Search found 65 matches

by Tuomas Viitanen
Fri Dec 12, 2014 11:50 am
Forum: Bug reports
Topic: Unexpected up-scatter XS larger than down-scatter XS
Replies: 4
Views: 5888

Re: Unexpected up-scatter XS larger than down-scatter XS

Hi Andrew, First a disclaimer: I'm not at all familiar with the scattering matrices or group-generation in general, so I might be wrong. However, I think that the up-scattering cross section being larger than the down-scattering cross section makes sense, but it is the up-scattering reaction rate th...
by Tuomas Viitanen
Tue Nov 25, 2014 1:40 pm
Forum: Input
Topic: Track length estimator for detector burnups
Replies: 3
Views: 4360

Re: Track length estimator for detector burnups

Hi Jeremy, The track-length estimators are not compatible with burnup calculation, so things get a bit more complicated if you really need to use them. Before taking track-length approach you may try to increase the statistics by manipulating the size of your chamber. Assuming that the neutron flux ...
by Tuomas Viitanen
Mon Sep 15, 2014 9:45 am
Forum: Input
Topic: Multi-physics Interface File Temperture and Density Question
Replies: 4
Views: 4382

Re: Multi-physics Interface File Temperture and Density Question

Corrected the bug-fix in the previous post. The pointer should be loc0 instead of loc1.

Tuomas
by Tuomas Viitanen
Tue Sep 02, 2014 10:06 am
Forum: Input
Topic: Multi-physics Interface File Temperture and Density Question
Replies: 4
Views: 4382

Re: Multi-physics Interface File Temperture and Density Question

Hi! This is actually a numerical error in the code: the maximum and minimum temperatures of the nuclides are correctly set in the pre-processing phase, but when the temperature is retreived using the ifcpoint subroutine, suddenly T/1.0 is not anymore exactly equal to T. At least in my test case ther...
by Tuomas Viitanen
Thu Jun 05, 2014 1:10 pm
Forum: Users
Topic: BURNUP CALCULATION FOR A TRIGA REACTOR
Replies: 8
Views: 3769

Re: BURNUP CALCULATION FOR A TRIGA REACTOR

Hi again, I'm very sorry for misleading you! Now that I found the time to make some tests myself, it indeed seems that at least with Serpent 1.1.19 the shuffle card affects already the composition of the previous burnup step (previous "dep"), not the next one as I thought earlier. I will correct my ...
by Tuomas Viitanen
Mon Jun 02, 2014 9:52 am
Forum: Users
Topic: BURNUP CALCULATION FOR A TRIGA REACTOR
Replies: 8
Views: 3769

Re: BURNUP CALCULATION FOR A TRIGA REACTOR

Hi again, I think the shuffling property can only be used to update the list(s) of universes within the lattice(s), and it cannot be used to switch between two lattices (like in your example). I'm not quite sure what happens if you try to do so, but the property is certainly not meant for that and y...
by Tuomas Viitanen
Fri May 23, 2014 3:42 pm
Forum: Users
Topic: BURNUP CALCULATION FOR A TRIGA REACTOR
Replies: 8
Views: 3769

Re: BURNUP CALCULATION FOR A TRIGA REACTOR

Hello! 1) Even though it is not mentioned in the manual, Serpent 1 includes a "shuffling" property that allows the user to switch the positions of universities in a lattice in the middle of a burnup calculation. This property was actually developed when I was doing rod-wise burnup calculation for th...
by Tuomas Viitanen
Mon Apr 28, 2014 1:52 pm
Forum: Users
Topic: Temperature knobs
Replies: 16
Views: 6460

Re: Temperature knobs

Hi,

This topic has also been discussed in thread

http://ttuki.vtt.fi/serpent/viewtopic.php?f=3&t=1997

Tuomas
by Tuomas Viitanen
Wed Feb 19, 2014 3:17 pm
Forum: Methods
Topic: Doppler-Droadening and Thermal Scattering at the same time
Replies: 2
Views: 7620

Re: Doppler-Droadening and Thermal Scattering at the same time

Hi again, After looking at this issue for a while, it seems to me that there is nothing wrong with the upper energy boundary of the S(a,b) data after all. Thus, if you want to Doppler-broaden the free atom cross sections of materials with bound scatterers, you can simply disable the check by comment...
by Tuomas Viitanen
Tue Feb 18, 2014 6:16 pm
Forum: Methods
Topic: Doppler-Droadening and Thermal Scattering at the same time
Replies: 2
Views: 7620

Re: Doppler-Droadening and Thermal Scattering at the same time

Hi, Usually moderator temperature mainly affects the properties of a system via the density and the scattering properties of the material. Instead, the Doppler-broadening of the free atom cross sections has only very small effect since the moderator materials usually don't contain resonance absorber...