・
・・・・・・Fixed plug 5・・・・・・・・・Rotating plug 6・・・・・・・・・Core upper mechanism 7・
・・・・・・・・・・・・-1 Partially fixed plug 8...
・・・・・・Lower fixing plug 9・・・・・・・・・
...Outer shell 10...Inner shell 11..."Second plate 12...Bottom Plate 13... Reinforcement rib 14...
...... Guide tube 15 ...... Neutron shield 16 ...
......Cooling gas flow case 17...
・・・・・・Thermocouple plug 18・・・・・・
......Through hole 19...Thermocouple 20...
・・・・・・・・・Thermo couple well 21...
......... Shielding method 22.23... Sealing material 2/I... Support body 25...
・・・・・・Seal member 26・・・・・・・・・・・・
・Cable penetration 27・・・・・・・・・・
・Lead line agent dialect 1ri 10 rules Kensuke Chika (
1 idiot) 11- Figure 1, Ward 2i, Figure 3

Claims (2)

[Claims] (1) A hollow upper fixed plug that is fixed to the upper end of the reactor vessel and supports the rotating plug and onboard equipment;
A cooling gas flow case provided along the lower surface of this upper fixed plug, a lower fixed plug provided on the lower surface of this cooling waste flow case, and a cooling gas flow case provided above the lower fixed plug. A thermocouple plug provided with a partial cutout, a cable penetration attached to a support installed on the upper fixing plug, and a sealing material installed between the cooling gas flow case and the lower fixing plug to prevent gas from rising. A shielding plug device comprising: (2) The shielding plug device according to claim 1, wherein a sealing material is disposed between the upper fixed plug and the cooling gas flow case.