Preliminary Investigations for Technology Assessment of 99Mo Production from LEU (low Enriched Uranium) Targets. [For Production of
Preliminary Investigations for Technology Assessment of 99Mo Production from LEU (low Enriched Uranium) Targets. [For Production of

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Published: 1986

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This paper presents the results of preliminary studies on the effects of substituting low enriched uranium (LEU) for highly enriched uranium (HEU) in targets for the production of fission product 99Mo. Issues that were addressed are: (1) purity and yield of the 99Mo//sup 99m/Tc product, (2) fabrication of LEU targets and related concerns, and (3) radioactive waste. Laboratory experimentation was part of the efforts for issues (1) and (2); thus far, radioactive waste disposal has only been addressed in a paper study. Although the reported results are still preliminary, there is reason to be optimistic about the feasibility of utilizing LEU targets for 99Mo production. 37 refs., 1 fig., 5 tabs.

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.

Low-enriched Uranium High-density Target Project. Compendium Report
Low-enriched Uranium High-density Target Project. Compendium Report

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Published: 2016

Total Pages: 675

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At present, most 99Mo is produced in research, test, or isotope production reactors by irradiation of highly enriched uranium targets. To achieve the denser form of uranium needed for switching from high to low enriched uranium (LEU), targets in the form of a metal foil (~125-150 μm thick) are being developed. The LEU High Density Target Project successfully demonstrated several iterations of an LEU-fission-based Mo-99 technology that has the potential to provide the world's supply of Mo-99, should major producers choose to utilize the technology. Over 50 annular high density targets have been successfully tested, and the assembly and disassembly of targets have been improved and optimized. Two target front-end processes (acidic and electrochemical) have been scaled up and demonstrated to allow for the high-density target technology to mate up to the existing producer technology for target processing. In the event that a new target processing line is started, the chemical processing of the targets is greatly simplified. Extensive modeling and safety analysis has been conducted, and the target has been qualified to be inserted into the High Flux Isotope Reactor, which is considered above and beyond the requirements for the typical use of this target due to high fluence and irradiation duration.

Development and Processing of LEU Targets for 99Mo Production-overview of the ANL Program
Development and Processing of LEU Targets for 99Mo Production-overview of the ANL Program

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Published: 1995

Total Pages: 10

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Most of the world's supply of {sup 99m}Tc for medical purposes is currently produced from the decay of 99Mo derived from the fissioning of high-enriched uranium (HEU). Substitution of low-enriched uranium (LEU) silicide fuel for the HEU alloy and aluminide fuels used in most current target designs will allow equivalent 99Mo yields with little change in target geometries. Substitution of uranium metal for uranium oxide films in other target designs will also allow the substitution of LEU for HEU. During 1995, we have continued to study the modification of current targets and processes to allow the conversion from HEU to LEU. A uranium-metal-foil target was fabricated at ANL and irradiated to prototypic burnup in the Indonesian RSG-GAS reactor. Postirradiation examination indicated that minor design modifications will be required to allow the irradiated foil to be removed for chemical processing. Means to dissolve and process LEU foil have been developed, and a mock LEU foil target was processed in Indonesia. We have also developed means to dissolve the LEU foil in alkaline peroxide, where it can be used to replace HEU targets that are currently dissolved in base before recovering and purifying the 99Mo. We have also continued work on the dissolution of U3Si2 and have a firm foundation on dissolving these targets in alkaline peroxide. The technology-exchange agreement with Indonesia is well underway, and we hope to expand our international cooperations in 1996.

Converting 99Mo Production from High- to Low-enriched Uranium
Converting 99Mo Production from High- to Low-enriched Uranium

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Published: 1997

Total Pages: 3

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This paper discusses efforts towards LEU substitution in two HEU targets. One type is the Cintichem target, a closed cylinder with a thin coating of uranium dioxide electroplated ion the inside wall. To successfully increase the amount of uranium per target, we are developing a target that uses LEU metal foil. Uranium surface preparation is discussed.

Processing of LEU Targets for 99Mo Production -- Dissolution of Metal Foils by Nitric-acid
Processing of LEU Targets for 99Mo Production -- Dissolution of Metal Foils by Nitric-acid

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Published: 1995

Total Pages: 17

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The first step in processing low-enriched uranium (LEU) targets for production of 99Mo is to dissolve the neutron-irradiated uranium foil coming from the reactor. Appropriate conditions for dissolving the foils were determined by measuring the dissolution rates for uranium foil over a wide range of temperatures and acid concentrations. On the basis of these dissolution rates, the process chemistry, and a model that integrates dissolution rates as a function of temperature and composition, a closed stainless-steel dissolver was designed, built, and tested for dissolving up to 18 g of uranium foil. The results were quite successful, with the uranium foil being dissolved within one hour as desired. To do this, the dissolver temperature must be in the range from 97 to 102 C, and the dissolver solution (cocktail) must have a composition of 3M nitric acid and 2M sulfuric acid. The final dissolver solution is subsequently processed to separate 99Mo from uranium, fission products, and other elements.

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.

Processing of LEU Targets for 99Mo Production--testing and Modification of the Cintichem Process
Processing of LEU Targets for 99Mo Production--testing and Modification of the Cintichem Process

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Published: 1995

Total Pages: 13

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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 99Mo 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 99Mo 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.