JP5159698B2 - Shroud head temporary placement device and method of installing the same - Google Patents

Description

  The present invention relates to a shroud head temporary placement device for temporarily placing a shroud head in a DS pool during inspection or the like in a nuclear reactor, and a method for installing the same.

At the time of periodic inspection of the boiling water nuclear power plant, the shroud head is removed from the core shroud of the reactor pressure vessel (RPV), and this shroud head is temporarily placed on the floor in the DS pool. The temporarily placed shroud head is fixed to the top of the core shroud by a shroud head bolt and a seismic pin.

  When installing the shroud head, make sure that the shroud head bolt and seismic pin hole attached to the shroud head do not interfere with the shroud head bolt lug and seismic pin attached to the core shroud. Is installed. The guide pin is engaged with a guide pin bracket attached to the core shroud, so that the shroud head can be positioned.

  Further, when the shroud head is attached to or removed from the core shroud, the bifurcated portion of the guide pin bracket of the shroud head is extended from the opening of the reactor pressure vessel to the guide rod attached to the core shroud upper ring. This guides the shroud head so that it does not interfere with the inner wall of the reactor pressure vessel.

JP 2007-102111 A

  During periodic inspection, the shroud head is removed from the core shroud and moved to the DS pool for fuel replacement or the like. The lower end of the four suspension rods provided to move the shroud head has the role of a leg, and the lower surface of the leg is temporarily placed on the floor surface in the DS pool so that the shroud head is self-supporting. ing.

  During plant operation, the shroud head is fixed to the upper part of the core shroud in the reactor pressure vessel with shroud head bolts and earthquake-resistant pins, so the shroud head can move or fall even if an earthquake occurs during operation. There is little nature.

  On the other hand, during the periodic inspection, the shroud head is temporarily placed in the DS pool so that it is self-supporting with four suspension rods. For this reason, when an earthquake or the like occurs, the shroud head is shaken by the acceleration of the earthquake and the sloshing of the water in the DS pool, etc., and at the same time, the suspension rod receives a pressing force against the floor surface, so that a frictional force acts. As a result, the suspension bar is deformed into an arcuate shape, bent in the radial direction, and exerts a deformation force. If the horizontal excitation direction is reversed, the suspension bar may be damaged.

  When the amount of deformation of the suspension rod increases, the suspension rod interferes with the core shroud when the shroud head is attached to the core shroud. Moreover, the guide pin attached to the shroud head is also deformed, and it becomes difficult to re-install the shroud head in the furnace.

  A lining portion exists on the floor surface of the DS pool. However, in the case of a large earthquake, it is also assumed that the lining is damaged by the movement or the fall of the shroud head. In particular, the water in the DS pool is under dose, and preventing damage to the lining is paramount.

  The present invention has been made in view of such circumstances, and even when a large earthquake or the like occurs in a state where the shroud head is temporarily placed in the DS pool, the shroud head can be prevented from moving or falling. To provide a shroud head temporary placement device and a method for installing the same that can prevent the deformation and damage of the shroud head and the suspension rod, etc., and also prevent leakage of water contained in the DS pool. With the goal.

In order to achieve the above object, according to the present invention, there is provided a shroud head temporary placing device for temporarily placing and supporting a shroud head taken out from a reactor pressure vessel in a DS pool, which is provided at the bottom of the DS pool. a frame shroud head for mounting the shroud head, and a mechanical fixing means for fixing the shroud head to the frame for this shroud head, along the mounting member prior Symbol shroud head in the circumferential direction, before the listen block a plurality of seismic pins out collision upward respectively from the upper end portion is provided, so these seismic pins engaged with the seismic pin hole formed in the shroud head rim body of the shroud head, horizontal of the shroud head A shroud head temporary placement device characterized in that a load in a direction is received by the earthquake-resistant pin.

According to the present invention, there is also provided a shroud head temporary placement method in which the shroud head taken out from the reactor pressure vessel is temporarily placed in the DS pool, the shroud head mount provided on the bottom of the DS pool. A step of mounting the shroud head; a step of fixing the mounted shroud head to the shroud head mount by mechanical fixing means; and vibration suppression means for supporting the shroud head mount from the side to suppress seismic vibration. The method for installing the temporary shroud head device is provided.

According to the present invention, even if a large earthquake occurs when the shroud head is temporarily placed in the DS pool , the shroud head is mechanically supported by the shroud head pedestal to suppress the seismic vibration. It is possible to prevent the head from moving or falling.

  In addition, the shroud head can be prevented from moving or toppling over to prevent damage to the shroud head, and without damaging the lining in the DS pool, preventing leakage of water under the dose in the DS pool. It is also possible.

1 is a layout diagram of a shroud head temporary placement device according to a first embodiment of the present invention. FIG. Explanatory drawing which shows the state which mounted the shroud head in the shroud head temporary placement apparatus shown in FIG. The side view which shows the shroud head temporary placement apparatus of the said 1st Embodiment. AA sectional drawing of FIG. The side view which shows the structure of the shroud head applied in the said 1st Embodiment. BB sectional drawing of FIG. The enlarged view which shows the state which made the shroud head stand by the said 1st Embodiment supported the shroud head. FIG. 8 is an enlarged view showing a state where the shroud head is further lowered from the state of FIG. 7. The block diagram which shows the state which assembled the base for shroud heads and the shroud head. The top view which shows the arrangement configuration of the shroud head mount by the said 1st Embodiment. The side view which shows the shroud head mount by 2nd Embodiment of this invention. The top view of FIG. The side view which shows 3rd Embodiment of this invention. FIG. 14 is a plan view of FIG. 13. The side view which shows the shroud head temporary placement apparatus by 4th Embodiment of this invention. The top view which shows the shroud head temporary placement apparatus by 5th Embodiment of this invention. The top view which shows the shroud head temporary placement apparatus by 6th Embodiment of this invention. The top view which shows the shroud head temporary placement apparatus by 7th Embodiment of this invention.

  Embodiments of a temporary shroud head placement apparatus and a temporary placement method according to the present invention will be described below with reference to the drawings.

First Embodiment (FIGS. 1 to 10)
FIG. 1 is an overall view showing an overall configuration and an installation position of a shroud head temporary placement device according to a first embodiment of the present invention.

  As shown in FIG. 1, a reactor well a, a DS pool b, and an equipment temporary storage pool (not shown) are provided in the reactor building, and a reactor pressure vessel c is installed in the reactor well a. Yes. At the time of the reactor inspection, the reactor well a and the DS pool b are brought into communication. The upper surface of the bottom e of the DS pool b is a horizontal plane.

  In this state, the steam dryer d removed from the reactor pressure vessel c is temporarily placed on the bottom e of the DS pool b, and the shroud of this embodiment is placed at the position of the DS pool b on the reactor pressure vessel c side. A shroud head mount 1 which is a main member of the head temporary placement device is fixedly installed by welding or the like.

  FIG. 1 shows a state in which the shroud head 2, the steam separator 3, and the core shroud 4 are installed in the reactor pressure vessel c.

  FIG. 2 shows a state in which the shroud head 2 and the steam / water separator 3 are taken out from the reactor pressure vessel c, and the shroud head 2 and the steam / water separator 3 are mounted on the shroud head mount 1.

  When the reactor is inspected, the interior of the DS pool b is filled with water, the steam dryer d is removed from the reactor pressure vessel c, and the steam dryer d is installed on the bottom e of the DS pool b. Temporarily placed on the gantry 1. The upper end of the temporarily placed shroud head pedestal 1 is set to a height h that is submerged in the reactor water by 1 m or more in consideration of the exposure dose on the operation floor.

  3 is an enlarged plan view showing the shroud head mount 1, and FIG. 4 is a cross-sectional view (vertical cross-sectional view) taken along line AA of FIG.

  As shown in FIGS. 3 and 4, the shroud head pedestal 1 includes, for example, a rectangular flat substrate 5 and a vertical ring-shaped support plate 6 which is welded to the upper surface of the substrate 5 and rises integrally. The substrate 5 and the ring-shaped support plate 6 are configured such that their center points coincide with each other.

  At the upper end of the ring-shaped support plate 6, a plurality of seismic pins 7 are projected upward at a constant height with a constant interval in the circumferential direction. These seismic pins 7 are erected at the center in the plate width direction of the horizontal upper end surface of the ring-shaped support plate 6, and the upper end surface of the ring-shaped support plate 6 is a horizontal plane.

  The seismic pins 7 are respectively fitted and inserted into holes, which will be described later, formed in the lower end portion of the shroud head 2 and have a function of preventing seismic vibration, particularly roll, of the shroud head 2. In addition, the diameter of the earthquake-resistant pin 7 is set to be sufficiently smaller than the plate width of the ring-shaped support plate 6.

  Further, on the outer peripheral side of the upper end portion of the ring-shaped support plate 6, as a structural part for defining the support position and posture of the shroud head 2 at regular intervals along the radial direction of the ring-shaped support plate 6, A pair of gantry brackets 8 and 8 are provided. These mount brackets 8, 8 are configured to protrude horizontally in opposite directions to the radially outer surface side of the ring-shaped support plate 6.

  Furthermore, guide rods 9 are provided at the projecting direction front ends of the gantry brackets 8 and 8 to serve as lifting guides when the shroud head 2 is installed. The pair of guide rods 9 and 9 has a high height projecting upward from the guide pin 11.

  The guide rods 9, 9 are arranged symmetrically with respect to the center of the ring-shaped support plate 6 and are erected vertically upward. The heights of the guide rods 9 and 9 are substantially the same, but are different from each other, and are configured so that the engaging operation with the guide rods 9 and 9 during the elevation is different. The shroud head 2 may be moved up and down smoothly.

  Guide pin holes 10 (10a, 10b) extending in the vertical direction are respectively drilled in the base end side of each of the gantry brackets 8, 8 protruding horizontally, that is, on the ring-shaped support plate 6 side. Guide pins 11 (shown in FIGS. 5 to 7) provided in the peripheral part of the steam separator 3 are inserted into the guide pin holes 10 a and 10 b, respectively.

  Further, on the outer peripheral side of the upper end edge of the ring-shaped support plate 6 of the shroud head pedestal 1, a plurality of shroud head bolt lugs 12 made of a pair of opposed pieces along the circumferential direction of the ring-shaped support plate 6 are provided. The ring-shaped support plate 6 protrudes at a constant interval in the circumferential direction. These shroud head bolt lugs 12... Have shroud head bolts 13 (details will be described later with reference to FIGS. 7 to 9) provided on the shroud head 2, and a pair of facing pieces of the shroud head bolt lugs 12. They are locked in a sandwiched state.

  When the shroud head pedestal 1 is composed of only the ring-shaped portion of the ring-shaped support plate 6, the ring-shaped portion of the ring-shaped support plate 6 can be deformed when a horizontal load is applied. There is sex. When the ring-shaped portion of the ring-shaped support plate 6 is deformed, the shroud head bolt 13 and the earthquake-resistant pin 7 cannot be positioned even if the guide pin 11 is inserted into the guide pin hole 10.

  For this reason, in this embodiment, the reinforcing plate 14 for struts and the substrate 5 are arranged in a radial arrangement from the position of each guide pin 11 at the lower end of the ring portion of the ring-shaped support plate 6 toward the center of the ring-shaped support plate 6. The protrusions are provided at the same height, and the ends of the reinforcing plates 14 are connected to the center support plate 16 provided at the center position of the ring portion, respectively, so as to have a deformation preventing function.

  Next, an assembly configuration of the shroud head mount 1 and the shroud head 2 will be described with reference to FIGS.

  FIG. 5 is a plan view showing the configuration of the shroud head 2, and FIG. 6 is a cross-sectional view (vertical cross-sectional view) taken along the line BB of FIG.

  As shown in FIGS. 5 and 6, the shroud head 2 includes a dome-shaped ring portion 2a and a steam / water separator 3 mounted on the ring portion 2a, and is fixed to the periphery of the lower end portion of the ring portion 2a. A width flange 2b projects horizontally. The ring portion 2a and the flange portion 2b are connected to each other by a short cylindrical rim body 17 made of an upright wall having a constant height.

  A pair of guide pin brackets 18, 18 for receiving the guide pin 11 are provided on the outer peripheral side of the lower end portion of the rim body 17 so as to protrude horizontally with respect to each other. 4 is formed in the lower end surface of the rim body 17 for connecting the earthquake-resistant pins 7 shown in FIG. 4 in an inserted state. These seismic pin holes 19 are opened at the lower end surface of the rim body 17 so that the seismic pins 7 shown in FIG. 4 can be inserted.

  FIG. 7 is an operation explanatory view showing a state in which the shroud head 2 is suspended from the upper side on the shroud head mount 1 and both of them are assembled.

As shown in FIG. 7, first, the shroud head 2 is gradually suspended from above the fixedly arranged shroud head mount 1. In this case, the guide pin bracket 18 of the suspended shroud head 2 is aligned so as to coincide with the upper position of the guide rod 9 erected vertically from the shroud head mount 1. Simultaneously with this operation, the head bolt 13 of the shroud head 2 and the shroud head bolt lug 12 of the shroud head mount 1 are aligned.

FIG. 8 is an enlarged view showing a state where the shroud head 2 is further lowered from the state of FIG. FIG. 8 shows a state in which the bifurcated guide pin bracket 18 is engaged with the outer surfaces on both sides of the guide rod 9 and the guide pin 11 is inserted into the guide pin hole 10 of the gantry bracket 8.

In this case, the seismic pin hole 19 of the shroud head 2 faces the seismic pin 7 of the shroud head mount 1 in the vertical direction. Therefore, the shroud head 2 can be mounted on the upper surface of the shroud head mount 1 by further lowering the shroud head 2. At this time, the guide pin 11 passes through the guide pin hole 10 and protrudes downward, and at the same time, the earthquake-resistant pin 7 is inserted into the earthquake-resistant pin hole 19. Both the locking state of the guide pin 11 and the guide pin hole 10 and the locking state by inserting the earthquake-resistant pin 7 into the earthquake-resistant pin hole 19 are over the entire circumferential direction of the shroud head pedestal 1 and the shroud head 2. As a result, when the shroud head cradle 1 and the shroud head 2 are subjected to seismic vibration, particularly when they are subjected to roll vibration, the shroud head cradle 1 and the shroud head 2 are displaced. There is no.

In FIG. 8, the assembly configuration of the shroud head 2 and the guide pin 11 and the assembly configuration of the gantry bracket 8 and the guide rod 9 are shown in detail. As shown in FIG. 8, the guide rod 9 penetrates through the guide rod mounting hole 21 formed of a circular through hole formed on the outer peripheral side of the gantry bracket 8 to the lower surface of the gantry bracket 8, It is fixed by welding or the like. With this configuration, the guide rod 9 is firmly attached to the gantry bracket 8 and can be kept upright without fear of tilting or the like.

Further, the guide pin 11 has a stepped pin structure having a small diameter sequentially from the lower end side to the upper end side. The small upper end portion 11 a of the guide pin 11 is inserted into the guide pin hole 18 b of the guide pin bracket 18 and the sleeve 22. The upper end of the guide pin 11 protrudes above the guide pin bracket 18.

On the other hand, the lower end 22a of the sleeve 22 is formed in a skirt shape, that the guide pin 11 to the lower end of this sleeves 22 abuts, is a configuration in which omission of the upward guide pin 11 is prevented .

  Further, a nut 24 is screwed into a screw portion 23 formed on the outer peripheral surface of the sleeve 22, and the nut 24 is pressed against the upper surface of the guide pin bracket 18, whereby the guide pin 11 is guided through the sleeve 22. The bracket 18 is sandwiched from above and below. As a result, the guide pin 11 is firmly fixed to the guide pin bracket 18 and is configured to maintain a constant shape without causing lateral vibration or the like.

The lower end portion of the guide pin 11 is configured to be surely insertable and detachable in the vertical direction while being in sliding contact with the inner peripheral surface of the guide pin hole 10 of the gantry bracket 8.

  Further, FIG. 8 shows a seismic pin 7 protruding from the upper end surface of the shroud head mount 1 and a seismic pin hole 19 on the lower surface of the shroud head 2 into which the seismic pin 7 is inserted. The seismic pins 7 and the seismic pin holes 19 are formed with high accuracy, and are fitted by lowering the shroud head 2. As shown in FIG. 3 and FIG. 4, a large number of the earthquake-resistant pins 7 are provided, and the fixed state can be firmly held against vibration during an earthquake or the like.

The clearance between the outer peripheral surface of the guide pin 11 and the guide pin hole 10 of the gantry bracket 8 is stricter than the clearance between the shroud head bolt 13 and the shroud head bolt lug 12 and the clearance between the earthquake resistant pin 7 and the earthquake resistant pin hole 19. Since accuracy is required, the clearance between the shroud head bolt 13 and the earthquake-resistant pin 7 can be maintained when the guide pin 11 engages with the guide pin hole 10. For this reason, the shroud head mount 1 is provided with a mount bracket 8 similar to the core shroud 4 and uses a guide pin hole 10.

  FIG. 9 is a configuration diagram showing a state in which the shroud head mount 1 and the shroud head 2 are assembled.

  As shown in FIG. 9, in the configuration in which the shroud head mount 1 and the shroud head 2 are assembled, the guide pin 11 and the shroud head bolt 13 of the shroud head 2 protrude downward from the lower surface of the rim body 17. It becomes a state. Therefore, the height of the ring-shaped support plate 6 that is the ring portion of the shroud head mount 1 on which the shroud head 2 is seated so that the lower ends of the guide pins 11 and the shroud head bolts 13 do not interfere with the floor surface of the DS pool b. Is set.

  On the other hand, the height of the ring-shaped support plate 6 that is the ring portion of the shroud head pedestal 1 is as described above after the shroud head 2 is installed on the shroud head pedestal 1 in consideration of the radiation dose on the operation floor. (Refer FIG. 2), It is set as the structure restrict | limited to the height h at which the upper end of the steam-water separator 3 attached to the shroud head 2 is submerged 1 m or more.

  Further, when the shroud head 2 is lowered in the DS pool b and installed on the shroud head pedestal 1, the shroud head bolt 13 and the seismic pin hole 19 of the shroud head 2 are connected to the shroud of the shroud head pedestal 1. It is necessary not to interfere with the head bolt lug 12 and the earthquake-resistant pin 7.

  Therefore, in the present embodiment, in order to position the shroud head 2, the guide function is obtained by the guide pins 11 attached to the shroud head 2.

In this case, the bifurcated guide pin bracket 18 of the shroud head 2 is moved down along the guide rod 9 attached to the shroud head mount 1. As a result, as shown in FIG. 8, the guide pins 11 are engaged with each other without interfering with the gantry bracket 8 of the shroud head gantry 1, and the guide pins 11 are inserted.

Further, as described above, the clearance between the guide pin 11 and the guide pin hole 10 of the gantry bracket 8 is the clearance between the shroud head bolt 13 and the shroud head bolt lug 12 and the clearance between the earthquake resistant pin 7 and the earthquake resistant pin hole 19. By requiring stricter accuracy, the clearance between the shroud head bolt 13 and the seismic pin 7 can be maintained when the guide pin 11 is engaged with the guide pin hole 10 . That is, a gantry bracket 8 similar to the core shroud 4 is attached to the shroud head gantry 1 and the guide pin hole 10 is used.

Thus, at the time of attachment, the shroud head mount 1 can be installed in the DS pool b, and the shroud head 2 can be mounted on the shroud head mount 1 and mechanically fixed. The shroud head 2 and the shroud head mount 1 can receive a vertical load by a plurality of shroud head bolts 13 and a horizontal load by a plurality of seismic pins 7.

  The centering of the shroud head 2 and the core shroud 4 can be performed by the guide pin 11 attached to the shroud head 2 being engaged with the guide pin hole 10 of the bracket attached to the core shroud 4. Positioning is possible.

  Further, when the shroud head 2 is lowered in the reactor pressure vessel c, the guide pin 11 is engaged before the earthquake resistant pin 7 and the shroud head bolt 13, so that the shroud head bolt 13 and the earthquake resistant pin 7 are connected to the core shroud 4. The bracket and the shroud head bolt lug 12 are not interfered with.

  Even in the DS pool b, the shroud head pedestal 1 simulating a part of the upper shell of the core shroud 4 is installed in the DS in the same manner as the configuration in which the shroud head 2 and the core shroud 4 are fixed in the reactor pressure vessel c. It is installed in the pool b, and the shroud head 2 is fixed to the shroud head mount 1.

  As shown in FIGS. 3 and 4, the guide pin 11 of the shroud head 2 is inserted into the guide bracket hole 10 of the shroud head base 1 of the present embodiment without interfering with the guide pin hole 10. The two guide rods 9 are attached to the gantry bracket 8 of the shroud head gantry 1.

The height of the guide rod 9 is determined in consideration of the dimensions necessary for the tip of the guide pin 11 protruding downward from the guide pin bracket 18 to be inserted into the guide pin hole 10.

  Then, after the shroud head 2 is removed from the shroud head mount 1 and moved into the reactor pressure vessel c, the steam dryer d is moved into the reactor pressure vessel c.

  Accordingly, the height of the guide rod 9 is limited to a height at which the steam dryer d can move underwater when the steam dryer d is moved over the head of the guide rod 9 and moved into the reactor pressure vessel c. I will do it.

  FIG. 10 is a plan view for explaining the arrangement and installation method of the shroud head mount 1.

  During the periodic inspection, as shown in FIGS. 1 and 2, the steam dryer d and the shroud head 2 are removed from the core shroud 4 and moved to the DS pool b. In this case, the installation position of the shroud head mount 1 is set at the lower part of the place where the shroud head 2 is temporarily placed, and the shroud head 2 is installed at the upper part thereof.

  If an earthquake occurs when the shroud head base 1 is not fixed to the DS pool b and the shroud head 2 is installed on the shroud head base 1, the lining of the floor surface of the DS pool b is damaged and the floor of the DS pool b is damaged. Pool water may leak from the surface. Reinforce the lining to prevent damage and leakage.

  Further, by fixing the shroud head mount 1 on the side surface of the DS pool b with a steel material, for example, H-shaped steel 25, the shroud head mount 1 is prevented from moving in the DS pool b and damaging the DS pool b. is there.

  When the shroud head pedestal 1 is composed of only a ring, the ring portion of the ring-shaped support plate 6 may be deformed when a horizontal load is applied. When the ring portion of the ring-shaped support plate 6 is deformed, the shroud head bolt 13 and the earthquake-resistant pin 7 cannot be positioned even if the guide pin 11 is inserted into the guide pin hole 10. For this reason, in this embodiment, it is set as the structure which inserts the reinforcement board 14 for protrusions in the inner surface of the ring part of the ring-shaped support plate 6, and prevents a deformation | transformation of a ring part.

  According to the present embodiment, even when a large earthquake occurs when the shroud head 2 is temporarily placed in the DS pool, the shroud head base 1 is fixed to the side surface of the DS pool b with the H-shaped steel 25, so that the shroud It is possible to prevent the head 2 from moving or toppling over, preventing the shroud head 2 from being damaged, and preventing leakage of water under a dose in the DS pool b due to damage to the lining in the DS pool b. It becomes.

In this embodiment, the step of installing the shroud head temporary placement device includes the step of mounting the shroud head 2 on the shroud head mount 1 provided at the bottom of the DS pool b, and the mounting of the shroud head 2 mechanically. performing a step of fixing the fixing means depending on the shroud head gantry 1, and the step of the gantry 1 for the shroud head is supported laterally provided vibration suppression means you suppress seismic vibrations.

  By this step, the shroud head temporary placement device can be installed efficiently and reliably.

Second Embodiment (FIGS. 11 and 12)
FIG. 11 is a plan view of the gantry 1 according to the second embodiment of the present invention, and FIG. 12 is a side view of FIG.

  In the present embodiment, a case will be described in which the ring configuration of the shroud head pedestal 1 is configured to simulate the core shroud 4.

  As shown in FIGS. 11 and 12, in this embodiment, the ring configuration of the shroud head mount 1 is not a rim type but a configuration using H-shaped steel. That is, the ring structure is made of H-shaped steel in which a ring-shaped vertical frame portion is welded between a pair of upper and lower flat ring portions.

  Further, unlike the first embodiment, the shroud head pedestal 1 is not an integral type, but has a structure in which a plurality of divided bodies (for example, two bodies) are detachably connected in the circumferential direction. Are connected to each other by a fastener 31 such as a bolt or a nut to form a ring shape. In addition, it can replace with connection with a volt | bolt, a nut, etc., can also be connected by welding, and can also be comprised in a ring shape.

  Even in the present embodiment having such a configuration, as in the first embodiment, even when a large earthquake occurs when the shroud head 2 is temporarily placed in the DS pool b, the shroud head 2 can be moved or overturned. It is possible to prevent the shroud head 2 from being damaged, and it is possible to prevent leakage of water under a dose in the DS pool b due to lining damage in the DS pool b.

[Third Embodiment] (FIGS. 13 and 14)
FIG. 13 is a plan view of the shroud head mount 1 according to the third embodiment of the present invention, and FIG. 14 is a side view thereof.

The third embodiment is different from the above-described embodiment in that the shroud head mount 1 (1a to 1e) is provided only at a necessary portion when the earthquake-resistant pin 7 and the shroud head bolt lug 12 are attached.
That is, the shroud head 7 and the shroud head bolt lug 12 are attached to the portion to which the shroud head mount 1 is attached, and the shroud head 2 is fixed.

  With this configuration, even in the present embodiment, when a large earthquake occurs during temporary placement in the DS pool, the shroud head 2 is prevented from moving or toppling over to prevent damage to the shroud head 2 and lining in the DS pool. It is possible to prevent leakage of water under a dose in the DS pool due to damage or the like.

[Fourth Embodiment] (FIG. 15)
FIG. 15 is a side view (enlarged view) of the shroud head mount 1 according to the fourth embodiment of the present invention.

  This embodiment is different from the above embodiment in that the guide pin 11 is replaced with the shroud head bolt 13 and the earthquake-resistant pin 7, and the guide pin bracket 18 has a bifurcated portion 18 a and the guide rod 9. The configuration is such that the function of maintaining the clearance accuracy between the pin 7 and the shroud head bolt 13 is provided.

  In other words, a strict clearance similar to that of the guide pin 11 is ensured between the guide rod 9 and the bifurcated portion 18 a of the guide pin bracket 18. In the case of this configuration, since the function of the guide pin 11 is not used, a large guide pin hole 10 is secured.

  According to this configuration, since the guide pin hole 10 between the guide rod 9 and the bifurcated portion 18a of the guide pin bracket 18 is ensured, operations such as installation of the shroud head 2 can be easily performed.

  Further, even when a large earthquake occurs with the shroud head temporarily placed in the DS pool b, the shroud head 2 is prevented from moving or falling, and the DS pool is damaged due to damage to the shroud head and damage to the lining in the DS pool. It is possible to prevent leakage of water under the dose inside.

[Fifth Embodiment] (FIG. 16)
FIG. 16 is an enlarged vertical cross-sectional view showing the main configuration of the shroud head mount 1 according to the fifth embodiment of the present invention.

  The difference between this embodiment and the above embodiment is that the length dimensions (h1, h2) of the two guide rods 9a, 9b are different. That is, one guide rod 9a and the guide pin bracket 8 are engaged with each other, and the other guide rod 9b and the guide pin bracket 8 are engaged with each other while the shroud head 2 is lowered.

  According to the present embodiment, the lengths of the two guide rods 9a and 9b are made different so that one guide rod 9a (height h1) and the guide pin bracket 8 are engaged with each other, and the shroud head 2 is further configured. Since the other guide rod 9b (height h2) and the guide pin bracket 8 are combined with each other while lowering the guide rod, galling is generated between the guide pin bracket 8 of the shroud head 2 and the guide rods 9a and 9b. It can be prevented from occurring.

  Also in this embodiment, even when a large earthquake occurs with the shroud head 2 temporarily placed in the DS pool b, the shroud head 2 is prevented from moving and falling, and the shroud head 2 is damaged and the lining in the DS pool is used. It is possible to prevent leakage of water under a dose in the DS pool due to damage of the water.

[Sixth Embodiment] (FIG. 17)
FIG. 17 is a plan view showing a state in which the shroud head mount 1 according to the sixth embodiment of the present invention is installed in the DS pool b.

  In the second embodiment described above (FIG. 11), the shroud head mount 1 is fixed to the side surface of the DS pool b with H-shaped steel, so that the shroud head mount 1 moves in the DS pool b, thereby causing the DS pool b. It was set as the structure which prevents damage.

  In contrast, in this embodiment, the shroud head mount 1 is fixed to the floor surface of the DS pool b by welding or the like.

  However, if the shroud head mount 1 is directly welded to the floor surface of the DS pool b, the floor surface of the DS pool b may be damaged in the event of an earthquake. After the reinforcement of the lining, the shroud head mount 1 is welded.

  According to the present embodiment, the floor surface damage of the DS pool b can be prevented, and the shroud head 2 can be prevented when a large earthquake occurs during temporary placement of the shroud head 2 in the DS pool, as in the above embodiments. It is possible to prevent the water under the dose in the DS pool b from leaking due to damage to the shroud head 2 and damage to the lining in the DS pool b.

[Seventh Embodiment] (FIG. 18)
FIG. 18 is a plan view showing a configuration in which the shroud head mount 1 according to the seventh embodiment of the present invention is installed in the DS pool b.

  In the present embodiment, the shroud head mount 1 is not fixed to the floor surface of the DS pool b, and the shroud head mount 1 slides on the floor surface of the bottom e of the DS pool b when an earthquake occurs. It is as.

  That is, the lower end portion of the ring portion of the shroud head pedestal 1 is tapered so that the width gradually decreases toward the lower side of the ring portion. The structure is such that the platform 1 is prevented from being caught on the floor surface of the bottom e of the DS pool b.

  According to the present embodiment, when a large earthquake occurs while the shroud head 2 is temporarily placed in the DS pool, the shroud head 2 can be moved by sliding the shroud head mount 1 on the floor surface of the DS pool b. Movement and falling can be prevented, and leakage of water under a dose in the DS pool due to damage to the shroud head 2 and lining in the DS pool can be prevented.

  Further, according to this configuration, since the shroud head mount 1 is not fixed inside the DS pool b, it can be taken in and out of the DS pool b.

  When this configuration is applied, as a means for easily installing the shroud head mount 1 at the same position in the DS pool b at each periodic inspection, the position of the shroud head mount 1 can be changed by marking the shroud head mount 1. It is desirable to match.

  After the inspection is completed, the steam / water separator 3 is suspended from the mounting state on the shroud head mount 1 shown in FIG. 2 to be installed in the reactor pressure vessel c shown in FIG.

a reactor well b DS pool c reactor pressure vessel d steam dryer e DS pool bottom 1 shroud head mount 2 shroud head 2a ring 2b collar 3 steam separator 4 core shroud 5 substrate 6 ring-shaped support plate 7 Seismic pin 8 Base bracket 9 Guide rod 10 (10a, 10b) Guide pin hole 11 Guide pin 12 Shroud head bolt lug 13 Shroud head bolt 14 Reinforcement plate 16 Central support plate 17 Rim barrel 18 Guide pin bracket 18a Fork
18b Guide pin hole 19 Seismic pin hole 21 Guide rod mounting hole 22 Sleeve 23 Screw part 24 Nut 25 H-shaped steel

Claims (5)

A shroud head temporary placing device for temporarily placing and supporting a shroud head taken out from the reactor pressure vessel in the DS pool, the shroud head mount being provided at the bottom of the DS pool and mounting the shroud head; and a mechanical fixing means for fixing the shroud head to the shroud frame head, before SL in the frame shroud head along the circumferential direction, and out collision toward the front asked stand on end upward respectively A plurality of seismic pins are provided, and these seismic pins are engaged with seismic pin holes formed in the shroud head rim body of the shroud head, and the horizontal load of the shroud head is received by the seismic pins. A temporary placement device for a shroud head. A guide rod is provided on the shroud head pedestal, and the guide pin of the shroud head and the guide pin hole of the shroud head pedestal engage with the forked portion of the guide pin bracket of the shroud head. Item 10. A temporary placement device for a shroud head according to item 1 . Wherein the frame shroud head, temporary device fixed claim 1, wherein the shroud head by welding to the floor surface of the support or pool due to steel on the sides of the DS pool. It said shroud cradle head is temporary device of the shroud head of claim 1, wherein the upper end of the steam separator mounted to the shroud head is set to a height that is submerged or 1 m. A method of temporarily placing a shroud head in which a shroud head taken out from a reactor pressure vessel is temporarily placed in a DS pool, wherein the shroud head is mounted on a shroud head mount provided at the bottom of the DS pool. And a step of fixing the mounted shroud head to the shroud head pedestal by mechanical fixing means, and a step of providing vibration suppression means for supporting the shroud head pedestal from the side to suppress seismic vibration. A method for installing a shroud head temporary placement device, wherein:

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