D. Maisonnier

Development of a long reach articulated manipulator for ITER in vessel inspection under vacuum and temperature

This project takes place in the EFDA Remote Handling (RH) activities for the fusion reactor International Thermonuclear Experimental Reactor (ITER). The aim of the R&D program is to demonstrate the feasibility of in-vessel RH intervention by a long reach, limited payload manipulator which penetrates the first wall using the six IVVS penetrations. Potential activities for this device include close inspection of the plasma facing surfaces and leak detection. The work includes the design, manufacture and testing of a demonstrator articulated manipulator called the In-Vessel Penetrator (IVP). The first part of this work concerned the analysis of the requirements and resulted in the development of the conceptual design of the overall manipulator, comprising a 5 module, 11 d.o.f robot based on a parallelogram structure. A scale one mock up of a representative segment was manufactured and tested. In parallel, a feasibility study of the IVP operation was made and provided recommendations to modify the design for intervention under vacuum and temperature. Some technologies were selected and analysed to determine their suitability to the IVP application and items identified for further validation. This paper presents the whole robot concept, the results of the test campaign on the prototype demonstrator and the vacuum and temperature technologies study.

ITER in-vessel components transfer using remotely controlled casks

The paper provides an overview of the ITER transfer cask system design. The system is required during the assembly and maintenance periods of ITER. The system is designed with safety as the primary goal, to ensure minimum exposure risk to personnel and to allow the reliable transfer of components between the machine and the hot cell.

Remote Maintenance of In-Vessel Components for ITER

ITER in-vessel components must be remotely maintained due to neutron activation. Components that require maintenance include the blanket shield modules, divertor cassettes and ancillary systems mounted in the vacuum vessel (VV) ports. Maintenance is predominantly accomplished by component removal and transfer to the hot cell facility for repair or waste processing. Component transfer between the VV and the hot cell is performed in sealed casks that dock to the VV ports. An overview of the in-vessel remote maintenance requirements, techniques and equipment is presented.

Carrier and bore tools for 4 in. bent pipes

Following the ALARA principle, remote handling techniques are developed for ITER maintenance to prevent direct hands-on access on the vacuum vessel components and reduce the personal dose rate. Maintenance of the divertor cassettes will require cutting, welding and non-destructive testing of the water-cooling-pipes. Work performed under the EFDA work program aimed to demonstrate the feasibility to operate with bore tools by means of an innovative carrier concept and to study the associated mechanisms. This paper presents a carrier designed to navigate through 4 in. bent pipes and the results of the test campaigns on the prototypes.

Viewing and Inspection in Tokamak Machines

This paper describes solutions adopted for viewing inside the vessel of present day tokamak machines. Concepts capable of satisfying the viewing and inspection requirements for a next step machine are outlined, together with the supporting R&D currently in progress. The inspection requirements are also briefly discussed from the licensing standpoint.

Overview of Bore Tools Systems for divertor remote maintenance of ITER

Because of the radiation levels preventing direct, hands-on access to the machine components, maintenance work on ITER will eventually require the use of Remote Handling techniques. In particular, the replacement of components such as divertor and blanket modules will require the use of remote cutting, welding and Non Destructive Testing of water cooling pipes.

Remote handling technology development for fusion experimental reactors

Abstract Fusion experimental reactors are a major step toward realization of fusion energy production by commerical reactors. The key objective is to demonstrate the scientific and technological feasibility prior to the demo fusion reactors. The ITER (international thermonuclear experimental reactor) is an experimental reactor and the engineering design has been initiated by the united efforts of the USA, EC, RF, and Japan after completion of the conceptual design activity. Since the reactor core components are activated by the D–T operation, advanced remote handling technologies are inevitably required for assembly and maintenance of the components under the radiation conditions. The key issues to be developed for the remote handling system are radiation hardening over 10 7 R h −1 , precise position—posture control for handling heavy components without the interference in a limited reactor space, and tools for connection—disconnection and inspection. For this purpose, extensive technology developments in parallel with the engineering design are being conducted domestically and internationally through the ITER framework. This paper outlines both an overview of the remote handling system required for fusion experimental reactors and the recent status of remote handling technology development being conducted in Japan, EC and USA.

Dynamic simulation of a planar flexible boom for tokamak in-vessel operations

Abstract In this paper we present a dynamic model for the analysis of the vibrations of planar articulated flexible boom to be used for tokamak in-vessel maintenance operations. The peculiarity of the mechanical structure of the boom enables us to consider separately the oscillations in the horizontal and vertical planes so that two separate models can be constructed for describing these phenomena. The results of simulations based on booms like that proposed for NET in-vessel operations are presented.

Synthetic viewing: comprehensive work representation, making remote work clearer to the operator

Abstract Maintenance work in fusion plants such as the ITER plant will be carried out fully remotely, without any direct view on to the work scene. The basic sources of information about the state of the work are video monitors. In a first development step, this viewing channel was enhanced by three-dimensional computer graphics controlled by signals of motion sensors (such as joint angle sensors) of the real maintenance devices. However, experience has shown that more information is required about the status of all pieces of equipment involved and about the status of the entire handling task, if the work is to be done properly. Viewing for remote handling applications needs to include the display of such status information in a suitable form. Of special importance in this sense is the representation of the work procedures on the computer display, enabling the operator to grasp at a glance the actual state of the work and the details about the subtask to be executed next. The tool providing this “synthetic” viewing but also task-suited to planning, training and controlling support for the operator is the remote handling workstation. The prototype of a remote handling workstation was successfully used in the first complete Karlsruhe experiment for in-torus handling.

Fasteners for structural bolted joints to be assembled in remote handling

Abstract Fasteners are generally considered a matter of a mature technology with a variety of solutions ready to meet a wide range of applications, but their use in remote handling needs accurate considerations. The fastening system has a substantial effect on the total time to perform maintenance operations, and therefore care should be taken from the beginning of the project to its standardization. The set of requirements to be satisfied by a qualification activity on fasteners to be remotely handled within the environmental conditions relevant to the NET—ITER machine (high temperature, radiation, vacuum, cryogenic temperature) deals with shape and dimensions, materials properties, surface finish of mating parts, lubricant compatibility, precautions against galling and seizure, provisions of remedial actions from an emergency situation, fabrication process specification, methods of preload application and control of its persistence under machine operation. The qualification of high strength bolts at cryogenic temperature (4 K) and relevant fracture mechanics tests, and the qualification of suitable coatings and lubricants has been extensively investigated on both specimens and full size components. In this paper we report final results of a three-year development programme on fastener technology.