Search found 22 matches

by andrew.hall
Fri Mar 11, 2016 6:44 pm
Forum: Users
Topic: Discontinuity Factor Calculation
Replies: 5
Views: 2786

Re: Discontinuity Factor Calculation

Jaakko, I believe that would be helpful. What we're really after are the heterogeneous currents and fluxes on the 6 surfaces of the cube/cuboid. We would be able to produce our own homogeneous solutions for non-reflective boundary conditions. So as long as the heterogeneous currents and surface flux...
by andrew.hall
Thu Mar 10, 2016 7:18 pm
Forum: Users
Topic: Discontinuity Factor Calculation
Replies: 5
Views: 2786

Re: Discontinuity Factor Calculation

Jaakko, Ok, thank you for confirming the surface is super-imposed over the geometry. This is what I thought. And yes, I did receive warnings about negative values in the homogeneous flux solution. There are other regions where the values do match, it just happened that this region did not. I'm assum...
by andrew.hall
Thu Mar 10, 2016 1:40 am
Forum: Users
Topic: Discontinuity Factor Calculation
Replies: 5
Views: 2786

Discontinuity Factor Calculation

Hello, I've been experimenting with the "set adf" capabilities in Serpent2. I was attempting to extract ADFs from a 3x3 assembly problem and noticed that the discontinuity factor calculated in Serpent is not equal to the ratio of the heterogeneous surface flux to the homogeneous surface flux printed...
by andrew.hall
Mon Aug 31, 2015 9:45 pm
Forum: Methods
Topic: Detectors and Delta Tracking
Replies: 8
Views: 12258

Re: Detectors and Delta Tracking

I added "return 0.0" at the beginning of stopatboundary.c as you suggested. Here are the results: Original executable: Coarse mesh eigenvalue: 1.04082 +- 0.00032 Fine mesh eigenvalue: 1.04041 +- 0.00034 Modified executable (return 0.0): Coarse mesh eigenvalue: 1.04163 +- 0.00023 Fine mesh eigenvalue...
by andrew.hall
Mon Aug 24, 2015 8:22 pm
Forum: Methods
Topic: Detectors and Delta Tracking
Replies: 8
Views: 12258

Re: Detectors and Delta Tracking

Jaakko, Thanks for the quick reply. This was good information to know. However, I don't believe this is what was causing the difference as both my cases were either using detectors or not. We went back and performed a few additional calculations and this is what we found: -With Serpent2, both the fi...
by andrew.hall
Thu Aug 20, 2015 12:11 am
Forum: Methods
Topic: Detectors and Delta Tracking
Replies: 8
Views: 12258

Re: Detectors and Delta Tracking

I have a follow up question on this topic. By adding the set dt 1 card to a small 2 region problem, I was able to produce the same eigenvalue with a coarse mesh and a fine mesh (same overall global geometry). However, when I perform the same steps for a larger assembly problem, there is about a 10pc...
by andrew.hall
Wed Jul 29, 2015 9:31 pm
Forum: Methods
Topic: Detectors and Delta Tracking
Replies: 8
Views: 12258

Re: Detectors and Delta Tracking

I added the set dt 1 card to my inputs and they now produce the same eigenvalue. Looks like my input was switching to surface tracking. Thanks for the help!
by andrew.hall
Tue Jul 28, 2015 11:41 pm
Forum: Methods
Topic: Detectors and Delta Tracking
Replies: 8
Views: 12258

Detectors and Delta Tracking

I have a simple question that I think will explain something I'm seeing. If you add a surface detector to a problem geometry, does Serpent stop any neutron that crosses the surface and resample for the other side when using delta tracking? I've noticed that when I refine my mesh (use more gcus and m...
by andrew.hall
Sun Dec 21, 2014 10:12 pm
Forum: Bug reports
Topic: Unexpected up-scatter XS larger than down-scatter XS
Replies: 4
Views: 4860

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

Hi Tuomas and Jaakko, So I checked the reaction rates for the up-scatter and down-scatter: Up-scatter: RR = 3.98263E-02*2.90579E-03 = 1.15727E-04 Down-scatter: RR = 4.46476E+01*4.99760E-04 = 2.23131E-02 In this instance you are right that the reaction rate for down-scatter is higher. However, I also...
by andrew.hall
Mon Dec 08, 2014 10:03 pm
Forum: Bug reports
Topic: Unexpected up-scatter XS larger than down-scatter XS
Replies: 4
Views: 4860

Unexpected up-scatter XS larger than down-scatter XS

Hi all, I was running a simple 2 region pin cell problem in Serpent 1.1.19 and discovered that for one of the regions, the up-scatter cross section (2->1) is larger than the down-scatter cross section (1->2). The two regions are stacked on top of each other and I used 2 energy groups with the cutoff...