JPS5810159Y2 - Mounting part of simulated fuel rod - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an attachment part for attaching a so-called simulated fuel rod formed equivalent to a nuclear fuel rod to a test container.

In various nuclear reactors, prior to operation, instead of using nuclear fuel rods as actual fuel bodies, simulated fuel rods a, a, which are heated by a sheathed heater or the like, are used as shown in Figure 1. Prepare a large number of .

b... to form an assembly of simulated fuel rods, and the assembly is housed in a test container d sealed with a tube plate C to perform a temperature test, etc. It is common practice to confirm the performance and safety of the reactor in advance.

In this type of conventional test container d, in order to obtain the power source for the simulated fuel rods outside the container d, as shown in FIG. Insert the end of the rod a so that the electrode f of the end faces the outside of the test container d, and in this state, weld the casing g of the simulated fuel rod a and both ends of the sleeve e. Furthermore, at desired locations on the surface of the simulated fuel rod a,
In order to measure the temperature at the location, the measuring terminal j of the thermocouple i is fixed, and the connecting terminal of the thermocouple i is inserted through a small diameter sleeve l that is separately fixed through the tube plate C to the outside. It was pulled out and connected to a measurement system (not shown), and the end of the sleeve l was sealed with silver solder m.

However, in such a conventional structure, the sleeve l
Since the measurement terminals k of thermocouples i, which are inserted through the tube plate C and separately penetrated through the tube plate C, are fixed to the simulated fuel rods a in the test container d, the thermocouples i are not removed from the simulated fuel rod a. The simulated fuel rod a cannot be pulled out from the tube sheet C, and therefore, if even one of the many simulated fuel rods a breaks down and is to be replaced, all the simulated fuel rods must be replaced. For thermocouple a and thermocouple i, remove the tube sheet C from the test container d by cutting the welding and silver brazing m, respectively,
Then, after replacing the failed simulated fuel rod a, the tube plate C must be reinstalled and the welding and silver brazing m described above must be performed, which reduces the number of simulated fuel rods a from several dozen to several. In cases where there are as many as 100 such simulated fuel rods, replacing this type of simulated fuel rod a becomes extremely troublesome, and the same is true when thermocouple i breaks in test vessel d. there were.

The present invention has been developed to solve these conventional problems, and uses a special device to attach the thermocouple to the end of the simulated fuel rod and pull it out from the tube plate to the outside of the test vessel. Even in the event of a failure of a simulated fuel rod,
This allows only the simulated fuel rod to be removed from the tube plate and replaced without removing the thermocouple.

This configuration will be explained below based on an example shown in FIGS. 3 and 4. In the figure, 1 is a simulated fuel rod formed to approximate the characteristics of a nuclear fuel rod, and as is known, this is a simulated fuel rod. A heating wire 3 is disposed approximately on the central axis of the cylindrical casing 2 and extends across both ends thereof, and an inorganic insulating material 4 such as magnesium oxide is filled around the heating wire 3, and the heating wire 3 is filled with an inorganic insulation material 4 such as magnesium oxide. A connection electrode 5 electrically connected to the casing 2 is protruded from the end of the casing 2 to the outside, and the end is connected to the stopper 6.
It is sealed.

Therefore, in the present invention, the inner sleeve 7 is fitted to the end of the simulated fuel rod 1, that is, the end of the casing 2, and insertion holes 8, 8, . . . are inserted between the inner sleeve 7 and the casing 2. . . . and the through holes 8, 8 are formed.
・・・・・・ Temperature measuring wire such as thermocouple 9.9...
In particular, in the illustrated embodiment, a groove is provided in the longitudinal direction of the inner surface of the inner sleeve 7, and the above-mentioned insertion holes 8, 8, .
is formed.

Furthermore, the temperature measuring strips 9, 9, . . . inserted into the insertion holes 8, 8, .
... is fixed to the inner sleeve 7 by silver soldering 10 that seals the end opening of the casing 2, and its measurement terminal 11 is fixed at a desired position where the temperature of the casing 2 is to be measured. The connection terminal 12 to be connected to the system is pulled out to the end surface side of the simulated fuel rod 1.

A large number of the simulated fuel rods 1 configured in this way are bundled together via a spacer (not shown), and these are attached to the tube plate 13.
The fixing sleeve 1 is housed in a test container 14 which is hermetically closed, and the end of the simulated fuel rod 1 fitted with the inner sleeve 7 is fixed through the tube plate 13.
5, and the terminal electrode 5 is exposed from the tube plate 13 to the outside of the test container 14, but at this time, the temperature measuring wire body 9
The connection terminal 12 of is also pulled out to the outside of the test container 14,
Connected to a measurement system (not shown).

Furthermore, in this state, both end ports of the fixing sleeve 15 and the inner sleeve 7 are welded 16 in a sealed state, thereby fixing both sleeves 15 and 17 to each other. Therefore, the simulated fuel rod 1 can be replaced, etc. In this case, by melting the weld 16 and pulling out the simulated fuel rod 1 together with the inner sleeve 7 from the tube plate 13, the temperature measuring wire 9 is removed.
The simulated fuel rod 1 can be removed without removing it.

As explained above, the present invention includes the terminal of the simulated fuel rod 1,
An inner sleeve 7 is interposed between the fixing sleeve 15 and the insertion holes 8, 8 formed between the inner sleeve 7 and the simulated fuel rod 1, extending inside and outside the test container 14.・Temperature-measuring striatum 9゜9...
, and pull out the connecting terminal 12 to the outside of the test container 14 , and then weld the ends of the fixed sleeve 15 and the inner sleeve 7 facing outside of the test container 14 by welding 1 .
According to this method, by removing the simulated fuel rod 1 together with the inner sleeve 7 from the fixing sleeve 15 by cutting the weld 16, for example, Temperature-measuring striatum 9,9・
...The simulated fuel rod 1 can be easily removed without removing it, and on the contrary, a temperature measuring wire body 9゜9...... is attached to the above fuel rod. 1 can be easily installed, and therefore, in order to replace a single simulated fuel rod, there is no need to disassemble all the simulated fuel rods and remove the tube plate 13, as in the past. This makes it extremely easy to perform this kind of replacement work.

Furthermore, in addition to the above-mentioned replacement work, when assembling this type of simulated fuel rod assembly, the temperature measuring wires 9, 9... are attached to the simulated fuel rod 1 in advance, and these are attached to the inner sleeve. 7, the fuel rods 1 can be assembled into the test vessel 14 in a state where they are gathered around the fuel rods 1. Therefore, this type of assembly work can be performed more efficiently than in the past.

[Brief explanation of drawings]

Fig. 1 is a schematic longitudinal sectional side view showing an assembly of simulated fuel rods in a sideways state; Fig. 2 is a partially cutaway vertical sectional side view of essential parts showing a conventional example of the mounting part of the simulative fuel rods; Fig. 3; Figure 4 is an enlarged cross-sectional view along the line ■■-■■ in Figure 3; large cross-sectional view 1...simulated fuel rod; 7... Inner sleeve, 8... Insertion hole, 9... Temperature measuring wire, 11... Measurement terminal, 12... Connection terminal, 13...Tube sheet, 14...Test container, 15...Fixing sleeve.

Claims (2)

[Scope of utility model registration request] (1) Insert the end of the simulated fuel rod into the fixing sleeve fixed through the tube plate of the test vessel so that the end face of the fuel rod faces the outside of the test vessel, and measure the temperature of the surface of the simulated fuel rod. In the device in which the measurement terminal of the thermometer wire is fixed at the desired position, an inner sleeve is interposed between the simulated fuel rod terminal and the fixing sleeve, and The temperature measuring wire was inserted into the insertion hole formed between the inner sleeve and the simulated fuel rod end, and its connection terminal was pulled out to the outside of the test container, and the wire was further exposed to the outside of the test container. A mounting portion for a simulated fuel rod, which is formed by fixing both end ports of the above-mentioned fixed nose and inner sleeve in an airtight state by means such as welding. (2) The attachment part of the simulated fuel rod according to claim 1 of the utility model registration claim, in which the insertion hole is formed by a groove recessed in the longitudinal direction of the inner wall of the inner sleeve and the outer surface of the simulated fuel rod terminal. .