When a strong neutrino flux, emitted by a collapsing stellar core, interacts with the helium shell of a star, it can destroy some amount of 4 He to give rise to thermonuclear reactions of importance for the synthesis of light isotopes (e.g., 7 Li). It will also be responsible for production of free neutrons under favorable conditions to drive r-process. We have undertaken a series of calculations aimed at specifying the physical conditions (initial temperature and density of the shell, its distance from stellar center, initial admixture of Fe, 1 4 N and other metals ) favorable for a noticeable contribution of this process to cosmic abundances. Heating of the shell due to neutrino interaction with stellar matter was taken into account.