The effects of polarization of deuterium and tritium nuclei in tokamaks are studied. Two cases are analysed: either both nuclei have spins aligned along the magnetic field, or deuterium only is polarized perpendicular to B. The number of the confined alpha particles is calculated and found to be nearly the same in both cases. However, for perpendicular spins, the total wall loading due to the fast-alpha losses decreases by a factor of about two, and the inner-wall and blanket loading due to the fast neutrons is also reduced.