The calculated distance (air line) between Yŏnggwang-ŭp and Sunan is approximately 109 miles respectively 176 kilometers.
By car or train, the actual journey to Sunan is certainly longer, as only the direct route (as the crow flies) between Yŏnggwang-ŭp and Sunan has been calculated here.
Air line (approximately)
176 kilometers
95 nautical miles