Production of Mo-99 in research reactors with the use of uranium target and Mo-99 target

Modes of short-lived Mo-99 production for isotopic generators by irradiation of molybdenum target and from fission products of a special uranium target are analysed in the report. Specific activity of the Mo-99 in various irradiation modes is calculated. At neutron flux density 1014 cm-2s-1, 100% enrichment of a target with Mo-98, and average chord of a target of 5 mm, the specific activity 5.5 Curie/gram is reached. This value is quite acceptable to work isotopic generator. Thus, it is possible to produce Mo-99 from the molybdenum target if there is the reactor with thermal spectrum and rather high neutron flux. It is necessary to use highly enriched Mo-98 and target ensuring low blocking for resonant neutrons. It is important that in Mo-99 production from Mo-98 in thermal reactor, the high -active impurity is not produced. The activity of impurity can be reduced by application of highly enriched Mo-98. In production of Mo-99 from fission products, the specific activity varies over a wide range with change of enrichment of a uranium target. This permits to ensure required total activity of Mo-99 in target by choice a weight of target and enrichment of uranium depending on neutron flux density. With irradiation during 6 days, the specific activity of Mo-99 is equal to 71 kilocurie per 1 gram of all molybdenum isotopes. This is several orders higher than in production from molybdenum target. Thus, Mo-99 from fission products can be produced in reactor with low neutron flux: however this process requires more complex radiochemical processing and is possible if there is radiochemical productions