Ceramic Waste Form Stabilizing Chloride Ions in Nuclear Fuel
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Solution Overview
Problem
Borosilicate glass waste forms used in nuclear fuel management degrade over time due to chloride ions present in active metal salt waste, compromising their performance and safety in long-term storage.
Innovation Solution
A method is developed to create a ceramic waste form by combining active metal salt waste with rare earth metal waste and raw materials, heating them to form a homogenous mixture, and then processing at specific temperatures to produce a sodalite-based ceramic waste form that encapsulates chloride ions, using zeolite to occlude chloride anions and glass to bind the sodalite, thereby stabilizing the waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If borosilicate glass waste form is used to immobilize active metal salt waste, then the waste can be disposed of, but the chloride ions in the waste cause degradation of the glass over time, compromising performance and safety
Solution Approach 1:
The patent extracts chloride ions from the waste stream by combining active metal salt waste with rare earth metal waste to form a waste salt, then heating to approximately 500°C to remove chloride ions before blending with raw materials. This extraction prevents chloride ions from degrading the ceramic waste form during long-term storage.
Solution Approach 2:
The patent creates a composite ceramic waste form by combining processed waste salt with raw materials including glass and other components. The resulting composite material encapsulates remaining chloride ions and provides a stable matrix that resists degradation, solving the problem of chloride-induced glass deterioration.
2Reliability
If heating to high temperature is applied to form ceramic waste form, then the waste is stabilized, but energy consumption increases
Solution Approach 1:
The patent applies preliminary heating to approximately 500°C to the waste salt before blending with raw materials. This pre-treatment removes chloride ions and prepares the waste salt for subsequent ceramic formation, reducing the total energy required during the final high-temperature ceramic processing step.
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 method effectively stabilizes active nuclear fuel metals in a ceramic waste form, enhancing the durability and safety of high-level waste disposal by preventing chloride ion-induced degradation, ensuring long-term stability and safety of the waste form.
Implementation Method 1
The waste salt is then heated to approximately 500° C.
Implementation Method 2
The raw materials are also heated to approximately 500° C.
Implementation Method 3
The homogenous waste mixture is heated to a first predetermined temperature for a predetermined amount of time, creating a ceramic waste form.
Implementation Method 4
The ceramic waste form is cooled to a second predetermined temperature.
Data Source
AI summary
According to one aspect of the invention, a method to create a ceramic waste form from used nuclear fuel. An active metal salt waste, a rare earth metal waste, and raw materials are received. The active metal salt waste is combined with the rare earth metal waste, forming a waste salt. The waste salt is then heated to approximately 500° C. The raw materials are also heated to approximately 500° C. The waste salt and raw materials are then blended to form a homogenous waste mixture. The homogenous waste mixture is heated to a first predetermined temperature for a predetermined amount of time, creating a ceramic waste form. The ceramic waste form is cooled to a second predetermined temperature.