The KLT-40 family are nuclear fission reactors originating from OK-150 and OK-900 ship reactors. KLT-40 were developed to power the Taymyr-class icebreakers and the LASH carrier Sevmorput. They are pressurized water reactors (PWR) fueled by either 30–40% or 90% enriched uranium-235 fuel to produce 135 to 171 MW of thermal power.