Measurement of cumulative photofission yields of 235U and 238U with a 16 MeV Bremsstrahlung photon beam

In the frame of a long-term research program on characterization large radioactive waste packages by photofission, Nuclear Measurement Laboratory CEA IRESNE, France, has measured cumulative photofission yields 235U and 238U short-lived long-lived fission products using Bremsstrahlung photon beam produced 16 MeV electron linear accelerator (LINAC). To this aim, been carried out activation analysis with different samples gold, nickel, uranium zirconium. The residual neutron flux exiting LINAC head (lead collimator, borated polyethylene cadmium shield) also characterized indium to estimate contribution photoneutron fissions in used assess yields. Finally, 49 product are reported for 26 235U, half-lives ranging from 64 s more than 3 days, some them not recorded so far literature Some show significant differences between 238U, which confirms possibility an isotopic discrimination method based delayed gamma-ray ratios characterization.