The aim of this paper is to present a new way to produce a high flow of hydrogen radical, at low temperatures. Thirst, an atmospheric pressure plasma of an argon-hydrogen mixture generates a high flow of hydrogen radical at temperatures up to 5000 K. The applications of these radicals, in such conditions, are limited by thermal aspects which are obviously different from classical reactions of hydropyrolysis or other treatment processings of organic molecules. Our approach is to quench the plasma by a fluidized bed reactor which transport properties are compatible with plasma phase ((1)). From this point of view, the plasma/fluidized bed system is qualified in terms of its thermodynamic and hydrodynamical properties and its quenching velocity. The atomic hydrogen flow generated within such conditions is calculated and then experimentally measured.