To be efficient as a power plant a reactor needs to spend most of its time operating. If you want to make nuclear material for bombs with this kind of reactor i

To be efficient as a power plant a reactor needs to spend most of its time operating. If you want to make nuclear material for bombs with this kind of reactor it will enter a number of startup-shutdown cycles, which would make it inefficient, and would be very noticeable. Of course they recently extended the coolant outflow quite a bit to mask the thermal signature of operation, but it should still be possible to determine a rough operational schedule.