OAK RIDGE, Tenn. (AP) -- Major construction on a $549 million high-security warehouse in Tennessee to hold the government's largest cache of weapons-grade uranium has been completed.

The National Nuclear Security Administration announced Tuesday the milestone had been reached on the Highly Enriched Uranium Materials Facility project located at the Y-12 nuclear weapons plant in Oak Ridge.

Construction on the 300-by-475-foot, reinforced concrete structure began in 2004. The state-of-the-art storehouse will replace several aging vault-like facilities at Y-12

NNSA spokesman Steve Wyatt said the warehouse is slated to be loaded in 2010 following extensive operational testing and reviews. Y-12 makes uranium parts for every nuclear warhead in the U.S. arsenal.

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