Correct, but with a caveat. Here is what the Department of Energy's Office of Scientific and Technical Information (the lead agency in the technical aspects of nuclear proliferation and test ban enforcement) has to say about even very close range detection of nuclear weapons:
"Another difficulty is that several types of weapon designs can make it almost impossible, using radiation measurements, to confirm that a declared item is a weapon." (source)Of course there is always the argument that when discussing militarily sensitive technology that what they admit to today may well be a generation or two behind our real capabilities. But the task of satellite based radiation detection of nuclear warheads is daunting, to say the least, and may well be beyond man's capabilities to ever do.
Regards,
Boot Hill
palmer: I would imagine you would like to defend or explain your statements, I will wait until you do before I respond to the apparent disionformation you posted