Magnetic Target Retrieval in Nuclear Reactor Instrumentation Tubes
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Solution Overview
Problem
Commercial nuclear reactors face inefficiencies in producing radionuclides due to non-homogeneous neutron flux density and the need for precise target positioning to avoid waste and ensure complete activation, leading to increased costs and safety hazards from incompletely activated targets.
Innovation Solution
A method utilizing dummy targets with different magnetic properties to optimize positioning and separation of irradiation targets within instrumentation tubes, ensuring complete activation by positioning them in areas with sufficient neutron flux, and using magnetic fields for efficient retrieval and storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If spherical irradiation targets are inserted into instrumentation tubes for radionuclide production, then alternative production sites are created and existing reactor infrastructure is utilized, but the non-homogeneous neutron flux density in the reactor core causes incomplete activation of targets positioned in low-flux areas, leading to waste and safety hazards
Solution Approach 1:
A magnetic retention assembly acts as an intermediary mechanism between the instrumentation tube and the irradiation target. This assembly uses magnetic fields to precisely hold the target at optimal positions within the neutron flux, ensuring complete activation while utilizing existing reactor infrastructure.
Solution Approach 2:
The system changes the positional parameters of irradiation targets within the instrumentation tube by using a magnetic retention assembly to adjust and maintain targets at specific locations where neutron flux density is sufficient for complete activation.
2Manufacturing precision
If a driving gear system is used to move and hold irradiation targets in instrumentation tubes, then precise positioning is achieved, but the device complexity increases and the system becomes more difficult to operate
Solution Approach 1:
The patent replaces complex mechanical driving gear systems with a magnetic field-based retention assembly. The magnetic assembly uses electromagnetic or permanent magnets to hold and position irradiation targets, eliminating the need for mechanical gears, motors, and associated control mechanisms.
Solution Approach 2:
The magnetic retention assembly serves as a simplified intermediary that provides precise positioning through magnetic forces rather than mechanical transmission, reducing system complexity while maintaining positioning accuracy.
3Strength
If pressurized gas is used to drive irradiation targets into and out from instrumentation tubes, then the system can handle mechanical loads, but the targets must be made from expensive high isotope purity parent material to withstand the mechanical and radiation conditions
Solution Approach 1:
The magnetic retention assembly acts as a protective intermediary that holds targets gently using magnetic forces, eliminating the need for high-velocity pneumatic insertion and extraction. This allows the use of less expensive target materials that would be damaged by high-speed gas-driven insertion.
Solution Approach 2:
The system performs preliminary positioning and holding of targets using magnetic fields before irradiation begins, ensuring targets are securely in place without requiring them to withstand high mechanical stresses during insertion and extraction.
4Reliability
If irradiation targets are positioned in areas with insufficient neutron flux to avoid waste, then activation efficiency is reduced, but positioning targets in high-flux areas ensures complete activation and eliminates waste from incomplete activation
Solution Approach 1:
The magnetic retention assembly enables precise control of target position parameters within the instrumentation tube, allowing targets to be placed exactly at the optimal location where neutron flux density ensures complete activation while maximizing production efficiency.
Data Source
AI summary
A method of producing radionuclides from irradiation targets in a nuclear reactor uses at least one instrumentation tube system of a commercial nuclear reactor. Irradiation targets and dummy targets are inserted into an instrumentation finger and the irradiation targets are activated by exposing them to neutron flux in the nuclear reactor core to form a radionuclide. The dummy targets hold the irradiation targets at a predetermined axial position in the reactor core corresponding to a pre-calculated neutron flux density sufficient for converting the irradiation targets to the radionuclide. Separating the dummy targets from the activated irradiation targets includes exposure to a magnetic field to retain either the dummy targets or the activated irradiation targets in the instrumentation tube system and release the other one of the activated irradiation target or the dummy target from the instrumentation tube system. An apparatus adapted to the above method is also provided.