19 Jun (NucNet): Shanghai’s Institute of Applied Physics will begin construction in 2017 of two Generation IV experimental thorium nuclear reactors – a two-megawatt pebble-bed fluoride salt-cooled reactor and a 2-MW molten salt reactor.
The institute also said it would begin construction of a pilot 10-MW thorium based molten salt reactor in 2025.
The reactors all use solid thorium-uranium fuel cooled by molten salt and are one of the key reactor technologies identified for research by the Generation IV International Forum, which sees 13 countries and regions collaborate in the development of Generation IV nuclear energy systems.
The pebble-bed fluoride salt-cooled reactor will use a thorium-uranium once-through alternative fuel cycle and the molten salt reactor a thorium-uranium modified open fuel cycle.
According to the London-based Alvin Weinberg Foundation, which supports the development of next generation reactors, molten salt reactors represent “a revolutionary advance” in nuclear energy technology. They have many potential benefits over current nuclear reactors, including generating much smaller quantities of waste, far more efficient fuel use and lower construction costs. They have passive safety features, which ensure safe operation without human or mechanical intervention.
In March 2014 the South China Morning Post newspaper reported that the deadline to develop a new design of nuclear reactor using thorium for fuel had been brought forward by 15 years as China’s central government tries to reduce the nation’s reliance on smog-producing coal-fired power stations.
Thorium, a naturally occurring slightly radioactive metal, is more abundant than uranium, and research is being carried out into its potential use in nuclear reactors in a number of countries, notably China, India, Russia, Norway, Canada, the US and Israel.
The thorium-uranium fuel cycle has several potential advantages over a uranium fuel cycle, including thorium's greater abundance, superior physical and nuclear properties, better resistance to nuclear weapons proliferation and reduced plutonium and actinide production.
Thorium-based fuels and fuel cycles have been used in the past, but have yet to be commercialised.
According to the International Atomic Energy Agency and the OECD’s Nuclear Energy Agency, existing estimates of thorium resources total more than 4.5 million tonnes (reserves and additional resources). US mining company US Rare Earths has said deposits of highly concentrated thorium in the US would be large enough to supply the power needs of the entire country for centuries using thorium-fuelled nuclear reactors.