The breeding capability of a fusion reactor for Pu-239 is analyzed to provide fissile fuel for LWRs as a prospective alternative in addition to existing methods of nuclear fuel enrichment, such as gas diffusion and gas centrifuge plants. The analysis is conducted for the catalyzed-(D,D) and (D,T) fusion reactors. Two different coolants (helium gas and Flibe "Li2BeF4") are selected for the nuclear heat transfer out of the fissile breeding zone fuelled with natural uranium. Depending on the type of fusion driver and coolant in the fission zone, power plant operation periods between 12 and 36 months are evaluated to achieve a fissile fuel enrichment quality between 3% and 4% under a first-wall fusion neutron energy load of 5 MW/m(2) and a plant factor of 75%. For unit fusion neutron energy flux on the first-wall, a catalyzed (D,D) fusion reactor can breed faster than a (D,T) reactor because the former is richer in neutrons than the latter. The Flibe coolant is superior to helium coolant with regard to fissile fuel breeding. During a plant operation over four years, enrichment grades between 4.4% and 8.9% are calculated. The denaturation of the plutonium fuel requires about 2 years of irradiation with fusion neutrons for all investigated cases. During this period, it is possible to breed a high quality, but denatured plutonium for light water reactors. This is an important factor with regard to international safeguarding. (C) 1998 Elsevier Science Ltd. All rights reserved.