JPS6227694A - Method and device for inspecting pressure withstanding of piping for high-pressure casing - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to pressure testing technology for high-pressure piping that is directly or indirectly connected to a high-pressure casing for a steam turbine of a nuclear power plant. The present invention relates to a method and an apparatus for performing a pressure test by applying internal pressure to the welded joints of the high-pressure pipes after the assembly of each component of a turbine plant is completed.

[Background of the invention]

The piping technology involved in the installation of a steam turbine.

For example, ``Method for installing main turbine in large-scale power generation equipment'' described in Japanese Patent Application Laid-Open No. 56-29003 is known.

The above invention was made in order to solve the technical difficulties caused by the distortion of the casing associated with the installation of a large turbine.
It has many excellent practical effects for this purpose.

However, the steam turbine prime mover for nuclear power generation is dependent on the steam conditions unique to nuclear power generation.

There are also difficult problems that are not addressed by the above-mentioned known inventions.

One of the problems with nuclear power generation is that the flow rate of steam is larger than in thermal power generation, and the steam is wet.

That is, a moisture separator is installed and the high pressure turbine casing (
The problem is that high-pressure piping must be installed between the high-pressure casing (abbreviated as high-pressure casing) and the moisture separator and valves, and that the assembly of the component equipment cannot be started until the pressure test of the high-pressure piping is completed. There is.

The fact that assembly of the equipment cannot begin until piping has been connected to the component parts of the equipment and a pressure test has been completed increases the installation period. Therefore, if the assembly of the equipment can be started without the pressure test of the pipe attachment part (that is, if the pressure test of the pipe can be performed after the high-pressure casing is assembled), the construction period can be shortened.

Construction of nuclear power generation facilities requires huge investment and
Once the plant starts operating, it will generate huge profits (profits from the sale of electricity), so the economic gains and losses caused by the length of the construction period are extremely large.

Next, we will discuss in detail technical issues related to piping for steam turbine plants for nuclear power generation, especially high-pressure turbines.

Figure 3 is a steam system diagram of a nuclear power plant. This system diagram shows an example of an I100 MW class nuclear power generation turbine. This example is a non-reheat regenerative condensing tandem compound employing 38-inch blades in the final stage, including a high-pressure turbine 10 and a recirculating exhaust low-pressure turbine 11. It is constructed by providing a steam control valve 3, a moisture separator 61, a combination intermediate valve 7, cross-around pipes 8 and 9°, and main steam pipes 4 and 5.

System-wise, main steam from the nuclear reactor passes through four main steam stop valves 12, and is controlled by four steam control valves 3. The main steam stop valve 12 and the steam control valve 3 are directly connected. The steam is introduced into the high-pressure turbine 10 through the upper half main steam pipe 5 and the lower half main steam pipe 4 that have passed through the steam control valve 3 . The high-pressure turbine 10 is comprised of several double 70-stage expansion stages and is controlled by a normal throttle governing system. The steam expanded in the high-pressure turbine 10 and subjected to work is led to two moisture separators 6 through four cross-around pipes 8. High pressure turbine 1
Due to the expansion at zero temperature, the steam has a humidity of around 10%, but as it passes through the cross-around pipe 8 and the moisture separator 6, the moisture is separated and the humidity becomes around 2%, or 19 degrees. .

after that.

It enters six combined intermediate valves 7 through cross-around pipes 9. This combination intermediate valve 7 is composed of an intermediate steam stop valve and an intercept valve, and serves to suppress the maximum speed increase when the turbine I-IJ turns to below the operating speed of the emergency governor. .

Further, one combination intermediate valve 7 is installed close to the inlet of each low pressure turbine 11 so that the distance to the low pressure turbine 11 is the shortest.

The steam entering the three low-pressure turbines 11 converts thermal energy into torque at a double 70-stage expansion stage formed from around 10 stages, and then is led to a condenser (not shown) through an exhaust port. .

Regarding the above-mentioned turbine installation procedure, a method is generally used in which a base plate for the low-pressure turbine and a base plate for the high-pressure turbine are installed, and then the low-pressure turbine 11 and the high-pressure turbine 10 are assembled on the respective base plates. ing.

Since the combination intermediate valves 7 connected to the low-pressure turbine 11 are each installed on a turbine pedestal, the low-pressure turbine 11
Although no special external force is applied to .

Since external forces from the main steam pipes 4 and 5 and external forces from the cross-around pipe 8 are applied to the high-pressure turbine, assembly and adjustment of the high-pressure turbine 10 is only possible after confirming the eccentricity and displacement after connecting each. I can't do it. Therefore, after temporarily setting the high pressure lower half casing 1 and the high pressure upper half casing 2 in the high pressure turbine 10,
Main steam pipes 4 and 5 to be connected. A cross-around tube 8 is set. Furthermore, the main steam pipes 4 and 5 and the cross-around pipe 8 are usually brought in with a fixed length of 5 m.

It is necessary to connect these pipes together by welding.

In addition, the welded parts of these pipes must undergo a specified pressure test (Nuclear Technical Standards). High pressure casing 1
and 2 can be pressure tested at a factory with careful quality control and delivered to the site, but as mentioned above, the pressure test of the main steam pipes 4, 5 and the cross-around pipe 8 must be carried out on site. Specifically, the main steam pipes 4 and 5 are connected to the high pressure upper half casing 2 and the high pressure lower half casing 1. Furthermore, the on-site welding of each pipe of the cross-around pipe 8 was performed under prescribed heat treatment, and a non-destructive inspection was conducted.
After inspecting the welded parts and confirming that there are no defects, a pressure test is performed on each weld. However, the high pressure upper half casing 2
The high-pressure casing side connection of the main steam pipe 5 is a flange type, so attaching a cover to this flange would be enough, but since the connection with the steam control valve 3 is connected by welding, It will be implemented as shown in Figure 5. FIG. 4 is an explanatory view showing the positions of the connection part AA between the high-pressure lower half casing 1 and the cross-around pipe 8, and the connection part A'8' with the main steam pipe 4.5. FIG. 5 is a sectional view showing the details of the AA section, and the A/A/ section has the same structure as that in FIG. 5.

A temporary pipe 13 is constructed by welding and fixing the end plate 14 in advance. This temporary pipe is a member that becomes part of the cross-around pipe 8 or part of the main steam pipes 4 and 5 through the processing described below.

Reference numeral 16 indicates a position preset by design. After the pressure test, the temporary pipe 13 is cut at this position 16. 17 is
The position to be welded to the high-pressure lower half casing 1 is shown. A pre-configured short pipe (a member having the length of arrow 15 and corresponding to this part) is inserted and welded between the above-mentioned cutting part 16 and welding position 17, and it is confirmed that there are no defects by radiographic inspection. Check. Similarly, the high-pressure lower half casing 1 and the cross-around pipe 8 are also welded to the high-pressure lower half casing 1 in the same manner as the main steam pipes 4 and 5, and subjected to radiation inspection. After completing the above work, the high pressure turbine was assembled and adjusted. With this construction method, the high pressure turbine 2 cannot be assembled or adjusted until the piping work is completed, resulting in waiting time for each work.In this example, the entire construction period required 17 months, as shown in Figure 6. was.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a pressure resistance test method and a pressure resistance test device that can perform a pressure test of high pressure piping in parallel with the assembly and adjustment work of a high pressure casing or after the assembly work. It is something to do.

[Summary of the invention]

In order to achieve the above object, the inspection method of the present invention is a method of pressure testing main steam piping and cross-around pipes connected to a high-pressure turbine casing for nuclear power generation. Perform a pressure resistance test of the main steam piping independently with the connection made by
In addition, the present invention is characterized in that the pressure resistance test of the cross-around pipe is performed independently with the high-pressure casing and the moisture separator, and the moisture separator and the combined intermediate valve connected to each other by the cross-around pipe.

[Embodiments of the invention]

FIG. 1 is an explanatory diagram of the inspection method of the present invention. After setting the high pressure lower half casing 1 as shown in Fig. 1, the main steam pipe 4
and 5. Furthermore, while setting the steam control valve 3 and assembling the high-pressure upper half casing 2, insert the pressure test partition plate 19 into the diaphragm insertion groove 18 in the high-pressure casing, as shown in FIG. , the sealing rubber 20 and the partition plate 19. Adjustment porto 211 bag nut 2
2. Assemble the partition plate reinforcing material 23 and prepare for the pressure test, and while temporarily welding the main steam pipes 4 and 5 to each other, carefully perform predetermined heat treatment and welding. Further, the steam control valve 3 is provided with a sealing cover 24, as shown in FIG. Cover 25. Seal rubber 27 and bolts 268 are used to partition the inside of steam control valve 3 so that internal pressure can be applied to welded portion W of main steam pipe 4.5, and a pressure resistance test is performed at a specified pressure. After completing the pressure test of the main steam pipe line in this way, the steam control valve 3. High pressure lower half casing 1. Partition plate 19 for pressure resistance test inside high pressure upper half casing 2
, 25, 27, etc. and cleaned them, as shown in Figure 12, which is an enlarged view of section D in Figure 11, the diamond slam insertion part 2.
The partition plate 29 is inserted into the backing head insertion part 30, and the partition plate 3 is inserted into the backing head insertion part 30 as shown in FIG.
1.

Further, as shown in FIG. 11, a cover 34 is attached to the end face of the high-pressure casing, and a partition plate adjustment bolt 32 and an adjustment washer 33. Holder bolt 35. Prepare for the pressure test using sealing rubber 36, etc. In parallel with this preparatory work, the cross-around pipes 8 and 9h, the moisture separator 6, and the combination intermediate valve 7 are assembled in the high-pressure lower half casing 1 (FIG. 2). As shown in FIG. 14, the combination intermediate valve 7 holds the steam outlet side cover 37 with a bolt 38. Attach with the retaining nuts 39, and then attach the cover 40 with bolts 41. In this way, the inside of the combination intermediate valve 7 is partitioned off so that the entire internal pressure can be obtained at the welded portion W' of the cross-around pipe 9. In this state, a pressure test is performed at a predetermined pressure. If the pressure test is passed, each partition plate (cover) will be removed.

By performing the pressure resistance test as described above, the pressure resistance test of the piping can be performed at the same time as the high pressure casing assembly work.
Further, since the pressure resistance test of the piping can be performed after the assembly and adjustment of the high-pressure casing, the waiting time for piping work and the waiting time for assembling the high-pressure casing can be significantly reduced.

FIG. 6 shows an example of a process chart in the prior art.

In this conventional example, cross-around pipe work (X) and main steam pipe work (M) are carried out from the middle of the second month to the end of April, and after a pressure test (T) is carried out, from the middle of the sixth month to the end of April. As assembly work (IO) for high-pressure steam equipment was being carried out towards the middle of the month, one assembly (E()) was completed at the end of September.

When the present invention is applied to a steam power plant similar to the one described above, the result will be as shown in FIG. In other words, in parallel with the cross-around pipe work (X) and the main steam pipe work (M), assembly and adjustment of the high-pressure steam equipment is performed, and then the pressure test (T) is performed, so the main assembly (I ()) The construction period will be completed by the end of August, reducing the construction period by one month compared to the conventional technology (Figure 6).

Considering that the investment amount for a nuclear power plant is huge and the interest burden is high, the economic effect of shortening the construction period by one month is significant.

〔Effect of the invention〕

As detailed above, according to the voltage resistance testing method of the present invention,
Since it is possible to perform a pressure test of high-pressure piping without being tied to the schedule for assembling and adjusting high-pressure casings, it greatly contributes to shortening the construction period. Furthermore, according to the pressure resistance testing device of the present invention, the above method can be easily carried out and its effects can be fully exhibited.

[Brief explanation of the drawing]

1 to 3 are schematic steam piping diagrams for explaining one embodiment of the method of the present invention. FIG. 4 is an explanatory diagram of piping for a steam engine, and FIG. 5 is an enlarged sectional view of section AA in FIG. 4. FIG. 6 is a chart showing an example of a nuclear turbine installation work schedule according to the prior art, and FIG. 7 is a chart showing an example of a nuclear turbine installation work schedule according to an embodiment of the present invention. FIG. 8 is an explanatory diagram of one embodiment of the device of the present invention, and FIG.
It is an enlarged detailed view of part B in the figure. 10 and 11 are explanatory diagrams of embodiments different from the above, respectively, FIG. 12 is an enlarged detailed view of the D section of FIG. 11, and FIG.
The figure is also an enlarged detailed view of part C. FIG. 14 is an explanatory diagram of an embodiment further different from the above. 1... High pressure lower half casing, 2... High pressure upper half casing, 3... Steam control valve, 4.5... Main steam pipe, 6
... Moisture separator, 7... Combination intermediate valve, 8.9...
・Cross-around pipe, 10...High pressure turbine, 11
...Low pressure turbine, 12...Main steam stop valve, 13.
...Temporary pipe, 14...End plate, 15...Short pipe, 16
...Pipe cutting section. 17... Welded part with high pressure casing, 18... Diaphragm insertion groove, 19... Partition plate for pressure test, 20...
... Seal rubber, 21 ... Adjustment bolt, 22 ...
- Cap nut, 23... Reinforcing material for partition plate, 24... Seal cover, 25... Cover, 26... Bolt,
27... Divider plate for pressure resistance test, 28... Diaphragm insertion part, 29... Partition plate for pressure resistance test, 30... Backing head insertion part, 31... Partition plate, 32... Partition plate Adjustment bolt, 33...adjustment washer, 34.
... Cover, 35 ... Holding bolt, 36 ... Seal rubber, 37 ... Cover, 38 ... Holding bolt,
39... Presser nut, 40... Cover, 41...
·bolt.

Claims (1)

[Claims] 1. A method for performing a pressure resistance test of a main steam pipe and a cross-around pipe connected to a high-pressure turbine casing for nuclear power generation, in which the high-pressure casing and a steam control valve are connected by the main steam pipe. At the same time, the pressure resistance of the cross-around pipes was inspected with the high-pressure casing and the moisture separator, and the moisture separator and the combined intermediate valve connected by cross-around pipes. A pressure resistance test method for high-pressure casing piping, which is characterized by performing the test independently. 2. For each of the main steam piping and cross-around pipes connected to the high-pressure turbine casing for nuclear power generation, inside the equipment to be welded to these piping,
A pressure resistance inspection device for high-pressure casing piping, characterized in that a removable partition plate is provided to apply internal pressure to the welded connection points.