Production Cycle for Large Scale Fission Mo-99 Separation by the Processing of Irradiated LEU Uranium Silicide Fuel Element Targets

Abdel-Hadi Ali Sameh

doi:10.1155/2013/704846

Abstract

Uranium silicide fuels proved over decades their exceptional qualification for the operation of higher flux material testing reactors with LEU elements. The application of such fuels as target materials, particularly for the large scale fission Mo-99 producers, offers an efficient and economical solution for the related facilities. The realization of such aim demands the introduction of a suitable dissolution process for the applied U3Si2compound. Excellent results are achieved by the oxidizing dissolution of the fuel meat in hydrofluoric acid at room temperature. The resulting solution is directly behind added to an over stoichiometric amount of potassium hydroxide solution. Uranium and the bulk of fission products are precipitated together with the transuranium compounds. The filtrate contains the molybdenum and the soluble fission product species. It is further treated similar to the in-full scale proven process. The generated off gas stream is handled also as experienced before after passing through KOH washing solution. The generated alkaline fluoride containing waste solution is noncorrosive. Nevertheless fluoride can be selectively bonded as in soluble CaF2by addition of a mixture of solid calcium hydroxide calcium carbonate to the sand cement mixture used for waste solidification. The generated elevated amounts of LEU remnants can be recycled and retargeted. The related technology permits the minimization of the generated fuel waste, saving environment, and improving processing economy.

Highlights

For the large scale producers, the conversion of the production targets for fission Mo-99 presents a serious challenge for keeping economical conditions for operating their plants
Uranium silicide fuels proved over decades their exceptional qualification for the operation of higher flux material testing reactors with low enriched uranium (LEU) elements
The idea of maintaining the current production process [1,2,3,4,5,6,7,8] by increasing fuel densities of the targets exploiting the progress in target technology from ∼1 gU/cm3 for highly enriched uranium (HEU) to approximately 2.6 gU/cm3 for low enriched uranium (LEU) targets can be classified as a compromise

Summary

Introduction

For the large scale producers, the conversion of the production targets for fission Mo-99 presents a serious challenge for keeping economical conditions for operating their plants. The idea of maintaining the current production process [1,2,3,4,5,6,7,8] by increasing fuel densities of the targets exploiting the progress in target technology from ∼1 gU/cm for highly enriched uranium (HEU) to approximately 2.6 gU/cm for low enriched uranium (LEU) targets can be classified as a compromise Such compromise is appropriate for several small- and medium-scale facilities but not for large scale producers of batch sizes in the average of 4000 Ci of Mo-99 at End of Production (EOP). Already during the development and testing at KFK, implementation of the silicide fuel and related modifications of the original (UAlx) process had to fit to the proven process concept. The remaining silicide residue is dissolved in hydrofluoric acid under oxidizing conditions [22, 23]

Considerations on Processing Operation

40 Bio-Rex5

Findings

Conclusions