It is true the nuclear fission reactors currently used around the world are developments of technology originally developed during World War II as part of the US Manhattan Project to build a nuclear weapon before the Nazis did. Having succeeded in building nuclear bombs too late for use against Germany, they were used against the Japanese instead, to shorten a Pacific war characterised by extremely high levels of US casualties as the Japanese defended their home islands (27,000 in Iwo Jima and 49,000 in Okinawa).Thankfully, they have never been used again, even when General MacArthur requested their use during the Korean War. That historical experience has quite naturally coloured perceptions of nuclear power ever since. But is it time now to look at nuclear power more objectively, comparing its risks and benefits to those alternatives on offer that can supply the world with the energy it needs to live lifestyles we have taken for granted?The capacity to produce weapons-grade uranium and plutonium from the existing nuclear fission industry is what alarms institutional investors. The alternative that has always been discussed has been nuclear fusion. The combining of hydrogen nuclei to produce helium, as the sun does, has been the fabled clean energy solution. Unfortunately, its future success has always been predicted to be 30 years away, and has been so for the last 50!There is another alternative, though, that the nuclear sceptics should consider. A better alternative to the uranium and plutonium nuclear fission reactors may be thorium-fuelled nuclear fission reactors. They have the advantage over uranium and plutonium reactors in that there is considerably reduced nuclear waste. In addition, thorium itself is much more abundant than uranium.The issue of nuclear proliferation still exists, although it has been argued that the US shut down their research into thorium reactors in 1973 primarily because the thorium fuel cycle did not have weapons applications. Thorium-based fuel for nuclear power would be extremely difficult to use in the secret manufacture of a nuclear bomb because the spent thorium fuel contains the isotope of uranium U-232, as well as U-233. Whilst it is possible to use U233 in a nuclear weapon, the U232 it is mixed up with decays rapidly with the production of strong gamma rays, which creates significant problems of handling and greatly boosts detectability.Currently, the thorium-cycle nuclear power is being actively researched by a number of countries, including China and India. India, for example, has limited supplies of uranium but large amounts of thorium in the beach sands of Kerala and Orissa, which have rich reserves of monazite, which is 8-10% thorium, according to the government of India. Tourists sunning themselves on some of the fabulous beaches of Kerala may not realise what lies beneath them!Whatever the merits of thorium over uranium/plutonium in the creation of safe nuclear power, if global warming through carbon dioxide build-up is an existential threat to human civilisation, then choices do have to be made on the risks and rewards of alternatives to burning fossil fuels.The total number of direct deaths arising from nuclear energy, including accidents such as Chernobyl and Fukushima, is less than 100. Including estimates of increased cancer deaths arising from the 600,000 or so people exposed to increased radiation raises the figure to perhaps around 4,000. In contrast, direct deaths from coal mining would lie in the thousands per year, whilst indirect deaths caused by pollution from the burning of coal would also be a multiple per year of the total estimated indirect deaths arising from the nuclear accidents.Perhaps nuclear energy has been dismissed too readily by countries and institutional investors alike.Joseph Mariathasan is a contributing editor at IPE Joseph Mariathasan questions the wisdom of considering all things ‘nuclear’ in a negative light‘Nuclear’ has become a dirty word – understandably when applied to weapons but less so when applied to power. Of course, there are arguments that can be made in justification. There are concerns over possible links with nuclear weapons and issues over dealing with radioactive wastes. Even countries can choose to damn the concept. Germany closed down all its nuclear power stations following the Fukushima disaster.Yet the biggest existential issue facing the world is global warming caused by the build-up of carbon dioxide, primarily from the generation of power. Alternative energy sources such as solar, wind and tidal do not appear to have the capacity to be able to supplant completely the carbon dioxide-producing fossil fuels, or even make a major dent in their usage.What can replace fossil fuels is nuclear power. A long-term, effective solution to the existential threat of global warming could be the widespread use of nuclear energy to generate electricity, combined with a shift towards electric cars that has already begun.