JPH0252238B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an assembly method for assembling a safety vessel and a reactor vessel for a tank-type fast breeder reactor in a factory, thereby significantly reducing the on-site assembly work process. It is.

[Background of the Invention] FIG. 5 shows a longitudinal section of the reactor structure of a tank-type fast breeder reactor. In the structure of this reactor body, a reactor vessel 1 and a safety vessel 2 are fixed to a roof slab 3 by welding to form a sealed space. Inside the reactor vessel 1 , a reactor core 4 is supported by a reactor support structure 10 . On the other hand, roof slab 3 has
A main cooling heat exchanger 6 that exchanges heat between high-temperature primary sodium and secondary sodium heated by the reactor core 4, a main circulation pump 7 that circulates the primary sodium within the reactor, and control rods that control the output of the reactor core 4. It has a structure in which equipment such as a core upper mechanism 8 that includes a drive mechanism (not shown) and a rotary plug 9 that positions a fuel exchanger (not shown) at a predetermined position during fuel exchange are mounted.

The on-site assembly method of this nuclear reactor will be explained with reference to FIG. Among the parts sent separately to the site, first, the safety container 2 is temporarily placed on a plurality of A jacks 12 attached to the reactor cavity 11. Next, the reactor vessel 1 is placed on the R jacks 14, which are also installed in plural numbers on the base surface of the reactor cavity 11, passing through the temporary opening 13 provided at the bottom of the safety vessel 2. Hang it from above and place it temporarily. Thereafter, the roof slab 3 is installed on the reactor cavity 11, the reactor vessel 1 is lifted with the R jack 14 to adjust its direction, and is welded to the roof slab 3 to be integrated. Next, the safety container 2 placed on the A jack 12
After jacking up and adjusting the direction, connect it to roof slab 3 by welding. As a result, reactor vessel 1,
The safety container 2 and the roof slab 3 are integrated. Based on this state, the core 4, main cooling heat exchanger 6, main circulation pump 7, rotary plug 9, and core upper mechanism 8 are assembled one after another, and the assembly is almost completed.

Here, the safety vessel 2 is a stainless steel container with a diameter of about 20 m or more and weighs several hundred tons, and the reactor vessel is also made of stainless steel and is an extremely large container with a diameter of about 20 m and a weight of several hundred tons. The assembly work is extremely difficult. The work of attaching these two containers to the roof slab 3 requires a long period of time even during the reactor structure assembly period and constitutes a so-called critical path, so it is desired to shorten this time. Further, in this conventional example, due to the temporary placement relationship between the safety vessel 2 and the reactor vessel 1, it is necessary to provide a temporary opening 13 at the bottom of the safety vessel 2 for temporary placement of the reactor vessel 1. This temporary opening 13 is closed by welding after the reactor vessel 1 and safety vessel 2 are each attached to the roof slab 3 and the A jack 12 and R jack 14 are removed. The integrity of this part must be confirmed using ultrasonic flaw detection, etc. Furthermore, adjusting the orientation when assembling the reactor vessel 1 and the safety vessel 2 to the roof slab 3 is a very difficult task because each vessel weighs several hundred tons.

Next, for on-site reactor assembly work, there is a method that does not provide a temporary opening in the safety vessel 2 for temporary placement of the reactor vessel 1. Although it is conceivable to take out the spacer after welding it to the roof slab 3, there are problems in how to remove and recover the spacer and that it is technically difficult to adjust the direction.

Furthermore, there is a proposal to assemble the reactor vessel, etc., by injecting liquid into the space of the reactor vessel and utilizing the buoyancy of the liquid, thereby eliminating the need for jacking.
56-27698). However, with this plan, the predetermined distance cannot be maintained unless some method is used to resist buoyancy and prevent the reactor vessel from rising too far above the safety vessel. Moreover, high stress occurs when assembling the reactor internals, and work while floating in water is unstable, so the amount of work on site does not decrease much, and it is necessary to shorten the period as a critical path. The problem is not improved.

[Purpose of the invention]

An object of the present invention is to provide a method for assembling a safety vessel and a reactor vessel, which greatly reduces the on-site assembly process of super-large canned products that become the safety vessel and reactor vessel of a tank-type fast breeder reactor.

[Summary of the invention]

In order to achieve the above object, the present invention positions and fixes a nuclear reactor vessel in a face down state on at least a part of a roof slab, then covers the safety vessel from above, positions it, fixes it to the roof slab, and integrates it. We propose a method of transporting the safety vessel and reactor vessel as they are to the reactor construction site, and then erecting them on-site and installing them in the designated position.

[Embodiments of the invention]

Next, an embodiment of the present invention will be described with reference to FIGS. 1 to 4. Figure 1 is a diagram showing a safety vessel manufactured while lying face down on a surface plate, Figure 2 is a diagram showing a reactor vessel manufactured in a state lying face down on a surface plate and part of the roof slab, FIG. 3 is a cross-sectional view of FIG. 2, and FIG. 4 is a diagram showing how the safety vessel and reactor vessel assembled together according to the present invention are installed at the reactor construction site.

Now, in FIG. 1, 22 is a surface plate. The safety container 2 is fabricated in a face down state on this surface plate 22 in a factory by sequentially welding steel plates from the bottom (the top when turned over). As will be described later, the manufactured safety vessel 2 has sufficient strength for assembly to the roof slab and transportation and installation of the assembled reactor vessel 1, safety vessel 2, and roof slab 3 as one body. Install trunnion 20. after that,
The appearance and dimensions are inspected, and the integrity of the welded portion is confirmed by nondestructive testing such as ultrasonic flaw detection, and the safety container 2 is completed.

On the other hand, as shown in FIG. 2, the reactor vessel 1 is constructed by sequentially welding steel plates from the bottom onto at least a portion of the roof slab 3 placed upside down on another surface plate 22 in the factory. It is manufactured upside down. Furthermore, a trunnion 21 having sufficient strength is attached to the roof slab to suspend the roof slab, the reactor vessel 1, and the safety vessel 2 together into the reactor cavity 11, as will be described later.

The reason for mentioning at least a part of the roof slab 3 here is that if the strength is sufficient for the lifting work, and if it is convenient for the subsequent equipment assembly work, it is better not to assemble the entire roof slab at that stage. Because it's good.

Therefore, the important points of this example are (1) that a roof slab that has sufficient strength for the lifting work is assembled, and (2) that the base 5, which rests on the vessel setting foundation at the reactor construction site, is installed. (3) The steel plate forming the upper end portion of the safety container 2 is attached to the roof slab 3 at the factory stage.

Note that the reason why only the steel plate that forms the upper end of the safety container 2 was assembled to the roof slab 3 first, separate from the majority of the safety container, was in consideration of workability and accuracy issues. If there are no problems in these respects, the safety container may be integrally completed up to the upper end and assembled to the roof slab as described below.

After that, the appearance and dimensions of the reactor vessel 1, the upper end of the safety vessel, and the roof slab 3 are inspected, and the soundness of the welded parts is confirmed by non-destructive testing such as ultrasonic testing, and the safety of the reactor vessel 1 and safety vessel is confirmed. The assembly of the upper end portion of the container and at least a portion of the roof slab 3 is completed.

Next, the safety vessel 2, which has been completed separately, is suspended by a lifting machine, etc., and moved to the top of the reactor vessel 1.
Cover this. Then, it is gently lowered onto the upper end of the safety container 2 that has been attached to the roof slab 3 in advance, and fine adjustments such as directionality and centering are made, and after preliminary welding, final welding is performed. Attach safety container 2 as shown. After that, the appearance and dimensions are inspected, and the soundness of the welded parts is confirmed by non-destructive testing such as ultrasonic testing.
An integrated product with at least a part of is completed in a factory.

The entire container completed at the factory is transported face down to the site.

The on-site installation process is significantly shortened, unlike the conventional example shown in FIG. In other words, at the site, the container, which was sent face down, is erected using a lifting machine, moved to the upper part of the reactor cavity 11, and lowered onto the foundation for setting the container, as shown in Figure 4. vinegar. After adjusting and confirming the position, simply fix the base 5 to the foundation with bolts (not shown).
Installation is complete.

As described above, according to this embodiment, the on-site assembly process for super-large canned products that become the safety vessel and reactor vessel of a tank-type fast breeder reactor can be significantly reduced. Particularly when all the roof slabs are assembled in the factory, assembly at the reactor construction site is virtually unnecessary.

〔Effect of the invention〕

According to the present invention, the following effects can be obtained.

(1) The on-site installation process is significantly reduced.

(2) The quality of safety containers will improve.

(a) Multiple temporary openings for temporary reactor vessel reception are no longer required, reducing the number of welded parts and eliminating the need for non-destructive testing such as ultrasonic testing.

(b) On-site welding of the parts to be assembled to the roof slab is eliminated, and the work can be done reliably at the factory, eliminating the need for on-site non-destructive testing such as ultrasonic testing.

(3) Reactor vessels will be of higher quality. Welding work can be carried out in a good environment within the factory, and there is no need for on-site welding of the parts to be assembled to the roof slab, which eliminates the need for on-site non-destructive testing such as ultrasonic flaw detection.

(4) The efficiency of assembly work between the safety vessel and the reactor vessel is improved.

(a) Since the containers are assembled face down, centering between the containers can be done safely and easily under stable working conditions.

(b) Workability is good because the welding work for the assembly to the roof slab is done at the factory.

(5) It also has economic effects.

(a) Labor costs can be reduced by shortening the on-site installation process.

(b) Transportation costs are reduced because the safety container and reactor container are transported as one unit.

[Brief explanation of drawings]

Figure 1 is a diagram showing a safety vessel manufactured while lying face down on a surface plate, Figure 2 is a diagram showing a reactor vessel manufactured in a state lying face down on a surface plate and part of the roof slab, FIG. 3 is a cross-sectional view of FIG. 2; FIG. 4 is a diagram showing how the safety vessel and reactor vessel assembled together according to the present invention are installed at the reactor construction site;
FIG. 5 is a diagram showing a longitudinal section of the reactor structure of a tank-type fast breeder reactor, and FIG. 6 is a diagram showing a conventional method of assembling the safety vessel and reactor vessel at a reactor construction site. DESCRIPTION OF SYMBOLS 1...Reactor vessel, 2...Safety vessel, 3...Roof slab, 4...Reactor core, 5...Base, 6...Main cooling heat exchanger, 7...Main circulation pump, 8...Core upper mechanism, 9...
Rotating plug, 10... Reactor support structure, 11... Reactor cavity, 12... A jack, 13... Temporary opening, 14... R jack, 20, 21... Trunnion, 22... Surface plate.

Claims (1)

[Claims] 1. A method for assembling a safety vessel and a reactor vessel that are fixed together to a roof slab of a tank-type fast breeder reactor, including a step of positioning and fixing the reactor vessel in a face down state on at least a part of the roof slab. and,
There are two steps: placing the safety container on top of the reactor, positioning it, and fixing it to the roof slab; transporting the integrated safety container and reactor vessel as they are to the reactor construction site; and rebuilding the reactor at the site. 1. A method for assembling a safety vessel and a reactor vessel, comprising the steps of installing. 2 In claim 1, the step of fixing the safety container to the roof slab includes the step of fixing the upper end of the safety container at a predetermined position on the roof slab outside the reactor vessel, and the step of fixing the safety container to the roof slab. A method for assembling a safety vessel and a reactor vessel, comprising the step of placing the remaining part of the safety vessel to form the entire safety vessel.