There are alternative routes for generating 99Mo that do not require a fissionable target, such as high or low enriched uranium (i.e., HEU or LEU).
Implementing feed-stocks of high specific activity 99Mo solutions thus allowed for higher quality production and better separations of 99mTc from 99Mo on small alumina column using chromatography.
Employing low-specific activity 99Mo under similar conditions is particularly problematic in that either higher Mo loading capacities or larger columns are required for accommodating equivalent amounts of 99Mo.
Chemically speaking, this phenomenon occurs due to other Mo isotopes present aside from 99Mo that compete for surface site interactions on the column substrate.
In the last decade, cooperative agreements between the US government and private capital entities have resurrected neutron capture production for commercially distributed 99Mo/99mTc in the United States of America.