WO2017146467A1

WO2017146467A1 - Construction apparatus for u-shaped nuclear reactor module pipe

Info

Publication number: WO2017146467A1
Application number: PCT/KR2017/001959
Authority: WO
Inventors: 문인득; 문선재
Original assignee: 문인득
Priority date: 2016-02-26
Filing date: 2017-02-22
Publication date: 2017-08-31
Also published as: KR101626270B1

Abstract

The present invention provides a construction apparatus, for a U-shaped nuclear reactor module pipe, for the construction of a nuclear reactor coolant pipe provided in a nuclear reactor coolant system. The apparatus comprises: a lower support which can ascend and descend vertically with respect to the floor by means of a plurality of hydraulic apparatuses; an upper support which is positioned on the lower support and has thereon a saddle for mounting a U-shaped module pipe; and a rotating tool which is for rotating the upper support with respect to the lower support, wherein the U-shaped module pipe is disposed between the lower end of a casing inlet port of a coolant pump of a nuclear reactor and an outlet pipe elbow of a steam generator, is aligned by means of rotation and ascent, and is connected by means of welding. Moreover, the present invention effectively inhibits welding shrinkage, which occurs during welding, by means of mounting a plurality of tie straps on the parts to be welded between the U-shaped module pipe, the lower end of the casing inlet port of the coolant pump and the outlet pipe elbow of the steam generator. And the welding is performed simultaneously on both the lower end of the casing inlet port of the coolant pump of the nuclear reactor and the outlet pipe elbow of the steam generator. Therefore, transverse shrinkage and angular distortion of the parts to be welded are completely prevented and thus precise welding can be performed.

Description

Reactor U type modular pipe construction device

The present invention relates to a construction device for the reactor coolant piping provided in the reactor coolant system facilities, and more specifically to the final connection section (Closure loop) of the core section of the CE type 2 LOOP reactor coolant piping by using a U-type piping module By welding in the field, the shrinkage stress due to welding does not extend in the lateral (horizontal) direction, but acts only in the longitudinal (vertical) direction, and by applying a tie strap to the weld connection, the hot pipe and the low temperature of the reactor coolant piping By minimizing the residual load due to the welding shrinkage deformation which exists after the connection welding between the final connection section of the pipe and the intermediate pipe, it is possible to prevent various vibrations generated during operation of the reactor coolant facility and contact wear between the various parts. To ensure stable operation of the reactor, to prevent equipment failure due to customs wear, and to increase the durability of the reactor The present invention relates to a reactor U-shaped module pipe construction device.

In general, nuclear power plants have been developed in Korea, for example, System Plus 80 (Hanbit 3, 4) of Conbustion Engineering (CE), Korean standard nuclear power plants (Hanul 3, 4, 5, 6 and Hanbit 5, 6), OPR1000 (Shin-Gori 1,2), APR1400 (Shin-Gori 3,4, Shin-Uljin 1,2, UAE Nuclear Power Plants 1-4), 2-loop Pressurized Water Reactor. A reactor power plant (hereinafter referred to simply as a "nuclear reactor") is a reactor coolant system (RCS) in a containment building, as described in Korean Patent Publication No. 10-1473665, "Pipe support device for replacing parts of a nuclear power plant." ) Is provided. Referring to Figure 1, the basic structure of such a nuclear power plant (hereinafter referred to simply as "nuclear reactor") is shown. Such a reactor 1 is equipped with a reactor coolant system (RCS) in a containment building. . This reactor coolant system has a reactor 5 containing a reactor at the center and at least one heat transfer circuit 7 connected thereto. In FIG. 1, two heat transfer circuits are shown connected in parallel to the reactor 5. Each circuit 7 comprises two steam generators 9 and at least one, usually four coolant pumps 11 for circulating coolant between the reactor 5 and the steam generator 9. Each circuit 7 includes three main pipes, the main pipe having a large diameter, connected to the main parts of the circuit. In addition, the circuit 7 includes a pressurizer (not shown) to keep the temperature and pressure of the coolant constant. The first large diameter pipe or hot leg 13 is a large diameter pipe of approximately 42 inches in diameter and is connected to one side of the reactor 5 and one suction side of the coolant chamber of the steam generator 9 so as to supply the reactor 5. The heated coolant in contact with the core in () is sent to the steam generator (9). The circulation pipe 15 called a cross-over leg connects one side of the discharge part of the coolant chamber of the steam generator 9 and one side of the vortex chamber suction part of the coolant pump 11. The cold leg 17 connects between the vortex chamber of the coolant pump 11 and the reactor 5. In addition, the coolant cooled in the steam generator 9 and drawn out by the coolant pump 11 is transmitted to the reactor 5 through the circulation pipe 15 and the low temperature pipe 17 to cool the core. In such a reactor, each steam generator 9 has its lower side fixedly supported by a number of stud anchors (not shown) on a sliding base (not shown), which sliding base is placed on a forged anchor plate. It is supported on a number of, for example, four hemispherical sliders provided to accommodate the minute left and right movements occurring during operation of the reactor. The conventional construction process of the reactor coolant piping provided in such a reactor coolant system equipment is as follows. That is, as shown in FIG. 2, after the arrangement of the reactor 5, two steam generators 9 and four coolant pumps 11, the high temperature connecting the outlet of the reactor 5 and the steam generator 9. First, connect the hot leg (P001, P010) by welding. In this case, the reactor 5 side is welded first, and the steam generator 9 side is welded later, and inner surface welding & stress relief heat treatment work (PWHT) is performed. Then, the first set of low temperature pipes P005 and P014 connecting the reactor 5 and the coolant pump 11 are aligned and welded together. Next, the 2nd set of low temperature pipes P009 and P018 which connect the reactor 5 and the coolant pump 11 are aligned, and welded. At this time, the casing, the vertical support and the crevis support of the coolant pump 11 are connected to the sliding base, and welding is performed. The installation guideline of the CE type reactor recommends the use of temporary supports instead of permanent supports when welding the reactor piping to the inlet and inlet sides of the coolant pump (11). The reason is to allow movement due to weld shrinkage and to leave no restraint on the pump support. This method was applied in Hanvit Units 3 and 4. However, the choice of installation method is specified in the installation manual by the contractor, and since then, it is common practice in the industry to apply the installation method using a permanent support. Such a low temperature pipe is welded while the casing of the reactor coolant pump 11 and the vertical column support are permanently installed before the welding, so that the inclination of the flange surface of the reactor coolant pump 11 to a certain degree of horizontal elevation is allowed. The center line of the four pumps 11 performs welding by compensating for the amount of welding shrinkage in advance. In case of manual welding, the longitudinal welding shrinkage is mostly 7 ~ 9mm, and when the welding technician recognizes the displacement and the displacement occurs, the welding work is instructed in the opposite direction and the construction method corresponding to the rotational shrinkage is applied. Welding is possible while compensating for. Orb ital automatic welding has a shrinkage range of 5 ~ 6mm, but the welding head rotates in one direction and continues welding, so the lateral (rotational) shrinkage occurs after the longitudinal shrinkage. As a result, the reactor coolant pump has an inclination characteristic that the horizontal altitude does not maintain the horizontal level of the initial installation state. Next, a first set of low temperature pipes P005 connecting the reactor 5 and the coolant pump 11 P014) and the stress relief heat treatment operation (PWHT) of the second set of low temperature pipes (P009, P018). Next, the elbows P004, P008, P013, and P017 are attached to the casing inlets of the coolant pump 11 for welding. Such a detailed structure is described in FIG. 3. That is, elbows P004, P008, P013, and P017 are attached to the lower end of the casing inlet of each coolant pump 11 to be welded to each other. At this time, the elbows P004, P008, P013, and P017 are welded on only one side, so there is no restraint. On the other hand, the elbows (P0 02, P006, P011, P015) on one side of the outlet tube of the steam generator (9) is first welded in an independent process, even when there is no restraint. When the elbow welding process is completed, in order to install the circulation pipe L-shaped spool of the remaining final connection pipe, measurement of the machining dimension is performed by surveying the connecting section by measurement, and the circulation pipe L-shaped spool (P003, P007, P012, P016) Is factory processed to fit the site. When field surveying is performed to process such conventional final connection L-shaped spools (P003, P007, P012, P016), the opposite side of the final connection L-shaped spools (P003, P007, P012, P016) as the pump container is tilted The rise of the outlet nozzle of the steam generator is found to be related to the inclination of the flange face of the pump vessel generated by cold tube welding. Therefore, to connect to the outlet nozzle of the steam generator (9) can not be the normal work alignment can be carried out in the field measurement and the final connection L-shaped spools (P003, P007, P012, P016) is processed after the alignment work. In this case, the empirical value of the processing amount on the outlet pipe side of the steam generator 9 is about 9 mm maximum for manual welding. In the case of automatic welding, a maximum of about 50 mm is required for the welding, and the slope of the flange of the pump container is manual. More automatic welding occurs. After finishing the alignment (FIT-UP) of these final connection L-shaped spools (P003, P007, P012, P016), weld the final connection L-shaped spools (P003, P007). Then, weld the final connection L-shaped spools (P012, P016). In this welding step, when the final connection L-shaped spools (P003, P007, P012, P016) and the elbows on the suction side of the pump 11 are welded to each other and the longitudinal shrinkage of 5 mm is welded, the steam generator 9 Weld welding with the exit side. Next, the final connection L-shaped spools (P003, P007, P012, P016) are welded exclusively and a stress relief heat treatment operation (PWHT) is performed. Next, a final survey is made after this final welding is completed, and the installation step of the reactor coolant pump horizontal support is performed. This process is the pipe construction of the conventional coolant piping system that has been applied to the CE type 2-LOOP reactor. However, such a conventional construction method, since the final contracted L-shaped spools (P003, P007, P012, P016) after the completion of the processing, the welding shrinkage must occur in a state that is completely constrained in the direction of the cold tube, this process, Excessive shrinkage stress occurred at, resulting in low temperature cracking during manual welding. In the welding part, if there are many welding constraints, it is common welding technology to prevent the low temperature cracking when the welding preheating temperature is higher than the technical standard in the welding part. However, since the coolant pump vertical column support is permanently installed, it does not exist only in the pipe welded part when welding shrinkage occurs, and because the vertical column support is fixed to the anchor bolt and constrained, it tries to cope with the shrinkage. The anchor bolt and the pump vertical support will remain. That is, in the conventional construction method, as shown in FIG. 5, when constructing the final connection L-shaped spools (P003, P007, P012, P016), elbows (P004, P008) installed on the lower end of the casing inlet of the coolant pump 11 , P013, P017, the welding line is formed in the vertical direction, the welding is performed, the welding line is formed in the horizontal direction in the elbow (P002, P006, P011, P015) of the outlet pipe side of the steam generator (9). Therefore, the longitudinal direction of the final connecting L-shaped spools (P003, P007, P012, P016) by the welding line in the vertical direction of the elbows (P004, P008, P013, P017) provided at the lower end of the casing inlet of the coolant pump (11). Direction), and the final connecting L-shaped spools (P003, P007, P012, P016) are formed by welding lines in the horizontal direction of the outlet pipe side elbows P002, P006, P011, and P015 of the steam generator 9). Weld shrinkage occurs in the vertical direction (longitudinal) of. In addition, another phenomenon to cope with the welding shrinkage affects the sliding base of the steam generator. In other words, a reaction force is applied to the sliding base of the steam generator 9 to cope with the welding shrinkage 5 mm generated during the connection between the nozzle side of the steam generator 9 and the intermediate tube, and the horizontal altitude of the sliding base skirt before and after welding is about 1 mm. Settles. In addition, although the stress is removed by the stress relief heat treatment work performed in the welded portion of the final connection L-shaped spool (P003, P007, P012, P016), the steam generator (9) nozzle of the stress relief heat treatment and the pump (11) The nozzle still has residual stress. That is, the settlement of the sliding base and the preload remaining in the pump vertical column support remain in the pump vertical column support even though the stress relief heat treatment is performed on the welded portion. This residual load is one cause of pipe movement during reactor operation.

In fact, Vectel Engineering, which performed the replacement work of the steam generator 9 of the US Milestone Point 2, failed to control the load remaining in the reactor coolant pump. The typical replacement period was around 80 days, but this milestone point 2 took 185 days, and the radiation exposure remained more than three times that of the conventional replacement project. In addition, if the residual load remains in the support of the reactor coolant pump 11 and the sliding base of the steam generator 9, it affects the thermal expansion behavior of the reactor coolant system during the high temperature functional test, and thus the upper support of the steam generator 9 Affects the high temperature clearance requirement to be maintained between the key / keyway (not shown), and also the pin-to-pin distance between the room temperature (before heat-up and after cool-own) of the SNUBBER. pin) exceeds the design criteria. In addition, vibration occurs during normal operation of the reactor, so that the customs wear of the steam generator 9 occurs from the beginning of commercial operation. And severe cases will cause high vibration in the reactor coolant pump (11). As described above, the problems caused by the conventional reactor coolant piping construction include longitudinal contraction and lateral contraction at the welds of the final connection L-shaped spools (P003, P007, P012, P016), and in the process, the lower support structure of the steam generator (9). And a spring back force remains in the vertical column of the coolant pump 11. That is, in the conventional process, since the welding is performed to the inlet pipe and the outlet pipe of the reactor coolant pump 11 using the permanent support, the restraining force remains. Therefore, the conventional process affects the horizontal altitude of the pump casing due to the action of the restraint force, and if a defect occurs in the welded part, local shrinkage occurs due to repair welding, resulting in the horizontal altitude of the pump casing being out of the design standard value. . As a result of these residual loads, welding the final connecting L-shaped spools (P003, P007, P012, P016) generates a compressive load due to shrinkage on the sliding base, causing settlement. This settlement increases the friction between the slider and the base plate. This settlement can be seen as the load remaining on the sliding base. This residual load increases the frictional force of the slider in the initial stage of the reactor, thereby significantly inhibiting the lateral sliding operation. That is, the sliding base is a design requirement that must meet the installation tolerance (within level tolerance + /-0.889mm). However, in the connecting welding of the final connecting L-shaped spools (P003, P007, P012, P016), the welding contraction force in the vertical direction (longitudinal direction) acts as a compressive force on the sliding base because two welding is performed at the same time. In this welding process, the welding shrinkage causes a welding displacement of about 0.9 to 1.1 mm in the negative direction (-) in the vertical direction (longitudinal direction) due to the welding shrinkage, which remains as a compressive force on the sliding base. This compressive force has the characteristic of suppressing slippage in the lateral direction (horizontal direction) by increasing the frictional force at the initial stage of starting. As a result, the conventional reactor coolant pipe welding weld is provided with a permanent support (vertical column support) of the reactor coolant pump 11, the low temperature pipe is welded, and the final connection L-shaped spools (P003, P007, P012, P016) are removed. In the case of welding, the phenomenon that residual load exists in the lower support of the steam generator 9 and the vertical column support of the reactor coolant pump 11 cannot be avoided. Therefore, if the sliding base is deformed and tilted, it is not possible to keep the level, resulting in an additional stress of vibration due to the deformation and interference of the associated support structure of the reactor coolant pump 11 and the steam generator 9. This vibration stress not only causes the tubular wear of the steam generator 9, but also causes the stress corrosion cracking of the tubules by increasing the stress on the tube (tubule) surface. It also adds fatigue to piping connected to the RCS system. Long periods of operation in this state lead to internal wear of the reactor coolant pump and leakage of the mechanical seal and small diameter piping of the reactor coolant pump. On the other hand, the welding construction of the reactor coolant pipe is a welding joint with shrinkage and deformation, rather than simply viewed as a weld, there is a need to manage it at a precise mechanical joint level. In other words, the importance of construction technology to realize the design purpose cannot be said in words, but the guidelines recommended by the original designer's installation guideline correspond to the manual welding guidelines. There is a part that needs to be supplemented by some process or construction technology because it is not considered. The Construction Manual recommends that two people carry out balance welding at the same time in opposite locations only when welding hot tubes. However, in automatic welding, the welding head is rotated in one direction, and almost all of them are applied, resulting in a problem caused by the failure of lateral contraction (circumferential) control. That is, since the kinematic operation characteristics of the RCS system due to the non-destructive quality of the welded parts are so biased, the automatic operation of the steam generator 9 and the coolant pump 11 is applied since the automatic welding is applied. There are many problems that deviate from the true position, and device vibration problems often occur, so the development of more precise welding construction technology according to the automatic welding application is urgently needed. Therefore, there is an urgent need in the art to develop a technology capable of minimizing the structural vibration of the reactor to prevent the tubular wear of the steam generator and the wear of the reactor coolant system equipment.

An object of the present invention is to solve the conventional problems as described above, when the new reactor piping construction, sliding of the steam generator support structure generated by the welding shrinkage of the high-temperature pipe, low-temperature pipe, intermediate pipe closure loop (closure loop) It provides a reactor U-shaped module factory that can prevent the settlement of the base, prevent the operation mismatch of the slider, and prevent structural vibration of the reactor coolant pump and wear of the steam generator tubing. In addition, another object of the present invention is that when the plant or field processing of the U-shaped module tube is completed, the operator can make a final alignment very easily between the lower end of the casing inlet of the coolant pump and the outlet pipe elbow of the steam generator, U Tie straps are attached to the weld connection between the type module tube and the lower end of the casing inlet of the coolant pump and the outlet pipe elbow of the steam generator to suppress welding shrinkage during welding operation. Welded connection through orbital automatic welding provides a reactor U-shaped modular tube factory that prevents transverse shrinkage and torsional distorsion of the welded portion, enabling precise weld construction. Is in.

In order to achieve the above object, the present invention is an apparatus for constructing a reactor coolant pipe provided in the reactor coolant system, comprising: a lower support configured to move up and down with respect to the floor by a plurality of hydraulic devices; An upper support positioned on an upper side of the lower support, the upper support having a saddle for mounting a U-shaped module tube; And a rotation mechanism configured to rotate the upper support relative to the lower support, wherein the U-shaped module tube is disposed between the lower end of the casing inlet of the coolant pump of the reactor and the outlet tube elbow of the steam generator, and It provides reactor U-shaped module tubular factory used to raise and align and weld connections. In addition, the present invention preferably, the rotating mechanism includes a circular rail fixed to the upper surface of the lower support, and a plurality of wheels fixed to the lower surface of the upper support, the wheels are disposed on the circular rail is circular By moving along the rail, it allows 360 degree rotation of the upper support with respect to the lower support, and rotates the U-shaped module pipe of the upper support under the casing inlet of the coolant pump of the reactor and under the outlet pipe elbow of the steam generator. It is configured to. And the present invention is preferably, the upper support is configured to surround the U-shaped module tube with a plurality of turn buckle and rubber plate on the saddle to fix the U-shaped module tube, the upper, lower support for the side hook A number of lifting lugs are formed to move the upper and lower supports. In addition, the present invention preferably, one side of the U-shaped module pipe, the lower end of the casing inlet welding connection of the coolant pump of the reactor, the other side of the U-shaped module pipe, the welding connection of the outlet pipe elbow of the steam generator The site includes a plurality of tie straps that are fixed to prevent weld shrinkage during welding. And the present invention preferably, the plurality of tie straps, one side of the U-shaped module tube, the inside of the casing inlet lower welding connection portion of the coolant pump of the reactor, the other side of the U-shaped module tube, the steam Inside the welding connection part of the outlet pipe elbow of the generator, the tie strap is fixed to the welding groove at the circumferentially equal intervals so as to be restrained from shrinking by screwing, and after the external welding of the welding connection part is completed, the U-shaped module It is removed from the weld connection between the tube and the lower end of the casing inlet of the coolant pump of the reactor and the outlet tube elbow of the steam generator. In addition, the present invention preferably, the plurality of tie straps, each of the inside of the welding connection portion, the one side of the U-shaped module tube, and the lower end of the casing inlet of the coolant pump of the reactor, or the U-shaped module The other side of the pipe and the outlet pipe elbow of the steam generator is welded and connected, each middle of the tie strap between the one side of the U-shaped module pipe and the improved groove between the lower end of the casing inlet of the coolant pump of the reactor, the U By forming a wedge-shaped step which is respectively inserted into the improvement groove between the other side of the type module tube and the outlet tube elbow of the steam generator, it is configured to minimize the welding shrinkage during the welding operation.

And the present invention preferably, one side of the U-shaped module tube, the lower end of the casing inlet welding connection of the coolant pump of the reactor, the other side of the U-shaped module tube, the welding connection of the outlet pipe elbow of the steam generator The site is welded and completed at the same time by using a tie strap to suppress the welding shrinkage of the narrowing GTAW, which is rotated and welded along the orbital track, respectively.

According to the reactor U-shaped module tube construction device according to the present invention, when the plant or field processing of the U-shaped module tube is completed, it is mounted on the saddle of the upper support, and in this state, the lower end of the casing inlet of the coolant pump of the reactor, It may be used to rotate and elevate between the outlet tube elbows of the steam generator for final alignment and to weld weld. In addition, according to the present invention, a plurality of tie straps are attached to the welding connection portion between the U-shaped module tube, the lower end of the casing inlet of the coolant pump, and the outlet tube elbow of the steam generator, thereby effectively suppressing the welding shrinkage occurring during the welding operation. The welding work takes place simultaneously at the bottom of the casing inlet of the coolant pump of the reactor and at the elbow side of the outlet pipe of the steam generator. It can be prevented to achieve precise welding construction. Therefore, the present invention prevents the settlement of the sliding base, which is a steam generator support structure, caused by welding shrinkage of the hot pipe, the cold pipe, and the intermediate pipe closure loop during the reactor pipe construction, and prevents the operation mismatch of the slider. Improved to prevent the structural vibration of the reactor coolant pump and the steam generator customs wear, and to prevent the contact wear between the various parts, to ensure the stable operation of the reactor, to prevent equipment failure, and to increase the endurance life of the reactor The effect can be obtained.

FIG. 1 is an external perspective view showing a reactor coolant system (RCS) including a reactor of a reactor, a steam generator, and coolant pumps.

FIG. 2 is a plan sectional view showing a reactor coolant system (RCS) including a reactor of a reactor, a steam generator and coolant pumps.

3 is an explanatory view of connecting the final connecting L-shaped spool between the elbow of the suction side of the coolant pump and the outlet elbow of the steam generator according to the conventional art.

Figure 4 is a side view as a whole showing a reactor U-type module tube factory in accordance with the present invention.

5 is a longitudinal sectional view showing a reactor U-shaped module tube factory of the present invention, and is a cross-sectional view along the line A-A of FIG.

Figure 6a is a plan view showing the position where the wheel is disposed on the circular rail of the lower support in the reactor U-shaped module tube construction apparatus according to the present invention.

Figure 6b is a side cross-sectional view showing the position of the wheel on the circular rail in the reactor U-shaped module tube construction apparatus according to the present invention.

Figure 7 is a cross-sectional view showing the mounting structure of the tie strap installed in the reactor U-shaped module tube construction apparatus according to the present invention.

8 is a cross-sectional view for explaining the arrangement structure and two simultaneous welding of tie straps installed in the weld connection portion in the reactor U-shaped module tube construction device according to the present invention.

9A and 9B are explanatory diagrams and result graphs of the test pieces used in the tie strap modeling experiment of the reactor U-shaped module tube construction device according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. Reactor U-shaped module tube construction apparatus 100 according to the present invention, as shown in Figure 4 as a whole, the lower end of the casing inlet of the coolant pump 11 of the reactor, the outlet pipe elbow (P002, of the steam generator 9) Between P006, P011 and P015, place U-shaped modular pipes (P003 + P00 4), (P007 + P008), (P012 + P013), and (P016 + P017), rotate and raise them to align, and weld Is the device used to. The U-shaped module tube is welded at the same time between four coolant pumps 11 and two steam generators 9, as indicated in relation to FIG. That is, the U-shaped module tube has four U-shaped module tubes (P003 + P004), (P007 + P008), (P012 + P013), and (P016), as shown in FIG. 2, in order to maintain the balance of welding. Weld + P017) at the same time. As such, when four welding is performed at the same time, the welding heads are rotated in opposite directions to be balanced in a loop symmetrical with each other about the reactor 5 in a symmetrical loop, thereby preventing rotational shrinkage. Reactor U-shaped modular tube construction apparatus 100 according to the present invention has a lower support 110 configured to be able to move up and down with respect to the floor 108 by a plurality of hydraulic devices 106. The lower support 110 is made of, for example, a steel structure, the hydraulic device 106, for example, six are mounted below the lower support 110, through which the lower support 110 of the win , The descent takes place. In addition, this lower support 110 may be used as a hooking means when a plurality of lifting lugs 114 are formed on the side thereof to move the lower support 110. In addition, an upper support 130 is provided at an upper side of the lower support 110. The upper support 130 is provided with saddles 140 for mounting U-shaped module pipes (P003 + P004), (P007 + P008), (P012 + P013), and (P016 + P017), respectively. As the lower support 110, for example, it is made of a steel structure, a plurality of lifting lugs 134 are formed on the side thereof can be used as a hook means when moving the upper support 130. In addition, the saddle 140 located on the upper portion of the upper support 130, as shown in Figure 5, to form an arc-shaped inclined surface on the upper surface of the U-shaped module tube (P003 + P004), (P007 + P008 ), (P012 + P013) and (P016 + P017) are seated. In addition, these saddles 140 are upper and both sides thereof, as shown in Figs. 4 and 5, respectively, a plurality of turn buckle 144 is fixed, the turn buckle 144 is a wire rope 146 is U-shaped modular pipe (P003 + P0 04), (P007 + P008), (P012 + P013), (P016 + P017) is configured to enclose U-shaped modular pipe (P003 + P004), (P00 7 + P008) Fix (P012 + P013) and (P016 + P017). At this time, when the wire rope 146 of the turn buckle 144 surrounds the U-shaped module pipes (P003 + P004), (P007 + P008), (P012 + P013), and (P016 + P017), the U-shaped module pipes In order to prevent surface damage of (P003 + P004), (P007 + P008), (P012 + P013), (P016 + P017), a rubber plate 148 is inserted between the wire rope 146 and the U-shaped module tube. This rubber plate 148 not only prevents the wire rope 146 from scratching the U-shaped modular pipes (P003 + P004), (P007 + P008), (P012 + P013), and (P016 + P017). It prevents slipping between metal materials to ensure perfect fixing. In addition, the reactor U-shaped module tube construction apparatus 100 according to the present invention, a rotating mechanism configured to rotate the upper support 130 with respect to the lower support 110 between the upper and lower support (110, 130) ( 170 is disposed. As shown in FIGS. 6A and 6B, the rotating mechanism 170 includes a circular rail 172 fixed to the upper surface of the lower support 110 and a plurality of fixed to the lower surface of the upper support 130. Wheels 174. Such a rotation mechanism 170 is disposed on the circular rail 172 at equal intervals in the circumferential direction along the circular rail 172, as shown in FIG. 6A, preferably on the circular rail 172. And is configured to roll along the circular rail 172. In such a structure, the rail 172 forms a "curve" groove in which its upper surface is concave, and the wheels 174 roll along the concave "curve" groove of the rail 172. These wheels 174 may be equipped with a needle bearing (not shown) to facilitate their rotation. Thus, such a rotary sphere 170 allows the 360 degree rotation of the upper support 130 with respect to the lower support 110, and consequently the U-shaped module tube (P003 + P004) to the saddle 140 on the upper support 130. ), (P007 + P0 08), (P012 + P013), (P016 + P017) is fixed, the U-shaped module tube (P003 + P004), (P007 + P0 08), (P012 + P013), (P016 + P017) can be rotated 360 degrees below the casing inlet of the coolant pump 11 of the reactor and below the outlet pipe elbows P002, P006, P011, P015 of the steam generator 9. In addition, the reactor U-shaped module tube construction apparatus 100 according to the present invention, one side of the U-type module tube, the casing inlet bottom welding connection portion of the coolant pump 11 of the reactor, and the other side of the U-type module tube And, the welding connection of the outlet pipe elbow (P002, P006, P011, P015) of the steam generator (9), a plurality of tie straps 190 for preventing welding shrinkage during the welding operation. The mounting structure of this tie strap 190 is shown in FIG. That is, the tie strap 190, the one side of the U-shaped module tube, the inside of the casing inlet lower welding connection portion of the coolant pump 11 of the reactor, the other side of the U-shaped module tube, the steam generator ( The welding is fixed inside the welding connection of the outlet pipe elbow (P002, P006, P011, P015) of 9). As shown in FIG. 8, each of the tie wraps 190 is provided at one side of the U-shaped module tube and at the lower end of the casing inlet of the coolant pump 11 of the reactor. For example, welding is performed at eight places at equal intervals of 45 degrees in the circumferential direction, respectively. The other side of the U-shaped module pipe and the inside of the outlet pipe elbows P002, P006, P011, and P015 of the steam generator 9, for example, are welded at eight locations at equal intervals of 45 degrees in the circumferential direction, for example. do. The tie strap 190 is connected to a structure different from the tack welding of the temporary fixing jig used in a typical large diameter welding operation. That is, the tie strap 190 used in the present invention has a stepped portion corresponding to the improvement groove 192 between one side of the U-shaped module tube and a lower end of the casing inlet of the coolant pump 11 of the reactor, respectively. 194 to be precision machined. Similarly, the tie strap 190 is inserted into the improvement groove 192 between the other side of the U-shaped module tube and the outlet pipe elbows P002, P006, P011, P015 of the steam generator 9, respectively. It has a wedge-shaped step 194. In addition, the tie strap 190 is connected to the complete total welding along the entire length of both sides, unlike the temporary welding (Tack-welding) of the temporary fixing jig. That is, in general, the temporary welding jig of the temporary fixing jig (Tack-welding) operation, U-shaped module pipe (P003 + P004), (P007 + P008), (P012 + P013), (P016 +) to which the present invention is applied In the welding connection of P017, the tie strap 190 is connected in a complete overall welding manner since it cannot withstand its welding shrinkage. In the process of connecting the tie strap 190, the middle step 194 of the tie straps 19 0, the improved groove (between one side of the U-shaped module tube and the lower end of the casing inlet of the coolant pump 11 of the reactor ( 192, and in contact with the other side of the U-shaped module tube and the improvement groove 192 between the outlet pipe elbows P002, P006, P011, P015 of the steam generator 9, respectively. As such, the U-shaped module tube (P003 + P004), (P007 + P008), (P012 + P013), (P016 + P017) is configured to minimize the welding shrinkage during the welding connection operation. Reactor U-shaped module tube construction apparatus 100 according to the present invention configured as described above, the installation of the U-shaped module tube (P003 + P004), (P007 + P008), (P012 + P013), (P016 + P017) What should be done beforehand is that the reactor must be completely fixed in advance so that it will not move under any conditions. The U-shaped modular tubes can each be prefabricated at the factory or in the field. The U-shaped module tube is precisely field- or factory-processed while comparing the final loop section with values measured at four locations. In addition, during the manufacturing of the U-shaped module tube, the welding while monitoring the longitudinal shrinkage and rotational shrinkage during welding to match the measured spool length. At this time, alignment lugs are attached to each inner surface of the pipe and welded, and then stress relief heat treatment (PWHT) is performed. By preparing the U-shaped module tube in this way, it is possible to eliminate the process of reprocessing and reloading the factory processing process of the final connected L-shaped spools (P003, P007, P012, P016) different from the design dimensions. On the other hand, in order to maintain the balance of welding, such a U-shaped module tube, as shown in relation to Figure 2, between the four coolant pump 11 and the two steam generators (9) P003 + P004), (P007 + P008), (P012 + P013) and (P016 + P017) are welded simultaneously. At this time, the reactor U-shaped module tube construction apparatus 100 according to the present invention, as shown in Figure 4 as a whole, each U-shaped module tube (P003 + P004), the saddle 140 of the upper support 130, (P007 + P008), (P012 + P013), and (P016 + P017), the lower end of the casing inlet of the coolant pump 11 of the reactor and the outlet pipe elbows of the steam generator 9 (P002, P006, P011, P015) respectively. At this time, the height of the U-shaped module tube is lower than the height of the casing inlet of the coolant pump 11 of the reactor and the outlet pipe elbows P002, P006, P011, P015 of the steam generator 9, U Both ends of the modular module tube are not aligned with the lower end of the casing inlet of the coolant pump 11 of the reactor and the outlet pipe elbows P002, P006, P011, P015 of the steam generator 9. For example, it is a state arrange | positioned at about 90 degree shift. In this state, the operator uses the rotary mechanism 170 to operate the reactor at both ends of the U-shaped module pipes (P003 + P004), (P007 + P008), (P012 + P013), and (P0 16 + P 0 17). Rotate the U-shaped module tube to align the lower end of the casing inlet of the coolant pump 11 with the outlet pipe elbows P002, P006, P011, P015 of the steam generator 9. At this time, the rotation mechanism 170 is a wheel 174 of the upper support 130 is rotated along the circular rail 172 of the lower support 110, U-shaped module pipe (P003 + P004), (P007 + P008), The rotation of (P012 + P013) and (P016 + P017) is as described above. Then, U-shaped module pipes (P 003 + P004), (P007 + P008), (P012 + P013), and (P016 + P017) are lifted up using the hydraulic device 106 provided on the lower support 110. Let's do it. At this time, the hydraulic device 106, as well as raising and lowering both the upper and lower support (110, 130) and the U-shaped module tube thereon. Thus, the U-shaped module pipes (P003 + P004), (P007 + P008), (P012 + P013), and (P016 + P017) are raised to lower the casing inlet of the coolant pump 11 of the reactor and the outlet of the steam generator 9 When it is finally aligned with the tube elbows (P002, P006, P011, P015), a tie wrap inside the U-shaped module tubes (P003 + P004), (P007 + P008), (P012 + P013), (P016 + P017) Mounting of 190 is made. That is, by using a tie strap 190 specially configured in the present invention, as shown in Figures 7 and 8, one side of the U-shaped module tube and the lower end of the casing inlet of the coolant pump 11 of the reactor The inner side is welded 8 places at equal intervals of 45 degree circumference, respectively. The other side of the U-shaped module tube and the inside of the outlet pipe elbows P002, P006, P011, and P015 of the steam generator 9 are welded at eight locations at equal intervals of 45 degrees in the circumferential direction, respectively. Then, after the fixing by the tie strap 190 is made, as shown in Figure 8, one side of the U-shaped module tube, the casing inlet bottom welding connection of the coolant pump 11 of the reactor, The welding side of the other side of the U-shaped module tube and the outlet pipe elbows P002, P006, P011, P015 of the steam generator 9 are simultaneously welded by a TIG automatic welding device. In this way, in the two welding sites W1 and W2 of FIG. 8, when a welding connection is made through orbital automatic welding at the same time, the transverse shrinkage of the welding portion, and the angular distortion Precision welding construction can be achieved by completely preventing the deformation (Angular distorsion). The orbital automatic welding may be made of, for example, a TIG automatic welding device. Then, in the welding operation, when the welding 7 to 8 pass of the welding connection is made, the turn buckle 144 fixing the U-shaped module tube is removed, and the welding shrinkage occurring in the subsequent welding pass is tied. Strap 190 completely prevents the welding shrinkage does not occur. In addition, one side of the U-shaped module tube, the outer welding of the lower casing inlet welding connection portion of the coolant pump 11 of the reactor, the other side of the U-shaped module tube, and the outlet of the steam generator 9 When the outer welding of the weld connection of the pipe elbows (P002, P006, P011, P015) is completed at the same time, the tie straps 190 are respectively U-shaped module pipe (P003 + P004), (P007 + P008), (P012 + P013), (P016 + P017), the lower end of the casing inlet of the coolant pump 11 of the reactor, and the outlet pipe elbows P002, P006, P011, P015 of the steam generator 9 are removed. At this time, the welding connection part of the tie strap 190 is ground by grinding and blown with a hammer to blow the U-shaped module tube, the lower end of the casing inlet of the coolant pump 11 of the reactor, and the steam generator 9. It is separated from the outlet pipe elbows (P002, P006, P011, P015). When the tie strap 190 is separated in this way, the improvement groove 192 between one side of the U-shaped module tube and the lower end of the casing inlet of the coolant pump 11 of the reactor is exposed, and the other side of the U-shaped module tube, Improvement grooves 192 between the outlet pipe elbows P002, P006, P011, and P015 of the steam generator 9 are exposed, respectively. The improvement grooves 192 are simultaneously subjected to orbital automatic welding. Through the inner welding connection is made. Then, after the inner welding of the improvement grooves 192 is made, U-shaped module pipes (P003 + P004), (P007 + P008), (P012 + P013), (P016 + P017), and the coolant pump of the reactor ( The stainless clad layer 196 formed on the lower end of the casing inlet of 11) and the inner surface of the outlet pipe elbows P002, P006, P011, and P015 of the steam generator 9 is welded with the same stainless steel material to complete welding. This stainless clad layer 196 is used to enhance the corrosion resistance of the U-shaped module tube, the bottom of the casing inlet of the coolant pump 11 of the reactor, and the outlet pipe elbows P002, P006, P011, P015 of the steam generator 9. It is a double coated part on the inner side. Experimental Examples In the following, a series of experiments were conducted to demonstrate the effect of the tie strap 190 used in the present invention. First, the tie strap 190 is to minimize the welding shrinkage, conventionally, the tie strap 190 is not used in actual reactor pipe welding. However, in the present invention, a plurality of tie straps 190 are introduced at the welded connections of the respective U-shaped tube tubes P003 + P004, P007 + P008, P012 + P013, and P016 + P017. Table 1 below shows the inner shrinkage result using the tie strap 190. Table 1 compares the two, when the tie strap 190 is removed after 1/3 pass welding (19 pass) of each weld connection, and the tie strap 190 is removed after 100% welding (108 pass). Weld shrinkage of each reactor pipe is shown.

Table 1

<b>(</b> Table 1) Weight and Weld Shrinkage by Reactor Piping Position (Measurement and Modeling)

	A hot tube		Middle tube
	Vertical	horizontal	X, Z direction	Vertical
Dead weight (lbs)	20,000	10,000	10,000	25,000
19 Weld shrinkage (mm) of inner and outer surfaces with tie straps (190) attached during PASS welding	* Inside-average 1.5mm (measured), 1.9mm (modeling calculated) * Outside-average 3.0mm (measured), 2.6mm (modeling calculated)
108 Weld shrinkage (mm) of inner and outer surfaces with tie straps (190) attached after completing PASS welding	* Inner surface- Average 2,2 mm (measured) 2.23mm (modeling calculated value) * Outer surface shrinkage is a sinking phenomenon in final welding completion stage due to yielding phenomenon.

As can be seen from the measurement and modeling experiment of the weld shrinkage, it was more effective to remove the tie strap 190 after 100% welding of the welded portion.

Next, an unrestrained condition of the prior art without using the tie strap 190 and a restrained condition of the present invention using the tie strap 190 were compared. For thick and large diameter butt joints, such as reactor piping, restraint during welding, base material thickness, heat input, improved shape, bead welding method, and preheating affect weld shrinkage. Experience has shown that there are cases of low temperature cracking during the construction of reactor piping with manual welding, and that they do not appear immediately after welding at the temporary attachment site, but are detected as defects in the pre-operation inspection conducted after the room temperature test in the field. This phenomenon is mainly caused by the residual stress due to welding shrinkage due to welding heat input and restraint characteristics. In the reactor pipe welding operation, the welding crack, the vibration after the final construction, the positional accuracy, etc. are greatly influenced by the welding shrinkage, and the welding shrinkage depends on the constraint condition. There is a need to experiment by dividing into a restrained condition (invention) and an unrestrained condition (prior art) in which the tie strap 190 is not used. In this experiment, the reactor coolant, using a Leggatt Model that can be applied to large diameter pipes, such as reactor pipes, among the various modeling equations for weld shrinkage mentioned in the Predictive formula for weld distortion-a critical review (G VERBAEGHE). The conventional construction method and the improvement method of this invention were compared with respect to the distortion by welding position of the piping. The Leggatt Model is represented by Equation (1) below with respect to FIG. 9A showing the structure of the welded portion.

(Equation 1)

Where: δt; transverse shrinkage (mm)

q / v: heating Input (J / mm)

tc: thickness of unfused plate material (See Fig. 2)

β; restrained angular distortion (°)

d: distance between center of welded area and the center of the plate (mm). In Leggatt (Equation 1) of the hot tube welded part, a modeling result without using the conventional unrestrained condition, that is, the tie strap 190, was obtained as follows.

In addition, the actual measurement of the conventional unrestrained condition was the same as the graph shown in FIG. 9B. That is, according to the conventional construction method, the welding shrinkage (δ) in the 18 pass state of the weld site was approximately 5.7 mm. In addition, in the graph of FIG. 9B, the transverse shrinkage of the welded portion and the angular distors ion are calculated using the Leggatt model equation (Equation 1) for the conventional unrestrained condition. And measurements showed good agreement with each other. In the present experiment, modeling results were obtained for the restrained condition of the present invention to which the tie strap 190 was applied. Reactor U-shaped module tube construction apparatus 100 of the present invention has a characteristic that can significantly reduce the transverse shrinkage, and angular distant by attaching a tie strap 190, weld shrinkage By attaching this vertical only feature and the inner tie strap 190, it is possible to eliminate the angular distors ion, so it is assumed that β = 0 ° in (Equation 1), and (Equation 1) Can be simplified as (Equation 2) below.

(Equation-2)

Equation (2) can fully calculate the transverse shrinkage without computer analysis, provided that there is no angular distorsion, and only the heat input and the welding thickness are accurately controlled. Importantly, it is important to derive a variable that can precisely control the welded part and apply it without changing the variable. The equation (2) was calculated by applying the procedure (Procedure Qualification) record of the new nuclear power plant (APR 1400), and it was found that the model and the actual measured value is almost the same. The contraction data for each welding pass with the tie strap 190 applied to the APR 1400 are shown in Table 2 below. (Table 2) Shrinkage value by the improved modeling formula of Equation 2 (1 ~ 19 pass same heat input, welding thickness applied)

-------------------------------------------------- -------------------

Modeling Transverse shrinkage

-------------------------------------------------- -------------------

1pass

= 0.138 mm

2pass

= 0.138 mm

3pass

= 0.138 mm

4pass

= 0.138 mm

5pass

= 0.138 mm

6pass

= 0.138 mm

7pass

= 0.138 mm

8pass

= 0.138 mm

9pass

= 0.138 mm

10pass

= 0.138 mm

11pass

= 0.138 mm

12pass

= 0.138 mm

13pass

= 0.138 mm

14pass

= 0.138 mm

15pass

= 0.138 mm

16pass

= 0.138 mm

17pass

= 0.138 mm

18pass

= 0.138 mm 18 pass shrinkage 2.4 mm

19pass

= 0.138 mm

개량 LIGGATT Model = 2.62mm Improved LIGGATT Model = 2.62mm

Shrinkage value by the improved modeling formula of the said Formula 2 was weld shrinkage (delta) = 2.4mm after 18 pass of a weld site | part. As in the comparative experiment above, the weld shrinkage δ of the prior art unrestrained condition without using the tie strap 190 is 5.7 mm, but the constraint of the present invention using the tie strap 190 is The weld shrinkage (δ) of the stressed condition was 2.4 mm, and the difference of 1-18 pass shrinkage was 5.7 mm / 2.4 mm. Thus, the present invention has an effect of preventing weld shrinkage by more than 50% compared to the prior art. In addition, tie straps can be used to suppress welding shrinkage by applying the same to high and low temperature pipes that do not use U-shaped modular pipes.In the steam generator replacement business, the tie straps are reconnected to the steam generator after cutting 2, 3, and 4 cuts of the weld. It can be used on the inner surface of pipe to suppress welding shrinkage in welding. According to the reactor U-shaped module pipe factory 100 according to the present invention as described above, it is possible to achieve precise welding construction by completely preventing the transverse shrinkage, and torsional distorsion of the welded portion. have. Accordingly, the present invention prevents the settlement of the sliding base, which is the support structure of the steam generator 9, generated due to welding shrinkage of the hot pipe, the low temperature pipe, and the intermediate pipe closure loop during the reactor pipe construction. It is possible to prevent misoperation of the reactor, to prevent structural vibration of the reactor coolant pump (11) and to prevent abrasion of the steam generator (9), and to prevent contact abrasion between various components. And improved effects of increasing the reactor and lifetime of the reactor can be obtained. Although the present invention has been described in detail with reference to the accompanying drawings, the present invention is not limited to such a specific structure. Those skilled in the art may variously modify or change the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. For example, the rotating mechanism 170 may be a circular rail 172 and any 360-degree rotating shaft structure of the deformation structure other than the plurality of wheels 174, that is, the upper support 130 with respect to the lower support 110. It could also be done. In addition, the tie straps 190 may not be mounted at eight locations in the welding connection portion, but may be mounted in any other numbered intervals and in any equidistant arrangement. Nevertheless, it is intended that such simple design modification structures clearly fall within the scope of the present invention.

[Description of the code]

1: reactor 5: reactor

7: heat transfer circuit 9: steam generator

11: coolant pump 13: hot leg

15: circulation tube 17: cold leg

100: reactor U-shaped module tube construction apparatus according to the present invention

106: hydraulic system 108: bottom

110: lower support 114, 134: lifting lugs

130: upper support 140: saddle

144: turn buckle 146: wire rope

148: rubber plate 170: rotating mechanism

172: round rail 174: wheel

190: tie strap 192: improved home

194: stepped W1, W2: welded portion

P001, P010: High temperature tube

P005, P009, P014, P018: low temperature pipe

P002, P004, P006, P008, P011, P013, P015, P017: Elbow

P003, P007, P012, P016: L shaped spool

P003 + P004, P007 + P008, P012 + P013, P016 + P017: U type module tube

Claims

In the apparatus for constructing the reactor coolant piping provided in the reactor coolant system equipment,

A lower support configured to be liftable up and down relative to the floor by a plurality of hydraulic devices;

An upper support positioned on an upper side of the lower support, the upper support having a saddle for mounting a U-shaped module tube; And

To prevent welding shrinkage during the welding operation in one side of the U-shaped module tube and the lower end of the casing inlet welding connection of the coolant pump of the reactor, and the other side of the U-shaped module tube and the weld connection of the outlet pipe elbow of the steam generator. A plurality of tie straps secured for; And

And a rotating mechanism configured to rotate the upper support relative to the lower support.

The U-shaped module tube is disposed between the lower end of the casing inlet of the coolant pump of the reactor and the outlet tube elbow of the steam generator, rotated and raised to align, and welded to each other. A wedge-shaped step that is inserted in correspondence with an improvement groove between one side of the tube and a lower end of the casing inlet of the coolant pump of the reactor, and the improvement groove between the other side of the U-shaped module tube and the outlet pipe elbow of the steam generator. Reactor U-shaped tube construction apparatus, characterized in that configured to minimize the welding shrinkage during welding operation by forming a surface.
According to claim 1, The rotating mechanism includes a circular rail fixed to the upper surface of the lower support, and a plurality of wheels fixed to the lower surface of the upper support, the wheels are disposed on the circular rail to form a circular rail Thus, by moving, allowing 360 degree rotation of the upper support relative to the lower support and rotating the U-shaped module pipe of the upper support to the lower end of the casing inlet of the coolant pump of the reactor and the lower part of the outlet pipe elbow of the steam generator. Reactor U-shaped modular tube construction apparatus, characterized in that consisting of.
According to claim 2, wherein the upper support is configured to surround the U-shaped module tube with a plurality of turn buckle and rubber plate on the saddle to fix the U-shaped module tube, a plurality of strings for the side of the upper and lower support Reactor U-shaped modular tube construction apparatus characterized in that the lifting lugs are formed to be configured to move the upper and lower supports.
The method of claim 1, wherein the plurality of tie straps, one side of the U-shaped module tube, the inside of the casing inlet bottom weld connection of the coolant pump of the reactor, the other side of the U-shaped module tube, the steam generator Inside the welding joint of the outlet elbow, the tie straps are fixed to the welding grooves at intervals such as circumferential directions, respectively, so as to be restrained from shrinkage by welding or screwing, and after the external welding of the welding joint is completed, the U-shaped module Reactor U-shaped modular tube construction apparatus characterized in that it is removed from the welding connection between the tube, the lower end of the casing inlet of the coolant pump of the reactor, and the outlet tube elbow of the steam generator.
According to claim 1, wherein one side of the U-shaped module tube, the lower end of the casing inlet welding connection of the coolant pump of the reactor, the other side of the U-shaped module tube, the welding connection of the outlet pipe elbow of the steam generator Reactor U-shaped modular pipe construction device, characterized in that welding work is done and completed at the same time by using tie straps to suppress welding contraction of the narrow-gap GTAW, which is rotated and welded along the orbital track, respectively.
The construction method according to claim 4, wherein a tie strap that is similarly applied to a hot leg and a cold leg that does not use a U-shaped module tube and is suppressed by welding shrinkage.
The inner surface of the connecting pipe to prevent welding shrinkage in the welding of reconnecting the steam generator after cutting 2, 3, and 4 cuts in the 2-loop, 3-loop, and 4-loop pressurized water reactor steam generator replacement projects. Construction method using tie straps.