Search found 2357 matches

by Jaakko Leppänen
Mon May 24, 2021 9:20 am
Forum: Methods
Topic: Unable to sample fission source - try explicit definition
Replies: 3
Views: 322

Re: Unable to sample fission source - try explicit definition

The error message basically means that Serpent is unable to locate enough source points by random sampling. The most common case where this occurs is when you are running a standard criticality source simulation, but the fissile material covers only a small fraction of the geometry. Serpent samples ...
by Jaakko Leppänen
Fri May 14, 2021 10:38 am
Forum: Input
Topic: Fission matrix
Replies: 16
Views: 4438

Re: Fission matrix

Writing the source from a criticality source simulation using CSW and reading that into an external source simulation with fissions switched off (set nphys 0) is a good way to simulate simulate a critical reactor if the methodology doesn't allow an actual criticality source simulation. This same app...
by Jaakko Leppänen
Tue May 11, 2021 9:47 am
Forum: Development
Topic: Surface for Pressure Vessels
Replies: 2
Views: 257

Re: Surface for Pressure Vessels

Thank you. This seems useful. Can you also comment on the input parameters to the surface card?
by Jaakko Leppänen
Thu May 06, 2021 11:31 am
Forum: Bugs, problems, questions & feeback
Topic: Serpent2 verification/validation
Replies: 3
Views: 311

Re: Serpent2 verification/validation

I agree, but unfortunately we are quite resource-limited. For us it would be great if users were more active in publishing their own validation results (contributions can be added in the Wiki by registering as a user).
by Jaakko Leppänen
Wed May 05, 2021 12:28 pm
Forum: Bugs, problems, questions & feeback
Topic: Serpent2 verification/validation
Replies: 3
Views: 311

Re: Serpent2 verification/validation

Unfortunately we don't have any automated testing procedure available at the moment. There's a lot of validation done by users, but this information is scattered in reports and scientific publications. You may find something relevant for your case from the list of publications: http://montecarlo.vtt...
by Jaakko Leppänen
Wed May 05, 2021 12:20 pm
Forum: Old posts
Topic: Bug in PN scattering cross sections and diffusion parameters
Replies: 5
Views: 30971

Re: Bug in PN scattering cross sections and diffusion parameters

This paper discussing the efficiency of the CFE may also be useful:

https://doi.org/10.1016/j.anucene.2017.03.006
by Jaakko Leppänen
Wed May 05, 2021 9:22 am
Forum: Users
Topic: imposing inward current in criticality mode
Replies: 2
Views: 280

Re: imposing inward current in criticality mode

I think this issue is more related to the formulation of the criticality eigenvalue problem. The conventional definition (also used in Serpent) is that time dependence and external sources are dropped, and balance between source and loss terms is obtained by scaling the fission neutron production ra...
by Jaakko Leppänen
Wed Mar 31, 2021 10:55 am
Forum: Input
Topic: Record a detector per batch
Replies: 4
Views: 421

Re: Record a detector per batch

Actually, there is an option to include batch-wise detector results in the history output. This can be done by adding "dhis 1" in the detector card. Unfortunately this only works for single-valued detectors, and you also need to enable set the history file printing on "set his 1". This feature has n...
by Jaakko Leppänen
Mon Mar 15, 2021 1:11 pm
Forum: Input
Topic: Serpent crash with complex combination of surfaces and cell complements
Replies: 12
Views: 963

Re: Serpent crash with complex combination of surfaces and cell complements

Just a note... Cells like this probably lead to very performance. It's always better to divide complex parts into multiple universes. Serpent is different from MCNP in that way.