  Radiation technologies have found wide application in power engineering,
medicine, biology and other areas of human activities. However, theoretical
calculations of nuclear reactions and, correspondingly, the interpretation of
experimental results appear model-dependent. The model-independent calculation
of the nuclear reaction must take into account the structure of the nuclear
ground state, the final-state nucleon interaction and the contribution of meson
exchange currents. These calculations can be carried out only with due regard
for realistic NN and 3N forces between nucleons and also, with the use of exact
methods of solving the many-body problem. In this technique it is expedient to
conduct investigations of nuclear reactions as from few-nucleon systems in the
energy area of the particles below the meson-producing threshold. The tensor
part of NN interaction and 3NF,s generate the lightest nuclei states with
nonzero orbital momenta of nucleons. These states in the lightest nuclei is
conditioned the properties of inter-nucleonic forces, and therefore, similar
effects should be observed unexceptionally in all nuclei. The review papers are
generally devoted to three-nucleon systems. In this paper primary attention is
given to the investigation of the $^4$He nucleus.
