JPS629706B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for installing a nuclear reactor pressure vessel in nuclear power plant construction work.

As shown in FIG. 1, the reactor pressure vessel 5 is mainly formed of a pressure vessel main body 5A, its internal structure, and a control rod housing 5G.

This pressure vessel main body 5A is hollow and is formed of a hemispherical seat, a cylindrical part, and a lid in order from the bottom, and inside it is a recirculation system of a jet pump 5B that circulates reactor water. , a shroud 5C that encloses the reactor core in a cylindrical shape, upper and lower grate plates 5D and 5E for fixing fuel bodies to the core, and LPCI (Low
Pressure Coolant Injection System) Coupling 5F, in-core housing 5H for holding the in-core nuclear instrumentation monitor, guide rod 5J for inserting and fixing the shroud head into the shroud 5C, core spray line piping 5K for forced core cooling, inside the reactor An internal structure consisting of more than ten types of equipment is installed, such as a water supply spargeer 5L for supplying water to the tank. Further, a control rod housing 5G for inserting and holding a control rod is provided protruding from the lower seat portion of the pressure vessel main body 5A, and a drain line 5I is also provided.

Pressure vessel main body 5A, internal structure and control rod housing 5 of a nuclear reactor having such a structure
Conventionally, G etc. were installed using the following method.

In other words, the reactor pressure vessel main body 5A and its internal structures are manufactured individually at a manufacturing factory, then transported to the nuclear power plant construction site, where they are sequentially installed and completed at the construction site. Ta.

This conventional construction method will be explained with reference to FIGS. 2 and 3.

FIG. 2 is a cross-sectional view of the reactor pressure vessel main body 5A installed in the reactor containment vessel 3 of the reactor building 1. First, after the operation floor 1a on the top floor of the reactor building 1 is completed, the pressure vessel main body 5A is lifted from the operation floor 1a, and the rails 7 of the mobile crane 9, which can move horizontally, are installed. Subsequently, the mobile crane 9 is assembled on the rail 7. At the same time, inside the reactor containment vessel 3, the biological shielding wall 6 surrounding the pressure vessel main body 5A and the containment chamber internal structure 10 are installed to level the reactor pressure vessel installation foundation 4, and the pressure vessel main body 5A is Prepare for acceptance.

Next, the pressure vessel body 5A completed at the manufacturing factory
was transported by sea. It is hoisted onto land using landing and draining equipment provided at the nuclear power plant construction site, and is towed and transported to directly below the mobile crane 9 installed in the reactor building, and then erected directly below the mobile crane 9. The mobile crane hanging device 9a is fixed to the top of the pressure vessel main body 5A with bolts,
Thereafter, the winch of the mobile crane 9 is operated to lift and store the pressure vessel main body 5A into the mobile crane 9. Next, the mobile crane 9 is moved along the rail 7 to just above the reactor containment vessel 3 using a winch, and then stopped. Next, the pressure vessel main body 5A stored in the mobile crane 9 was suspended, and the base 4
Set it on top. After completing the seating, centering and fixing of the pressure vessel body 5A, the pressure vessel body 5A is
In order to install the jet pump 5B in A,
A temporary changing room 21 is provided at the top of the pressure vessel main body 5A. In the conventional construction method, internal structures are later attached to the pressure vessel body 5A that has been installed in the reactor containment vessel 3 first.
In order to work while keeping the inside of A clean, it is necessary for the worker to change into the changing room 21 the work clothes that he or she has worn from outside with clean work clothes specifically designed for working inside the pressure vessel. Therefore, in the conventional construction method, this changing room 21 must be provided.

The floor of the changing room 21 is provided with a doorway that can be opened and closed for allowing workers to enter and exit the pressure vessel main body 5A and for inserting components of the internal structure. Further, the workers used a ladder attached to the inner wall to go back and forth to the bottom of the pressure vessel main body 5A.

After the temporary construction of the changing room 21, the internal structure is installed.

That is, first, the jet pump 5B is carried into the pressure vessel main body 5A through the above-mentioned entrance and exit port, and installation work is performed. Next, the temporary changing room 21 is moved, the shroud 5C is brought in, the temporary changing room 21 is restored to its original position, and it is welded and fixed to the bottom of the pressure vessel main body 5A. Subsequently, the upper and lower structure plates 5D and 5E are carried into the pressure vessel main body 5A and assembled in the same manner as the shroud 5C. Next, a large number of control rod housings 5G and in-core housings 5H are carried into the space in the foundation 4 at the bottom of the pressure vessel main body 5A through a specially installed chute inside the reactor containment vessel 3, and then the bottom of the pressure vessel main body 5A is transported. are sequentially inserted into the pressure vessel main body 5A from the center toward the periphery, and are welded and fixed inside. These control rod housing 5G and in-core housing 5H are
Since there will be over 200 pieces in total, the construction period will be long.

After completing these tasks, remove the guide rod 5.
J, core spray line piping 5K, water supply spargeer 5L, etc. are sequentially carried into the furnace, installed, and then welded to complete the process.

The reactor internals are installed as described above, but in parallel with this work, inside the reactor containment vessel 3, equipment 11, piping 12 that supplies cooling water to the inside of the reactor and the control rod pressure mechanism, etc. are installed one after another, connections with the reactor pressure vessel 5 are also made, and the installation within the reactor containment vessel 3 is completed.

However, in the conventional method of installing a reactor pressure vessel, these parts are disassembled and transported to the construction site in multiple shipments, making transportation extremely complicated. Accurate positioning and centering of parts is difficult, and special equipment is required for positioning and centering work, and these operations are affected by weather, dust, outside temperature, atmosphere, etc., so for example, welding For quality control purposes, it is necessary to weld only when the welds are in good condition, which increases the construction period.Also, since the work is outdoors, a large protective sheet is placed above the containment vessel to protect it from wind, snow, and rain. Furthermore, after the parts that will become the reactor pressure vessel are brought in, work on the reactor building construction site and inside the reactor containment vessel must be carried out simultaneously. Since this process has to be carried out, there is a risk that problems may arise with the safety and quality of the completed reactor pressure vessel.

In this way, the conventional method of assembling a large number of parts at the power plant construction site, rather than assembling the reactor pressure vessel at a manufacturing factory and transporting it, requires a significantly long time to install the internal structure of the pressure vessel, and it takes a long time to install the entire nuclear power plant. This became a critical path during the construction period, and was the biggest reason why the entire construction process took a long time.

The present invention was devised to solve the various inconveniences mentioned above, and involves manufacturing and assembling a nuclear reactor pressure vessel in a manufacturing factory, further configuring transportation and curing means for the reactor pressure vessel, and then By transporting the reactor pressure vessel, transportation is realized and made safer, while the assembly work of the reactor pressure vessel at the power plant construction site is eliminated, and the transported reactor pressure vessel is immediately installed using a mobile crane. All you have to do is do the work, and the construction period can be significantly shortened.
The present invention also provides a method for installing a reactor pressure vessel that can improve the safety of the reactor pressure vessel assembly work and ensure quality.

As in the present invention, the reactor pressure vessel, internal structure, and control rod housing are manufactured in advance at a manufacturing factory,
It has never been done in the past to transport nuclear power plants by sea or other means to the construction site of a nuclear power plant and install them in a containment vessel.

This is because in a boiling water reactor, the total weight of the reactor pressure vessel, internal structures, and control rod housing is over 1,000 tons, so the stress concentration that occurs in each component during transportation is This is because it is considered large. Furthermore, since nuclear reactors are a technical field that requires an extremely high level of safety, it is necessary to verify the safety of construction methods in advance. In the past, such new construction methods were not considered at all, and traditional assembly methods were used at the construction site.

In view of the uniqueness of the field of nuclear reactor technology, the present invention has been developed to manufacture reactor pressure vessels, internal structures, and control rod housings in advance in a manufacturing factory, and to provide sufficient strength to transport them to the construction site of a nuclear power plant. This was proposed after overcoming the above requirements and further verifying the safety of each component through actual transportation.

The construction method of the present invention, devised based on such technical requirements, will be described below as shown in Figures 4 and 5, which show the configuration of nuclear reactor equipment in which the reactor pressure vessel of the present invention is installed.
This will be explained with reference to the figures.

FIG. 4 is a longitudinal sectional front view showing the installed state of the reactor pressure vessel housed in the reactor building. The reactor building 1 has a containment chamber 3 defined by a containment wall 2 in the center, and inside the containment chamber 3 there is a pressure vessel installation foundation 4 and a reactor pressure vessel 5 installed on the foundation 4. It is constructed with a cylindrical biological shielding wall 6 for surrounding the body. This reactor building 1 is constructed before the reactor pressure vessel 5 is manufactured at a manufacturing factory and transported. Reactor pressure vessel 5
is mounted on a horizontal rail 7 so that the containment room 3 is directly below, and is lifted into the containment room 3 by a mobile crane 9 that can move horizontally using a roof truss 8 built inside the reactor building 1 as a guide. It is housed so as to be lowered from above and installed on the pressure vessel installation base 4. The pressure vessel installation base 4 and the biological shielding wall 6 are supported by the containment wall 2 via the containment chamber internal structure 10, and the reactor pressure vessel 5 is installed outside the biological shielding wall 6 in the containment chamber 3. The necessary equipment 11 for controlling is the internal structure 10 of the containment chamber.
The piping 12 that supplies cooling water etc. to the reactor pressure vessel 5 is installed inside the building and penetrates the containment wall 2 and further penetrates the biological barrier wall 6 to supply cooling water etc. to the reactor pressure vessel 5. Connected to required locations.

Figure 5 shows the reactor pressure vessel 5 in a transportable state.
FIG. The reactor pressure vessel 5 includes a pressure vessel main body 5A, a jet pump 5B which is an internal structure of the pressure vessel, a shroud 5C, and a core support plate 5.
D, upper grid plate 5E, LPCI coupling ring 5F,
In-core housing 5H, guide rod 5J, core spray line 5K, and water supply spargeer 5L
, control rod housing 5G and drain line 5
It is formed by welding and assembling the parts I and I.

The reactor pressure vessel 5 is manufactured and assembled in a manufacturing factory, and is transported in a collapsed state due to transport height restrictions of transport vehicles. Control rod housing 5G
protrudes from the bottom of the pressure vessel main body 5A, and there is a risk of damage due to an unexpected accident during transportation.
It is covered by a transport curing skirt 13 installed on the lower seat 5M of the pressure vessel main body 5A.
Further, the reactor pressure vessel 5 is placed on a transport skid 16 which forms a set via a support structure 14 attached to the skirt 13 and a support structure 15 attached to one side of the head of the pressure vessel body 5A.

Next, the reactor pressure vessel installation method of the present invention will be explained using an embodiment of the above-mentioned configuration.

First, in the manufacturing factory, the pressure vessel main body 5A, the jet pump 5B, which is the pressure internal structure, the shroud 5C, and the core support plate 5 are manufactured by each manufacturing machine.
D, upper grid plate 5E, LPCI coupling ring 5F,
In-core housing 5H, guide rod 5J, core spray line 5K, and water supply spargeer 5L
and control rod housing 5G, drain line 5
The reactor pressure vessel 5, which is a completed product, is manufactured by welding and assembling these parts in the required order.

Next, the skirt 13 is attached to the lower seat part 5M of the pressure vessel main body 5A so as to cover the control rod housing 5G protruding from the lower seat part 5M of the pressure vessel main body 5A,
Further, a support structure 14 is fixed to this skirt 13, and a support structure 15 is also attached to one side of the head of the pressure vessel main body 5A, and then the reactor pressure vessel 5 is fixed to the pair of support structures 14 and 15. Then, place it on a pair of transportation skids 16, 16 and fix it. The transport skid 16 may be one having rollers or one having many round steel pipes lined up to form a roller.
6 and 16, it becomes movable. Then, the reactor pressure vessel 5 is lowered using a winch (not shown), etc., moved to the required position, loaded onto a transport vehicle (or ship) using a crane, and transported from the manufacturing plant to the nuclear power plant construction site. transport.

On the other hand, at the nuclear power plant construction site, the reactor building 1 is constructed in parallel with the above-mentioned factory fabrication of the reactor pressure vessel 5. The reactor building 1 is constructed before the reactor pressure vessel 5 is transported, and has a base 4 for installing the pressure vessel and a cylindrical living body to surround the reactor pressure vessel 5 in the center. Shielding wall 6
etc., in the containment chamber 3, and piping 12 for supplying cooling water to the reactor pressure vessel 5 is all installed except for the connection part with the reactor pressure vessel 5, and other supports and PIPEWHIP-STRUCTURE and various equipment will also be installed. The inner ends of the pipes, etc. that protrude inward from the biological shielding wall 6 are located outside the outer diameter of the reactor pressure vessel 5, thereby making it possible to suspend the reactor pressure vessel 5. . Note that the pipe whip structure is a part of the internal structure 10 of the containment chamber, and is used to protect other healthy pipes, equipment, etc. from the whiplash phenomenon of the pipes in the unlikely event that the pipes break.

Next, the reactor pressure vessel 5 that has been transported to the construction site is unloaded from the transport vehicle using a crane at a position as close to the reactor building 1 as possible. The mobile crane 9 installed at
4, 15 and the skirt 13 from the reactor pressure vessel 5, and then hoisted to the required height by a mobile crane, moved horizontally, and when they reach just below the containment room 3, are lowered and placed inside the containment room 3. The lower seat part 5M is placed on the installation base 4 and is seated, centered and fixed at an appropriate position. After that, the reactor pressure vessel 5 is connected to the piping 12 and other auxiliary equipment, and finally the remaining work on the upper part of the reactor building 1 is completed, which completes the installation work of the reactor pressure vessel 5 and the construction of the reactor building 1. complete.

As described above, the reactor pressure vessel installation method of the present invention involves dividing the reactor pressure vessel and the reactor containment vessel, manufacturing them separately, and inserting the factory-produced nuclear reactor into the reactor containment vessel that is ready to receive the reactor pressure vessel. Since the reactor pressure vessel is transported and installed, the following effects are achieved.

(1) Since the reactor pressure vessel and the reactor containment vessel can be manufactured independently, there is no interference between the manufacturing processes of both, and the construction period can be shortened. Moreover, each production can be carried out in a wide working space, making the work safe and quick.

(2) Compared to the conventional method of assembling the reactor pressure vessel at the construction site of a nuclear power plant, it is easier to store the reactor, such as a changing room for keeping it clean and a special chute to carry the control rod housing into the lower part of the pressure vessel body. It does not need to be provided inside the vessel, and does not require special equipment for centering the shroud or reactor pressure vessel or precise work for centering.

(3) Because the reactor pressure vessel is manufactured at the manufacturing factory,
For example, quality control of welded parts etc. is not affected by weather, outside temperature, etc., so the construction period is significantly shortened and the quality is further improved.

In addition, in the reactor pressure vessel installation method of the present invention, the reactor pressure vessel, in which the control rod housing is covered with a skirt, is transported on a transportation skid via a support structure, so that the reactor pressure vessel as a completed product is transported. It can be manufactured at a manufacturing factory and safely transported to the nuclear power plant construction site.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing the reactor pressure vessel and its internal structures, Figure 2 is a sectional view of the reactor containment vessel section showing a conventional reactor pressure vessel installation method, and Figure 3 is a sectional view of the conventional reactor pressure vessel. Figure 4 is a cross-sectional view similar to Figure 2 showing the installed state of the internal structure of the reactor pressure vessel, and Figure 4 shows the installed state of the reactor pressure vessel accommodated in the reactor building, according to an embodiment of the reactor pressure vessel installation method of the present invention. FIG. 5 is an explanatory front view of the structure and transportable state of the reactor pressure vessel. 1...Reactor building, 4...Pressure vessel installation foundation,
5... Reactor pressure vessel, 6... Biological shielding wall, 9... Mobile crane, 13... Skirt, 14, 15... Support structure, 16... Transport skid, 5A... Pressure vessel body, 5C... Shroud, 5G... Control rod housing .

Claims (1)

[Claims] 1 The pressure vessel body of the reactor pressure vessel is manufactured in advance at a manufacturing factory, and at least a shroud is provided within the pressure vessel body, and the control rod housing is attached to the shroud so as to protrude from the lower seat of the pressure vessel body. The control rod housing protruding from the lower seat of the pressure vessel body is covered with a skirt and a first support structure attached to the skirt, and the head of the pressure vessel body is then covered with a skirt and a first support structure attached to the skirt. The reactor pressure vessel is laid down and placed on a pair of transport skids to transport the land portion from the fabrication plant to the construction site via a second support structure attached to the reactor pressure vessel. By the time of transportation, the reactor pressure vessel installation foundation, the biological shielding wall that accommodates the reactor pressure vessel, and attached equipment such as piping, supports, and pipe whip structures connected to the reactor pressure vessel The reactor pressure vessel is constructed in advance so that it can be lifted and lowered, and the transported reactor pressure vessel is lifted by a crane and the transportation skid, the first and second support structures, and the skirt are assembled. Remove the reactor pressure vessel and seat it on the base for installing the reactor pressure vessel, and then connect the piping and supports and the connection points to the reactor pressure vessel such as the pipe whip structure with the reactor pressure vessel. A nuclear reactor pressure vessel installation method characterized by comprising: