Neutron Dosimetry Studies in EBR-II

Studies conducted in the EBR-II at 20 kW and at full power, 45 MW, confirmed the usefulness of threshold reactions, such as ⁵⁴Fe(n,p)⁵⁴Mn and ⁵⁸Ni(n,p)⁵⁸Co, for fast-reactor dosimetry. Also, there are few neutrons (<1%) below 10⁻² MeV in a fast-reactor core, and the (n,γ) reactions, such as ⁶³Cu(n,γ)⁶⁴Cu, become useful fast-flux monitors. Eighty percent of the core neutrons can cause (n,γ) reactions, while only 10% can cause (n,p) reactions. Results show that transport-theory calculations provide a good approximation to the spectrum in a fast reactor. Spectral-averaged cross sections for several EBR-II positions are presented.