The role of the breeder reactor

The proliferation hazards of the breeder reactor can best be restrained by delaying breeder deployment until it is economically advantageous. The breeder should be regarded as a means for converting a given investment of uranium ore into electrical energy. Because of the 0.7 per cent U-235 content of natural uranium, even a breeding gain of zero will allow a 1 000-MW(e) liquid metal-cooled fast breeder reactor (LMFBR) to be fuelled initially with 11 250 kg of U-235 as 20 per cent in U-238, and then to operate for 2000 years on the 3 100 short tons of U, 0₈ from which that U-235 was extracted. An assumed resource base of 3.5 million tons of U, O_g would thus start and operate 1 100 such simplified LMFBRs for 2 000 years, as compared with 500 light water reactors (LWRs) for only 30 years. Redesign of the LMFBR can reduce the $200 million initial penalty per reactor which would be incurred in this use of U-235 if LWR plutonium were available. If a molten salt breeder reactor is practical with a 2 500-kg U-235 inventory, some 5 000 could be started and operated for 500 years from the assumed resource base. After the exhaustion of low-cost uranium, a breeder population could be maintained (but not started) on uranium costing $5 000/lb without significant increase in electrical energy costs. Although plutonium will have to be recycled in plutonium breeders started with U-235 (and, to the extent it is available, should be used to fuel plutonium breeders), the route of U-235 investment will allow a large, rapid deployment of breeders when they are economically desirable without the necessity of premature commercial breeder operation or plutonium separation.