Thorium as a Reactor Fuel

Dr. J. Stephen Herring
Deputy Division Director for Nuclear Systems Design and Analysis
Idaho National Laboratory

Thorium is often suggested as a successor to uranium for fueling nuclear reactors.  Th has 3.9 times the crustal abundance of U, only one oxide and produces fewer actinides than U.  However, Th has no naturally-occurring fissile isotopes and its fuel cycle requires the breeding and separation of 233U.  This colloquium will discuss the production of thorium (and all the elements heavier than Ni) in supernovae and geoneutrino indications of overall U and Th inventories in the earth.  Present and potential resources of thorium and the distinctions between uranium and thorium geochemistry are described.  Neutronic analyses of U-Th fuels for the management of actinides, past reactor experiments and future designs will also be discussed.