Radioactive Waste Vitrification Using Decay Heat
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Solution Overview
Problem
Conventional methods for solidifying high-level radioactive waste using glass result in non-uniform products due to the use of water, which can lead to hydrogen gas generation and leakage of radioactive nuclides, and require large melting facilities, whereas hydrothermal methods inefficiently use decay heat to evaporate water rather than uniformly heating the waste.
Innovation Solution
A method involving the placement of a vessel containing radioactive waste and glass raw materials in an adiabatic area where radiation-generated heat uniformly melts the glass raw materials, eliminating the need for a melting facility and ensuring a uniform vitrified waste product.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If hydrothermal solidification method is used to utilize decay heat, then melting facility is not needed, but water is evaporated and solidified body becomes non-uniform
Solution Approach 1:
The patent removes water from the solidification system, extracting the harmful element that causes non-uniform heating and hydrogen generation. By using only glass raw materials and radioactive waste without added water, the system achieves uniform heating through decay heat while preventing water evaporation and hydrogen gas generation.
Solution Approach 2:
The patent employs self-service by utilizing the decay heat generated by the radioactive waste itself to melt the glass raw materials and form the solidified body. This eliminates the need for external melting facilities while ensuring uniform heating throughout the mixture, as the heat source is distributed within the waste material.
2Ease of manufacture
If cement solidification is used, then processing is simple and inexpensive, but hydrogen gas is generated by radiolysis of moisture
Solution Approach 1:
The patent converts the harmful effect of radiolysis into a beneficial process by replacing water-based cement solidification with water-free glass solidification. The decay heat, which would otherwise be wasted, is converted into useful thermal energy to melt the glass and bind the radioactive waste, creating a stable solidified body without hydrogen gas generation.
3Object-generated harmful factors
If conventional glass solidification is used, then hydrogen gas is not generated, but large melting facility is required
Solution Approach 1:
The radioactive waste serves its own heating function by utilizing its decay heat to melt the glass raw materials. This self-heating mechanism eliminates the need for external melting facilities, making the process simpler and more compact while maintaining the safety benefits of glass solidification without hydrogen gas generation.
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 allows for the production of a uniform vitrified radioactive waste without the need for a melting facility, reducing the risk of hydrogen gas generation and leakage, while efficiently utilizing decay heat for uniform heating.
Implementation Method 1
heating the radioactive waste and glass raw materials in the first vessel existing in the adiabatic area in the second vessel by heat generated by radiation emitted from the radioactive nuclides
Implementation Method 2
disposing the first vessel in which the radioactive waste and glass raw materials exist, in an adiabatic area in a second vessel
Implementation Method 3
producing a vitrified radioactive waste by melt of the heated glass raw materials
Data Source
Figure 1~2
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Figure 5
AI summary
In a radioactive waste solidification method, radioactive waste (for example, zeolite to which Cs-137 was adsorbed) and glass raw materials (soda lime glass) are supplied into the solidifying vessel (3). The solidifying vessel (3) filled with the radioactive wastes and glass raw materials is disposed in an adiabatic vessel (7). A lid is attached to the adiabatic vessel (7) to seal it. The radioactive waste and glass raw materials in the adiabatic vessel (7) are heated by thermal energy generated due to radiation emitted from Cs-137. The glass raw materials are melted and osmose in clearances among the radioactive waste, producing a vitrified radioactive waste. Since the radioactive waste and glass raw materials are disposed in the adiabatic vessel (7), they are uniformly heated and a uniform vitrified radioactive waste is obtained. No melting facility is needed. The radioactive waste solidification method can produce a uniform vitrified radioactive waste through uniform heating without having to use a melting facility.