Why is my SSW/SSR code not producing readable output from a KCODE run?

  • Thread starter Thread starter 19matthew89
  • Start date Start date
AI Thread Summary
The user encountered issues using SSW to write a surface source from a KCODE calculation, receiving errors when trying to use the output file with SSR. They noted that while a simpler setup with an SDEF source worked, the KCODE setup did not, indicating a potential conflict. After troubleshooting, it was discovered that the simultaneous use of the HSRC card and SSW was causing the problem. Removing the HSRC card allowed the SSW card to function correctly, producing a readable output file. Understanding the manual and ensuring correct syntax and file handling were emphasized as crucial for successful implementation.
19matthew89
Messages
46
Reaction score
12
TL;DR Summary
SSW/SSR works with SDEF run but not with KCODE run
Hi everyone,

I am trying to use SSW to write a surface source starting from a criticality calculation (i.e. a KCODE run). I am trying to write all the particles entering a cylindrical cell.
The code seems running smoothly and at last I end up having a file "output_ssw.w" which I expect to be the source code.

However, when I run the code trying to use that file as input file with SSR, launching the code as

Code:
MCNP  i=input.i n=output. RSSA=output_ssw.w

I keep on receiving this error:
"no particles accepted from the output_ssw.w file".
I also tried to have it opened with MCPL and I receive this error:
"ssw_load_particle WARNING: Could not convert raw MCNP6 SSW type (16777212) to pdg code
Warning: ignored particle with no PDG code set (raw ssw type was 16777212)."

If instead I try to run a simple run with an SDEF source (a sphere emitting neutrons inwards), no KCODE, and I use SSW to write the surface file "test.w", then it works and if I then try to emply it in a SSR run, the simulation works smoothly.

Do you know where the issue could be? Are SSW/SSR only suitable to write and read surface source from an SDEF simulation?

Thanks in advance
 
Last edited:
Engineering news on Phys.org
I struggled a long time with SSW/SSR. Never got confident with it. I especially had difficulty going from KCODE calcs to non-KCODE. I can only offer some things that I found that were tripping me up. Maybe they are not relevant to you.

First: Read the manual VERY carefully and VERY thoroughly regarding this feature. Make sure you are doing the syntax correctly. Look at the examples.

Be sure you are correctly writing the file using the SSW. You can get some indication by looking at the size of the file it creates. If you double the number of particles you expect to get written, does it (pretty close) double the size of the file? You can experiment with small numbers of files, like a few thousand.

Be sure you are using the SSR correctly. I had a huge amount of trouble figuring out how many particles were supposed to be in the file and how many to ask for when I used the SSR. And after that, how to normalize things. (But you are not getting that far.)
 
  • Like
Likes Alex A and 19matthew89
Grelbr42 said:
I struggled a long time with SSW/SSR. Never got confident with it. I especially had difficulty going from KCODE calcs to non-KCODE. I can only offer some things that I found that were tripping me up. Maybe they are not relevant to you.

First: Read the manual VERY carefully and VERY thoroughly regarding this feature. Make sure you are doing the syntax correctly. Look at the examples.

Be sure you are correctly writing the file using the SSW. You can get some indication by looking at the size of the file it creates. If you double the number of particles you expect to get written, does it (pretty close) double the size of the file? You can experiment with small numbers of files, like a few thousand.

Be sure you are using the SSR correctly. I had a huge amount of trouble figuring out how many particles were supposed to be in the file and how many to ask for when I used the SSR. And after that, how to normalize things. (But you are not getting that far.)
Thanks for the inouts.

Yeah...I thought (or simply hoped) that the runs with SSW/SSR would be easier and more straightforward but I'm really struggling understanding what is happening.
If I use first KCODE in the setup I'd like to use to write the source file it seems to work but it's not.

But if I use a simpler setup then it produces a working .w file. SO it seems there's something conflicting with SSW in my model. But I'm really having a hard time discovering it...
 
Solved issue: apparently there is a conflict between the simultaneous use of the HSRC card and SSW.

Once I removed the HSRC card, the SSW card worked perfectly fine and producing readable .w output file.
 
Hello everyone, I am currently working on a burnup calculation for a fuel assembly with repeated geometric structures using MCNP6. I have defined two materials (Material 1 and Material 2) which are actually the same material but located in different positions. However, after running the calculation with the BURN card, I am encountering an issue where all burnup information(power fraction(Initial input is 1,but output file is 0), burnup, mass, etc.) for Material 2 is zero, while Material 1...
Hi everyone, I'm a complete beginner with MCNP and trying to learn how to perform burnup calculations. Right now, I'm feeling a bit lost and not sure where to start. I found the OECD-NEA Burnup Credit Calculational Criticality Benchmark (Phase I-B) and was wondering if anyone has worked through this specific benchmark using MCNP6? If so, would you be willing to share your MCNP input file for it? Seeing an actual working example would be incredibly helpful for my learning. I'd be really...
Back
Top