ITER Remote Maintenance System (IRMS) lifecycle management

Concept of operation of the Agile Robot Transporter for ITER in-vessel maintenance

Remote handling (RH) system is necessary for the maintenance and repair of in-vessel components of JT-60SA. Design study of RH system, focusing on the deployment of the toroidal rail and replacement of the lower divertor cassettes, is described in this paper. The space for RH system is very limited inside the vacuum vessel and horizontal port. The RH rail is installed before transporting divertor cassettes. The RH rail, which is coupled with six pieces and three-point mounting, can cover 180 degrees in toroidal direction. A divertor cassette can be replaced by vehicle manipulator that consists of an end effector, a telescopic arm and a vehicle. The vehicle manipulator brings the divertor cassette to the front of another horizontal port, which is used for supporting the rail and/or carrying in and out equipments. Then another RH device, which is installed from outside the vacuum vessel, receives and brings out the divertor cassette. The basic designs of RH system for deployment of the RH rail and replacing lower divertor cassettes are established.

Specialized Remote Handling (RH) equipment are required which are controllable with high precision and accuracy for the efficient remote maintenance of tokamaks. These RH systems are not fully autonomous and most of the tasks are carried out by the trained RH operators. As these RH operations may directly impact the availability of the machine for the plasma experiments, huge efforts are being made to equip the RH operators with the advanced technologies that provide the real knowledge and interactions with the operating environment without being physically present. It can be very beneficial for the offline training and also during the RH operations. In this paper, a control mechanism is presented for the Virtual Reality (VR) based monitoring and controlling of the articulated in-vessel inspection arm. This arm is a six axis RH equipment capable of visual inspection inside the torus. The presented work addresses the challenges of achieving accurate mapping of the joints with the VR model. The kinematics based on the D-H parameters has been used. A control application is executed to communicate the joint pose and orientation along with the velocities from the VR simulations to the servo control system of the RH equipment. For the continuous tracking of the arm, the VR model is periodically updated with the values read from the encoders mounted in the articulated arm. In the event of the failure of equipment controller drives, it is important to recover the joint positions. The rescue of the arm can be planned using the VR platform. The initial performance tests show a low latency with precise and accurate control over the RH equipment. The system can also be used as a training platform for the RH operators.

ERGONOMIC ANALYSIS OF A TELEMANIPULATION TECHNIQUE FOR A PYROPROCESS DEMONSTRATION FACILITY

The JT-60SA aims to contribute and supplement ITER toward DEMO reactor based on tokamak concept. One of the features of JT-60SA is its high power long pulse heating, causing the large annual neutron fluence. Because the expected dose rate at the vacuum vessel (VV) may exceed 1 mSv/hr after 10 years operation and three month cooling, the human access inside the VV is prohibited. Therefore a remote handling (RH) system is necessary for the maintenance and repair of in-vessel components. This paper described the RH system of JT-60SA, especially the expansion of the RH rail and exchange of the divertor modules. The RH rail is divided into nine and three-point mounting. The nine sections can cover 225 degrees in toroidal direction. A divertor module, which is 10 degrees wide in toroidal direction and weighs 500kg itself due to the limitations of port width and handling weight, can be exchanged by heavy weight manipulator (HWM). The HWM brings the divertor module to the front of the other RH port, which is used for supporting the rail and/or carrying in and out equipments. Then another RH device receives and brings out the module by a pallet installed from outside the VV.

In 1997 a series of experiments were performed in the JET machine using deuterium-tritium (D-T) mixtures and resulting in discharges with record breaking fusion power and fusion energy. The experiments demonstrated a key technology required for fusion, namely the on-line operation of a tritium fuel re-processing plant.These experiments left the inside of the JET vessel inaccessible to manned access for approximately one year. During this time, the complete Mark IIA divertor, a major system within the torus, was successfully removed and replaced with a new divertor design, the Mark II Gas Box divertor, using only remote handling techniques. This was the first application of the JET remote handling system and a demonstration of a further key ITER technology.The paper explains the methodology and operational approach taken to achieve the results using the remote handling system developed at JET. It describes the remote handling equipment including the force-reflecting servomanipulator, the specialised tools designed, the facilities needed, and the trials, planning and training carried out to ensure the safe, reliable and rapid completion of the remote handling tasks. The planned tasks are outlined including the execution of the novel procedure for a remote, sub-millimetre precision, dimensional survey of the divertor support structure using digital photogrammetry. Furthermore the paper shows how the adaptability of the system was used to successfully undertake a large number of unplanned tasks including the removal of damaged tiles, a damaged diagnostic system and the vacuum cleaning of diagnostic windows.

The ITER EC H&CD Upper Launcher: Analysis of vertical Remote Handling applied to the BSM maintenance

CODAC systems arrangement and connectivity

Laser-induced breakdown spectroscopy (LIBS) is one of the most promising methods for quantitative in-situ determination of fuel retention in plasma-facing components (PFCs) of magnetically confined fusion devices like ITER and JET. In this article, the current state of understanding in LIBS development for fusion applications will be presented, based on a complete review of existing results and complemented with newly obtained data. The work has been performed as part of a research programme, set up in the EUROfusion Consortium, to address the main requirements for ITER: (a) quantification of fuel from relevant surfaces with high sensitivity, (b) the technical demonstration to perform LIBS with a remote handling system and (c) accurate detection of fuel at ambient pressures relevant for ITER. For the first goal, the elemental composition of ITER-like deposits and proxies to them, including deuterium (D) or helium (He) containing W–Be, W, W–Al and Be–O–C coatings, was successfully determined with a typical depth resolution ranging from 50 up to 250 nm per laser pulse. Deuterium was used as a substitute for tritium (T) and in the LIBS experiments deuterium surface densities below 1016 D/cm2 could be measured with an accuracy of ∼30%, confirming the required high sensitivity for fuel-retention investigations. The performance of different LIBS configurations was explored, comprising LIBS systems based on single pulse (pulse durations: ps–ns) and double pulse lasers with different pulse durations. For the second goal, a remote handling application was demonstrated inside the Frascati-Tokamak-Upgrade (FTU), where a compact, remotely controlled LIBS system was mounted on a multipurpose deployer providing an in-vessel retention monitor system. During a shutdown phase, LIBS was performed at atmospheric pressure, for measuring the composition and fuel content of different area of the stainless-steel FTU first wall, and the titanium zirconium molybdenum alloy tiles of the toroidal limiter. These achievements underline the capability of a LIBS-based retention monitor, which complies with the requirements for JET and ITER operating in DT with a beryllium wall and a tungsten divertor. Concerning the capabilities of LIBS at pressure conditions relevant for ITER, quantitative determination of the composition of PFC materials at ambient pressures up to 100 mbar of N2, the D content could be determined with an accuracy of 25%, while for atmospheric pressure conditions, an accuracy of about 50% was found when using single-pulse lasers. To improve the LIBS performance in atmospheric pressure conditions, a novel approach is proposed for quantitative determination of the retained T and the D/T ratio. This scenario is based on measuring the LIBS plume emission at two different time delays after each laser pulse. On virtue of application of a double pulse LIBS system, for LIBS application at N2 atmospheric pressure the distinguishability of the spectra from H isotopes could be significantly improved, but further systematic research is required.

Radiation enhanced degradation of aluminium mirrors for remote handling and diagnostics applications: Effect of humidity

The SPES (Selective Production of Exotic Species) facility, currently under development at Legnaro National Laboratories of INFN, aims at the production of intense RIB (Radioactive Ion Beams) employing the Isotope Separation On-Line (ISOL) technique for interdisciplinary research. The radioactive isotopes of interest are produced by the interaction of a multi-foil uranium carbide target with a 40 MeV 200 μA proton beam generated by a cyclotron proton driver. The Target Ion Source (TIS) is the core of the SPES project, here the radioactive nuclei, mainly neutron-rich isotopes, are stopped, extracted, ionized, separated, accelerated and delivered to specific experimental areas. Due to efficiency reasons, the TIS unit needs to be replaced periodically during operation. In this highly radioactive environment, the employment of autonomous systems allows the manipulation, transport, and storage of the TIS unit without the need for human intervention. A dedicated remote handling infrastructure is therefore under development to fulfill the functional and safety requirement of the project. This contribution describes the layout of the SPES target area, where all the remote handling systems operate to grant the smooth operation of the facility avoiding personnel exposure to a high dose rate or contamination issues.

Remote handling tools for hydraulic connections of divertor cassettes in JT-60SA

Preliminary concept design of the divertor remote handling system for DEMO power plant

Development of remote pipe welding tool for divertor cassettes in JT-60SA

The International Thermonuclear Experimental Reactor (ITER) project is a worldwide research experiment that aims to explore nuclear fusion as a viable source of energy for the coming years. Mobile robotics plays an important role in the remote handling systems that perform the maintenance operations in ITER. The Cask and Plug Remote Handling System (CPRHS) is one of the remote handling systems that transports heavy and highly activated in-vessel components between the Tokamak Building and the Hot Cell Building, the two main buildings of the ITER facility. The CPRHS has dimensions similar to an autobus, maximum weight of 100 tons, kinematics of a rhombic like vehicle (two drivable and steerable wheels) and has to move in cluttered environments. The main challenges described in this chapter are the definition of motion planning strategies that cope with the building maps and the cluttered environments. The algorithms were developed and implemented in a standalone application that receives CAD models of the buildings and returns the best trajectories, including reports of the most risky points of collision, and the swept volume of the vehicle along the missions. More than 700 trajectories were computed for different CPRHS types applied in the models of the real scenarios, crucial to proceed with the construction of the Tokamak Building.KeywordsLine guidanceFree roamingRemote handlingITER and Nuclear fusion facilities