¹⁷⁷Lu Accumulation Parameters in Different Nuclear Reactors

A computational study of ¹⁷⁷Lu production in the neutron spectra of 26 nuclear research reactors was performed by two methods: from ¹⁷⁶Lu and ¹⁷⁶Yb. It is shown that the production of ¹⁷⁷Lu from ¹⁷⁶Lu with satisfactory specific activity ~7.4·10⁵ GBq/g and higher can be accomplished only in reactors with thermal neutron flux density not less than 10¹⁴ sec^–1·cm^–2. Under long-duration irradiation, not only is the specific activity of the desired isotope reduced but the contribution of ^177mLu in the activity increases, as a result of which the quality of the final product is lowered. The accumulation of ¹⁷⁷Lu from ¹⁷⁶Yb makes it possible to obtain high specific activity in all research reactors and requires using targets with high enrichment with ¹⁷⁶Yb and minimum content of ¹⁷⁴Yb. In addition, most importantly, the specific activity decreases under irradiation in reactors with high thermal neutron flux density, first and foremost, in SM and HFIR research reactors.