Guidance or tutorial of applying pseudo-material method

[GeorgeChen92]

Hi, I'm working on a project of coupled simulation involving MCNP and Fluent, and having trouble with how to apply the pseudo-material method in cross section handling. Is there any related material or tutorial? Or, does anyone know the procedure of applying the method and what kind of files the method actually modifies(e.g. xsdir or the material card in mcnp input file)?

 

[Toast]

Hi, I'm working on a project of coupled simulation involving MCNP and Fluent, and having trouble with how to apply the pseudo-material method in cross section handling. Is there any related material or tutorial? Or, does anyone know the procedure of applying the method and what kind of files the method actually modifies(e.g. xsdir or the material card in mcnp input file)?

The pseudo-material method modifies the MCNP material card in the MCNP input file. One would change the number density of the entries to reach an approximate mixture of materials with the same cross section as the desired material.

Eg if you wanted Lithium at 500 degrees and only had cross sections at 400 and 600 then you would add a fraction of both the 400 and 600 degree cross section.

There is an equation for finding the fraction of materials to add when making the pseudo-material http://neams.rpi.edu/jiw2/papers/ANS 92 Conlin.pdf

Are you planning on using pseudo-materials to get cross sections for particular temperatures? If so perhaps look at on the fly doppler broadening instead
http://www.casl.gov/docs/Martin.OTF.MC2013.Final.pdf

However sorts of questions are often answered on the MCNP email forum
https://laws.lanl.gov/vhosts/mcnp.lanl.gov/mcnp_forum.shtml

 

[GeorgeChen92]

The pseudo-material method modifies the MCNP material card in the MCNP input file. One would change the number density of the entries to reach an approximate mixture of materials with the same cross section as the desired material.

Eg if you wanted Lithium at 500 degrees and only had cross sections at 400 and 600 then you would add a fraction of both the 400 and 600 degree cross section.

There is an equation for finding the fraction of materials to add when making the pseudo-material http://neams.rpi.edu/jiw2/papers/ANS 92 Conlin.pdf

Are you planning on using pseudo-materials to get cross sections for particular temperatures? If so perhaps look at on the fly doppler broadening instead
http://www.casl.gov/docs/Martin.OTF.MC2013.Final.pdf

However sorts of questions are often answered on the MCNP email forum
https://laws.lanl.gov/vhosts/mcnp.lanl.gov/mcnp_forum.shtml

Thanks for your reply. I've read about the solution I was looking for and the OTF method you mentioned in other expertises. I think pseudo-material method should be sufficient in solving my problem but there's still a lot of work to be done for me to realize the method with scripts written with c++. Again, thanks for your help.