Controlling a power output of a nuclear reaction without control rods

Patent metadata

Field	Value
Publication number	US-11380448-B2
Application number	US-201816237059-A
Country	US
Kind code	B2
Filing date	Dec 31, 2018
Priority date	Dec 29, 2017
Publication date	Jul 5, 2022
Grant date	Jul 5, 2022

Abstract

A nuclear power system includes a reactor vessel that includes a reactor core mounted therein. The reactor core includes nuclear fuel assemblies configured to generate a nuclear fission reaction. The reaction vessel does not include any control rod assemblies therein. The nuclear power system further includes a riser positioned above the reactor core, a primary coolant flow path, a primary coolant that circulates through the primary coolant flow path to receive heat from the nuclear fission reaction and release the received heat to generate electric power in a power generation, and a control system communicably coupled to the power generation system and configured to control a power output of the nuclear fission reaction independent of any control rod assemblies.

First claim

What is claimed is:

1. A nuclear power system, comprising:
a reactor vessel that comprises a reactor core mounted within a volume of the reactor vessel, wherein the reactor core comprises one or more nuclear fuel assemblies configured to generate a nuclear fission reaction, and wherein the reactor vessel does not include any control rod assemblies therein;
a riser positioned above the reactor core;
a primary coolant flow path that extends from a bottom portion of the volume below the reactor core, through the reactor core, within the riser, and through an annulus between the riser and the reactor vessel back to the bottom portion of the volume;
a primary coolant that circulates through the primary coolant flow path to receive heat from the nuclear fission reaction and release the received heat to generate electric power in a power generation system coupled to the primary coolant flow path;
a chemical injection system in fluid communication with the primary coolant flow path; and
a control system communicably coupled to the power generation system and the chemical injection system, wherein the control system is configured to control a power output of the nuclear fission reaction independent of any control rod assemblies by controlling one or more parameters of at least one of the power generation system or the chemical injection system, and wherein the control system is configured to perform operations to control one or more parameters of the chemical injection system, the operations comprising:
determining that the power output of the nuclear fission reaction is greater than an upper value or less than a lower value;
based on the determination, adjusting an amount of a chemical injected into the reactor core from the chemical injection system to adjust the power output of the nuclear fission reaction; and
subsequent to the adjustment, determining that the power output is within a range.

2. The nuclear power system of claim 1 , wherein the control system is further configured to perform operations to control one or more parameters of the power generation system comprising:
based on the determination, controlling the power generation system to adjust at least one of a turbine inlet steam valve or a feed water pump to adjust the power output of the nuclear fission reaction.

3. The nuclear power system of claim 2 , wherein the operation of controlling the power generation system to adjust the turbine inlet steam valve comprises at least one of:
adjusting the turbine inlet steam valve toward a fully closed position to decrease the power output of the nuclear fission reaction; or
adjusting the turbine inlet steam valve toward a fully open position to increase the power output of the nuclear fission reaction.

4. The nuclear power system of claim 2 , wherein the operation of controlling the power generation system to adjust the feed water pump comprises at least one of:
decreasing an output flowrate of the feed water pump to decrease the power output of the nuclear fission reaction; or
increasing the output flowrate of the feed water pump to increase the power output of the nuclear fission reaction.

5. The nuclear power system of claim 1 , further comprising:
a containment vessel sized to enclose the reactor vessel such that an open volume is defined between the containment vessel and the reactor vessel; and
a boron injection system positioned in the open volume and comprising an amount of boron sufficient to stop the nuclear fission reaction or maintain the nuclear fission reaction at a sub-critical state.

6. The nuclear power system of claim 5 wherein the boron injection system comprises a boron container sized to hold or enclose the amount boron, and wherein the boron container is configured to release the amount of boron directly into the open volume in response to at least one of a predetermined temperature and pressure within the open volume such that the amount of boron is in fluid communication with an inner surface of the containment vessel.

7. A nuclear power system, comprising:
a reactor vessel that comprises a reactor core mounted within a volume of the reactor vessel, the reactor core comprising one or more nuclear fuel assemblies configured to generate a nuclear fission reaction;
a riser positioned above the reactor core;
a primary coolant flow path that extends from a bottom portion of the volume below the reactor core, through the reactor core, within the riser, and through an annulus between the riser and the reactor vessel back to the bottom portion of the volume;
a primary coolant that circulates through the primary coolant flow path to receive heat from the nuclear fission reaction and release the received heat to generate electric power in a power generation system fluidly or thermally coupled to the primary coolant flow path;
a chemical injection system in fluid communication with the primary coolant flow path; and
a control system communicably coupled to the chemical injection system, wherein the control system is configured to perform operations to control one or more parameters of the chemical injection system to control a power output of the nuclear fission reaction independent of any control rod assemblies during the normal operation, the operations comprising:
determining that the power output of the nuclear fission reaction is greater than an upper value or less than a lower value;
based on the determination, adjusting an amount of a chemical injected into the reactor core from the chemical injection system to adjust the power output of the nuclear fission reaction, wherein the operation of adjusting the amount of the chemical injected into the reactor core from the chemical injection system comprises at least one of:
increasing the amount of the chemical injected into the reactor core from the chemical injection system to decrease the power output of the nuclear fission reaction; or
decreasing the amount of the chemical injected into the reactor core from the chemical injection system to increase the power output of the nuclear fission reaction; and

subsequent to the adjustment, determining that the power output is within a range between the upper and lower values.

8. A method for controlling a nuclear fission reaction, comprising:
operating a nuclear power system to initiate a nuclear fission reaction, the nuclear power system comprising:
a reactor vessel that comprises a reactor core mounted within a volume of the reactor vessel, the reactor core comprising one or more nuclear fuel assemblies configured to initiate and maintain the nuclear fission reaction during a normal operation, wherein the reactor vessel does not include any control rod assemblies therein,
a riser positioned above the reactor core,
a primary coolant flow path that extends from a bottom portion of the volume below the reactor core, through the reactor core, within the riser, and through an annulus between the riser and the reactor vessel back to the bottom portion of the volume; and
a chemical injection system in fluid communication with the primary coolant flow path;

circulating a primary coolant through the primary coolant flow path to receive heat from the nuclear fission reaction;
transferring the received heat into a power generation system fluidly or thermally coupled to the primary coolant flow path to generate electric power; and
controlling a power output of the nuclear fission reaction independent of any control rod assemblies during the normal operation by:
determining that the power output of the nuclear fission reaction is greater than an upper value or less than a lower value;
based on the determination, adjusting an amount of a chemical injected into the reactor core from the chemical injection system

Assignees

• Nuscale Power Llc

Inventors

• Callaway Allyson
• Bristol Ben
• Rooks Kenneth
• Linik Larry

Classifications

• Y02E30/30

  Nuclear fission reactors · CPC title

• G21C9/024

  Rupture diaphragms · CPC title

• G21C9/022

  Reactor fuses · CPC title

• G21C9/033

  by an absorbent fluid · CPC title

• G21C7/24

  Selection of substances for use as neutron-absorbing material · CPC title