Prompt Gamma Emission Surface Defect Detection
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Solution Overview
Problem
Standard nondestructive examination techniques are ineffective for assessing the structural integrity of radioactive components and containers in high radiation fields due to equipment access and operability issues.
Innovation Solution
A method involving a liquid crack penetrant with high nitrogen content or isotopes like Scandium, Vanadium, Manganese, or Titanium, combined with a neutron pulse generator and silicon carbide beta radiation detectors, to nondestructively detect structural defects by mapping prompt gamma releases from the surface, utilizing a novel combination of dye-penetrant detection and computerized tomography techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard visual and ultrasonic NDE techniques are used to assess structural integrity, then equipment access and operability are maintained, but detection accuracy fails in high radiation fields
Solution Approach 1:
The patent replaces mechanical NDE equipment (ultrasonic sensors, visual inspection tools) with a nuclear physics-based detection system. A neutron pulse generator emits neutrons that interact with nitrogen in crack penetrant to produce prompt gamma rays, which are detected by beta radiation detectors. This substitution eliminates the need for mechanical equipment access while maintaining reliable structural integrity assessment in high radiation fields.
Solution Approach 2:
The patent changes the detection parameter from mechanical wave propagation (ultrasonic) or optical reflection (visual) to nuclear reaction products (prompt gamma rays). By measuring the energy and intensity of gamma rays produced when neutrons interact with nitrogen in cracks, the system achieves reliable defect detection without requiring physical equipment access to the irradiated component surfaces.
2Measurement precision
If neutron pulse generator with crack penetrant is used for defect detection, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The patent applies crack penetrant containing nitrogen to the component surface before neutron irradiation. This preliminary action ensures that nitrogen is already present in crack openings, so when the neutron pulse generator irradiates the surface, prompt gamma rays are immediately produced at defect locations. This pre-positioning of the detection target simplifies the overall system by eliminating the need for complex real-time delivery mechanisms.
Solution Approach 2:
The patent uses nitrogen in the crack penetrant as an intermediary substance. The nitrogen acts as a mediator between the neutron pulse generator and the defect detection system. When neutrons interact with nitrogen in cracks, they produce prompt gamma rays that carry defect location information to the beta radiation detectors, simplifying the detection mechanism while maintaining high precision.
3Measurement precision
If liquid crack penetrant is applied to surface, then defect visibility is enhanced, but surface contamination increases
Solution Approach 1:
The patent utilizes the liquid-to-absorbed phase transition of the crack penetrant. The liquid penetrant is applied to the surface and then absorbed into crack openings through capillary action. This phase transition allows the penetrant to remain on the surface temporarily for detection purposes while eventually being absorbed, minimizing long-term contamination while maintaining defect visibility during the measurement process.
Solution Approach 2:
The patent employs crack penetrant that provides optical contrast (color changes) to enhance defect visibility. The penetrant contains chemicals that produce visible coloration in crack openings, allowing defects to be clearly distinguished from the surrounding surface. This visual enhancement works in conjunction with the neutron-gamma detection method to provide both optical and nuclear-based defect identification.
Data Source
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AI summary
A method of determining structural defects in a component that utilizes neutron activation of a solution having the ability to penetrate small cracks on the surface of a material via capillary absorption that produces a discernable prompt gamma release of a defined energy when exposed to a neutron pulse. The intensity of the gamma rays produced at the desired energy at a user controlled position on the surface is used to determine the crack location, length and depth.