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The SOLPS‐ITER3.0.8 code with new Grad‐Zhdanov module was applied for predictive modeling of tritium plasma and deuterium‐tritium mixture in tokamak JET. The moderate power scenario of shot JPN #85278 modeled earlier for deuterium plasma was taken as a starting point. Effect of puffing increase, which was applied in experiment, on divertor conditions and inter‐ELM tungsten sputtering for both working gases and on isotope separation in their mixture is analyzed. Both for attached and for semi‐detached outer targets, the tritium plasma shows moderate increase in SOL width compared to deuterium one. The tungsten sputtering at the outer target in the inter‐ELM period for tritium is an order of magnitude bigger than that for deuterium. The D–T separation in the D–T mixture is moderate. [ABSTRACT FROM AUTHOR]

Numerical scan at constant β shows that core and scrape‐off layer (SOL) radiations do not depend on the plasma current (Ip). Whereas the SOL radiation increases with seeding, the core radiation, however, does not continue to increase with seeding but rolls over at higher seeding rates in the simulations. The core plasma contamination by W ions is low, cW ≪ 10−4. When the seeding starts, an increase in radiation power leading to a reduction in Ploss = (Paux − Prad) is observed, influencing the plasma confinement. The power scan at constant Ip indicates that the core radiation, Pplate, PSOL (and even SOL radiation), saturates with seeding. In addition, strong dilution with increasing seeding (Zeff ≫ 3) and large W concentrations with increasing power are found. Comparing neon with nitrogen seeding, it is seen that neon leads to slightly larger total radiation than nitrogen. However, that is achieved with much higher plasma contamination (Zeff ∼ 4–5) and dilution in the case of Ne, and simultaneously the power crossing the separatrix is lower for Ne than for N, indicating better H‐mode performance in N2‐seeded discharges. [ABSTRACT FROM AUTHOR]