Nozzle dam translocating system

• US 4,959,192 A
• Filed: 06/13/1989
• Issued: 09/25/1990
• Est. Priority Date: 06/13/1989
• Status: Expired due to Fees

• Current Assignee: Tennessee Valley Authority (Government of the United States of America)
• Original Assignee: Tennessee Valley Authority (Government of the United States of America)
• Inventors: Jones, William C., Trundle, Mark H.
• Primary Examiner(s): Wasil, Daniel D.
• Application Number:
  US07/365,641
• Time in Patent Office: 469 Days
• Field of Search: 376/260, 376/204, 376/203, 376/277, 376/463, 29/906, 29/723, 29/726, 29/157.4, 29/157 R, 29/157 C, 29/428, 165/71, 165/76, 165/11.2, 138/89, 138/93, 122/379, 220/232, 220/233, 49/477, 49/506, 277/1, 277/135, 254/413, 254/415, 254/389
• US Class Current: 376/260
• CPC Class Codes: F22B 37/003 Maintenance, repairing or inspecting equipment positioned in or via the headers
• CPC Class Codes: F22B 37/222 Nozzle dams introduced through a smaller manway, e.g. foldable
• CPC Class Codes: G21C 13/067 for tubes, e.g. standpipes; Locking devices for plugs
• CPC Class Codes: Y02E 30/30 Nuclear fission reactors
• CPC Class Codes: Y10T 29/53113 Heat exchanger

Abstract

The present invention relates to a system, teaches a technique, and provides apparatus eminently useful for the installation/removal, from a remote and protected location, of nozzle dams onto and from nozzle holddown rings within the channel heads of certain steam generators, including the types typically used in conjunction with the operation of pressurized hot-water nuclear power plants. The technique or method of the instant invention involves methodology for remotely introducing usually with the aid of tackle insertion tool means, through an open channel head manway requisite tubesheet tackle means, or tackle means, as well as strapping means and the securing of same therein; inserting through said open manway, usually with the aid of lifting means, folded nozzle dam means; opening said dam means and properly orientating same relative to said nozzle holddown ring; inserting, orientating, and securing the center portion of said nozzle dam means, torquing bolting means to predetermined limits; and removing from said channel head all said attendant tubesheet tackle means. The effecting of the instant technique requires only a minimal amount of relatively inexpensive, but specially designed equipment and is simply, quickly, and easily placed into practice by, for example, manipulation of same by one or more human operators who are physically located outside said channel head(s) and adjacent said open manway thereby substantially reducing the effective radiation dose heretofore normally associated with such nozzle dam installation and removal.

Claims

1. A nozzle dam translocating system for remotely relocating nozzle dam means from outside the confines of nuclear reactor steam generator channel head means to coupled association with nozzle holddown ring means within the confines of said channel head means and for the converse thereof to thereby substantially minimize personnel exposure to radiation and/or radioactive contamination environment within said channel head means, said system comprising:

(a) nuclear reactor steam generator channel head means having manway means and nozzle holddown ring means provided on the lower wall thereof, and tubesheet means generally defining a horizontal plane comprising the upper boundary thereof;

(b) tubesheet tackle means adapted for remote location and attachment to a first predetermined situs, said first predetermined situs disposed on said tubesheet means;

(c) lifting means adapted for operative association with both said tubesheet tackle means and a second predetermined situs, said second situs located outside the confines of said channel head means;

(d) nozzle dam means adapted in folded mode for introduction through said manway means and into said channel head means;

(f) nozzle dam strapping means adapted for securing to said nozzle dam means either prior or subsequent to introduction thereof through said open manway means and into said channel head means, and further adapted for coupling with said lifting means and said tubesheet tackle means, whereby subsequent actuating of said lifting means elevates said folded nozzle dam means adapted in folded mode to effect the unfolding thereof to the full open position and the continued actuating of said lifting means translocates said fully opened nozzle dam means until the center point thereof is substantially vertically disposed over the center point of said nozzle holddown ring means and in juxtaposition therewith;

(g) remote determination orientation means adapted for inspection and/or adjustment of said nozzle dam means relative to the angular rotation, or the horizontal vector displacement, or both, of said nozzle dam means relative to said nozzle holddown ring means;

(h) bolt starting tool means adapted for remotely securing, at least temporarily, said nozzle dam means and later mentioned nozzle dam center section means, to said nozzle holddown ring means;

(i) nozzle dam center section means adapted for introduction through said manway means and into said channel head means and further adapted for remote operative association with at least a portion of said nozzle dam strapping means whereby coupling of said nozzle dam strapping means with said lifting means and the subsequent actuating thereof effects positioning and engagement of said center section means with said nozzle dam means; and

(j) torquing means adapted for securing said nozzle dam means to said nozzle holddown ring and said nozzle dam center section to said nozzle holddown ring.

2. The nozzle dam translocating system of claim 1 in combination with nozzle dam remote rotation means adapted for engagement with said nozzle dam means and for effecting angularly movement thereof, relative to said nozzle holddown ring means in juxtaposition therewith.

3. The nozzle dam translocating system of claim 1 wherein said first determined situs is generally vertically above about the center point of said nozzle holddown ring means.

4. The nozzle dam translocating system of claim 1 wherein said nozzle dam means is coupled with said lifting means in operative association with tubesheet tackle means attached to said tubesheet at a third situs, said third situs generally located vertically above the center line of said manway means for introducing said nozzle dam means in folded mode through said manway means and into said channel head means.

5. The nozzle dam translocating system of claim 1 in combination with tackle insertion tool means for introduction through said manway means and into said channel head means of said nozzle dam tubesheet tackle means.

6. The nozzle dam translocating system of claim 1 in combination with alignment pin tool means for remotely effecting a determination of the proper orientation of said nozzle dam means in relation to said nozzle holddown ring means.

7. The nozzle dam translocating system of claim 1 in combination with tubesheet mounted video camera means for remotely effecting a determination of the proper orientation of said nozzle dam means in relation to said nozzle holddown ring means.

8. The nozzle dam translocating system of claim 1 in combination with hook pole means for remote operative association of said nozzle dam center section means with at least a portion of said nozzle dam strapping means.

9. The nozzle dam translocating system of claim 1 in combination with hook pole means for remote operative association of said nozzle dam strapping means with said lifting means.