Improving underwater thermal cutting techniques and associated remote-control systems

Directorate-General For Research And Innovation European Commission

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Nuclear energy and safety

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• Publié par: DIRECTORATE-GENERAL-FOR-RESEARCH-AND-INNOVATION-EUROPEAN-COMMISSION
• Nombre de lectures: 21
• Langue: English
• Poids de l'ouvrage: 16 Mo

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ISSN 1018-5593
European Commission
nuclear science
and technology
Improving underwater thermal cutting
techniques and associated
remote-control systems European Commission
nuclear science
and technology
Improving underwater thermal cutting
techniques and associated
remote-control systems
J. P. Dufayet - CEA, Centre d'Études de Cadarache
F.-W. Bach / U. Priesmeyer - Institut für Werkstoffkunde, Universität Hannover
P. Drews / U. Strunz - Prozeßsteuerung in der Schweißtechnik, Aachen
G. Pilot - CEA, Centre d'Études de Saclay
Contract No FI2D-CT 90-0019
This work was performed in the framework of the European Atomic Energy Community's
research programme on the decommissioning of nuclear installations (1989-93),
Area A3 'Dismantling techniques'
Directorate-General
Science, Research and Development
1995 EUR 16607 EN LEGAL NOTICE
Neither the European Commission nor any person acting on
behalf of the Commission is responsible for the use whicn might be made of the
following information
Cataloguing data can be found at the end of this publication
Luxembourg: Office for Official Publications of the European Communities, 1995
ISBN 92-827-5084-1
© ECSC-EC-EAEC, Brussels · Luxembourg, 1995
Reproduction is authorized, except for commercial purposes, provided the source is acknowledged
Printed in Luxembourg CONTENTS
ABSTRACT 1
1 OBJECTIVES AND SCOPE 2
2 CONTRACTUAL WORK PROGRAMME
3 DESCRIPTION OF THE REPRESENTATIVE MODELS TO BE CUT DURING THE 3
TESTS
4 HANDLING SYSTEM AND CONTROL SYSTEM FOR SENSOR CONTROLLED 3
PILOTING
4.1 Handling system 3
4.2 Control system 6
5 MAIN RESULTS OBTAINED ON THE DEVELOPMENT OF THE PLASMA TORCH 7
IN CADARACHE
6 MAIN RESULTS OBTAINED ON THE DEVELOPMENT OF THE TOOLS FROM IW 8
LABORATORY
7 COMPARATIVE TESTS AT CADARACHE 10
7.1 Overall description of the installation
7.2 Preliminary tests 12
7.3 Comparative tests on non-radioactive and radioactive test pieces4
7.4 Analysis of the secondary emissions
8 COMPLEMENTARY TESTS WITH THE ENTIRE INSTALLATION TRANSPORTED 18
TO AACHEN
9 CONCLUSION 18
ANNEX
Al DEVELOPMENT OF THE PLASMA TORCH IN CADARACHE 19
A2T OF THE TOOLS FROM IW LABORATORY 26
A3T OF THE CONTROL SYSTEM 47
A4 ANALYSIS OF THE SECONDARY EMISSIONS DURING THE TESTS AT 62
CADARACHE
III ABSTRACT
This study is chiefly focused on cutting tests made on thick steel plates by means of four
different thermal tools: the plasma torch, the plasma saw, contact arc metal cutting and
the consumable electrode. The tests were performed on the one hand on non-radioactive
samples (stainless steel plates, models representing reactor parts) with a maximum
thickness of 200 mm, and on the other hand, on radioactive parts from the G2 reactor at
Marcoule.
Comparative measurements were made on the secondary emissions (solid wastes, gases)
in the Pegase facility at the Cadarache research centre. A further investigation was carried
out for the radioactive parts to determine the distribution of Co-60 in the solid wastes.
The tool holder and manipulator were equipped with a sensor-controlled automatic drive
system. 1 OBJECTIVES AND SCOPE
This project aimed to improve underwater thermal cutting techniques, such as the plasma
torch, the consumable electrode tool, the plasma saw, the contact arc metal cutting tool, and
their remote control systems. The main objectives were to cut greater thicknesses and to
improve operation safety, e.g., assess harmful waste-products, protect workers, assist the
operator during operation. This work was carried out in close cooperation between CEA
Cadarache, Institut fur Werkstoffkunde Hannover, RWTH Aachen, and CEA Saclay. The
objectives of the project were to achieve cutting up to a thickness of 200 mm. The work
involved an experimental investigation in the laboratory of each contractor, followed by real-
case applications under radioactive and non-radioactive conditions in the Pégase facility at
Cadarache.
2 CONTRACTUAL WORK PROGRAMME
2.1 Development of the Plasma Torch and Adaptation of the Driving Device
(CEA Cadarache)
This step included : 1) Improvement of torch performance with a view to achieving underwater
cutting thicknesses of up to 150 mm ; 2) Adaptation of the driving systems and tools for
cutting in a water depth up to 2 m in relation to the installation of inductive sensors for tool
piloting.
2.2 Development of Other Tools (I.W. Hanover)
The three following tools had to be developed and improved with a view to achieve cutting
tools for thicknesses of up to 200 mm : the plasma saw, the consumable electrode tool, contact
arc metal cutting (CAMC). Cutting on models had to be performed with these tools. The
secondary emissions had also to be measured (aerosols, hydrosols, and sedimented dross) in
order to compare them with the measurements taken with plasma torch cutting at Cadarache.
2.3 Development of Control Systems for Sensor-Controlled Piloting of the Handling Systems
for the Tools and the Process Parameters (APS Aachen)
This work included the development of systems for piloting the handling system, process
control and tool handling during cutting, taking into account cutting parameters.
2.4 Final Tests at Cadarache
Comparative cutting tests had to be performed at Cadarache in the Pégase facility with the
different laboratory-developed tools. These tests included cutting non-radioactive test pieces
with an analysis of the secondary solid and gaseous emissions, and cutting radioactive samples
from a nuclear facility.
2.5 Final Evaluation and Recommendations
These tasks include a conclusive assessment of the processed results with recommendations for
their application to a large-scale decommissioning operation. 3 DESCRIPTION OF THE REPRESENTATIVE MODELS TO BE CUT DURING THE
TESTS
These models came from the Rapsodie reactor which is in its decommissioning phase and were
chosen in relation to ordinary parts of the reactor as well as singular parts (Figure 1). The
models are numbered from 2 to 6.
4 HANDLING SYSTEM AND CONTROL SYSTEM FOR SENSOR-CONTROLLED
PILOTING
4.1 Handling System
In order to cut the testpieces and other parts as defined in our work programme, it was
necessary to specially build a tool holding device as well as a water tank. The specifications of
this manipulator were chosen so as to meet the cutting conditions for the various tools
implemented : plasma torch, consumable electrode, plasma saw, CAMC.
The main features of the manipulator are given in Table I.
TABLE I : Main Features of the Manipulator
X Y Ζ θ
Tool
displacement : 1000 800 1000 360
mm and degree
Manipulator
speed : mm/min 0 to 400 0 to 400 0 to 400
rpm Oto 25
The manipulator and the tank are shown in the Figures 2, 3, 4, and 5. FIGURE. 1 : Definition of lhe models from the Rapsodie Reactor.