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Space Reactors and Non-Proliferation

Conner Joyce, Matthew Orr, and Brooke Hollmann

In January 2018, NASA tested a nuclear reactor for use in space. The proposed reactor would power an enduring installation on a planetary surface. NASA envisions the planetary surface reactor, also known as Kilopower, as supporting President Trump’s desire to achieve “a sustainable human presence on the Moon by 2028.” 


NASA tested the Kilopower reactor with highly enriched uranium (HEU) fuel. HEU is the same material used to make nuclear bombs. For over 40 years the U.S. has led the campaign to limit the commercial use of HEU, hoping to prevent diversion of the sensitive material for proliferation or terrorism. Allowing NASA to research and develop HEU-fueled reactors would signal a significant departure from the U.S. policy of HEU minimization.


To help the reader understand the consequences of reneging on longstanding HEU minimization efforts, this site provides a comprehensive background on the downsides of fueling space nuclear reactors (SNRs) with HEU. It then offers a global update on SNRs to develop a watch list of states that have planned SNR launches or are capable of doing so. Finally, the site concludes with a brief policy prescription advocating for improved international regulation of SNRs. (Note: this project focuses exclusively on space reactors that produce electricity or power through fission, not through the radioactive decay of radioisotopes such as plutonium-238).

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