Control rod damping system
AssigneeNuScale Power, LLC
InventorRoss Douglas Snuggerud
Life of this patent
Estimating the term…
Abstract
A damping area or “dash pot” on the upper ends of control rods absorb energy from dropped control rod assemblies without narrowing the diameter of guide tubes. As a result, coolant can freely flow through the guide tubes reducing boiling water issues. The dampening area reduces a separation distance between an outside surface of the control rod and an inside surface of the guide tubes decelerating the control rods when entering a top end of the guide tubes. In another example, the dampening area may be located on a drive shaft. The dampening area may have a larger diameter than an opening in a drive shaft support member that decelerates the drive shaft when dropped by a drive mechanism.
Claims20
A fuel control system for a nuclear reactor having a reactor vessel housing a reactor core, the fuel control system comprising:
- a support member positioned within the reactor vessel and including an opening;
- and
- a drive shaft extending through the opening, wherein the drive shaft includes-
- an upper portion positioned to be coupled to a drive mechanism, wherein the upper portion has a first diameter;
- a lower portion positioned to be coupled to a control rod assembly configured to control a nuclear reaction of the reactor core, wherein the lower portion has a second diameter less than the first diameter;
- and
- a damping portion positioned between the upper portion and the lower portion,
- wherein the damping portion has an upper end portion and a lower end portion, and wherein the damping portion has a third diameter that decreases from the first diameter at the upper end portion to the second diameter at the lower end portion.
A fuel control system for a nuclear reactor having a reactor vessel housing a reactor core, the fuel control system comprising:
- a drive shaft including-
- an upper portion positioned to be coupled to a drive mechanism;
- a lower portion positioned to be coupled to a control rod assembly configured to control a nuclear reaction of the reactor core;
- and
- a damping portion positioned between the upper portion and the lower portion,
- wherein the damping portion has a first conical shape that decreases in diameter in a direction from the upper portion toward the lower portion;
- and
- a support member positioned within the reactor vessel and including an opening,
- wherein the opening is positioned to receive the drive shaft therethrough, and
- wherein the opening has a second conical shape that decreases in diameter in the direction from the upper portion toward the lower portion.
A nuclear reactor system, comprising:
- a reactor vessel;
- a coolant positioned within the reactor vessel;
- a reactor core positioned within the reactor vessel and configured to heat the coolant;
- a riser positioned within the reactor vessel and positioned to direct a portion of the coolant heated by the reactor core upward away from the reactor core;
- a support member positioned within the reactor vessel and including an opening;
- and
- a drive shaft extending through the opening, wherein the drive shaft includes-
- an upper portion positioned to be coupled to a drive mechanism, wherein the upper portion has a first diameter;
- a lower portion positioned to be coupled to a control rod assembly configured to control a nuclear reaction of the reactor core, wherein the lower portion has a second diameter less than the first diameter;
- and
- a damping portion positioned between the upper portion and the lower portion,
- wherein the damping portion has an upper end portion and a lower end portion, and wherein the damping portion has a third diameter that decreases from the first diameter at the upper end portion to the second diameter at the lower end portion.
Dependencies are inferred from the claim text.