The calculated distance (air line) between Pukchil-lodongjagu and Pyongyang is approximately 81 miles respectively 130 kilometers.
By car or train, the actual journey to Pyongyang is certainly longer, as only the direct route (as the crow flies) between Pukchil-lodongjagu and Pyongyang has been calculated here.
Air line (approximately)
130 kilometers
70 nautical miles