The Russians tried powering a bunch of remote stuff with plutonium batteries during the Soviet era. It did not end well, and cleaning those up has been an ordeal. Pu-238 was also used in pacemakers. The basic problem is just that plutonium is toxic as hell.
I mean, US has been employing RTGs to power all kinds of stuff too, it's not just Russians which did. But yes, actually collecting and decommissioning them after the collapse of the Soviet Union has been an ordeal.
