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

TLDR

WEST is a superconducting, actively cooled, full tungsten tokamak designed for long‑pulse operation up to 1000 s, aimed at qualifying high‑heat‑flux plasma‑facing components and demonstrating steady‑state confinement relevant to ITER divertor technology. This paper provides an overview of phase‑1 results and outlines prospects for phase‑2 operation with the full ITER‑grade actively cooled lower divertor. Phase‑1 operation involved integrating actively cooled ITER‑grade plasma‑facing unit prototypes into the inertially cooled tungsten‑coated startup lower divertor. Phase‑1 achieved up to 8.8 MW RF power and divertor heat fluxes of 6 MW m⁻², and demonstrated the first long‑pulse discharge of roughly one minute using the upper actively cooled divertor.

Abstract

Abstract 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.