A US diplomat will head to North Korea to watch the communist nation blow up the cooling tower at its main nuclear reactor, a South Korean official said Wednesday. Sung Kim, the top US State Department expert on Korea, will travel Thursday to North Korea for the planned destruction of the cooling tower at its Yongbyon nuclear reactor, an official at South Korea's Foreign Ministry said. He spoke on condition of anonymity, citing ministry policy. The US Embassy confirmed Kim had arrived in Seoul on Tuesday night and was heading to North Korea on Thursday. It has not been confirmed when North Korea will blow up the 20-meter-tall tower. Media reports have said it will occur Friday, a day after North Korea is expected to submit a long-delayed list of its nuclear programs. North Korea has invited foreign TV stations to broadcast the tower's destruction to demonstrate its plan to give up its nuclear ambitions. The cooling tower is a key element of the reactor, but its destruction at this point does not have much meaning because the reactor has already been nearly disabled so it cannot be easily restarted to produce plutonium for bombs. North Korea agreed last year in negotiations with the United States and four other nations to disable the reactor and other key Yongbyon facilities, and fully account for all its nuclear programs. However, it failed to meet an end-of-2007 deadline to declare its nuclear programs.