Systems and methods of remote control rod drive decoupling

Patent metadata

Field	Value
Publication number	US-9767932-B2
Application number	US-201414337378-A
Country	US
Kind code	B2
Filing date	Jul 22, 2014
Priority date	Jul 22, 2014
Publication date	Sep 19, 2017
Grant date	Sep 19, 2017

Abstract

Systems join with a control rod drive and expand or contract to displace elements necessary for decoupling. Joining structures affix to on sides of the control rod drive allow discriminatory jacking by a powered drive also in contact with the control rod drive. A moveable piston tube can be displaced by this jacking with hundreds or thousands of pounds of force with respect to the control rod drive. Probes and other instrumentation and sensors are useable in the systems to accurately measure any of piston tube displacement, temperature, malfunction; drive power status, displacement or speed; and communications status. Manual interaction with the systems are not required during the jacking, and installation and removal of the systems requires no tools or great amount of time or effort. Through remote operation and brief installation, human exposure to radiation about control rod drives is minimized.

First claim

What is claimed is:

1. A remote decoupling system for use in a nuclear reactor, the system comprising:
an attachment structure configured to removably secure to a control rod drive of the reactor such that the control rod drive and attachment structure do not move relative to one another in a vertical direction;
wherein the attachment structure includes,
a sleeve shaped to fit around a lower flange of the control rod drive, and
a clamp arm connecting to the sleeve and configured to attach to a backside of the flange; and
a jack secured to the attachment structure, wherein the jack is configured to displace a piston tube of the control rod drive in the vertical direction relative to the control rod drive and the attachment structure without human contact.

2. The system of claim 1 , wherein the jack includes a port configured to mechanical secure to a probe inserted in the piston tube, and to provide electrical communications and electrical power to the probe.

3. The system of claim 1 , wherein the clamp arm is rotatable with respect to the sleeve and extendable, and wherein the clamp arm includes a lock that prevents further rotation and extension of the clamp arm.

4. The system of claim 1 , wherein the jack includes an electric motor configured to displace the jack and the piston tube with approximately 1000 pounds of force.

5. The system of claim 1 , wherein the jack includes a communications port configured to receive signals to control the operation of the jack and transmit information about operation of the jack.

6. The system of claim 1 , wherein the attachment structure is removably joined to the jack.

7. The system of claim 6 , wherein the attachment structure is removably joined to the jack by structures requiring only human hands to join and remove.

8. The system of claim 7 , wherein the structures are locks having variable edges that slide within the jack between positions that capture the attachment structure and positions that do not capture the attachment structure.

9. The system of claim 1 , further comprising:
a battery powering the jack.

10. The system of claim 1 , wherein the attachment structure includes,
two clamp arms that each includes a curved end configured to bias against a flange of the control rod drive, wherein each clamp arm includes an extendable and rotatable locking edge having a variable diameter, wherein the locking edge is separated from the curved end,
a cylindrical sleeve configured to fit over a lower portion of the flange while leaving the piston tube at the end of the flange open, wherein the cylindrical sleeve includes two ears opposite each other, and wherein each one of the clamp arms connects to a corresponding one of the ears via a hinge.

11. The system of claim 10 , wherein the clamp arm is configured to rotate about the hinge to fit over the flange and secure to the flange, and wherein each ear includes a notch into which the locking edge may be extended and rotated such that the clamp arms cannot be extended or rotated about the hinges when each locking edge is rotated into its corresponding notch.

12. The system of claim 1 , further comprising:
a transmitter configured to transmit information from the sensors to a remote operator.

13. The system of claim 12 , wherein the jack includes, a motor configured to displace the jack in the vertical direction with a force sufficient to also displace the piston tube attached to the jack in the vertical direction, wherein the transmitter is further configured to transmit information of operation of the motor and the displacement to the remote operator.

14. The system of claim 13 , wherein the jack further includes a battery that powers the motor and the transmitter.

15. The system of claim 14 , further comprising:
a receiver configured to receive operational signals from the remote operator, and wherein the motor is configured to displace the jack based on the operational signals.

16. The system of claim 1 , wherein,
the control rod drive extends from reactor pressure vessel of the nuclear reactor to a flange, wherein the flange is cylindrical and has an upper portion and a lower portion, wherein the upper portion has a larger diameter than the lower portion,
the piston tube extends a length of the control rod drive through a center of the upper portion and the lower portion of the flange, and
the attachment structure includes,
a tubular sleeve shaped to sit on the lower portion of the flange and having a diameter smaller than the upper portion of the flange,
a first sleeve wing including a first hinge and a second sleeve wing including a second hinge,
a first clamp arm joined to the first sleeve wing via the first hinge such that the first clamp arm is rotatable in a single plane with respect to the tubular sleeve, wherein the first clamp arm has a U-shaped end that is rotatable behind the upper portion of the flange when the tubular sleeve is seated on the lower portion of the flange, and
a second clamp arm joined to the second sleeve wing via the second hinge such that the second clamp arm is rotatable in a single plane with respect to the tubular sleeve, wherein the second clamp arm has a U-shaped end that is rotatable behind the upper portion of the flange when the tubular sleeve is seated on the lower portion of the flange.

17. The system of claim 16 , wherein,
the first sleeve wing includes a first notch,
the first clamp arm includes a first rotatable and extendable locking edge that rotates into the first notch when the first clamp arm and the second clamp arm are parallel, and
the second clamp arm includes a second rotatable and extendable locking edge that rotates into the second notch when the first clamp arm and the second clamp arm are parallel, wherein the first and the second locking edges being rotated into the first and the second notches prevents all relative movement among the first clamp arm, the second clamp arm, and the tubular sleeve except for further rotation of the first and the second locking edges.

18. The system of claim 17 , wherein the jack includes,
a first locking receptacle configured to receive and lock to the first clamp arm when the first clamp arm and the second clamp arm are parallel,
a second locking receptacle configured to receive and lock to the second clamp arm when the first clamp arm and the second clamp arm are parallel, wherein the first and the second clamp arms being locked into the first and the second receptacles prevents all relative movement among the jack and the attachment structure, except for further rotation of the first and the second locking edges.

19. A remote decoupling system for use in a nuclear reactor having a control rod drive extending from the nuclear reactor, the control rod drive having a flange exterior to and separated from the reactor, the control rod drive having a central piston tube extending inside the control rod drive, the system comprising:
an attachment structure including a tubular sleeve and a plurality of clamp arms rotatably joined to the tubular sleeve, wherein the tubular sleeve is shaped seat onto a first side of the flange, wherein the plurality of clamp arms are shaped to clamp to a second side of the flange, wherein the first side and the second side of the flange are opposite of each other, wherein the tubular sleeve being seated and the clamp arms being clamped removably secures the attachment structure to the control rod drive such that the control rod drive and attachment structure do not move relative to one another in a vertical

Assignees

• Ge Hitachi Nuclear Energy Americas Llc

Inventors

• Runkle Gary A
• Cole Kenneth M
• Tyson Eli J
• Setliff Harold R
• Suek Steven L
• Swan Martin R

Classifications

• G21C19/207

  Assembling, maintenance or repair of reactor components (G21C3/334 takes precedence) · CPC title

• Y02E30/39

  Cross-Sectional Technologies · mapped topic

• G21C19/105

  with grasping or spreading coupling elements · CPC title

• G21C19/10 Primary

  Lifting devices or pulling devices adapted for co-operation with fuel elements or with control elements (manipulators B25J) · CPC title

• G21C7/12

  Means for moving control elements to desired position (dropping rods in an emergency G21C9/02) · CPC title