The Nuclear Threat Initiative, a private group in Washington led by Mr. Nunn, is setting up the new organization, known as the World Institute for Nuclear Security, or WINS. The institute is starting with $6 million in donations and plans to expand in the next two years to an annual budget of perhaps $8 million and a staff in Vienna of a dozen or so nuclear specialists.

The institute intends to provide a forum where nuclear security professionals can meet and share information about how to keep dangerous materials out of unfriendly hands. Its focus will be less on locks and cameras than on such management issues as how to keep guards alert and how to foil sophisticated attackers.

“These are common concerns,” said Corey Hinderstein of the Nuclear Threat Initiative. “But, until now, these professionals have had no way to talk to their peers about how to handle these kinds of challenges.”

The institute’s first director is to be Roger Howsley, who until recently was director of security for British Nuclear Fuels, which employs about 10,000 people.

The institute is being set up in Vienna mainly because of its proximity to the headquarters of the International Atomic Energy Agency, which provides some nuclear security advice to United Nations member states. Mohamed ElBaradei, the agency’s director, is expected to be at the unveiling on Monday and has strongly endorsed the institute.