of support activities required both to provide raw fuel and to recover and recycle the uranium and plutonium make up — _ what is known as the nuclear fuel cycle. The AEC has projected that over 4 million megawatts of nuclear capacity will be installed between 1970 and 2020°, Over the lifetimes of these plants this installed capacity could result in a cumulative flow of approximately 200 million kilograms of plutonium through the nuclear fuel cycle. Ff In today's commercial reactors the plutonium is in oxide form, Pud,”. cycle, At various facilities in the nuclear fuel aerosols of Puld are released to the environment on a@ routine basis. In addition, there are numerous points in the fuel cycle where accidents, particularly those associated with’ fire or explosions, can release significant amounts of Puls as aerosols that can be inhaled by man. These small aerosol particles of Pu09 are highly radio+ active. An appreciable fraction of the inhaled Puld particles are trapped in the deep respiratory tissue of the lung, where, because they are insoluble in human tissue, ~ 4/ Updated (1970) Cost-Benefit Analvsis of the U. S. Breeder Reactor Procream, USAEC, WASH-1184, January 1972, p. Million megawatts 34. (Mw) corresponds to 4000 nominal-siz nuclear reactors -~ 1000 Mw each. S/ Some advanced reactors of the future may use fuel in Carbide and nitride, rather than oxide, forn. Four