DESIGN OF A SUBCRITICAL AQUEOUS TARGET SYSTEM FOR MEDICAL ISOTOPE PRODUCTION

Abstract

The United States consumes almost half of all medical isotopes produced worldwide, and relies on foreign sources for nearly its entire supply. These isotopes are produced in nuclear reactors which are very costly to construct. A domestic supply may be realized if research reactors at universities and national laboratories can be enhanced with isotope production capabilities. This re-search is dedicated to the design of an aqueous target system that can be appended to exiting re-search reactors for this purpose. The design aims to combine attributes of solid target irradiation by conventional reactors and in-solution production by aqueous homogeneous reactors in order to realize some of the benefits of each method. The benefits for the former include using existing reactors as the external neutron source hence reducing the investment capital significantly. The benefits for aqueous homogeneous reactors are numerous and include higher efficiency, substantial reduction in waste, lower fuel cost, and reduced isotope separation complexity. Utilizing a flowing fuel design will enable continuous isotope separation and more efficient heat removal, as well as eliminate some of the complications that have plagued solution fueled reactors in the past such as power oscillations and fuel precipitation. The aqueous target system described in this thesis is designed for the Annular Core Research Reactor (ACRR) at Sandia National Laboratories. The system is optimized for 99Mo production, as this is the medical isotope in highest demand and used in a majority of all medical diagnostic procedures excluding x-ray imaging. The optimized production rate is calculated to be 3044 Ci6-day per week which accounts for 50.7% of domestic consumption.