11. Finally, promethium can be formed in nature as a product of spontaneous fission of uranium-238. 12. Pu-240 undergoes spontaneous fission as a secondary decay mode at a small but significant rate. 13. Detection was by spontaneous fission of the claimed parent isotope with half-life of 5 minutes. 14. Spontaneous fission has never been observed in the naturally occurring isotopes of these elements, however.15. He discovered spontaneous fission in 1940 with Konstantin Petrzhak. 16. In both cases, they were unable to detect any spontaneous fission from nuclei of bohrium. 17. The team identified a 2.2-second spontaneous fission activity contained within a volatile chloride portraying eka-tantalum properties. 18. Spontaneous fission was discovered in 1940 by Kurchatov19. Pu-240 has a high rate of spontaneous fission , which can cause a nuclear weapon to pre-detonate. 20. She was credited with the discovery that spontaneous fission is associated with the emission of neutrons.
