A Neutronics Study of the 1945 Haigerloch B-VIII Nuclear Reactor

We present a neutronics study of the German B-VIII nuclear reactor, which was built in Haigerloch, Germany, between February and April 1945. We used the Monte Carlo code MCNP5 to estimate its effective nuclear-multiplication constant k_eff and its corresponding neutron-multiplication factor M, its neutron energy-distribution spectrum, and its neutron-flux distribution in its central horizontal and veritical planes for both thermal and fast neutrons. Our calculations agree well with the known measurements the German scientists made, who determined M to be 6.7. We also found that the effect on k_eff of impurities in the graphite of its neutron reflector could have been only on the order of few hundredths of a percent.