Submerged nuclear power station

Abstract

A self-contained, offshore, underwater nuclear power plant is housed within a hull mounted to the seafloor. An electric line extends from the offshore power plant to an onshore electric load to power the electric load. The body of water provides a heat sink for the power plant, and protection from surface weather, waves, and currents. The hull mounts to the seafloor via a dampener that reduces the transfer of seismic activity from the seafloor to the hull. The hull and power plant may be manufactured at an onshore facility and transported to an offshore location of operation on the seafloor. After completion of a fuel cycle, the hull and power plant may be transported from the offshore location of operation to an onshore maintenance / refueling facility for refueling, repair and later, when obsolete or damaged, for decommissioning.

Description

SUBMERGED NUCLEAR POWER STATIONCROSS REFERENCE

[0001] This application claims the benefit of priority from U.S. Provisional Patent Application Serial No. 63 / 736,933, filed December 20, 2024, titled “SUBMERGED NUCLEAR POWER STATION,” the entire contents of which are hereby incorporated herein by reference herein.BACKGROUND1. Field

[0002] Various embodiments relate generally to offshore nuclear power stations.2. Description of Related Art

[0003] Nuclear power plants have been placed on ships and in submarines to provide onboard power. Floating nuclear power plants are also known, e.g., the Russian Akademik Lomosov, to provide power to onshore electricity users.SUMMARY

[0004] This section is for the purpose of summarizing some aspects of various embodiments and to briefly introduce some preferred embodiments. Nothing in this section is intended to limit the scope of any invention disclosed herein.

[0005] One or more non-limiting embodiments provide a self-contained, offshore, submerged nuclear power plant mounted to the seafloor well below the surface of the surrounding body of water (e.g., sea, ocean, lake). The power plant uses the ambient seawater as a heat sink. The power plant may be deployed sufficiently deep to minimize the impact of surface weather (e.g., hurricanes) and surface currents. The power plant may be mounted to the seafloor via vibration dampeners that reduce the transfer of seismic activity (e.g., earthquakes) from the seafloor to the hull.

[0006] One or more non-limiting embodiments provides a power station comprising: a submersible hull defining an interior; a nuclear power plant comprising a nuclear reactor disposed in the interior; an output electric line extending from the power plant and configured to transferelectricity generated by the power plant to an electric load outside the hull; and at least one connector configured to mount the hull to a seafloor of a body of water such that the hull is submerged within the body of water.

[0007] According to various embodiments, the hull, including all material in the interior, is negatively buoyant.

[0008] During use, the hull is submerged within the body of water.

[0009] According to various embodiments, the hull has an effective density DH, the water in the body of water has a density DW, and (l.OOlxDW) < DH < (1.05xDW).

[0010] According to various embodiments, the at least one connector comprises at least one strut configured to operate in both tension and compression.

[0011] According to various embodiments, the at least one strut comprises at least one dampener configured to dampen a transfer of seismic movement from the seafloor to the hull in both tensile and compressive directions.

[0012] According to various embodiments, the at least one strut is shaped and configured to support the hull such that the hull remains spaced from the seafloor.

[0013] According to various embodiments, the at least one strut comprises a plurality of struts each having a first end mounted to the hull and a second end mounted to the seafloor.

[0014] According to various embodiments, the power station further comprises at least one base plate mounted to the seafloor. The second ends of the struts mount to the seafloor via the at least one base plate.

[0015] According to various embodiments: the hull defines a pressure boundary separating the power plant from an ambient environment outside the hull; and the pressure boundary prevents water from crossing the pressure boundary.

[0016] According to various embodiments, the interior is configured to contain fresh water to act as a shielding material and heat sink for the power plant.

[0017] According to various embodiments, the interior is configured to contain an inert gas with a low enough oxygen concentration to act as a fire suppressant.

[0018] According to various embodiments, the power station further comprises a control center outside the hull and operatively connected to the power plant to facilitate human monitoring and control of the power plant from outside the hull.

[0019] According to various embodiments, the control center operatively connects to the power plant via a hardwired connection and a back-up wireless connection.

[0020] According to various embodiments, the control center is on shore, on a floating vessel, or above a surface of the body of water on a support structure mounted to the seafloor.

[0021] According to various embodiments: the electric load comprises an onshore electric load, and the output electric line is configured to extend from the power plant to the onshore electric load to provide electricity to the onshore electric load.

[0022] According to various embodiments, the power plant comprises: a reactor vessel having a core comprising fissile material; a steam generator; a primary coolant loop extending between the reactor and the steam generator; at least one turbine having an output shaft; a secondary coolant loop extending between the steam generator and the at least one turbine; and an electric generator having an input shaft operatively connected to the output shaft. The reactor is configured to heat a primary coolant flowing through the primary coolant loop. The steam generator is configured to transfer heat from the primary coolant to secondary coolant in the secondary coolant loop, thereby causing the secondary coolant to form steam. The secondary coolant loop is configured to circulate steam through the at least one turbine, thereby spinning the turbine, output shaft, and input shaft to generate electricity.

[0023] According to various embodiments: the steam generator comprises a tube and shell steam generator in which the primary coolant loop passes through tubes of the steam generator; the secondary coolant loop passes between the shell and the tubes; and the tubes extends horizontally such that the steam generator is a horizontal steam generator.

[0024] According to various embodiments, the power station further comprises: a condenser, wherein at least a portion of the secondary coolant loop extends through the condenser; and a tertiary coolant loop extending between an ambient environment outside the hull and the condenser. The condenser is configured such that at least a portion of the secondary coolant exiting the at least one turbine circulates through the condenser, which transfers heat from the secondary coolant into water in the tertiary coolant loop and then into the body of water.

[0025] One or more embodiments provide a method of using an embodiment of such a power station. The method comprises: transporting the hull to an offshore site; mounting the hull to the seafloor via the at least one connector such that the hull is submerged at an offshore location ofoperation; generating electricity using the power plant; and transferring electricity generated by the power plant to the electric load via the output electric line.

[0026] According to various embodiments, the electric load is located on shore, and the hull is disposed offshore during said generating and transferring.

[0027] According to various embodiments, said mounting comprises mounting the hull at least partially within a human-made depression in the seafloor.

[0028] According to various embodiments, said mounting results in the entire power plant and hull being at least 25 meters under a surface of the body of water.

[0029] According to various embodiments, the method further comprises, after said generating and transferring: unmounting the hull from the seafloor; transporting the hull to an onshore refueling facility; at the refueling facility, removing spent fissile fuel from the reactor, and replacing the spent fuel with fresh fissile fuel; transporting the hull to the offshore location of operation for the power plant or a second offshore location of operation for the power plant; mounting the hull to the seafloor at the offshore location of operation such that the hull is disposed below the surface of the body of water; generating electricity using the power plant; and transferring electricity generated by the power plant to the electric load or a second electric load via the output electric line.

[0030] One or more of these and / or other aspects of various embodiments of the present application, as well as the methods of operation and functions of the related elements of structure and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures. In one or more embodiments, the structural components illustrated in the drawings are drawn to scale. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the present disclosure. In addition, it should be appreciated that structural features shown or described in any one embodiment herein can be used in other embodiments as well. As used in the specification and in the claims, the singular form of “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise.

[0031] All closed-ended (e.g., between A and B) and open-ended (greater than C) ranges of values disclosed herein explicitly include all ranges that fall within or nest within such ranges. Forexample, a disclosed range of 1-10 is understood as also disclosing, among other ranges, 2-10, 1-9, 3-9, etc. Similarly, where multiple parameters (e.g., parameter C, parameter D) are separately disclosed as having ranges, the embodiments disclosed herein explicitly include embodiments that combine any value within the disclosed range of one parameter (e.g., parameter C) with any value within the disclosed range of any other parameter (e.g., parameter D).

[0032] Various examples are described and illustrated herein to provide an overall understanding of the structure, function, and use of the disclosed articles and methods. The various examples described and illustrated herein are non-limiting and non-exhaustive. Thus, an invention is not limited by the description of the various non-limiting and non-exhaustive examples disclosed herein. Rather, the invention is defined solely by the claims. The features and characteristics illustrated and / or described in connection with various examples may be combined with the features and characteristics of other examples. Such modifications and variations are intended to be included within the scope of this specification. As such, the claims may be amended to recite any features or characteristics expressly or inherently described in, or otherwise expressly or inherently supported by, this specification. Further, Applicant reserves the right to amend the claims to affirmatively disclaim features or characteristics that may be present in the prior art. The various embodiments disclosed and described in this specification can comprise, consist of, or consist essentially of the features and characteristics as variously described herein.

[0033] Any references herein to “various embodiments,” “some embodiments,” “one embodiment,” “an embodiment,” or like phrases mean that a particular feature, structure, or characteristic described in connection with the example is included in at least one embodiment. Thus, appearances of the phrases “in various embodiments,” “in some embodiments,” “in one embodiment,” “in an embodiment,” or like phrases in the specification do not necessarily refer to the same embodiment. Furthermore, the particular described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Thus, the particular features, structures, or characteristics illustrated or described in connection with one embodiment may be combined, in whole or in part, with the features, structures, or characteristics of one or more other embodiments without limitation. Such modifications and variations are intended to be included within the scope of the present embodiments.

[0034] In this specification, unless otherwise indicated, all numerical parameters are to be understood as being prefaced and modified in all instances by the term “about,” in which thenumerical parameters possess the inherent variability characteristic of the underlying measurement techniques used to determine the numerical value of the parameter. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter described herein should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0035] Also, any numerical range recited herein includes all sub-ranges subsumed within the recited range. For example, a range of “1 to 10” includes all sub-ranges between (and including) the recited minimum value of 1 and the recited maximum value of 10, that is, having a minimum value equal to or greater than 1 and a maximum value equal to or less than 10. Any maximum numerical limitation recited in this specification is intended to include all lower numerical limitations subsumed therein and any minimum numerical limitation recited in this specification is intended to include all higher numerical limitations subsumed therein. Accordingly, Applicant reserves the right to amend this specification, including the claims, to expressly recite any sub-range subsumed within the ranges expressly recited. All such ranges are inherently described in this specification.

[0036] The grammatical articles “a,” “an,” and “the,” as used herein, are intended to include “at least one” or “one or more,” unless otherwise indicated, even if “at least one” or “one or more” is expressly used in certain instances. Thus, the foregoing grammatical articles are used herein to refer to one or more than one (i.e., to “at least one”) of the particular identified elements. Further, the use of a singular noun includes the plural and the use of a plural noun includes the singular, unless the context of the usage requires otherwise.BRIEF DESCRIPTION OF THE DRAWINGS

[0037] For a better understanding of various embodiments as well as other objects and further features thereof, reference is made to the following description which is to be used in conjunction with the accompanying drawings, where:

[0038] FIG. l is a diagrammatic view of a submerged nuclear power station at a location of operation on the seafloor, according to one or more embodiments.

[0039] FIG. 2 is a diagrammatic side view of the power station shown in FIG. 1;

[0040] FIG. 3 is a diagrammatic end view of the power station shown in FIG. 1;

[0041] FIG. 4 is a side view of support struts of the power station shown in FIG. 1;

[0042] FIG. 5 is a diagrammatic side view of a strut shown in FIG. 4;

[0043] FIG. 6 is a diagrammatic view of steam cycle and coolant loops of the power station shown in FIG. 1 ;

[0044] FIG. 7 is a diagrammatic top view of a fabrication and refueling facility for the power station shown in FIG. 1; and

[0045] FIGS. 8-10 are sequential side views showing the operation of a power station transfer lock of the facility in FIG. 7; and

[0046] FIG. 11 is a diagrammatic end view of the lock of FIGS. 8-10.DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0047] As shown in FIG. 1, a nuclear power station 10 includes a nuclear power plant 100 and a hull 20 submerged in a body of water 30. The hull 20 mounts to the seafloor 40 via a plurality of struts 50. Many components of the nuclear power plant 100 are housed within an interior 20a of the hull 20. The body of water 30 provides a heat sink for the power plant 100 and protection against adverse weather at the surface (e.g., storms). The struts 50 suspend the hull 20 above the seafloor 40 and protect the hull 20 from seismic activity. An output electric line 60 extends from the power plant 100 to an electric load 70 to transfer electricity generated by the power plant 100 to the electric load 70.

[0048] Hull 20

[0049] As shown in FIGS. 1-3, the hull 20 is generally cylindrically shaped with hemispherically shaped ends. However, the hull 20 may have any other suitable shape without deviating from the scope of the invention. According to one or more embodiments, the hull 20 comprises steel. The hull 20 defines a pressure boundary 20b that separates the interior 20a from the ambient water of the body of water 30 surrounding the hull 20. The pressure boundary 20b prevents water from moving into or out of the interior space 20a.

[0050] As shown in FIG. 2, ballast tank(s) 80 may be disposed in or on the hull 20. The ballast tank(s) 80 may be selectively filled with ambient water from the body of water 30 or displaced by a gas so as to actively control the buoyancy of the hull 20. When mounted to the seafloor 40, the hull 20 is preferably slightly negatively buoyant relative to a density DW of the body of water such that the hull 20 tends to sink. This slightly negative buoyancy tends to reduce stress on the struts 50 holding the hull 20 in place at an offshore location of operation 85 of the hull20 and power plant 100 on the seafloor 40. The hull 20 has an effective density DH, which accounts for the mass and displacement of everything mounted on or in the hull 20, including ballast in the tank(s) 80, but excluding the struts 50 and portions of the line 60, 710 outside the hull 20.

[0051] According to various embodiments, when mounted to the struts 50 and seafloor 40, the hull 20 is slightly negatively buoyant such the hull 20 will tend not to float to the surface if the supports fail. For example, according to various embodiments, DH is (a) at least 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, and / or 5% larger than DW, (b) no more than 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.25, 0.2, 0.1, and / or 0.01 % larger than DW, (c) and / or between any two such upper and lower boundaries (e.g., 0.01-5% denser than DW, 0.1-5% denser than DW (l.OOlxWD < DH < 1.05xDW), 0.1-2% denser than DW, 0.5-1.5% denser than DW, 0.1-0.3% denser than DW, -0.2% denser than DW, -0.1% denser than DW, -1% denser than DW). However, according to various alternative embodiments, the hull 20, even when mounted in its location of operation 85 and operating, is slightly buoyant such that DH is (a) at least 0.01, 0.1, 1, 2, 3, 4, and / or 5% smaller than DW, (b) no more than 10, 9, 8, 7, 6, 5, 4, 3, 2, and / or 1 % smaller than DW, (c) and / or between any two such upper and lower boundaries (e g., between 0.01 and 5% smaller than DW). According to various embodiments, the ballast tank(s) 80 and / or tanks 330 may be actively filled or emptied so as to control the buoyancy of the hull 20 during transportation of the hull 20 between the location of operation 85 on the seafloor 40 (shown in FIG. 1) and an onshore maintenance facility 1000 (shown in FIG. 7).

[0052] According to various embodiments, hull 20, as deployed in its operative location 85 on the seafloor 40 has a displacement of (a) at least 1000, 2500, 5000, 7500, 10000, 12500, 15000, 17500, 20000, 22500, 25000, 27500, 3000, 3500, 4000, 4500, and / or 5000 tons, (b) no more than 75000, 70000, 65000, 60000, 55000, 50000, 45000, 40000, 35000, 30000, 27500, 25000, 22500, 20000, 17500, 15000, 12500, 10000, 7500, 5000, and / or 2500 tons, and / or (c) between any two such values (e.g., 1000-75000 tons, 15000-75000 tons, 20000-30000 tons, -25 tons).

[0053] According to one embodiment, the displacement of the hull 20 is about 26,000 tons, and the hull 20 is 0.2% denser than DW, which results in a cumulative weight of about 500 kN resting on the struts 400.

[0054] The interior space 20a includes a reactor chamber 20d that houses the shielding plenum 150 and reactor vessel 110. The chamber 20d around the plenum 150 and reactor vessel 110 may be partially or completely filled with fresh water 90 (e.g., distilled water) to act as a shieldingmaterial and heat sink for the power plant 100. According to various embodiments, water (e.g., fresh water 90 within the reactor chamber 20d and borated water 140 within the shielding plenum 150 ) is the primary shielding material for the core 120 and reactor vessel 110. According to various embodiments, concrete is not used within the hull 20 as a shielding material.

[0055] A non-water-fdled volume within the interior 20a (including the reactor chamber 20d and a power generation space 20c) may be partially or completely fdled with an inert gas 95 (e.g., nitrogen) with a low-enough oxygen concentration to act as a fire suppressant (e.g., oxygen concentration less than 16, 15, 14, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, and / or 1%, ~ 5%).

[0056] According to various embodiments, the hull 20 has a longitudinal length, as measured along it longest direction (axial direction in the embodiment shown in the figures) of (a) at least 20, 30, 40, 50, 60, 70, and / or 80 meters, (b) no more than 200, 190, 180, 170, 160, 150, 140, 130, 120, 110, 100, 90, 8, 70, 60, 50, 40, and / or 30 meters, and / or (c) between any two such limits (e.g., 80-140 meters, 20-200 meters, 30-130 meters, 50-110 meters, ~ 80 meters).

[0057] According to various embodiments, the hull 20 has a width (e.g., diameter for a cylindrically shaped hull 20), as measured perpendicularly to the longitudinal direction, of (a) at least 5, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, and / or 25 meters, (b) no more than 50, 40, 35, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, and / or 11 meters, and / or (c) between any two such limits (e.g., 5-50 meters, 10-30 meters, 15-25 meters, ~ 20 meters).

[0058] Power Plant 100

[0059] As shown in FIGS. 2 and 6, the power plant 100 comprises a pressurized water reactor (PWR). However, according to various alternative embodiments, the power plant 100 may comprise any other type of suitable reactor without deviating from the scope of the invention (e.g., boiling water reactor (BWR), heavy water reactor, high temperature gas-cooled reactor, lead-cooled fast reactor). The PWR power plant 100 comprises a thermally insulated reactor vessel 110 having a core 120 comprising fissile material, a control rod and drive mechanism 130, a borated water 140 filled shielding plenum 150 surrounding the reactor vessel 110 and control rod mechanism 130, two steam generators 160, a primary coolant loop 170 extending between the reactor vessel 110 and the steam generators 160, one or more high pressure turbines 200 having one or more output shafts 200a, one or more low pressure turbines 210 having one or more output shafts 210a, an auxiliary turbine 215, a secondary coolant loop 220 extending between the steam generators 160 and the turbines 200, 210, one or more feedwater pumps 230 disposed in the secondary coolant loop 220downstream from the turbine(s) 200, 210 to pump liquid coolant back to the steam generators 160, one or more feedwater heaters 240 disposed in the secondary coolant loop 220 downstream from the turbine(s) 200, 210 to heat the liquid secondary coolant in the loop 220, a condenser 250 disposed in the secondary coolant loop 220 downstream from the low pressure turbine(s) 210, a condensate pump 260 disposed in the secondary coolant loop 220 downstream from the condenser 250, a tertiary coolant loop 270 extending between an ambient environment outside the hull 20 and condensers 250, and one or more electric generators 280 having an input shaft 280a operatively connected to the output shafts 200a, 210a, control and power conditioning equipment 290, accumulators 300, primary coolant pump(s) 310, and a missile shield 320 above the control rod mechanism 130.

[0060] According to various embodiments, the combination of borated water 140 and shielding fresh water 90 surrounding the reactor vessel 110 may comprise about 3600 tons of water.

[0061] According to various embodiments, freshwater tanks 330 may be disposed within the power generation space 20c or any other available space within the interior 20a (e g., within the spherical end caps (e g., within the ballast tanks 80)). As shown in FIG. 2, one or more such freshwater tanks 330 may be disposed under the turbines 200, 210 and / or generator(s) 280. The tanks 330 may be filled with fresh water that is used as service water, for example to cool equipment (e.g., generator(s) 280, control and power conditioning equipment 290, etc.). According to various embodiments, service water from the tanks 330 may additionally or alternatively be used to absorb the heat of primary coolant during a reactor blowdown, to be an intermediate heat sink during a Loss of Coolant Accident (LOCA), and / or to establish about 1% negative buoyancy when the hull 20 is in normal operation. According to various embodiments, the tanks 330 may hold about 7000 tons of freshwater. According to various embodiments, the tanks 330 may be interconnected via passageways, pumps, and valves that can actively control the relative amounts of water in each tank 330, for example to trim the weight distribution within the hull 20 and help to maintain a level orientation of the hull 20.

[0062] The secondary coolant loop 220 may comprise two discrete coolant loops 220a. As shown in FIG. 6, each discrete coolant loop 220a has its own steam generator 160, high pressure turbine 200, low pressure turbine(s) 210, condenser 250, and associated pumps 230, 260 and feedwater heaters 240. However, according to alternative embodiments, the coolant loop 220 may comprise a single coolant loop.

[0063] According to various embodiments, the auxiliary turbine 215 is a small (e.g., 5-20 MW) turbine that connects to the primary coolant loop 170 (see FIG. 6) to use steam from the hot primary coolant immediately after a reactor scam and later steam produced by the reactor’s decay heat. The auxiliary turbine 215 can be connected to an electrical generator and / or a water pump.

[0064] According to various embodiments, the power plant 100 may comprise greater or fewer steam generators 160, turbines 200, 210, 215, feedwater heaters 240, 260, pumps 240, and / or condensers 250. The low pressure turbines 210 may be omitted altogether.

[0065] As shown in FIG. 6, the secondary coolant loop 220 may branch out from multiple outlets 200b, 200c of the high pressure turbine 200. For example, one or more condensate outlets 200b from the turbine 200 (e.g., liquid / condensate outlets) may lead back to the steam generator 160 without passing through additional low pressure turbines 210. One or more steam outlets 200b may lead to mixing chambers or feedwater heaters 240 with condensate from the condenser 250 between the feedwater pumps 230, 260. One or more other steam outlets 200c from the turbine 200 may lead to inlets of the low pressure turbine(s) 210. Outlets of the low pressure turbines 210 in the secondary coolant loop 220 lead to the condenser 250 and then back to the steam generator 160.

[0066] As shown in FIGS. 2, 3, and 6, each steam generator 160 comprises a tube 160a and shell 160b steam generator 160. The primary coolant loop 170 passes through tubes 160a of the steam generator 160. The secondary coolant loop 220 passes between the shell 160b and the tubes 160a. The tubes 160a extend horizontally such that the steam generator 160 is a horizontal steam generator. As a result steam generated in the secondary coolant bubbles upwardly in a direction generally perpendicular to an axial direction of the horizontal tubes 160a. As a result, the horizontal steam generator 160 is a cross-flow heat exchanger (as opposed to a parallel flow or counterflow configuration common for vertical steam generators).

[0067] As shown in FIGS. 2 and 6, the output shafts 200a, 210a and input shaft 280a may be integrally formed and spin together. Alternatively the various shafts 200a, 210a, 280a may be separate from each other and operatively interconnected, either directly or through gearbox(es). One or more of the turbines 200, 210 may operatively connect to respective generators 280, rather than a single generator 280 as illustrated in FIGS. 2 and 6.

[0068] According to various embodiments, the primary coolant in the primary coolant loop 170 is borated distilled water. According to various embodiments, one or more pumps 310 (see FIG. 6) are disposed in the primary coolant loop 170 to pump primary coolant between the core 120 andsteam generators 160. The accumulator(s) 300 store additional primary coolant and are fluidly connected to the primary coolant loop 170 to provide additional primary coolant as needed.

[0069] The secondary coolant in the secondary coolant loop 220 may also be borated distilled water.

[0070] The core 120 may be removable to facilitate replacement with a fresh core 120 at the end of its cycle. The core 120 may comprise fuel bundles comprising fuel rods comprising fissile material (e g., uranium and / or plutonium) and / or fertile material (e.g., thorium). According to various embodiments, the fissile material comprises enriched uranium (e g., 1-20% U-235 enrichment).

[0071] As shown in FIG. 6, the condenser 250 includes a hot well 250a for collecting condensed secondary coolant. The tertiary coolant loop 270 comprises a seawater inlet 270a and seawater outlet 270b. One or more pumps may be disposed in the loop 270 to pump seawater through the loop 270.

[0072] Hereinafter, operation of the power plant 100 is described with reference to FIGS. 2, 3, and 6. The control rods / mechanism 130 are positioned to foster fission within the core 120, which heats the primary coolant flowing through the core 120 and primary coolant loop 170. The steam generators 160 transfer heat from the hot primary coolant to the secondary coolant, causing the secondary coolant to boil and form steam. This steam then drives the turbine 200. Condensates exit the turbine 200 through the outlets 200b and are pumped back to the steam generator using the pumps 230. Steam exits the turbine 200 via one or more steam outlets 200c and then drives the low pressure turbine(s) 210. Secondary coolant exits the low pressure turbine(s) 210 and flows through the condenser 250. The condenser 250 transfers heat from the secondary coolant into seawater, which condenses the secondary coolant. Condensing secondary coolant collects in the hot well 270, and is then pumped via the pumps 260, 230 back to the steam generator 160.

[0073] Ambient seawater enters from the body of water 30 into the inlet 270a of the tertiary coolant loop, absorbs heat from the secondary coolant in the condenser, and flows back out to the body of water via the outlet 270b. According to various embodiments, during operation of the power plant 100, the seawater exiting the outlet 270b is warmer than the ambient seawater entering the inlet 270a by no more than 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, and / or 20 °C. According to various embodiments, during operation of the power plant 100, heat dissipated into the body of water 30 by the power plant is (a) not more than 1100, 1000, 900, 800, 700, 600, 500, 400, and / or300 MWth, (b) at least 25, 50, 100, 200, 300, 400, 500, 600, 700, 800, and / or 900 MWth, and / or (c) between any two such upper and lower values (e.g., 25-1100 MWth, 600-1100 MWth). According to various embodiments, the temperature gradient of the expelled tertiary coolant quickly cools toward the ambient temperature of the body of water 30. According to various embodiments, the gradient shrinks to 2 °C less within 50 meters of where the tertiary coolant exits the outlet 270b.

[0074] The turbine(s) 200, 210 drive the generator(s) 280, which generates electricity. The electricity may pass through power conditioning equipment 290, and then on to the electric load 70 via the line 60. According to various embodiments, the generated electricity may transferred to the electric load 60 at any suitable voltage (e.g., at least 100, 150, 200, 250, 300, 350, and / or 400 V, less than 600, 550, 500, 450, 400, 350, 300, 250, 200, and / or 150 V, and / or at any voltage between any two such upper and lower limits (e.g., 100-600 V)) and current type (direct, alternating).

[0075] According to various embodiments the generated electricity can be transferred directly from the electrical generator 280 to an on-shore substation (e.g., part of the electric load 70) if the hull 20 is within 0.5 km of shore at 50 Hz or 60 Hz and a voltage 20 to 35 kV. If the hull 20 is further than 0.5 km off shore and in shallow water (e g., less than 50 m deep) the generated electricity could be transferred at 20 to 35 kV to transformers on a nearby platform above the body of water’s surface. The transformers would raise the voltage to 230 kV for transmission to the load 70. If the hull 20 is located in deeper water (e.g., 50 m to 200 m) the hull 20 could be built 20-40 m longer and the transformers could be located within the hull 20 and would transmit alternating current at 230-500 kV to on shore load 70. In a future embodiment, the 230-500 kV output of the internal generators 280 could be rectified to ±200 to 500 kV bipolar direct current for transmission 20-500 km undersea. In various embodiments, electricity is transferred over the line 70 as DC current, and an on shore inverter at or near the electric load 60 converts the generated electricity to AC current.

[0076] According to various embodiments, the power plant 100 may be sized to generate at least 25, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 600, 700, 800, and / or 900 MWe, less than 1100, 1000, 900, 800, 700, 600, 500, 400, 300, 200, and / or 100 MWe, and / or between any two such limits (e.g., 25-1100 MWe, 150-600 MWe, 400-800 MWe, 500-700 MWe, ~ 600MWe, ~ 300 MWe). According to various embodiments, the power plant 100 is configured to generate at least 25, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, and / or 2400 MWth, less than 2500,2400, 2300, 2200, 2100, 2000, 1900, 1800, 1700, 1600, 1500, 1400, 1300, 1200, 1100, 1000, 900, 800, 700, 600, 500, 400, 300, 200, and / or 100 MWth, and / or between any two such limits (e.g., 25- 2500 MWth, 450-2300 MWth, 1500-2500 MWth, 1800-220 MWth). According to various embodiments the power plant 100 may be sized to generate 150 to 600 MWe from reactor thermal outputs of 450 to 2300 MWth.

[0077] Seafloor Mount

[0078] As shown in FIGS. 1 and 3-5, the hull 20 is held in place at its location of operation 85 on the seafloor 40 via one or more baseplate(s) 390 and a plurality of struts 400. The baseplate(s) 390 may comprise concrete or other heavy structures and may be firmly mounted to the seafloor 40 via any suitable mechanisms (e.g., pins, concrete pilings, weight, etc.). Each strut 400 includes a first end 400a mounted to the hull 20 and a second, opposite end 400b mounted to a baseplate 390.

[0079] As shown in FIGS. 1 and 3, various struts 400 may extend from different locations on the hull 20 and at different angles so as to more securely control the position and orientation of the hull 20 when mounted at its location of operation 85. In the embodiment illustrated in FIG. 1, a group of three struts 400 extend from each of four spaced-apart anchor points 410 on the hull 20 down to the baseplate(s) 390. As a result, this embodiment employs 12 total struts 400. Within each group of three struts 400, each strut 400 extends from the anchor point 410 in a different direction (e.g., 120 degrees apart from each other as viewed from above) to spaced apart anchor points 420 on the baseplate(s) 390. As a result, the struts 400 of a group form a triangular pyramid so that a position of the anchor point 410 is controlled in all three translational directions by the struts 400.

[0080] According to various embodiments, the struts 400 form an angle relative to a vertical direction, of (a) at least 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 25, 30, 35, 40, and / or 45 degrees, (b) less than 50, 45, 40, 35, 30, 25, 20, 15, and / or 10 degrees, and / or (c) between any two such values (e.g., 3-50 degrees, 10-45 degrees, 5-30 degrees).

[0081] The combination of struts 400 and spaced apart anchor points 410 on the hull 20 ensures that the struts 400 limit movement of the hull 20 in all three translational directions and all three rotational directions. In the illustrated embodiment, the hull 20 includes four anchor points 410. However, according to alternative embodiments, three anchor points 410 could be used. Alternatively, additional anchor points 410 may be added to provide additional redundant support and / or to spread stresses more evenly around the hull 20.

[0082] According to various embodiments, a human-made depression may be formed in the seafloor 40 with the baseplate(s) 390 disposed within the depression. The depression may be made, for example, by dredging a depression into the seafloor 40. As a result, when the hull 20 is mounted to the seafloor 40 via the struts 400, the hull 20 is at least partially disposed within the depression, which can help to reduce the impact of waves and current on the hull 20.

[0083] According to various embodiments, the ends 400a, 400b and respective anchor points 410, 420 are configured to releasable lock together (e.g., via one or more bolts or pins, a remotely operated electric clamp etc ). The spherical connections between the struts 400 and anchor points 410, 420 preferably allow the struts to pivot in one more directions so that the struts 400 act only in tension and compression, without experiencing a bending stress. For example, as shown in FIGS. 4-5, the ends 400a, 400b may comprise a spherical connectors 430 mounted within spherical mounts defined at the ends 400a, 400b. Bolts, pins or other structures 440 (see FIG. 4) may extend through holes 430a (see FIG. 5) in the spherical connectors 430 and connect to respective anchor points 410, 420. The spherical connectors can rotate within the mounts at the ends 400a, 400b. Alternatively, the pivotal connections between the ends 400a, 400b of the struts 400 and respective anchor points 410, 420 may comprise any other type of suitable connection permitting pivoting in at least one direction (and preferably more directions), such as a gimbal similar to a CV joint of in an automobile drive shaft.

[0084] As shown in FIG. 5, the strut 400 comprises a double-acting gas-spring dampened pneumatic strut 400, which provides dampening in both tensile and compressive directions. The illustrated strut 400 comprises a piston rod 450 extending from the first end 400a to a double-acting piston 460. The piston 460 is mounted within a cylinder 470 that extends from the end 400b to an outer seal 480 through which the piston rod 450 extends. A neoprene boot 490 extends from the outer seal 480 and surrounds a portion of the piston rod 450. A distal end of the boot 490 attaches to the piston rod 450 and forms a seal that discourages water from the body of water 30 from getting into the cylinder 470, while allowing the piston rod 450 to move axially relative to the cylinder 470. An orificed damper ring 500 is mounted to the piston rod 450. An inner seal ring 510 is disposed within the cylinder 470 with the piston rod 450 passing through the inner seal ring 510.

[0085] A damper chamber 515 is formed within the cylinder 470 between the outer seal 480 and inner seal ring 510. The damper ring 500 includes a plurality of small axial holes / orifices connecting portions of the damper chamber 515 above and below the damper ring 500 to dissipatethe energy of seismic motion experienced by the strut 400. Movement of the piston rod 450 is dampened by restricted movement of gas through the orifices of the damper ring 500, which heats the gas. The heat is dissipated into the body of water 30.

[0086] An upper compressed gas chamber 520 is formed within the cylinder 470 between the inner seal 510 and an upper end of the piston 460 to provide a gas spring and dampened tensile extension of the strut 400. A lower compressed gas chamber is formed within the cylinder 470 below the piston 460 to provide a gas spring and dampened compression of the strut 400. A compressed gas reservoir 540 is disposed within the cylinder 470 and operatively connected to the chambers 520, 530 via one or more gas replenishing valves 550 so as to maintain an appropriate pressure within the chambers 520, 530 and control the neutral position of the piston 460. For example, a replenishment passageway (not shown) may connect the reservoir 540 to the upper chamber 520. The upper chamber 520 may also be replenished with pressurized gas via leakage around the piston 460. Leakage of gas past the inner seal 510 from the upper chamber 520 into the damper chamber 515 tends to replenish the damper chamber 515 with low pressure gas.Compressed gas inside the strut 400 is preferably an inert gas such as nitrogen. However, any other suitable gas may be used to provide pneumatic spring force and / or dampening.

[0087] While the illustrated strut 400 provides spring force and dampening via a doubleacting gas spring, the strut 400 may alternatively utilize any other type of suitable spring and / or dampening mechanism (e.g., springs, hydraulic dampeners, magnets).

[0088] The body of water 30 may be any type of body of water, e.g., fresh water, salt water, river, lake, sea, ocean, bay, etc. The body of water 30 is preferably a natural body of water, but may alternatively be a manmade body of water. As used herein, the term seafloor 40 refers to the ground underneath the body of water 30, regardless of whether the body of water 30 is a “sea.” Similarly, as used herein, the term “seawater” refers to the water of the body of water 30, regardless of whether the body of water 30 is a sea or is saltwater.

[0089] As shown in FIGS. 1 and 4, the struts 400 act in both compression and tension to maintain the hull 20 in its operational position above the seafloor 40.

[0090] According to various embodiments, the struts 400 have an end-to-end longitudinal length, as measured when the piston 460 is in a neutral position, of (a) at least 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 17, 19, and / or 20 meters, (b) less than 30, 25, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, and / or 5 meters, and / or (c) between any two such values (e.g., 3-30 meters,6-25 meters, 10-20 meters, 12-14 meters, ~ 13 meters). In the illustrated embodiment, each strut 400 has the same length and the struts are identical to each other. However, according to various alternative embodiments, different struts 400 can have different lengths.

[0091] While the illustrated embodiment utilizes struts 400 to mount the hull 20 to the seafloor 40, additional and / or alternative connectors may also be used to mount the hull 20 to the seafloor 40. For example, tensile-only connectors (e.g., chains, cables) may extend from the hull 20 to the seafloor 40 to tether the hull 20 to the seafloor 40. If the hull 20 is sufficiently buoyant, such tensile-only connectors may be sufficient to keep the hull mounted in its operational position. Tensile-only connectors may similarly extend upwardly from the hull 20 to buoyant structures (e.g., buoys) to help keep the hull 20 above the seafloor 40. If the hull 20

[0092] According to various embodiments, the struts 400 are tuned and configured to dampen a transfer of seismic movement from the seafloor 40 to the hull 20 in both tensile and compressive directions. For example, such tuning / configuration to provide seismic dampening may involve one or more of sizing the cross-sectional area of the chambers 520, 530; selecting the pressure in the chambers 520, 530; sizing orifices / leakage paths between the chambers 520, 530; selecting appropriate compressive and tensile stroke lengths for the struts 400; utilizing an appropriate number of struts 400; orienting the struts 400 appropriately, etc.

[0093] According to various embodiments, the struts 400 are sized and positioned to support the hull 20 such that the hull 20 remains spaced from the seafloor 40. This space allows for some water flow between the hull 20 and seafloor 40, and may help to avoid the direct transfer of seismic vibrations from the seafloor 40 to the hull 20. This seawater-fdled space between the hull 20 and the seafloor 40 may also help to insulate the hull 20 from seismic activity in the seafloor 40. According to various embodiments, the hull 20 is supported above the seafloor 40 (including any human-made depression on the seafloor 40) such that the entire hull 20 is mounted (a) at least 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13, 14, and / or 15 meters away from the seafloor 40, (b) within 20, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, and / or 1 meter of the seafloor 40, and / or (c) between any two such values (e.g., 0.5-20 meters from the seafloor 40, 5-15 meters from the seafloor 40, 7-11 meters from the seafloor 40, 3-10 meters from the seafloor 40, about 9 meters from the seafloor 40).

[0094] According to various embodiments, the hull 20 is mounted to an area of the seafloor 40 (including any human-made depression on the seafloor 40) that is (a) at least 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, and / or 150 meters deep, (b) less than 200, 150, 140, 130, 120,110, 100, 90, 80, 70, 60, 50, 40, and / or 30 meters deep, and / or (c) between any two such values (e.g., between 20 and 200 meters deep, between 30 and 200 meters deep, between 50 and 150 meters deep, ~ 100 meters deep). Similarly, according to various embodiments, the hull 20 is mounted to the seafloor 40 such that an uppermost portion of the hull 20 and / or a lowermost portion of the hull 20 is (a) at least 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, and / or 150 meters deep, (b) less than 200, 150, 140, 130, 120, 110, 100, 90, 80, 70, 60, 50, 40, and / or 30 meters deep, and / or (c) between any two such values (e g., between 20 and 200 meters deep, between 50 and 150 meters deep, - 100 meters deep). According to various embodiments, the depth is selected to avoid higher currents that are typical closer to the surface of the body of water 30. Positioning the hull 20 relatively deep in the water may beneficially reduce the impact of a tsunami (25 meter height, 100 km wavelength) or hurricane (e.g., generating -30 m high waves, in accordance with the JONSWAP wave spectrum for a 100-year hurricane.) on the submerged hull 20.

[0095] According to various embodiments, the hull 20’ s location of operation 85 on the seafloor 40 is (a) at least 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.25, 1.5, 1.75, 2, 3, 4, 5, 6, 7, 8, 9, and / or 10 km offshore, (b) not more than 100, 90, 80, 70, 60, 50, 40, 30, 20, 15, 10, 5, 4, 3, 2, 1, and / or 0.5 km offshore, and / or (c) between any two such values (e.g., 0.3-100 km offshore, 0.3-80 km offshore). According to various embodiments, the location of operation 85 is selected so as to be reasonably close to the electric load 70, to provide the desired water depth, and to be appropriately spaced from the electric load 70, people living and working on shore, and / or shipping or boat channels.

[0096] Physical Protection

[0097] Additional structures may be provided to further protect the hull 20 and power plant 100, for example from external risks. For example, as shown in FIG. 3, a shield 600 may be mounted above the hull 20 to protect the hull 20 from various threats (e.g., anchors, sabotage devices). According to various embodiments, the shield 600 may comprise grating (e.g., with 100 mm openings), nets, frozen seawater (e.g., formed inside a chamber of the shield 600 using refrigeration equipment). The shield 600 is designed to absorb the impact of a submarine or surface merchant vessel.

[0098] For example, according to various embodiments, the shield 600 comprises a chamber having frozen seawater therein, and refrigeration equipment to cool the seawater within the shield 600. The frozen seawater may have a dendric consistency due to salt concentration variation duringthe freezing process. The shield container 600 may comprise a steel shell with an inner closed-cell extruded polystyrene foam (XPS) insulation to thermally insulate the frozen seawater from the surrounding body of water 30.

[0099] A quarantine zone may be established around the hull 20, e.g., using netting and / or warning buoys, to prevent unauthorized entities from getting within a certain distance from the hull 20.

[0100] Control Center

[0101] According to various embodiments, when the power station 10 is operational, the hull 20 is unmanned. According to various embodiments, the hull 20 includes no crew quarters, and includes no life support systems. According to various embodiments, an oxygen concentration within the gas filled portions of the hull 20 is too low for humans. As shown in FIG. 1, a control center (or room(s)) 700 of the power station 10 is located a distance from the hull 20. According to various embodiments, the control center 700 may be located on shore (as shown in FIG. 1), on a floating vessel (e.g., ship, barge, etc.), or above a surface of the body of water on a support structure mounted to the seafloor (e.g., like an oil platform). The control center 700 includes controls and instruments to facilitate human monitoring and control of the power station 10. The control center 700 is preferably operatively connected to the power station 10 components in the hull 20 via a hardwired connection and communications wires 710, as shown in FIG. 1. A wireless backup communications link between the hull 20 and control center 700 may additionally and / or alternatively be used (e.g., via an antenna mounted to a buoy at the surface of the water above the hull 20 with wires connecting the antenna to the hull 20 and a wireless link (e.g., direct radio link, satellite link, etc.) to the control center 710.

[0102] Electric Load 70

[0103] As shown in FIG. 1, the power station 10 provides electric power to an on-shore electric load 70 to provide electricity to the on-shore electric load 70 via the output electric line 60. According to various embodiments, the on shore electric load 70 may be a terrestrial electric grid.

[0104] Maintenance Facility

[0105] As shown in FIG. 7, the power plant 100 and hull 20 may be manufactured, repaired, refueled, and decommissioned at an onshore facility 1000.

[0106] The facility 1000 may be located on land 1005 adjacent to the body of water 30 to facilitate transportation of the hull 200 and power plant 100 between the maintenance facility 1000and the body of water 30 (and ultimately the location of operation 85 on the seafloor 40, as shown in FIG. 1). The facility 1000 is preferably located within a protected portion of the body of water 30 (e.g., a manmade or natural harbor or bay).

[0107] As shown in FIG. 7, the facility 1000 includes a reactor 110 module assembly station 1010, a turbine / generator assembly station 1020, an instrumentation and control (I&C) assembly station 1030, a small components fabrication area 1040, a storage area 1050, final assembly bays 1060, air-bearing cradles 1070 configured to support and transport the hull 20 and power plant 100 within the facility 1000, transfer locks 1080, receiving docks 1090, refueling bays 1100, spent fuel handling facilities 1110, and a breakwater 1120. According to various embodiments, the entire onshore portion of the facility 1000 may be housed within one or more buildings. The hull 20 and power plant 100 may be manufactured and / or assembled on shore at the facility 1000.

[0108] The air-bearing cradles 1070 are configured to support the hull 20 and all components built and installed within the hull 20 during manufacture. According to various embodiments, the air-bearing cradles 1070 float on large concrete slabs covering the pertinent areas of the ground level 1005a of the facility 1000. According to various embodiments, the ground level 1005a of the facility is sufficiently high above sea level 30a to minimize a risk of flooding.According to various embodiments, the ground level 1005a is at least 10, 15, and / or 20 feet (e.g., ~ 18 feet) above sea level 30a of the body of water 30.

[0109] According to various embodiments, each cradle 1070 is configured to support and transfer the full weight of the hull 20 and all power plant 100 components disposed therein. For example, the cradle 1070 may be designed to support and transfer at least 20000, 25000, 30000, 35000, 40000, 45000, and / or 50000 tons so that the cradle 1070 can support the weight of the hull 20. According to various embodiments, the cradle can lift this amount of weight using an air compressor with 500-1000 kWe power, and an air pressure under the cradle 1070 of about 100 to 250 kPa. The air-bearing cradles 1070 facilitate transfer of the hull 20 and power plant 1000 around the facility 1000 and to and from the transfer locks 1080.

[0110] As shown in FIGS. 8-11, the onshore portions of the facility 1000 are at a ground level 1005a that is above a water level 30a of the body of water. The transfer locks 1080 are used to raise and lower hulls 20 between the facility 1000 ground level and the water level within the body of water 30. FIGS. 8-10 illustrate the progressive use of the lock 1080 to raise the hull 20 from within the body of water 30 to the air-bearing cradle 1070 (FIGS. 8-10). As shown in FIG. 8, thehull 20 is moved within the water into the lock 1080. A water-side door 1080a and shore-side door 1080b of the lock 1080 are then shut and the lock 1080 fdled with water to a water level 1150 shown in FIG. 9. The hull 20 is then moved within the water to a position on the cradle 1070. The water level in the lock 1080 is then dropped back down to sea level 30a, which leaves the hull 20 supported on the cradle 1070. As shown in FIG. 10, the shore-side door 1080b is then opened and the air-bearing cradle 1070 and hull 20 supported thereon can be moved to other areas of the facility 1000. The reverse procedure is used to lower the hull 20 from the ground level 1005a to the water.

[0111] As shown in FIG. 7, once a hull 20 and power plant 100 are lowered into the body of water 30, they may be loaded onto or into a transport ship 1200 for transport to the location of operation 85. Alternatively, the hull 20 and power plant 100 may be tethered externally to a transport ship 1200 for transport to the location of operation 85. According to various embodiments, the ballast tanks 80 and / or tanks 330 may be emptied so that the hull 20 floats as high as possible on the water, making it easier to transport on the water body 30 and handle at the facility 1000, e.g., with about 12 meters of draft. According to various embodiments, an amount of water in the ambient water ballast tanks 80 and fresh water tanks 330 is controlled (e.g., via pumps, valves, etc.) so that the hull 20 is neutrally buoyant or positively buoyant during transportation between the facility 1000 and the location of operation 85 (see FIG. 1) (e.g., providing a 12 meter draft), and slightly negatively buoyant when in use. According to various embodiments, fresh water from tank(s) on a nearby support ship may be transferred into the tanks 330 to fill the tanks 330 and reduce the hull’s buoyancy. Conversely, fresh water from the tanks 330 may be transferred to tank(s) on the support ship to drain the tanks 330 and increase the hull’s buoyancy. Ambient water can be transferred between the ballast tanks 80 and body of water 30 to fill and empty the ballast tanks 80.

[0112] According to various embodiments, the breakwater 1120 may comprise floatable tidal barrages. Alternatively, the breakwater 1120 may comprise rocks, concrete, or other heavy structures to protect the portion of the body of water 30 behind the breakwater 1120.

[0113] According to various embodiments, the transportation of the hull 20 on or in the body of water 30 requires significant draft. According to various embodiments, a depth of the body of water 30 leading into the protected area behind the breakwater 1120 and up to the locks 1080 and refueling bays 1110 is at least 12, 20, 25, 30, 35, 40, 45, and / or 50 meters deep. Channels leading tothe locks 1080 and refueling bays 1110 (or other areas of the facility 1000) may be dredged in the body of water 30 to create this depth.

[0114] Transportation Of Hull 20

[0115] According to various embodiment, the hull 20 and power plant 100 are assembled at the facility 1000, lowered into the body of water 30, and transported to the location of operation 85 using the transport ship 1200 (e.g., by transporting the hull 20 while within or on the ship 1200). According to various embodiments, the location of operation 85 is spaced from the facility 1000 by (a) at least 10, 50, 100, 150, 200, 250, 500, 750, 1000, 1500, 2000, 2500, 3000, 4000, and / or 5000 km, (b) no more than 6000, 5000, 4000, 3000, 2500, 2000, 1500, 1000, 750, 500, 250, 200, 150, 100, and / or 50 km, and / or (c) between any two such distances (e.g., 10-6000 km).

[0116] Once at the water surface above the location of operation 85, the ballast tanks 80 are filled with water such that the hull 20 is neutrally buoyant or slightly negatively buoyant. A ship 1200 mounted crane, winch, or other equipment may be used to guide the hull 20 from its location at or near the water’s surface to its location of operation 85 at the sea floor 40. Manned or unmanned submersible vehicles may be used to help appropriately position the hull 20 above the seafloor 40.

[0117] According to various embodiments, the struts 400 may be first attached to the hull 20 (e.g., at the water’s surface) and then the struts can be attached to the seafloor 40. Alternatively, the struts 400 may be first mounted to the seafloor 40 and then mounted to the hull 20. Either way, at least one connection between one end 400a, 400b of the struts 400 and an anchor point 410, 420 on either the hull 20 or the seafloor 40 will be made at depth. According to various embodiments, a submersible vehicle (manned or unmanned) may help to appropriately locate each strut 400. The bolt 440 can then be inserted into the end 400a, 400b (or a ball joint at the end 400a, 400b) and threaded into the anchor point 410, 420. Alternatively, the connection between the struts 400 and anchor points 410 and / or 420 may rely on an automated locking system, which may be remotely controlled.

[0118] The electric line 60 and communications line 710 may be operatively connected to the hull 20 before or after the hull 20 is mounted to the seafloor 40. According to various embodiments, the electric line 60 is a subsea electric line that lays on the seafloor 40.

[0119] The power plant 100 then goes through a start-up procedure, resulting in the power plant 100 generating electricity and providing electric power to the electric load 70 via the electric line 60.

[0120] According to various embodiments, the power station 10’s core 120 is configured to provide a refueling fuel cycle of (a) at least 20, 24, 30, 36, 42, 48, 54, and / or 60 months, (b) less than 72, 66, 60, 54, 48, 42, and / or 36 months, and / or (c) between any two such values (e.g., 20-72 month fuel cycle, 20-60 month fuel cycle, ~ 60 month fuel cycle). At the completion of each cycle, the hull 20 is transported from its location of operation 85 (shown in FIG. 1) to the maintenance facility 1000 in an order that is generally the reverse of the order in which the hull 20 is deployed from the facility 1000 to the seafloor 40. The hull 20 may be delivered to the refueling bay 110, where the spent fuel core 120 is removed and replaced with a fresh fuel core 120 to refuel the power plant 100. The spent fuel is then stored, at least temporarily, at the facility 1000. As a result, spent fuel is not stored in the hull 20.

[0121] The hull 20 and refueled power plant 100 can then be transported back to the location of operation 85 (or a second, different location of operation) in the same manner as described above and mounted to the seafloor 40. The power plant 100 can then proceed through a start-up procedure for the second (or subsequent) fuel cycle.

[0122] According to various embodiments, the power plant 100 is designed for a three fuel cycle life. At the completion of the third (or last fuel cycle), the hull 20 is transported to the facility 1000 in the same manner as described above for refueling. At the facility 1000, the power plant 100 is decommissioned.

[0123] Although the present patent application has been described in detail for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that the present patent application is not limited to the disclosed embodiments, but, on the contrary, is intended to cover modifications and equivalent arrangements that are within the spirit and scope of the appended claims. In addition, it is to be understood that the present patent application contemplates that, to the extent possible, one or more features of any embodiment can be combined with one or more features of any other embodiment. Nothing in this section, the Summary, the title, or the abstract is intended to limit the scope of any invention disclosed herein.

Claims

What is claimed is:

1. A power station comprising: a submersible hull defining an interior; a nuclear power plant comprising a nuclear reactor disposed in the interior; an output electric line extending from the power plant and configured to transfer electricity generated by the power plant to an electric load outside the hull; and at least one connector configured to mount the hull to a seafloor of a body of water such that the hull is submerged within the body of water.

2. The power station of claim 1, wherein the hull, including all material in the interior, is negatively buoyant, and wherein the interior is watertight.

3. The power station of claim 1, wherein the hull is submerged within the body of water.

4. The power station of claim 1, wherein: the hull has an effective density DH, the water in the body of water has a density DW, and(1.OOlxDW) < DH < (1.05xDW).

5. The power station of claim 1, wherein the at least one connector comprises at least one strut configured to operate in both tension and compression.

6. The power station of claim 5, wherein the at least one strut comprises at least one dampener configured to dampen a transfer of seismic movement from the seafloor to the hull in both tensile and compressive directions.

7. The power station of claim 5, wherein the at least one strut is shaped and configured to support the hull such that the hull remains spaced from the seafloor.

8. The power station of claim 5, wherein the at least one strut comprises a plurality of struts each having a first end mounted to the hull and a second end mounted to the seafloor.

9. The power station of claim 8, further comprising at least one base plate mounted to the seafloor, wherein the second ends of the struts mount to the seafloor via the at least one base plate.

10. The power station of claim 1, wherein: the hull defines a pressure boundary separating the power plant from an ambient environment outside the hull; andthe pressure boundary prevents water from crossing the pressure boundary.

11. The power station of claim 1, wherein the interior is configured to contain fresh water to act as a shielding material and heat sink for the power plant.

12. The power station of claim 1, wherein the interior is configured to contain an inert gas with a low enough oxygen concentration to act as a fire suppressant.

13. The power station of claim 1, further comprising a control center outside the hull and operatively connected to the power plant to facilitate human monitoring and control of the power plant from outside the hull.

14. The power station of claim 13, wherein the control center operatively connects to the power plant via a hardwired connection and a back-up wireless connection.

15. The power station of claim 13, wherein the control center is on shore, on a floating vessel, or above a surface of the body of water on a support structure mounted to the seafloor.

16. The power station of claim 1, wherein: the electric load comprises an onshore electric load, and the output electric line is configured to extend from the power plant to the onshore electric load to provide electricity to the onshore electric load.

17. The power station of claim 1, wherein the power plant comprises: a reactor vessel having a core comprising fissile material; a steam generator; a primary coolant loop extending between the reactor and the steam generator; at least one turbine having an output shaft; a secondary coolant loop extending between the steam generator and the at least one turbine; and an electric generator having an input shaft operatively connected to the output shaft, wherein the reactor is configured to heat a primary coolant flowing through the primary coolant loop, wherein the steam generator is configured to transfer heat from the primary coolant to secondary coolant in the secondary coolant loop, thereby causing the secondary coolant to form steam, wherein the secondary coolant loop is configured to circulate steam through the at least one turbine, thereby spinning the turbine, output shaft, and input shaft to generate electricity.

18. The power station of claim 17, wherein: the steam generator comprises a tube and shell steam generator in which the primary coolant loop passes through tubes of the steam generator; the secondary coolant loop passes between the shell and the tubes; and the tubes extends horizontally such that the steam generator is a horizontal steam generator.

19. The power station of claim 17, further comprising: a condenser, wherein at least a portion of the secondary coolant loop extends through the condenser; and a tertiary coolant loop extending between an ambient environment outside the hull and the condenser, wherein the condenser is configured such that at least a portion of the secondary coolant exiting the at least one turbine circulates through the condenser, which transfers heat from the secondary coolant into water in the tertiary coolant loop and then into the body of water.

20. A method of using the power station of claim 1, the method comprising: transporting the hull to an offshore site; mounting the hull to the seafloor via the at least one connector such that the hull is submerged at an offshore location of operation; generating electricity using the power plant; and transferring electricity generated by the power plant to the electric load via the output electric line.

21. The method of claim 20, wherein the electric load is located on shore, and the hull is disposed offshore during said generating and transferring.

22. The method of claim 20, wherein said mounting comprises mounting the hull at least partially within a human-made depression in the seafloor.

23. The method of claim 20, wherein said mounting results in the entire power plant and hull being at least 25 meters under a surface of the body of water.

24. The method of claim 20, further comprising, after said generating and transferring: unmounting the hull from the seafloor; transporting the hull to an onshore refueling facility; at the refueling facility, removing spent fissile fuel from the reactor, and replacing the spent fuel with fresh fissile fuel;transporting the hull to the offshore location of operation for the power plant or a second offshore location of operation for the power plant; mounting the hull to the seafloor at the offshore location of operation such that the hull is disposed below the surface of the body of water; generating electricity using the power plant; and transferring electricity generated by the power plant to the electric load or a second electric load via the output electric line.

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