From what I read online - Polonium 210 is the isotope used as the neutron initiator in nuclear weapons. But the half-life of this element 138 days.

This raises questions: how do substantial quantities of it survive in warheads that are stored in Silos for years ? Or what about a nuclear capable submarine that goes out for a mission that lasts many month ?

  • 1
    $\begingroup$ While Po-210 was used in WWII, it is not used in modern weapons. $\endgroup$ – Jon Custer Jun 16 at 1:12

Polonium 210 was used in the very first internal neutron initiators - Urchins and the like. Back then concern about storage of rockets for decades was not a priority. ICBM also did not existed (first ones were in 1957-58, 12 years after first nuclear test), nuclear bombs were supposed to be carried by long-range bombers - and hence could have been serviced before flight. Finally, war could have started next week - and everybody rushed to any solution which could be made faster.

Newer designs used external neutron initiators based on tritium/deuterium linear accelerator and deuterated/tritiated lithium target. Tritium-based ones are much easier to start, but also have limited shelf life. Deuterium-based initiators have no nuclear-related longevity limits.

You can have a hint on how neutron initiators operate by looking at specs of Dynamic Albedo of Neutrons device of Curiosity mars rover.

  • $\begingroup$ For the primary, yes, you have an accelerator-based D-T reaction. For the secondary, you have lithium deuteride. In an intense neutron flux the lithium-6 can convert tritium+helium. D-T reactions are driven by the compression and heating of the secondary. $\endgroup$ – Jon Custer Jun 17 at 13:20

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.