Plutonium Lifespan in U.S. Weapons Much Longer Than Thought

By Walter Pincus
Washington Post Staff Writer
Thursday, November 30, 2006

The National Nuclear Security Administration said yesterday that studies have concluded that the plutonium used to trigger U.S. nuclear warheads and bombs will remain reliable for about 100 years, far longer than had been believed.

"These studies show that the degradation of plutonium in our nuclear weapons will not affect warhead reliability for decades," NNSA Administrator Linton F. Brooks said in a statement. An independent panel of renowned scientists and academics known as the Jason group reviewed the studies by the Los Alamos and Lawrence Livermore national laboratories and concluded that "most plutonium pit types have credible lifetimes of at least 100 years," according to the NNSA statement.

Results of the studies could affect the Bush administration's plans for building a new generation of nuclear weapons under the Reliable Replacement Warhead (RRW) program. A major reason for going to a new nuclear warhead was the belief that highly radioactive plutonium would degrade so much within 45 years that it could affect the reliability of currently deployed and stockpiled nuclear weapons, which were built beginning in the 1960s.

The present refurbishment program, which does not include the nuclear package, is directed at upgrading for 20 more years the aging conventional explosives and hundreds of the thousands of nonnuclear components in each weapon.

The father of the RRW program, Rep. David L. Hobson (R-Ohio), chairman of the House Appropriations subcommittee that handles funding for the nuclear weapons complex, said in a recent interview that he had heard that the plutonium study found that aging "is not as much of a problem as they thought it would be." As a result, he said, "that may throw some sand in the eye of RRW."

Robert W. Nelson, a senior scientist associated with the Union of Concerned Scientists, said yesterday that the studies "dramatically undercut the prime justification for having to rebuild the existing stockpile." The core plutonium component "will not need to be replaced for 50 years or more."

NNSA officials said yesterday that they do not agree that the plutonium findings mean that the RRW program does not need to go forward. "Plutonium aging is but one variable that can affect overall system reliability," the NNSA statement said. Brooks added: "It is now clear that although plutonium aging contributes, other factors control the overall life expectancy of nuclear weapons systems."

When Hobson first proposed the RRW program three years ago, it was designed to replace the Bush administration's proposal to study a possible nuclear "bunker buster" to go after underground fortified shelters or to look at new effects from nuclear devices that would destroy chemical or biological agents. Instead, Hobson wanted to rebuild the nonnuclear parts of the current stockpile to make the components safer, more secure and more reliable.

The administration then adopted RRW and by this year turned it into a program that would lead within 20 years to a new generation of nuclear weapons based on old tested designs, which would not require restarting an underground testing program. Los Alamos and Livermore are working on competing RRW designs with a winner expected to be selected soon.

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