WASHINGTON -- Sen. Patty Murray urged a National Park System Advisory Board on Tuesday to designate the B Reactor at the Hanford nuclear reservation a national historic landmark.

The board meets next week to consider the designation, which would be another step toward permanently preserving the world's first full-scale nuclear reactor.

"The B Reactor and the people who made it a reality have played an indelible role in our nation's history," Murray, D-Wash., said in a letter to William Baker, the chairman of the advisory board. "That history must be preserved so that we as a society have the opportunity to reflect on and learn from the important lessons this facility has to offer."

Interior Secretary Dirk Kempthorne will make the final decision on whether the B Reactor should be placed on the list of National Historic Landmarks. But it ultimately will be up to Congress to decide whether to save the reactor, the world's first production-scale nuclear reactor.

The National Park Service is expected to complete a study later this year on whether to include the B Reactor along with other Manhattan Project sites in Tennessee and New Mexico into a new national park.

The reactor is owned by the Department of Energy, which has indicated it will wait only until 2009 before deciding whether to "cocoon" it in concrete and steel for the next 75 years until a final decision is made on how dispose of it. Five of the nine former production reactors at Hanford already have been stabilized this way.

Park Service officials have been reluctant to move quickly on a new national park because of budgetary constraints. The Energy Department has indicated it was not in the museum business and was not interested in operating historic sites for tourists.

Murray, along with Rep. Doc Hastings, R-Wash., have been lobbying the Park Service and DOE to take steps to preserve the B Reactor.

The B Reactor took 11 months to build during World War II and operated for 20 years before being shut down. It was built at the dawn of the nuclear age and no one was sure whether the reactor, a pile of 75,000 graphite blocks, 36 feet high, 36 feet wide and 28 feet deep drilled through with 2,004 tubes to hold nuclear fuel, would even work.

The initial plutonium produced at the reactor was used in the world's first nuclear explosion at the Trinity Test Site in New Mexico and in the "Fat Man" bomb dropped on Nagasaki, Japan, during World War II.

The reactor now sits abandoned on the banks of the Columbia River.