Flexible Radiation Shield for Nuclear Expansion Gaps
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional radiation shielding methods fail to effectively protect personnel from variable radiation exposure in expansion gaps, particularly around fuel transfer tubes in nuclear power plants, due to temperature-induced changes in gap sizes, leading to potential lethal doses of radiation.
Innovation Solution
A flexible radiation shield comprising a hollow, flexible outer bladder filled with a shielding fluid that accommodates varying gap sizes, maintaining shielding integrity and using a make-up tank to control fluid volume, supported by a two-ply bladder system with anti-sag baffles and puncture-resistant materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional rigid radiation shielding is used in expansion gaps, then shielding effectiveness is maintained under fixed conditions, but the shield cannot accommodate temperature-induced gap variations, leading to radiation exposure risks
Solution Approach 1:
The radiation shield transitions from a rigid structure to a flexible, dynamic system using a pneumatic or hydraulic bladder that can expand and contract to accommodate varying gap sizes while maintaining continuous shielding coverage
Solution Approach 2:
The shield uses pressure-controlled fluid bladders that change their physical parameters (volume, pressure) to adapt to temperature-induced gap variations, maintaining shielding effectiveness across different operational conditions
2Adaptability or versatility
If flexible materials are used to accommodate gap variations, then adaptability improves, but shielding effectiveness may be compromised due to material limitations
Solution Approach 1:
The shield combines flexible bladder materials with dense radiation-shielding materials (lead, steel, or concrete) to create a composite structure that maintains both flexibility for gap accommodation and sufficient density for radiation attenuation
Solution Approach 2:
The flexible bladder is nested within a rigid support structure or between fixed shielding elements, allowing the flexible component to adapt to gap variations while being constrained within boundaries that maintain overall shielding geometry
3Adaptability or versatility
If a flexible bladder system is used to fill the expansion gap, then gap accommodation is achieved, but system complexity increases due to fluid control requirements
Solution Approach 1:
The bladder system is designed to self-regulate through pressure equalization or thermal expansion of the enclosed fluid, automatically adapting to gap variations without requiring external control systems
Solution Approach 2:
The fluid-filled bladder serves multiple functions simultaneously: providing radiation shielding, accommodating gap variations, and acting as a pressure equalization mechanism, reducing the need for separate control systems
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 flexible radiation shield reduces radiation dose rates outside the gap, maintains shielding integrity across varying gap sizes, and provides a passive, long-lasting solution with immediate integrity indication, reducing the risk of worker overexposure and accommodating thermal expansion without the need for costly or difficult-to-install shadow shields.
Implementation Method 1
a fluid that attenuates neutron and gamma rays emitted from a fuel assembly
Implementation Method 2
a hollow flexible outer bladder... that accommodates varying gap sizes with no loss of shielding capability
Data Source
AI summary
An expansion gap radiation shield is formed from a flexible container housing a radiation shielding fluid, that is located within a variable gap in permanent shielding. The invention reduces radiation dose rates outside the gap when the radiation sources are located on the opposite side of the gap. The device accommodates varying gap sizes with no loss of shielding capability.