JPS6023951B2 - Shroud head bolt rotation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shroud head bolt rotating device for automatically rotating a shroud head bolt in a boiling water nuclear reactor by remote control.

Generally, in a boiling water reactor, a columnar fuel assembly 2 is housed inside a reactor pressure vessel 1, as shown in FIG. and a core support plate (not shown). Said shroud 3
At the top of the shroud head 5, there is a bowl-shaped shroud head 5 which is covered with its concave portion facing the shroud 3 in order to separate the two-phase flow of steam and water generated in the reactor core, and welded to the convex portion of the end plate of the shroud head 5. A steam/moisture hatching device 8 comprising a plurality of standpipes 6 fixedly installed with a steam/water broiler 6, etc., and a steam/moisture scale device 7 attached to the tip of each standpipe 6.
is located.

In the steam/moisture broiler device 8 configured as described above, the steam-water mixture generated in the reactor core passes through the stand pipe 6, enters the steam/moisture broiler 7, and is separated into steam and water.

When the fuel assembly 2 is replaced or periodically inspected, the steam/moisture chick device 8 is removed to the outside of the reactor pressure vessel 1 so as not to interfere with the replacement or periodic inspection of the fuel assembly 2.

For this reason, the shroud head 5 of the steam/moisture chick device 8 and the shroud 3 are locked by the shroud head bolts 9 and have a structure that allows them to be separated.

That is, as shown in FIG. 2, which is an enlarged view of part A shown in FIG. has been done. Similarly, a flange 12 is provided protruding from the closed portion of the shroud head 5, and a screw hole 13 is bored in this flange 12 at a position corresponding to the screw hole 11 bored in the flange 0 of the shroud 3. ing. A shroud head bolt 9 is screwed through the screw holes 11 and 13, so that the shroud head 5 is locked to the shroud 3.

The bolt head 14 of this shroud head bolt 9 is configured to be located near the upper end of the steam/moisture chick device 8 so that the shroud head port 9 can be rotated from the top of the steam/moisture chick device 8. head bolt 9
Since the bolts are considerably longer than ordinary bolts, they are supported in the radial direction by brackets 15 and 16 attached to the stand pipe 6 and the steam separator 7, respectively. Subordinate, shroud 3 of steam/water separation device 8
Such rotation of the shroud head bolt 9 during attachment to and detachment from the shroud head bolt 9 has been done manually using a wrench or the like held by the operator.

However, since a large number of shroud head bolts 9 are generally used, 36 in the above-mentioned boiling water reactor, it is difficult to rotate the shroud head bolts 9 one by one manually. This has the disadvantage of lowering the operating rate of nuclear power plants.

Furthermore, the upper part of the steam/moisture brochure device 8 in the reactor pressure vessel 1 where the work is performed is a highly radioactive area, and there is a disadvantage that the workers are exposed to radiation.

The present invention has been made to eliminate such conventional drawbacks, and includes a plurality of sockets that are iron-mounted to the shroud head bolt and rotate the same, and each of these sockets is held at a position corresponding to the shroud head bolt. Provided is a shroud head bolt running device for a boiling water reactor, characterized in that it is comprised of a support member for rotating the socket, a drive mechanism for rotationally driving the socket, and a remote control mechanism for remotely controlling the drive mechanism. This is what I am trying to do.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the drawings and examples thereof. In FIG. 3, the shroud head bolt rotating device includes a cross-shaped support member 17 and a cross-shaped support member 17.
four wrench mechanisms 18 fixed to the tip of each arm;
The main portion is composed of a remote control mechanism (not shown) that remotely drives the wrench mechanism 18.

As shown in FIG. 4, the wrench mechanism 18 includes a socket 19 attached to the shroud head bolt 9 to rotate it, a bearing 20 that supports the rotation of the socket 19, and a bearing 20 fixed to the terminal end of the socket 19. spur gear 21
The motor 23 includes a driving spur gear 22 that meshes with the driving spur gear 22, and a motor 23 that has the driving spur gear fixed to a rotating shaft.

Since the motor 23 is used in a nuclear pressure vessel filled with steam, an air motor or a water pressure motor is used. It is located at 17.

This wrench mechanism 18 also includes screw holes 1 bored in the flanges 0 and 12 of the shroud 3 and the shroud head 5.
The socket 19 is fixed to the support member 17 so as to be located on the same circumference as the sockets 1 and 13.

The shroud head bolt rotating device constructed as described above is used in the following manner.

That is, the shroud head bolt rotation device is transported by a crane or the like above the steam/water separation device 8 in the reactor pressure vessel 1, and is horizontally moved so that the socket 19 of the wrench mechanism 18 is located above the shroud head bolt head 14. After that, the shroud head bolt rotation device is moved vertically downward, and the socket 19 is iron-fixed to the shroud head bolt head 14.

Next, the motor 23 is driven by operation of a remote control mechanism (not shown), and the socket 19 is driven via the drive-side spur gear 22 and the spur gear 21.

As a result, the shroud head bolt 9 is rotated, and the shroud 3 and the shroud head 5 are locked or unlocked.

In addition, in the boiling water reactor of this embodiment, 36 shroud head bolts 9 are arranged at the same pitch on the same circumference, so using the bolt rotation device of this embodiment, , In order to rotate all 36 shroud head bolts 9, the number of shroud head bolts 9, 36, divided by the number of sockets 19, 4, is the number of times.
In other words, it is sufficient to repeat the above operation nine times.

As described above, according to the shroud head bolt rotation device of the present invention, the shroud head bolt can be rotated by remote control. will be resolved. Further, since a plurality of shroud head bolts can be rotated at high speed in one set-up, work efficiency is significantly improved.

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional view schematically showing the steam-water separation device portion of a boiling water reactor, and Fig. 2 is an enlarged cross-sectional view partially enlarging the locking part of the shroud and shroud head in Fig. 1. 3 is a plan view showing an embodiment of the shroud head bolt rotating device of the present invention, and FIG. 4 is a partial vertical sectional view of the wrench mechanism in FIG. 3. 1... Reactor pressure vessel, 2... Fuel assembly, 5
・…．・Shroud head, 8... Moisture chick device, 9.... ...Shroud head bolt, 17...
...Supporting member, 18. ...wrench mechanism, 19...
...Socket, 23...Motor. Suncho Zuta 2 Tsuruta 3 Zuta 4

Claims (1)

[Claims] 1. In a reactor internal support structure that supports the fuel assembly housed inside the reactor pressure vessel and is composed of a shroud, an upper grid plate, and a core support plate, on the top of the shroud. In order to separate the two-phase flow of steam and water generated in the reactor core, the shroud head is fitted into the shroud with its concave portions facing each other, a plurality of standpipes are installed in the convex portion of the head plate of the shroud, and each It includes a steam and water separator that is composed of a steam and water separator that is attached to each end of a standpipe, and also includes a cross-shaped support member and a plurality of wrench mechanisms that are fixed to the ends of each arm of this support member. and a remote control mechanism for remotely driving the wrench mechanism, the wrench mechanism comprising a socket fitted into a shroud head bolt to rotate it, a bearing for supporting rotation of the socket, and a bearing for supporting the rotation of the socket. a second driving gear meshing with a first gear fixed to the terminal end of the socket;
and a drive motor that fixes the second gear to a rotating shaft, and the wrench mechanism is configured so that the socket is located on the same circumference as a screw hole drilled in the flange of the shroud and the shroud head. A shroud head bolt rotation device, characterized in that the shroud head bolt rotation device is fixed to the support member so as to.