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.

 

[alphy]

Hello TP,

The resonance self shielding correction is a method used in nuclear physics to account for the effects of resonance absorption on neutron flux measurements. When neutrons are absorbed by a nucleus, they can cause the nucleus to vibrate or resonate, leading to a decrease in the number of neutrons available for further interactions. This effect is known as resonance self shielding. To correct for this, scientists use a mathematical correction factor that takes into account the energy of the neutrons and the properties of the material being measured. This correction is important in accurately measuring neutron flux levels in nuclear reactors and other nuclear systems. I hope this helps clarify the concept for you.