From Wapo
During the same week that CIA Director Mike Pompeo flew to Pyongyang for secret talks on ending North Korea’s nuclear program, U.S. weapons experts were studying a construction site near the Chinese border for clues that North Korean officials might be moving in the opposite direction.
Analysts pored over satellite images of the northern city of Chongsu, keying in on a large, red-roofed building that some experts suspect is a factory for making an ultrapure form of graphite. The material is essential for making nuclear reactors of the kind North Korea uses domestically, and, according to a new report, Pyongyang has recently attempted to sell the same nuclear-grade graphite to customers overseas.
The CIA has declined to comment about the mysterious building, the true purpose of which remains uncertain. But the questions over the construction project underscore a key difficulty in evaluating North Korea’s proposals to freeze or give up portions of its nuclear program: North Korea has a long history of concealing illicit weapons activity from foreign eyes.
Note that Iran is subjected to extensive UN/US inspections in contrast.
So what will they let us verify? Nothing, if the past is a predictor.