JP6084580B2 - Measuring device mounting stand for spent fuel pool - Google Patents

Description

  Embodiments of the present invention relate to a measuring device mounting base for mounting a measuring device such as a water level meter and a thermometer in a spent fuel pool.

  As a result of the Great East Japan Earthquake, the Fukushima Daiichi Nuclear Power Station experienced an event of a drop in the level of the spent fuel pool. In order to monitor such an event of a water level drop, a heat thermo type water level temperature measuring device has been developed. This heat thermo-type water level temperature measuring device has a set of sensors in which a thermometer and a heater are combined. Specifically, this water level temperature measuring device determines the water level by comparing changes in the rate of temperature rise in water and in the air due to heating with a heater (see, for example, Patent Document 1).

  Since this water level temperature measuring device determines the presence or absence of water by each of a set of sensors, it is necessary to install a plurality of sensors at intervals in the depth direction of the spent fuel pool. Therefore, this water level temperature measuring device is formed in an elongated shape according to the water depth of the spent fuel pool (see, for example, Patent Document 2).

  Currently, this water level temperature measuring device is attached using embedded metal fittings installed in the spent fuel pool. The water level temperature measuring device is attached so as to satisfy the S class of the seismic class described in the nuclear power plant seismic design technical guidelines. Thereby, the water level can be measured even after the occurrence of the earthquake.

Japanese Patent Laid-Open No. 10-153681 JP 2013-104675 A

  As described above, the water level temperature measuring device is attached so as to satisfy the seismic class S described in the nuclear power plant seismic design technical guideline using the embedded metal fittings. If the seismic class S described in the nuclear power plant seismic design technical guideline cannot be satisfied using only the embedded metal fitting, it is necessary to install an additional support member.

  However, from the viewpoint of preventing leakage of water, there are restrictions such as that the mounting holes cannot be provided on the wall surface of the spent fuel pool, the wall surface of the spent fuel pool is not damaged, and foreign matter is not mixed into the spent fuel pool. is there. Therefore, it is impossible to install an additional mounting bracket. Accordingly, it is necessary to provide a mounting base to which the water level temperature measuring device can be attached by fixing only the operation floor floor surface without using the embedded bracket.

  Thus, the mounting base fixed only on the floor surface of the operation floor must satisfy the seismic class S class described in the nuclear power plant seismic design technical guidelines. At the same time, a water level temperature measurement device is installed in a narrow space between the wall of the spent fuel pool and the fuel rack, and the displacement is reduced so that the water level temperature measurement device does not collide with the fuel rack and the wall of the spent fuel pool due to an earthquake. There is a need to. Therefore, there is a problem that the displacement must be reduced by reducing the weight while securing the strength of the water level temperature measuring device.

  Therefore, an embodiment of the present invention has been made to solve the above-described problem, and does not use embedded metal fittings, can be used to improve the seismic performance of the measuring device and reduce the displacement due to the earthquake. An object of the present invention is to provide a fuel pool measuring device mounting base.

  In order to achieve the above object, the spent fuel pool measuring device mounting stand according to the present embodiment includes a base portion fixed to the operation floor and a rear end fixed to the base portion, and a tip is used. An attachment member extending along the depth direction of the wall surface of the fuel pool and having a measuring device attached thereto, wherein the attachment member is formed to be thin in stages toward the tip direction. To do.

  According to the present embodiment, the seismic performance of the measuring device can be improved and the displacement due to the earthquake can be reduced without using embedded metal fittings.

It is a side view which shows the measuring device mounting stand of the spent fuel pool of 1st Embodiment. It is a front view of FIG. It is an expanded sectional view by the III-III line of FIG. It is an expanded sectional view by the IV-IV line of FIG. It is an expanded sectional view by the VV line of FIG. It is a side view which shows the measuring device mounting stand of the spent fuel pool of 2nd Embodiment. FIG. 7 is a front view of FIG. 6. It is an expanded sectional view by the VIII-VIII line of FIG. It is an expanded sectional view by the IX-IX line of FIG. It is an expanded sectional view by the XX line of FIG. It is a side view which shows the measuring device mounting stand of the spent fuel pool of 3rd Embodiment. It is a front view of FIG. It is a side view which shows the measuring device mounting stand of the spent fuel pool of 4th Embodiment. FIG. 14 is a front view of FIG. 13. It is a side view which shows the measuring device mounting stand of the spent fuel pool of 5th Embodiment.

  Hereinafter, a water level temperature measuring device mounting base for a spent fuel pool according to the present embodiment will be described with reference to the drawings.

(First embodiment)
[Constitution]
FIG. 1 is a side view showing a measuring device mounting base for a spent fuel pool according to the first embodiment. FIG. 2 is a front view of FIG. FIG. 3 is an enlarged cross-sectional view taken along line III-III in FIG. 4 is an enlarged sectional view taken along line IV-IV in FIG. FIG. 5 is an enlarged sectional view taken along line VV in FIG.

  In the following embodiment, a case where a water level temperature measuring device 1 that measures the water level and temperature in the spent fuel pool is applied as a measuring device will be described.

  As shown in FIGS. 1 and 2, the spent fuel pool measuring device mounting base of the present embodiment includes a base portion 2 fixed to an operation floor floor 21 and a water level temperature measurement fixed to the base portion 2. A metal cylinder 3 as an attachment member to which the device 1 is attached, two shake preventing plates 4 fixed between both sides of the cylinder 3 and the base part 2, and the base part 2 And a terminal box 6 installed on the upper surface.

  The water level temperature measuring device 1 is a device that determines a water level by combining a thermometer and a heater, and comparing the temperature rise rates in water and in the air caused by heating the heater.

  As for the base part 2, the base main body 2a is supported by the two support legs 2b. A support plate 2c is fixed to the lower ends of these two support legs 2b. A plurality of reinforcing ribs 2d are fixed between the support plates 2c and the side surfaces of the support legs 2b to increase the rigidity of the support legs 2b. Each support plate 2 c is fixed to the operation floor floor 21 by a plurality of anchor bolts 5. The plurality of anchor bolts 5 are previously planted on the operation floor floor 21. Thereby, as for the base part 2, the base main body 2a is fixed to the operation floor floor surface 21 via the support plate 2c and the support leg 2b.

  A terminal box 6 is installed on the upper surface of the foundation main body 2 a of the foundation 2. The terminal box 6 connects the water level temperature measuring device 1 and a cable (not shown).

  The cylindrical body 3 has a rear end (upper end) fixed to the base body 2a of the base portion 2 by welding. On both sides of the rear end of the cylindrical body 3, a shake preventing plate 4 formed in a triangular flat plate shape is fixed by welding. These shake prevention plates 4 are fixed by welding to the lower surface of the base body 2a of the base portion 2 at the upper side. That is, the shake preventing plate 4 is perpendicular to the spent fuel pool wall surface 20 and is fixed vertically downward from the lower surface of the base body 2a.

  The cylindrical body 3 has a tip (lower end) extending along the depth direction of the spent fuel pool wall surface 20. The cylinder 3 is installed in parallel to the spent fuel pool wall surface 20 at a predetermined interval. The cylindrical body 3 has a water level temperature measuring device 1 inserted therein. The tip of the water level temperature measuring device 1 extends to substantially the same length as the tip of the cylinder 3. The cylindrical body 3 has a large number of triangular openings 31 formed at regular intervals along the length direction.

  As shown in FIGS. 3 to 5, the cylindrical body 3 is formed such that the upper part 3 a is thick, the lower part 3 c is thin, and the intermediate part 3 b is intermediate between thick and thin. That is, the cylindrical body 3 is formed to be thin in three stages toward the distal end direction. Between the upper part 3a and the intermediate part 3b of the cylinder 3, and between the intermediate part 3b and the lower part 3c are each fixed by welding.

[Operation]
Next, the operation of this embodiment will be described.

  The cylindrical body 3 to which the water level temperature measuring device 1 is attached has a tip extending along the depth direction of the spent fuel pool wall surface 20. Thereby, the water level temperature measuring apparatus 1 can be installed by fixing only the operation floor floor surface 21.

  Further, the base portion 2 is rotated about the water level temperature measuring device 1, particularly the operation floor floor surface 21, in the direction parallel to the support floor 2 c by the plurality of anchor bolts 5. Seismic strength against seismic motion can be secured.

  Further, the shake preventing plate 4 is fixed by welding between the both sides of the rear end of the cylinder 3 and the base body 2a, and is perpendicular to the spent fuel pool wall surface 20 and vertically from the lower surface of the base body 2a. It is fixed below. Thereby, the cylinder 3 can suppress the vibration to the spent fuel pool wall surface 20 due to the earthquake motion by the vibration preventing plate 4.

  Since the cylindrical body 3 is formed with a large number of openings 31 at regular intervals along the length direction, the entire cylindrical body 3 is reduced in weight, and the stress at the connecting portion between the base portion 2 and the cylindrical body 3 is reduced. Can be reduced.

  In addition, since the cylindrical body 3 is formed so as to be gradually thinner toward the distal direction, the weight moment at the distal end can be reduced and the displacement of the distal end can be suppressed while maintaining a predetermined strength. .

[Effect]
Thus, in this embodiment, the base part 2 is fixed to the operation floor floor 21, the rear end of the cylinder 3 to which the water temperature measuring device 1 is attached is fixed to the base part 2, and the cylinder 3 is The thickness is gradually reduced toward the direction.

  Therefore, according to this embodiment, it is possible to attach the water level temperature measuring apparatus 1 by fixing only the operation floor floor surface 21 without using the embedded metal fitting.

  As a result, the seismic performance can be improved and the displacement due to the earthquake can be reduced.

  In the present embodiment, the cylindrical body 3 is formed so as to be thinned in three steps toward the distal end direction. However, the thickness is not limited to this, and the cylindrical body 3 has a constant thickness in the length direction. You may form so that an outer diameter dimension may become small gradually in three steps toward the front-end | tip direction. Further, by combining these, the cylindrical body 3 may be formed so that the thickness decreases in three steps toward the distal end and the outer diameter decreases in three steps toward the distal end.

  Furthermore, in this embodiment, the shape of the opening 31 is formed in a triangle, but the shape is not limited to this, and may be formed in another polygon such as a lattice shape.

  In this embodiment, the shake preventing plates 4 are fixed to the both sides of the rear end of the cylinder 3 by welding. However, the present invention is not limited to this, and the shake preventing plates 4 may be fixed to one side of the rear end of the cylinder 3. Good.

(Second Embodiment)
FIG. 6 is a side view showing the spent fuel pool measuring device mounting base of the second embodiment. FIG. 7 is a front view of FIG. 8 is an enlarged cross-sectional view taken along line VIII-VIII in FIG. FIG. 9 is an enlarged sectional view taken along line IX-IX in FIG. FIG. 10 is an enlarged cross-sectional view taken along line XX in FIG.

  In addition, this embodiment is a modification of the first embodiment, and the same or corresponding parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  In this embodiment, instead of the cylindrical body 3 of the first embodiment, as shown in FIGS. 6 and 7, an assembly structure 7 as an attachment member is fixed to the base body 2 a of the base portion 2. The assembly structure 7 is constructed by assembling four flat cross-sectional L-shaped angles 17 so that the whole has a flat cross-sectional rectangle (in this embodiment, substantially square), and a bar-like brace 8 serving as a connecting member therebetween. It is fixed with. That is, the four angles 17 are fixed by a plurality of braces 8 that are alternately inclined in the length direction.

  The four angles 17 have their rear ends (upper ends) fixed to the base body 2 a of the base portion 2. These angles 17 have tips (lower ends) extending along the depth direction of the spent fuel pool wall surface 20. The assembly structure 7 is installed in parallel to the spent fuel pool wall surface 20 at a predetermined interval. The assembly structure 7 has the water level temperature measuring device 1 inserted therein.

  On both sides of the rear end of the assembly structure 7, runout prevention plates 4 each formed in a triangular flat plate shape are fixed by welding. These shake prevention plates 4 are fixed by welding to the lower surface of the base body 2a of the base portion 2 at the upper side. That is, the shake preventing plate 4 is perpendicular to the spent fuel pool wall surface 20 and is fixed vertically downward from the lower surface of the base body 2a.

  As shown in FIGS. 8 to 10, the angle 17 of the assembly structure 7 is formed such that the upper portion 17a is thick, the lower portion 17c is thin, and the intermediate portion 17b is intermediate between thick and thin. . That is, the assembly structure 7 is formed to be thin in three stages toward the distal direction. The upper portion 17a and the intermediate portion 17b of the angle 17 and the intermediate portion 17b and the lower portion 17c are fixed to each other by welding.

  Other configurations and operations are the same as those in the first embodiment, and thus description thereof is omitted.

  As described above, according to the present embodiment, the assembly structure 7 as an attachment member to which the water level temperature measuring device 1 is attached is assembled with the L-shaped angle 17 in a square plane, and the space between them is fixed by the brace 8. . This makes it possible to obtain the same operations and effects as in the first embodiment.

(Third embodiment)
FIG. 11 is a side view showing the spent fuel pool measuring device mounting base of the third embodiment. FIG. 12 is a front view of FIG.

  In addition, this embodiment is a modification of the first embodiment, and the same or corresponding parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  In this embodiment, instead of the cylindrical body 3 of the first embodiment, a plate 9 formed in a flat plate shape is used as shown in FIGS.

  The plate 9 has a rear end (upper end) fixed to the base body 2 a of the base portion 2. On both sides of the rear end of the plate 9, a shake preventing plate 4 formed in a triangular flat plate shape is fixed by welding. These shake prevention plates 4 are fixed by welding to the lower surface of the base body 2a of the base portion 2 at the upper side. That is, the shake preventing plate 4 is perpendicular to the spent fuel pool wall surface 20 and is fixed vertically downward from the lower surface of the base body 2a.

  The front end (lower end) of the plate 9 extends along the depth direction of the spent fuel pool wall surface 20. The plate 9 is installed in parallel to the spent fuel pool wall surface 20 at a predetermined interval. A water level temperature measuring device 1 is attached to the plate 9 by a mounting bracket 10.

  The plate 9 is formed such that the upper part 9a is thick, the lower part 9c is thin, and the intermediate part 9b is intermediate between thick and thin. That is, the plate 9 is formed to be thin in three stages toward the tip direction. The upper part 9a and the intermediate part 9b of the plate 9 and the intermediate part 9b and the lower part 9c are fixed to each other by welding.

  Other configurations and operations are the same as those in the first embodiment, and thus description thereof is omitted.

  As described above, according to the present embodiment, the plate 9 as an attachment member to which the water level temperature measuring device 1 is attached is fixed to the base portion 2. Thereby, in addition to the same operation and effect as the first embodiment, since the plate 9 is formed in a flat plate shape, an effect of facilitating manufacture is obtained.

(Fourth embodiment)
FIG. 13: is a side view which shows the measuring device mounting stand of the spent fuel pool of 4th Embodiment. FIG. 14 is a front view of FIG.

  In addition, this embodiment is a modification of the first embodiment, and the same or corresponding parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  In this embodiment, it replaces with the anchor bolt 5 for fixing the foundation part 2 of the said 1st Embodiment to the operation floor floor surface 21, and is fixed with the welding part 11, as shown in FIG.13 and FIG.14. Yes. The welded portion 11 is formed by welding the support plate 2c to an embedded metal fitting (not shown) embedded in the operation floor floor surface 21.

  Therefore, in this embodiment, by fixing the support plate 2c of the base portion 2 and an unillustrated embedded bracket embedded in the operation floor floor surface 21 with the welded portion 11, the anchor bolt 5 that has been implanted in advance is fixed. As compared with the first embodiment, the positioning is facilitated.

  As described above, according to the present embodiment, in addition to the effects of the first embodiment, the water level temperature measurement can be performed if a metal fitting such as an embedded metal fitting is fixed in advance even at a location where it cannot be fixed by the anchor bolt 5. The apparatus 1 can be installed.

(Fifth embodiment)
FIG. 15 is a side view showing the spent fuel pool measuring device mounting base of the fifth embodiment.

  In addition, this embodiment is a modification of the first embodiment, and the same or corresponding parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  In the present embodiment, as shown in FIG. 15, in addition to the configuration of the first embodiment, a plurality of cushioning materials 12 are attached to the spent fuel pool wall surface 20 side of the cylindrical body 3 to which the water level temperature measuring device 1 is attached. ing. These shock absorbing materials 12 are provided with a plurality of stainless steel coil springs 12a.

  Therefore, in the present embodiment, the plurality of shock absorbers 12 are attached to the spent fuel pool wall surface 20 side of the cylindrical body 3, so that even if the cylindrical body 3 is displaced due to earthquake motion, the spent fuel pool wall surface 20 is displaced. The amount of displacement can be absorbed. Therefore, the spent fuel pool wall surface 20 is not damaged by the cylinder 3.

  As described above, according to the present embodiment, in addition to the effects of the first embodiment, by attaching the buffer material 12 to the spent fuel pool wall surface 20 side of the cylindrical body 3, Damage can be prevented.

(Other embodiments)
Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, changes, and combinations can be made without departing from the scope of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

  For example, in each of the above embodiments, the cylindrical body 3, the assembly structure 7, and the plate 9 are formed so as to be thinned in three stages toward the distal end, but the thickness is reduced in other plural stages. You may form in.

  Moreover, although the said each embodiment demonstrated the example which formed the cylinder 3 and the assembly structure 7 in the flat cross section square shape, you may make it form circularly, for example, without being limited to this.

  Furthermore, in the said 1st-3rd embodiment, it can replace with the anchor bolt 5 and can apply the welding part 11 of 4th Embodiment. And in the said 1st-3rd embodiment, it is also possible to set it as the structure which combined 5th Embodiment.

  DESCRIPTION OF SYMBOLS 1 ... Water level temperature measuring device, 2 ... Base part, 2a ... Base main body, 2b ... Support leg, 2c ... Support plate, 2d ... Reinforcement rib, 3 ... Cylindrical body (attachment member), 3a ... Upper part, 3b ... Middle part, 3 ... lower part, 4 ... anti-vibration plate, 5 ... anchor bolt, 6 ... terminal box, 7 ... assembly structure (attachment member), 8 ... brace (connection member), 9 ... plate (attachment member), 9a ... upper part, 9b: Intermediate part, 9c ... Lower part, 10: Mounting bracket, 11 ... Welded part, 12 ... Buffer material, 12a ... Coil spring, 17 ... Angle, 17a ... Upper part, 17b ... Intermediate part, 17c ... Lower part, 20 ... Used Fuel pool wall, 21 ... Operation floor, 31 ... Opening

Claims (8)

A foundation fixed to the floor of the operation floor;
A rear end is fixed to the base portion, a front end extends along the depth direction of the spent fuel pool wall surface, and an attachment member to which a measuring device is attached,
The spent fuel pool measuring device mounting stand, wherein the mounting member is formed so as to gradually decrease in thickness toward the distal direction.   The spent fuel pool measuring device mounting stand according to claim 1, wherein the foundation is fixed by a plurality of anchor bolts planted on the floor of the operation floor.   The spent fuel pool measuring device mounting stand according to claim 1, wherein the foundation is fixed to the operation floor by welding.   The rear end of the mounting member is fixed to the base portion, and the rear end of the mounting member and the base portion are perpendicular to the spent fuel pool wall surface and prevent the swing from vertically downward from the base portion. The measuring device mounting base for a spent fuel pool according to claim 1, wherein the plate is fixed.   The spent fuel pool measuring device mounting according to any one of claims 1 to 4, wherein the mounting member is formed in a cylindrical shape, and a plurality of openings are formed in a length direction. Mount.   2. The mounting member according to claim 1, wherein the mounting member is formed in an assembly structure in which angles having a L-shaped cross section are assembled so that the whole is a rectangular cross section, and a space between them is fixed by a connecting member. The measuring device mounting stand of the spent fuel pool as described in any one of 4 above.   The spent fuel pool measuring device mounting stand according to any one of claims 1 to 4, wherein the mounting member is formed as a flat plate.   The spent fuel pool measuring device mounting stand according to any one of claims 1 to 7, wherein a buffer material is provided on the spent fuel pool wall surface side of the mounting member.

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