Thorium as a Tool for Nuclear Non-Proliferation in Iran

Sam Birer
March 7, 2011

Submitted as coursework for Physics 241, Stanford University, Winter 2011


Iran's aggressive pursuit of a domestic nuclear program in face of sanctions imposed by the international community has made headlines worldwide for several years. While Iran claims their nuclear program is meant purely to alleviate the pressure on the country's oil reserves, which are predicted to last for another 75 years if pumping remains constant, opponents point to the program as a cover for the development of nuclear weapons in violation of the Nuclear Non-Proliferation Treaty. [1] While it may appear that there can be no solution that would provide Iran with the ability to develop peaceful nuclear technology (as guaranteed by the NPT [2]) while giving the rest of the world peace of mind, developing Thorium as nuclear fuel may offer an alternative that would satisfy all parties.

Background on Thorium Power

Naturally occurring thorium is composed solely of the Th-232 isotope, which is a non-fissile but fertile isotope, meaning that fissile materials can be acquired from thorium through neutron absorption and subsequent nuclei conversions. [3] Light water reactors can be retro-fitted with seed-blanket cores called "Radkowsky thorium fuel cores" which allow for the use of thorium in existing nuclear plants with no or only minor changes. [4] RTF reactors have the benefit of being non-proliferative, which means that they produce as little as 1/50 as much plutonium as conventional light water reactors. [4, 5] In addition to these other benefits, thorium is also much cheaper and Th-232 is four times as abundant as all uranium isotopes combined! Finally, Nobel laureate Carlo Rubbia has claimed that Thorium can provide 200-times as much energy as Uranium per mass unit! [6] This means that the world's thorium supply could provide 800-times more energy than its uranium supply while generating only around 1/12 of the plutonium.

Thorium for Peace

If the world community is serious about trying to ensure that Iran does not produce nuclear weapons while honoring their treaty -guaranteed right to use nuclear technology peacefully, the United States and partner nations should work with Iran to convert the already extant Bushehr Nuclear Power Plant in Iran from a light-water reactor into a thorium fuel design. Although this solution does not take into account the political realities and difficulties that such a deal would engender, it would provide Iran with the nuclear power and prestige that it desires while ensuring that plutonium production in the country comes to a near standstill. Some analysts have also indicated that they feel Iran's current economic realities are going to force them to come to a nuclear deal sooner rather than later, and a reasonable offer from the West pushing thorium might be met with more openly than in times past. [7] This plant could also serve as a global model for peaceful nuclear development and help to develop the technology behind what may become an increasingly important source of fuel in the relatively near future.


Due to its relative abundance and incredible utility with already existing technology, Thorium could be a valuable tool to help countries develop peaceful nuclear programs with low risk of nuclear proliferation. As a global leader in nuclear technology and a leader in the push for an end to the spread of nuclear weapons, the United States and allied nations should provide aid to countries attempting to develop traditional uranium based nuclear programs to encourage them to switch to thorium-based reactor designs.

© Sam Birer. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.


[1] R. Flamini, "Iran's Nuclear Program Has a Long History," World Politics Review, 6 Feb 07.

[2] "Treaty on the Non-Proliferation of Nuclear Weapons," International Atomic Energy Agency Information Circular INFCIRC/140, 22 Apr 70.

[3] J. D. Lee and R. W. Moir, "Fission-Suppressed Blankets for Fissile Fuel Breeding Reactors," J. Fusion Energy 1, 299 1981.

[4] M.J. Higatsberger, "The Non-Proliferative Commercial Radkowsky Thorium Fuel Concept" in Thorium Fuel Utilization: Options and Trends, International Atomic Energy Agency, IAEA-TECDOC-1319, Novermber 2002.

[5] M. Kazimi, "Thorium Fuel for Nuclear Energy," American Scientist 91, 5 (2003).

[6] A. Evans-Pritchard, "Obama Could Kill Fossil Fuels Overnight with a Nuclear Dash for Thorium," The Telegraph, 29 Aug 10.

[7] J. K. Choksy, "Why Iran's Ahmadinejad Needs a Nuclear Deal," World Politics Review, 28 Jan 11.