Hecla and Kemp model the Burevestnik's direct-cycle reactor as emitting over 5 TBq of gaseous radionuclides per MW-hr

Because a direct-cycle nuclear turbojet passes ambient air directly through the reactor core rather than isolating it behind a heat exchanger, neutrons escaping the unshielded core activate the airstream. Modeling this with Monte Carlo neutron-transport simulations, Jake J. Hecla and R. Scott Kemp predict that the Burevestnik would generate "in excess of 5 TBq of gaseous radionuclides per MW-hr of flight." The activation products named include argon-41 (⁴¹Ar), the krypton isomers ⁸⁵ᵐKr and ⁸³ᵐKr, and carbon-14 (¹⁴C) — "some of which may be detectable using existing monitoring networks."

The finding is significant for arms-control verification: it implies the missile is not a covert system in flight but a moving radiological source whose signature existing sensor networks (such as radionuclide monitoring stations) might register. The prediction couples directly to the modeled reactor thermal power — a per-MW-hr emission rate scales with the reactor's output — so the several-megawatt cruise power translates into a substantial continuous release.

This is a model output about a classified weapon, not a confirmed measurement. Whether real detection data — for example around the 2019 Nyonoksa test-site radiation accident often linked to a Burevestnik failure — corroborates the predicted isotope signature is an open verification tracked in question-verify-burevestnik-radioactive-exhaust-corroboration.