The Fission-Based？？99Mo Production Process ROMOL-99 and Its Application to PINSTECH Islamabad

An innovative process for fission based 99Mo production has been developed under Isotope Technologies Dresden (ITD) GmbH (former Hans W？lischmiller GmbH (HWM), Branch Office Dresden), and its functionality has been tested and proved at the Pakistan Institute of Nuclear Science and Technology (PINSTECH), Islamabad. Targets made from uranium aluminum alloy clad with aluminum were irradiated in the core of Pakistan Research Reactor-1 (PARR-1). In the mean time more than 50 batches of fission molybdenum-99 (99Mo) have been produced meeting the international purity/pharmacopoeia specifications using this ROMOL-99 process. The process is based on alkaline dissolution of the neutron irradiated targets in presence of NaNO3, chemically extracting the 99Mo from various fission products and purifying the product by column chromatography. This ROMOL-99 process will be described in some detail. 1. Introduction The present sources of molybdenum-99 (99Mo; ？h) are research reactors by neutron-induced fission of 235U, which results in high-specific activity 99Mo, or using the ( , ) nuclear reaction with 98Mo (natural Mo or enriched 98Mo = 24%), resulting in low-specific activity 99Mo. Generally, the specific activity of molybdenum produced by fission is more than 1000 times higher than that obtained by ( ) process. The almost universal means by which technetium-99m (99mTc; ？h) is made available for clinical applications is from the elution of generators containing high-specific activity fission-based 99Mo. The first chemical process for separation of fission 99Mo was described by the Brookhaven group, USA [1]. In this process the target (93% enriched U-235 alloyed with Al) was dissolved in 6？M nitric acid catalyzed by mercuric nitrate. In the former Zentralinstitut für Kernforschung (ZfK) Rossendorf, a fission-based 99Mo separation technology became operationally ready in 1963 which was actually the basis of the first fission-based 99Mo/99mTc generator in Europe. Metallic natural uranium pellets were used as target material and the dissolution of the irradiated U-pellets was done with concentrated HCl. Quartz and glass apparatus was used in chemical processing, and yield of 99Mo was ~70% [2]. In 1980, this process was replaced by the AMOR process (AMOR: Anlage zur Mo Production Rossendorf), developed in the same institute [3]. The AMOR process made use of original fuel elements of the RF-reactor as qualified target which was dissolved in HNO3/Hg. Batch-wise adsorption at Al2O3 and sublimation technique were used for separation and purification of the 99Mo. This process