Abstract: The invention relates to nuclear physics and can be used for neutralizing long-lived radioactive isotopes contained, for example, in radioactive waste (RW) of the nuclear engineering. A radioactive isotope undergoes exposure to electromagnetic radiation and a deep ionization of the isotope atoms is performed. Deep ionization of the atoms results in an energy-permitted expedient B-decay thereof prohibited in a neutral state. Measures are taken in order to prevent ionized atoms from recombination with short-lived nucleus. The retention time must be long enough to transmit at least a part of the parent nucleus into the short-lived and stable daughter nucleus. For ensuring a factor k of an operating time of said daughter nucleus, the retention is performed at least during a time Ki, i is a life time of the parent nucleus at the expedient B-decay. A charge-particle beam (electrons, protons or ions) is used for electromagnetic irradiation.