JP2011047287A - Steam turbine for nuclear power plant and replacing construction method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten a work period by shortening a process and shorten an occupying time of a hoisting facility such as an overhead crane, in installation-replacement work of a steam turbine for a nuclear power plant, thereby reducing influence on other works and improving a plant operation rate. <P>SOLUTION: An existing steam turbine 1 is carried out of an installation position still in an integrally assembling state, and a continuously newly manufactured steam turbine is carried in and installed still in an integrally assembling state, and the steam turbine is replaced thereby. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a steam turbine installed in a nuclear power plant, and a method for replacing a steam turbine for a nuclear power plant in which an existing steam turbine in the nuclear power plant is replaced with a new steam turbine.

  In a large boiling water nuclear power plant, a steam turbine is installed inside a turbine building, and includes a single high-pressure turbine and a plurality of low-pressure turbines. The equipment constituting such a steam turbine is large and has an assembly weight per passenger compartment exceeding several tens to hundreds of tons, and large related equipment such as turbine auxiliary equipment is located nearby. In addition, large-diameter pipes are also installed.

  With reference to FIGS. 5-7, the arrangement configuration of the conventional steam turbine, turbine building, and steam turbine installed in the same building will be described.

  FIG. 5 is a plan view showing the turbine building and the steam turbine installed in the building. As shown in FIG. 5, one high-pressure turbine 102 is installed on one side of the turbine building 101. For example, three low-pressure turbines 103 are connected in series via a shaft 106 to the high-pressure turbine 102. Yes. A generator 104 is connected to the low-pressure turbine 103 via a shaft 107 via a horizontal shaft 106.

  FIG. 6 is a schematic longitudinal sectional view showing a state in which the turbine building 101 shown in FIG. 5 is cut along the line AA in FIG.

  As shown in FIG. 6, the high-pressure turbine 102, the low-pressure turbine 103, and the generator 104 are installed on the second floor in the turbine building 101 at substantially the same height.

  FIG. 7 is a schematic cross-sectional view showing a state in which the turbine building 101 shown in FIG. 6 is cut along the line BB in FIG.

  As shown in FIG. 7, a condenser 105 is installed in the lower part of the turbine building 101, and a low-pressure turbine 103 is installed above the condenser 105. A working overhead crane 108 is installed on the upper part of the turbine building 101.

  Dry steam is supplied to the high-pressure turbine 102, but the steam supplied to the low-pressure turbine 103 is steam with high wetness. For this reason, in the long-term operation of the power generation facility, a lot of equipment replacement work occurs as a countermeasure against aging deterioration due to wet steam, and further, it is necessary to increase the capacity of the power generation facility. As described above, the low-pressure turbine 103 also corresponds to a large-sized heavy equipment that requires the removal of an aged equipment or a replacement for increasing the capacity.

  In order to replace the low-pressure turbine 103, it is necessary to precede the carry-out of the existing low-pressure turbine 103 which is a large-sized device / heavy object and is composed of a large number of parts. In this case, since existing equipment parts are contaminated with radioactive materials, protective curing is required when carrying out of the radiation control area, and large items such as vehicle compartments and rotors are not suitable for carrying out large items. Dedicated cask is required.

  Moreover, in order to divide and reduce each component of the existing low-pressure turbine 103 and carry it out, it is necessary to dismantle at the installation site. As a means of shortening the construction period of dismantling work, when removing and carrying out an existing low-pressure turbine and installing a newly manufactured low-pressure turbine as a parallel work, a large number of parts will be mixed in the same area. It also takes effort to manage.

  As a conventional concrete turbine replacement method, the following steps (1) to (6) are mainly used. (1) Disassembly of the upper half of the outer casing, (2) Disassembly of the upper half of the inner casing, (3) Disassembly of the upper half nozzle, (4) Disassembly by lifting the rotor, (5) Disassembly of the lower half nozzle, (6) sequential decomposition by lifting the lower half of the internal casing, and replacement of the turbine after decomposition.

Japanese Patent Laid-Open No. 2001-3709

  Conventionally, when replacing a steam turbine for a nuclear power plant, as shown in the above-described steps (1) to (6), the upper half of the outer compartment and the upper half of the inner compartment are disassembled. The upper half nozzle is disassembled, the rotor is disassembled by lifting, the lower half nozzle is disassembled, and the lower half of the internal compartment is lifted.

  As described above, since six types of work have been sequentially performed in the past, when a low-pressure turbine is newly manufactured and replaced, a large amount of work is required and a long time is required for the work. ing. In addition, an economic burden is imposed, and it is a major issue that the facility operation rate decreases due to the plant stoppage during the construction period.

  Furthermore, since a high-speed rotating body is driven in a steam turbine, centering and adjustment work are important, and replacement requires much work.

  The present invention has been made in view of such circumstances, and in the steam turbine replacement work, the work period can be shortened by shortening the process, and at the same time, the occupation time of the lifting equipment such as an overhead crane. It is an object of the present invention to provide a steam turbine for a nuclear power plant and a method for replacing the same, which can reduce the impact on other constructions and improve the plant operating rate.

  In order to achieve the above object, the steam turbine according to the present invention includes (1) an upper half outer casing unit, and (2) a preassembled inner casing, an upper half nozzle, a rotor, and a lower half nozzle. An internal casing side unit is provided, and a steam turbine configured by assembling these two units is provided.

  In addition, in most cases, paying attention to the critical path between unloading the existing steam turbine and the centering adjustment process of the new steam turbine, the present invention uses the existing steam turbine to replace the new steam turbine. Carrying out the installation position in the integrated assembly state, and then carrying in and installing the newly manufactured steam turbine in the integrated assembly state enables the replacement of the steam turbine and the replacement work in a short period of time. Provide replacement method.

  In the present invention, the internal casing (the upper half) on the low pressure side of the steam turbine is disassembled and the rotor and nozzles assembled in the internal casing are assembled at different locations, and the rotor and nozzles are assembled. There is provided a method for replacing a steam turbine for a nuclear power plant, which is subsequently carried into the steam turbine, and the rotor and nozzle are installed as an integrated structure.

  Further, in the present invention, a place different from the installation place of the steam turbine is set as the installation place, the assembly work is performed at the assembly place having a solid floor for the assembly work, and the assembly work at the installation place can be omitted. A replacement method for a steam turbine for a nuclear power plant is provided.

  Further, the present invention provides a replacement method for a steam turbine for a nuclear power plant that is assembled at a place different from the place where the steam turbine is installed, and receives a public inspection at the place.

  Furthermore, the present invention provides a method for replacing a steam turbine for a nuclear power plant characterized in that, when replacing a steam turbine, the device that is the replacement range of an existing steam turbine is removed and carried out while being assembled.

  According to the present invention, in the steam turbine replacement work, the work period can be shortened by shortening the process, and at the same time, the occupation time of the lifting equipment such as an overhead crane can be shortened. The plant operation rate can be improved while reducing the impact on the plant.

The disassembled perspective view of the steam turbine applied in 1st, 2nd and 3rd embodiment of this invention. The longitudinal cross-sectional view of the steam turbine shown in FIG. The cross-sectional view which shows the example of arrangement | positioning of the steam turbine by 2nd, 3rd and 4th embodiment of this invention. The cross-sectional view which shows the turbine building by 4th Embodiment of this invention. The building top view for demonstrating a prior art example. AA line sectional view of Drawing 5. The BB line expanded sectional view of FIG.

  Hereinafter, an embodiment of a steam turbine for a nuclear power plant and a replacement method thereof according to the present invention will be described with reference to FIGS.

First Embodiment (FIGS. 1 and 2)
FIG. 1 is an exploded perspective view showing components of the steam turbine according to the first embodiment of the present invention, and FIG. 2 is a perspective view showing a state in which the components are assembled.

  As shown in FIGS. 1 and 2, the steam turbine to be applied is a low-pressure turbine 1 in this embodiment. The low-pressure turbine 1 has a lower half outer casing 2 whose upper surface is open. On the lower half outer casing 2, a lower half inner casing rotor 3 and blades 4 are provided.

  A lower half nozzle 5 and an upper half nozzle 6 are provided around the blade 4, and a half-cylindrical internal casing 7 having an open bottom surface is provided above the upper half nozzle 6. The internal casing 7 is configured to cover the lower half inner casing rotor 3 and the blades 4 which are low-pressure rotors. The upper peripheral portion of the inner casing 7 is covered with the low-pressure turbine outer casing 8.

  Thus, in the present embodiment, the upper half external compartment unit 9 in which the steam turbine 1 is composed of the external compartment 8, the internal compartment 7 that is assembled in advance, the upper half nozzle 6, the rotor 3, and the lower half nozzle 5. It is the structure provided with the internal compartment side unit 10 which consists of.

  When the low-pressure turbine 1 is assembled, the stationary parts such as the internal casing 7 and the nozzles 5 and 6 and the dynamic part composed of the lower half internal casing rotor 3 and the blades 4 which are low-pressure rotors are centered. Adjust the gap so that the stationary part and the dynamic part do not come into contact with each other, and assemble at an appropriate place other than the installation place in advance.

  The assembled low-pressure turbine 1 is carried into the installation place and joined to the existing low-pressure turbine external casing 8 to complete the new replacement work of the low-pressure turbine 1.

  According to this embodiment, each component such as the low-pressure turbine internal casing 7 and the low-pressure rotor 3 incorporated therein does not need to be assembled at the turbine installation location, but is assembled in advance at an appropriate location other than the installation location. It is possible to provide an easy working method and a steam turbine in which the assembly period is omitted.

  If there is a margin in the height direction of the work place, it is also possible to install the extraction pipe expansion joint connected to the lower part of the internal casing 7 of the low-pressure turbine 1 after installation.

Second Embodiment (FIGS. 1 to 3)
In this embodiment, an existing steam turbine is unloaded from the installation position in an integrally assembled state, and a newly manufactured steam turbine is subsequently loaded and installed in an integrally assembled state to replace the steam turbine. A method for replacing the turbine will be described.

  This embodiment will also be described with reference to FIGS. FIG. 1 is an exploded perspective view showing components of a steam turbine, and FIG. 2 is a perspective view showing a state in which the components are assembled.

  As shown in FIG. 1 and FIG. 2, the steam turbine applied also in this embodiment is a low-pressure turbine 1. The low-pressure turbine 1 has a lower half outer casing 2 whose upper surface is open. On the lower half outer casing 2, a lower half inner casing rotor 3 and blades 4 are provided.

  A lower half nozzle 5 and an upper half nozzle 6 are provided around the blade 4, and a half-cylindrical internal casing 7 having an open bottom surface is provided above the upper half nozzle 6. The internal casing 7 is configured to cover the lower half internal casing rotor 3 and the blades 4. The upper peripheral portion of the inner casing 7 is covered with the low-pressure turbine outer casing 8.

  As described above, in the present embodiment, the steam turbine 1 includes the outer casing 8, the pre-assembled inner casing 7, and the inner casing side unit including the upper half nozzle 6, the rotor 3, and the lower half nozzle 5. It becomes the composition.

  Next, a new replacement operation of the low-pressure turbine 1 will be described with reference to FIG. FIG. 3 is a schematic cross-sectional view showing a state in which the existing external casing 8 is installed in the turbine building 11.

  As shown in FIG. 3, a condenser 12 is installed in the lower part of the turbine building 11, and the low-pressure turbine 1 is installed above the condenser 12 via a foundation 20. In addition, a working overhead crane 108 is installed on the upper part of the turbine building 101.

  When a new low-pressure turbine 1 is replaced, first, the cores of the stationary parts such as the lower half inner casing 2, the lower half nozzle 5 and the upper half nozzle 6, and the dynamic parts such as the lower half casing rotor 3 and the blades 4. Make out.

  Then, the gap is adjusted so that the stationary part and the dynamic part do not come into contact with each other, and the assembly is performed in advance at an appropriate place other than the installation place.

  Thereafter, the assembled low-pressure turbine 1 is carried into the installation place, joined to the external casing of the existing low-pressure turbine, and the new replacement operation of the low-pressure turbine 1 is completed.

  As described above, according to the present embodiment, after the existing low-pressure turbine 1 is carried out from the installation position in the integrally assembled state, the newly manufactured low-pressure turbine 1 is subsequently carried in and installed in the integrally assembled state. Thus, the steam turbine can be replaced.

  Therefore, in the steam turbine replacement work, the construction period can be shortened by shortening the process, and the occupation time of the lifting equipment such as the overhead crane 108 can be shortened. It can be reduced and the plant operation rate can be improved.

[Third Embodiment] (FIGS. 1 to 4)
Next, a third embodiment of the present invention will be described with reference to FIGS. The present embodiment is a replacement method in which an existing low-pressure turbine is moved, loaded and installed in an assembled state at an adjacent work place. In addition, about the structure and process same as the said embodiment, description is abbreviate | omitted with reference to FIGS. 1-4.

  This embodiment is different from the second embodiment in that a temporary assembly place 14 having a sturdy floor at the same level as the installation place is provided adjacent to the low pressure turbine installation place, and replacement work is performed at this temporary assembly place 14. It is in.

  That is, the low-pressure turbine 1 is a high-speed rotating body, and centering adjustment work becomes important. In order to ensure the accuracy of the centering adjustment work, the floor and foundation at the assembly site are required to be robust.

  Therefore, in the present embodiment, as shown in FIG. 4, a temporary assembly place 14 is provided which is adjacent to the installation place and has a strong floor at the same level as the installation place. Take out and adjust.

  Then, the replacement low-pressure turbine 1 is carried into the place after the existing low-pressure turbine is removed and installed, thereby completing the new replacement operation.

  As shown in FIG. 4, the temporary assembly place 14 is a temporary building having the same configuration as that of the turbine building 11, and is installed adjacent to the side of the turbine building 11. It is as a configuration provided.

  According to this embodiment, it is not necessary to perform centering adjustment work at the installation location, and it is possible to provide a working method and a steam turbine that are easy to move.

[Fourth Embodiment] (FIGS. 1 to 3)
In the present embodiment, the disassembly of the low-pressure side internal casing 7 of the low-pressure turbine 1 and the assembly of the rotor 3 and the nozzles 5 and 6 incorporated in the internal casing 7 are performed at different locations. After the nozzles 5 and 6 are assembled, they are carried into the steam turbine 1 and the rotor 3 and the nozzles 5 and 6 are installed as an integrated structure.

  Then, the steam turbine is assembled at a location different from the installation location, and a public inspection is received at the location.

  In other words, the steam turbine is required to undergo an inspection (pre-use inspection) by the government office for all parts constituting the steam turbine at the time when the lower half passenger compartment is installed according to the Electricity Business Law.

  Since the lower external car compartment uses the existing car room, it will undergo pre-use inspection at the temporary assembly place adjacent to the installation place, and after passing, it will be assembled, centered and adjusted at the same place.

  According to this embodiment, it is possible to provide an efficient working method and a steam turbine that do not require an inspection period at the installation place by undergoing a pre-use inspection in advance at the temporary assembly place.

[Fifth Embodiment] (FIGS. 1 to 4)
This embodiment demonstrates the example which removes and carries out the existing low-pressure turbine 1 in an assembly state.

  That is, a place different from the installation place of the steam turbine is set as the installation place, the assembly work is performed at the assembly place having a strong floor for the assembly work, and the assembly work at the installation place can be omitted.

  A steam turbine is composed of a number of parts, and disassembling and removing an existing turbine requires a large work area and time for disassembly. However, as shown in FIG. A work place 22 having a temporary base 21 that is a strong floor at the same level is provided, and is removed and carried out in an assembled state.

  This eliminates the need for a large work area and shortens the time for disassembly. In addition, the radiation control area can be easily set.

  According to the present embodiment, it is possible to easily remove the existing steam turbine without requiring extra time and place.

  1. Steam turbine, 2. Lower half casing, 3. Lower half inner casing rotor, 4. Blades, 5. Lower half nozzle, 6. Upper half nozzle, 7. Internal casing, 8. External casing. 9. Upper half casing unit, 10. Internal casing side unit, 11 Turbine building, 12 Condenser, 13 Low pressure turbine, 14 Temporary assembly place, 20 ... Base stand, 21 ... Temporary base stand, 22 DESCRIPTION OF SYMBOLS Work place 101 Turbine building 102 High-pressure turbine 103 Low-pressure turbine 104 Generator 104 105 Condenser 106, 107 Shaft 108, 109 Overhead crane

Claims (6)

It comprises an upper half external compartment unit and an internal compartment, an upper half nozzle, a rotor and a lower half nozzle, which are assembled in advance, and are constructed by assembling these two units. Steam turbine for nuclear power plants. Nuclear power, characterized in that the existing steam turbine is carried out from the installation position in the state of being integrally assembled, and the steam turbine is subsequently replaced by carrying in and installing the newly produced steam turbine in the state of being integrally assembled. Replacement method for steam turbines for power plants. The disassembly of the low pressure side internal compartment and the assembly of the rotor and nozzle incorporated in the internal compartment are performed at different locations, and after assembling the rotor and nozzle, they are carried into the steam turbine. The method for replacing a steam turbine for a nuclear power plant according to claim 2, wherein the steam turbine is installed as an integral structure. The place where the steam turbine is installed is different from the installation place, the assembly work is performed at an assembly place having a solid floor for assembly work, and the assembly work at the installation place can be omitted. Replacement method for steam turbines for nuclear power plants. The method for replacing a steam turbine for a nuclear power plant according to claim 2, wherein the steam turbine is assembled at a location different from the installation location, and a public inspection is received at the location. The method for replacing a steam turbine for a nuclear power plant according to claim 2, wherein, when the steam turbine is replaced, the equipment to be replaced with the existing steam turbine is removed and carried out while being assembled.

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