DEVELOPMENT OF Mo-Tc DOMESTIC PRODUCTION WITH HIGH-DENSITY MoO3 PELLETS BY (n, ) REACTION

The renewed JMTR will be started from the later half of JFY2012, and it is expected to contribute to many fields. As one of effective uses of the JMTR, JAEA has a plan to produce Mo by (n, ) method ((n, γ)Mo production), a parent nuclide of Tc. Tc is most commonly used as a radiopharmaceutical in the field of nuclear medicine. In case of Japan, the supply of Mo depends only on imports from foreign countries. Thus, the (n, γ)Mo production was adopted from viewpoints of safety, nuclear proliferation resistance and waste management in JMTR. The R&D has been carried out with foreign organizations and relevant Japanese manufacturers under the cooperation programs and original R&D promotion program in Japan. The main R&D items for the (n, γ)Mo production are as follows: (1) Fabrication development of irradiation target as the high-density MoO3 pellets, (2) Separation and concentration development of 99mTc by the solvent extraction from Mo solution, (3) Examination of 99mTc solution for a medicine, and (4) Mo recycling development from Mo generator and waste Mo solution. Molybdenum oxide (MoO3) is the most commonly used chemical form as irradiation target for the (n, γ)Mo production. The MoO3 pellet form with high density has been developed for large quantity (n, γ)Mo production and the preliminary fabrication tests of MoO3 pellets were carried out. The specific activity of (n, γ)Mo and subsequently the concentration of Tc in final product are very low. Therefore, methods of obtaining highly-concentrated Tc product should be developed and two methods have been proposed: one is based on solvent extraction as a Master-Milker and the other on using new adsorbents as Mo-Tc generator. It is important for domestic production to determine detail specifications of Tc solution and preliminary tests with practice solution using Re have been performed such as tests of radiochemical, radionuclidic, chemical purities, a biodistribution study, and apyrogenicity tests for medical use. Technology development for Mo recycling is required in order to establish cost-effective procedures because Mo enriched MoO3 is very expensive. The preliminary tests with PZC absorbed un-irradiated Mo were carried out. In this paper, the status of the R&D is described for the (n, γ)Mo production.