In the absence of new production, old weapons must be repaired and upgraded, often using nuclear material recovered from weapons that are being retired.

FORBES: Nuclear Paradox: Shrinking U.S. Arsenal Requires Huge New Expenditures

One of the things you know is that when people fool with these weapons, they're expensive to build, expensive to maintain, and expensive to secure the material that goes into making the weapons.

WHITEHOUSE: Press Briefing with President Obama and President Clinton

Now, such teams are also called out for hazardous material accidents, weapons of mass destruction and wide-area searches.

CNN: The brotherhood of Disaster City

"In this day and age, no one should be allowed to possess nuclear-weapons-usable material without providing an armed defense of that material, " said Edwin Lyman, a nuclear physicist with the Union of Concerned Scientists.

CNN: SHARE THIS

The dossier, which set out evidence about Saddam's alleged chemical and biological weapons programs, caused embarrassment for the government after it was revealed it included material copied from an American student's thesis that was posted on the Internet.

CNN: Blair accused over Iraq WMD threat

Fissile material in this form is difficult to use in a weapons program, U.S. and European officials say.

WSJ: Iran Talks Off to Shaky Start

Fissile material in this form is difficult to use in a weapons program, U.S. and European officials said.

WSJ: Iran Cools Nuclear Work as Vote Looms

This week's accord could result in little more than a return to a 1994 pact between America and North Korea, by which North Korea froze its operations at Yongbyon in return for fuel oil shipments and an agreement eventually to provide replacement nuclear reactors that could less easily be used to make weapons material.

ECONOMIST: Some cheer over North Korea

The U.S. and its allies are seeking to gain Iran's willingness to suspend its production of near weapons-grade nuclear material at its uranium-enrichment sites in return for economic incentives.

WSJ: Iran Says It Is Set for Nuclear Talks, but West Is Skeptical