Nuclear reactor having double tube helical coil heat exchanger

A nuclear power plant comprising a nuclear reactor having a circulating liquid metal cooling system, which cooling system includes at least one heat exchanger comprising

• a vessel having a closed lower end, divided into at least three longitudinally arranged sections including an uppermost disengaging chamber suitable for collecting the products of a reaction between the liquid metal coolant and water, an upper plenum, and a lower plenum, said upper plenum being above said lower plenum and containing a plurality of double tube helical coils, wherein
• said cylindrical vessel is closed at its upper end by a closure plate having a plurality of feedwater inlet nozzles and steam outlet nozzles, the number of feedwater inlet nozzles being equal to the number of steam outlet nozzles, and each of said nozzles providing open communication to the outside of the cylindrical vessel;
• each double tube helical coil is comprised of 1-20 double tube bundles, each double tube bundle being comprised of 10-100 inner tubes individually enclosed for at least a portion of their length in an outer tube to form a double tube portion and thereby define an annular gap which is outside said inner tube and enclosed by said outer tube;
• said inner tubes being attached at one end to a feedwater inlet and attached at the other end to a steam outlet nozzle;
• said outer tubes being in open communication at both ends with said disengaging chamber, said disengaging chamber also having means for relieving gas pressure and for filling and draining the disengaging chamber and contiguous annular gaps;
• said annular gap being at least partially filled with liquid metal;
• each double tube portion extending from its end closest to the feedwater inlet connection of its inner tube downwardly to the bottom of said upper plenum, then spiraling upwardly in a helical configuration for at least a portion of the length of said upper plenum, the remainder of said double tube portion extending upwardly to its end closest to the connection of its inner tube with a steam outlet nozzle;
• said upper plenum having at least one liquid metal inlet in open communication with the outside of the cylindrical vessel, said upper plenum having no communication with said disengaging chamber and having restricted communication with said lower plenum such that liquid metal entering the upper plenum and flowing downwardly to said lower plenum closely contacts at least a portion of the double tube helical coil;
• said lower plenum having at least one liquid metal outlet in open communication with the outside of the cylindrical vessel;
• said double tube helical coil being enclosed by a cylindrical shroud extending the length of the upper plenum, the portion of said upper plenum outside said shroud being separated from said lower plenum by a diaphragm;
• the portion of said upper plenum outside said shroud being in communication with the portion enclosed by said shroud by means of a plurality of liquid metal distributor openings in said shroud, which liquid metal distributor openings are above the helix-shaped portion of said double tube helical coil.

A pool reactor comprising

• a vessel,
• a nuclear core which is cooled by a primary fluid,
• at least one heat exchanger for transferring heat from said primary fluid to a secondary fluid through an intermediate heat transfer fluid, said heat exchanger comprising
• a closed intermediate heat transfer fluid circuit comprising a disengaging chamber at each end of a helical coil portion, which helical coil portion is immersed in the primary fluid and wherein said intermediate heat transfer fluid circuit is partially filled with a stagnant intermediate heat transfer fluid which is compatible with said primary fluid, and
• a secondary fluid circuit which passes through the vessel and is substantially completely enclosed by said intermediate heat transfer fluid circuit,
• wherein said disengaging chamber is suitable for collecting the products of a reaction between the secondary fluid and the intermediate heat transfer fluid or primary fluid, and said disengaging chamber also has means for relieving gas pressure and for draining and filling the disengaging chamber and contiguous intermediate heat transfer fluid circuit.