Abstract
A compact pressurized water nuclear reactor having connected to the reactor pressure vessel a plurality of horizontal pressure vessels, with all the horizontal pressure vessels connected to the reactor pressure vessel by a single connection between the respective nozzle of the reactor pressure vessel with the respective nozzle of each horizontal pressure vessel.
Claims
1. A compact pressurized water nuclear reactor characterized by having connected to the reactor pressure vessel a plurality of horizontal pressure vessels, with all the horizontal pressure vessels connected to the reactor pressure vessel by a single connection between the respective nozzle of the reactor pressure vessel with the respective nozzle of each horizontal pressure vessel.
2. A compact pressurized water nuclear reactor according to claim 1, characterized by being, the horizontal pressure vessels, horizontal steam generators, in which the primary coolant enters and leaves the reactor pressure vessel by internal flux dividers in the respective connection nozzle that separates both coolant streams.
3. A compact pressurized water nuclear reactor according to claim 1, characterized by being, one of the horizontal pressure vessels, a horizontal pressurizer, in which the primary coolant enters and leaves the reactor pressure vessel by a central channel in the respective nozzle connection.
4. A compact pressurized water nuclear reactor according to claim 1, characterized by being, one of the horizontal pressure vessels, a horizontal pressurizer, in which the primary coolant enters and exits to the horizontal pressurizer from and to the reactor pressure vessel by a central channel in the respective nozzle connection, and the other horizontal pressure vessels are horizontal steam generators, in which the primary coolant enters and leaves the reactor pressure vessel by internal flux dividers in the respective connection nozzle that separates both coolant streams.
5. A compact pressurized water nuclear reactor according to claim 1, characterized by having reactor coolant pumps directly connected to the upper side of the reactor pressure vessel, each one by a single nozzle that connects the respective reactor coolant pump to a respective side connection vessel, with an internal flux divider that separates the primary coolant that enters and leaves the reactor pressure vessel without mixing.
6. A compact pressurized water nuclear reactor according to claim 1, characterized by having reactor coolant pumps directly connected to the primary side of some horizontal pressure vessels, each one by a single nozzle that connects the respective reactor coolant pump with the primary side of the respective horizontal pressure vessel, with an internal flux divider that separates the primary coolant that enters and leaves the respective horizontal pressure vessel without mixing.
7. A compact pressurized water nuclear reactor according to claim 2, characterized by having reactor coolant pumps directly connected to the upper side of the reactor pressure vessel, each one by a single nozzle that connects the respective reactor coolant pump to the respective side connection vessel, with an internal flux divider that separates the primary coolant that enters and leaves the reactor pressure vessel without mixing.
8. A compact pressurized water nuclear reactor according to claim 2, characterized by having reactor coolant pumps directly connected to the primary side of each horizontal steam generators, each one by a single nozzle that connects the respective reactor coolant pump with the primary side of the respective horizontal steam generator, with an internal flux divider that separates the primary coolant that enters and leaves the respective primary side of the horizontal steam generator without mixing.
9. A compact pressurized water nuclear reactor according to claim 3, characterized by having reactor coolant pumps directly connected to the upper side of the reactor pressure vessel, each one by a single nozzle that connects the respective reactor coolant pump to the respective side connection vessel, with an internal flux divider that separates the primary coolant that enters and leaves the reactor pressure vessel without mixing.
10. A compact pressurized water nuclear reactor according to claim 3, characterized by having reactor coolant pumps directly connected to the primary side of the horizontal pressure vessels different from the horizontal pressurizer, each one by a single nozzle that connects the reactor coolant pump with the primary side of the respective horizontal pressure vessel, with an internal flux divider that separates the primary coolant that enters and leaves the respective primary side of the horizontal pressure vessel without mixing.
11. A compact pressurized water nuclear reactor according to claim 4, characterized by having reactor coolant pumps directly connected to the upper side of the reactor pressure vessel, each one by a single nozzle that connects the respective reactor coolant pump to the respective side connection vessel, with an internal flux divider that separates the primary coolant that enters and leaves the reactor pressure vessel without mixing.
12. A compact pressurized water nuclear reactor according to claim 4, characterized by having reactor coolant pumps directly connected to the primary side of each horizontal steam generator, each one by a single respective nozzle that connects the respective reactor coolant pump of the primary side of the respective horizontal steam generator, with an internal flux divider that separates the primary coolant that enters and leaves the respective primary side of the horizontal steam generator without mixing
13. A compact pressurized water nuclear reactor according to claim 1, characterized by having, each horizontal pressure vessel, supporting pads with horizontal sliding surfaces located at the same level than the midplane of the connection nozzle between the respective horizontal pressure vessel and the reactor pressure vessel, that transfer the loads to a rigid bottom support structure connected to the civil works and reactor basement, with clearances that allow to compensate the dimensional changes during normal operation and vertical up lift restrains for accidental conditions.
14. A compact pressurized water nuclear reactor according to claim 13, characterized by having, each horizontal pressure vessel, a horizontal key restrictor in the outer head of the horizontal pressure vessel that allows axial movements, restricts lateral and vertical movements, and is located at the same level of the midplane of the connection nozzle between the respective horizontal pressure vessel and the reactor pressure vessel.
15. A compact pressurized water nuclear reactor according to claim 2, characterized by having, each horizontal steam generator, supporting pads with horizontal sliding surfaces located at the same level than the midplane of the connection nozzle between the respective horizontal steam generator and the reactor pressure vessel, that transfer the loads to a rigid bottom support structure connected to the civil works and reactor basement, with clearances that allow to compensate the dimensional changes during normal operation and vertical up lift restrains for accidental conditions.
16. A compact pressurized water nuclear reactor according to claim 15, characterized by having, each horizontal steam generator, a horizontal key restrictor in the outer head of the horizontal pressure vessel that allows axial movements, restricts lateral and vertical movements, and is located at the same level of the midplane of the connection nozzle between the respective horizontal pressure vessel and the reactor pressure vessel.
17. A compact pressurized water nuclear reactor according to claim 3, characterized by having, the horizontal pressurizer, supporting pads with horizontal sliding surfaces located at the same level than the midplane of the connection nozzle between the respective horizontal steam generator and the reactor pressure vessel, that transfer the loads to a rigid bottom support structure connected to the civil works and reactor basement, with clearances that allow to compensate the dimensional changes during normal operation and vertical up lift restrains for accidental conditions.
18. A compact pressurized water nuclear reactor according to claim 17, characterized by having, the horizontal pressurizer, a horizontal key restrictor in the outer head of the horizontal pressure vessel that allows axial movements, restricts lateral and vertical movements, and is located at the same level of the midplane of the connection nozzle between the respective horizontal pressure vessel and the reactor pressure vessel.
19. A compact pressurized water nuclear reactor according to claim 4, characterized by having, each horizontal steam generator and the horizontal pressurizer, supporting pads with horizontal sliding surfaces located at the same level than the midplane of the connection nozzle between the respective horizontal steam generator and pressurizer with the reactor pressure vessel, that transfer the loads to a rigid bottom support structure connected to the civil works and reactor basement, with clearances that allow to compensate the dimensional changes during normal operation and vertical up lift restrains for accidental conditions.
20. A compact pressurized water nuclear reactor according to claim 17, characterized by having, each horizontal steam generator and the horizontal pressurizer, a horizontal key restrictor in the outer head that allows axial movements, restricts lateral and vertical movements, and is located at the same level of the midplane of the connection nozzle between the respective horizontal pressure vessel and the reactor pressure vessel.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0067] To better understand this disclosure, provided below is a detailed description on the basis of the following figures, which serve the sole purpose of illustrating the preferred way to execute this patent and not to represent a limit to the disclosure:
[0068] FIG. 1 is a perspective view of a compact PWR with the design proposed with two horizontal SGs connected by nozzles, and four RCP connected by nozzles and side connection vessels.
[0069] FIG. 2 is a side elevational cross-sectional partial view of the design shown in FIG. 1.
[0070] FIG. 3 is a perspective partial view of a vertical section of the RPV of the design shown in FIG. 1 to show the flux dividers that connect the cold water exit from one SG with the inlet of two RCP.
[0071] FIG. 4 is a perspective view of a compact PWR with the design proposed with two horizontal SGs connected by nozzles and two RCP connected by nozzles directly in the primary side of the horizontal SG vessel head.
[0072] FIG. 5 is a side elevational view in cross section view of the drawing shown in FIG. 4.
[0073] FIG. 6 is a perspective view of a compact PWR with the design proposed with four horizontal SG with four RCP connected to the RPV, showing the support pads and restrictors that transfer the loads to the support and basement and minimize the load during earthquakes.
[0074] FIG. 7 is a perspective view of a compact PWR with the design proposed with three horizontal SGs connected by nozzles, three RCP connected by nozzles directly to side connection vessels and a horizontal pressurizer.
[0075] FIG. 8 is a side elevated view of a portion of the design shown in FIG. 7.
DETAILED DESCRIPTION OF THE DISCLOSURE
[0076] Prior to proceeding with a detailed description, note that the described execution is not restricted to being used together with a specific type of nuclear reactor. Therefore, even when for explanatory convenience this execution is shown and described as applied to a compact PWR, it may be implemented on other types of nuclear reactors, as well as on other systems and environments.
[0077] This disclosure presents a new design design compact PWR that yields a compact, light, simple, and economic reactor, as well as one that is easy to maintain, operate and to refuel, without weak points regarding earthquakes, thermal stress, stratifications or complex support structures.
[0078] FIG. 1 is an external view of a compact PWR with the design proposed in which the RPV (10) with its closure head (12) its fixed to the vessel by bolts and nuts not shown in the picture, with two horizontal SGs (14) and (16), in this case with an external pressurizer (20) connected with the primary system with the surge line (22) which is in the range of a medium size pipe diameter. The horizontal SGs (14) and (16) are connected to the RPV (10) by nozzles, as is shown by the nozzle (25) without using pipes for the connection, by welding the respective RPV nozzle with the SG nozzle located in the primary side head of the SG. The four RCP (30) (40) (50) and (60) that drive the primary coolant have a vertical orientation and are connected with the RPV (10) by a nozzle directly connected to a side connection vessels (70) (72) and (74). The side connection vessel (70) connects the RCP (50) with the RPV (10), and the other side connection vessels (72) and (74) connect the respective RCPs (60) and (30) with the RPV (10). The RPCs (30) (40) (50) and (60) could be oriented in horizontal or in an intermediate angular inclination with respect to the vertical direction if it's convenient by its weight and size and in this case the connection with the RPV (10) could be done without side connection vessels (70) (72) and (74), if its required.
[0079] FIG. 2 is a schematic vertical section view of the design shown in FIG. 1, with the core (100) cooled by the ascendant cooling flow shown as a schematic arrow (102). The cooling flow crosses the zone of the control rod guide structure (105) up to an upper plenum (110). During the ascending trajectory, the coolant flow is surrounded by a cylindrical watertight flux divider (112) core barrel up the upper plenum to turn, as shown by the arrow (113), towards the SG inlet (115) that guides the coolant flow towards the inlet zone (118) of the primary side SG head. The coolant flow crosses the SG tube sheet (120), as is schematically shown by the arrow (122), to circulate through the horizontal U tube bundle (125), which are not individually shown in the figure, in horizontal direction and descends and returns to the outlet zone (130) of the primary side SG head after crossing the exit region of the tube sheet (120), as shown by the schematic arrow (132). The coolant flow is guided by the shell (135), as schematically shown by the arrow (137), towards the RPV to be guided by the flow separators (140) towards the RCP inlet, not shown in this view. The vertical RCP (150) and (155) discharge the coolant exit to the down corner (160) limited by the core barrel (112) and the RPV (170). The coolant flow descends, as shown by the schematic arrows (163) and (165), towards the lower plenum (180) prior to entering to the reactor core (100) to complete the primary coolant circuit. The coolant flow in the upper plenum (110) that is not directed towards the SG inlet (115) is directed towards the second SG tube bundle (175) to circulate in a similar way to the circulation in the tube bundle (125) and discharge the coolant exit to the common upper plenum (160) of the coolant down corner.
[0080] FIG. 3 is an external view of a vertical section of the RPV of the design shown in FIG. 1, in which the core barrel is not shown to visualize the coolant inlet and outlet of the SG. The RPV (200) and its vessel closure head (210) are shown to visualize the SG inlet guide annular channel (212), as shown by the schematic arrows (214) and (216), towards the SG (218) to return after being cooled by the water of the secondary circuit, through the central channel (220) to be redirected horizontally through the pipes (222) and (224), as shown by the schematic arrow (226), to be guided by the pipes (230) and (232), as shown schematically by the arrows (234) and (236), towards the central zone of the side connection vessels (240) and (245), towards the RCPs (250) and (255). The RCP discharge returns through the annular space (260) and (262), as is schematically shown by the arrows (264) and (266), discharging the coolant flow in the down corner limited by the RPV (200) and the core barrel not shown in the picture, to descends towards the core inlet, as is schematically shown by the arrows (270) and (275).
[0081] FIG. 4 is an external view of a compact PWR with the design proposed with two horizontal SGs and two RCPs, in which the RPV (300) is shown with its closure head (310) and two horizontal SGs (320) and (325). The horizontal SGs (320) and (325) are connected to the RPV (300) with nozzles (330) and (335) without using pipes in the connection, connecting directly the RPV (300) with the primary side heads (340) and (345) of the horizontal SGs (320) and (325). The vertical RCPs (350) and (360) are connected directly to the primary side heads (340) and (345) of the horizontal SGs (320) and (325).
[0082] FIG. 5 is a lateral schematic vertical section view of the design shown in FIG. 4, with the core (400) cooled by the ascendant cooling flow that crosses the zone of the control rod guide structure (405) up to an upper plenum (410). During the ascendant trajectory the coolant flow is surrounded by the watertight core barrel (415) until it reaches the SG water inlet (420) that guides the coolant flow towards the primary side SG inlet head (425), crosses the inlet section of the SG tube sheet (430), flows through the horizontal U tube bundle (440), which are not individually shown in the picture, in horizontal direction, and descends and returns to the outlet zone (445) of the primary side SG head after crossing the exit region of the tube sheet (430). The coolant flow is guided by the chamber (450), as schematically shown by the arrow (455), which feeds the centrifugal impeller, which is not shown in the picture, of the RCP (457). The RCP (457) discharges the coolant through the volute casing (460) to the pump exit, as schematically shown by the arrow (467), and circulates by the pipe (465) towards the lateral flow distributor (470) that discharges the coolant to the down corner (480) created by the core barrel (415) and the RPV (485) and reaches the lower plenum (490) and enters the core (400) to complete the primary coolant circuit. As the figure shows, the height of the overall primary coolant circuit, composed by the RPV (485) and the SGs and RPC (457), is much lower than the conventional and compact PWR layout, because the horizontal SG and RCP do not require higher elevation than the RPV, thus the height of the reactor containment building could be strongly reduced compared with other compact PWR, thus easier and less expensive to be underground y to reduce the risk of aircraft crashes together with reduce the building stress for seismic loads.
[0083] FIG. 6 is an external view of a compact PWR with the design proposed with four horizontal SG with four RCP. The RPV (500) is connected with each horizontal SG (510) (512) (514) and (516) and each RCP (520) (522) (524) and (526) by nozzles. The horizontal SGs are supported by a plurality of support pads, as shown by the GV support pad (530), in a similar way as is supported the RPV which is supported by a plurality of support pads, as shown by the RPV support pad (535). All the plurality of supports pads are located at the same height of the horizontal mean plane of each SG connection nozzle, and each support pad transfers the weight load to a respective support structure, like the support structure (540), through a sliding surface that allows thermal and pressure related transversal and longitudinal dimensional changes. Each combination of support pad and support structure includes conventional up lift restrictors, not shown in the figure, for accidental conditions. The combination of all the support beams transfers the weight load to a common support structure (545) that transfers the load to the civil works and the reactor basement, not shown in the figure. Each SG has a sliding key in the outer head, as the sliding key (550) that is limited by lateral, top and bottom restrictor (555) that allows axial growing of the SG and radial growing of the RPV, but limits the lateral and vertical SG movement by horizontal and vertical seismic and accidental responses. With the SG center of gravity close to the sliding surface between the support pads and support structures, and the middle plane of the each respective nozzle in combination with the outer sliding key in each GV produce minimal loads against earthquakes in both vertical and horizontal combination, reducing the stress in nozzles in accidental conditions.
[0084] FIG. 7 is an external view of a compact PWR with the design proposed with three horizontal SGs connected, three RCP and a horizontal pressurizer, in which the RPV (600) is connected with single respective nozzles to each respective horizontal SG (610) (612) and (614). The external view allows to identify the three connection nozzles (620) (622) and (624) to each SG. The external view also allows to see the RCP (630) (632) and (634) connected to the RPV (600) by the corresponding side connection vessels (640) (642) and (644). The horizontal pressurizer (650) has an upper dome (655) where are located the connection nozzles with the relief pipes and pressurizer water spray, shown as the nozzles (660) (662) (664) (665) (667) and (669). The horizontal pressurizer is connected with the RPV by a nozzle, without using a surge line, and is supported by support pads as the shown by (672) and (674), which are located at the same horizontal plane of the connection nozzle, which is also close to the center of gravity of the pressurizer and the support plane of the GVs (680) (682) and (684). The pressurizer has a sliding key in the outer head (690) that is limited by lateral, top and bottom restrictor, not shown in the picture, that allows axial growing of the pressurizer and radial growing of the RPV, but limit the lateral and vertical SG movement by horizontal and vertical seismic and accidental responses, which is similar to the SG sliding keys (692) and (694). This horizontal pressurizer (650) does not require higher elevation compared with SG (610) (612) and (614), not demanding a higher reactor containment building than the height required for all the other components of the primary circuit.
[0085] FIG. 8 is a lateral schematic vertical section view of the design shown in FIG. 7, showing a vertical section of the RPV (700) and the horizontal pressurizer (710), and the connection between the RPV (700) and the pressurizer (710) by a single nozzle made by a welded union of the two nozzles (712) and (714) with a central channel (716) to not use pipe o surge line for the connection. The liquid level in the pressurizer is schematically shown by the level (720) which is thermally decoupled from the central channel (716) by a watertight descending thermal insulation panel (730) in the section close to the central channel (716), and is horizontal insulation panel (735) and not watertight for a plurality of small equalization holes that connect the volume of water in the bottom of the pressurizer (740) with the water volume (750) between the liquid level (720) and the horizontal thermal isolation panel (735). The water volume (750) is at higher temperature than the water in the volume in the bottom of the pressurizer (740) by a plurality of horizontal electric heaters, as the heaters (770) and (772). Then there is a large temperature difference produced by the thermal stratification of the water volume (750) above the heaters and the pressurizer bottom water (740) level below the thermal insulation (735). During operation, the heated water volume (750) is at saturation temperature at the pressure of the steam volume (780), which is above the liquid level (720). The small heat transfer from the heated water volume (750) through the thermal insulators (730), which is compensated by a small water flow of cold water not shown in the figure, enters to the pressurizer in the watertight zone (760) of the thermal insulator (730). A small water flow through the equalization holes of the horizontal thermal insulator (735), and the inherent thermal stratification between the upper hot water zone and the lower cold water zone ensure a much lower temperature for the water volume (740) at the bottom of the pressurizer, compared with the temperature of the heated water volume (750) which is at saturation temperature at the pressure of the steam volume (780). During normal operation the temperature difference between the cold water volume (740) and the hot water volume (750) is about 50 or more degrees Fahrenheit. This thermal stratification and pressure equalization process in the pressurizer (710) pressurize the water circuit of the RPV (700) through the connection (716) that connects the water flow that leaves the core (785) and the corresponding water sub cooling for the water flow that enters the reactor core. The pressure of the reactor primary cooling circuit is controlled by controlling the pressure of the steam dome (780) above the liquid level (720). This control is performed by increasing or decreasing the current through the plurality of electric heaters, as the heaters (770) and (772), by a sub cooled water spray in the steam dome by spray nozzles, as the spray nozzle (790), which is located at the top of the steam dome (780), and by pressure relief valves, not shown in the picture, connected to relief nozzles located at the top of the steam dome (780) as the nozzles (792) and (794).
[0086] The exemplary embodiment has been described with reference to the preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the exemplary embodiment be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
