-----Original Message----- From: mix...@bigpond.com > One can see that the cross section for neutron absorption by Ni62 at thermal energies (~ 2E-8 MeV) is about 14 barn.
Yes of course - that is a thermal neutron - which changes everything. There is no thermalization mechanism in this reactor so these are out of the question - and as stated, nickel is largely transparent to neutrons from nuclear reactions unless thermalized.
