Systems enhance stand pipe alignment and security with braces docking to the stand pipes. A link connects pairs of braces so the braces and stand pipes docked thereby cannot move relative to each other when fully secured. Partially securing braces allows adjustment of the braces and distance between the same and thus stand pipe position. Fully securing the braces makes the entire system rigid without need for a tie bar. Braces and links can be installed and secured to the stand pipes and among each other at an axial position from above the stand pipes, so that overhead, simple tooling may be used. A crimp nut or other resilient connector may be used to secure the systems from that single dimension with simple tooling. Any number of braces, joining to any number of other braces, may be used in the system, and several systems may be used at various levels.

A chimney structure according to a non-limiting example embodiment may include a guide structure defining an opening, and a plurality of chimney partitions including 1 to N chimney partitions concentrically arranged and spaced apart from each other on the guide structure. The 1 to N chimney partitions may each define a curved opening over the opening the guide structure. N may be an integer greater than 1.

A method of storing a chimney assembly of a reactor pressure vessel during a nuclear reactor outage includes detaching a chimney barrel with upper chimney partitions therein from a top guide assembly of the reactor pressure vessel. A height of the upper chimney partitions is less than a height of the chimney barrel so as to leave a plenum region in a top section of the chimney barrel. The top guide assembly includes lower chimney partitions therein. The lower chimney partitions are removed from the top guide assembly and inserted into the plenum region of the chimney barrel so as to be on the upper chimney partitions. As a result, the chimney assembly can be stored in a relatively compact form during a reactor outage. The chimney assembly includes a combination of at least the chimney barrel, the upper chimney partitions, and the lower chimney partitions.

A passive containment cooling and filtered venting system includes: an outer well; a scrubbing pool arranged in the outer well; a cooling water pool installed above the dry well and the outer well; a heat exchanger partly submerged in the cooling water; a gas supply pipe that is connected to the inlet plenum of the ruin of the heat exchanger at one end and connected to a gas phase region of the containment vessel at the other end; a condensate return pipe that is connected to the outlet plenum of the heat exchanger at one end, and connected to inside the containment vessel at other end; and a gas vent pipe that is connected to the outlet plenum of the heat exchanger at one end and is submerged in the scrubbing pool at other end.

A nuclear fuel assembly having varying spacing between fuel rods is provided. The nuclear fuel assembly includes a bundle of fuel rods. The fuel rods are arranged in a first lattice with a non-uniform pitch between the fuel rods in the lowermost section of the fuel assembly and in a second lattice with a uniform pitch between the fuel rods in the uppermost section of the fuel assembly.

A chimney arranged inside of a reactor pressure vessel of a natural-circulation boiling water reactor is provided. The chimney includes plural flow channels which guide a steam-water two-phase flow generated in a reactor core to the upper part of the reactor pressure vessel. Each of the flow channels is formed by plural flow channel separation walls whose lower-most part is supported by a chimney lattice plate. Chimney spacers that support a horizontal load are arranged between the flow channel separation walls of the adjacent flow channels. Chimney support rings that support the horizontal load are arranged at the outermost periphery of the plural flow channels that are supported by the chimney lattice plate.

The present invention discloses a heat exchange system and a nuclear reactor system. The heat exchange system includes: a heating device; a heat consuming device connected with the heating device through a pipe to form a loop; and a steam, which is in a wet steam state before being supplied to a heat source, and is supplied to the heat consuming device after becoming dry steam or superheated steam by exchanging heat with the heating device. Heat exchange efficiency and security of the nuclear reactor system are improved by adopting steam as a heat exchange medium.

Provided is a reactor that allows a fluid to easily flow. A reactor includes a reactor pressure vessel, a core provided in the reactor pressure vessel and loaded with a fuel assembly, and a steam-water separator provided in the reactor pressure vessel separates water and steam from a fluid containing the steam and the water generated in the core. The steam-water separator includes an annular flow channel through which the fluid flows from an upper side to a lower side and which opens to the lower side of the steam-water separator, and an opening that discharges air bubbles in the fluid flowing through the annular flow channel a side of the steam-water separator.

A method for retrofitting a nuclear power plant which include dismantling and removing all the components of the primary circuit apart from the LWR reactor vessel, which is essentially emptied of all material and neutralized, subsequently replacing a part of these components with subassemblies that are each made up of an integrated SMR reactor and a mixed concrete/metal structure, which mixed concrete/metal structure is also used as a reactor pit for the SMR reactor, which reactor pit is advantageously filled with water, anchoring the SMR to the inside of the reactor building and advantageously contributing to the third confinement barrier while ensuring minimal disruption to the infrastructure of the reactor building.