Transmutation studies using SSNTD and radiochemistry and the associated production of secondary neutrons

Experiments using 1.5 GeV, 3.7 GeV and 7.4 GeV protons from the Synchrophas otron, LHE, JINR, Dubna, Russia, on extended Pb- and U-targets were carried out using SSNTD and radiochemical sensors for the study of secondary neutr on fluences. We also carried out first transmutation studies oil the long-l ived radwaste nuclei I-129 and Np-237. In addition, we carried out computer code simulation studies on these syste ms using LAHET and DCM/CEM codes. We have difficulties to understand rather large transmutation rates observed experimentally when they are compared w ith computer simulations. There seems to be a rather fundamental problem un derstanding the large transmutation rates as observed experimentally in Dub na and CERN, as compared to those theoretical computer simulations mentione d above.