MLA Citation: Bloomfield, Louis A. "Question 1280"
How Everything Works 18 Oct 2017. 18 Oct 2017 <>.
1280. Is critical mass the same for all fissionable materials? — JG, Bateman, Australia
Critical mass is something of a misnomer because in addition to mass, it also depends on shape, density, and even the objects surrounding the nuclear fuel. Anything that makes the nuclear fuel more efficient at using its neutrons to induce fissions helps that fuel approach critical mass. The characteristics of the materials also play a role. For example, fissioning plutonium 239 nuclei release more neutrons on average than fissioning uranium 235 nuclei. As a result, plutonium 239 is better at sustaining a chain reaction than uranium 235 and critical masses of plutonium 239 are typically smaller than for uranium 235.

Return to
Generated for printing on Wednesday, October 18, 2017 at 12:47:58 EDT
Copyright 1997-2017 © Louis A. Bloomfield, All Rights Reserved
Privacy Policy