Russia may be preparing to test an experimental nuclear-powered cruise missile called the Burevestnik, which has a range of up to 14,000 miles. The missile has failed in previous trials and caused an accident resulting in several deaths. Satellite images and aviation notices indicate movement and activity consistent with previous tests, raising concerns from the US.

https://thehill.com/policy/defense/4233615-russia-may-be-testing-nuclear-powered-missile-report/