The device and method of administration plugs in the pipe shell nuclear fuel rod

 

(57) Abstract:

End plug is inserted in the pipe end of the shell after it uploads the nuclear fuel tablets. During the operation load of tablets clutch holder and plugs protect the outer surface of the tube shell and the cap from contamination. The clutch is mounted on the end of the pipe, is introduced into the soft seal located in the wall of the sealing zone. The plug is located in the recess of the holder, is inserted in the pipe end by moving on a sliding fit of the holder through the clutch. When removing the pipe coupling and the holder is held in the seal. 2 S. and 6 C.p. f-crystals, 2 Il.

The invention relates to the loading of nuclear fuel tablets in the pipe shell for the formation of a nuclear fuel rod of a nuclear reactor.

In particular, the present invention relates to the introduction of a trumpet shell end caps after loading in the pipe shell set of nuclear fuel tablets, which are made of a mixed oxide fuel consisting of a mixture of uranium dioxide with plutonium dioxide.

Due to the radiological hazards associated with working with pellets of nuclear fuel containing plutonium, tablets izgotovlivajut is Itachi in the pipe shell, outside the sealing zone, the end of the pipe through which the injected tablets passes into the zone of sealing. In the end part of the tube becomes contaminated. This causes the need for a process of decontamination of the rod, which is undesirable, because it increases production costs.

The aim of the present invention is elimination of the need for decontamination of the rod after the load operation of the nuclear fuel tablets.

According to one distinctive feature of the present invention is provided a device for insertion of the end caps to the pipe shell nuclear fuel rod after loading in the shell specified in the pellets of nuclear fuel. This device contains mounted for movement on one end of the pipe shell coupling, which may be on a sliding fit to be installed in soft seal holder having a recess for installation in it of the end caps with the aim of closing the one end of the pipe shell, which can slide in the sleeve, so that when it is moved through the sleeve end plug is inserted into the specified one end of the tube envelope, which design is carried out in the seal.

Preferably, the clutch had an inner seat area containing a portion of reduced diameter extending from one end of the coupling and adapted to fit on the end of the pipe shell.

The landing surface is preferably passes from the specified one end of the coupling to the inner end surface, which coincides with the end surface of the pipe shell.

The landing surface may be press fit on the pipe shell.

In a preferred embodiment of the present invention the end cap has a head portion with an end surface and a peripheral surface, and the depth of the notches in the holder sufficient to surround an end surface and a peripheral surface.

It is preferable that was provided retaining means for retaining the sleeve and holder in soft seal after removing the pipe shell.

Soft seal can be a sphincter seal type, with many elastic ring adapted to compress the clutch.

According to the next distinctive feature of the present invention is provided a method of introduction of the end caps into the tube of the OIV, contains the following steps: install the coupling on one end of the pipe shell, the introduction of the coupling in soft seal, the introduction of the holder in the coupling, and the holder has a closed recess, containing end cap that is inserted into the specified one end of the tube sheath after insertion of the holder in the sleeve, and removing the pipe shell inserted in her end cap, leaving the sleeve and the holder in the seal.

Preferably, the method includes another step of the shift clutch and the holder of the seal coupling installed on the new pipe shell fuel rod during the next boot sequence pills.

Below is a description of embodiments of the present invention with reference to the accompanying drawings.

Fig. 1 is a diagram of an apparatus for loading nuclear fuel tablets in the pipe shell fuel rod;

Fig. 2,a,b,c,d,e illustrates the successive stages of the boot sequence of the tablets.

According Fig. 1 cylindrical pellets of fuel 1, which is made of a mixed oxide fuel containing uranium dioxide and plutonium dioxide, arranged in series in the area hermet the pipe shell fuel rod 4, located outside the sealing, to form a nuclear fuel rod.

In the area of the seal 2 tablets 1 are arranged end to end in the hole provided in the bearing pallet 5. The tray 5 has a series of parallel holes, which are formed of multiple rows of pellets of nuclear fuel. From the tray 5, the number of tablets 1 pulled the weighing channel 6 tappets 7 associated with the moving mechanism 8. Stop feeding 9 restricts the movement of the walking tablets until then, until it formed a set containing the required number of tablets. When the set reaches the required length, which is determined by weighing equipment associated with the weighing channel, he moved to the vibration table 10. This can be accomplished by vibration of the weighing channel 6.

Outside seal 2 tube sheath 4, provided with a lower end cap 11, is aligned with a set of tablets. Roaming clutch 12, napressovyvaniya at the end of the pipe shell, preferably made of plastic material and mounted on a sliding fit in soft sphincter seal 13. Sphincter seal 13 is attached to the mounting Board 14, kotiranta 16 in the mounting circuit Board, the end surface 17 is located opposite can glide back of the locking plate 18. Sphincter seal comes with several rubber rings 19, each of which is divided into sectors. When the clutch 12 passes through the center of the seal rings 19 are deformed but remain positive sealing contact by apresski on the clutch. The clamps 20 are designed for easy holding tube sheath 4 on the spot, and limit stopper 21 slides on the lower end cap 11 to prevent longitudinal movement of the pipe.

In the process, vibration table 10 and the pipe shell 4 are subjected to vibration by connecting with dual mode vibrator (not shown). It makes a set of tablets to move along the guide pipe 22, forming a single unit with table 10. The end of the pipe 22 has the shape of a semi-circular channel 23, which holds the tablet through the sleeve and enters it into the tube sheath 4. Preferably, the tube 22 is made of a material that is compatible with tablets of nuclear fuel, a suitable example of which can serve as stainless steel or zirconium alloy. Tablets are moved along the tube sheath 4 up until the first tablet will not face niblock is purely illustrative and may include other systems, containing, for example, a soft support surface or pushers for the introduction of tablets.

After retracting the stop vibrating table 10 and guide tube 24 is used for floating holder stub 24 (see Fig. 2c) for insertion of the upper end plugs 25 and a pressure spring 26 in the end of the tube sheath 4. Preferably, the holder of the stub 24 is made of a plastic material. Reference Board 27 are designed to be installed behind the clutch 12, the clamps 20 opens and retracts limit stopper 21. Trumpet shell 4 is extracted, while the clutch 12 and the holder of the stub 24 is limited to the support plates so as to be clamped in the sphincter seal 13. Retrieved trumpet shell passes through the machine for roller welding circumferential seams 28, which makes circular welding for connecting the upper end of the stub 25 with the pipe shell. Subsequent extraction pipe shell enters the upper end of the plug 25 in the device fill with helium and welding 29, which is pumped into the pipe helium through a small hole 30 (see Fig. 2c) in the cap and fill the hole with weld material.

Now with reference to Fig. 2,a,b,c,d,e consider the sequence for the sliding sleeve 12 at the other end. Coupling at one end has a seat 31 of reduced diameter, which is planted on the press fit on the end of the tube sheath 4. Thus, the outer end surface of the tube sheath 4 closed mounting seat 31 and protected from radioactive contamination of the environment sealing zone 2.

As the tube sheath 4 is moved in the direction of the arrow A, the clutch 12 is engaged with the clutch 12a containing the holder stub 24a, which was kept in a sphincter seal 13 after the previous load operation of the tablets. When the locking Board 18 in the retracted position a new clutch 12 pushes the clutch and site holder stub from shankarnagar seal 13 in the sealing area 2 (Fig. 2b). Since the new clutch 12 is in the sphincter seal 13 before it will be deleted previously used the clutch and the holder of the stub, the leakage of radioactive substances from the zone of the seal is eliminated. The retaining Board 18 is then lowered to provide a place for the end surface 17 of the coupling 12.

In Fig. 2c shows a semicircular end channel 23 of the guide pipe 22 passing into the coupler 12. When vibration of the vibration table 10 and the tube sheath 4, as regarded the new tablet will not collide with the lower end cap 11. When a set of tablets will be loaded into the tube sheath 4, table 10 and guide tube 22 disposed ago.

The upper end plug 25 with a pressure spring 26 is shrinked then at the end of the tube sheath 4 by using a floating holder stub 24. Holder stub has a cylindrical shape and an outer diameter that is installed in the sleeve 12 in a sliding fit. Blind hole 35 is drilled along the longitudinal axis of the holder stub 24 has a recess with an enlarged diameter 36 at its front end. Excavation depth sufficient to fully receive the head part 37 of the upper stub 25. It is especially important to ensure that the end surface 38 and the peripheral surface 39 of the head part 37 were completely closed in order to protect them from possible contamination. On the front end of the upper stub 25 has a shoulder 40 which provides a seat for a pressure spring 26. After retracting the stop vibrating table 10 and guide tube 22 can be provided for use in the area of the sealing remotely controlled manipulator (not shown) to push the holder stub 24 through the sleeve 12 and pressout upper cap 25 at the end of the tube sheath 4. When the is serves to hold the pellets of nuclear fuel for subsequent manipulation and transportation of nuclear fuel rod so that so they are not damaged.

As shown in Fig. 2d, the support Board 27 is shifted inside to be behind the clutch 12 while open the clamps 20 and limit stopper 21 is allocated back from the bottom of the stub 11. After removing nuclear fuel rod coupler 12 and the holder stub 24 remain trapped in the sphincter seal 13 (Fig. 2e). Then the nuclear fuel rod passes through the machine 28 for welding end caps and fill genius, as well as through welding device 29 for final Assembly of nuclear fuel rod. Then the above sequence of operations is repeated for the next nuclear fuel rod.

As you can see, during the operation of loading tablets no external surface of the pipe shell and the upper end of the stub won't be open to the radioactive environment contained in the sealing area. This eliminates the need for costly process of decontamination of a nuclear fuel rod.

1. The device for insertion of the end caps to the pipe shell nuclear fuel rod after loading of nuclear fuel tablets in the specified pipe obolochek that the coupler can on a sliding fit to be installed in soft seal, holder having a closed hollow for the accommodation therein of the end caps for closing the one end of the pipe shell, sliding on a sliding fit in the sleeve, so that when it is moved through the sleeve end plug is inserted in the end of the pipe shell, and retaining means for holding the sleeve and holder in soft seal when removing the pipe shell from the clutch.

2. The device under item 1, characterized in that it has an internal landing surface that includes a portion of reduced diameter extending from one end of the coupling, and the landing surface is adapted to fit on the specified one end of the tube shell.

3. The device according to p. 2, wherein the landing surface passes from the specified one end of the coupling to the inner end surface, which coincides with the end surface of the pipe shell.

4. The device according to p. 2, wherein the landing surface is press fit on the pipe shell.

5. The device under item 1, characterized in that the end plug has a head portion with an end surface and a peripheral surface, and this recess has a depth sufficient for future items wherein the soft seal includes a sphincter seal, with many of elastic rings, clutch jaws.

7. The method of introduction of the end plugs in the pipe shell nuclear fuel rod after it uploads the nuclear fuel tablets, characterized in that it comprises the following steps: install the coupling on one end of the pipe shell, the introduction of the coupling in soft seal, the introduction of the holder in the coupling together with contained in the end cap, which is inserted into the specified end of the pipe shell with the introduction of the holder in the sleeve, removing the pipe shell with end cap, entered it, and install the locking means in position to hold the sleeve and the holder in soft seal when removing the pipe shell from the clutch.

8. The method according to p. 7, characterized in that conduct the next stage of the movement of the coupling and the holder of the seal coupling installed on the new pipe shell nuclear fuel rod during the next boot sequence pills.

 

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