Which has the smaller critical mass; U-235 that releases 2.5 neutrons per fission, or Pu-239 that releases 2.7 neutrons per fission?
A)U-235
B)Pu-239
C)both would have the same critical mass.

Question

Quizplus · Accepted Answer

The critical mass is the minimum amount of fissile material required to sustain a nuclear chain reaction. The number of neutrons released per fission is an important factor in determining the critical mass. The more neutrons released per fission, the smaller the critical mass required. Pu-239 releases 2.7 neutrons per fission, which is higher than U-235's 2.5 neutrons per fission. Therefore, Pu-239 would have a smaller critical mass than U-235.

Which Has the Smaller Critical Mass; U-235 That Releases 2