Impurity modeling of Infinity Two Fusion Power Plant Design

“Infinity Two” is Type One Energy’s proposed design for a fusion power plant (FPP) with a robust baseline physics solution and a conservative design margin [1]. To mitigate the high heat loads to the divertor, the reactor will be operated in detached conditions using impurity seeding to radiate away most of the power entering the scrape-off layer [2]. Infinity Two is being designed to have tungsten walls along with impurity seeding to maintain stable detachment conditions. Recent results have shown that the W7-X stellarator is able to sustain a stable detachment scenario with island divertors at high radiation fraction above 90% [3]. To leverage this, the present work is aimed at modelling of the radiation zone location and the radiative profiles for low Z impurity seeding. The modelling was done using the impurity module of EMC3-EIRENE code [4]. Simulation of impurities is also essential to estimate the erosion of plasma facing components and the migration of impurities to the plasma core. This will determine the lifetime of the wall and divertor components and the fuel dilution of the plasma. This modeling is done using a dedicated impurity transport code like ERO2.0 [4]. Further, a 0D model erosion model is used to estimate the lifetime for both the first wall and divertor.

[1] C. C. Hegna et al., J. Plasma Phys. 2025

[2] A. Bader et al., J. Plasma Phys. 2025

[3] V.R. Winters et al Nucl. Fusion 2024

[4] Feng Y. et al Contrib. Plasma Phys 2014

[5] Romazanov J. et al Nucl. Mater. Energy 2019