Two successive long-duration experiments for the observation of deuteron-deuteron (d-d) fusion neutrons emanating from a massive palladium slab are described. The experimental effects observed are discussed through the use of a simple plasmalike model for the time dependence of fusion reactions in condensed matter, which is modified for a plane geometry. This results in a plasma fusion rate of . While plasmalike behavior leading to observable d-d fusion reaction intensities occurs temporarily, under nonequilibrium conditions of electrolytic charging only, for permanently occurring d-d molecular fusion in the fully loaded palladium slab from the experiments, only an upper limit can be set, which is given by Λd-d < 10-26 s-1.