Additive Uranium Target for Mo-99 Production
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Solution Overview
Problem
Current methods for producing molybdenum-99 using uranium targets in reactors face challenges such as inefficient use of reactor space, risk of fissile material scattering during processing and transportation, and suboptimal neutron beam energy utilization, leading to cumbersome and hazardous handling of radioactive materials.
Innovation Solution
A method involving the fabrication of a uranium target with a predetermined mass and volume using low-enriched uranium, created through an additive process like 3D printing with a selective laser, forming an openwork structure with an infill pattern that maximizes mechanical cohesion and minimizes scattering risks, while optimizing neutron absorption and gas flow for efficient irradiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If granulated uranium material is used in the target, then the target can be filled into the reactor chamber, but the material scatters during processing and transportation causing contamination risks
Solution Approach 1:
The patent uses a porous sintered uranium structure where uranium particles are bound together in a porous matrix. This maintains the uranium in a fixed solid form rather than loose granulated material, preventing scattering during handling while still allowing neutron penetration and heat transfer through the porous structure.
Solution Approach 2:
The target comprises a composite structure of uranium particles bound in a matrix material (such as metal or ceramic). This composite approach combines the fissile properties of uranium with the structural integrity and binding properties of the matrix, creating a mechanically stable target that resists scattering during processing and transportation.
2Reliability
If low-enriched uranium is used instead of highly-enriched uranium, then safety requirements are met, but irradiation efficiency is reduced
Solution Approach 1:
The patent optimizes physical parameters of the target structure including density, porosity, particle size distribution, and geometric configuration to maximize neutron utilization. By carefully controlling these parameters, the target achieves high irradiation efficiency with low-enriched uranium, compensating for the lower U-235 content through improved neutron economy and energy utilization.
Solution Approach 2:
The target employs non-uniform distribution of uranium material with varying local density and composition. Regions with higher uranium concentration are placed where neutron flux is highest, optimizing the fission reaction rate throughout the target volume and improving overall irradiation efficiency while maintaining safety compliance.
3Ease of manufacture
If universal target shapes are used, then manufacturing is simplified, but reactor space utilization is not optimized
Solution Approach 1:
The patent employs additive manufacturing (3D printing) technologies that enable rapid prototyping and customization of target geometries. This dynamic manufacturing approach allows targets to be precisely tailored to the specific dimensions and neutron flux distribution of different reactor chambers, optimizing space utilization while maintaining manufacturing feasibility through digital design and automated fabrication.
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
This approach allows for safer handling and more efficient production of molybdenum-99 by reducing the risk of contamination, improving reactor space utilization, and enhancing irradiation efficiency, thereby streamlining the production process and reducing the hazards associated with handling radioactive materials.
Implementation Method 1
selectively heating by means of a laser
Implementation Method 2
fabrication step, a target shaped so as to enable enclosing it in a container to be placed in a reactor is made of this construction material, the fabrication step being carried out in an additive process by applying successive layers of the construction material and selectively heating by means of a laser
Implementation Method 3
cooling is provided by forced circulation of gas
Implementation Method 4
irradiation of a uranium target in a reactor
Implementation Method 5
production of molybdenum from a material irradiated in a reactor
Data Source
Figure 1
Figure 2A~2C
Figure 3~4A
AI summary
A method of fabricating a target (200) with predetermined mass and volume from low-enriched uranium, in which the fabrication step (102) is carried out in an additive process by applying successive layers of the construction material and selectively heating by means of a laser, according to the invention is characterized in that prior to the fabrication of the target (200), a digital model of the target (200) with dimensions substantially matching the dimensions of the container is created, the model defining an openwork cohesive body filling the container with margins. A process of producing molybdenum 99 comprising a step of fabricating (102) a target (200) from a construction material containing low-enriched uranium, a step of packing (103) the target (200) into a container, a step of irradiating (104) by placing the container with the target (200) in a reactor followed by an unpacking step (105), a transport step (106), and a step of chemical treatment (107) of the target for obtaining molybdenum 99, according to the invention is characterized in that the step of fabricating (102) a target is performed using the method according to the invention. The invention concerns also the target (200) having an openwork structure with voids.