# US 4,374,462 A · Decontamination apparatus

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- Number: US 4,374,462 A
- Document ID: US4374462A
- Status: Granted
- Kind: A
- Application number: 06/063,324
- Filed: 1979-08-02
- Granted: 1983-02-22
- Earliest claimed: 1979-08-02
- Assignees: Westinghouse Electric Corp.
- Inventors: Thaddeus A. Wojcik; Richard M. Kobuck; Ronald F. Antol
- Web page: https://patentgrep.com/patent/US4374462A

## CPC

- F22B 37/003: {Maintenance, repairing or inspecting equipment positioned in or via the headers}
- G21F 9/005: {Decontamination of the surface of objects by ablation}
- F22B: METHODS OF STEAM GENERATION; STEAM BOILERS
- G21F: PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR (radiation protection by pharmaceutical means A61K8/00, A61Q17/04; in cosmonautic vehicles B64G1/54; combined with a reactor G21C11/00; combined with X-ray tubes H01J35/16; combined with X-ray apparatus H05G1/02)

## Abstract

Apparatus for decontaminating radioactive components comprising an attachment mechanism for completely suspending the apparatus from the tube sheet of a nuclear steam generator, a first drive mechanism for moving the apparatus in a first direction, a second drive mechanism for pivoting the apparatus in a second direction, and a third drive mechanism for moving the apparatus in a third independent direction. The apparatus also comprises a dual nozzle arrangement attached to the third drive mechanism for directing a water-grit mixture toward the component to be decontaminated. The apparatus provides a mechanism for remotely decontaminating the channel head of a nuclear steam generator so as to allow working personnel to enter therein.

## Claims

### Claim 1

Decontamination apparatus for decontaminating radioactive nuclear steam generators comprising:
an attachment mechanism attached to a tube sheet of said nuclear steam generator for completely suspending said decontamination apparatus therefrom;
a first support member attached to the under side of said attachment mechanism;
a harmonic first drive mechanism attached to said first support member for rotating said decontamination apparatus in a horizontal plane parallel to said tube sheet;
a harmonic second drive mechanism attached to said first drive mechanism for rotating said decontamination apparatus in a plane substantially perpendicular to the plane of said tube sheet;
a support arm attached to said second drive mechanism;
a nozzle support mounted on said support arm;
at least two nozzles mounted on said nozzle support and arranged at between approximately 30.degree. to 70.degree. from the center line of said support arm;
a chain and sprocket third drive mechanism disposed in said support arm and attached to said nozzle support for moving said nozzle support and said nozzles in a direction along said support arm, said drive mechanisms providing a means of locating said nozzles near the various surfaces of said nuclear steam generator while maintaining said nozzles approximately 6 to 10 inches from said surfaces; and
water-grit supply means connected to said nozzles for supplying a water-grit mixture to said nozzles at a pressure between approximately 200 psi and 2700 psi and with said water grit-mixture having a grit concentration of approximately 3% to 7% by weight, said nozzles directing said water-grit mixture toward the surface of said nuclear steam generator and thus decontaminating said nuclear steam generator.

### Claim 2 (depends on 1)

The apparatus according to claim 1 wherein said nozzles are arranged at approximately 45.degree. from the center line of said support arm.

### Claim 3 (depends on 2)

The apparatus according to claim 2 wherein said apparatus further comprises a suction hose disposed in said nuclear steam generator for removing the contaminated products from said component.

### Claim 4 (depends on 3)

The apparatus according to claim 3 wherein said attachment mechanism comprises a support plate having at least four camlocks disposed herein for supporting said support plate from said tube sheet and having a plurality of guide pins disposed thereon for aligning said support plate with said tube sheet.