Search found 2177 matches

by Jaakko Leppänen
Wed Apr 08, 2020 11:00 am
Forum: Users
Topic: Coupled ngamma variance reduction on SMR
Replies: 8
Views: 93

Re: Coupled ngamma variance reduction on SMR

Can you send me the input by email?
by Jaakko Leppänen
Tue Apr 07, 2020 9:46 am
Forum: Users
Topic: Coupled ngamma variance reduction on SMR
Replies: 8
Views: 93

Re: Coupled ngamma variance reduction on SMR

It's very difficult to say why your calculations are running out of memory. One thing to check is that you are really running a single MPI task for each node. This is important, because the number of tasks multiplies the memory consumption, so you shouldn't run multiple tasks in the same memory spac...
by Jaakko Leppänen
Fri Apr 03, 2020 7:00 pm
Forum: Bugs, problems, questions & feeback
Topic: Impact on vertical lattices and detector fluxes
Replies: 7
Views: 91

Re: Impact on vertical lattices and detector fluxes

I completely missed the part about using the same random number seed. Yes... adding extra layers will affect the random number sequence when surface tracking is in use. The "set dt 1" card enforces the use of delta-tracking for every sampled track and should result in perfect reproducibility.
by Jaakko Leppänen
Fri Apr 03, 2020 1:07 pm
Forum: Users
Topic: How to get external source?
Replies: 31
Views: 15906

Re: How to get external source?

If this is a full-core model, why do you need the reflective boundary condition? The error on insufficient fissile material is most likely related to the sampling of initial fission source. Serpent samples source points uniformly throughout the geometry, and accepts the points that land on fissile m...
by Jaakko Leppänen
Fri Apr 03, 2020 12:52 pm
Forum: Users
Topic: Flux distribution - virtual detector outputs
Replies: 3
Views: 42

Re: Flux distribution - virtual detector outputs

That's right.

You can also specify the dividing volume in the dv entry of the detector card. Since the volumes are in general not known, the divisor is set to 1 by default. This works also for a Cartesian mesh detector, but not for a cylindrical mesh, where the cell size depends on radius.
by Jaakko Leppänen
Thu Apr 02, 2020 2:09 pm
Forum: Users
Topic: detector output file
Replies: 4
Views: 45

Re: detector output file

The 13th column in Serpent 1 is the number of scores. This is not printed in Serpent 2.
by Jaakko Leppänen
Thu Apr 02, 2020 2:08 pm
Forum: Users
Topic: Flux distribution - virtual detector outputs
Replies: 3
Views: 42

Re: Flux distribution - virtual detector outputs

The detector gives you the flux integrated over space, energy and direction (and time). The values are not divided by volume by default.
by Jaakko Leppänen
Thu Apr 02, 2020 11:59 am
Forum: Users
Topic: Coupled ngamma variance reduction on SMR
Replies: 8
Views: 93

Re: Coupled ngamma variance reduction on SMR

Your gbuf value is very large. This value determines the buffer for storing secondary gammas. In your case Serpent prepares to transport 1 billion photons per every neutron, which seems excessive. This is probably what causes memory allocation to fail.
by Jaakko Leppänen
Thu Apr 02, 2020 11:55 am
Forum: Users
Topic: How to get external source?
Replies: 31
Views: 15906

Re: How to get external source?

The first error is related to boundary conditions. Reflective boundary condition ("set bc 2") requires that the outer boundary is comprised of a surface that can be used to form a repetitive lattice. The second error means that the surface type is not supported by the surface source routine. Could y...
by Jaakko Leppänen
Tue Mar 31, 2020 4:17 pm
Forum: Bugs, problems, questions & feeback
Topic: Impact on vertical lattices and detector fluxes
Replies: 7
Views: 91

Re: Impact on vertical lattices and detector fluxes

Are you using reflective or periodic boundary conditions?

Also, source convergence in this type of calculations may be very slow. Have you tried tried repeating the calculations to see if the differences are consistent?