Breeder Reactor - Thermal Breeder Reactors

Thermal Breeder Reactors

"The advanced heavy water reactor (AHWR) is one of the few proposed large-scale uses of thorium. India is developing this technology, their interest motivated by substantial thorium reserves; almost a third of the world's thorium reserves are in India, which also lacks significant uranium reserves.

The third and final core of the Shippingport Atomic Power Station 60 MWe reactor was a light water thorium breeder, which began operating in August 1977 and after testing was brought to full power by the end of that year. It used pellets made of thorium dioxide and uranium-233 oxide; initially the U233 content of the pellets was 5-6% in the seed region, 1.5-3% in the blanket region and none in the reflector region. It operated at 236 MWt, generating 60 MWe and ultimately produced over 2.1 billion kilowatt hours of electricity. After five years the core was removed and found to contain nearly 1.4% more fissile material than when it was installed, demonstrating that breeding from thorium had occurred.

"The liquid fluoride thorium reactor (LFTR) is also developed as a thorium thermal breeder. Liquid-fluoride reactors have many attractive features, such as deep inherent safety (due to their strong negative temperature coefficient of reactivity and their ability to drain their liquid fuel into a passively cooled and non-critical configuration), no need to manufacture precise fuel rods and the possibility of relatively simple continual reprocessing of the liquid fuel. This concept was first investigated at the Oak Ridge National Laboratory Molten-Salt Reactor Experiment in the 1960s. It has recently been the subject of a renewed interest worldwide. Japan, China, the UK, as well as private US, Czech and Australian companies have expressed intent to develop and commercialize the technology.