- #1

Andrej.N

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## Homework Statement

Uranium has two common isotopes with atomic masses of 238 and 235. One way to separate these isotopes is to combine the uranium with fluorine to make uranium hexafluoride gas, UF6, and then to let it effuse through a small hole. The natural abundance of the 235U isotope is 0.7%. Light‐water reactors, the world’s most common type of nuclear reactor, require a 235U abundance of approximately 4%. How many effusion stages are at least required to increase the 235U abundance to this level? The rate of effusion is proportional to v_rms.

## Homework Equations

I'm not sure how to approach this question since we haven't covered rates of effusion and I'm unfamiliar with the concept of effusions stage. What defines an effusion stage?

## The Attempt at a Solution

Following Schroder's book on Thermodynamics, the rate of effusion I assume reduces to [itex]v_{rms-238U F6}/v_{rms-235UF6}[/itex], which reduces to Graham's Law, which is: [itex]\sqrt {m_{(238)UF6}/m_{(235)UF6)}\approx1.0043[/itex]

From here I don't know how to proceed to get the minimal number of stages requiered.

Thanks in advance for your help.