Nuclear archaeology to distinguish plutonium and tritium production modes in heavy-water reactors

Several nuclear archaeology techniques have been proposed to determine historic plutonium production in dedicated nuclear reactors. These methods rely on sampling materials from the reactor core, or specially designed monitor tags, to examine suited isotopic ratios and deduce the amount of plutonium produced. However, some production reactors are capable of producing isotopes other than plutonium, such as tritium. If a reactor was declared to produce tritium, it would be crucial to confirm that it was in fact producing tritium, and not plutonium. In this paper, we describe how isotopic ratios discrepancies could be used to distinguish between plutonium and tritium production modes. We present results obtained from the simulation of reactor lattices inspired by Savannah River Site heavy-water production reactors and show that elements such as hafnium and tungsten can detect undeclared production of plutonium.