A new 3MW ECRH system at 105 GHz for WEST

The aim of the WEST experiments is to master long plasma pulses (1000s) and expose ITER-like tungsten wall to deposited heat fluxes up to 10 MW/m$^2$. To increase the margin to reach the H-Mode and to control W-impurities in the plasma, the installation of an upgraded ECRH heating system, with a gyrotron performance of 1MW/1000s per unit, is planned in 2023. With the modifications of Tore Supra to WEST, simulations at a magnetic field B$_0$∼3.7T and a central density n$_{e0}$∼6 × 10$^{19}$ m$^{−3}$ show that the optimal frequency for central absorption is 105 GHz. For this purpose, a 105 GHz/1MW gyrotron (TH1511) has been designed at KIT in 2021, based on the technological design of the 140 GHz/1.5 MW (TH1507U) gyrotron for W7-X. Currently, three units are under fabrication at THALES. In the first phase of the project, some of the previous Tore Supra Electron Cyclotron (EC) system components will be re-installed and re-used whenever possible. This paper describes the studies performed to adapt the new ECRH system to 105 GHz and the status of the modifications necessary to re-start the system with a challenging schedule

Backward Compatible Update of the Timing System of WEST

International audienceBetween 2013 and 2016, the tokamak Tore Supra in operation at Cadarache (CEA-France) since 1988 underwent a major upgrade following which it was renamed WEST (Tungsten [W] Environment in Steady state Tokamak). The synchronization system however was not upgraded since 1999*. At the time, a robust design was achieved based on AMD’s TAXI chip**: clock and events are distributed from a central emitter over a star shaped network of simplex optical links to electronic crates around the tokamak. Unfortunately, spare boards were not produced in sufficient quantities and the TAXI is obsolete. In fact, multigigabit serial communication standards question the future availability of any such low rate SerDeses. Designing replacement boards provides an opportunity for a new CDR solution and extended functionalities (loss-of-lock detection, latency monitoring). Backward compatibility is a major constraint given the lack of resources for a full upgrade. We will first describe the current state of the timing network of WEST, then the implementation of a custom CDR in full firmware, using the IOSerDeses of Xilinx FPGAs and will finally provide preliminary results on development boards

A Conclusive Concept for Three-Dimensional Imaging Based on Efficient Steering and Focusing of an Ultrasonic 2D-Array

Abstract. A 16-by-16 element array is operated at a center frequency of 2.25 MHz using a 256-channel transmitter system. Reception is performed with a subset of elements of the array or with a separate single element probe. The beam fields generated in water have been simulated and compared to experiments with excellent agreement. 3D imaging of defects inside components has been addressed only by electronic steering and focusing to various depths of the inspected component. Work has also been done using an 8-by-8 element array

WEST operation with real time feed back control based on wall component temperature toward machine protection in a steady state tungsten environment

International audienceA real time Wall Monitoring System (WMS) is used on the WEST tokamak during the C4 experimental campaign. The WMS uses the wall surface temperatures from 6 fields of view of the Infrared viewing system. It extracts the raw digital data from selected areas, converts it to temperatures using the calibration and write it on the shared memory network being used by the Plasma Control System (PCS). The PCS feeds back to actuators, namely the injected power from 5 antennae's of the lower hybrid and ion cyclotron resonance radiofrequency (RF) heating systems. WMS activates feed back control 63 times during C4, which is 14% of the plasma discharges. It activates mainly as the result of a direct RF loss to the upper divertor pipes. The feedback control maintains the wall temperature within the operation envelope during 97% of the occurrences, while enabling plasma discharge continuation. The false positive rate establishes at 0.2%. WMS significantly facilitated the operation path to high power operation during C4, by managing the technical risks to critical wall components

Preliminary Study of Electronics Reliability in ITER Neutron Environment

International audienceWe validated a method for predicting the Soft Error Rate (SER) in the WEST tokamak operated with deuterium plasmas, and we applied it to predict the SER in the ITER tokamak operated with deuterium-tritium plasmas

Preliminary Study of Electronics Reliability in ITER Neutron Environment

International audienceWe validated a method for predicting the Soft Error Rate (SER) in the WEST tokamak operated with deuterium plasmas, and we applied it to predict the SER in the ITER tokamak operated with deuterium-tritium plasmas

Fusion Neutron-Induced Soft Errors During Long Pulse D-D Plasma Discharges in the WEST Tokamak

International audienceWe conducted real-time SER measurements on bulk 65 nm SRAMs in the WEST tokamak during long pulse deuterium-deuterium plasma discharges (~60 s), evidencing bursts of SEUs during the most efficient shots and 12% of MCU events

Preliminary Study of Electronics Reliability in ITER Neutron Environment

International audienceWe validated a method for predicting the Soft Error Rate (SER) in the WEST tokamak operated with deuterium plasmas, and we applied it to predict the SER in the ITER tokamak operated with deuterium-tritium plasmas

Fusion Neutron-Induced Soft Errors During Long Pulse D-D Plasma Discharges in the WEST Tokamak

International audienceWe have performed real-time soft error rate (RT-SER) measurements on bulk 65-nm static random access memories (SRAMs) during deuterium–deuterium (D-D) plasma operation at W–tungsten–Environment in Steady-state Tokamak (WEST). The present measurement campaign was characterized by the production of several tens of long pulse discharges (∼60 s) and by a total neutron fluence (at the level of the circuits under test) up to ∼10 9 n·cm−2, improving the error statistics by a factor of more than 6 with respect to the first measurements obtained in 2020. The experimental results demonstrate the occurrence of bursts of single-event upsets (SEUs) during the most efficient shots and 12% of multiple cell upset (MCU) events. Time-resolved data also show that MCUs are preferentially detected in the last part of these long pulses, providing further evidence that higher energy neutrons, initiated by deuterium–tritium (D-T) reactions due to triton burn-up in the D-D plasma, may play a role in the production of MCUs that cannot be attributed in such large proportions to “low-energy” neutrons produced in D-D reactions

Fusion Neutron-Induced Soft Errors During Long Pulse D-D Plasma Discharges in the WEST Tokamak

International audienceWe conducted real-time SER measurements on bulk 65 nm SRAMs in the WEST tokamak during long pulse deuterium-deuterium plasma discharges (~60 s), evidencing bursts of SEUs during the most efficient shots and 12% of MCU events