US-20260128185-A1 - MICRO INTEGRAL NUCLEAR REACTOR

US20260128185A1US 20260128185 A1US20260128185 A1US 20260128185A1US-20260128185-A1

Abstract

A micro integral nuclear reactor and nuclear power system including the micro integral nuclear reactor. The micro integral nuclear reactor can include a reactor core, a steam generator, primary coolant circuit, and a reactor pressure vessel. The reactor pressure vessel can houses the reactor core, the steam generator, and the primary coolant circuit. The fuel of the reactor core can be enriched to a concentration of 5 percent or greater and less than 20 percent U-235 by weight of uranium within the reactor core. When operating, the micro integral nuclear reactor can produce a thermal power output from 6 megawatts-thermal (MWt) to 60 MWt. The nuclear power system can in lude a turbine-generator assembly fluidly coupled to the steam generator and, when operating, the nuclear power system produces an electrical power output from 2 megawatts-electric (MWe) to 20 MWe.

Inventors

Samuel Gibson
Christopher R. Neal
Ross Ridenoure
Andrew M. Ward

Assignees

Hadron Energy, Inc.

Dates

Publication Date: 20260507
Application Date: 20251031

Claims (20)

1 . A micro integral nuclear reactor comprising: a reactor core including a plurality of fuel assemblies, each fuel assembly comprising a plurality of fuel elements, the plurality of fuel assemblies defining core primary coolant flow passages through the reactor core, the reactor core being structured such that, when operating, a primary coolant flows through the core primary coolant flow passages and absorbs heat generated by nuclear fission within the reactor core, each fuel element containing uranium-235 (U-235), and the fuel of the reactor core being enriched to a concentration of 5 percent or greater and less than 20 percent U-235 by weight of uranium within the reactor core; a steam generator fluidly connected to the core primary coolant flow passages to receive the primary coolant and, when operating, transfer heat from the primary coolant to a secondary coolant to generate steam; a primary coolant circuit fluidly coupling the core primary coolant flow passages and the steam generator such that, when operating, the primary coolant circulates between the reactor core and the steam generator; and a reactor pressure vessel housing the reactor core, the steam generator, and the primary coolant circuit; wherein, when operating, the micro integral nuclear reactor produces a thermal power output from 6 megawatts-thermal (MWt) to 60 MWt.
2 . The micro integral nuclear reactor of claim 1 , wherein the fuel of the reactor core is enriched to a concentration of 5 percent to 10 percent or less U-235 by weight of uranium within the reactor core.
3 . The micro integral nuclear reactor of claim 1 , wherein the primary coolant is light water.
4 . The micro integral nuclear reactor of claim 1 , further comprising a pressurizer located within the reactor pressure vessel and fluidly connected to the primary coolant circuit and configured to regulate the pressure of the primary coolant at an operating pressure sufficient to maintain the primary coolant in a liquid state during operation.
5 . The micro integral nuclear reactor of claim 1 , wherein the steam generator is a once-through steam generator in which the primary coolant flows during operation through the steam generator in a single pass between an inlet and an outlet of the steam generator.
6 . The micro integral nuclear reactor of claim 5 , wherein the steam generator includes a straight-tube heat-exchange assembly through which the primary coolant flows during operation.
7 . The micro integral nuclear reactor of claim 1 , further comprising one or more neutron reflectors surrounding the reactor core, the one or more neutron reflectors being circumferentially disposed around the reactor core.
8 . The micro integral nuclear reactor of claim 7 , wherein the primary coolant circuit is a primary coolant loop with a portion of the primary coolant loop circumferentially disposed around the reactor core.
9 . The micro integral nuclear reactor of claim 1 , wherein the reactor pressure vessel comprises a cylindrical central section and hemispherical end caps at opposing axial ends of the cylindrical central section.
10 . The micro integral nuclear reactor of claim 9 , wherein the cylindrical central section of the reactor pressure vessel includes one or more circumferential flanges or coupling bands joining a plurality of vessel segments to form the reactor pressure vessel.
11 . The micro integral nuclear reactor of claim 1 , wherein a height of the reactor pressure vessel is greater than a diameter of the reactor pressure vessel.
12 . The micro integral nuclear reactor of claim 1 , wherein a diameter of the reactor pressure vessel is from 1 m to 5 m.
13 . The micro integral nuclear reactor of claim 1 , wherein a diameter of the reactor pressure vessel is from 1 m to 3 m.
14 . The micro integral nuclear reactor of claim 1 , wherein the primary coolant circuit is a primary coolant loop and the micro integral nuclear reactor further comprises a primary-coolant pump disposed within the reactor pressure vessel and coupled to the primary-coolant loop to circulate the primary coolant through the core primary coolant flow passages and the steam generator during operation.
15 . A nuclear power system comprising: a micro integral nuclear reactor including: a reactor core including a plurality of fuel assemblies, each fuel assembly comprising a plurality of fuel elements, the plurality of fuel assemblies defining core primary coolant flow passages through the reactor core, the reactor core being structured such that, when operating, a primary coolant flows through the core primary coolant flow passages and absorbs heat generated by nuclear fission within the reactor core, each fuel element containing uranium-235 (U-235), and the fuel of the reactor core being enriched to a concentration of 5 percent or greater and less than 20 percent U-235 by weight of uranium within the reactor core; a steam generator fluidly connected to the core primary coolant flow passages to receive the primary coolant and, when operating, transfer heat from the primary coolant to a secondary coolant to generate steam; a primary coolant circuit fluidly coupling the core primary coolant flow passages and the steam generator such that, when operating, the primary coolant circulates between the reactor core and the steam generator; and a reactor pressure vessel housing the reactor core, the steam generator, and the primary coolant circuit; a turbine-generator assembly fluidly coupled to the steam generator to receive the steam and, when operating, generate electrical power and discharge exhaust; a condenser fluidly coupled to the turbine-generator assembly to condense the exhaust into condensed secondary coolant; and a secondary-coolant circuit fluidly coupling the steam generator, the turbine-generator assembly, and the condenser such that, when operating, the condensed secondary coolant is returned from the condenser to the steam generator to complete a recirculating flow path, wherein, when operating, the nuclear power system produces an electrical power output from 2 megawatts-electric (MWe) to 20 MWe.
16 . A micro integral nuclear reactor comprising: a reactor core including a plurality of fuel assemblies, each fuel assembly comprising a plurality of fuel elements, the plurality of fuel assemblies defining core primary coolant flow passages through the reactor core, the reactor core being structured such that, when operating, a primary coolant flows through the core primary coolant flow passages and absorbs heat generated by nuclear fission within the reactor core, each fuel element containing uranium-235 (U-235), and the fuel of the reactor core being enriched to a concentration of 5 percent or greater and less than 20 percent U-235 by weight of uranium within the reactor core; one or more neutron reflectors surrounding the reactor core, the one or more neutron reflectors being circumferentially disposed around the reactor core; a steam generator fluidly connected to the core primary coolant flow passages to receive the primary coolant and, when operating, transfer heat from the primary coolant to a secondary coolant to generate steam; a primary coolant loop fluidly coupling the core primary coolant flow passages and the steam generator such that, when operating, the primary coolant circulates between the reactor core and the steam generator, wherein the primary coolant is light water; a pressurizer fluidly connected to the primary coolant loop and configured to regulate the pressure of the primary coolant at an operating pressure sufficient to maintain the primary coolant in a liquid state during operation; and a reactor pressure vessel housing the reactor core, the steam generator, the primary coolant loop, and the pressurizer, wherein, when operating, the micro integral nuclear reactor produces a thermal power output from 6 megawatts-thermal (MWt) to 60 MWt.
17 . A nuclear power system comprising: the micro integral nuclear reactor of claim 16 ; a turbine-generator assembly fluidly coupled to the steam generator to receive the steam and, when operating, generate electrical power and discharge exhaust; a condenser fluidly coupled to the turbine-generator assembly to condense the exhaust into condensed secondary coolant; and a secondary-coolant circuit fluidly coupling the steam generator, the turbine-generator assembly, and the condenser such that, when operating, the condensed secondary coolant is returned from the condenser to the steam generator to complete a recirculating flow path, wherein, when operating, the micro power system produces an electrical power output from 2 megawatts-electric (MWe) to 20 MWe.
18 . The micro integral nuclear reactor of claim 16 , wherein a diameter of the reactor pressure vessel is from 1 m to 5 m.
19 . The micro integral nuclear reactor of claim 16 , wherein the reactor pressure vessel comprises a cylindrical central section and hemispherical end caps at opposing axial ends of the cylindrical central section.
20 . The micro integral nuclear reactor of claim 19 , wherein the cylindrical central section of the reactor pressure vessel includes one or more circumferential flanges or coupling bands joining a plurality of vessel segments to form the reactor pressure vessel.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application No. 63/715,445 , filed Nov. 1, 2024, and titled “MICRO MODULAR REACTORS AND USES THEREOF,” the entirety of which is incorporated herein by reference. TECHNICAL FIELD The present disclosure relates to nuclear reactors for power generation, particularly nuclear reactors for electrical power generation. BACKGROUND Nuclear reactors for power generation rely on controlled fission reactions within a reactor core to produce thermal energy. The thermal energy is typically transferred to a working fluid through a primary coolant loop. The working fluid can be used to generate steam that drives a turbine coupled to an electrical generator. SUMMARY The subject matter described herein generally relates to compact, integral, nuclear reactors and to nuclear power systems that use such integral reactors. The nuclear power systems and nuclear reactors can be configured to generate thermal energy and electrical power through controlled nuclear fission. The nuclear reactor can be a pressurized-water reactor. In one aspect, the subject matter described herein relates to a micro integral nuclear reactor including a reactor core, a steam generator, primary coolant circuit, and a reactor pressure vessel. The reactor core includes a plurality of fuel assemblies. Each fuel assembly comprises a plurality of fuel elements. The plurality of fuel assemblies define core primary coolant flow passages through the reactor core. The reactor core is structured such that, when operating, a primary coolant flows through the core primary coolant flow passages and absorbs heat generated by nuclear fission within the reactor core. Each fuel element containing uranium-235 (U-235), and the fuel of the reactor core is enriched to a concentration of 5 percent or greater and less than 20 percent U-235 by weight of uranium within the reactor core. The steam generator is fluidly connected to the core primary coolant flow passages to receive the primary coolant and, when operating, transfer heat from the primary coolant to a secondary coolant to generate steam. The primary coolant circuit fluidly couples the core primary coolant flow passages and the steam generator such that, when operating, the primary coolant circulates between the reactor core and the steam generator. The reactor pressure vessel houses the reactor core, the steam generator, and the primary coolant circuit. When operating, the micro integral nuclear reactor produces a thermal power output from 6 megawatts-thermal (MWt) to 60 MWt. In another aspect, the subject matter described herein relates to a nuclear power system including a micro integral nuclear reactor, a turbine-generator assembly, a condenser, and a secondary-coolant circuit. The micro integral nuclear reactor includes a reactor core, a steam generator, primary coolant circuit, and a reactor pressure vessel. The reactor core includes a plurality of fuel assemblies. Each fuel assembly comprises a plurality of fuel elements. The plurality of fuel assemblies define core primary coolant flow passages through the reactor core. The reactor core is structured such that, when operating, a primary coolant flows through the core primary coolant flow passages and absorbs heat generated by nuclear fission within the reactor core. Each fuel element containing uranium-235 (U-235), and the fuel of the reactor core is enriched to a concentration of 5 percent or greater and less than 20 percent U-235 by weight of uranium within the reactor core. The steam generator is fluidly connected to the core primary coolant flow passages to receive the primary coolant and, when operating, transfer heat from the primary coolant to a secondary coolant to generate steam. The primary coolant circuit fluidly couples the core primary coolant flow passages and the steam generator such that, when operating, the primary coolant circulates between the reactor core and the steam generator. The reactor pressure vessel houses the reactor core, the steam generator, and the primary coolant circuit. The turbine-generator assembly is fluidly coupled to the steam generator to receive the steam and, when operating, generate electrical power and discharge exhaust. The condenser is fluidly coupled to the turbine-generator assembly to condense the exhaust into condensed secondary coolant. The secondary-coolant circuit is fluidly coupling the steam generator, the turbine-generator assembly, and the condenser such that, when operating, the condensed secondary coolant is returned from the condenser to the steam generator to complete a recirculating flow path. When operating, the nuclear power system produces an electrical power output from 2 megawatts-electric (MWe) to 20 MWe. In a further aspect, the subject matter described herein relates to a micro integral nuclear reactor including a reactor core, one or more neutron reflectors surroun