JPS6058589A - Rotary shielding plug for 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 (Technical field to which the invention pertains) The present invention relates to a rotary shielding plug for a nuclear reactor in a rotary plug type noul mechanism, which is one of the fuel exchange systems of a fast breeder reactor.

[Prior art and its problems]

The rotating shield plug is one of the fuel exchange systems for fast breeder reactors, and although it remains fixed during steady operation of the reactor, it rotates and functions during fuel exchange.

FIG. 1 shows a schematic cross-sectional view of a conventional single-rotation plug installed at the top of a reactor vessel of a fast breeder reactor. As shown in the figure, a seal portion is provided in the annular space 13 of the sliding surface between the rotating plug IO and the fixed glove 11. Note that A and B indicate the center of the rotating plug and the center of the upper part of the furnace vessel, respectively.

Figure 2 shows an enlarged view of the seal part.
It has a double seal structure with X seal alloy tube seal. That is, the freeze seal alloy part includes a seven-lease seal alloy 15 provided so that the partition plate 14, which is a part of the rotating plug 10, is immersed therein, and an alloy storage container 16 that stores the freeze seal alloy 15). 84 was completed,
On the other hand, the tube seal portion is located above the freeze seal alloy portion, and two opposed tube seals 17 are attached thereto, and lubricating oil 18 is supplied between these tube seals 17. Note that an oil receiver 19 is provided below the tube seal to collect leaked oil.

The problem with the seal structure constructed in this way is that the oil in the tube seal part may leak out due to damage to the tube 17, causing a situation where liquid and vaporized oil mixes into the alloy. . That is, if oil gets mixed into the seal alloy, there is a risk that reactants will be generated in the alloy due to the stirring effect of the partition plate 14 as the rotating plug 10 rotates, and if oil is generated, these reactants may have various adverse effects. There is a possibility that For example, reactants may be present in the alloy or at the contact surface between the alloy and a container housing the alloy, impairing the inherent sealing performance of the alloy, and rotational torque of the partition plate 14 due to the presence of reactants in the alloy. It is assumed that an increase in the amount of water may cause problems with the rotation function of the rotary plug.

In order to prevent these troubles, the conventional structure is to provide an oil receiver 19 below the tube seal to collect leaked oil.

When oil leaks from the tube seal quietly flows out, the oil accumulates in the oil receiver 19, so that it is possible to prevent oil from getting mixed into the alloy.

However, if the oil under pressure leaks violently into bubbles due to a major break in the tube, it is highly likely that the oil will overflow from the oil receiver 19 and get mixed into the alloy. Even if such sudden oil leakage occurs, it is necessary to take measures to prevent oil from getting mixed into the alloy.

[Purpose of the invention]

The present invention has been made in view of the above points, and it is hypothetical that when the lubricating silicone oil used in the tube seal part mixes into the seal alloy, reactants are generated. It is an object of the present invention to provide a rotary cover plug for a nuclear reactor having a structure that prevents this from occurring and also prevents damage to the sealing function of the seal alloy and the function of the rotary plug.

[Summary of the Invention J The present invention is a seal provided at the open end of a pressure vessel, between the annular sliding portion of the fixed plug and the rotating plug, using a seal alloy and a tube seal. A rotary shielding plug for a nuclear reactor that can prevent oil from entering the alloy by providing an oil leakage prevention plate supported by an elastic body between the seal alloy part and the tube seal part.

〔Effect of the invention〕

According to the present invention, even if oil suddenly leaks from the tube seal, it is possible to prevent the oil from getting mixed into the alloy, thereby eliminating the possibility of interfering with the rotating function of the rotary plug.

[Embodiments of the invention]

Embodiments of the present invention will be described using the drawings. An embodiment of the present invention is shown in Fig. 1, as shown in Fig. 3.

A characteristic difference from FIG. 2 is that grooves 23 are provided on the rotating plug side 10 and the fixed plug side 11 directly below the tube seal portion. It has a structure in which elastic bodies 21 are attached to some of these grooves 23 and oil leakage prevention plates are suspended from these elastic bodies 21.

The functions of the present invention having these structures are as follows. If the lubricating oil 18 in the tube seal section under pressure suddenly leaks due to tube breakage, etc., the oil leakage prevention plate 22 is pushed down and comes into close contact with the groove 23, causing the oil to leak into the seal alloy. It can completely prevent leakage in any direction.

Next, other embodiments of the present invention will be described.

[Another Actual Gun Example 11] Fig. 4 shows an example in which an oil leakage prevention plate 22 is provided at an intermediate position between the seal alloy part and the oil receiver 19, that is, grooves 23 are provided in the rotating plug ψl11O and the fixed plug 1ll11. Some of the elastic bodies 21 are removed from these grooves, and an oil leakage prevention plate 22 is connected to these elastic bodies 21. The oil that has passed through the oil receiver 19 in a rapid movement pushes the oil leakage prevention plate 22, causing -C(
823 and Q are to be brought into contact with each other to prevent the metal from flowing into the sealing alloy.

[Other Example 2] Figure 5 shows the rotating plug @IO directly below the tube seal part.
This is an example in which a plate 24 and a stop plate 25 are provided, and an oil leakage prevention plate 22 supported by the elastic body 21 is installed between them.

[Other Embodiment 3] FIG. 6 shows an example in which the same structure as in Embodiment 3 is provided at an intermediate position between the 7-1 metal alloy part and the oil receiver 19.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of a conventional rotating shield plug, FIG. 2 is a partially enlarged sectional view of FIG. Enlarged sectional view,
4 to 6 are enlarged sectional views of main parts showing other embodiments of the present invention. 10...Rotating plug 11...Fixed plug 12...
・Seal part 13... Annular space part 14... Partition plate
15... Freeze seal alloy 16... Alloy storage container 17... Tube seal 18... Lubricating oil
19...Oil receiver 20...Reactor interior space 21.
...Elastic body 22...Oil leakage prevention plate 23...Groove 24...Elastic body mounting plate 25...Stopping plate Fig. 1//) Fig. 2 Fig. 3 Fig. 1/'1 No. 4 figure

Claims (1)

[Claims] In a rotating shielding plug for a nuclear reactor, which is provided at the R port end of a pressure vessel and has a sealing mechanism using a seal alloy and a tube seal between the annular walls of the sliding part of the fixed plug and the rotating plug, the seal alloy part and the tube seal part A rotary shielding plug for a nuclear reactor, comprising an oil leakage prevention plate supported by an elastic body in the middle thereof.