Using Gas Pressure to Safely Control Liquid Fuel Nuclear Reactors
This patent describes a method to control a nuclear reaction in liquid-fueled reactors by using gas pressure to adjust the amount of fuel solution in special pipes, ensuring the reactor always returns to a safe state if something goes wrong.
Original patent title: “Fail-safe reactivity compensation method for a nuclear reactor”
This patent describes a method to control a nuclear reaction in liquid-fueled reactors by using gas pressure to adjust the amount of fuel solution in special pipes, ensuring the reactor always returns to a safe state if something goes wrong. Granted to BWXT Technical Services Group in 2024 with 21 claims, and it is expected to expire in 2041.
Coverage
What does this patent actually cover?
This method controls the nuclear reaction in a solution nuclear reactor by manipulating the level of the liquid fuel. It involves placing one or more 'standpipes' in specific low-reactivity areas of the reactor vessel, as described in claimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 1(b). Each standpipe has an opening below the main solution level. A gas system, connected to these standpipes (claim 1(c)), uses gases like nitrogen or helium to control the fluid level within them (claim 1(d)). By changing the gas pressure, the amount of fuel solution inside the standpipes can be raised or lowered, which in turn adjusts the overall reactivity of the reactor. This system is designed to be 'fail-safe,' meaning any failure automatically restores the solution level to a safe condition, as stated in claim 5.
The gap
What does this patent NOT cover?
- Does not cover reactivity control methods that use mechanical movement of components, such as traditional control rods, within the reactor core (claimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 3).
- Does not cover nuclear reactors that use solid fuel elements instead of a liquid fuel solution (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 methods where standpipes are placed in high-reactivity areas of the nuclear reactor vessel (claimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 1(b)).
- Does not cover reactivity control methods that rely on chemical additives or temperature changes to adjust the reaction rate.
- Does not cover systems where the fail-safe mechanism does not involve the equalization of solution levels inside and outside the standpipes (claimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 6).
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
The cleverness lies in controlling nuclear reactivity without any moving mechanical parts within the reactor core. Instead, it uses gas pressure to precisely adjust the volume of liquid fuel in specific standpipes, creating a system that automatically defaults to a safe state if power or control is lost.
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
Aqueous Homogeneous Reactors (AHRs)
Solution-type research reactors
Advanced reactor designs exploring liquid fuels
Small modular reactors (SMRs) utilizing liquid fuel solutions
Why it matters
The bigger picture
This patent offers a way to control nuclear reactors that is inherently safer and simpler than traditional methods. By eliminating the need for moving mechanical parts, it reduces potential points of failure and simplifies reactor design. The fail-safe nature of the system means that in case of any malfunction, the reactor automatically moves to a safe, non-critical state, which is a significant advantage for reactor safety and reliability.
Filed
June 16, 2021
Granted
August 27, 2024
Market context
Who's building on this
Companies in this space
BWXT Technical Services Group Inc., the assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →, is a prominent player in nuclear technology, including advanced reactor designs and nuclear fuel. This patent aligns with ongoing efforts by companies like BWXT and others in the nuclear industry to develop safer, more efficient, and passively safe advanced reactors, particularly those exploring liquid fuel concepts for power generation or medical isotope production.
Market impact
This patent contributes to the ongoing development of advanced nuclear reactor designs, particularly those focused on enhanced safety and simplified operation. By offering a non-mechanical, fail-safe reactivity control method, it could help reduce the complexity and cost of future solution-type reactors. This could potentially enable broader adoption of these reactor types for various applications, from small modular reactors to specialized research facilities, by addressing key safety concerns.
Claim 1 — Plain English
What this patent covers
This method controls the nuclear reaction in a solution nuclear reactor by manipulating the level of the liquid fuel. It involves placing one or more 'standpipes' in specific low-reactivity areas of the reactor vessel, as described in claim 1(b). Each standpipe has an opening below the main solution level. A gas system, connected to these standpipes (claim 1(c)), uses gases like nitrogen or helium to control the fluid level within them (claim 1(d)). By changing the gas pressure, the amount of fuel solution inside the standpipes can be raised or lowered, which in turn adjusts the overall reactivity of the reactor. This system is designed to be 'fail-safe,' meaning any failure automatically restores the solution level to a safe condition, as stated in claim 5.
The clever bit
The cleverness lies in controlling nuclear reactivity without any moving mechanical parts within the reactor core. Instead, it uses gas pressure to precisely adjust the volume of liquid fuel in specific standpipes, creating a system that automatically defaults to a safe state if power or control is lost.
What it does not cover
- Does not cover reactivity control methods that use mechanical movement of components, such as traditional control rods, within the reactor core (claim 3).
- Does not cover nuclear reactors that use solid fuel elements instead of a liquid fuel solution (claim 1).
- Does not cover methods where standpipes are placed in high-reactivity areas of the nuclear reactor vessel (claim 1(b)).
- Does not cover reactivity control methods that rely on chemical additives or temperature changes to adjust the reaction rate.
- Does not cover systems where the fail-safe mechanism does not involve the equalization of solution levels inside and outside the standpipes (claim 6).
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
Early stage
Citation count
0/40
No citations yet
Claim breadth
14/20
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
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
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
$44K – $140K
Midpoint $88K · 14.9 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
21 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Angelo, P. L., Aase, S. B., & Nygaard, E. T. (2024). Using Gas Pressure to Safely Control Liquid Fuel Nuclear Reactors (U.S. Patent No. 12,073,952). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/12073952/fail-safe-reactivity-compensation-method-for-a-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 Using Gas Pressure to Safely Control Liquid Fuel Nuclear Reactors cover?
This patent describes a method to control a nuclear reaction in liquid-fueled reactors by using gas pressure to adjust the amount of fuel solution in special pipes, ensuring the reactor always returns to a safe state if something goes wrong.
Who owns patent US 12073952?
BWXT Technical Services Group owns this patent, granted in 2024.
When does this patent expire?
This patent is expected to expire on June 16, 2041, when the invention enters the public domain.
What problem does this patent solve?
This patent offers a way to control nuclear reactors that is inherently safer and simpler than traditional methods. By eliminating the need for moving mechanical parts, it reduces potential points of failure and simplifies reactor design. The fail-safe nature of the system means that in case of any malfunction, the reactor automatically moves to a safe, non-critical state, which is a significant advantage for reactor safety and reliability.
What does this patent NOT cover?
Does not cover reactivity control methods that use mechanical movement of components, such as traditional control rods, within the reactor core (claim 3).
Patent monitoring