TRANSMUTATION OF TECHNETIUM - RESULTS OF THE EFTTRA-T1 EXPERIMENT

The transmutation of the fission product Tc-99 was studied by neutron irradiation in the High Flux Reactor at Petten. Six metallic rods of p ure Tc, distributed over three capsules, were irradiated during eight reactor cycles to a total neutron fluence of about 2 x 10(26) m(-2). M etallographic examinations showed that no changes in the microstructur e were visible after the irradiation. Electron probe microanalysis (EP MA) of the radial distribution of Ru, the product of the transmutation process, showed an increase from about 6% in the centre to 12-18% nea r the rim of the pellets. This effect is due to resonance-shielding of epithermal neutrons in the rim region. Mass spectrometric analysis of the pellet-average Ru concentration showed that the extent of transmu tation is about 6-7%. (C) 1998 Elsevier Science B.V.