Analysis of 99Mo Production Capacity in Uranyl Nitrate Aqueous Homogeneous Reactor using ORIGEN and MCNP

Abstract

^99mTc is a very useful radioisotope in medical diagnostic procedure. ^99mTc is produced from ⁹⁹Mo decay. Currently, most of ⁹⁹Mo is produced by irradiating ²³⁵U in the nuclear reactor. ⁹⁹Mo mostly results from the fission reaction of  ²³⁵U targets with a fission yield about 6.1%. A small additional amount is created from ⁹⁸Mo neutron activation. Actually ⁹⁹Mo is also created in the reactor fuel, but usually we do not extract it. The fuel will become spent fuel which is a highly radioactive waste. ⁹⁹Mo production system in the aqueous homogeneous reactor offers a better method, because all of the ⁹⁹Mo can be extracted from the fuel solution. Fresh reactor fuel solution consists of uranyl nitrate dissolved in water. There is no separation of target and fuel in an aqueous homogeneous reactor where target and fuel become one liquid solution, and there is no spent fuel generated from this reactor. Simulation of the extraction process is performed while reactor in operation (without reactor shutdown). With an extraction flow rate of 3.6 L/h, after 43 hours of reactor operation the production of ⁹⁹Mo is relatively constant at about 98.6 curie/hour./hour.

Received: 11 January 2014; Revised: 18 February 2014; Accepted: 28 February 2014