Inspection Arm Research Articles

Development of an ITER relevant inspection robot

Robotic operations are one of the major maintenance challenges for ITER and future fusion reactors. In particular, in-vessel inspection operations without loss of conditioning will be mandatory. In this context, an Articulated Inspection Arm (AIA) is currently developed by the CEA within the European work programme framework, which aims at demonstrating the feasibility of a multi-purpose in-vessel Remote Handling inspection system using a long reach, limited payload carrier (up to 10 kg). It is composed of 5 segments with 8 degrees of freedom and a total range of 8 m. The first in situ tests will take place by the end of 2007 on the Tore Supra Tokamak at Cadarache (France). They will validate concepts for operations under ITER relevant vacuum and temperature conditions. After qualification, the arm will constitute a promising tool for various applications. Several processes are already considered for ITER maintenance and will be demonstrated on the AIA robot carrier: • The first embedded process is the viewing system. It is already manufactured and will allow close visual inspection of the complex Plasma Facing Components (PFC) (limiters, neutralisers, RF antenna, diagnostic windows, etc.). • In situ localisation of water leakage based on a helium sniffing system is also being studied to improve and facilitate maintenance operations. • Finally a laser ablation system for PFC detritiation, developed in CEA laboratories, is being fitted to be implemented on the robot for future operation in Tore Supra. This paper deals with the integration of the robot into Tore Supra and the progress in the development of the processes listed above. It also describes the current test campaign aiming to qualify the robot performance and reliability under vacuum and temperature conditions.

Development of an inspection robot under iter relevant vacuum and temperature conditions

Robotic operations are one of the major maintenance challenges for ITER and future fusion reactors.In vessel inspection operations without loss of conditioning could be very mandatory.Within this framework, the aim of the Articulated Inspection Arm (AIA) project is to demonstrate the feasibility of a multi-purpose in-vessel Remote Handling inspection system.It is a long reach, composed of 5 segments with in all 8 degrees of freedom, limited payload carrier (up to 10kg) and a total range of 8m.The project is currently developed by the CEA within the European work program. Some tests will validate chosen concepts for operations under ITER relevant vacuum and temperature conditions. The presence of magnetic fields, radiation and neutron beams will not be considered.This paper deals with the choices of the materials to minimize the out-gassing under vacuum and high temperature during conditioning, the implantation of the electronics which are enclosed in boxes with special gaskets, the design of the first embedded process which is a viewing system.

ITER articulated inspection arm (AIA): R&d progress on vacuum and temperature technology for remote handling

This paper is part of the remote handling (RH) activities for the future fusion reactor ITER. The aim of the R&D program performed under the European Fusion Development Agreement (EFDA) work program is to demonstrate the feasibility of close inspection tasks such as viewing or leak testing of the Divertor cassettes and the Vacuum Vessel (VV) first wall of ITER. It is assumed that a long reach, limited payload carrier penetrates the ITER chamber through the openings evenly distributed around the machine such as In-Vessel Viewing System (IVVS) access or through upper port plugs. To perform an intervention a short time after plasma shut down, the operation of the robot should be realised under ITER conditioning i.e. under high vacuum and temperature conditions (120 °C). The feasibility analysis drove the design of the so-called articulated inspection arm (AIA) which is a 8.2 m long robot made of five modules with a 11 actuated joints kinematics. A single module prototype was designed in detail and manufactured to be tested under ITER realistic conditions at CEA-Cadarache test facility. As well as demonstrating the potential for the application of an AIA type device in ITER, this program is also dedicated to explore the necessary robotic technologies required to ITER's IVVS deployment system. This paper presents the whole AIA robot concept, the first results of the test campaign on the prototype vacuum and temperature demonstrator module.

ITER Articulated Inspection Arm (AIA): Geometric calibration issues of a long-reach flexible robot

This paper is part of the Remote Handling (RH) activities for the future fusion reactor ITER. Specifically it relates to the possibility to carry out close inspection tasks of the Vacuum Vessel first wall using a long reach robot called the “Articulated Inspection Arm” (AIA). Early studies for this device identified the need of improving the accuracy of the end-effector position in such robot structures. Therefore, the aim of this R&D program performed under the European Fusion Development Agreement (EFDA) work program is to develop a flexible parametric model with localised compliances of an AIA-like system, in order to compensate for its flexibilities. The geometric calibration is performed using a non-linear multivariable optimisation technique, which minimizes the average error between the simulated and real robot position. The optimised set of parameters, tested on the first segment of the robot, enables to divide by 3 the error on the end-effector position, in comparison to a rigid model. We expect better prediction after mechanical improvements to reduce the serious backlash in the joints. The prediction model applied to the whole arm will enable errors to be reduced from more than 1 m, in some configurations, to a final accuracy of a few centimetres.

Remote maintenance of in-vessel components in Tokamak Fusion Test Reactor

The Tokamak Fusion Test Reactor (TFTR) will generate a total of 3 × 10 21 neutrons during its planned D-T operational period. A maintenance manipulator has been designed and tested to minimize personnel radiation during in-vessel maintenance activities. Its functions include visual inspection, first-wall tile replacement, cleaning, diagnostics calibrations and leak detection. To meet these objectives, the TFTR maintenance manipulator is required to be operable in the TFTR high vacuum environment, typically < 1 × 10 −8 torr, (< 10 −6 Pa). Geometrically, the manipulator must extend 180° either direction around the torus to assure complete coverage of the vessel first-wall. The manipulator consists of a movable carriage assembly, a non-articulated link section mounted on the carriage, and six movable articulated link sections which are driven by electrical actuators. The boom has vertical load capacity of 455 kg and lateral load capacity of 46 kg. The boom can either be outfitted with a general inspection arm or dexterous slave arms. The general inspection arm is designed to hold the leak detector and an inspection camera; it is capable of rotation along two axes and has a linkage system which permits motion normal to the vacuum vessel wall. All systems except the dexterous slave arms are operable in a vacuum.

The TFTR maintenance manipulator

Abstract TFTR plans to begin D—T experiments in mid 1990. The D—T experimental program will produce approximately one hundred shots, with a neutron generation rate of 10 19 neutrons per shot. This will result in high levels of activation in TFTR, especially in the vacuum vessel. The primary purpose of the Maintenance Manipulator is to provide a means of remotely performing certain defined maintenance and inspection tasks inside the vacuum torus so as to minimize personnel exposure to radiation. The manipulator consists of a six-link folding boom connected to a fixed boom on a movable carriage. The entire manipulator is housed in a vacuum antechamber connected to the vacuum torus, through a port formerly used for a vacuum pumping duct. The configuration extends 180° in either direction to provide complete coverage of the torus. The four 3500 1/s turbopumps which were formerly used in the pumping duct will be mounted on the antechamber. The manipulator will utilize two end effectors. The first, called a General Inspection Arm (GIA) provides a moveable platform to an inspection camera and an in-vacuum leak detector. The second is a bilateral, force-reflecting pair of slave arms which utilize specially developed tools to perform several maintenance functions. All components except the slave arms are capable of operating in TFTR's vacuum environment and during 150°C bakeout of the torus.

Automatic control of gas pressure in a vacuum system: J Lucas et al, Vacuum, 32 (5), 1982, 2572̄263

TFTR plans to begin D—T experiments in mid 1990. The D—T experimental program will produce approximately one hundred shots, with a neutron generation rate of 1019 neutrons per shot. This will result in high levels of activation in TFTR, especially in the vacuum vessel. The primary purpose of the Maintenance Manipulator is to provide a means of remotely performing certain defined maintenance and inspection tasks inside the vacuum torus so as to minimize personnel exposure to radiation.The manipulator consists of a six-link folding boom connected to a fixed boom on a movable carriage. The entire manipulator is housed in a vacuum antechamber connected to the vacuum torus, through a port formerly used for a vacuum pumping duct. The configuration extends 180° in either direction to provide complete coverage of the torus. The four 3500 1/s turbopumps which were formerly used in the pumping duct will be mounted on the antechamber. The manipulator will utilize two end effectors. The first, called a General Inspection Arm (GIA) provides a moveable platform to an inspection camera and an in-vacuum leak detector. The second is a bilateral, force-reflecting pair of slave arms which utilize specially developed tools to perform several maintenance functions. All components except the slave arms are capable of operating in TFTR's vacuum environment and during 150°C bakeout of the torus.