Molten Salt Reactor Moderator Using Metal Hydroxides
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Solution Overview
Problem
Molten salt nuclear fission reactors face challenges with existing moderator materials, such as graphite and ZrHx, due to issues like large reactor core size, corrosion, and complex cooling requirements, which have hindered the commercialization of these reactors.
Innovation Solution
The use of metal hydroxides and deuteroxides as molten moderator salts, combined with a redox-element, to efficiently moderate neutrons and provide corrosion protection, allowing for a more compact reactor design and simplified cooling systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If graphite or ZrHx is used as moderator material, then neutron moderation is achieved, but reactor core size becomes large and corrosion issues arise
Solution Approach 1:
The patent changes the physical state of the moderator from solid (graphite, ZrHx) to liquid molten salt, enabling superior heat transfer properties and corrosion resistance while maintaining effective neutron moderation. The molten salt moderator allows for compact reactor core design due to its high density and efficient neutron scattering properties.
Solution Approach 2:
The patent employs composite molten salt formulations combining multiple salts (e.g., LiF, NaF, KF) with specific ratios to optimize both neutron moderation efficiency and corrosion resistance. This composite approach allows tuning of physical and chemical properties to simultaneously address moderation performance and material compatibility.
2Device complexity
If solid moderator materials are used, then neutron moderation is provided, but cooling requirements become complex
Solution Approach 1:
The molten salt moderator serves dual functions: it moderates neutrons through scattering and simultaneously acts as the primary cooling medium for heat removal from the reactor core. This multi-functionality eliminates the need for separate cooling systems, significantly reducing device complexity while maintaining reliable moderator performance.
Solution Approach 2:
The patent utilizes the fluid properties of molten salt to enable passive convection cooling and active pump-driven circulation systems. The liquid state allows efficient heat transport through hydraulic flow, replacing complex solid-state cooling mechanisms with simpler fluid-based thermal management.
3Object-affected harmful factors
If water is used as moderator, then neutron moderation is achieved, but high pressure operation is required leading to safety risks
Solution Approach 1:
The patent changes the moderator from water (liquid at ambient conditions) to molten salt (liquid at elevated temperatures), enabling operation at high temperatures without corresponding high pressures. This parameter change allows the system to achieve superior thermal efficiency while maintaining safety by operating at atmospheric or near-atmospheric pressures.
Solution Approach 2:
The molten salt moderator can be easily replaced or replenished if degradation occurs, providing a safety advantage over water systems where pressure containment failures have catastrophic consequences. The liquid molten salt can be drained or replaced without complex high-pressure containment requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables the construction of smaller, more efficient molten salt reactors with improved corrosion resistance and reduced material requirements, enhancing safety and operational efficiency.
Implementation Method 1
the energetic neutrons produced by fission exchange energy with a moderator and eventually interact with fissile material
Implementation Method 2
the redox-element has a reduction potential, which is larger than that of the inner tubing material or of the inner tubing material and the core container material
Data Source
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AI summary
A device adapted for producing energy by nuclear fission, the device comprising a core container of a core container material, which core container encloses an inner tubing of an inner tubing material, the inner tubing and/or the core container having an inlet and an outlet, the device further comprising a molten fuel salt with a fissionable material and a molten moderator salt comprising at least one metal hydroxide, at least one metal deuteroxide or a combination thereof and a redox-element having a reduction potential, which is larger than that of the inner tubing material or of the inner tubing material and the core container material, wherein the molten moderator salt is located in the core container and the molten fuel salt is located in the inner tubing, or wherein the molten fuel salt is located in the core container and the molten moderator salt is located in the inner tubing. The invention also relates to methods of controlling nuclear fission processes using the device and to the use of a molten salt comprising at least one metal hydroxide, at least one metal deuteroxide or a combination thereof and a redox-element for moderating fission neutrons created in a fission reaction process.