Resonance Self Shielding Correction Definition

[terryphi]

Hello,

I was hoping that someone might be able to provide a definition for the "resonance self shielding correction".

-TP

 

[QuantumPion]

In a homogenous reactor (e.g. liquid fuel mixed with moderator), the neutron flux is relatively constant because there is a equal distribution of fuel and moderator particles. When you have a heterogeneous reactor (e.g. solid fuel pins surrounded by water), neutrons have a higher chance of slowing down without being resonance absorbed because they can bounce around in the moderator without worrying about hitting a fuel atom while in the resonance range. The fuel shields itself from the neutron flux due to its resonance absorption cross section and therefore there is a relatively lower neutron flux in the fuel pins compared to the moderator.

The self-shielding correction factor is the degree of this effect, which mainly depends on the geometry and composition of the reactor.

 

[Astronuc]

I believe it refers to the high cross-section resonances shielding themselves and other resonances. The self-shielding is the same concept more or less.

 

[terryphi]

I've actually heard both definitions, so I'm confused.