Space.com has an article on the planned resumption of Pu238 production for power purposes (note the date on the article). It also links to a similar article on the subject from this time last year.
I find it surprising, to put it mildly, that we are relying on Russia to provide us with nuclear material for use in our spacecraft. In 5-7 years, however, we will apparently have a new production facility on-line (if DoE gets its wishes), which will enable us to produce enough fuel for upcoming nuclear-powered probes (possibly including Prometheus, but I don’t know if anyone yet knows what sort of fuel it will require).