Steam generators in power plants exchange energy from a primary medium to a secondary medium for energy extraction. Steam generators includes one or more primary conduits and one or more secondary conduits. The conduits do not intermix the mediums and may thus discriminate among different fluid sources and destinations. One conduit may boil feedwater while another reheats steam for use in lower and higher-pressure turbines, respectively. Valves and other selectors divert steam and/or water into the steam generator or to other turbines or the environment for load balancing and other operational characteristics. Conduits circulate around an interior perimeter of the steam generator immersed in the primary medium and may have different cross-sections, radii, and internal structures depending on contained. A water conduit may have less flow area and a tighter coil radius. A steam conduit may include a swirler and rivulet stopper to intermix water in any steam flow.

A nuclear power plant, having a reactor pressure vessel; a steam generator arranged to generate steam utilising thermal energy generated within the reactor pressure vessel; and a fluid circuit for transferring thermal energy from the reactor pressure vessel to the steam generator. The plant also has a coolant reservoir for storing coolant for supply to the steam generator under gravity in emergency conditions. The steam generator has a steam drying zone comprising one or more steam separators configured to dry steam; and the steam generator and coolant reservoir are configured such that when coolant is supplied from the coolant reservoir to the steam generator in emergency conditions the coolant stays below a threshold level defined by the steam drying zone.

A thermal control system for a reactor pressure vessel comprises a plate having a substantially circular shape that is attached to a wall of the reactor pressure vessel. The plate divides the reactor pressure vessel into an upper reactor pressure vessel region and a lower reactor pressure vessel region. Additionally, the plate is configured to provide a thermal barrier between a pressurized volume located within the upper reactor pressure vessel region and primary coolant located within the lower reactor pressure vessel region. One or more plenums provide a passageway for a plurality of heat transfer tubes to pass fluid through the wall of the reactor pressure vessel. The plurality of heat transfer tubes are connected to the plate.

A nuclear steam supply system having a start-up sub-system for heating a primary coolant. In one embodiment, the invention can be a nuclear steam supply system comprising: a reactor vessel having an internal cavity, a reactor core comprising nuclear fuel disposed within the internal cavity; a steam generating vessel fluidly coupled to the reactor vessel; a primary coolant loop formed within the reactor vessel and the steam generating vessel, a primary coolant in the primary coolant loop; and a start-up sub-system fluidly coupled to the primary coolant loop, the start-up sub-system configured to: (1) receive a portion of the primary coolant from the primary coolant loop; (2) heat the portion of the primary coolant to form a heated portion of the primary coolant; and (3) inject the heated portion of the primary coolant into the primary coolant loop.

A nuclear steam supply system having a shutdown system for removing residual decay heat generated by a nuclear fuel core. The steam supply system may utilize gravity-driven primary coolant circulation through hydraulically interconnected reactor and steam generating vessels forming the steam supply system. The shutdown system may comprise primary and secondary coolant systems. The primary coolant cooling system may include a jet pump comprising an injection nozzle disposed inside the steam generating vessel. A portion of the circulating primary coolant is extracted, pressurized and returned to the steam generating vessel to induce coolant circulation under reactor shutdown conditions. The extracted primary coolant may further be cooled before return to the steam generating vessel in some operating modes. The secondary coolant cooling system includes a pumped and cooled flow circuit operating to circulate and cool the secondary coolant, which in turn extracts heat from and cools the primary coolant.

This invention relates to electric power industry, and can be used in horizontal steam generators for nuclear power plants (NPP) with a water-water energetic reactor (VVER). We claim a steam generator primary circuit coolant header with U-shaped tubes of a horizontal heat-exchange bundle designed as a thick-wall welded vessel with a perforated central cylindrical part designed so as to allow installation and fastening of a U-shaped heat-exchange tube bundle in the same, wherein the tubes are grouped into banks and separated by vertical inter-tubular tunnels, a lower cylindrical part designed so as to allow welded connection with the steam generator vessel connection pipe, and an upper cylindrical part with a conical adapter to the flange connection of the manhole with a lid, wherein primary circuit header outer diameter D.sub.head in the central part is selected based on formula. The technical result of the invention involves assurance of strength of the header wall bridges between holes for fastening of heat-exchange tubes and leaktightness of heat-exchange tube connections with the header assuming that the outer surface of the perforated header part is more efficiently (fully) used for tubing.

A compact pressurized water nuclear reactor having connected to the reactor pressure vessel a plurality of pressure vessels connected by nozzles, and connected by curved horizontal pressure vessel heads by having their central axis horizontal, with reduced stress and simple single connection between the respective nozzle of the reactor pressure vessel with the respective nozzle of each curved horizontal pressure vessel heads, all with the same internal and external design pressure.

A nuclear steam supply system having a shutdown system for removing residual decay heat generated by a nuclear fuel core. The steam supply system may utilize gravity-driven primary coolant circulation through hydraulic-ally interconnected reactor and steam generating vessels forming the steam supply system. The shutdown system may comprise primary and secondary coolant systems. The primary coolant cooling system may include a jet pump comprising an injection nozzle disposed inside the steam generating vessel A portion of the circulating primary coolant is extracted, pressurized and returned to the steam generating vessel to induce coolant circulation under reactor shutdown conditions. The extracted primary coolant may further be cooled before return to the steam generating vessel in some operating modes. The secondary coolant cooling system includes a pumped and cooled flow circuit operating to circulate and cool the secondary coolant, which in tun extracts heat from and cools the primary coolant.

A nuclear steam supply system having a start-up sub-system for heating a primary coolant. In one embodiment, the invention can be a nuclear steam supply system comprising: a reactor vessel having an internal cavity, a reactor core comprising nuclear fuel disposed within the internal cavity; a steam generating vessel fluidly coupled to the reactor vessel; a primary coolant loop formed within the reactor vessel and the steam generating vessel, a primary coolant in the primary coolant loop; and a start-up sub-system fluidly coupled to the primary coolant loop, the start-up sub-system configured to: (1) receive a portion of the primary coolant from the primary coolant loop; (2) heat the portion of the primary coolant to form a heated portion of the primary coolant; and (3) inject the heated portion of the primary coolant into the primary coolant loop.

Disclosed herein is an apparatus for reactor power control of a steam turbine power generation system including a reactor, a high-pressure turbine to which steam is supplied from the reactor through a main steam pipe, a low-pressure turbine to which the steam discharged from the high-pressure turbine is supplied via a moisture separator reheater, a branch pipe branched from the main steam pipe to be connected to the moisture separator reheater, a generator connected to the low-pressure turbine, a condenser for condensing the steam discharged from the low-pressure turbine, a condensate pump for feeding condensate condensed by the condenser, and feed water heaters for heating the condensate, the apparatus including a branch pipe control valve provided on the branch pipe and a control unit for controlling an opening degree of the branch pipe control valve.