[en] The problem was raised whether the change in certain measurable quantities of a reactor can lead to the change of total reactor performance which, in turn, can be utilized for obtaining information on parameters such as radiation shielding materials. The question can be answered by the sensitivity analysis for cross sections. The role of sensitivity analysis is presented for the determination of integral parameters and for the calculation of biological radiation protection data. The results for a sensitivity analysis case are presented in detail. (D.Gy.)