US 5,042,861 AGranted

Nozzle dam remote installation system and technique

AssigneeTennessee Valley Authority

InventorsMark H. Trundle, William C. Jones

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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 means. The effecting of the instant technique requires only a minimal amount of relatively inexpensive, but specifically 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.

Claims5

Dependent claims

A device for remote operative association with a tube gripper, said tube gripper predisposed for cooperatively engaging a plurality of tubes of substantially equal inner diameters and including plate means and sleeve attachment means, said device comprising:

(a) shaft means having a first end and a second end;
(b) connecting means traversing said shaft means substantially from said first end to said second end;
(c) actuating means disposed near said first end of said shaft means and operatively associated with said connecting means;
(d) first engaging means disposed near said second end of said shaft means and generally comprising a U-shaped member having one leg thereof substantially longer than the other, each of said legs comprising a plate member, the major planes of which are, in the intended mode of operation of said device, generally horizontal, with the bottommost plate member being the substantially longer leg and having a generally triangular-shaped opening therein, the base of said triangular-shaped opening being juxtaposed the edge of said lower plate member which is most remote from the U-portion of said first engaging means, the apex of said generally triangular-shaped opening terminating at a distance away from said U-portion approximately equal to the length of said shorter leg, and said plate members separated, one from the other, a distance greater than the thickness of said plate means for the accommodation into said U-portion and on said bottommost plate member of said plate means;
and
(e) second engaging means juxtaposed said first engaging means and generally disposed vertically thereabove for operative association with both said sleeve attachment means and said connecting means.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/511,120Filed 19 Apr 1990 · division
Priority: 13 Jun 1989
Granted: 27 Aug 1991
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

G21C 13/067
Sealing-plugs: for tubes, e.g. standpipes; Locking devices for plugs
F22B 37/003
Specially adapted for nuclear steam generators, e.g. maintenance, repairing or inspecting equipment not otherwise provided for: maintenance,…
F22B 37/222
Covers for drums, collectors, manholes or the like: nozzle dams introduced through a smaller manway, e.g. foldable
Y02E 30/30
Energy generation of nuclear origin: nuclear fission reactors