In order to study the dynamic behaviours of three disintegration modes
(cold fission, alpha-decay and cluster radioactivities), we use a num
erical method based on the Euler-Lagrange's equation of motion to obta
in a constrained minimum of the WKB-integral in a tridimensional confi
guration space. The inertia is determined using the Werner-Wheeler app
roximation and the energy is computed in agreement with the Yukawa-plu
s-exponential model extended for binary systems with different charge
densities. The degrees of freedom of the system are: elongation, necki
ng-in and mass-asymmetry. Least-action trajectories are found for thre
e decay-modes of Pu-238.