In 1942, the world’s first nuclear fission reactor was built and operated by a team of physicists headed by Enrico Fermi under the bleachers of an abandoned stadium (Fig. P30.86) at the University of Chicago. The reactor was simply a pile of graphite bricks and uranium metal, measuring 20 ft high by 25 ft wide, with cadmium rods as a moderator. 

The reaction lasted 33 min and produced 0.5 W of power, confirming that a nuclear chain reaction had been achieved. 

(a) How much energy was released during this first fission reaction? 

(b) How many neutrons were produced and left the pile during the reaction?