Plutonium as a Reactor Fuel
After successfully proving that plutonium could be produced in a breeder reactor, additional concepts were tested to facilitate the creation of commercial nuclear reactors. One of these was the use of plutonium as a reactor fuel. This was important to the designers and developers of EBR-I because, although U-238 could be mined in abundance, it was unsuitable for use in a reactor while scientists hypothesized that Pu-239, like U-235, could be used as a fuel. The EBR-I was the first reactor to use plutonium 239 and physically demonstrate this theory. While the new and larger EBR-II was being built, this small reactor continued to be used for various tests and in 1963 a plutonium core was in use as the EBR-I’s last fuel.
Walter Zinn proposed building a larger version of the reactor to both produce power