New approaches are presented for calculating and designing radiation shielding on nuclear power systems used in space. A method for optimizing and profiling the radiation shielding is described. The method is based on using the input current and elements of optimal control theory. As an example, the heavy component of the radiation shielding for a conventional space craft with a nuclear power system on board is optimized and profiled. Two- and three-dimensional profiles of the shielding are presented. It is shown that the method makes it possible to eliminate somewhat more than 500 kg.