Weighted delayed neutron fraction?

[curie]

I am plotting the in-hour equation. For the delayed neutron fraction, I was thinking of using a weighted dnf for the particular U fuel enrichment of interest, ie combination of U235 & U238 dnfs, as I cannot look one up for this particular enrichment. Any comment on the “validity” or otherwise of this approach?

Btw, this is just for playing around with data & equations, not any kind of serious or real application. I am using dnf values from an old textbook which is adequate for my purposes but if you are aware of a reputable web resource for this kind of data I’d be grateful for a link.

Thanks for any input.

 

[Morbius]

I am plotting the in-hour equation. For the delayed neutron fraction, I was thinking of using a weighted dnf for the particular U fuel enrichment of interest, ie combination of U235 & U238 dnfs, as I cannot look one up for this particular enrichment. Any comment on the “validity” or otherwise of this approach?

Btw, this is just for playing around with data & equations, not any kind of serious or real application. I am using dnf values from an old textbook which is adequate for my purposes but if you are aware of a reputable web resource for this kind of data I’d be grateful for a link.

Thanks for any input.

curie,

You can use a weighted average of the delayed fraction.

Additionally, you have two isotopes of Uranium with similar delayed fractions.

The place where this would really come into play is when you have a mixture of
Uranium and Plutonium because the the delayed fraction for Plutonium is about a
1/3 of what it is for Uranium; 0.2% vs 0.7% if I recall.

Dr. Gregory Greenman
Physicist