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Blasts To Test Safety Of Old N-Weapons Underground Experiments Seek Answers On Aging Of Plutonium

Down the road from a desolate dry lake bed where America once set off atomic bombs, scientists are preparing for a series of much smaller tests, mere pops by comparison.

Unlike previous nuclear tests that showed what happened when nuclear bombs exploded, these underground experiments are aimed at determining the safety of the nation’s 9,800 nuclear warheads, whether weapons crafted in the heat of the Cold War are still reliable.

“This will help us maintain our existing weapons as they age,” said Robin Staffin, the Energy Department’s deputy assistant secretary for research and development.

The tests, known as subcritical experiments, are intended to show whether plutonium - the highly radioactive metal that is a key element of nuclear devices - will develop problems as it ages.

The days of actually firing a nuclear bomb at the remote desert site are over.

President Bush initiated a test moratorium in October 1992; President Clinton continued it, then signed the Comprehensive Test Ban Treaty last year.

Anti-nuclear activists say the subcritical experiments will circumvent the treaty and have asked a federal court in Washington to block the experiments. A hearing is scheduled June 17. Six protesters briefly blocked a road on Friday.

But scientists from the Lawrence Livermore and Los Alamos national laboratories are proceeding with their plans. Los Alamos plans an experiment code-named Rebound in late June; Lawrence Livermore plans one code-named Holog the following month.

Scientists will place pieces of plutonium about the size and shape of a silver dollar inside steel canisters and then smash them with an intense blast of conventional explosives.

The blasts will not produce a nuclear chain-reaction explosion, scientists and government officials say.

But they should show whether any characteristics of the highly radioactive metal change as it ages, such as becoming liable to breaking down.

The experiments will determine if the plutonium “behaves the same way as it did when it was new and we could test the weapons underground,” said Rob Hixson, a shock physicist for Los Alamos.