CN103971768B - A kind of fuel rod replacing mechanical hand based on distortional strain energy density theory - Google Patents

Abstract

The invention discloses a kind of fuel rod replacing mechanical hand, including core bar, elastic jaw and locking sleeve, wherein core bar is for sensing the position of fuel rod, elastic jaw has multiple jaw, this elasticity jaw relatively can move axially and makes the plurality of jaw be positioned at fuel rod periphery by locking sleeve, make multiple jaw can clamp fuel rod, thus realize the crawl of nuclear fuel rod；Each jaw identical with the curvature of locking sleeve inwall curved surface with the curvature of the outside curve of locking sleeve contact internal walls, and its outside curve and elastic jaw axis parallel when multiple jaws are in blessing state；The curvature of the pawl point curved surface contacted with fuel rod of each jaw is less than fuel rod cervical region curvature of curved surface, and its pawl point curved surface and elastic jaw axis parallel when multiple jaws are in blessing state.Present configuration is ingenious, makes mechanical hand reliability when capturing fuel rod higher, and fatigue resistance is more preferable, by other actuating mechanism controls locking sleeve, elastic jaw, the relative motion of core bar, it is achieved that the crawl to fuel rod.

Description

A kind of fuel rod replacing mechanical hand based on distortional strain energy density theory

Technical field

The invention belongs to mechanical hand field, relate to a kind of fuel rod replacing mechanical hand, this mechanical hand is more There is when changing fuel rod higher reliability and fatigue resistance.

Background technology

For improving fuel assembly utilization rate and the economy of power plant, impaired for assembly and the most maximum The irradiated fuel assembly of burnup, on the premise of ensureing fuel assembly and reactor core safety, it may be considered that enter Row is repaired and is reentered heap and uses, and fuel rod is extracted from damaged component or inserted is fuel assembly reparation dress Standby important step.Nuclear fuel jaw is directly with core fires during nuclear reactor first fuel loading and overhaul The core actuator of material component touch, is the core component of a whole set of nuclear fuel handling storage system equipment, Fuel rod is extracted from damaged component or is inserted and mainly realized by this jaw, and can it by predetermined design Whether smooth opening and the tightening up work that is related to reload can smoothly complete, and its security reliability is whole changing The guarantee that material process is normally smoothed out.

United States Patent (USP) US4,903,281 disclose the collet that a kind of fuel rod captures, but this elasticity The shortcoming of chuck is: when there is power-off, and the overcoat whereabouts that runs out of steam can cause fuel rod from jaw Abjection, reliability is low, dangerous.

Chinese patent application 94193513.2 discloses the charging appliance of a kind of fuel stringer assembly, this equipment In include the clamp device of a fuel rod, but the shortcoming of this device is: collet is to fuel The locking of rod places one's entire reliance upon the clamping of outer tube, and this clamping device is less reliable when clamping fuel rod, The safest.

For above-mentioned chuck, the locking of fuel rod is completely dependent on outer tube clamping and makes less reliable and safety Defect, Chinese patent CN101271738A propose a kind of improvement fuel rod replacing device folder Head, specifically, this chuck includes locking sleeve and the elastic clip head tube being arranged in locking sleeve, lock Tight casing part has an enlarging conical surface, elastic clip head tube lower end inside to match with fuel caput, elastic Being provided with enlarging tube expansion in chuck pipe, its lower end inner wall is provided with the swollen head of arc of at least one pair of convex, expands Being provided with, in mouth tube expansion, the plug that can slide up and down, it can be realized combustion by lifting and lower the inserting of plug The crawl of charge bar and disengaging, and clamping force and the lock of collet itself can be relied on after capturing fuel rod The clamping force of tight sleeve pipe locks grappling fixture, jointly so that the crawl of fuel rod is safe and reliable.

This cartridge device not exclusively relies on outer tube and locks so that reliability and safety greatly improve, But, in this device, due to clamping face in collet tube head part and locking sleeve etc. and combustion In the contact of charge bar and clamping face, still use traditional structure so that capturing or clamping fuel rod During, its reliability is the most not high enough, and fatigue resistance is poor.

Summary of the invention

It is an object of the invention to provide a kind of mechanical hand optimized based on distortional strain energy density theory, its energy Make actuator pass through action simply and realize the crawl to fuel rod and disengaging, and locking effect is good. Reliability and the fatigue resistance of height still can be kept in frequently capturing.

For achieving the above object, the concrete technical scheme that the present invention uses is as follows:

A kind of fuel rod replacing mechanical hand, is used for capturing nuclear fuel rod so that fuel rod is from fuel assembly Extracting or insert, it is achieved the charging of fuel rod and replacing, wherein, this mechanical hand includes same from the inside to the outside The core bar that axle is set with successively, elastic jaw and locking sleeve, wherein said core bar can the most described elasticity Jaw moves axially and stretches out from its one end or retract, for sensing the position of fuel rod, described elasticity Jaw can move axially and can stretch out from its one end or retract by the most described locking sleeve, and it has along institute State the peripheral axial arranged multiple jaws of core bar, for this bullet after described plug determines fuel rod position Property jaw moves axially relative to locking sleeve and makes the plurality of jaw be positioned at described fuel rod periphery, thus can Make, when described locking sleeve moves axially and makes this elasticity jaw be placed in wherein completely, can pass through Inwall applies squeezing action power to described elastic jaw so that above-mentioned multiple jaws can clamp fuel rod, Thus realize the crawl of nuclear fuel rod；

It is characterized in that, the outside curve with locking sleeve contact internal walls of the described elastic each jaw of jaw Curvature identical with the curvature of locking sleeve inwall curved surface, and be in blessing state at above-mentioned multiple jaws Time its outside curve and elastic jaw axis parallel；

Meanwhile, the curvature of the pawl point curved surface contacted with fuel rod of described each jaw is less than fuel rod cervical region Curvature phase, and when above-mentioned multiple jaws are in blessing state, its pawl point curved surface and elastic jaw axle center Parallel.

As the improvement of the present invention, when the plurality of jaw is in blessing state, its outside curve is with elastic Jaw axis parallel realizes by compensating angle in the processing of jaw outside curve.

As the improvement of the present invention, when the plurality of jaw is in blessing state, its pawl point curved surface is with elastic Jaw axis parallel realizes by compensating angle in pawl point Machining of Curved Surface.

As the improvement of the present invention, described compensation angle is:

$\mathrm{\θ}=\frac{3y}{2L}$

Wherein, y is the amount of deflection of pawl head elasticity jaw pawl head, and L is the length of single jaw.

As the improvement of the present invention, described locking sleeve with elastic jaw relative movement and external part The described elastic jaw of end edge and correspondence is provided with rounding.

As the improvement of the present invention, the jaw of elastic jaw is uniformly distributed along plug circumference, jaw quantity At least two, is preferably six in the present embodiment.

As the improvement of the present invention, the gap length between described elastic jaw pawl head is according to elastic jaw After compression, jaw head camber line determines relative to decrement, and specially pawl head is after compression completely, along pawl The arc length value that head external circumferential reduces obtains divided by concrete pawl head number.

The invention also discloses the application in the feeding of nuclear fuel rod or replacing of a kind of above-mentioned mechanical hand.

In the present invention, mechanical hand is made up of locking sleeve, elastic jaw, core bar；Locking sleeve edge There is rounding, when being mainly used in locking elastic jaw, turning rounding off, reduce rubbing between assembly Wipe, increase the fatigue resistance of mechanical hand；There is rounding in elastic jaw corner, is mainly used in reducing The stress raisers of elastic jaw, increase reliability and the fatigue resistance of elastic jaw；Elastic clip The pawl number at least two of pawl；The outside curve of elastic jaw pawl head is carried out according to distortional strain energy density theory Optimize, greatly reduce the contact stress between elastic jaw and locking sleeve after optimization, greatly Add the fatigue resistance of mechanical hand；The pawl point curved surface of elastic jaw pawl head is managed according to distortional strain energy density Opinion is optimized, and greatly reduces the contact stress between elastic jaw and fuel rod after optimization, or Person adds the position error allowable in elastic jaw axle center and fuel rod axle center relatively；Elastic jaw pawl head Inner curve and fuel rod head curved surface coincide；Core bar is applied in elastic jaw, is used for sensing machine Distance between tool hands and fuel rod, when fuel rod head encountered by core bar, locking sleeve and elastic clip Pawl starts effect.

In the present invention, the outside curve of elastic jaw pawl head is optimized portion according to distortional strain energy density theory Point, concrete optimization embodies everywhere；At first, the outside curve at pawl head increases by one manufacturing procedure, Make outside curve curvature identical with curvature inside locking sleeve；At second, the outside curve at pawl head increases Add a processing and compensate angle θ, when this compensation angle makes jaw be in blessing state, curved surface and elastic jaw axle The heart is parallel；At 3rd, the pawl point curved surface at pawl head increases by one manufacturing procedure, makes the song of pawl point curved surface Rate is less than fuel rod cervical region curvature；The everywhere, and the pawl point curved surface at pawl head increases a processing and compensates angle θ, When this compensation angle makes jaw be in blessing state, pawl point curved surface and elastic jaw axis parallel.

In general, hinge structure of the present invention, have the following technical effect that

(1), in the present invention, the outside curve of elastic jaw pawl head carries out excellent according to distortional strain energy density theory Change, greatly reduce the contact stress between elastic jaw and locking sleeve after optimization, greatly increase Add the fatigue resistance of mechanical hand；

(2), in the present invention, the pawl point curved surface of elastic jaw pawl head carries out excellent according to distortional strain energy density theory Change, greatly reduce the contact stress between elastic jaw and fuel rod after optimization, or relatively increase Add the position error allowable in elastic jaw axle center and fuel rod axle center；

(3) there is rounding at locking sleeve edge, when being mainly used in locking elastic jaw, and the round and smooth mistake in turning Cross, reduce the friction between assembly, increase the fatigue resistance of mechanical hand；

(4) there is rounding in elastic jaw corner, is mainly used in reducing the local stress collection of elastic jaw In, increase reliability and the fatigue resistance of elastic jaw.

Accompanying drawing explanation

Fig. 1 is the fuel rod replacing mechanical hand based on distortional strain energy density theory of one embodiment of the invention Schematic diagram.

Fig. 2 is the fuel rod replacing manipulator example schematic diagram of one embodiment of the invention, this mechanical hand There are six jaws, and elastic jaw is in open configuration.

Fig. 3 is the fuel rod replacing manipulator example schematic diagram of one embodiment of the invention, this mechanical hand There are six jaws, and elastic jaw is in closure state.

Fig. 4 is the partial enlarged drawing of six jaw manipulator example described in Fig. 2, and this partial enlarged drawing is pawl Head part, and elastic jaw is in open configuration.

Fig. 5 is that the local that six jaw manipulator example described in Fig. 3 process through distortion energy theory optimization is put Big figure, this partial enlarged drawing is the contact position of elastic jaw pawl head and locking sleeve, and elastic clip Pawl is in closure state.

Fig. 6 is the office that six jaw manipulator example described in Fig. 3 do not process through distortion energy theory optimization Portion's enlarged drawing, this partial enlarged drawing is the contact position of elastic jaw pawl head and locking sleeve, and bullet Property jaw is in closure state.

Fig. 7 is the right view of Fig. 5.

Fig. 8 is the right view of Fig. 6.

Fig. 9 is a component diagram of six jaw manipulator example described in Fig. 3, and this assembly is locking Sleeve.

Figure 10 is a component diagram of six jaw manipulator example described in Fig. 3, and this assembly is elastic Jaw.

Figure 11 is the right view of Figure 10.

Figure 12 is a component diagram of six jaw manipulator example described in Fig. 3, and this assembly is core bar.

Figure 13 is the fuel rod replacing mechanical hand based on distortional strain energy density theory of one embodiment of the invention Three-dimensional structure diagram.

Figure 14 is the fuel rod replacing mechanical hand based on distortional strain energy density theory of one embodiment of the invention Decomposing schematic representation.

Detailed description of the invention

In order to make the purpose of the present invention, technical scheme and advantage clearer, below in conjunction with accompanying drawing And embodiment, the present invention is further elaborated.Should be appreciated that described herein specifically Embodiment only in order to explain the present invention, is not intended to limit the present invention.Additionally, it is disclosed below Just may be used as long as technical characteristic involved in each embodiment of the present invention does not constitutes conflict each other To be mutually combined.

As in figure 2 it is shown, a kind of fuel rod mechanical hand based on distortional strain energy density theory, depend on from outside to inside Secondary locking sleeve 1, elastic jaw 2, the core bar 3 of including, in pawl number the present embodiment of elastic jaw preferably It is six, but jaw quantity is not specifically limited by the present invention.

Locking sleeve 1 edge has rounding 10, elastic jaw 2 corner to have rounding, elastic jaw The pawl number at least two of 2, is preferably six in the present embodiment, the outside curve of elastic jaw pawl head 4 It is optimized according to distortional strain energy density theory with pawl point curved surface 6, the inner curve 7 of pawl head 4 and fuel Club head curved surface coincide；Core bar 3 is applied in elastic jaw 2, for sensing fuel rod distance.

Outside curve 5 and the pawl point curved surface 6 of elastic jaw pawl head 4 are carried out according to distortional strain energy density theory Optimizing part, concrete optimization embodies everywhere.

At first, the outside curve 5 at pawl head 4 increases by one manufacturing procedure, makes outside curve 5 bent Rate is identical with curvature inside locking sleeve 1.At second, the outside curve 5 at pawl head 4 increases by one Processing compensates angle θ, and when this compensation angle makes jaw be in blessing state, curved surface is put down with elastic jaw 2 axle center OK, now the critical angle of elastic jaw head meets ∠ BCD=∠ ABC+ θ (such as Fig. 4), such as figure four, This angle is the acute angle that straight line AB intersects with straight line CD, and wherein processing compensation angle refers to, elastic clip Pawl pawl head outside curve adds man-hour, and the blade of cutter is parallel to process in the axial direction, by cutting edge roundness After tilting an angle becoming θ with axis, what processing obtained in this way is what above-mentioned compensation angle obtained Curved surface, therefore this angle is become processing and compensates angle, the specific size at this compensation angle should meet so that jaw Outside curve and axis parallel when clamp position.It practice, outside curve is pawl head outside left Curved surface, axle center is elastic jaw or core bar, the revolution axle center of locking sleeve.Part at assembled, Can be matched with axle center by curved surface.Therefore at outside curve herein and axis parallel, it is outside bent Cylinder axle center, place, face and the revolution axis parallel of elastic jaw.

Before and after optimization contact form contrast, as Fig. 8 Yu Fig. 7 contrast contact form by some E, F (or E ', F ') become camber line EF (camber line E ' F '), as Fig. 6 Yu Fig. 5 contrasts contact form by a C ' line Section C ' D '.

At 3rd, the pawl point curved surface 6 at pawl head 4 increases by one manufacturing procedure, makes pawl point curved surface 6 Curvature is less than fuel rod cervical region curvature, increases elastic jaw axle center and positions by mistake with the allowable of fuel rod axle center Difference.The everywhere, and the pawl point curved surface 6 at pawl head 4 increases a processing and compensates angle θ, and this compensation angle makes folder When pawl is in blessing state, pawl point curved surface 6 and elastic jaw 2 axis parallel.

After optimization, when elastic jaw is in compressive state, at pawl point, camber line intersection is cusp, optimizes Rear multiple camber lines form a circle, have eliminated cusp.

Similarly, processing compensates angle and refers to, elastic jaw pawl head outside curve adds man-hour, the cutter of cutter Sword is parallel to process in the axial direction, after cutting edge roundness is tilted an angle becoming θ with axis, by this Mode processes the curved surface that above-mentioned compensation angle obtains that is obtained, therefore this angle becomes processing and compensates angle, The specific size at this compensation angle should meet so that pawl point curved surface 6 and elastic jaw 2 axis parallel.Pawl point Curved surface is the curved surface that pawl point outer surface is formed, and axle center is elastic jaw or core bar, locking sleeve Revolution axle center.Part, at assembled, can be matched with axle center by curved surface.Therefore in outside herein Curved surface and axis parallel, be the revolution axis parallel in cylinder axle center, pawl point curved surface place and elastic jaw.

Jaw when clamp position the big I in gap 11 between elasticity jaw pawl head 6 according to elastic jaw After compression, jaw head camber line determines relative to decrement, be specifically as follows pawl head 4 completely compression after, The arc length value reduced along pawl head 4 external circumferential obtains divided by concrete pawl head number.

In the present invention, fuel rod mechanical hand after distortion energy theory optimizes, elastic jaw and lock sleeve Cylinder, elastic jaw are changed to face with the contact form of fuel rod by original point cantact and contact, thus pole The big fatigue resistance adding mechanical hand, or relatively add the location allowable of end effector Error.

The distortional strain energy density theory that the present invention relates to is as follows:

1st step: according to distortional strain energy density theory, the main cause of jaw generation placticity failure is distortion Density can reach the limit values, i.e. obtain the condition that jaw did not lost efficacy: u_d≤u_du, wherein, u_dAt material Distortional strain energy density value when complex stress, and $u_d=\frac{1+\mathrm{\μ}}{6E}[{({\mathrm{\σ}}_1-{\mathrm{\σ}}_2)}^2+{({\mathrm{\σ}}_2-{\mathrm{\σ}}_3)}^2+{({\mathrm{\σ}}_3-{\mathrm{\σ}}_1)}^2],$ u_du Distortional strain energy DENSITY LIMIT value when being in complex stress for material, and

2nd step: the formula of the 1st step of deriving, can obtain intensity bar based on distortional strain energy density theory Part: $\sqrt{\frac{1}{2}[{({\mathrm{\σ}}_1-{\mathrm{\σ}}_2)}^2+{({\mathrm{\σ}}_2-{\mathrm{\σ}}_3)}^2+{({\mathrm{\σ}}_3-{\mathrm{\σ}}_1)}^2]}\≤{\mathrm{\σ}}_s,$ Wherein, σ₁,σ₂,σ₃It is in complex stress for material Time three principal stresses, and σ in the robot₁＞ ＞ σ₂≥σ₃, σ_sFor jaw or locking sleeve material Yield stress.

3rd step: the formula of the 2nd step of deriving, can obtain

$\max ({\mathrm{\σ}}_s-\sqrt{\frac{1}{2}[{({\mathrm{\σ}}_1-{\mathrm{\σ}}_2)}^2+{({\mathrm{\σ}}_2-{\mathrm{\σ}}_3)}^2+{({\mathrm{\σ}}_3-{\mathrm{\σ}}_1)}^2]})$

I.e.

$\max ({\mathrm{\σ}}_s-\sqrt{\frac{1}{2}[{({\mathrm{\σ}}_x-{\mathrm{\σ}}_y)}^2+{({\mathrm{\σ}}_y-{\mathrm{\σ}}_z)}^2+{({\mathrm{\σ}}_z-{\mathrm{\σ}}_z)}^2]+3({{\mathrm{\τ}}_{\mathrm{xy}}}^2+{{\mathrm{\τ}}_{\mathrm{yz}}}^2+{{\mathrm{\τ}}_{\mathrm{zx}}}^2)})$

When $\max ({\mathrm{\σ}}_s-\sqrt{\frac{1}{2}[{({\mathrm{\σ}}_x-{\mathrm{\σ}}_y)}^2+{({\mathrm{\σ}}_y-{\mathrm{\σ}}_z)}^2+{({\mathrm{\σ}}_z-{\mathrm{\σ}}_z)}^2]+3({{\mathrm{\τ}}_{\mathrm{xy}}}^2+{{\mathrm{\τ}}_{\mathrm{yz}}}^2+{{\mathrm{\τ}}_{\mathrm{zx}}}^2)})$ Time the biggest, resisting of mechanical hand Fatigue properties are the best, owing to elastic jaw is laterally main by resilient force, i.e. and σ_y≈ 0, σ_z≈ 0, τ_xy≈ 0, τ_yz≈ 0, τ_zx≈ 0, therefore formula can be reduced to

max(σ_s-σ_x)

4th step: according to the 3rd step conclusion, can only change mechanical hand structure and reduce σ_x, according to Derive, increase the contact area of elastic jaw and locking sleeve, or reduce elastic jaw and lock sleeve Elastic force between Tong, can reduce σ_x, thus increase the fatigue resistance of mechanical hand.

5th step: according to the 4th step conclusion, proposes four kinds of concrete prioritization schemes；At first, at pawl head Outside curve increases by one manufacturing procedure, makes outside curve curvature identical with curvature inside locking sleeve, Elastic jaw is made to be become linear contact lay with locking sleeve by point cantact；At second, increase at pawl head outside curve Add a processing and compensate angle θ, when this compensation angle makes jaw be in blessing state, curved surface and elastic jaw axle The heart is parallel, makes elastic jaw be become face contact, now elastic jaw with locking sleeve by linear contact lay The critical angle of head meets ∠ BCD=∠ ABC+ θ (such as Fig. 4)；At 3rd, bent at the pawl point of pawl head Face increases by one manufacturing procedure, makes pawl point curvature of curved surface less than fuel rod cervical region curvature, increases elastic clip Pawl axle center and the position error allowable in fuel rod axle center；The everywhere, and the pawl point curved surface at pawl head increases by one Individual processing compensates angle θ, when this compensation angle makes jaw be in blessing state, and pawl point curved surface and elastic jaw axle The heart is parallel.

The concrete value of curvature of pawl point curved surface can be determined by following formula,

$\frac{1}{{\mathrm{\ρ}}_1}=\frac{1}{{\mathrm{\ρ}}_2}+{\mathrm{\Δ}}_x,$ I.e. ${\mathrm{\ρ}}_1=\frac{{\mathrm{\ρ}}_2}{1+{\mathrm{\ρ}}_2{\mathrm{\Δ}}_x}$

Wherein, ρ₁For the curvature of pawl point curved surface, ρ₂For the curvature of fuel rod cervical region curved surface, Δ_xElastic clip Pawl axle center and the position error allowable in fuel rod axle center.

6th step: compensate angle θ in the 5th step and deform fundamental equation according to beam, derive

$\left\{\begin{array}{c}\mathrm{\θ}=y^{\′}=\∫\frac{M\left(x\right)}{\mathrm{EI}}\mathrm{dx}+C_1\\ y=\∫(\∫\frac{M\left(x\right)}{\mathrm{EI}}\mathrm{dx}+C_1)\mathrm{dx}+C_2\end{array}\right.,$

Substitute into boundary condition, can deriveWherein, y be pawl head elasticity jaw pawl head amount of deflection (as Fig. 4 elasticity jaw is not closed makes the C ' after C point and elastic jaw Guan Bi, at vertical spring jaw axis Displacement on direction), L is that in the length of single jaw, i.e. Fig. 4 A, B 2 be in the axial direction Distance.

Mechanical hand after distortion energy theory optimizes, elastic jaw with the contact form of locking sleeve by former The point cantact come is changed to face contact, and elastic jaw axle center increases with the position error allowable in fuel rod axle center Greatly, thus significantly increase the fatigue resistance of mechanical hand.Specifically contact form is as shown in drawings, Contact position (8) after distortion energy theory optimizes and Fig. 7, after optimizing without distortion energy theory Contact position (9) and Fig. 8.

It is as follows that above-mentioned fuel rod mechanical hand based on distortional strain energy density theory specifically captures fuel rod process:

1) fuel rod is captured

As in figure 2 it is shown, the core bar 3 of the embodiment of the present invention to be directed at the head of fuel rod, and by the machine of execution Structure control mechanical hand is close to fuel rod, when core bar 3 head touches fuel rod head, and elastic jaw 2 Being begun to decline a distance to a declared goal by actuating mechanism controls, locking sleeve 1 starts toward declining one subsequently Distance to a declared goal, and just pin elastic jaw 2, actuator subsequently carries out pull transfer to fuel rod. (as shown in Figure 3)

2) fuel rod is departed from

When needs mechanical hand departs from fuel rod, actuating mechanism controls locking sleeve 1 rise an appointment Distance, elastic jaw 2 begins to ramp up a distance to a declared goal subsequently, and actuator subsequently can be by mechanical hand Remove.

As it will be easily appreciated by one skilled in the art that and the foregoing is only presently preferred embodiments of the present invention, Not in order to limit the present invention, all made within the spirit and principles in the present invention any amendment, etc. With replacement and improvement etc., should be included within the scope of the present invention.

Claims (8)

1. a fuel rod replacing mechanical hand, is used for capturing nuclear fuel rod so that fuel rod is from fuel assembly In extract or insert, it is achieved the charging of fuel rod and replacing, wherein, this mechanical hand includes from the inside to the outside Coaxial core bar, elastic jaw and the locking sleeve being set with successively, wherein said core bar can the most described bullet Property jaw move axially and stretch out from its one end or retract, for sensing the position of fuel rod, described bullet Property jaw can move axially and can stretch out from its one end or retract by the most described locking sleeve, and it has edge The peripheral axial arranged multiple jaws of described core bar, for being somebody's turn to do after described core bar determines fuel rod position Elastic jaw moves axially relative to locking sleeve and makes the plurality of jaw be positioned at described fuel rod periphery, thus Can make, when described locking sleeve moves axially and makes this elasticity jaw be placed in wherein completely, can lead to Cross inwall and apply squeezing action power to described elastic jaw so that above-mentioned multiple jaws can clamp fuel rod, Thus realize the crawl of nuclear fuel rod；

It is characterized in that, the outside curve with locking sleeve contact internal walls of the described elastic each jaw of jaw Curvature identical with the curvature of locking sleeve inwall curved surface, and be in blessing state at above-mentioned multiple jaws Time its outside curve and elastic jaw axis parallel；Meanwhile, the contacting with fuel rod of described each jaw The curvature of pawl point curved surface is less than the curvature of fuel rod cervical region curved surface, and is in blessing at above-mentioned multiple jaws During state, its pawl point curved surface and elastic jaw axis parallel；

Wherein, the concrete value of curvature of described pawl point curved surface can be determined by following formula:

$\frac{1}{{\mathrm{\ρ}}_1}=\frac{1}{{\mathrm{\ρ}}_2}+{\mathrm{\Δ}}_x$

In formula, ρ₁For the curvature of pawl point curved surface, ρ₂For the curvature of fuel rod cervical region curved surface, Δ_xElastic clip Pawl axle center and the position error allowable in fuel rod axle center.

A kind of fuel rod replacing mechanical hand the most according to claim 1, wherein, at described jaw When the state of blessing, its outside curve and elastic jaw axis parallel are by mending in the processing of jaw outside curve Repay angle to realize.

A kind of fuel rod replacing mechanical hand the most according to claim 1, wherein, the plurality of folder When pawl is in blessing state, its pawl point curved surface and elastic jaw axis parallel are by mending in pawl point Machining of Curved Surface Repay angle to realize.

4. according to a kind of fuel rod replacing mechanical hand described in Claims 2 or 3, wherein, described benefit Repaying angle is:

$\mathrm{\θ}=\frac{3y}{2L}$

Wherein, y is the amount of deflection of pawl head elasticity jaw pawl head, and L is the length of single jaw.

5. according to a kind of fuel rod replacing mechanical hand according to any one of claim 1-3, wherein, Described locking sleeve with elastic jaw relative movement and external part end edge and corresponding institute State elastic jaw and be provided with rounding.

6. according to a kind of fuel rod replacing mechanical hand according to any one of claim 1-3, wherein, The jaw of elastic jaw is uniformly distributed along plug circumference, jaw quantity at least two.

7. according to a kind of fuel rod replacing mechanical hand according to any one of claim 1-3, wherein, After gap length between described elastic jaw pawl head is according to elastic jaw compression, jaw head camber line phase Determining decrement, specially pawl head is after compression completely, and the camber line reduced along pawl head external circumferential is long Angle value obtains divided by concrete pawl head number.

8. the mechanical hand according to any one of claim 1-7 is in the feeding or replacing of nuclear fuel rod Application.