Nuclear Fuel Storage Sleeves with Selective Boron Flats
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Solution Overview
Problem
The production of storage devices for nuclear fuel assemblies is costly due to the use of boron-containing flats in sleeves, which are expensive and impact the overall cost despite providing the necessary neutron absorption function.
Innovation Solution
A storage device design with a combination of boron-containing and boron-free flats in the sleeves, where boron-containing flats are used in specific configurations to maintain neutron absorption while reducing overall production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all flats in the sleeve are made with boron to ensure neutron absorption function, then the effective multiplication factor (Keff) requirement is met, but the production cost increases significantly
Solution Approach 1:
The patent applies local quality by differentiating the boron content in different flats of the sleeve. Specifically, opposite flats are made with boron (first flats) while adjacent flats are made without boron (second flats). This localized differentiation maintains neutron absorption performance where needed while reducing material costs in non-critical areas, directly resolving the contradiction between reliability and manufacturing cost.
2Reliability
If boron-containing flats are used in all positions to maintain subcriticality, then the safety requirement is fulfilled, but the overall production cost of the storage device increases
Solution Approach 1:
The invention implements local quality by strategically placing boron-containing flats only in opposite positions rather than all positions. This localized approach maintains the subcriticality safety requirement through proper neutron absorption in critical areas while significantly reducing the overall amount of expensive boron material needed, thereby lowering total production costs.
Solution Approach 2:
The patent applies partial action by using boron in only some flats (opposite ones) rather than all flats. This partial implementation is sufficient to maintain subcriticality safety while avoiding the excessive cost of boronizing every flat, thus resolving the contradiction between safety fulfillment and cost reduction.
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 heterogeneity of boron-containing and boron-free flats in the sleeves reduces manufacturing costs while maintaining high performance in terms of criticality and mechanical strength, thus addressing the cost issue of existing solutions.
Implementation Method 1
The second function relates to neutron absorption, and the concern to maintain the subcriticality of the storage device when loaded with fuel assemblies. This is achieved by using neutron absorbing materials, also called neutron poison materials, such as boron.
Data Source
AI summary
A storage device for transporting and/or storing nuclear fuel assemblies. The device includes a plurality of transverse structures separated by spacers. Sleeves pass through openings of at least one of the transverse structures. Each sleeve is made from flat structures and forms a housing that can receive a fuel assembly. At least one of these sleeves has an inner recess-delimiting surface formed in part by an inner surface of a first flat structure made with boron and an inner surface of a second flat structure made without boron.