Nuclear Fuel Storage Housing Boron Segmentation
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Solution Overview
Problem
The high production cost of storage devices for nuclear fuel assemblies due to the costly embodiment of structural assemblies with boron notches, which are necessary for thermal transfer, neutron absorption, and mechanical strength, particularly in 'free fall' tests.
Innovation Solution
The use of a storage device with adjacent housings produced using flat bars with notches, where at least some housings are formed by combining borated and non-borated flat bars, reducing the overall boron content while maintaining equivalent performance, thereby lowering production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all flat bars are produced with boron to ensure neutron absorption and subcriticality, then the neutron absorption function is fulfilled, but the manufacturing cost increases significantly
Solution Approach 1:
The patent applies local quality by differentiating the boron content in flat bars based on their position within the housing. Flat bars in contact with fuel assemblies contain boron for neutron absorption, while flat bars not in direct contact with fuel can be produced without boron, reducing overall manufacturing cost while maintaining safety
Solution Approach 2:
The housing is segmented into different regions with different material requirements. The patent divides flat bars into borated flat bars and non-borated flat bars, allowing selective application of boron only where neutron absorption is critical, thus resolving the contradiction between reliability and manufacturing cost
2Strength
If flat bars with notches are used to form structural assemblies, then mechanical strength and thermal transfer are improved, but the production cost increases due to the complexity of forming notches with boron
Solution Approach 1:
The structural assembly is segmented into borated and non-borated flat bars. Non-borated flat bars can be manufactured with notches more easily and at lower cost, while borated flat bars are used only where both structural strength and neutron absorption are required
Solution Approach 2:
Different regions of the structural assembly have different material properties. Flat bars requiring high mechanical strength and thermal transfer capability are produced with boron and notches, while other flat bars use simpler, lower-cost materials without boron
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 reduces manufacturing costs while maintaining high performance in terms of criticality and mechanical strength, ensuring effective thermal transfer, neutron absorption, and compliance with safety requirements.
Implementation Method 1
The second function relates to neutron absorption, and the concern of maintaining the subcriticality of the storage device when the latter is loaded with fuel assemblies. This is carried out using neutron-absorbing materials, such as boron.
Implementation Method 2
This consists firstly of the function of thermal transfer of the heat released by the fuel assemblies. Generally, aluminium or one of the alloys thereof is used, due to the good thermal conduction properties thereof.
Data Source
AI summary
A storage device for storing and/or transporting nuclear fuel assemblies. The storage device includes a number N of adjacent recesses. Some of the recesses created by means of notched, intersecting and stacked plates. In at least one transverse plane, at least one of the adjacent recesses has an inner surface which defines the recess. The adjacent recess being formed in part by a first surface of a first notched plate made with boron and a first surface of a second notched plate made without boron.