Method for Fabricating .sup. 99 Mo Production Targets Using Low Enriched Uranium, .sup. 99 Mo Production Targets Comprising Low Enriched Uranium
Method for Fabricating .sup. 99 Mo Production Targets Using Low Enriched Uranium, .sup. 99 Mo Production Targets Comprising Low Enriched Uranium

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Published: 1997

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A radioisotope production target and a method for fabricating a radioisotope production target is provided, wherein the target comprises an inner cylinder, a foil of fissionable material circumferentially contacting the outer surface of the inner cylinder, and an outer hollow cylinder adapted to receive the substantially foil-covered inner cylinder and compress tightly against the foil to provide good mechanical contact therewith. The method for fabricating a primary target for the production of fission products comprises preparing a first substrate to receive a foil of fissionable material so as to allow for later removal of the foil from the first substrate, preparing a second substrate to receive the foil so as to allow for later removal of the foil from the second substrate; attaching the first substrate to the second substrate such that the foil is sandwiched between the first substrate and second substrate to prevent foil exposure to ambient atmosphere, and compressing the exposed surfaces of the first and second substrate to assure snug mechanical contact between the foil, the first substrate and the second substrate.

Method for Fabricating 99Mo Production Targets Using Low Enriched Uranium, 99Mo Production Targets Comprising Low Enriched Uranium
Method for Fabricating 99Mo Production Targets Using Low Enriched Uranium, 99Mo Production Targets Comprising Low Enriched Uranium

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Published: 1993

Total Pages: 15

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A radioisotope production target and a method for fabricating a radioisotope production target is provided, wherein the target comprises an inner cylinder, a foil of fissionable material (low enriched U) circumferentially contacting the outer surface of the inner cylinder, and an outer hollow cylinder adapted to receive the substantially foil-covered inner cylinder and compress tightly against the foil to provide good mechanical contact therewith. The method for fabricating a primary target for the production of fission products comprises preparing a first substrate to receive a foil of fissionable material so as to allow for later removal of the foil from the first substrate, preparing a second substrate to receive the foil so as to allow for later removal of the foil from the second substrate; attaching the first substrate to the second substrate such that the foil is sandwiched between the first substrate and second substrate to prevent foil exposure to ambient atmosphere, and compressing the exposed surfaces of the first and second substrate to assure snug mechanical contact between the foil, the first substrate and the second substrate.

Continuing Investigations for Technology Assessment of 99Mo Production from LEU (low Enriched Uranium) Targets
Continuing Investigations for Technology Assessment of 99Mo Production from LEU (low Enriched Uranium) Targets

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Published: 1987

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Currently much of the world's supply of /sup 99m/Tc for medical purposes is produced from 99Mo derived from the fissioning of high enriched uranium (HEU). The need for /sup 99m/Tc is continuing to grow, especially in developing countries, where needs and national priorities call for internal production of 99Mo. This paper presents the results of our continuing studies on the effects of substituting low enriched Uranium (LEU) for HEU in targets for the production of fission product 99Mo. Improvements in the electrodeposition of thin films of uranium metal are reported. These improvements continue to increase the appeal for the substitution of LEU metal for HEU oxide films in cylindrical targets. The process is effective for targets fabricated from stainless steel or hastaloy. A cost estimate for setting up the necessary equipment to electrodeposit uranium metal on cylindrical targets is reported. Further investigations on the effect of LEU substitution on processing of these targets are also reported. Substitution of uranium silicides for the uranium-aluminum alloy or uranium aluminide dispersed fuel used in other current target designs will allow the substitution of LEU for HEU in these targets with equivalent 99Mo-yield per target and no change in target geometries. However, this substitution will require modifications in current processing steps due to (1) the insolubility of uranium silicides in alkaline solutions and (2) the presence of significant quantities of silicate in solution. Results to date suggest that both concerns can be handled and that substitution of LEU for HEU can be achieved.

Development of Uranium Metal Targets for 99Mo Production
Development of Uranium Metal Targets for 99Mo Production

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Published: 1993

Total Pages: 10

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A substantial amount of high enriched uranium (HEU) is used for the production of medical-grade 99Mo. Promising methods of producing irradiation targets are being developed and may lead to the reduction or elimination of this HEU use. To substitute low enriched uranium (LEU) for HEU in the production of 99Mo, the target material may be changed to uranium metal foil. Methods of fabrication are being developed to simplify assembly and disassembly of the targets. Removal of the uranium foil after irradiation without dissolution of the cladding is a primary goal in order to reduce the amount of liquid radioactive waste material produced in the process. Proof-of-concept targets have been fabricated. Destructive testing indicates that acceptable contact between the uranium foil and the cladding can be achieved. Thermal annealing tests, which simulate the cladding/uranium diffusion conditions during irradiation, are underway. Plans are being made to irradiate test targets.

Processing of LEU Targets For[sup 99]Mo Production--testing and Modification of the Cintichem Process
Processing of LEU Targets For[sup 99]Mo Production--testing and Modification of the Cintichem Process

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Published: 2001

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Recent experimental results on testing and modification of the Cintichem process to allow substitution of low enriched uranium (LEU) for high enriched uranium (HEU) targets are presented in this report. The main focus is on[sup 99]Mo recovery and purification by its precipitation with[alpha]-benzoin oxime. Parameters that were studied include concentrations of nitric and sulfuric acids, partial neutralization of the acids, molybdenum and uranium concentrations, and the ratio of[alpha]-benzoin oxime to molybdenum. Decontamination factors for uranium, neptunium, and various fission products were measured. Experiments with tracer levels of irradiated LEU were conducted for testing the[sup 99]Mo recovery and purification during each step of the Cintichem process. Improving the process with additional processing steps was also attempted. The results indicate that the conversion of molybdenum chemical processing from HEU to LEU targets is possible.

Full-scale Demonstration of the Cintichem Process for the Production of Mo-99 Using a Low-enriched Target
Full-scale Demonstration of the Cintichem Process for the Production of Mo-99 Using a Low-enriched Target

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Published: 1998

Total Pages: 10

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The irradiation, disassembly, and processing of two full-scale low-enriched uranium (LEU) targets were recently demonstrated by personnel in the BATAN PUSPIPTEK Facilities (Serpong, Indonesia). Targets were fabricated at Argonne National Laboratory (Argonne, IL, U.S.A.) and shipped to PUSPIPTEK. The processing was done by nearly the same procedure used for the production of 99Mo from high-enriched uranium (HEU) targets. The BATAN Radioisotope Production Centre produces 99Mo using the Cintichem process by first dissolving the uranium in an acid cocktail; three proprietary separation steps recover the 99Mo and purify it from other components of the irradiated uranium. Processing of LEU-metal targets is nearly identical to that used for HEU-oxide targets except (1) a separate dissolver is required and (2) the dissolution cocktail is nitric acid alone rather than a nitric/sulfuric acid mixture. The demonstrations went smoothly except for problems with sampling and gamma analysis to assess product purity. Foils could be removed from targets fabricated from zirconium and/or 304 stainless steel, and processing produced an equivalent yield of 99Mo/235U to that of the HEU target.