Blended Nuclear Fuel for Pressurized Heavy Water Reactors
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Solution Overview
Problem
Nuclear fuels with high or low uranium content, as well as recycled uranium, are not viable for use in many reactors due to inappropriate fissile content levels, particularly the presence of impurities which prevent their use in pressurized heavy water reactors.
Innovation Solution
Blending recycled uranium with depleted uranium or natural uranium to achieve a fissile content of uranium-235 within a suitable range for use in nuclear reactors, specifically creating fuel bundles with specific fissile content ratios to optimize fuel burnup and reduce coolant void reactivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If recycled uranium is used as nuclear fuel, then fuel utilization and cost savings are improved, but the fissile content is inappropriate for many reactors
Solution Approach 1:
The patent combines recycled uranium with depleted uranium or natural uranium to create a blended fuel composition. This merging allows the fuel to achieve appropriate fissile content levels (e.g., 0.71-0.72 wt% U-235) suitable for pressurized heavy water reactors while still utilizing recycled uranium material, thus resolving the contradiction between fuel utilization and appropriate fissile content.
Solution Approach 2:
The patent changes the fissile content parameter of recycled uranium by blending it with depleted or natural uranium. This parameter adjustment transforms the fuel composition to meet reactor requirements, enabling recycled uranium to be used in pressurized heavy water reactors that previously could not accommodate it due to inappropriate fissile content levels.
2Productivity
If recycled uranium with impurities is used, then fuel recycling is improved, but reactor compatibility deteriorates
Solution Approach 1:
The patent changes the compositional parameters of recycled uranium by blending it with depleted or natural uranium. This adjustment modifies the fuel properties to achieve compatibility with pressurized heavy water reactors, resolving the contradiction between fuel recycling and reactor compatibility by making the recycled fuel adaptable to specific reactor types.
3Power
If high fissile content fuel is used, then energy production is improved, but fuel burnup control and coolant void reactivity increase
Solution Approach 1:
The patent optimizes the fissile content parameter to a specific range (e.g., 0.71-0.72 wt% U-235) that balances energy production with fuel burnup control and coolant void reactivity. This parameter optimization resolves the contradiction by achieving appropriate power levels while maintaining safety and control characteristics suitable for pressurized heavy water reactors.
Data Source
AI summary
Fuel bundles for a nuclear reactor are described and illustrated, and in some cases includes fuel elements each having a first fuel component of recycled uranium, and a second fuel component of at least one of depleted uranium and natural uranium blended with the first fuel component, wherein the blended first and second fuel components have a first fissile content of less than 1.2% wt of 235U. Other fuel bundles are also described and illustrated, and include a first fuel element including recycled uranium, the first fuel element having a first fissile content of no less than 0.72 wt % of 235U; and a second fuel element including at least one of depleted uranium and natural uranium, the second fuel element having a second fissile content of no greater than 0.71 wt % of 235U.