Studies on the Use of Thorium in PWR

A study was taken up to assess the use of thorium in PWR type of lattice. The case study was done for the 17 × 17 square lattice fuel assembly (FA) of Westinghouse design used in modern PWRs namely AP1000 and EPR. This work describes some theoretical results obtained by loading thorium in oxide form as main fertile with either LEU or PWR grade Plutonium as fissile seed. The fuel assembly of PWR, i.e. 17 × 17 lattices with 4.9% enriched UO2 fuel is taken as reference Thorium has a prominent position in fuel cycle envisaged for Gen-IV reactors owing to its promises to contain the production of transuranic and minor actinides and introducing intrinsic anti-proliferation feature owing to inevitable production of U²³². Another aspect of Thorium loading which is worth mentioning is the possibility of burning of Plutonium and Uranium without further producing Minor Actinides (MA) and Transuranic (TRU). Properties of Thoria, such as its extraordinary stability against corrosion and high melting points being additional advantages, Thorium loading has been studied in considerable detail in functional and hypothetical nuclear reactors including in PWRs. PWRs being the most widely installed power reactor system makes it the most desirable target for the early deployment of thorium pending Gen-IV systems that are developed and become a common occurrence.