How a Nuclear Reactor's Rotating Drum Controls Power
This patent describes a rotating drum for nuclear reactors, especially mobile ones, that uses tubes filled with different materials to absorb or scatter neutrons, precisely controlling the reactor's power output.
Original patent title: “Control drum for a mobile nuclear reactor”
This patent describes a rotating drum for nuclear reactors, especially mobile ones, that uses tubes filled with different materials to absorb or scatter neutrons, precisely controlling the reactor's power output. Granted to GE Hitachi Nuclear Energy Americas in 2022 with 22 claims and 8 forward citations, and it is expected to expire in 2039.
Coverage
What does this patent actually cover?
This patent describes a specialized "control drum" designed for nuclear reactors, particularly mobile ones. The drum has an outer shell and an inner shell, with several tubes held in place by perforated baffle plates (ClaimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 1). Some tubes contain "neutron absorbing material" like boron or hafnium, which slow down or stop the nuclear reaction. Other tubes contain "neutron scattering material" like beryllium or graphite, which reflect neutrons back into the fuel, speeding up the reaction (Claim 1). A drive mechanism rotates the drum (Claim 5). By turning the drum, either the neutron-absorbing tubes or the neutron-scattering tubes can be positioned to face the nuclear fuel rods, allowing precise control over the reactor's power level (Claim 5). For example, if the reactor needs to reduce power, the drum rotates to expose the neutron-absorbing tubes to the fuel. If the drive mechanism fails, a torsional spring automatically rotates the drum to a "fail-safe state" where the neutron-absorbing tubes face the fuel, shutting down the reaction (Claim 6, 7).
The gap
What does this patent NOT cover?
- Does not cover control methods that use only neutron absorbing materials without also including neutron scattering materials within the same control drum (ClaimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 1).
- Does not cover control drums where the tubes are not supported by baffle plates with perforations (ClaimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 1).
- Does not cover control drums that lack a specific fail-safe mechanism, such as a torsional spring, to automatically rotate to a neutron-absorbing position upon drive failure (ClaimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 6, 7).
- Does not cover control drums that are not designed for horizontal mounting in a reflector region (ClaimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 9).
- Does not cover control drums without a magnetic coupling between the drive shaft and the inner shell (ClaimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 5).
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
The clever bit is combining both neutron absorbing and neutron scattering materials within the *same* rotating control drum, allowing for both reduction and enhancement of the nuclear reaction by simply rotating the drum. This provides a compact and potentially more responsive control mechanism than systems relying solely on absorbing elements. The integrated fail-safe is also a key innovation.
The Patent Drawing
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Small Modular Reactors (SMRs)
Microreactors
Naval nuclear propulsion systems
Experimental mobile nuclear power units
Why it matters
The bigger picture
This patent focuses on a critical component for controlling nuclear reactors, especially those designed to be mobile. Mobile nuclear reactors, while still largely in development, could provide power for remote locations, space missions, or military applications. Precise and reliable control, including robust fail-safe mechanisms, is essential for the safe operation of any nuclear system, making this design relevant for future compact reactor technologies.
Filed
December 31, 2019
Granted
August 16, 2022
Market context
Who's building on this
Companies in this space
GE Hitachi Nuclear Energy Americas, the assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →, is a major player in the nuclear energy sector, developing advanced reactor designs including Small Modular Reactors (SMRs). Other companies and national labs involved in advanced reactor development, such as TerraPower, NuScale Power, and government research institutions, are likely exploring similar control mechanisms for compact and mobile reactor designs.
Market impact
This patent contributes to the ongoing development of advanced nuclear reactor designs, particularly for the emerging market of mobile and small modular reactors. By offering a compact and robust control mechanism with an integrated fail-safe, it could enable more flexible and safer deployment of nuclear power in diverse applications, potentially reducing the footprint and complexity of future reactor control systems.
Claim 1 — Plain English
What this patent covers
This patent describes a specialized "control drum" designed for nuclear reactors, particularly mobile ones. The drum has an outer shell and an inner shell, with several tubes held in place by perforated baffle plates (Claim 1). Some tubes contain "neutron absorbing material" like boron or hafnium, which slow down or stop the nuclear reaction. Other tubes contain "neutron scattering material" like beryllium or graphite, which reflect neutrons back into the fuel, speeding up the reaction (Claim 1). A drive mechanism rotates the drum (Claim 5). By turning the drum, either the neutron-absorbing tubes or the neutron-scattering tubes can be positioned to face the nuclear fuel rods, allowing precise control over the reactor's power level (Claim 5). For example, if the reactor needs to reduce power, the drum rotates to expose the neutron-absorbing tubes to the fuel. If the drive mechanism fails, a torsional spring automatically rotates the drum to a "fail-safe state" where the neutron-absorbing tubes face the fuel, shutting down the reaction (Claim 6, 7).
The clever bit
The clever bit is combining both neutron absorbing and neutron scattering materials within the *same* rotating control drum, allowing for both reduction and enhancement of the nuclear reaction by simply rotating the drum. This provides a compact and potentially more responsive control mechanism than systems relying solely on absorbing elements. The integrated fail-safe is also a key innovation.
What it does not cover
- Does not cover control methods that use only neutron absorbing materials without also including neutron scattering materials within the same control drum (Claim 1).
- Does not cover control drums where the tubes are not supported by baffle plates with perforations (Claim 1).
- Does not cover control drums that lack a specific fail-safe mechanism, such as a torsional spring, to automatically rotate to a neutron-absorbing position upon drive failure (Claim 6, 7).
- Does not cover control drums that are not designed for horizontal mounting in a reflector region (Claim 9).
- Does not cover control drums without a magnetic coupling between the drive shaft and the inner shell (Claim 5).
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
Patent enters public domain
PatentBrief Score
Impact Score
Strong
Citation count
19/40
Early citations
Claim breadth
15/20
Broad claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more →
Recency
20/20
Granted within 5 years
Assignee scale
20/20
Major company or institution
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$112K – $359K
Midpoint $225K · 13.4 yr remaining · industry ×1.5
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Claim text not yet imported for this patent
The original legal language
Original claims
22 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
NELSON, D. S. (2022). How a Nuclear Reactor's Rotating Drum Controls Power (U.S. Patent No. 11,417,435). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/11417435/control-drum-for-a-mobile-nuclear-reactor
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does How a Nuclear Reactor's Rotating Drum Controls Power cover?
This patent describes a rotating drum for nuclear reactors, especially mobile ones, that uses tubes filled with different materials to absorb or scatter neutrons, precisely controlling the reactor's power output.
Who owns patent US 11417435?
GE Hitachi Nuclear Energy Americas owns this patent, granted in 2022.
When does this patent expire?
This patent is expected to expire on December 31, 2039, when the invention enters the public domain.
What is patent US 11417435 cited by?
This patent has been cited by 8 later patents that build on its ideas.
What problem does this patent solve?
This patent focuses on a critical component for controlling nuclear reactors, especially those designed to be mobile. Mobile nuclear reactors, while still largely in development, could provide power for remote locations, space missions, or military applications. Precise and reliable control, including robust fail-safe mechanisms, is essential for the safe operation of any nuclear system, making this design relevant for future compact reactor technologies.
What does this patent NOT cover?
Does not cover control methods that use only neutron absorbing materials without also including neutron scattering materials within the same control drum (Claim 1).
Patent monitoring