Particle-Fueled Micro Reactor With Gravity Discharge Refueling

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Solution Overview

Problem

Conventional micro nuclear reactors face challenges in maintaining structural integrity and safety at high temperatures due to thermal expansion of block-shaped nuclear fuel, requiring frequent refueling and posing difficulties in output control and accident management.

Innovation Solution

A micro nuclear reactor design utilizing a core composed of small particles with a heat pipe and a power converter, featuring a valve for easy fuel discharge, a reflector for neutron control, and a rotary control drum for output regulation, along with a thermoelectric generator for power conversion, enhancing stability and safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If block-shaped nuclear fuel is used, then structural integrity is maintained, but thermal expansion causes damage at high temperatures and requires frequent refueling

Engineering Contradiction:

Improveoperational durationVSAvoidthermal expansion damage

Core Design Contradiction:

Duration of action of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The nuclear fuel is divided into small particles instead of using a single large block. This segmentation allows the fuel to expand and contract with temperature changes without causing irreversible damage to the reactor structure, while maintaining sufficient structural integrity for long-term operation.

Inventive Principle:

Principle #1Segmentation

2Ease of operation

If block-shaped nuclear fuel is used, then structural integrity is maintained, but refueling requires separate operations and is complex

Engineering Contradiction:

Improverefueling operationVSAvoidrefueling process complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The fuel is segmented into particles that can be easily discharged through a bottom outlet using gravity, eliminating the need for complex separate refueling operations. The particle size and gravity discharge mechanism simplify the entire refueling process.

Inventive Principle:

Principle #1Segmentation

3Ease of operation

If small particles are used for fuel, then refueling is easy and structural stability is improved, but output control becomes more difficult

Engineering Contradiction:

Improverefueling easeVSAvoidoutput control difficulty

Core Design Contradiction:

Ease of operationVSDifficulty of detecting and measuring

Solution Approach 1:

A control drum containing neutron-absorbing material is introduced as an intermediary mechanism. This drum can be rotated to control the nuclear reaction output by adjusting the position of neutron-absorbing material relative to the particle fuel, providing easy output control without complicating the refueling process.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Loss of energy

If conventional fuel design is used, then structural integrity is maintained, but heat removal efficiency is insufficient

Engineering Contradiction:

Improveheat removal efficiencyVSAvoidthermal load on structure

Core Design Contradiction:

Loss of energyVSTemperature

Solution Approach 1:

The heat pipe is extracted as a separate component that extends into the particle fuel core. This dedicated heat removal component efficiently transfers heat from the fuel particles to the surrounding structure, preventing excessive temperature buildup while maintaining structural integrity.

Inventive Principle:

Principle #2Taking out (Extraction)

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

The particle-based design ensures easy refueling, improved structural stability at high temperatures, and reliable power supply for several years without mechanical moving parts, suitable for various special-purpose applications.

Implementation Method 1

a heat pipe inserted in the core and transferring outwards heat generated by a nuclear reaction

Methodology Applied

Scientific EffectHeat pipe: Heat Pipe

Implementation Method 2

a heat pipe inserted in the core and transferring outwards heat generated by a nuclear reaction

Methodology Applied

Scientific EffectPhase change: Phase Change

Implementation Method 3

a heat pipe inserted in the core and transferring outwards heat generated by a nuclear reaction

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Implementation Method 4

a power converter receiving heat from a condenser of the heat pipe and converting thermal energy into electrical energy

Methodology Applied

Scientific EffectThermoelectric effect: Seebeck Effect

Implementation Method 5

a core filled with nuclear fuel and moderator which are formed of particles

Methodology Applied

Scientific EffectNuclear fission: Nuclear Fission

Implementation Method 6

the valve may be made of a material that melts upon reaching a predetermined temperature, and allows the nuclear fuel and the moderator to be discharged out of the core through the outlet

Methodology Applied

Scientific EffectMelting: Melting

Data Source

PatentUS12580088B2Micro nuclear reactor having a heat pipe extending into a core comprising fuel particles mixed with moderator particles, where the particles can be gravity discharged from the core through a bottom outlet

Publication Date: 2026.03.17 SEOUL NATIONAL UNIVERSITY R&DB FOUNDATION

AI summary

A micro nuclear reactor includes a core filled with nuclear fuel particles mixed with moderator particles. A heat pipe extends into the core and transfers heat generated by the core. A power converter receives heat from the heat pipe and converts thermal energy into electrical energy. A valve is configured to open and close an outlet located at a lower portion of the core. When the valve is open the nuclear fuel and the moderator are discharged by gravity from the core through the outlet.