Apparatus for vertically segmenting a boiling water reactor control rod blade
View Patent ↗Apparatus for longitudinally segmenting a cruciform shaped irradiated boiling water reactor control rod having four elongated blades radially extending from a central spline, into four flat panels. The apparatus employs a double bladed band saw with the band saw blades orthogonally oriented at two different elevations and having one side of each band saw blade crossing over the center of the spline of the control rod in between the control rod blades.
1. A tool for making two substantially simultaneous cuts along an elongated length of a spline of a boiling water reactor cruciform shaped control rod having four elongated panels radially extending at spaced locations around a circumference of the spline, with each of the panels having two oppositely facing sides and the spline having a central axis extending along the elongated length, the tool comprising:
a tool base plate oriented in a substantially horizontal position, substantially perpendicular to the central axis when the control rod is in position to be cut, and the tool base plate is configured to be moved vertically;
a first pair of spaced pulley wheels rotatably supported from one side of the tool base plate with one of the first pair of spaced pulley wheels comprising a drive wheel that is operatively connected to a motor to rotate the drive wheel when the motor is in an on state and a second of the first pair of spaced pulley wheels oriented along a first axis extending between the drive wheel and the second of the first pair of spaced pulley wheels;
a first band saw blade having a first set of teeth facing in a downward direction, extending around the drive wheel and the second of the first pair of spaced pulley wheels wherein a first side of the first band saw blade extends between the drive wheel and the second of the first pair of spaced pulley wheels and around the second of the first pair of spaced pulley wheels and a second side of the first band saw blade extends between the second of the first pair of spaced pulley wheels and the drive wheel and around the drive wheel wherein the first side of the first band saw blade extends over a first opening in the tool base plate that is sized for the boiling water reactor control rod to axially pass through in a direction of the central axis and the first band saw travels in a first plane, around the drive wheel and the second of the first pair of spaced pulley wheels, substantially parallel to the one side of the tool base plate when the motor is in the on state;
a second pair of spaced pulley wheels rotatably supported from the one side of the tool base plate with one of the second pair of spaced pulley wheels comprising a follower wheel that is operatively connected to the drive wheel to rotate the follower wheel when the motor is in an on state and a second of the second pair of spaced pulley wheels oriented along a second axis extending between the follower wheel and the second of the second pair of spaced pulley wheels, the second axis being oriented at a fixed angle greater or less than zero relative to the first axis; and
a second band saw blade having a second set of teeth facing in the downward direction, extending around the follower wheel and the second of the second pair of spaced pulley wheels wherein a first side of the second band saw blade extends between the follower wheel and the second of the second pair of spaced pulley wheels and around the second of the second pair of spaced pulley wheels and a second side of the second band saw blade extends between the second of the second pair of spaced pulley wheels and around the follower wheel wherein the first side of the second band saw blade extends over the first opening in the tool base plate that is sized for the boiling water reactor control rod to pass through and the second band saw travels in a second plane, around the follower wheel and the second of the second pair of spaced pulley wheels, substantially parallel to the first plane, when the motor is in the on state.
2. The tool of claim 1 wherein the follower wheel is connected to the drive wheel with a chain and sprocket coupling.
3. The tool of claim 1 wherein the drive wheel and the follower wheel respectively drive the first and second band saw blades at approximately the same speed.
4. The tool of claim 1 wherein the first side of the first band saw blade and the first side of the second band saw blade cross one another over the central axis when the boiling water reactor control rod is positioned in the first opening in the tool base plate.
5. The tool of claim 1 wherein the opening in the tool base plate includes guide supports extending from the tool base plate to contact, ride along and guide each side of the panels through the first opening in the tool base plate when the boiling water reactor control rod panels extend through the opening.
6. The tool of claim 5 wherein the guide supports on either side of each panel are supported about the first opening at a different elevation relative to the central axis.
7. The tool of claim 6 wherein the different elevations are approximately 50 mm apart.
8. The tool of claim 6 wherein the guide supports extend above and below the tool base plate.
9. The tool of claim 1 wherein the tool base plate includes a second opening through which a guide pole can extend to guide movement of the tool base plate in a direction parallel to the central axis when the boiling water reactor control rod panels extend through the first opening.
10. The tool of claim 9 including means for moving the tool base plate along a direction parallel to the central axis.
11. The tool of claim 10 wherein the means for moving the tool base plate is an overhead hoist.
12. The tool of claim 9 including the guide pole and means for supporting the guide pole on a bottom of a spent fuel pool.
13. The tool of claim 9 wherein the guide pole is a guide rail configured to be supported from a reactor building floor with the guide rail extending down into a spent fuel pool.
14. The tool of claim 13 wherein the guide rail is configured to extends down into the spent fuel pool at least six meters.
15. The tool of claim 1 wherein the first and second band saw blades operate to substantially simultaneously cut the boiling water reactor control rod vertically along the spline dividing the boiling water reactor control rod spline into four substantially equal sections.
16. The tool of claim 1 wherein when in an upper position above the boiling water reactor control rod the tool can be rotated 180 degrees to facilitate maintenance.
17. The tool of claim 1 wherein the motor is a hydraulic motor.
18. The tool of claim 1 including a camera on the tool base plate for managing the cutting process.
19. The tool of claim 18 wherein the camera includes a plurality of cameras.
20. The tool of claim 1 wherein the fixed angle is approximately ninety degrees.