“Small-scale chemical reprocessing of irradiated thorium can create an isotope of uranium — uranium-233 — that could be used in nuclear weapons. If nothing else, this raises a serious proliferation concern.”
ScienceDaily (Dec. 5, 2012) —
Thorium is being touted as an ideal fuel for a new generation of nuclear power plants, but in a piece in this week’s Nature, researchers suggest it may not be as benign as portrayed.
The element thorium, which many regard as a potential nuclear “wonder-fuel,” could be a greater proliferation threat than previously thought, scientists have warned.
Writing in a Comment piece in the new issue of thejournal, Nature,nuclear energy specialists from four British universities suggest that, although thorium has been promoted as a superior fuel for future nuclear energy generation, it should not be regarded as inherently proliferation resistant. The piece highlights ways in which small quantities of uranium-233, a material useable in nuclear weapons, could be produced covertly from thorium, by chemically separating another isotope, protactinium-233, during its formation.
The chemical processes that are needed for protactinium separation could possibly be undertaken using standard lab equipment, potentially allowing it to happen in secret, and beyond the oversight of organisations such as the International Atomic Energy Agency (IAEA), the paper says.
The authors note that, from previous experiments to separate protactinium-233, it is feasible that just 1.6 tonnes of thorium metal would be enough to produce 8kg of uranium-233 which is the minimum amount required for a nuclear weapon. Using the process identified in their paper, they add that this could be done “in less than a year.”
“Thorium certainly has benefits, but we think that the public debate regarding its proliferation-resistance so far has been too one-sided,” Dr Steve Ashley, from the Department of Engineering at the University of Cambridge and the paper’s lead author, said.
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