Technical and economic studies on the startup of fast breeders with plutonium of $sup 235$U

The amounts of fissile materials in the form of /sup 239/Pu or /sup 235/ U necessary for the startup and transient regime of a fast breeder reactor are determined and compared with each other using an analytical model. With that, the most important physico-technical parameters of the reactor, in particular the different critical masses and breeding factors for the two different fissile materials, the operating characteristics of the reactor, and the parameters of the external fuel cycle are taken into consideration. The algorithm given enables a large number of survey calculations with relatively small effort and may serve for optimizing the parameters introduced into the calculations and for evaluating a system-related plutonium price on the basis of that of uranium. (4 references) (auth)