Spherical Iridium Targets for Uniform NDT Radiation Sources
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Solution Overview
Problem
Conventional radiation sources for nondestructive inspection exhibit anisotropy, nonuniform target-by-target source strength, low geometric resolution, and lack of recyclability due to disc-like targets, making it difficult to achieve high-resolution images and efficient resource use.
Innovation Solution
Manufacturing a radiation source with small spherical irradiation targets made of iridium metal, which are accommodated in a rotating capsule and rotated by the downward flow of reactor primary coolant, eliminating anisotropy and ensuring uniform source strength and recyclability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If disc-like targets are stacked to form a cylindrical radiation source, then the source can be manufactured with conventional methods, but the radiation emitted is anisotropic and geometric resolution is low
Solution Approach 1:
The patent applies spheroidality by changing the target shape from disc-like (flat, cylindrical) to spherical. The spherical shape eliminates the anisotropic radiation pattern inherent in disc-like targets and improves geometric resolution. The sphere is formed by dropping molten iridium into a liquid medium, creating a spherical target that radiates uniformly in all directions.
Solution Approach 2:
The patent transitions from a two-dimensional disc-like target (with thickness and diameter) to a three-dimensional spherical target. This dimensional change allows the target to be rotated during irradiation, ensuring uniform exposure from all directions and eliminating the directional bias (anisotropy) present in cylindrical sources.
2Ease of manufacture
If disc-like targets are used, then manufacturing is straightforward, but target-by-target source strength is nonuniform and recyclability is difficult
Solution Approach 1:
The spherical shape ensures uniform source strength by providing consistent geometry and surface area across all targets. When molten iridium is dropped into a liquid medium, surface tension naturally forms a perfect sphere, eliminating variations in shape that would cause source strength nonuniformity. This geometric consistency enables reliable and uniform radiation output across all spherical targets.
Solution Approach 2:
The patent enables target recyclability by using spherical targets that can be uniformly irradiated and then rotated during use. After irradiation, the spherical targets can be recovered, re-irradiated, and reused with consistent performance. The uniform geometry and controlled irradiation process ensure that recycled targets maintain reliable source strength.
3Manufacturing precision
If a rotating capsule is used to rotate the target, then uniform irradiation can be achieved, but external power supply is required
Solution Approach 1:
The patent applies self-service by using the reactor's own primary coolant flow to rotate the capsule. The downward flow of coolant through the reactor core naturally drives the capsule rotation without requiring external motors or power supplies. This self-powered rotation mechanism eliminates complex electrical connections and power supply requirements while achieving uniform irradiation.
Solution Approach 2:
The patent uses hydraulic principles by utilizing the flow of reactor primary coolant to drive the rotation mechanism. The coolant flow, which is already present in the reactor for cooling purposes, is converted into a rotational driving force that uniformly irradiates the spherical target from all directions without requiring external mechanical or electrical 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 spherical targets enhance geometric resolution, reduce source strength variations, and improve recyclability, leading to cost-effective and efficient production of uniform radiation sources without the need for external power for rotation.
Implementation Method 1
rotating an axial flow impeller by a downward flow of a reactor primary coolant, whereby the rotating capsule is rotated
Implementation Method 2
The spherical irradiation target can be manufactured by dropping molten iridium into a liquid
Data Source
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AI summary
An irradiation target is formed into a sphere. The spherical irradiation target can be iridium metal (10) containing natural or enriched iridium 191. The radiation source of the present invention can be manufactured by manufacturing a spherical irradiation target, accommodating the spherical irradiation target in a rotating capsule (20), and rotating an axial flow impeller (32) by a downward flow of a reactor primary coolant, whereby the rotating capsule (20) is rotated. This radiation source provides an improved nondestructive inspection image having a high geometric resolution, and has no radiation source anisotropy and also has high target recyclability.