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0K cross section data in the base version

Posted: Mon Nov 11, 2013 7:05 pm
by xixipang
Hello, I have just got updated to 1.1.19 and would like to run a simulation with consideration of doppler-broadening rejection correction(BDRC).

According to the manual I wrote

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set dbrc 4.000E-7 2.100E-4 92238.00t 94239.00t
and in the running anerror would be found:

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DBRC nuclide 92238.00t not found
And then I mentioned that in the "Important Note" section, that "0K cross section data is not available in the cross section libraries distributed with the current base versions."

After reading the source file "processmaterials.c" I found the reason of the error is that programs can't find the correspond name in the xsdata file.

Just to try the function I run the input file with

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set dbrc  4.000E-7 2.100E-4
and it did run. The K-eff value with dbrc is around hundreds pcm smaller als the value without dbrc. But without the specification of some certain nuclides, I am not sure about if dbrc is added and how the value is.

Could anyone told me that where should I supposed to get this 0K cross section files? Or The file is already there and I just need to set something right?

Thank you!

Re: 0K cross section data in the base version

Posted: Tue Nov 12, 2013 1:38 pm
by Tuomas Viitanen
Hi,
You managed to spot two problems in the Serpent 1.1.19 and manual in your post. Thank you for pointing them out :)
  • - There seems to be an error in the Serpent manual: the cross sections that should be given to the set dbrc card are continuous-energy (.xxc) cross sections, not thermal scattering (.xxt) cross sections. Thus, the correct dbrc card entry for U-238 is

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    set dbrc 4.000E-7 2.100E-4 92238.00c
    - Looks like Serpent 1.1.19 is missing some sanity checks for the DBRC input: including no nuclides at all in the list of DBRC nuclides is equal to not using DBRC at all. I'm a little bit surprised you saw some difference between the eigenvalues with and without the zero-nuclide input for DBRC.
Since the 0 K cross sections are not available in the NEA / RSICC distribution package, you need to obtain them somewhere else. One possibility is to produce them yourself from the ENDF data using cross section processing code NJOY.

Tuomas

Re: 0K cross section data in the base version

Posted: Wed Nov 13, 2013 9:01 pm
by xixipang
Thank you very much for your answer:)

Re: 0K cross section data in the base version

Posted: Thu Nov 14, 2013 12:52 am
by xixipang
Hello Tuomas, I am sorry to say that this is not yet finished...

Well, when you said about the right entry, I remembered that I have tried that and here is what I got:

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DBRC nuclide 92238.00c not found
But there is no 92238.00c in xsdata, so I guess, I have to generate 0K data myself, and till then I can use DBRC for the first time, right?

Thanks:)

Re: 0K cross section data in the base version

Posted: Thu Nov 14, 2013 12:29 pm
by Tuomas Viitanen
Just like you said: You need to first generate (/obtain by other means) 0 K data and only after that you can use DBRC.

Tuomas