Boiling Water Reactor Fuel Rod Boost Zone Design
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Solution Overview
Problem
Conventional nuclear fuel rods have inefficiencies in power distribution and reactivity maintenance, leading to excess fuel and skewed power distribution within reactor cores, which are not adequately addressed by existing burnable poisons and uranium enrichment strategies.
Innovation Solution
A fuel rod design featuring a boost zone with enriched uranium at the bottom, a second zone with additional enriched uranium, and a third zone with natural uranium, where the enrichment of the boost zone is at least one percent, allowing for improved reactivity and cycle longevity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If burnable poisons are incorporated in fuel bundles to compensate for excess reactivity, then reactivity control is improved, but power distribution becomes skewed toward lower regions of the core
Solution Approach 1:
The patent applies local quality by creating a boost zone with elevated uranium enrichment (at least 1% U-235) specifically at the bottom of the fuel rod. This localized enrichment adjustment compensates for the power skew toward lower regions caused by burnable poisons, thereby balancing power distribution while maintaining reactivity control.
2Ease of manufacture
If conventional fuel rod designs with natural uranium blankets are used, then manufacturing is simplified, but the number of reactor cycles before fuel replacement is limited
Solution Approach 1:
The patent changes the enrichment parameter of the uranium fuel in the bottom zone from natural uranium (0.71% U-235) to enriched uranium (at least 1% U-235). This parameter change extends the duration of fuel action by improving neutron economy and delaying fuel depletion, thereby increasing the number of reactor cycles before fuel replacement is required.
3Power
If excess fuel and reactivity are loaded in reactor cores to maintain power through extended power cycles, then power maintenance is improved, but fuel efficiency decreases
Solution Approach 1:
The patent applies local quality by concentrating enriched uranium (at least 1% U-235) in the bottom boost zone of the fuel rod. This localized enrichment optimization improves neutron utilization efficiency in the region where power is naturally skewed, thereby maintaining power output through extended cycles while reducing overall fuel consumption and improving fuel efficiency.
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 design significantly increases the number of reactor cycles before fuel replacement, achieving a net gain in efficiency by optimizing uranium distribution and reducing the need for burnable poisons, counterintuitively improving reactor performance.
Implementation Method 1
The fuel rod includes first enriched uranium in a boost zone of the fuel rod, wherein the boost zone is arranged directly at a bottom of the fuel rod
Data Source
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AI summary
Disclosed are a fuel rod (300, 400) and a fuel bundle using the fuel rod (300, 400). The fuel rod (300, 400) may include first enriched uranium in a boost zone (310, 410) of the fuel rod (300, 400), wherein the boost zone (310, 410) may be arranged directly at a bottom of the fuel rod (300, 400). The fuel rod (300, 400) may also include second enriched uranium in a second zone (320, 420) of the fuel rod (300, 400), wherein the second zone (320, 420) is arranged over the boost zone (310, 410). The fuel rod (300, 400) may also include natural uranium in a third zone (330, 430) of the fuel rod, wherein the third zone (330, 430) is arranged over the second zone (320, 420). In this fuel rod(300, 400), a percent of enrichment of the enriched uranium in the boost zone (310, 410) is at least one percent.