Lattice power output

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markdehart
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Lattice power output

Post by markdehart » Wed Jan 08, 2014 12:28 am

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?

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Jaakko Leppänen
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Re: Lattice power output

Post by Jaakko Leppänen » Wed Jan 08, 2014 9:58 am

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:

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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)

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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

Post by bilodid » Fri Oct 24, 2014 5:17 pm

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?

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xixipang
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Re: Lattice power output

Post by xixipang » Tue Nov 04, 2014 4:44 pm

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.

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Jaakko Leppänen
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Re: Lattice power output

Post by Jaakko Leppänen » Tue Nov 04, 2014 6:06 pm

If the same pin lattice is used at multiple assembly positions, then the tallies are scored in all of them, i.e. the result is averaged over all positions with the same lattice structure.
- Jaakko

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