Thorium reactors would be far too slowly developed to have any real impact on climate change

“……..Timescale Claim: Thorium and the LFTR offer a solution to current and medium-term energy supply deficits. Response: The thorium fuel cycle is immature. Estimates from the UK’s National Nuclear Laboratory and the Chinese Academy of Sciences (see 4.2 below) suggest that 10-15 years of research will be needed before thorium fuels are ready to be deployed in existing reactor designs. Production LFTRs will not be deployable on any significant scale for 40-70 years. 4. Thorium / LFTR prospects
4.1 Timescales for thorium fuel The thorium fuel cycle is immature and unready for production-scale deployment. Although thorium fuels have been used in approximately 30 reactors, their nuclear dynamics and operational performance remain poorly characterised. India is already deploying thorium in its reactors as a component of mixed oxide (MOX) fuels comprising plutonium / uranium, and plans more of the same in its forthcoming Advanced Heavy Water Reactors. However, Norway’s Thor Energy and the UK’s National Nuclear Laboratory (NNL) both believe that considerable research, development and testing lies ahead before thorium fuels will be ready for operational use.
As the NNL states, “Thorium reprocessing and waste management are poorly understood. The thorium fuel cycle cannot be considered to be mature in any area.” It estimates that 10-15 years work is required before thorium fuels will be ready for use in current reactor designs, and that their use in new types of reactor is at least 40 years away. [The Thorium Fuel Cycle – An independent assessment, NNL, August 2010] 4.2 LFTR lead time: half a century
 The assessment of the Chinese Academy of Sciences as it embarks on its LFTR programme is that a production LFTR is 20-30 years in the future – rather shorter than the NNL’s estimate of 40 years (see 4.1). Given the hazards, such as the potential failure of reactor materials under intense neutron irradiation and chemical corrosion, risk-averse utilities and investors would want to observe the performance of any such full-scale LFTR for at least a decade and probably more, before embarking on any substantial LFTR programme.
The lead time for nuclear construction is of the order of a decade, so this could add a further 20-30 years before production LFTRs were deployed at full scale. The total lead time for LFTRs would therefore be a minimum of 40 years on the shortest estimates, or 70 years based on more conservative figures. …….