Method and apparatus for handling an irradiated fuel assembly

Claim 2

Apparatus for handling irradiated fuel assemblies of a nuclear reactor during underwater transfer operations, said apparatus comprising means for lifting and lowering a fuel assembly, means for moving the fuel assembly in a horizontal direction, first support means for structurally supporting the fuel assembly during the handling operations, said first support means including apparatus for grasping the fuel assembly, and second support means for redundantly supporting the fuel assembly, said second support means including apparatus for redundantly grasping the fuel assembly, said redundant grasping apparatus being activated so as to engage the fuel assembly by lifting of the fuel assembly with said lifting means.

Claim 3

The apparatus of claim 1 including dashpot means interposed between said redundant support and said redundant gasping apparatus for preventing rapid lowering of the fuel assembly from a raised position.

Claim 4

The apparatus of claim 1 including latching means for fixedly coupling a raised fuel assembly to said second support means, said latching means being activated by the fuel assembly when The fuel assembly is lifted to a predetermined height.

Claim 5

Apparatus for handling irradiated fuel assemblies of a nuclear reactor during underwater transfer operations, said apparatus comprising: a bridge-like structure positioned over a container having at least one irradiated fuel assembly positioned therein, said bridge-like structure being mounted for movement on track apparatus, fuel assembly handling means for grasping, vertically lifting, vertically lowering and releasing said irradiated fuel assembly, said fuel handling means being movably mounted to said bridge-like structure for axial and horizontal movement thereon, trolley means mounted to said bridge-like structure for travel thereon in a horizontal direction, an elongated rod member fixedly connected at one end to said trolley means, said rod member extending in a generally vertical direction and having its other end terminate at a location proximate an end of said irradiated fuel assembly, and latching means for providing redundant grasping of said irradiated fuel assembly during handling of said irradiated fuel assembly, said latching means being movably connected to said rod member for axial movement thereon.

Claim 6

Apparatus for handling irradiated fuel assemblies of a nuclear reactor during underwater transfer operations, said apparatus comprising: a bridge-like structure positioned over a container having at least one irradiated fuel assembly positioned therein, said bridge-like structure being mounted for movement on track apparatus, fuel assembly handling means for grasping, vertically lifting, vertically lowering and releasing said irradiated fuel assembly, said fuel handling means being movably mounted to said bridge-like structure for axial and horizontal movement thereon, trolley means mounted to said bridge-like structure for travel thereon in a horizontal direction, an elongated rod member fixedly connected at one end to said trolley means, said rod member extending in a generally vertical direction and having its other end terminate at a location proximate an end of said irradiated fuel assembly, and latching means for providing redundant grasping of said irradiated fuel assembly during handling of said irradiated fuel assembly, said latching means being movably connected to said rod member for axial movement thereon.

Claim 7

The apparatus of claim 4 including latch blocks pivotally connected to said rod member for locking said irradiated fuel assembly in a raised position for horizontal transfer of said irradiated fuel assembly.

Claim 8

The apparatus of claim 4, wherein said rod member comprises a tube with said fuel handling means passing through the interior thereof.

Claim 9

The apparatus of claim 4 including dashpot means for preventing rapid lowering of said irradiated fuel assembly from a raised position, said dashpot means being fixedly connected to said rod member and movably attached to said latching means.

Claim 10

The apparatus of claim 7 wherein said dashpot means comprises at least one elongated tube member serving as a cylinder for travel therein of a piston, said piston being connected by an endless cable to said latching means, said dashpot means being operated by a hydraulic fluid contained within said cylinder and acting on both sides of said piston.

Claim 13

The method of claim 9 including the additional step of activating a dashpot while the fuel assembly is being lifted and supported by both the support and the redundant support.

Claim 14

The method of claim 9 including the additional step of fixedly coupling the fuel assembly to the redundant support when the fuel assembly is fully raised with respect to the supporting apparatus.

Claim 15

The method of claim 11 including the step of lowering the fuel assembly at a predetermined rate of descent which is controlled by the dashpot.

Claim 16

The method of claim 12 including the additional step of disengaging the fuel assembly from the redundant support by lowering the fuel assembly, then ungrasping the fuel assembly from the support when the fuel assembly is fully lowered.