Core Catcher Cantilever Truss Welding for Predictable Failure
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Solution Overview
Problem
Existing methods for manufacturing core catcher cantilever trusses result in structures with equal strength in all radial directions, leading to unpredictable destruction during beyond-design-basis accidents, seismic events, and impact effects from the guide plate.
Innovation Solution
A method for manufacturing a core catcher cantilever truss involves forming two symmetrical parts with outer, middle, and inner half-shells connected by radial and parallel force ribs, and upper and lower semicircular force plates, with specific welding patterns to create structural non-uniformity and concentrate stresses at thinner welded joints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the cantilever truss is manufactured with equal strength in all radial directions, then the structure is uniformly strong, but the destruction becomes unpredictable during beyond-design-basis accidents
Solution Approach 1:
The patent applies local quality by creating non-uniform welded joints with different thicknesses at specific locations (outer, inner, and intermediate vertical welded joints have different thicknesses than horizontal welded joints). This localized variation in joint thickness creates predetermined weak zones that will fail first under extreme loads, making the destruction pattern predictable while maintaining overall structural strength through the thicker joints in other areas.
2Ease of manufacture
If the welded joints are made with uniform thickness, then the manufacturing is simpler, but the stress distribution during extreme events becomes uncontrolled
Solution Approach 1:
The patent implements local quality by specifying different thicknesses for welded joints at different locations. The outer, inner, and intermediate vertical welded joints have different thicknesses compared to horizontal welded joints, creating localized stress concentration zones. This allows controlled stress distribution during extreme events while maintaining relatively simple manufacturing procedures.
3Ease of manufacture
If the cantilever truss has symmetric structure, then the manufacturing is easier, but the deformation localization during thermal expansion is not optimized
Solution Approach 1:
The patent applies asymmetry by introducing non-uniform welded joint thicknesses within the symmetric overall structure. While the cantilever truss maintains symmetric geometry for ease of manufacture, the welded joints connecting symmetrical parts have varying thicknesses (outer, inner, intermediate vertical joints differ from horizontal joints), creating asymmetric stress distribution that localizes deformations in specific zones during thermal expansion.
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 method ensures predictable destruction of bearing elements during extreme events, enhancing the reliability of the core catcher by localizing deformations and concentrating stresses within the welded joints of lesser thickness.
Implementation Method 1
two symmetrical parts of the cantilever truss are formed, each of which is made of outer, middle, and inner half-shells, which are connected between each other with radial and parallel force ribs, as well as upper and lower semicircular force plates by welding
Data Source
AI summary
The invention related to technology for manufacturing safety systems of nuclear power plants. A method for manufacturing a core catcher cantilever truss is characterized in that two symmetrical parts of the cantilever truss are formed, each of which is made of outer, middle, and inner half-shells, which are connected between each other with radial and parallel force ribs, as well as upper and lower semicircular force plates by welding, with formation of parallel and radial sectors. After that the above-mentioned two symmetrical parts are connected to each other by welding in the area of two parallel sectors located on one Cartesian axis, so that the upper horizontal connection connects the upper semicircular force plates, a lower horizontal welded joint connects the lower semicircular force plates, outer, inner, and middle vertical welded joints connect the outer, inner, and middle half-shells.