Tc-99m is a very useful radioisotope in medical diagnostic procedures. Tc-99m is produced from Mo-99 decay. Global demand for Tc-99m is expected to grow at an average annual rate of 3 - 8 %. Therefore we need to increase the total production of Mo-99. Mo-99 is produced mainly by irradiating U-235 target fission in a nuclear reactor. Mo-99 is also created in the reactor fuel, but is not usually taken. Uranium enrichment dropping from 90% to 19.8% demands modifications on process operations to compensate for the resulting loss in output. The dropping of uranium enrichment is due to nuclear...