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UNDERWATER THERMAL CUTTING TECHNIQUES AND ASSOCIATED REMOTE-CONTROLLED MANIPULATOR SYSTEMS

Objective

This project aims at improving underwater thermal cutting techniques and their remote control. The main objectives are to cut greater thicknesses and improve the safety of operation, eg, assess harmful by-products, protect workers, assist the operator during operations.

So far, underwater thermal cutting of steel has been achieved up to 70 mm thickness. This project has the objective of achieving cutting up to 200 mm. Sensors and associated systems studied in laboratory will be applied in a semi-industrial installation.

The work involves an experimental investigation in the laboratory of each contractor followed by real-case applications under non-radioactive and radioactive conditions in the former Pegase reactor in Cadarache.

The project is a follow-up of work performed in the 1984-88 EC programme (contracts FI1D0037, 0007 and 0039).
This project aims at improving underwater thermal cutting techniques and their remote control. The main objectives are to cut greater thickness and improve the safety of operation, eg assess harmful by products, protect workers, assist the opertor during operation.

The facilities such as the moving device and test tank have been studied, realized and installed in accordance with the requirements necessary to cut great thicknesses. The modification of the current nuclearized torch is being made. A 1000A torch and a cooling system have been ordered. The problem of supplying the torch with high voltage and current was analyzed. Tests on the plasma torch plasma saw and the cutting process have been made in order to qualify working parameters. Then different material thicknesses were cut with a consumable electrode tool using stainless steel wire. The driving device for the movement of the plasma saw was completed and tested. As regards the control system for the given application, the inductive sensor was defined to satisfy:
accuracy;
ability for process control;
resistance to water and dirt;
small dimensions;
shielding against electrical and mechanical influences;
functions for stainless steel materials.
The development of a hole and edge detection algorithm and the specification for the microprocessor control unit have been made. Software modules have been specified and partly implemented. Research has continued to find samples for radioactive sample testing.
WORK PROGRAMME

1. Preliminary tasks (CEA-Cad)

1.1. Detailed requirements and objectives of the project
1.2. List of parameters and ranges to be studied
1.3. Specifications of sub-systems

2. Development of the plasma torch and adaptation of the moving device (CEA-Cad)

2.1. Improvement of the performances of the plasma torch
2.2. Adaptation of the moving device
2.3. Integration of the sensors into the torch handling system
2.4. Cutting tests with measurement of effluents

3. Development of other tools (UH-IW)

3.1. Optimization of cutting parameters of plasma saw and consumable electrode
3.2. Control systems usable with the manipulator of CEA-Cad
3.3. Cutting tests with measurement of effluents

4. Development of control systems for sensor-controlled piloting of the handling system for the tools and the process parameters (RWTHA)

4.1. Improvement and application of inductive sensors
4.2. Process control and piloting of the tool handling system
4.3. Interfacing between the sensor system and the handling control system
4.4. Function testing in the laboratory

5. Preparation of radioactive samples taken from nuclear installations (all)

6. Final tests in Cadarache (all)

6.1. Transport of the systems to Cadarache and installation on the manipulator
6.2. Cutting tests on nonradioactive representative models
6.3. Tests with samples prepared under B.5.

7. Final evaluation and recommendations (all)

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Commissariat à l'Energie Atomique (CEA)
Address
Centre D'études De Cadarache Sere-ders
13113 Saint-paul-lez-durance
France

Participants (3)

AACHEN UNIVERSITY OF TECHNOLOGY
Germany
Address
Templergraben 55
52056 Aachen
Commissariat à l'Energie Atomique (CEA)
France
Address
Centre D'études De Saclay
91191 Gif-sur-yvette
UNIVERSITAET HANNOVER
Germany
Address
Appelstrasse 11A
30167 Hannover