David A. Rotsch

Fission Produced 99Mo without a Nuclear Reactor

99Mo, the parent of the widely used medical isotope 99mTc, is currently produced by irradiation of enriched uranium in nuclear reactors. The supply of this isotope is encumbered by the aging of these reactors and concerns about international transportation and nuclear proliferation. Methods: We report results for the production of 99Mo from the accelerator-driven subcritical fission of an aqueous solution containing low enriched uranium. The predominately fast neutrons generated by impinging high-energy electrons onto a tantalum convertor are moderated to thermal energies to increase fission processes. The separation, recovery, and purification of 99Mo were demonstrated using a recycled uranyl sulfate solution. Conclusion: The 99Mo yield and purity were found to be unaffected by reuse of the previously irradiated and processed uranyl sulfate solution. Results from a 51.8-GBq 99Mo production run are presented.

Optimization of the Processing of Mo Disks

The objective of this work is to decrease the processing time for irradiated disks of enriched Mo for the production of 99Mo. Results are given for the dissolution of nonirradiated Mo disks, optimization of the process for large-scale dissolution of sintered disks, optimization of the removal of the main side products (Zr and Nb) from dissolved targets, and dissolution of irradiated Mo disks.

SCALABILITY OF THE LEU-MODIFIED CINTICHEM PROCESS

Argonne National Laboratory with the National Nuclear Security Admiration’s (NNSA) Material Minimization and Management program (M 3 ), in partnership with SHINE Medical Technologies are developing technologies for the domestic production of 99 Mo. SHINE is planning to produce 99 Mo by fission of low enriched uranium (LEU) in a subcritical aqueous solution using an accelerator-based neutron generation. In support of this goal, irradiations at Argonne’s Van-de-Graaff facility simulating LINAC irradiations were performed. The LEU-Modified Cintichem process has been chosen by SHINE to process their irradiated solutions. However, Cintichem rarely processed more than 1000 Ci of 99 Mo in a single batch. A concern is the Mo-ABO complex will break down under high dose conditions, causing a decrease in the recovery of 99 Mo. Irradiations of the MoABO solid have been performed and the results will be discussed.