Materials have been presented as to experience in creating and operating Russian and partially foreign research and industrial test benches and reactor plants using heavy liquid-metal coolants (HLMC), i.e. lead-bismuth and lead coolants. Main performance data of reactor circuits, major equipment and their design solutions have been described. There has been provided information on specific features of operating conditions, including operating basis accidents of power circuits cooled with lead and lead-bismuth coolants. This book may be recommended as a teaching aid for students, masters and graduate students learning with specializations related to the nuclear power industry and principally to innovative fast neutron reactors cooled with HLMC. It may be of some interest for researchers, scientific workers and engineers engaged in creating and operating such installations.