[en] Various and generally very severe operating conditions characterize the possible applications of magnetic and electromagnetic filters in electronuclear industry. A modular type assembly of permanent magnets has been tested and optimization studies on the electromagnetic ball matrix filter were carried out in order to define the best working limits and efficiencies. In the particular case of the electromagnetic filter, a semi-empirical operating equation has been developed, which is a main issue of critical velocity measurements with a representative matrix. Fundamentally different items in plant operation are discussed. The possible use of a ferromagnetic scavenger in applications where non-ferromagnetic particles or colloids have to be filtered is related