Measuring α-emitters such as ( 2 3 4 , 2 3 5 , 2 3 6 , 2 3 8 U, 2 3 8 , 2 3 9 , 2 4 0 , 2 4 2 , 2 4 4 Pu, 2 3 7 Np, 2 4 1 , 2 4 3 Am, ...), in solid radioactive waste allows us to quantify the α-activity in a drum and then to classify it. The simultaneous photon and neutron interrogation experiment (SIMPHONIE) method dealt with in this paper, combines both active neutron interrogation and induced photofission interrogation techniques simultaneously. Its purpose is to quantify fissile ( 2 3 5 U, 2 3 9 , 2 4 1 Pu, ...) and non-fissile ( 2 3 6 , 2 3 8 U, 2 3 8 , 2 4 0 Pu, ...) elements separately in only one measurement. This paper presents the principle of the method, the experimental setup, and the first experimental results obtained using the DGA/ETCA Linac and MiniLinatron pulsed linear electron accelerators located at Arcueil, France. First studies were carried out with U and Pu bare samples.