OAK RIDGE, Tenn. (AP) Hundreds turned out in this once-secret city that helped build the first nuclear bomb on Tuesday to support an upgraded and consolidated U.S. nuclear weapons program.

A few peace activists who regularly mark the anniversary of the Hiroshima bomb with protests outside the high-security gates of the Y-12 nuclear weapons plant in Oak Ridge also attended.

The first of two hearings in this eastern Tennessee city filled a 400-seat auditorium and brought some 80 speakers to the podium to register comments.

"I want to hear from the Oak Ridge community that Y-12 has a valuable mission," Y-12 site manager Ted Sherry said. "That it is important to this region. And that they fully support (its) continued operations."

A dozen local mayors responded with a letter saying their communities have backed the 4,600-employee Y-12 plant since it opened 65 years ago as part of the secret bomb-building Manhattan Project.

"The multitude of operations at Y-12 has always been supported by the citizens of our region," the mayors' letter said. "Each and every time our nation has faced a crisis requiring our region's support, Y-12, with its unique capabilities and skilled workforce, has readily stepped forward to serve."

U.S. Sen. Bob Corker, R-Tenn., who recently visited the Department of Energy plant, also issued a statement supporting Y-12.

But Ralph Hutchison of the Oak Ridge Environmental Peace Alliance said DOE has ignored a rising call, likely to be heard at future hearings, for a "no-production alternative" that would effectively turn the complex into a warhead-dismantling enterprise.

Hutchison also complained that all of the hearings are being held near weapons production sites, "which means they are only having it in communities where people make money building bombs."

As for the environmental impact of DOE's complex-wide decision later this year, opponent Bill Hickey of Detroit said the issue is bigger than any single site. "We know that mushroom cloud potentially covers the whole planet," he said.

Oak Ridge was the second stop on a 16-city tour to collect comments on the government's plans for a "smaller, more efficient, more secure and less expensive" nuclear weapons operation.

Under the plan, hundreds of old buildings would be demolished, site missions would be refocused and some new facilities built at the nation's eight nuclear weapons sites from South Carolina to California.

The preferred alternative of DOE's National Nuclear Security Administration is to consolidate weapons work at five sites the Los Alamos National Laboratory and Nevada Test Site in Nevada, the Pantex plant in Texas, the Savannah River Site in South Carolina and the Y-12 plant in Oak Ridge.

Y-12, which has long made uranium parts for every warhead in the U.S. nuclear arsenal and serves as the main storehouse for bomb-grade uranium, would become a "uranium center of excellence" under the NNSA's preferred option.

That declaration would be a boost to the work already under way at Y-12. A $500 million fortress-like storehouse for highly enriched uranium is nearing completion at Y-12, and early plans are being made for a new uranium processing plant that could cost up to $3.5 billion.

Already, some 250 old buildings have been demolished to modernize the Y-12 site, two privately developed office buildings have opened to house administrators and projections are being made to tear down another 15 Cold War-era building complexes totaling about 3 million square feet over the next decade.

"Absolutely, it will help us," Y-12 strategic planning manager Tom Smith said. "It will basically continue our momentum."

"We want the work. We want the jobs. And for the future peace of the world, it is great for this country," said Terry Bowers, a longtime iron worker and union leader at Y-12. "This place has been here for 65 years and we hope to continue to do the work for the country."

Y-12 nuclear weapons plant: http://www.y12.doe.gov/

Copyright 2008 The Associated Press.