The Energy Department plans to build a storage site for high-level nuclear waste from U.S. weapons systems.

Energy officials, who didn't give a timeline for developing the repository, said they will start by identifying potential locations and gain local support for the project. President Barack Obama signed a memorandum Tuesday backing the department's plans.

An administration official who requested anonymity to discuss the plan said building the storage site probably will face fewer obstacles than establishing a repository for waste from nuclear power plants.

That's in part because U.S. defense programs produce about 5 percent of all nuclear waste, the official said. Waste from generating electricity accounts for 85 percent of the total.

Obama has blocked plans to build a permanent storage facility for both nuclear and commercial waste at Yucca Mountain in Nevada.