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Atomic Icebreaker Characteristics
Nuclear Power Plant
Atomic lighter Sevmorput
Atomic Icebreakers Technical Data



State Atomic Energy Corporation Rosatom

Joint Stock Company Atomic Energy Power Corporation

Press center of nuclear energy and industry

Public Council of state corporation Rosatom

Nuclear power plant of an atomic vessel consists of one or two autonomous atomic steam-producing plants (ASPP), steam-turbine (ST) and electric propulsive plant (EPP), two marine power plants, auxiliary gear, service systems and marine equipment.

ASPP Types

Since 1959 5 types of ASPP have been used on atomic icebreakers: OK-150, OK-900, OK-900A, KLT-40 and KLT-40M.

ASPP types on atomic icebreakers

ASPP type,
vessel name

OK-150
Lenin
(till 1966.)

OK-900
Lenin

OK-900A
Arktika, Sibir, Rossiya ,Sov. Souz,
Yamal, 50 Let Pobedy

KLT-40
Sevmorput

KLT-40M
Taimyr Vaygach

Available reactor power , MW

390

2159

2171

1135

1171

Available steam capacity, t/h

3120

2220

2240

215

240

Propeller power, h/p

44 000

44 000

75 000

40 000

50 000

Design

All plants have block type arrangement. Each block includes water-cooled reactor (when water is both coolant and neutron moderator), four circulation pumps and four steam generators, volume compensators, ion exchange filter with freezer and other equipment. The reactor, pumps, and steam generators have separate cases and are interconnected with short nozzles of pine-in-pipe type. All equipment is vertically placed in caissons of iron-and-water protection tank and closed with small protection blocks thus granting easy access during repair works.

The Reactor

A nuclear reactor is a plant where controlled chain reaction is carried out when nuclear energy is released in the process of heavy elements nuclei fission. A reactor consists of a core and a reflector. A core holds nuclear fuel in protective cover (fuel elements) and moderator. Fuel elements that look like thin rods are fasciculated and put into cases. Such constructions are called fuel assemblies. Reactor core consists of 241 fuel assemblies.

Reactor vessel with elliptic bottom is made of low-alloyed hot-work steel with anti-corrosive welding on inner surface.

ASPP Principle of operation

ASPPA marine ASPP has 4 loops. The coolant (highly purified water) of the 1st loop is pumped through the core. The water is boiled up to 317 Centigrade but does not vaporize since it is under pressure. The coolant of the 1st loop is pumped from the reactor to a steam generator into the pipes where the 2nd loop water flows which turns into superheated steam. Then the 1st loop coolant is forced into the reactor by a circulating pump.

The overheated steam (2nd loop coolant) from a steam generator is sent to the main turbines. Steam characteristics before the turbine: 30 kg/cm2 (2,9 MPa), temperature + 300 . Then the steam is condensed, the water undergoes the procedure of ion exchange cleaning and is again pumped into a steam generator.

3rd loop is used to cool the ASPP equipment where highly purified water (distillate) is used as a coolant. The 3rd loop coolant has very low radioactivity.

4th loop is used to cool water in the 3rd loop; sea water is used as coolant. 4th loop is also used to cool steam of the 2nd loop during arrangement and shut-down cooling of the plant.

Safety

ASPP is designed and placed to shield the crew and population from irradiation and protect environment against contamination with radioactive wastes. The four protective barriers between nuclear fuel and environment are constructed for this purpose:

First core fuel elements casings;

Second sturdy walls of equipment and pipelines of the 1st loop;

Third protective casing of the reactor;

Fourth protective shielding with longitudinal and transversal walls, second bottom and deck plating in the area of reactor compartment.

ASPP safety is provided by equipment and systems for normal operations and safety systems for reliable reactor shutdown, heat extraction and minimizing the consequences of potential accidents.

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