[en] Accelerator driven spallation sources are nowadays designed and built as high flux and high energy neutrons sources for different purposes. The aim of this study is to investigate the applicability of such a realistic spallation source for the direct transmutation of minor actinides (MAs). A deeply subcritical and relatively low power blanket containing MAs, which is easier to build and operate, is designed around the target. The fuel assembly of the gas cooled nuclear reactor concept has been used for the structure and material composition of the blanket. The code MCNPX has been used for the transport calculations and the determination of the reaction rates. The code had to be modified in order to estimate the isotope transformation rates in the energy range of the physical models. A special code has been developed to follow the burn-up in the blanket with the matrix exponential method. The MA consumption has been investigated with different initial MA concentration. The results show that in the spectrum of the spallation neutrons the MAs can be transmuted more efficiently; however the flux of the fission neutrons can be higher in such extent which results in higher MA consumption. (authors)