Session 3R - ITER.
POSTER session, Tuesday morning, November 12
Exhibit Hall - Concourse Level, Adam's Mark
Achieving simultaneous control of the divertor and bulk plasma parameters is an important problem facing the operation of fusion reactors. Indeed, the means to reduce the power reaching the divertor target plates - such as impurity seeding - impact strongly on the main plasma parameters and therefore on the produced fusion power. ITER will be the first experiment confronted to such a challenge, it is therefore important to study the feasibility of such a simultaneous control and the possible requirements made on the design of this device. To this effect, a set of reduced 1D equations have been developed to model the ITER divertor plasma parameters (temperature, density, neutral density) in detached and attached regimes as a function of upstream conditions: density, particle and heat flux and impurity level. These equations have been implemented as boundary conditions for a 1-1/2 D transport code (PRETOR) to model the core plasma transport and time dependent evolution. These tools are then used to study the impact of injection of high Z impurities - to maintain the power to the target plate below a maximum level - and varying helium removal rate on main plasma parameters and fusion power. Preliminary findings are that the predicted Argon and helium level in the main plasma are consistent with the ITER performances previously projected (i.e. similar ignition margin) and simultaneous control of the power to the target plates and the fusion power appears feasible.