JPH02228593A - Installation of equipment structure in nuclear reactor - Google Patents

Abstract

PURPOSE:To suppress an incovenience within the minimum level in a construction of a nuclear reactor and to shorten a construction period by installing recirculation pumps after an installation of housings of control rod drive mechanisms and then by installing upper grid plates. CONSTITUTION:For a construction of a nuclear reactor, after an installation of a shroud 2 and a reactor core support plate 3 is performed by turns, installation of a housing 7 of a control rod drive mechanism, a feed water sparger 9, a piping 10 of a core spray and so on, are carried out in parallel. After that, an internal recirculation pump 5 is installed and then an upper grid plate 4 is also installed. During the installation of the recirculation pump 5, both works inside and outside a nuclear reactor pressure vessel 1 can be carried out simultaneously. For an installation of equipment structures inside the reactor, a pump opening 6 for fixing the recirculation pump 5 and a housing opening 8 for fixing the housing 7 of the control rod drive mechanism, can be effectively utilized for laying cables and hoses, and consequently a shortening of a construction period can be attained.

Description

Detailed Description of the Invention (Objective of the Invention) (Industrial Application Field) The present invention provides a method for installing a recirculation pump built into a reactor and various other internal equipment structures during the construction of a boiling water reactor. Regarding.

(Prior Art) A boiling water reactor (BWR) having a conventional external recirculation loop as shown in FIG. This shroud 23 is provided with a core support plate 24 at its lower part, and an upper lattice plate 25 is arranged at its upper part.

In addition, a plurality of jet pumps 26 are disposed at a required pitch in the circumferential direction in the annular gap between the outer circumferential surface of the shroud 23 and the inner circumferential surface of the reactor pressure vessel 22. and tll till rod drive mechanism is inserted and fixed into the tII and III rod drive drive mechanism housing 2 housing openings 28. And upper lattice plate 2
Above the water supply sparger 29, the core spray pipe 3
0 is provided in the reactor pressure vessel 22.

In such a boiling water reactor, the various reactor internal structures described above are installed in accordance with the conventional procedure shown in FIG.

That is, first, the jet pump 26 and the shroud 24
are installed in the reactor pressure vessel 22, and then the reactor core support plate 24 disposed inside these is installed.

Align the center position with the core support plate 24, and then
l Install the m-ray drive mechanism housing 27.

On the other hand, in parallel with these, above the shroud 23,
The water supply sparger 29 and core spray piping 30 are installed.

At this time, workers and the like access the work above the shroud 23 from the upper opening of the reactor pressure vessel 22. On the other hand, the installation work for lower reactor internals such as the control rod drive mechanism housing 27 is accessed by going in and out of the recirculation nozzle 21, and not only is the equipment and workers accessed, but cables and hoses can also be accessed. Furthermore, after the construction of these lower reactor internal structures was completed, external piping for recirculation was connected to the recirculation nozzle 21. In this way, by dividing up various construction works from above and below, access for construction work was divided into two parts.

Further, the installation of the upper lattice plate 25 cannot be carried out in parallel because its work area is close to the upper work area of the shroud 23. Furthermore, after the upper grid plate 25 is installed, it becomes difficult to access the upper surface of the core support plate 24, and the work on the lower part becomes very troublesome, so it was decided to install it after these are completed.

(Problem to be Solved by the Invention) However, in a boiling water reactor equipped with a built-in reactor recirculation pump (RIP), since there is no recirculation nozzle 21 described above, it is difficult to work inside this recirculation nozzle 21. personnel cannot enter or exit.

Therefore, access for workers is of course limited to the upper frontage of the reactor, and there is also the problem that the routes for hand cables, hoses, etc. are also thick (11).

Therefore, the present invention was created in view of the existing circumstances as described above, and aims to minimize the construction inconveniences that occur in boiling water reactors that employ a built-in recirculation pump. The aim is to reduce construction costs and shorten the construction period, and to provide optimal installation procedures for various types of reactor internal equipment structures.

(Structure of the Invention) (!!Means for Solving the Problem) In order to achieve the above-mentioned object, the present invention provides an internal equipment structure of a boiling water reactor having a reactor built-in recirculation pump. In the installation method of the article, the ill III rod drive drive mechanism with housing is characterized in that the recirculation pump is installed thereafter, and then the upper grate plate is installed.

(Function) In the method for installing a nuclear reactor internal equipment structure according to the present invention, the pump opening for fixing the recirculation pump and the housing opening for fixing the control movement mechanism housing are connected to construction cables, hoses, etc. It can be used most efficiently for routing etc.

Additionally, recirculation pumps can be installed during construction at a time when there will be the least disruption in terms of access for workers and the relative position of equipment.

(Example) Hereinafter, an example of the present invention will be described with reference to FIGS. 1 and 2.

The symbol @1 shown in FIG. 2 is a reactor pressure vessel, and a shroud 2 coaxially accommodated in the reactor pressure vessel 1 is provided with a core support plate 3 at an axially intermediate position.
An upper lattice plate 4 is arranged above this core support plate 3. The upper grid plate 4 and the core support plate 3 support the upper and lower parts of a plurality of fuel assemblies (not shown), respectively.

In addition, a part of the in-reactor trunk-type re-shield ring pump 5 is inserted through the bottom wall of the reactor pressure vessel 1 in the annular gap between the inner circumferential wall of the reactor pressure vessel 1 and the outer circumferential wall of the shroud 2. However, the pump n port 6 is the same port, and the atomic or built-in recirculation pump 5
A pump section is disposed inside the reactor pressure vessel 1. Furthermore, an in-core monitor and control are installed on the bottom wall of the reactor pressure vessel 1.
The rod drive mechanism housing 7, which houses the rod drive mechanism, is fixed by fitting it into the housing opening 8.

A water supply sparge v9 and a core spray pipe 1o are provided above the upper grid plate 4.

In the method of the present invention, in the reactor pressure vessel 1 in which the reactor built-in recirculation pump 5 is built in the lower part, a part of the reactor built-in recirculation pump 5 is inserted and fixed. Aperture 6, and! The housing opening 8 into which a part of the machine ring 7 is inserted and fixed is most efficiently used for routing cables, hoses, etc. for construction work. In addition, we designed the system to minimize obstacles in terms of worker access and the relative position of equipment.
The timing for installing the reactor built-in recirculation pump 5 at the time of construction is determined.

Therefore, in this embodiment, as shown in FIG. 1, after the shroud 2 installation work and the core support plate 3 installation work are performed in this order, the control rod drive mechanism housing 7 installation work and the water supply sparger core spray piping work are performed. Other installation work will be carried out in parallel.

After that, the reactor built-in recirculation pump 5 is installed, and then the upper lattice plate 4 is installed.

Therefore, the installation of the recirculation pump 5 with built-in recirculation requires work to be carried out from both the inside and outside of the reactor pressure vessel 1, and it is a condition that these can be carried out at the same time.

First, we will examine the relationship with the installation work of shroud 2 as internal work.

The shroud 2 is the largest structure inside the reactor pressure vessel 1, and the welded part with the reactor pressure vessel 1 is located close to the reactor built-in recirculation pump 5, so it is impossible to work on these in parallel. It is.

In addition, the reactor built-in recirculation pump 5 is designed to be able to be overhauled with the shroud 2 installed, and the reactor built-in recirculation pump 5 is installed first. It is advantageous to install the shroud 2 before the reactor built-in recirculation pump 5 in consideration of the complexity of curing the recirculation pump 5 and setting up the work scaffold when installing the shroud 2 in the reactor.

Incidentally, in conventional plants, the shroud 23 is installed after the jet pump 26 is installed, but this is because structurally speaking, the jet pump 26 cannot be installed after the shroud 23 is installed.

Next, the in-core monitor (ICM) and control rod section 111e
Control rod drive mechanism housing 7 that houses one structure (CRD)
The timing of installation and the installation of the reactor built-in recirculation pump 5 will be considered.

The installation of the control rod drive mechanism housing 7 must be carried out simultaneously from both the inside and outside of the reactor pressure vessel 1, similar to the recirculation pump 5. Therefore, work from the outside will ensure that the equipment, areas, etc. to be used are recirculating. Parallel work with this pump is not possible because it interferes with the installation of the pump 5.

In addition, the installation of the IIIWJ rod drive machine unit housing 7 involves a large amount of welding work inside the reactor pressure vessel 1, so it is a difficult task to prepare the cables and hoses for this work. It becomes.

Therefore, IIJI! The installation of the l-rod drive mechanism machine part 7 is carried out before the installation of the reactor built-in recirculation pump 5, and the pump opening 6 of the reactor built-in recirculation pump 5 is connected to the above-mentioned cables and hoses. It is a good idea to use it for routing etc.

The installation of the 1lIJ111 rod drive mechanism housing 7 is conditioned on the completion of the installation of the core support plate 3. To do this, it is necessary to complete the installation of the shroud 2 that supports the core support plate 3, so as shown in Figure 1, the shroud 2 is installed, then the core support plate 3 is installed, and then the control rod drive The reactor built-in recirculation pump 5 is installed after the mechanism housing 7 is installed.

Furthermore, regarding equipment installed in contact with the upper furnace wall, such as the water supply sparger 9 and the core spray piping 10, the recirculation pump 5 cannot be installed in parallel with the work inside the furnace. However, since the installation of the control rod drive mechanism housing 7 can be done in parallel with this work, it will be carried out in parallel with this work, and the installation of the recirculation pump 5 will be the previous work.

Finally, consider the installation order of the upper grid plate 4.

Since the upper lattice plate 4 itself is a device to be attached to the shroud 2, its installation is subject to the completion of the installation of the core support plate 3.

Looking at the relationship between the reactor built-in recirculation pump 5 and the upper grid plate 4, basically, the upper grid plate 4 and the reactor pressure vessel 1
Since the distance from the inner wall of the reactor to the inner wall is smaller than the diameter of the reactor built-in recirculation pump 5, several notches are provided on the outer periphery of the upper grid plate 4 through which the recirculation pump 5 can pass. The recirculation pump 5 is arranged in a predetermined pump opening 6. Therefore, it is most difficult for the reactor built-in recirculation pump 5 to pass through the narrow cutout portion of the upper grid plate 4, and this is the most difficult point in installation. In other words, the installation of the reactor built-in recirculation pump 5,
It is clear that if this is carried out prior to the installation of the upper grid plate 4, the need for the above-mentioned narrow passage work can be reduced and work efficiency can be improved.

Of course, it is necessary to verify workability during periodic inspections by performing installations similar to those used in actual operation.

In addition, at the plant construction stage, the service equipment used during periodic inspections has not yet been completed, and considering that work will be carried out underwater during periodic inspections, at this stage, the upper grid plate 4
It is considered unnecessary to make passing work a condition from the above-mentioned verification point of view.

From the above points, it is advantageous in construction work to install the reactor built-in recirculation pump 5 before installing the upper lattice plate 4.

(Effects of the Invention) According to the method of installing equipment structures inside a nuclear reactor as explained above, it is possible to minimize the route for wiring construction cables and hoses, and the need for temporary construction storage can be reduced. In addition to contributing to the quality of welding work, it is also expected to improve the quality of welding work.

In addition, unlike the periodic inspection, it is possible to carry out the most efficient work that is most suitable for completing the construction work, which is unique to the construction stage, by making it possible to install all the pieces in a period of -3.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the present invention, FIG. 1 is a work process diagram explaining the installation procedure, FIG. 2 is an installation layout diagram of the equipment structure inside the reactor, and FIG. 4 shows a conventional example, FIG. 3 is a microcosm of its installation procedure, and FIG. 4 is an installation layout diagram of the internal equipment structure of the nuclear reactor. DESCRIPTION OF SYMBOLS 1... Pressure vessel, 2... Shroud, 3... Core support plate, 4... Upper grid plate, 5... Recirculation pump,
6... Pump opening, 7... Control rod drive mechanism housing, 8... Housing opening, 9... Water supply sparger, 10... Core spray piping, 21... Recirculation nozzle opening, 22... ... Pressure vessel, 2.3 ... Core support plate, 24 ... Shroud, 25 ... Upper grid plate, 2
6... Jet pump, 27... Control rod drive mechanism housing, 28... Housing opening, 29... Water supply sparger, 30... Core spray piping. Figure 1 Representative Patent Attorneys Nori Chika Ken Shu Ken Komaru Figure 3 Figure Figure 3

Claims (1)

[Claims] In the method for installing the reactor equipment structure of a boiling water reactor with a built-in recirculation pump, the recirculation pump is installed after the control rod drive mechanism housing is installed, and then the upper grate plate is installed. A method for installing equipment structures inside a nuclear reactor, characterized by: