Homogenized Group Cross Sections for Individual Materials

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Mario I. Ortega
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Homogenized Group Cross Sections for Individual Materials

Post by Mario I. Ortega » Mon Jun 09, 2014 4:54 pm

Hello all,

I understand that Serpent2 has the ability to created group XS over universes but I was wondering if there was any way to obtain homogenized cross sections in individual materials? For example, I have an assembly with fuel, cladding, etc, and I was wondering if there might be a way to calculate 4-group cross sections for each of the materials in the assembly without homogenizing over the entire assembly or over the entire core later on. Let me know if this makes sense.

Mario

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Jaakko Leppänen
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Re: Homogenized Group Cross Sections for Individual Materials

Post by Jaakko Leppänen » Tue Jun 10, 2014 9:37 am

In any pin or cell structure you can replace material name "m1" with "fill u1", which means that the region is filled by universe "u1". If you then define this universe to consist of material "m1" and include all space:

Code: Select all

surf 1 inf
cell 1 u1 m1 -1
you can generate group constants for universe "u1" as if it was material "m1".

If you are interested only in reaction cross sections (have no use for scattering matrices, diffusion coefficients, etc.), it is probably easier to do this with detectors. In Serpent manual Sec. 7.1.1 there is an example of calculating microscopic fission and capture cross sections of U-235 and U-238 using detectors.
- Jaakko

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markdehart
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Re: Homogenized Group Cross Sections for Individual Materials

Post by markdehart » Thu Nov 13, 2014 2:11 am

Okay, here is a variation on the above. I'd like to get homogenized cross sections for m1 and m1 - I can do the above without a problem. What if I wanted to homogenize the remaining materials, m3, m4 and m5, to get a homogenization over the three materials combined. Is this possible?

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Jaakko Leppänen
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Re: Homogenized Group Cross Sections for Individual Materials

Post by Jaakko Leppänen » Thu Nov 13, 2014 3:37 am

If there's some way to tweak the geometry in such way that you have a universe that consists only of these three materials, then it should be possible to get the combined cross sections. What kind of materials are these?
- Jaakko

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markdehart
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Re: Homogenized Group Cross Sections for Individual Materials

Post by markdehart » Thu Nov 13, 2014 3:43 am

Yeah, I had thought about that - just wanted to avoid it. This is a TREAT model, and I am trying to homogenize the clad and air regions. I'll take a look and see how difficult that might be.

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