Project 705 and 705K submarines had record high underwater speed (more than 40 knots) and maneuverability, they successfully completed several long autonomous trips. It took them about 1 minute to accelerate to full speed, and it took 42 seconds to circulate with a 180° turn. For speed, the submarine of project 705 was even listed in the Guinness Book of Records.

At the same time, even with good PPU, the operation of the boats of projects 705 and 705K with LMT had certain difficulties, such as the difficulty of eliminating malfunctions due to the tightness of the reactor compartment, the need for an external energy source when being at the base with the reactor shut off, the need for regular regeneration of the coolant ... for these problems in the early 90s, when the submarine fleet began to decline, they began to be decommissioned. The K-705 submarines were decommissioned in 1990, and the 705K submarines in 1996.

The commanders and officers of submarines with reactor facilities developed at the IPPE gave a very high rating to the submarine itself and its nuclear power plant, calling it a “miracle boat” that was far ahead of its time.

Today it can be considered universally recognized that in the IPPE under the direction of A.I. Leypunsky laid the foundations for a new direction in nuclear energy, and a unique reactor technology was demonstrated on an industrial scale. This made it possible to ensure the compactness of the reactor installation, which is important when creating submarines of limited displacement, to ensure high maneuverability, and to increase the reliability and safety of the reactor installation.

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With the withdrawal of the last submarine from the Navy from the Navy, a certain stage in the development of ship nuclear energy was completed. The use of liquid metal coolant reactors in nuclear submarines has two opposing views. Some, and most of them, considered this a mistake due to the accident rate and low reliability of the equipment. Others pointed to the high combat qualities of the nuclear submarines: project 705 and 705K boats could successfully evade enemy torpedoes precisely at the expense of speed and maneuverability, short time to bring the reactor out of a subcritical state into energy mode, and ease of control.

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In April 1982, during a cruise of the K-123 nuclear submarine, a PPU accident occurred - due to improper crew actions, the alloy was thrown into the compartment through the impulse pipe of the gas system. PPU had to be taken out of action and “frozen”. The subsequent revision of the PUF also revealed irreparable great corrosion damage to the steam generator pipe systems from the side of the secondary circuit, which required a complete replacement of the PPU compartment (there was a replacement BM-40A installation kit).