A rotary device for a nuclear power facility, the rotary device being placed in a circuit for coolant containing radioactive nuclides in the nuclear power facility. The rotary device includes: a casing; and a rotary mechanism provided with, in the casing, a rotor and a rotor shaft that come into contact with the coolant containing the radioactive nuclides passing through the casing. Regarding the casing and the rotary mechanism, at least the rotor and the rotor shaft of the rotary mechanism comprise a low-effective diffusion coefficient alloy having a lower effective diffusion coefficient than a polycrystalline alloy.

A rotary device for a nuclear power facility, the rotary device being placed in a circuit for coolant containing radioactive nuclides in the nuclear power facility. The rotary device includes: a casing; and a rotary mechanism provided with, in the casing, a rotor and a rotor shaft that come into contact with the coolant containing the radioactive nuclides passing through the casing. Regarding the casing and the rotary mechanism, at least the rotor and the rotor shaft of the rotary mechanism comprise a low-effective diffusion coefficient alloy having a lower effective diffusion coefficient than a polycrystalline alloy.

The invention relates to the field of nuclear engineering and can be used to organize the natural circulation of liquid metal coolant in the heat sink of a fast neutron nuclear reactor.

In order to create a driving pressure of circulation without using pumping equipment and to provide the required direction of natural circulation of the liquid metal coolant in the heat sink circuit of the fast neutron nuclear reactor in the absence of heat transfer from the reactor before filling the pipelines and equipment of the lifting and downing sections of the circuit, they are pre-heated by electric heating to temperatures T.sub.1 and T.sub.2, respectively, which are selected from the condition of inequality: .sub.1(T.sub.1).Math.g.Math.H.sub.1>.sub.2(T.sub.2).Math.g.Math.H.sub.2+P, where: .sub.1(T.sub.1) is the density of the liquid metal coolant at temperature Ti of pipelines and equipment in the lifting section;

.sub.2(T.sub.2) is the density of the liquid metal coolant at temperature T.sub.2 of pipelines and equipment at the downing section;
H.sub.1 is the height difference between the inlet and outlet of the lifting section;
H.sub.2 is the height difference between the inlet and outlet of the downing section;
.sub.P is the hydraulic resistance of the circuit; g is the acceleration of gravity. The circulation of the coolant in the circuit and the transition to natural circulation mode are carried out simultaneously until the nuclear reactor reaches its rated operating parameters by creating a moving pressure of the circulation due to the difference in densities .sub.1(T.sub.1) and .sub.2(T.sub.2) of the liquid metal coolant on the lifting and downing sections of the circuit, respectively.

In one implementation, a passive core decay heat transport system comprising of a device in the reactor core and an assembly of heat dissipating fins is disclosed. The device comprises at least one coolant channel 2 containing the fuel assembly 3; at least one collect joint 4 connecting the fuel in the assembly to shield plug 6; at least one liquid metal thermo-siphon 5 for transporting of decay heat from fuel; at least one other liquid metal thermo-siphon 7 for transport of heat from thermo-siphon 5; and at least an assembly of heat dissipating fins 10 for transport of heat from thermo-siphon 7 to ultimate sink. The thermal expansion of the liquid metal by melting establishes the conductive and convective heat transfer paths and transfers the heat from the fuel assembly 3 to the thermo-siphon 5, which transports the heat to other thermo-siphon 7 and then to the assembly of fin 10, which dissipates the heat by natural circulation of air to atmospheric air.

Molten metal transfer pump, in which a shaft (4) with the impeller (5) mounted on the shaft (4) is installed on the upper bearing (2) and the lower journal plain bearing (3). The lower journal plain bearing (3) has rotor (15) and stator (16) parts. The rotor part (15) is made in the form of two split bushings (17) mounted on the shaft (4), and the stator part (16) is made in the form of two split bushings (18) fixed in the cage (19) in axial alignment with the shaft (4). Bushings (17) (18) are fixed correspondingly with flat rings (24) (33) and composed of cylinder segments (20), (28) equidistantly placed in a circumferential direction, located correspondingly in the cylindrical groove (21) on the shaft and cylindrical groove (29) of the cage (19) and fixed with cone hold-down rings (22), (30) radially, and with spring rings (23), (31) axially.

Passive safety systems cool reactors using surrounding ground as a heat sink. A coolant flow channel may loop around the reactor and then pass outside, potentially through a containment building, into surrounding ground. No active components need be used in example embodiment safety systems, which may be driven entirely by gravity-based natural circulation. The coolant loop may be air-tight and seismically-hardened and filled with any coolant such as water, air, nitrogen, a noble gas, a refrigerant, etc. The ground may include a soil of grey limestone, soft grey fine sandy clay, grey slightly silty sandy gravel, etc. or any other fill with desired heat-transfer characteristics. Coolant fins and/or jackets with secondary coolants may be used on the coolant loop. The coolant loop may be buried at any constant or variable depth, and the reactor and containment may also be buried in the ground.

Passive safety systems cool reactors using surrounding ground as a heat sink. A coolant flow channel may loop around the reactor and then pass outside, potentially through a containment building, into surrounding ground. No active components need be used in example embodiment safety systems, which may be driven entirely by gravity-based natural circulation. The coolant loop may be air-tight and seismically-hardened and filled with any coolant such as water, air, nitrogen, a noble gas, a refrigerant, etc. The ground may include a soil of grey limestone, soft grey fine sandy clay, grey slightly silty sandy gravel, etc. or any other fill with desired heat-transfer characteristics. Coolant fins and/or jackets with secondary coolants may be used on the coolant loop. The coolant loop may be buried at any constant or variable depth, and the reactor and containment may also be buried in the ground.

An electromagnetic pump (EMP) for a liquid metal-cooled nuclear reactor includes a pump casing, concentric inner and outer flow ducts collectively defining a flow annulus extending coaxially with a longitudinal axis of the EMP, and induction coils configured to control the flow of liquid metal coolant through the flow annulus based on electrical power received from the power supply. At least one of the inner flow duct or the outer flow duct includes a gamma shielding material configured to block gamma rays from entering an interior of the EMP from the flow annulus. The pump casing may include a neutron absorber material configured to absorb neutrons entering the pump casing from an exterior of the EMP. The EMP may include a neutron moderator material on an outer surface of the pump casing and configured to moderate neutrons entering the pump casing to be absorbed by the neutron absorber material.

An electromagnetic pump (EMP) for a liquid metal-cooled nuclear reactor includes a pump casing, concentric inner and outer flow ducts collectively defining a flow annulus extending coaxially with a longitudinal axis of the EMP, and induction coils configured to control the flow of liquid metal coolant through the flow annulus based on electrical power received from the power supply. At least one of the inner flow duct or the outer flow duct includes a gamma shielding material configured to block gamma rays from entering an interior of the EMP from the flow annulus. The pump casing may include a neutron absorber material configured to absorb neutrons entering the pump casing from an exterior of the EMP. The EMP may include a neutron moderator material on an outer surface of the pump casing and configured to moderate neutrons entering the pump casing to be absorbed by the neutron absorber material.

A nuclear reactor is designed to couple the load path of control elements with the reactor core, thus reducing opportunity for differential movement between the control elements and the reactor core. A core barrel can be fabricated in a manufacturing facility to include the reactor core, control element supports, and control element drive system. The core barrel can be mounted to a reactor vessel head. Movement, such as through seismic forces, transmits an equal direction and magnitude to the control elements and the reactor core, thus inhibiting the opportunity for differential movement.