Search found 454 matches

by Ville Valtavirta
Wed Oct 20, 2021 1:49 pm
Forum: Input
Topic: Problem with multiple universes XS generation
Replies: 10
Views: 137

Re: Problem with multiple universes XS generation

Each superimposed universe can contain multiple cells, e.g. % --- Square surface with 1 cm side centered at (x,y) = (0,0) surf s2 sqc 0.0 0.0 0.5 cell cGC1 uGC1 void -s2 % first universe (uGC1) is inside surface s2 cell cGC2 uGC1 void s2 -s1 % second cell in first universe (uGC1) is inside surface s...
by Ville Valtavirta
Wed Oct 20, 2021 11:53 am
Forum: Input
Topic: Problem with multiple universes XS generation
Replies: 10
Views: 137

Re: Problem with multiple universes XS generation

Hi, you can also generate group constants in superimposed universes that are not part of the geometry, but indicate a specific sub-region of the geometry. Take for example the pin-cell case from the tutorial . We can add two cells (each belonging to a separate universe) to the input in a way that th...
by Ville Valtavirta
Wed Oct 13, 2021 3:56 pm
Forum: Users
Topic: Cumulative yield
Replies: 12
Views: 222

Re: Cumulative yield

Be sure to check the Serpent tutorial to learn about the basic Serpent use. For memory consumption see also set opti.

-Ville
by Ville Valtavirta
Fri Oct 01, 2021 12:39 pm
Forum: Users
Topic: Inconsistent particle XS values from detector between averaged tally and individual tally
Replies: 10
Views: 263

Re: Inconsistent particle XS values from detector between averaged tally and individual tally

When you averaged the capture cross sections across the particles in postprocessing, did you remember to use flux volume weighting for the homogenization? Homogenized cross sections cannot be averaged over larger regions through simple averaging.

-Ville
by Ville Valtavirta
Tue Sep 21, 2021 1:41 pm
Forum: Users
Topic: Pebbles motion
Replies: 13
Views: 935

Re: Pebbles motion

Hi,

I think uploading scripts to e.g. github and linking the page here should be OK.

-Ville
by Ville Valtavirta
Wed Sep 15, 2021 8:46 am
Forum: Users
Topic: Pebbles motion
Replies: 13
Views: 935

Re: Pebbles motion

Hi, could you explain why you do not want further decay for the discarded pebbles to help me understand what might be the best way to solve your problem? If you are writing restart files and _dep.m output files on a material-zone basis, you should already get the nuclide compositions of each pebble ...
by Ville Valtavirta
Wed Sep 01, 2021 12:41 pm
Forum: Users
Topic: Statistic uncertainty Keff for transients calculations
Replies: 3
Views: 242

Re: Statistic uncertainty Keff for transients calculations

Hi,

all of the result variables in <input>_res.m have their associated relative uncertainties printed out in the file. However, you will not get separate results from the different time-intervals in transient simulations.

-Ville
by Ville Valtavirta
Fri Aug 27, 2021 2:54 pm
Forum: Users
Topic: Decay heat - burnup step dependency
Replies: 5
Views: 307

Re: Decay heat - burnup step dependency

Hi Ondrej, the momentary decay heat estimation during full power operation has a significant component coming from very short lived nuclides, the concentrations of which are very sensitive to the potential time-discretization error in the depletion calculations. I would imagine that comparing decay ...
by Ville Valtavirta
Wed Aug 25, 2021 8:59 am
Forum: Users
Topic: general concepts
Replies: 19
Views: 830

Re: general concepts

To put it even more simply,

there is no specific power level that corresponds to some assembly that can be solved with neutronics. If the assembly is critical at the power level of, say 1 kW, it is critical at the power level of 1 MW too when only considering neutronics.

-Ville
by Ville Valtavirta
Tue Aug 24, 2021 9:07 am
Forum: Users
Topic: general concepts
Replies: 19
Views: 830

Re: general concepts

Hi, you have to set the normalization for the simulation yourself using one of the options in Serpent. See Serpent manual section "5.8 Source rate normalization". For pure neutronic calculations the choice of a power level in the system is arbitrary and, for that reason the normalization needs to be...