Tungsten is proposed as a tokamak divertor armour due to its good erosion resistance. Combining tungsten coatings with copper as a base material can overcome problems with machinability, lower the weight and reduce the component cost. The erosion rate must be known to estimate the lifetime of plasma facing components.This work aims to compare selected tungsten coatings to check if the erosion rate remains as good. It also compares the experimental data to a developed code based on previous work that aims to be quick and simple while giving reasonable results. In this study a set of erosion experiments were undertaken to measure the sputter yield in different conditions at partner organisations; Helium ion beam erosion at Huddersfield University, Helium plasma erosion at the University of Liverpool, Argon plasma erosion at Plasma Quest Ltd and Xenon Focussed Ion Beam (FIB) erosion at University of Surrey This work compares sputter yields different tungsten samples: sheet material, Chemical Vapour Deposition tungsten coating, Additive Manufacture deposited tungsten and tungsten coatings laid down by Thermal Plasma Spray. These coatings are available commercially so are ready to deploy today. The experimental sputter yields were compared to theoretical predictions, based on previously published work. While the experimental results agreed well with the models in trend and angular dependence the quantitative agreement was only well predicted to within a factor of four.It was found that the coatings have similar, and sometimes slightly lower sputter yields, and therefore, on occasion, slightly better erosion performance than the stock tungsten sheet samples.

Modelling the structural effects of vertical displacement events (VDEs) on plasma facing components is critical for component integrity but can be time consuming. In early-stage design, a simple analysis method is useful to compare concepts. This paper describes methods that use the commercially available ANSYS software to obtain estimations of forces and torques on components arising from VDE induced currents and halo currents. The methods will be used to inform the design of in-vessel assemblies on Tokamak Energy Ltd's future machines.

Tokamak Energy's ST40 spherical tokamak, operating in a double null diverted configuration, has a design basis of toroidal field Bt = 3 T on-axis (R = 40 cm), and plasma current Ip = 2MA. The procurement and installation of the top and bottom divertors for installation into ST40 was anticipated to be completed on a quick timescale of approximately ten weeks. The difficulties inherent in a tight deadline were exacerbated by the necessary social distancing measures introduced to combat the global crisis of COVID-19. This paper describes the procurement and installation of the divertors, the design is described in the sister paper [1], authored by Daniel Iglesias.