The various types of the VM reactor series are nuclear pressurized water reactors (PWR). They are used singly or in pairs to power the Soviet Navy's submarines.
It was developed by NIKIET.
- The VM-A reactor was the nuclear fission reactor used in pairs to power the Soviet Navy's Project 658 and 701 (Hotel), Project 659 and 675 (Echo), and Project 627 Кит (November) first-generation submarines. It was a pressurized water reactor (PWR), using 20% enriched uranium-235 fuel to produce 70 MW of power. This is the reactor that powered the K-19.
- The VM-4 reactor is a nuclear fission reactor using 20% enriched uranium-235 fuel to produce 70-90 MW of power. It is used:
- singly to power the Project 670 Скат and Чайка-Б (Charlie) submarines
- in pairs to power the Project 671 Ёрш and Щука (Victor), Project 667 Мурена, Кальмар, and Дельфин (Delta), and Project 667 Навага, Налим, Груша, and Андромеда (Yankee) second-generation submarines.
- The VM-5 reactor was the nuclear fission reactor used in a pair to power the Soviet Navy's Project 661 Анчар (Papa) second-generation submarine. It was a pressurized water reactor (PWR) using enriched uranium-235 fuel to produce 177 MW of power.