Molten Chloride Salt Bath Control for Actinide Oxidation States

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Solution Overview

Problem

Molten salt reactors face challenges in controlling the state and degree of oxidation of actinides during the synthesis and reprocessing of nuclear fuel salts, particularly due to the low solubility of plutonium and high corrosion kinetics with fluoride salts, leading to inefficient fuel consumption and hazardous waste production.

Innovation Solution

A process involving the use of a judiciously selected mixture of gaseous or inert compounds to control the potential-oxoacidity of molten chloride salts, allowing for the predetermination of actinide states and oxidation levels by establishing potential-oxoacidity diagrams and introducing specific compounds to maintain the desired conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If fluoride molten salts are used, then heat transfer capability is improved, but plutonium solubility decreases and corrosion kinetics increase

Engineering Contradiction:
Improveheat transfer capabilityVSAvoidplutonium solubility
Core Design Contradiction:
TemperatureVSQuantity of substance

Solution Approach 1:

The invention changes the chemical composition parameter of the molten salt from fluoride to chloride base, fundamentally altering the solubility characteristics and corrosion behavior while maintaining operational temperature ranges

Inventive Principle:
Principle #35Parameter changes

2Temperature

If fluoride molten salts are used, then heat transfer capability is improved, but corrosion kinetics increase

Engineering Contradiction:
Improveheat transfer capabilityVSAvoidcorrosion kinetics
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The invention changes the chemical composition parameter of the molten salt from fluoride to chloride base, fundamentally altering the corrosion behavior while maintaining operational temperature ranges

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If actinide oxidation state is not controlled, then fuel synthesis is simplified, but fuel stability and waste characteristics deteriorate

Engineering Contradiction:
Improvefuel synthesis simplicityVSAvoidfuel stability
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The invention implements feedback control by continuously monitoring the oxidation state of actinides through potential measurements and adjusting the chemical environment (oxygen activity, chloride concentration) to maintain the desired oxidation state, ensuring fuel stability

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The invention controls the oxidation state by adjusting chemical parameters such as oxygen activity, chloride concentration, and potential, transforming an uncontrolled synthesis process into a precisely controlled one

Inventive Principle:
Principle #35Parameter changes

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

Enables precise control of actinide states and oxidation during fuel synthesis and reprocessing, enhancing fuel stability and reducing hazardous waste, particularly suitable for thorium and uranium-based reactors.

Implementation Method 1

The present invention proposes a method for controlling the state and/or degree of oxidation of one or more actinides... by bringing the bath into contact with a judiciously selected mixture of gaseous or inert compounds

Methodology Applied
Scientific EffectRedox reactions: Redox Reactions

Data Source

PatentEP4712103A1Process for controlling the actinide composition of a molten chloride salt bath
Publication Date: 2026.03.18 ALEXANDRE & GAVRILOFF
  • EP4712103A1 patent drawingFigure 1~2
  • EP4712103A1 patent drawingFigure 3
  • EP4712103A1 patent drawingFigure 4~5

AI summary

The present invention relates to a method for obtaining a chloride molten salt bath comprising at least one actinide in which the state and/or degree of oxidation of said at least one actinide are predetermined, comprising the following steps: (a) establishing, for said at least one actinide, its potential-oxoacidity diagram at a given temperature T in a chloride molten salt bath, (b) from the potential-oxoacidity diagram established in step (a), defining the potential-oxoacidity range in which said at least one actinide is in the predetermined state and/or degree of oxidation, (c) selecting at least three different compounds for fixing, at temperature T, the potential and oxoacidity of the chloride molten salt bath in the range defined in step (b), one of said at least three compounds being the chloride ion contained in the chloride molten salt bath.then (d) introduce into a bath of molten chloride salts comprising said at least one actinide at temperature T said at least three compounds selected in step (c). The present invention relates to the use of different mixtures or compositions in the preparation of nuclear fuel, during its operation or during its reprocessing.