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

19matthew89 · Apr 16, 2023

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

Grelbr42 · Apr 17, 2023

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.)

19matthew89 · Apr 19, 2023

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...

19matthew89 · Apr 26, 2023

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.

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

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