Hanford's B Reactor was named a National Historic Landmark on Monday, recognizing the role it played in shaping 50 years of U.S. and world history.

Not only will that designation help efforts to preserve the reactor as a museum, but the growing interest in the reactor has led the Department of Energy to increase public access to it.

Starting in March, the reactor will be open to the public at least three days a week and no advance registration will be required for "drive-up" visits, said Jeffrey Kupfer, the DOE acting deputy secretary, during a visit to the reactor Monday.