Operating a full tungsten actively cooled tokamak: overview of WEST first phase of operation

WEST is an MA class superconducting, actively cooled, full tungsten (W) tokamak, designed to operate in long pulses up to 1000 s. In support of ITER operation and DEMO conceptual activities, key missions of WEST are: (i) qualification of high heat flux plasma-facing components in integrating both technological and physics aspects in relevant heat and particle exhaust conditions, particularly for the tungsten monoblocks foreseen in ITER divertor; (ii) integrated steady-state operation at high confinement, with a focus on power exhaust issues. During the phase 1 of operation (2017–2020), a set of actively cooled ITER-grade plasma facing unit prototypes was integrated into the inertially cooled W coated startup lower divertor. Up to 8.8 MW of RF power has been coupled to the plasma and divertor heat flux of up to 6 MW m−2 were reached. Long pulse operation was started, using the upper actively cooled divertor, with a discharge of about 1 min achieved. This paper gives an overview of the results achieved in phase 1. Perspectives for phase 2, operating with the full capability of the device with the complete ITER-grade actively cooled lower divertor, are also described

Réglage automatique temps-réel de l'estimateur de dérapage d'un avion de transport

National audienc

Real-time Automatic Tuning of an Aircraft Sideslip Estimator

International audienc

Aircraft Airbrakes Compensation Design Using Iterative Inversion

International audienc

WEST regular in-vessel inspections with the Articulated Inspection Arm robot

International audienceCurrently on fusion devices, diagnostics are mainly aiming at plasma analysis and control. However, operational and programmatic needs have appeared for regular in-vessel components monitoring during plasma campaign. Light robotics systems could meet this requirement and may be a way as well to replace human interventions to fix damaged in vessel components. To minimize the impact on machine operation, the robotic system has to be mini-invasive and compatible with operating conditions (vacuum, temperature, radiation…). To fulfill this goal, CEA has developed a multipurpose carrier able to be operated inside WEST vessel between plasma pulses. A prototype of this robot, called Articulated Inspection Arm (AIA), was tested in 2008 in Tore Supra vacuum vessel. A major upgrade was performed in 2014-2015 with the aim of converting this prototype into a reliable tool in support to WEST operation. During the WEST components manufacturing and installation (2014-2016), the robot was integrated and tested in the EAST Tokamak. Since 2017, the AIA has been regularly used during the WEST plasma campaigns. Movies provided by the embedded camera allow to assess the evolution of Plasma Facing Components surface state and the effects of plasma loads, runaways and disruptions. The robot operation was also very helpful to assess the needs for maintenance, to assist mechanical assembly without man entry and to perform diagnostics calibration under relevant conditions. The paper will detail lessons learned from the robot integration and use on the WEST Tokamak. Future developments for innovative embedded diagnostics will also be presented

SELFIE: ITER superconducting joint test facility

In the frame of a contract with ITER Organization (IO) on magnets assembly support, CEA designed and built a superconducting joint test facility called SELFIE (ITER SELf-FIEld joint test facility). This facility is installed at CEA Cadarache and started to operate in 2022. This project was initiated by IO for quality control of critical assembly activities. Indeed, the magnet superconducting joints assembly is a special process, for which the performance cannot be verified until the full Tokamak is at cryogenic temperature and obviously repair cannot be envisaged once the machine is assembled. Therefore, the quality control of these joints assembly relies on procedures and qualification of the workers in charge of their implementation. As the joints assemblies will span over three years of the ITER construction, the qualified workers will have to assemble periodically some Production Proof Samples (PPS) joints to train and keep their certification valid. The purpose of SELFIE is to test these PPS in a timely manner. The tests scope is the measurement of the PPS resistance (few nOhms). For that purpose, PPS integrated in ITER conductors length (∼200 kg weight and 3600 mm length) are tested in a liquid helium bath (4.2 K), at nominal current (up to 70 kA), in self-field. The current is provided by a superconducting transformer integrated in the same cryostat as the sample. CEA finalized the preliminary design in 2019, complying with the requirement to achieve a full test sequence within one week (controlled cool down, test and warm-up), with an optimised operation cost. The detailed design phase was started in April 2020 followed by the manufacturing phase up to mid 2021. SELFIE integration and installation were achieved in December 2021 and the cold commissioning done in January 2022. This paper presents the SELFIE test facility and the first results