136 



posed to the fission reaction, the higher the proportion of plutonium- 

 240 (Pu-240). The more Pu-240 is present, the less usetul the ma- 

 terial is for weapons because it makes the behavior of the material less 

 controllable. On the other hand, limiting the exposure of uranium 

 fuel in a power reactor limits the amount of plutonium-240 and makes 

 the recovered material more suitable for weapons. 



When nuclear power reactors are operated to produce the cheapest 

 electricity, the plutonium they produce as a by-product is not suitable 

 for very efficient nuclear weapons because of the Pu-240 present. 

 "Weapon grade" plutonium should contain no more than 10 percent 

 of these non-fissionable isotopes and preferably less. 7 



One way in which nuclear power reactors could be used to produce 

 weapons grade plutonium would be to limit the time the fuel spends 

 in the reactor to a few weeks, which is about a tenth of the normal 

 exposure time for economic nuclear power. However, even though con- 

 taminated with up to 30 percent of plutonium-240, the by-product 

 plutonium normally produced in present nuclear power reactors would 

 still be usable as the explosive material for primitive but still effective 

 nuclear weapons. 8 



When the breeder reactors favored by the United States are commer- 

 cially deployed during the 1980's, they will produce more plutonium 

 than the nuclear fuel they consume. Use of this technology will allow 

 many more nations to become self-sufficient in the production of nu- 

 clear fuel. Any nation with sufficient deposits of natural uranium can 

 then achieve a nuclear fuel cycle independent of other nations provided 

 it has enough enriched uranium or plutonium to start the cycle. From 

 the point of view of preventing proliferation of nuclear weapons, it 

 should be noted that the preferable fuel for fast-breeders will be the 

 same as that for efficient nuclear weapons, namely, plutonium con- 

 taining little of the isotope plutonium-240. The problem of preventing 

 the diversion of fissionable material seems likely to become more dif- 

 ficult as fast-breeder reactors come into widespread commercial use. 9 



Commercial Nuclear Power 



The large-scale generation of electricity from steam-electric power 

 plants requires access to an industrial base that can supply the furnaces, 

 boilers, turbines, generators, switchgear, and other electrical apparatus. 

 Additionally, it requires access to transportation facilities to move 

 huge amounts of fossil fuels — coal, oil, and natural gas. To introduce 

 commercial nuclear power requires access to industries that can design, 

 manufacture, install, and service the components of nuclear power 

 reactors, fabricate and reprocess uranium fuels, and indefinitely store 

 the residual radioactive wastes. Of these industrial capabilities, prob- 

 ably the most unusual are those for enriching uranium and for reproc- 

 essing used nuclear fuels. The other facilities are not greatly different 

 from those to be found in an industrialized country. 



The enrichment plants that have been built to date by the United 

 States and the Soviet Union are verv large industrial installations 



i Stockho'm International Pence Research Institute. World Armaments and Disarma- 

 ment: 8IPR1 Yearbook t:>: l (New fork: Humanities Press, 1972), p. 366. 

 - Loc, -it. 

 ll.i.l . p. 290. 



