Search found 2357 matches

by Jaakko Leppänen
Tue Dec 15, 2020 5:12 pm
Forum: Users
Topic: Negative reduced absorption macroscopic cross section
Replies: 4
Views: 543

Re: Negative reduced absorption macroscopic cross section

For most nuclides the threshold energies for (n,xn) reactions are > 5 MeV.
by Jaakko Leppänen
Mon Dec 14, 2020 1:26 pm
Forum: Users
Topic: Error from Wiki Example Input File
Replies: 3
Views: 433

Re: Error from Wiki Example Input File

Colon has special significance in cell surface lists (union operator). It may be that was some additional checks added in one of the updates.
by Jaakko Leppänen
Mon Nov 30, 2020 11:30 am
Forum: Serpent 2 scalability benchmark
Topic: Serpent 2 scalability benchmark
Replies: 8
Views: 5612

Re: Serpent 2 scalability benchmark

Are you comparing the running time to a case with 1 OpenMP thread per 2 MPI tasks? If so, I think there may be some overhead from data transfer between tasks. Try comparison to a single CPU run instead. I think the superior performance for hyper-threading results from more efficient use of CPU cache...
by Jaakko Leppänen
Tue Nov 24, 2020 1:08 pm
Forum: Gamma transport
Topic: Photo-nuclear reactions
Replies: 3
Views: 491

Re: Photo-nuclear reactions

Unfortunately photo-nuclear reactions are not included in 2.1.31 or the main development branch.
by Jaakko Leppänen
Mon Nov 16, 2020 2:00 pm
Forum: Bug reports
Topic: Reading ACE data
Replies: 6
Views: 2864

Re: Reading ACE data

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...
by Jaakko Leppänen
Mon Nov 16, 2020 11:39 am
Forum: Users
Topic: Microscopic XS of Boron-10
Replies: 4
Views: 513

Re: Microscopic XS of Boron-10

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...
by Jaakko Leppänen
Fri Nov 13, 2020 7:27 pm
Forum: Bug reports
Topic: Reading ACE data
Replies: 6
Views: 2864

Re: Reading ACE data

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?
by Jaakko Leppänen
Tue Nov 10, 2020 2:05 pm
Forum: Users
Topic: Pin power distribution with detector
Replies: 3
Views: 591

Re: Pin power distribution with detector

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...
by Jaakko Leppänen
Tue Nov 10, 2020 1:16 pm
Forum: Users
Topic: Pin power distribution with detector
Replies: 3
Views: 591

Re: Pin power distribution with detector

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?
by Jaakko Leppänen
Wed Nov 04, 2020 10:45 am
Forum: Users
Topic: About Burnup value convergence
Replies: 3
Views: 586

Re: About Burnup value convergence

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