What was the first of these types in which was supervised by Walter Zinn of the Manhattan Project?
Walter Zinn:  He worked at the Manhattan Project's Metallurgical Laboratory during World War II, and supervised the construction of Chicago Pile-1, the world’s first nuclear reactor, which went critical on December 2, 1942, at the University of Chicago. Chicago Pile-1: Chicago Pile-1 (CP-1), was the world's first artificial nuclear reactor.
i don't know