Discussion forum for Serpent users

Unfortunately photo-nuclear reactions are not included in 2.1.31 or the main development branch.

It seems that there is something wrong with the nubar data. The six precursor groups are defined, but the decay constants are off (the first is 1.0 and the rest are zeros). The error comes from the energy distribution of delayed neutrons in the second group. Does MCNP print anything about the delaye...

Your detector definition means that you are integrating the product of flux and microscopic (n,alpha) cross section of material B10 over material mod_cold_0B and energy intervals specified by bin structure two_group. The result is divided by the result of detector 1. So if detector 1 is the correspo...

It's impossible to tell what the problem is based on the error message alone. I can take a closer look if the ACE file small enough to share?

It seems that the fuel pins in the assemblies are in a regular lattice, right? I think the easiest way would be to define four mesh detectors (11 x 11 x 25 cells), one covering each assembly position. When you combine the mesh detector with dr -8 void, you automatically get the fission power in each...

When you are scoring the power distribution, you don't need to divide the result by flux. So the dt entry is not necessary in the second detector. How exactly is your 2x2 assembly geometry set up? What is lattice 216 that you are refering to in the detector card?

Which code version are you using? Could you post the complete input here?

The energy is also off-scale (3.5 GeV). Do you have an external source definition? If so, check the units (Serpent uses MeV).

At the moment there is no option to output the scale. You can get the numerical values using mesh detectors and plot the same images with Matlab.

This is most likely related to delta-tracking and high rejection probability in the low-density plasma. There is an option to switch off the error completely:

http://serpent.vtt.fi/mediawiki/index.p ... set_inftrk

have you tried that?