Inertial energy coastdown for electromagnetic pump

Patent metadata

Field	Value
Publication number	US-12224642-B2
Application number	US-202117224115-A
Country	US
Kind code	B2
Filing date	Apr 6, 2021
Priority date	Aug 17, 2020
Publication date	Feb 11, 2025
Grant date	Feb 11, 2025

Abstract

A nuclear reactor is configured with a primary coolant loop for transferring heat away from the nuclear reactor core. In a shutdown event, the primary coolant pump may stop pumping primary coolant through the reactor core, resulting in decay heat buildup within the reactor core. An inertial energy coast down system can store kinetic energy while the nuclear reactor is operating and then release the stored kinetic energy to cause the primary coolant to continue to flow through the nuclear reactor core to remove decay heat. The inertial energy coast down system may include an impeller and a flywheel having a mass. During normal reactor operation, the flowing primary coolant spins up the impeller and flywheel, and upon a shutdown event where the primary coolant pump stops pumping, the flywheel and impeller can cause the primary coolant to continue to flow during a coast down of the flywheel and impeller.

First claim

What is claimed is:

1. A sodium-cooled nuclear reactor, comprising:
a reactor vessel;
a reactor core within the reactor vessel;
a primary heat exchanger within the reactor vessel;
a primary coolant loop configured to circulate primary coolant through the reactor core and the primary heat exchanger;
an electromagnetic pump in fluid communication with the primary coolant loop and configured to circulate primary coolant through the primary coolant loop; and
an inertial coast down system disposed along the primary coolant loop, the inertial coast down system comprising:
an impeller disposed within the primary coolant along the primary coolant loop; and
a flywheel disposed outside of the primary coolant, wherein the impeller is located upstream an inlet to the electromagnetic pump and downstream of the flywheel; and;

wherein the inertial coast down system is configured to operate independently from the electromagnetic pump and is configured to store rotational kinetic energy in the flywheel during operation of the sodium-cooled nuclear reactor and cause the flywheel to impart kinetic energy to the impeller, the impeller disposed within the primary coolant and causing primary coolant to flow along the primary coolant loop when the electromagnetic pump shuts down.

2. The sodium-cooled nuclear reactor as in claim 1 , wherein the impeller is located adjacent an inlet to the electromagnetic pump.

3. The sodium-cooled nuclear reactor as in claim 1 , wherein the flywheel is located within a cover gas region of the reactor vessel.

4. The sodium-cooled nuclear reactor as in claim 1 , wherein the impeller and flywheel are configured to release rotational kinetic energy to cause the primary coolant to flow when the electromagnetic pump stops circulating the primary coolant through the primary coolant loop.

5. The sodium-cooled nuclear reactor as in claim 4 , wherein the flywheel is configured to have a sufficient mass to allow the impeller to continue to rotate for greater than five seconds after the electromagnetic pump stops circulating the primary coolant.

6. The sodium-cooled nuclear reactor as in claim 1 , wherein the flywheel and the impeller are coaxial.

7. The sodium-cooled nuclear reactor as in claim 1 , wherein the flywheel is shaftless and defines a central opening about a rotational axis to allow natural circulation of primary coolant to flow therethrough.

8. The sodium-cooled nuclear reactor as in claim 1 , further comprising a battery configured to energize coils of the electromagnetic pump to create an electromagnetic field to drive the impeller upon shut down of the electromagnetic pump.

9. A method of providing a coast down flow in the sodium-cooled nuclear reactor of claim 1 , comprising:
causing the electromagnetic pump to flow an electrically conductive fluid through a fluid flow path;
extracting energy from the electrically conductive fluid by the impeller placed within the fluid flow path to cause the impeller to rotate;
transmitting a rotational energy from the impeller to the flywheel to cause the flywheel to rotate, the flywheel having a mass to store rotational energy; and
causing, upon a shutdown event of the electromagnetic pump, the flywheel to transmit the stored rotational energy to the impeller;
wherein the impeller rotates and causes the electrically conductive fluid to flow along the fluid flow path.

10. The method as in claim 9 , wherein the impeller is located near an inlet to the electromagnetic pump.

11. The method as in claim 9 , wherein the flywheel is located in a gaseous environment.

12. The method as in claim 9 , wherein the impeller and flywheel are coaxial.

13. The method as in claim 9 , wherein the flywheel is configured to transmit the stored rotational energy to the impeller for greater than three seconds.

14. The method as in claim 9 , wherein the flywheel is shaftless and defines a central opening to allow primary coolant to flow through the central opening along the fluid flow path by natural circulation.

15. The method as in claim 14 , further comprising creating, with the electromagnetic pump, a magnetic field that causes the impeller to spin.

16. The method as in claim 15 , wherein creating the magnetic field is performed by a battery during a time that the electromagnetic pump is not pumping.

Assignees

• Terrapower Llc

Inventors

• Corbin Robert A
• Edwards Michael J

Classifications

• H02K44/06 Primary

  Induction pumps · CPC title

• G21C15/12

  from pressure vessel; from containment vessel · CPC title

• G21C9/00

  Emergency protection arrangements structurally associated with the reactor {, e.g. safety valves provided with pressure equalisation devices}(emergency cooling arrangements G21C15/18) · CPC title

• G21C3/33

  Supporting or hanging of elements in the bundle (spacer grids G21C3/34); Means forming part of the bundle for inserting it into, or removing it from, the core; Means for coupling adjacent bundles · CPC title

• G21C1/326

  wherein the heat exchanger is disposed next to or beside the core · CPC title