Welcome to the forum, Oliver.
We need to inject a little perspective in the discussion about the proliferation of nuclear weapons. There are five "weapons-states" according to the Nuclear Non-Proliferation Treaty
and everyone else is "non-weapons states". I'm not saying the treaty is or isn't a good thing, I'm just stating its parameters. The weapons states are China, the United States, Russia, France, and the UK.
Restating this list in terms of the fraction of world carbon emissions in 2008
, it is China (23.5%), the United States (18.3%), Russia (5.7%), the UK (1.75%), and France (1.26%). Altogether they account for 50.5% of world CO2 emissions. Each of these countries has stockpiles of highly-enriched uranium (HEU) and weapons-grade plutonium (WGPu). They have the uranium enrichment technology to make more HEU, and they have the production reactors and chemical separations technology to make more WGPu. Each of these countries is in the process of destroying their nuclear weapons and degrading or destroying these stocks of materials. There is absolutely no reason whatsoever that a LFTR or U-233 would be used to fabricate a new nuclear weapon.The construction or operation of any nuclear reactor in any of these countries contributes ZERO to their potential for new nuclear weapons.
The construction or operation of LFTR in any of these countries contributes zero to their potential for new nuclear weapons.
These countries are destroying fissile stockpiles, not looking for more material. The UK is expending all kinds of thought about the 114 tonnes of plutonium at Sellafield. The best thing to do would be to burn it up in a reactor. The US and Russia are downblending HEU to LEU and using it to fuel light-water reactors. The US is building at incredible expense a MOX plant in South Carolina to make MOX fuel that no utility wants to burn in their reactors, JUST to fulfill a treaty commitment about the disposition of plutonium, regardless of the cost or logic. These are not actions that countries take who have a secret thirst to build new nuclear weapons from an un-characterized material from a yet un-constructed reactor. LFTR represents exactly ZERO threat in each of these five countries.
I'm sure we can all agree that LFTR technology, with its potential to replace all electrical generation in these countries, and its potential to be used to generate synthetic hydrocarbons to displace petroleum, would be a huge asset in the struggle to reduce global carbon emissions. With widespread use of LFTR technology in each of these countries, CO2 emissions could probably be driven to ~20% of current levels by the end of the century.
This would be a great accomplishment.
Next, consider the non-weapons-states who have significant CO2 emissions. These are India (5.8%), Japan (4.0%), Germany (2.6%), Canada (1.8%), and Iran (1.8%), and South Korea (1.7%).India
already has uranium enrichment and plutonium processing technology. If there was ever a country that might pursue proliferation based on thorium, it would be India, and they haven't done it even after decades of opportunity. India's economy is developing rapidly and they appear to be set on the use of fossil fuels for economic growth.Japan
has had nuclear power plants for decades and they have developed sophisticated plutonium separation technologies as well as fast-breeder reactor technology. But they haven't developed nuclear weapons and wouldn't based on thorium, when they already have so much plutonium and the capability to get more. Japanese CO2 emissions have gone way up
since they shut down their nuclear reactors after Fukushima, climbing from 374 million tons of CO2 in the year ended in March 2011 to 439 million tons of CO2 for the year, up 17 percent. This is an absolutely direct consequence of their trade of nuclear power for fossil fueled power, and is another example of the lie that nuclear reactors that are shutdown will be replaced with non-carbon sources. Germany
also has access to uranium enrichment and plutonium processing, as well as the technology for fast breeder reactors. Thorium-based technology would have no appeal to them in the development of weapons. Germany's decision to abandon nuclear will also lead to much higher CO2 emissions, as they replace nuclear power plants with lignite coal-burning power plants.Canada
specifically developed a nuclear technology (CANDU) based around use of natural uranium and heavy water, thus removing the need for uranium enrichment. Nevertheless, CANDUs produce plutonium but the Canadians have never sought to use it for nuclear weapons. A thorium-based fuel cycle would offer zero additional incentive for weapons development, when they already have hundreds of tons of plutonium in spent CANDU fuel and the ability to make more. If they wanted weapons-grade plutonium it would only take a simple modification of their fuel strategy to make it, since CANDU fuel bundles can be added and removed while the reactor is operating. But they haven't, and thus they won't. Canada's CO2 emissions will also be set to rise dramatically as they use tar sands in Alberta for energy production rather than non-carbon nuclear energy sources.Iran
is a country that probably does want nuclear weapons. But they have chosen the simplest and most effective route to getting material for those weapons, and that is uranium enrichment. Could they develop a LFTR on their own? Probably. Would they do so in order to produce material for weapons? No, not even the Iranians would do that because uranium enrichment is so much easier and proven. Iran also heavily subsidizes the internal use of petroleum products, which results in their very high CO2 emissions.South Korea
is a nation that has been very focused on the development of nuclear power for civilian applications. They have asked the US for permission to develop aqueous reprocessing of spent nuclear fuel and the US has denied that permission. (not sure why the US gets to tell them yes or no about that) Would the South Koreans develop nuclear weapons? Probably not so long as they are under the protection of the United States from North Korea, which has developed nuclear weapons using the same technique every weapons state did: namely irradiating natural uranium for a short period and chemically removing the plutonium. So would LFTRs in South Korea represent additional proliferation risk? No, not in a country that already has enriched uranium and plutonium in spent nuclear fuel.
So that's a run-down of the top ten countries in the world (accounting for nearly 70% of global CO2 emissions) and why none of them, even Iran, would use LFTR as a means of producing material for nuclear weapons. Each of these countries has the technological and economic base to develop LFTR, but if they did their goal would be energy generation, not the production of materials for weapons. Iran would be the sketchiest one, but likely even Iran wouldn't, because of their previous commitment to uranium enrichment.