Transmutation in Reactor and Aqueous Corrosion Resistance of Technetium Metal

Abstract

In the context of the French nuclear waste management act of 1991, two options have been considered following enhanced reprocessing of spent fuel. The reference option is the transmutation by neutronic bombardment, the second option is to immobilize the separated radiotoxic elements in dedicated matrices ensuring long term stability. This paper summarizes the research and development activities carried out by CEA in France, concerning technetium. Nearly 90% of the technetium-99 present in spent fuel is separated in the UP2-800 reprocessing plant at La Hague, producing about 900 kg of Tc each year. The first part of the paper deals with the irradiation experiment ANTICORP 1 which aims at transmuting 99Tc under the form of metallic rods, in the core of the Phenix reactor. The goal of ANTICORP 1 is to achieve a transmutation rate of 99Tc in 100Ru greater than 20%. The main options chosen for the design and the safety study of the experiment are described. In addition, the planning of the irradiation and the post-irradiation exams foreseen, are detailed. The second part of the paper describes the studies carried out to investigate technetium metal as a potential containment matrix. The corrosion rate of this metal under water was measured over one year of alteration at 25 C