Nuclear Fuel Pellets with Ba-Al-Si Oxide Trapping Agents
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current nuclear fuel pellets face challenges in independently trapping and stabilizing cesium (Cs) and iodine (I) fission gases, leading to volatilization and stress corrosion cracking, with existing trapping materials losing functionality at high temperatures and requiring pre-trapped Cs for effective I trapping.
Innovation Solution
Incorporating a trapping material composed of silicon (Si), aluminum (Al), and barium (Ba) oxides in nuclear fuel pellets, which are sintered to form a composition that selectively traps Cs and I, maintaining stability and trapping efficiency even at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional trapping materials are used to trap fission gases, then trapping function is provided at low temperatures, but trapping function is lost at high temperatures during hot sintering process
Solution Approach 1:
The patent uses a composite material system consisting of UO2 nuclear fuel particles combined with specific trapping material particles (BaAl2O4, BaSiO3, or Ba2SiO4) having controlled particle sizes (0.1-10 μm). This composite structure allows the trapping material to maintain its crystalline structure and trapping function at high sintering temperatures while effectively trapping fission gases during reactor operation.
Solution Approach 2:
The patent changes the chemical composition parameters by selecting specific barium-containing compounds (BaAl2O4, BaSiO3, Ba2SiO4) with appropriate melting points and thermal stabilities. By controlling the particle size parameters (0.1-10 μm) and composition ratios (0.01-1 wt% of total fuel), the material maintains trapping functionality throughout the temperature range from sintering to reactor operation.
2Reliability
If Cs trapping material is used to trap Iodine, then I can be trapped as CsI, but trapping probability of I is lowered and CsI volatilizes at high temperatures
Solution Approach 1:
The patent extracts the iodine trapping function from the CsI formation mechanism and assigns it to barium-containing compounds instead. By using BaAl2O4, BaSiO3, or Ba2SiO4 as the trapping material, iodine is trapped directly by barium to form stable barium iodide compounds, eliminating the need for CsI formation and avoiding the associated high-temperature volatilization problems.
Solution Approach 2:
The patent replaces the unstable CsI trapping mechanism with stable barium-containing compounds that maintain their trapping function at high temperatures. The barium-based trapping materials provide long-term stability during reactor operation, preventing the volatilization issues that plague CsI-based approaches.
3Reliability
If trapping material is added to nuclear fuel pellets, then fission gas trapping is improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges the trapping material particles with the nuclear fuel particles into a single composite pellet structure. Both UO2 fuel particles and trapping material particles are mixed together and sintered in one hot press step, eliminating the need for separate trapping material fabrication and assembly steps. This integrated approach maintains trapping efficiency while simplifying the overall manufacturing process.
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 solution enables independent and efficient trapping of Cs and I, reducing volatilization and stress corrosion cracking, while maintaining trapping efficiency and stability, thus improving nuclear fuel pellet performance and safety.
Implementation Method 1
a Cs trapping material has been developed based on a SiO2-based material... the development of trapping materials capable of stably trapping and storing Cs
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention relates to a nuclear fuel pellet and a method for manufacturing same and, more particularly, to a nuclear fuel pellet comprising a trapping agent for fission gases and a method for manufacturing same. The nuclear fuel pellet of the present invention comprises: a nuclear fuel; and a trapping agent for fission gases, wherein the trapping agent for fission gases comprises an oxide containing at least one element selected from the group consisting of silicon (Si), aluminum (Al), and barium (Ba), and thus can exhibit an excellent trapping ability which is selective and independent with respect to fission gases.