Wall heat flux from radiative heat sources distributed in a toroidal space

A calculation method of wall heat flux from radiative heat sources distributed in a toroidal space is presented. The first walls are modeled by a continuous surface with uniformity in the toroidal direction. It is assumed that radiative heat sources are distributed within the poloidal cross section, while have an uniform distribution in the toroidal direction. The model wall surface and radiative area have symmetry with respect to the horizontal mid-plane of the torus. It is also assumed that radiation is emitted isotropically and transferred without absorption in the space, and then absorbed on the first walls without reflection. Based on these assumptions, the general description for the radiative heat flux is derived. For the numerical calculation, an idea of ''light path cross section'' is introduced to deal with the torus having a complicated poloidal cross section such as JT-60. Finally, results of the computation are demonstrated for the JT-60 ''high compression case'' where a strong radiative remote cooling occurs in the magnetic limiter chamber. (author)