REACTORES FÍSICA NUCLEAR INGENIERÍA NUCLEAR NUCLEAR ENGINEERING NUCLEAR PHYSICS REACTORS CALCULUS OF VARIATIONS CINÉTICA CINÉTICA DE LAS REACCIONES NUCLEARES CONFINAMIENTO DE PLASMA CONTROLLED FUSION FUSION REACTORS GASES IONIZADOS MÉTODOS VARIACIONALES NUCLEAR REACTIONS NUCLEAR REACTOR KINETICS NUCLEAR REACTORS PLASMA PLASMA (IONIZED GASES) PLASMA CONFINEMENT REACTORES TERMONUCLEARES