RE: USRBIN-Neutron Balance Density

From: Joachim Vollaire <>
Date: Tue, 24 Jul 2012 12:40:34 +0000

Dear colleagues,

Maybe one precision at this was pointed out by Alberto, my answer below is not fully accurate. The neutron accounting in the neutron
balance density scoring is not done at bin surface crossing but interaction by interactions for the ones occurring inside the
concerned bin.


-----Original Message-----
From: [] On Behalf Of Joachim Vollaire
Sent: 21 July 2012 20:10
Subject: RE: USRBIN-Neutron Balance Density

Dear Guojun Hu,

Yes for bins overlapping region with fissile material the neutron balance is
likely to be positive while for areas with shielding or reflector material it should
be zero or negative. If you consider for example one neutron entering a bin,
inducing a fission leading to 3 neutrons. If 1 of the 3 neutron is captured
and the 2 others escape the bin then the neutron balance density is 1
(considering the bin volume is equal to unity).
Besides fissions, any y,xn reaction leading to neutrons (spallation if energy
sufficient) will also lead to a positive gain if the produced neutrons make it out of the considered bin.

Received on Tue Jul 24 2012 - 22:41:30 CEST

This archive was generated by hypermail 2.2.0 : Tue Jul 24 2012 - 22:42:31 CEST