JP2008292164A - Control rod for nuclear reactor and method for manufacturing it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control rod for a nuclear reactor which requires no load supporting member between a sheath and a hafnium metal plate and avoids the problem of local stress on the sheath by using a blade consisting of a zircalloy material and a hafnium material for the control rod for the nuclear reactor and whose life is prolonged by enhancing the integrity and mechanical/physical strength of the control rod for the nuclear reactor to improve the economical efficiency in the operation of the nuclear reactor. <P>SOLUTION: The control rod 1A for the nuclear reactor consists of a tie rod 4A with a cruciform cross section to join a leading-end structural material 2 and a tail-end structural material 3 integrated with a handle and four blades 9 whose cross sections protrude cruciformly and radially from the tie rod 4A and whose outer shells have cross sections shaped deeply like the letter "U". The blades 9 consist of a clad metal which has a blade outer shell layer 15 made of the zircalloy material and a neutron absorbing element layer 16 made of the hafnium material. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a long-life reactor control rod used in a boiling water reactor and a method for producing the same.

  A conventional hafnium plate type control rod (hereinafter referred to as “reactor control rod”) 1 having hafnium as a neutron absorbing element applied to a boiling water reactor or the like will be described with reference to FIGS. To do.

  24 to 26 are diagrams showing an outline of a conventional nuclear reactor control rod. FIG. 24 is a partially cut perspective view of a conventional nuclear reactor control rod, and FIG. 25 is a cross-sectional view schematically showing one wing of four conventional wings having a cross-shaped cross section. FIG. 26 is a perspective view of a load support member that also serves as a gap retainer.

  As shown in FIG. 24, for example, a conventional nuclear reactor control rod 1 has a cross-shaped central structure material (hereinafter referred to as a “tie rod”) that joins a tip structure material 2 and a terminal structure material 3 integrated with a handle. 4), four wings 6 each having a U-shaped cross-section with a deep U-shaped cross section projecting radially from the tie rod 4 in a cross-sectional shape and a U-shaped section formed of hafnium or a hafnium alloy. It is comprised with a pair of plate-shaped object (henceforth a "hafnium metal plate") 7 accommodated facing in the sheath 5 of a letter-shaped cross section. The terminal structure member 3 is provided with a speed limiter 14.

  The nuclear reactor control rod 1 is inserted between a set of four reactor fuels to perform reactivity control, and is an important component for safely stopping the core in an emergency.

  Stainless steel is used for the sheath 5 constituting the outer shell of the wing 6 of the nuclear reactor control rod 1, and the opening of the U-shaped cross section is welded to the protruding portion of the tie rod 4. The sheath 5 is provided with a plurality of sheath holes 10 and water passage holes 11.

  As shown in FIG. 25, the hafnium metal plate 7 is supported in an opposed state by a plurality of load support members 8 on the inner surface of the sheath 5 constituting the outer shell of the wing 6.

  This load support member 8 also serves as a spacing spacer for the hafnium metal plate 7 accommodated in the sheath 5 so as to be opposed thereto. A water gap 13 (a gap through which cooling water flows when used in a nuclear reactor) is formed between the hafnium metal plates 7.

  As shown in FIG. 26, the load support member 8 has a frame-like shape. The thickness of the space holding portion 8a at the center of the load support member 8 functions as a spacer for holding the hafnium metal plate 7 at a space. On the other hand, the support shafts 8 b on both sides of the load support member 8 are fitted and welded to the sheath holes 10 of the sheath 5 to support the hafnium metal plate 7 and transmit the load of the hafnium metal plate 7 to the sheath 5. That is, the hafnium metal plate 7 is sandwiched between the interval holding portion 8 a of the load support member 8 and the sheath 5. For example, the hafnium metal plate 7 is held by the sheath 5 using four load support members 8.

  The conventional nuclear reactor control rod 1 configured as described above is a corrosion product accumulated in the gap between the sheath 5 and the hafnium metal plate 7, and thermal expansion and irradiation growth between the sheath 5 and the hafnium metal plate 7. As a margin for absorbing relative displacement due to the difference, a gap is provided between the load support member 8 and the hafnium metal plate 7 so as to allow proper sliding.

The stainless steel material used for the sheath 5 and the hafnium material used for the hafnium metal plate 7 have different thermal expansion coefficients by about three times. For example, stainless steel material is 17.8 × 10 ⁻⁶ / K, and hafnium material is 5.9 × 10 ⁻⁶ / K (“Reactor Material Handbook” published by Nikkan Kogyo Shimbun). For this purpose, the diameter of the mounting hole 7a of the hafnium metal plate 7 is made larger than the diameter of the support shaft 8 of the load support member 8, so that mutual interference due to differences in thermal expansion and radiation growth during reactor operation can be avoided. Is done.

  In addition to the static load due to the weight of the hafnium metal plate 7 transmitted from the load support member 8 when the reactor control rod 1 is stationary, the sheath 5 is inserted into and removed from the sheath 5 (movement). In this state, a dynamic load due to the weight and acceleration of the hafnium metal plate 7 transmitted from the load support member 8 is applied. This dynamic load is, for example, a difference in relative motion between the sheath 5 and the hafnium metal plate 7 at the start of driving and deceleration of the reactor control rod 1 during intermittent operation of the reactor or rapid driving of the reactor emergency stop. Acts on the basis of the impact force.

  Each of these loads tends to be considered to be transmitted to the sheath 5 via the support shaft 8b of the load support member 8 for each of the plurality of mounting holes 7a provided in the hafnium metal plate 7. However, there is a gap between the mounting hole 7a of the hafnium metal plate 7 and the support shaft 8b of the load support member 8 in consideration of the difference in thermal expansion, etc. This gap is the temperature distribution of the nuclear reactor control rod 1 and each member. Due to manufacturing tolerances and the like, it is difficult to be uniform in all the mounting holes 7a. That is, each load in an actual machine is transmitted to the sheath 5 via the support shaft 8b of one unspecified load support member 8, and the sheath 5 may bear an excessive load locally. In securing the soundness of the sheath 5, it is not preferable.

  That is, if the gap between the load support member 8 and the hafnium metal plate 7 is too small, the difference in thermal expansion cannot be absorbed. On the other hand, if this gap is too large, a load generated by an impact force due to acceleration in intermittent driving (especially starting or decelerating emergency insertion operation of a nuclear emergency stop) when the nuclear reactor control rod 1 is inserted into or extracted from the core will be generated. growing. Therefore, the design margins of the sheath 5, the hafnium metal plate 7, and the load support member 8 are in a narrow range due to these contradicting restrictions.

  If the worst conditions overlap due to an increase in sliding resistance due to corrosion products accumulated in the gap between the sheath 5 and the hafnium metal plate 7 and the effects of irradiation growth due to neutron irradiation, the predetermined sliding cannot be absorbed, and stainless steel There is a risk of cracking due to tensile stress acting on the plate.

That is, if the material of the sheath 5 constituting the wing 6 of the nuclear reactor control rod 1 and the hafnium metal plate 7 is a stainless material and a hafnium material having a large difference in thermal expansion coefficient, the life of the nuclear reactor control rod is extended. May interfere. (Patent Document 1)
Further, since the nuclear reactor control rod has a high neutron irradiation amount, there is a possibility of cracking due to irradiation embrittlement of the stainless steel material.

Therefore, the sheath 5 is made of a zircaloy material that has high corrosion resistance in the reactor water environment, little neutron absorption, small irradiation embrittlement compared to stainless steel, and a thermal expansion coefficient that is not significantly different from the thermal expansion coefficient of the hafnium material. Expected to be applied to materials. However, zircaloy material and hafnium material are active metals, and the reactor control rod 1 composed of these materials is subjected to a large heat input such as normal arc welding and a heat-affected zone is easily spread over a wide range. It is not easy to manufacture.
Japanese Patent Laid-Open No. 10-104382

  If the reactor control rod can be used for a long period of time, it will contribute to improving the economic efficiency of the reactor operation. Therefore, it is significant to extend the life of the reactor control rod. In order to extend the life of nuclear reactor control rods, it is necessary to increase the mechanical and physical strength of nuclear reactor control rods, which is a constraint on extending the lifetime compared to the nuclear lifetime in neutron absorption.

  In order to solve the above-described problem, in the present invention, a sheath and a hafnium metal plate are obtained by using a blade made of a clad material formed by integrally laminating a zircaloy material and a hafnium material for a wing of a control rod for a nuclear reactor. Without the need for a load support member between them, avoiding the problem of local stress applied to the sheath, improving the soundness and mechanical / physical strength of the nuclear reactor control rod, and extending the life of the atomic An object of the present invention is to provide a nuclear reactor control rod and a method for manufacturing the nuclear reactor control rod that improve the economics of reactor operation.

  Further, in the present invention, Zircaloy is formed by a friction stir welding (FSW) that can be joined without increasing the temperature of the joint at the time of joining or higher than the melting point, or a laser welding method that enables local low heat input welding. Provided is a method of manufacturing a control rod for a nuclear reactor having a blade made of a clad material formed by integrally laminating a material and a hafnium material in a wing.

  In order to solve the above-mentioned problems, in the present invention, a long blade having a U-shaped cross section is fixed to a central structural member to form a wing having a cross-shaped cross section. In the reactor control rod in which the tip structural material and the terminal structural material are respectively fixed to the insertion end side and the neutron absorbing element is provided in the blade, the blade includes a blade outer shell layer made of zircaloy material. There is provided a control rod for a nuclear reactor characterized in that a plate-like clad material having a neutron absorbing element layer made of a hafnium material is formed into a U shape having a deep cross section.

  In the present invention, a plate-like clad material is manufactured by press-contacting a hafnium material and a zircaloy material, and the clad material is formed into a long blade shape having a deep U-shaped cross section by bending. A control rod for a nuclear reactor comprising: a step; and a step of forming a U-shaped cross-sectional opening of the blade to a central structural member by a friction stir welding method to form a cross-shaped cross-shaped wing A manufacturing method is provided.

  According to the nuclear reactor control rod according to the present invention, a blade made of a clad material formed by integrally laminating a zircaloy material and a hafnium material is used for the wing of the nuclear reactor control rod, so that the sheath and the hafnium No need for a load support member between the metal plates, avoiding the problem of local stress applied to the sheath, and improving the soundness and mechanical / physical strength of the nuclear reactor control rod to extend the life In addition, it is possible to provide a control rod for a nuclear reactor that improves the economic efficiency of the nuclear reactor operation.

  Further, according to the method for manufacturing a control rod for a nuclear reactor according to the present invention, a friction stir welding method and a local low heat input welding capable of joining without increasing the temperature of the joint part at the time of joining above the melting point are possible. A control rod for a reactor having a blade made of a clad material formed by integrally laminating a zircaloy material and a hafnium material by a laser welding method can be manufactured.

  DESCRIPTION OF EMBODIMENTS Embodiments of a reactor control rod and a method for manufacturing a reactor control rod according to the present invention will be described with reference to the drawings.

[First Embodiment]
A first embodiment of a reactor control rod and a method for manufacturing a reactor control rod according to the present invention will be described with reference to FIGS.

  FIG. 1 is a partially cut perspective view showing a first embodiment of a control rod for a nuclear reactor according to the present invention.

  For example, as shown in FIG. 1, a nuclear reactor control rod 1A has a cruciform cross-section tie rod 4A that joins a tip structural member 2 and a terminal structural member 3 integrated with a handle, and a cross section from the tie rod 4A. The wing 6A has four blades 9 that protrude radially in a cross shape and whose outer shell portion has a deep U-shaped cross section. The terminal structure member 3 is provided with a speed limiter 14.

  FIG. 2 is a cross-sectional view schematically showing a control rod for a nuclear reactor according to the present invention.

  As shown in FIG. 2, this nuclear reactor control rod 1 </ b> A has a tie rod 4 </ b> A having a substantially cross-shaped cross section in the central structural member. The tip of this tie rod 4A is provided with a convex portion into which the opening of the blade 9 having a U-shaped cross section is fitted. The blade 9 is formed by forming a plate-like clad material having a blade outer shell layer 15 made of Zircaloy material and a neutron absorbing element layer 16 made of hafnium material into a U-shaped cross section. The formed blade 9 has a blade outer shell layer 15 on the outer surface and a neutron absorbing element layer 16 on the inner surface, and a gap 13 is formed between the opposing plate-like portions of the neutron absorbing layer 16 on the inner surface. The convex portion at the tip of the cross-shaped cross section of the tie rod 4A has a thickness substantially equal to the distance between the inner surfaces of the openings of the blade 9, and the cross-shaped portion of the cross section of the tie rod 4A is the convex portion provided at the tip and the blade 9 It has a thickness substantially equal to the total thickness of the plate-like portions facing the openings. The tie rod 4A and the blade 9 are brought into contact with each other at this fitting portion and fixed at the front end of the U-shaped cross section of the blade 9 to form a wing 6A.

  The nuclear reactor control rod 1 </ b> A configured as described above does not require the load support member 8 that holds the sheath 5 and the hafnium metal plate 7 of the conventional nuclear reactor control rod 1. Accordingly, the wing 6A requires a hole corresponding to the sheath hole 10 of the sheath 5 constituting the wing 6 of the reactor control rod 1 and the mounting hole 7a of the load support member 8 provided in the hafnium metal plate 7. do not do. Further, there is no gap provided between the sheath 5 constituting the wing 6 of the nuclear reactor control rod 1 and the hafnium metal plate 7.

  Since the wing 6A constituting the reactor control rod 1A of the present embodiment uses a blade 9 made of a clad material in which a zircaloy material and a hafnium material are integrated, the wing 6 of the conventional reactor control rod 1 is constituted. The load supporting member 8 for holding the hafnium metal plate 7 on the sheath 5 is not required.

There is almost no difference in the coefficient of thermal expansion between the zircaloy material and the hafnium material. For example, the zircaloy material is 6.5 × 10 ⁻⁶ / K, and the hafnium material is 5.9 × 10 ⁻⁶ / K. Between the sheath 5 constituting the wing 6 of the conventional nuclear reactor control rod 1 and the hafnium metal plate 7, a gap for absorbing relative displacement due to differences in thermal expansion and irradiation growth is provided. The control rod 1A does not require this gap. Therefore, the influence of the sliding resistance due to the corrosion products accumulated in the gap between the sheath 5 and the hafnium metal plate 7 in the conventional nuclear reactor control rod 1 can be eliminated.

  Further, since the blade 9 constituting the nuclear reactor control rod 1A of the present embodiment is fixed to the tie rod 4A, the blade outer shell layer 15 has a static load due to the weight of the neutron absorbing element layer 16 and the nuclear reactor control rod. The blade outer shell layer 15 functions as a coating for the neutron absorbing element layer 16 without having to maintain the weight of the neutron absorbing element layer 16 generated by the 1A insertion / extraction operation (motion state) and the dynamic load due to acceleration. Therefore, in ensuring the soundness of the blade outer shell layer 15, it is not necessary to consider the transmission of the load from the neutron absorbing element layer 16.

  Further, since the thermal expansion coefficient of the blade outer shell layer 15 is larger than that of the neutron absorbing element layer 16, the expansion of the blade outer shell layer 15 is restricted by the expansion of the neutron absorbing element layer 16 at the reactor operating temperature. A compressive stress acts on the blade outer shell layer 15. Therefore, the influence of the tensile stress acting on the sheath 5 in the conventional nuclear reactor control rod 1 can be eliminated.

  Furthermore, the hafnium metal plate 7 constituting the conventional nuclear reactor control rod 1 does not function as a strength member of the nuclear reactor control rod 1, but in the nuclear reactor control rod 1A, the blade outer shell layer 15 and the neutron absorbing element layer are used. Since the blade 9 made of a clad material integrally formed with 16 is fixed to the tie rod 4A, the neutron absorbing element layer 16 has a function of reinforcing the mechanical and physical strength of the reactor control rod 1A.

  In the case of the wing 6A of the nuclear reactor control rod 1A, the reactor control rod 1A as a whole can be constructed by configuring the thickness of the neutron absorbing element layer 16 made of hafnium material (specific gravity, about 13) having a large specific gravity as required. Is easily controlled within a predetermined weight range.

  FIGS. 3 to 7 are views for explaining an outline of a method of manufacturing the blade 9 and fixing the tie rod 4A to constitute the wing 6A in the method of manufacturing the nuclear reactor control rod 1A. FIG. 3 is a process diagram for explaining a method of manufacturing the blade 9 and fixing the tie rod 4A to form the wing 6A in the method of manufacturing the reactor control rod 1A. 4 and 5 are explanatory views of a method of manufacturing a flat clad material made of a zircaloy material and a hafnium material, which are the materials of the blade 9. FIG. 6 is an explanatory view of a method of manufacturing a U-shaped blade 9 from a flat clad material made of Zircaloy material and hafnium material. FIG. 7 is a view for explaining a method of constituting the wing 6A by fixing the blade 9 to the tie rod 4A.

  In FIG. 3, in step S <b> 1, a flat clad material made of the zircaloy material 18 and the hafnium material 19 is manufactured. The zircaloy material 18 and the hafnium material 19 are joined by cold pressure welding or hot pressure welding (FIG. 4) using a rolling mill 21 and explosion pressure welding (FIG. 5) using an explosive 22.

  For the zircaloy material 18, a zircaloy alloy such as zircaloy 2 (equivalent to ASTM Grade R60802) or zircaloy 4 (equivalent to ASTM Grade R60804) is used.

  In step S2, the plate-like clad material manufactured in step S1 is formed by bending to manufacture a blade 9 having a U-shaped cross section (FIG. 6). If the curvature of the substantially semicircular portion of the bottom of the U-shaped cross section of the blade 9 is small and cracking occurs due to bending, it can be avoided by hot forming.

  In step S3, the tie rod 4A, which is the central structural member of the nuclear reactor control rod 1A, and the blade 9 manufactured in step S2 are joined by a friction stir welding method to form a wing 6A (FIG. 7).

  This joining is performed by fitting the opening of the blade 9 having a U-shaped cross section to the convex portion provided at the tip of the cross-shaped cross section of the tie rod 4A, and used in the friction stir welding method in the vicinity of the tip of the opening. The rotary tool 23 is rotated around the substantially normal direction of the joint to form a tie rod / blade joint 25 and the blade 9 is fixed to the tie rod 4A.

  The pressing force of the rotary tool 23 used in the friction stir welding method is 500 to 1000 kgf, the rotation speed is 500 to 3000 rpm, the moving speed is 50 to 300 mm / min, the tip diameter of the probe of the rotary tool 23 is 2 to 5 mm, and the probe is pushed in The amount is obtained by subtracting 0 to 0.5 mm from the total thickness obtained by adding the thicknesses of the zircaloy material 18 and the hafnium material 19, for example, the total thickness obtained by adding the thicknesses of the zircaloy material 18 and the hafnium material 19 is 2. If it is 4 mm, the push-in amount is 1.9 to 2.4 mm. For example, the thickness of the zircaloy material 18 is 0.8 to 1.4 mm, and the thickness of the hafnium material 19 is 0.8 to 2.0 mm.

  In the friction stir welding method, the temperature at the time of joining the members to be joined does not reach the melting point, but it is desirable to supply a shielding gas between the zircaloy material 18 and the hafnium material 19 containing active metal. For example, when the tie rod 4A and the blade 9 are joined, an inert gas of about 20 to 100 liters / minute is supplied to both the front and back surfaces of the member to be joined. For example, argon gas or helium gas can be used as the shielding gas.

  According to the method for manufacturing the nuclear reactor control rod 1A of the present embodiment, the friction stir welding method capable of joining without increasing the temperature of the joined portion at the time of joining to the melting point or higher, from the zircaloy material 18 and the hafnium material 19 The reactor control rod 1A having the blade 9 configured in the wing 6A can be manufactured.

[Second Embodiment]
A second embodiment of a reactor control rod and a method for manufacturing a reactor control rod according to the present invention will be described with reference to FIGS.

  In this nuclear reactor control rod 1B, the same components as those in the nuclear reactor control rod 1A of the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 8 to FIG. 9 are diagrams for explaining an outline of a method of manufacturing the blade 9 and fixing the tie rod 4A to constitute the wing 6A in the manufacturing method of the reactor control rod 1B. FIG. 8 is a process diagram for explaining a method of manufacturing the blade 9 and fixing the tie rod 4A to form the wing 6A in the manufacturing method of the nuclear reactor control rod 1B. FIG. 9 is a view for explaining a method of forming the wing 6A by fixing the blade 9 to the tie rod 4A.

  In FIG. 8, in step S3A, the tie rod 4A, which is the central structural member of the nuclear reactor control rod 1B, and the blade 9 manufactured in step S2 are welded by laser welding to form a wing 6A (FIG. 9).

  This welding is performed by attaching the opening of the blade 9 having a U-shaped cross section to the tip of the tie rod 4A having a cross-shaped cross section to form a tie rod / blade weld 28 to fix the blade 9 to the tie rod 4A. Further, the opening of the blade 9 having a U-shaped cross section is fitted into a convex portion provided at the tip of the cross-shaped cross section of the tie rod 4A, and a tie rod / blade weld 28 is formed to attach the blade 9 to the tie rod 4A. It can also be fixed (not shown).

The laser output of the laser beam 27a of the laser welding apparatus 27 used for the laser welding method is 400 to 2000 W on average, and the welding speed is about 300 to 2000 m / min. Also, argon gas is supplied to the shield gas to prevent oxidation of the tie rod / blade weld 28. In addition, a zircaloy material and a hafnium material can be used suitably as a welding wire. As the laser transmitter, a laser oscillator such as a CO ₂ laser, a YAG laser, a semiconductor laser, or a fiber laser can be used. As the laser oscillation mode, continuous oscillation and pulse oscillation modes can be used.

  According to the method for manufacturing the nuclear reactor control rod 1B of the present embodiment, the amount of heat input during welding can be reduced, the heat input range can be narrowed, and there is no large welding heat input as in normal arc welding or the like. The heat affected zone does not reach a wide area. Further, if the welding line is made long when the blade 9 is welded to the tie rod 4A by a welding method with a large welding heat input, the tie rod 4A and the blade 9 are approximately 0. Although there is a risk of shrinking by about 1%, according to the method of manufacturing the control rod 1B for a reactor of the present embodiment, welding with low heat input is possible, and shrinkage of this entire length can be suppressed by about one digit.

[Third Embodiment]
A third embodiment of a reactor control rod and a method for manufacturing a reactor control rod according to the present invention will be described with reference to FIGS. 10 to 13.

  In this nuclear reactor control rod 1C, the same components as those in the nuclear reactor control rod 1A of the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 10 to FIG. 13 are diagrams for explaining an outline of a method for manufacturing the blade 9 and fixing the tie rod 4A to constitute the wing 6A among the methods for manufacturing the nuclear reactor control rod 1C. FIG. 10 is a process diagram for explaining a method of manufacturing the blade 9 and fixing the tie rod 4A to form the wing 6A in the method of manufacturing the reactor control rod 1C. FIG. 11 is a diagram illustrating the configuration of the blade 9 having a U-shaped cross section. FIG. 12 is an explanatory view of a method for manufacturing a component constituting the blade 9 having a U-shaped cross section from a flat clad material made of a zircaloy material and a hafnium material. FIG. 13 is a view for explaining a method of manufacturing the blade 9 from the components constituting the blade 9 having a U-shaped cross section.

  When a blade is manufactured by bending from a clad material in which a zircaloy material 18 and a hafnium material 19 are integrally formed, if the curvature of the bottom of the U-shaped cross section of the blade 9 is smaller than the minimum bending radius in the bending, the blade 9 There is a risk that it may be difficult to perform integral molding.

  Therefore, in FIG. 10, in step S <b> 2 </ b> A, a part obtained by dividing the blade 9 is manufactured, and the part is welded by a laser welding method to manufacture the blade 9.

  In step S2a, the plate-like clad material manufactured in step S1 is formed by bending within a minimum bending radius, and formed into a blade component that is a part of the blade 9 having a U-shaped cross section.

  In step S2b, the blade 9 is manufactured by welding a plurality of blade components formed in part of the blade 9 in step S2a by a laser welding method.

  In this embodiment, for example, as shown in FIGS. 11 and 12, a substantially semicircular portion 9a at the bottom of the U-shaped cross section of the blade 9 is formed at one end of a pair of plate-like portions 9b opposed to the blade 9 by a substantially ¼ arc 9c. The blade parts 30 are formed by bending each of the parts. Next, the pair of plate-like portions 9b facing each other of the blade 9 are welded by a laser welding method with the tip portions of the substantially arcs 9c (tip portions of the blade component 30) being brought into contact with each other to produce the blade 9 (FIG. 13). The welding conditions by the laser welding method depend on the welding conditions of the second embodiment.

  In addition, the division | segmentation method of the substantially semicircle part 9a of the U-shaped cross-section bottom part of the braid | blade 9 is not restricted to the substantially 1/4 circular arc 9c, It can divide | segment into two or more parts.

  According to the method for manufacturing the nuclear reactor control rod 1C of the present embodiment, the curvature of the bottom of the U-shaped cross section of the blade 9 constituting the nuclear reactor control rod 1C is formed integrally with the zircaloy material 18 and the hafnium material 19. When the bending radius of the clad material is smaller than the minimum bending radius, a part obtained by dividing the blade 9 is manufactured, and this part is welded by a laser welding method to constitute the blade 9 and the control rod 1C for the reactor is installed. Can be manufactured.

[Fourth Embodiment]
A fourth embodiment of a reactor control rod and a method for manufacturing a reactor control rod according to the present invention will be described with reference to FIGS. 14 to 16.

  In this nuclear reactor control rod 1D, the same components as those in the nuclear reactor control rod 1A of the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  The nuclear reactor control rod 1D includes, for example, a tie rod 4A having a cross-shaped cross-section that joins the distal end structural member 2 and the end structural member 3 integrated with a handle, and a transverse cross-section protrudes radially from the tie rod 4A into a cross-shape. The outer shell portion is composed of a wing 6B having four blades 9A having a deep U-shaped cross section.

  FIG. 14 is a cross-sectional view schematically showing a control rod for a nuclear reactor according to the present invention.

  As shown in FIG. 14, this nuclear reactor control rod 1 </ b> D has a tie rod 4 </ b> A having a substantially cross-shaped cross section in the central structural member. The tip of the cross-shaped cross section of the tie rod 4A is provided with a convex portion into which the opening of the blade 9A having a U-shaped cross section is fitted. This blade 9A is configured by forming a plate-like clad material having a blade outer shell layer 15 made of Zircaloy material and a neutron absorbing element layer 16 made of hafnium material into a U-shaped cross section. The formed blade 9 </ b> A has a blade outer shell layer 15 on the outer surface and a neutron absorbing element layer 16 on the inner surface, and a gap 13 is formed between opposing plate-like portions of the neutron absorbing layer 16 on the inner surface. The convex portion at the tip of the cross-shaped cross section of the tie rod 4A has a thickness substantially equal to the distance between the inner surfaces of the openings of the blade 9A, and the cross-shaped portion of the cross section of the tie rod 4A is the convex portion provided at the tip and the blade 9A. It has a thickness substantially equal to the total thickness of the plate-like portions facing the openings. The tie rod 4A and the blade 9A are brought into contact with each other at this fitting portion and fixed at the tip of the opening of the U-shaped cross section of the blade 9A to constitute the wing 6B.

  The nuclear reactor control rod 1 </ b> D configured as described above does not require the load support member 8 that holds the sheath 5 and the hafnium metal plate 7 of the conventional nuclear reactor control rod 1. Accordingly, the wing 6B requires a hole corresponding to the sheath hole 10 of the sheath 5 constituting the wing 6 of the nuclear reactor control rod 1 and the mounting hole 7a of the load support member 8 provided in the hafnium metal plate 7. do not do. Further, there is no gap provided between the sheath 5 constituting the wing 6 of the nuclear reactor control rod 1 and the hafnium metal plate 7.

  FIGS. 15 to 16 are diagrams for explaining an outline of a method of manufacturing the blade 9A and fixing the tie rod 4A to constitute the wing 6B among the manufacturing method of the nuclear reactor control rod 1D. FIG. 15 is a process diagram for explaining a method of manufacturing the blade 9A and fixing the tie rod 4A to form the wing 6B in the manufacturing method of the nuclear reactor control rod 1D. FIG. 16 is a view for explaining a method of manufacturing the blade 9A from the components constituting the blade 9A having a U-shaped cross section.

  When a blade is manufactured by bending from a clad material in which a zircaloy material 18 and a hafnium material 19 are integrally formed, if the curvature of the bottom of the U-shaped cross section of the blade 9 is smaller than the minimum bending radius in the bending, the blade 9 There is a risk that it may be difficult to perform integral molding.

  Therefore, in FIG. 15, in step S2B, a part obtained by dividing the blade 9A as necessary is manufactured, and this part is joined by a friction stir welding method to produce the blade 9A.

  In step S2c, the plate-like clad material produced in step S1 is cut out to a required size and formed into a blade component that is a part of the blade 9A having a U-shaped cross section.

  In step S2d, the blade 9A is manufactured by joining the plurality of blade parts formed in part of the blade 9A in step S2c by the friction stir welding method.

  In the present embodiment, for example, as shown in FIG. 16, a blade part 30A corresponding to a pair of opposed plate-like portions 9b of the blade 9A is formed, and a blade part 30B corresponding to the U-shaped cross-section bottom 9d of the blade 9A is formed. To do. Next, the respective ends of the U-shaped cross-section bottom portion 9d (blade component 30B) of the blade 9A are butted against one end of a pair of opposed plate-like portions 9b (blade component 30A) of the blade 9A and joined by friction stir welding. 9A is manufactured. The welding conditions by the friction stir welding method are the same as those in the first embodiment.

  According to the method for manufacturing the nuclear reactor control rod 1D of the present embodiment, a part obtained by dividing the blade 9A is manufactured, and the part is joined by a friction stir welding method to constitute the blade 9A to control the nuclear reactor. A rod 1D can be manufactured.

[Fifth Embodiment]
A fifth embodiment of a reactor control rod and a method for manufacturing a reactor control rod according to the present invention will be described with reference to FIGS. 17 to 18.

  In this nuclear reactor control rod 1E, the same components as those in the nuclear reactor control rod 1A of the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  FIGS. 17 to 18 are diagrams for explaining an outline of a method of manufacturing the blade 9A and fixing the tie rod 4A to constitute the wing 6B in the manufacturing method of the reactor control rod 1E. FIG. 17 is a process diagram for explaining a method of manufacturing the blade 9A and fixing the tie rod 4A to form the wing 6B in the manufacturing method of the nuclear reactor control rod 1E. FIG. 18 is a view for explaining a method of manufacturing the blade 9A from the components constituting the blade 9A having a U-shaped cross section.

  When a blade is manufactured by bending from a clad material in which a zircaloy material 18 and a hafnium material 19 are integrally formed, if the curvature of the bottom of the U-shaped cross section of the blade 9 is smaller than the minimum bending radius in the bending, the blade 9 There is a risk that it may be difficult to perform integral molding.

  Therefore, in FIG. 17, in step S2C, a part obtained by dividing the blade 9A as necessary is manufactured, and this part is welded by a laser welding method to manufacture the blade 9A.

  In step S2c, the plate-like clad material produced in step S1 is cut out to a required size and formed into a blade component that is a part of the blade 9A having a U-shaped cross section.

  In step S2e, the blade 9A is manufactured by welding a plurality of blade parts formed in part of the blade 9A in step S2c by laser welding.

  In the present embodiment, for example, as shown in FIG. 18, a blade component 30A corresponding to a pair of plate-like portions 9b opposed to the blade 9A is molded, and a blade component 30B corresponding to the U-shaped cross-section bottom portion 9d of the blade 9A is molded. To do. Next, each end of the U-shaped cross-section bottom portion 9d (blade component 30B) of the blade 9A is butted against one end of a pair of opposed plate-like portions 9b (blade component 30A) of the blade 9A and is welded by laser welding. Manufacturing. The welding conditions by the laser welding method depend on the welding conditions of the second embodiment.

  According to the method for manufacturing the reactor control rod 1E of the present embodiment, a part obtained by dividing the blade 9A as necessary is manufactured, and this part is welded by a laser welding method to constitute the blade 9A, thereby forming the reactor control rod. 1E can be manufactured.

[Sixth Embodiment]
A sixth embodiment of a reactor control rod and a method for manufacturing a reactor control rod according to the present invention will be described with reference to FIGS.

  In this nuclear reactor control rod 1F, the same components as those in the nuclear reactor control rod 1A of the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  The reactor control rod 1F includes, for example, a tie rod 4A having a cross-shaped cross section that joins the distal end structural member 2 and the end structural member 3 integrated with a handle, and a cross section projects radially from the tie rod 4A into a cross shape. The outer shell portion is constituted by a wing 6C having four blades 9B having an elongated rectangular cross section.

  FIG. 19 is a cross-sectional view schematically showing a sixth embodiment of the control rod for a reactor according to the present invention.

  As shown in FIG. 19, this nuclear reactor control rod 1F has a tie rod 4A having a substantially cross-shaped cross section in the central structural member. The blade 9B is configured by a plate-like clad material having a blade outer shell layer 15 made of Zircaloy material and a neutron absorbing element layer 16 made of hafnium material in a rectangular cross section. The blade 9B has a blade outer shell layer 15 on the outer surface and a neutron absorbing element layer 16 on the inner surface, and a gap 13 is formed between opposing plate-like portions of the neutron absorbing layer 16 on the inner surface. The cross-shaped portion of the cross section of the tie rod 4A has a thickness substantially equal to the thickness of the short side portion of the blade 9B having a rectangular cross section. The tie rod 4A and the blade 9B are attached to each other at this portion, and are fixed to each other by a short side portion having a rectangular cross section of the blade 9B.

  The nuclear reactor control rod 1F configured as described above does not require the load support member 8 that holds the sheath 5 and the hafnium metal plate 7 of the conventional nuclear reactor control rod 1. Accordingly, the wing 6C requires a hole corresponding to the sheath hole 10 of the sheath 5 constituting the wing 6 of the nuclear reactor control rod 1 and the mounting hole 7a of the load support member 8 provided in the hafnium metal plate 7. do not do. Further, there is no gap provided between the sheath 5 constituting the wing 6 of the nuclear reactor control rod 1 and the hafnium metal plate 7.

  20 to 21 are diagrams for explaining an outline of a method of manufacturing the blade 9B and fixing the tie rod 4A to form the wing 6C among the manufacturing method of the reactor control rod 1F. FIG. 20 is a view for explaining a method of manufacturing the blade 9B from the parts constituting the blade 9B having a rectangular cross section. FIG. 21 is a view for explaining a method of constituting the wing 6C by fixing the blade 9B to the tie rod 4A.

  When a blade is manufactured by bending from a clad material in which a zircaloy material 18 and a hafnium material 19 are integrally formed, if the curvature of the bottom of the U-shaped cross section of the blade 9 is smaller than the minimum bending radius in the bending, the blade 9 There is a risk that it may be difficult to perform integral molding.

  Therefore, in FIG. 15, in step S2B, a part obtained by dividing the blade 9B is manufactured, and the part is joined by a friction stir welding method to produce the blade 9B.

  In step S2c, the plate-like clad material manufactured in step S1 is cut out to a required size and formed into a blade component that is a part of the blade 9B having a U-shaped cross section.

  In step S2d, the blade 9B is manufactured by joining the plurality of blade parts formed in part of the blade 9B in step S2c by the friction stir welding method.

  In step S3, the tie rod 4A, which is the central structural member of the nuclear reactor control rod 1F, and the blade 9B manufactured in step S2B are joined by a friction stir welding method.

  In the present embodiment, for example, as shown in FIG. 20, a blade component 30A corresponding to a pair of opposing plate-like portions 9b of the blade 9B is formed, and the blade component 30B corresponding to the rectangular cross section short side portion 9e of the blade 9B is formed. Mold. Next, the respective ends of the rectangular cross section short side portion 9e (blade component 30B) of the blade 9B are butted against one ends of a pair of plate-like portions 9b (blade component 30A) opposed to the blade 9B, and are joined by a friction stir welding method. The blade 9B is manufactured. Next, as shown in FIG. 21, for example, one of the short sides 9e of the blade 9B having a rectangular cross section and the tip of the tie rod 4A having a cross-shaped cross section are attached to each other and bonded by a friction stir welding method. 25 is formed, and the blade 9B is fixed to the tie rod 4A. The welding conditions by the friction stir welding method are the same as those in the first embodiment.

  According to the method for manufacturing the nuclear reactor control rod 1F of the present embodiment, a part obtained by dividing the blade 9B is manufactured, and the part is joined by a friction stir welding method to constitute the blade 9B to control the nuclear reactor. The bar 1F can be manufactured.

  Further, by configuring the blade 9B to have a rectangular cross section, the handling and assembling properties are improved, and the tie rod 4A and the blade 9B can be easily joined.

[Seventh Embodiment]
A seventh embodiment of a reactor control rod and a method for manufacturing a reactor control rod according to the present invention will be described with reference to FIGS.

  In this nuclear reactor control rod 1G, the same components as those in the nuclear reactor control rod 1A of the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  22 to 23 are diagrams for explaining an outline of a method of manufacturing the blade 9B and fixing the tie rod 4A to constitute the wing 6C in the method of manufacturing the nuclear reactor control rod 1G. FIG. 22 is a diagram for explaining a method of manufacturing the blade 9B from the components constituting the blade 9B having a rectangular cross section. FIG. 23 is a view for explaining a method of constituting the wing 6C by fixing the blade 9B to the tie rod 4A.

  When a blade is manufactured by bending from a clad material in which a zircaloy material 18 and a hafnium material 19 are integrally formed, and the curvature of the bottom of the U-shaped cross section of the blade 9 is smaller than the minimum bending radius in the bending, the blade It may be difficult to integrally mold 9.

  Therefore, in FIG. 17, in step S2C, a part obtained by dividing the blade 9B is manufactured, and the part is welded by a laser welding method to manufacture the blade 9B.

  In step S2c, the plate-like clad material manufactured in step S1 is cut out to a required size and formed into a blade component that is a part of the blade 9B having a rectangular cross section.

  In step S2e, the blade 9B is manufactured by welding a plurality of blade parts formed in part of the blade 9B in step S2c by laser welding.

  In step S3A, the tie rod 4A, which is the central structural member of the nuclear reactor control rod 1G, and the blade 9B manufactured in step S2C are welded by a laser welding method to form the wing 6C.

  In the present embodiment, for example, as shown in FIG. 22, a blade component 30A corresponding to a pair of plate-like portions 9b opposed to the blade 9B is formed, and the blade component 30B corresponding to the rectangular cross section short side portion 9e of the blade 9B is formed. Mold. Next, the respective ends of the rectangular cross section short side portion 9e (blade component 30B) of the blade 9B are butted against one end of a pair of opposed plate-like portions 9b (blade component 30A) of the blade 9B and are welded by laser welding. 9B is manufactured. Next, for example, as shown in FIG. 23, one of the short sides 9e of the blade 9B having a rectangular cross section and the tip of the tie rod 4A having a cross-sectional shape are brought together and welded by a laser welding method. To fix the blade 9B to the tie rod 4A. The welding conditions by the laser welding method depend on the welding conditions of the second embodiment.

  According to the method of manufacturing the nuclear reactor control rod 1G of the present embodiment, a component obtained by dividing the blade 9B as necessary is manufactured, and this component is welded by a laser welding method to constitute the blade 9B, thereby forming the nuclear reactor control rod. 1G can be manufactured.

  Further, by configuring the blade 9B to have a rectangular cross section, the handleability and assemblability are improved, and the tie rod 4A and the blade 9B can be easily welded.

The perspective view of the load support member which serves as holding.
1 is a partially cut perspective view showing a first embodiment of a control rod for a nuclear reactor according to the present invention. BRIEF DESCRIPTION OF THE DRAWINGS The cross-sectional view which shows the outline of one blade among the four blades of 1st Embodiment of the control rod for nuclear reactors which concerns on this invention. The process drawing which shows the manufacturing method of the control rod for nuclear reactors which concerns on this invention, and manufactures the blade of 1st Embodiment, adheres to a tie rod, and comprises a wing. The manufacturing method of the control rod for nuclear reactors which concerns on this invention is shown, and explanatory drawing of the method of manufacturing the flat clad material which consists of the zircaloy material and hafnium material which are the materials of the blade of 1st Embodiment. The manufacturing method of the control rod for nuclear reactors which concerns on this invention is shown, and explanatory drawing of the method of manufacturing the flat clad material which consists of the zircaloy material and hafnium material which are the materials of the blade of 1st Embodiment. The manufacturing method of the control rod for nuclear reactors which concerns on this invention is shown, and explanatory drawing of the method of manufacturing the braid | blade of a U-shaped cross section from the flat clad material which consists of a zircaloy material and hafnium material of 1st Embodiment. The figure which shows the manufacturing method of the control rod for nuclear reactors which concerns on this invention, and is a figure explaining the method of adhering a braid | blade to the tie rod of 1st Embodiment, and comprising wings. The process drawing which shows the manufacturing method of the control rod for nuclear reactors which concerns on this invention, and manufactures the blade of 2nd Embodiment, adheres to a tie rod, and comprises a wing. The figure which shows the manufacturing method of the control rod for reactors which concerns on this invention, Comprising: The figure explaining the method of adhering a braid | blade to the tie rod of 2nd Embodiment, and comprising wings. The manufacturing method of the control rod for nuclear reactors which concerns on this invention is shown, and it is process drawing explaining the method of manufacturing the braid | blade of 3rd Embodiment and adhering to a tie rod, and comprising a wing. The figure which shows the manufacturing method of the control rod for nuclear reactors which concerns on this invention, and is a figure explaining the shape structure of the braid | blade of the U-shaped cross section of 3rd Embodiment. The manufacturing method of the control rod for nuclear reactors which concerns on this invention is shown, and description of the method of manufacturing the component which comprises the braid | blade of a U-shaped cross section from the flat clad material which consists of a zircaloy material and a hafnium material of 3rd Embodiment. Figure. The figure which shows the manufacturing method of the control rod for reactors which concerns on this invention, and is a figure explaining the method to manufacture a braid | blade from the components which comprise the braid | blade of a U-shaped cross section of 3rd Embodiment. The cross-sectional view which shows the outline of 4th Embodiment of the control rod for reactors which concerns on this invention. The process drawing which shows the manufacturing method of the control rod for nuclear reactors which concerns on this invention, and manufactures the braid | blade of 4th Embodiment, adheres to a tie rod, and comprises a wing. The figure which shows the manufacturing method of the control rod for reactors which concerns on this invention, Comprising: The figure explaining the method to manufacture a braid | blade from the components which comprise the braid | blade of a U-shaped cross section of 4th Embodiment. The process drawing which shows the manufacturing method of the control rod for nuclear reactors which concerns on this invention, and manufactures the blade of 5th Embodiment, adheres to a tie rod, and comprises a wing. The figure which shows the manufacturing method of the control rod for reactors which concerns on this invention, Comprising: The figure explaining the method to manufacture a blade from the components which comprise the braid | blade of a U-shaped cross section of 5th Embodiment. The cross-sectional view which shows the outline of 6th Embodiment of the control rod for nuclear reactors which concerns on this invention. The figure which shows the manufacturing method of the control rod for reactors which concerns on this invention, and is a figure explaining the method to manufacture a braid | blade from the components which comprise the braid | blade of the rectangular cross section of 6th Embodiment. The figure which shows the manufacturing method of the control rod for reactors which concerns on this invention, Comprising: The figure explaining the method of adhering a braid | blade to the tie rod of 6th Embodiment, and comprising wings. The figure which shows the manufacturing method of the control rod for nuclear reactors which concerns on this invention, and is a figure explaining the method to manufacture a braid | blade from the components which comprise the braid | blade of the rectangular cross section of 7th Embodiment. The figure which shows the manufacturing method of the control rod for reactors which concerns on this invention, Comprising: The figure explaining the method of adhering a braid | blade to the tie rod of 7th Embodiment, and comprising wings. The partial cutaway perspective view of the conventional control rod for nuclear reactors. The cross-sectional view which shows the outline of one wing among the four wings of the cross-shaped cross section of the conventional nuclear reactor control rod. The perspective view of the load support member which serves also as the gap maintenance of the sheath which comprises the conventional nuclear reactor control rod, and a hafnium metal plate.

Explanation of symbols

1, 1A, 1B, 1C, 1D, 1E, 1F, 1G Reactor control rod 2 End structure material 3 End structure material 4, 4A Tie rod 5 Sheath 6, 6A, 6B, 6C Wing 7 Hafnium metal plate 8 Load support member 8a Interval holding part 8b Support shaft 9, 9A, 9B Blade 9a Semi-arc part 9b Plate-like part 9c 1/4 arc part 9d Co-shaped cross-section bottom part 9e Rectangular short section 10 Sheath hole 11 Water hole 13 Water gap 14 Speed Limiter 15 Blade outer shell layer 16 Neutron absorbing element layer 18 Zircaloy material 19 Hafnium material 21 Rolling machine 22 Gunpowder 23 Rotating tool 25 Tie rod / blade joint 27 Laser welding device 27a Laser beam 28 Tie rod / blade weld 30, 30A, 30B Blade parts

Claims (6)

A long blade with a deep U-shaped cross-section is fixed to the central structural member to form a cross-shaped cross-shaped wing. In the reactor control rod provided with a neutron absorbing element in the blade, respectively, while fixing the material,
The blade is configured by forming a plate-like clad material having a blade outer shell layer made of zircaloy material and a neutron absorbing element layer made of hafnium material into a U-shape with a deep transverse section. Control rod for furnace. In the blade, a blade outer shell layer and a neutron absorption layer are integrally laminated to form a clad material, and the clad material is formed in a U shape having a deep transverse cross section and is fixed to the central structure material. The reactor control rod according to claim 1, wherein a cross-shaped wing is configured. 3. The nuclear reactor control rod according to claim 1, wherein the blade has a blade outer shell layer formed on an outer surface of the blade and a neutron absorption layer formed on an inner surface of the blade. 4. A step of producing a plate-like clad material by press-contacting a hafnium material and a zircaloy material;
Forming the clad material into a long blade shape having a U-shape with a deep cross section by bending; and
A method of manufacturing a control rod for a nuclear reactor comprising a step of fixing a U-shaped opening of a cross section of the blade to a central structural member by a friction stir welding method to form a cross-shaped cross-shaped wing . A step of producing a plate-like clad material by press-contacting a hafnium material and a zircaloy material;
Forming the clad material into a long blade shape having a U-shape with a deep cross section by bending; and
A method of manufacturing a control rod for a nuclear reactor, comprising: a step of fixing a U-shaped opening of the blade to a central structural member by a laser welding method to form a cross-shaped cross-shaped wing. Cutting the cladding material into a required size and forming a blade member constituting a part of a long blade shape having a U-shaped cross section by bending; and
A method of manufacturing a control rod for a nuclear reactor according to claim 4 or 5, further comprising a step of manufacturing the blade by fixing the blade member by a laser welding method.

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