The application of a symbiosis between light water reactors (LWRs) and 235U-Pu advanced pressurized water reactors (APWRs) has been found to have certain positive features as a strategy interim to the introduction of fast breeders and Pu-Udepl APWRs. On the basis of a particular model for the two-component system, it has been quantitatively shown how, as a result of the lower Pufiss inventory of the 235U-Pu APWR as well as its self-sufficiency in plutonium, the installed APWR capacity can grow faster than is the case for Pu-Udepl APWRs. The benefits, however, are to be realized at the expense of an increased absolute uranium ore consumption, since the 235U-Pu APWR does require a finite enriched-uranium feed. While, from the point of view of global energy policy, the fast breeder clearly holds the key to a nuclear generating capacity in the terawatt(electric) range, the present delays in its large-scale commercialization render it important to evaluate the pros and cons of alternative interim strategies. It is seen that such evaluations need to be made from the twin viewpoints of (a) improved uranium utilization, relative to standard L WRs, and (b) the quantities of effectively “stored” fissile plutonium.