Editing Automated depletion zone division (section)

== Division with symmetries ==

The automated depletion zone division can be used with universe symmetries (defined by the [[Input syntax manual#set usym|set usym card]]) to reduce the number of depletion zones. For the previous BWR fuel assembly geometry this could be done to account for the 1/2 symmetry of the pin layout. The trick is to define only the pins that will be included in the geometry:

[[File:div5.png]]

and then apply a symmetry card on the lattice universe (here 10):

 <nowiki>set usym 10 3 2 0.0 0.0 225 180</nowiki>

to cover the remaining positions:

[[File:div6.png]]

It is important to note that the positions that are overlapped by the symmetry should remain empty, because Serpent will process all pins included in the lattice card, regardless of whether they end up in the final geometry or not. The program will for example use excess memory if the pins are defined for the overlapped parts of the geometry. It is also important do define the volumes of the depletion zones [[Defining material volumes|manually]], because automated volume calculation <u>will always fail</u> in this type of structures.