WASHINGTON -- A U.S.-based institute says North Korea is nearing completion of a light-water reactor that is intended to generate electricity but could add to concern over its nuclear program.

Satellite photos, the latest taken this month, show the North appears to be putting finishing external touches to the reactor at its Yongbyon nuclear complex, although it still faces considerable technical hurdles.

An analysis Wednesday by the U.S.-Korea Institute at Johns Hopkins School of Advanced International Studies says that the reactor could be fully operational during the first half of 2014.

But that depends on whether the North has produced enough low-enriched uranium to run it.

Experts say the reactor could potentially be used to produce plutonium for bombs, but it already has another reactor more suited to that task.