## Lattice power output

This category replaces the missing input manual
markdehart
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### Lattice power output

The Serpent 1 manual describes "Power distributions in lattices." However, in a sss2 calculation that included a lattice, I get no power output. Is this available in Serpent 2?

Jaakko Leppänen
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### Re: Lattice power output

The main reason for this capability in Serpent 1 is to do pin-power reconstruction. In Serpent 2, the calculation of pin-wise peaking factors is invoked using a new input card:

Code: Select all

``````set ppw <uni> <lat>
``````
where <uni> links the distribution to a universe where the power distribution is calculated and <lat> is the lattice where this calculation is performed. The results are printed in variable PPW_POW_FRAC, and they are the fractional power per pin and energy group over the lattice.

To get the results in human-readable form, I use the following matlab commands: (for 17x17 assembly, 2 energy groups)

Code: Select all

``````P = reshape(PPW_POW_FRAC(1:2:end),2,17,17);
P1 = reshape(P(1,:,:), 17,17);
P2 = reshape(P(2,:,:), 17,17);
``````
This gives two matrices, P1 and P2, which contain the distribution for fast and thermal group, respectively.

If your purpose for calculating power distribution in a lattice is not group constant generation, it's probably better to use detectors.
- Jaakko

bilodid
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### Re: Lattice power output

Are resulting matrices P1 and P2 normalised to the same value?
i.e. if I will summ them POW = P1 + P2 = relative pin power map?

Thanks!

xixipang
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### Re: Lattice power output

Hello,

I have this question on the power distribution. Since for a PWR e.g. we normally set a lattice for an assembly and a lattice for the whole core. So if the <lat> is set as the lattice for an assembly, which assembly in the core is taken for the calculation?

Thanks.

Jaakko Leppänen