I am trying to calculate tritium breeding ratios in a FLiBe sphere for different thicknesses and material (Li) compositions. For this I am initially defining a neutron point source at the centre of a spherical shell of FLiBe. I have the following questions:
is choosing isotropic correct and sufficient to define a point source?
how do I correctly track the amount of tritium bred in my sphere? I have read several other threads here and the manual, but I am not sure whether I should use USRTRACK, USRYIELD or USRBDX or RESNUC?
What libraries should I not miss?
How do I then process the data depending on the detector? Can I do a spherical tracking?
Thank you in advance,
Alejandra
Input files
Please upload all relevant files. (FLUKA input file, Flair project file, user routines, and data files)
Isotropic source - for your simple model this is correct and sufficient.
If you wanted to work with a more complex geometry (i.e. a full blanket segment), you could also create a simple plasma source, using BEAMPOSit to create a ring source, and add blackhole regions to segment.
Ensure you have the low-energy libraries for the pointwise treatments installed.
In addition check in your transport settings that you have LOW-PWXS on, and to keep the neutron threshold low (PART-THR).
Using the physics card, check EVAPORAT and COALESCEnce are on.
Processing
If using RESNUCLEI, you will get tritium/primary - so in order to get the value as a tritium breeding ratio you’ll have to normalise with number of primaries.
Regarding the spherical tracking, do you mean to get the angular dependence?
In this case you could either segment your sphere and track by region.
Or use USRBIN which allows you to score in Cartesian coordinates, you would have to convert this then to its spherical dependence (there is no spherical meshing unfortunately) .
Thank you very much for your response. I managed to implement all of the above and am now struggling to interpret the results. Where do I find an explanation of the formats / contents of the .rnc plot and the sum.lis and tab.lis it generated? Thank you in advance and best regards, Alejandra
