Lead Shielding Deformation in Radioactive Casks
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Solution Overview
Problem
Existing transport/storage casks for radioactive materials face deformation issues due to the low strength of lead gamma ray shielding layers, particularly during impact tests, leading to potential length shortening and clearance generation.
Innovation Solution
Incorporating a first metal member with high thermal conductivity and elasticity, such as aluminum or copper alloys, to reinforce gamma ray shielding blocks, and using a U-shaped metal member to wrap around the shielding blocks, along with a neutron shielding layer composed of organic materials like ethylene-propylene rubber, to enhance stability and prevent deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If lead block bodies are used for gamma ray shielding, then shielding performance is improved, but deformation resistance deteriorates
Solution Approach 1:
The patent applies composite materials by combining lead blocks with a metal member having higher elasticity limit. The lead block (302) provides gamma ray shielding while the metal member (301) provides structural strength and deformation resistance. This composite structure resolves the contradiction between shielding performance and deformation resistance.
Solution Approach 2:
The metal member acts as an intermediary between the lead block and the external environment. It mediates the mechanical stresses during impact events, preventing direct deformation of the lead block while maintaining the shielding function. The metal member absorbs and distributes impact forces before they reach the lead shielding material.
2Object-affected harmful factors
If lead block bodies are used for gamma ray shielding, then shielding performance is improved, but impact resistance deteriorates
Solution Approach 1:
The composite structure of metal member plus lead block provides both impact resistance and shielding performance. The metal member with higher elasticity limit absorbs impact energy through elastic deformation, protecting the lead block from impact damage while maintaining gamma ray shielding capability.
Solution Approach 2:
The metal member serves as a cushioning layer that absorbs impact energy before it reaches the lead block. During impact events, the metal member deforms elastically to absorb kinetic energy, preventing direct transmission of impact forces to the lead shielding material, thus preventing crushing and maintaining structural integrity.
3Object-affected harmful factors
If lead block bodies are used for gamma ray shielding, then shielding performance is improved, but structural stability deteriorates
Solution Approach 1:
The composite structure combines the density and shielding capability of lead with the structural stability and elasticity of the metal member. The metal member provides dimensional stability and prevents structural deformation during transport and handling operations, while the lead block maintains radiation shielding effectiveness.
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 solution effectively prevents deformation of gamma ray shielding blocks during impact tests and improves thermal conduction, ensuring the structural integrity and radiation shielding effectiveness of the cask.
Implementation Method 1
the first metal member has a higher thermal conductivity than the gamma ray shielding blocks. By adopting the first metal member having the above characteristic, the first metal member contributes to thermal conduction between the inner shell and the outer shell.
Implementation Method 2
the first metal member may have a higher elasticity limit than the gamma ray shielding blocks
Data Source
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AI summary
A transport/storage cask for a radioactive material has an inner shell (8), an outer shell (9) and a circular gamma ray shielding layer (10) and a circular neutron shielding layer (11) both of which are placed between the inner shell (8) and the outer shell (9). The gamma ray shielding layer (10) is formed by aligning a plurality of gamma ray shielding blocks (12) composed of lead in a block shape in the circumferential direction. The entire gamma ray shielding block (12) in the axial direction is covered with a copper tube (16) having a higher elasticity limit than the gamma ray shielding block (12). In the above transport/storage cask, the gamma ray shielding layer (10) composed of lead or a lead alloy is not easily deformed.