Nuclear Power from Thorium: Some Frequently Asked Questions

Abstract

From the inception of the nuclear power programme, the role thorium will play in sustaining supply of clean, safe and affordable nuclear energy for several centuries to come is being deliberated. The question is often raised why no commercial energy production unit utilising thorium has become operational till today. The present paper will essentially address this issue using a rather simplified language. The advantages offered by the Th-U²³³ fuel cycle in reducing the radioactive waste burden of the spent fuel and making it proliferation resistant are well known. In spite of these advantages, the absence of any fissile nuclide in the natural thorium makes it essential first to convert thorium into U²³³ by transmutation, and then, to utilise the latter as a fuel. It is for this reason thorium has all along remained as the nuclear fuel for the “future”. A fairly steady value of η (above 2) of U²³³ in a wide range of neutron energy spectrum makes it usable in different types of nuclear reactors—thermal, epithermal and fast. It is argued here that utilisation of thorium for energy production can be initiated without much delay using essential technologies available today provided a sufficient inventory of fissile material as a driver fuel is made available. However, some challenging technological tasks such as remote fabrication of U²³³-based fuel and industrial scale reprocessing of the corresponding spent fuel need to be addressed for operating a sustainable Th-U²³³ fuel cycle.