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Researchers revisit ‘first experiments’

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Advancing ideas for signature facility known as MaRIE

By Roger Snodgrass

Investigators at Los Alamos National Laboratory are combing through the history of modern science, looking for what might have been done differently.

In an exercise called “First Experiments,” 15 teams of researchers are working on answering a highly theoretical set of questions.

For example, in building the first atomic weapon, what experiments could be designed now that could be performed tomorrow, using the anticipated tools of LANL’s future materials research facility.

“That gap is what MaRIE needs to close,” said John Sarrao, program manager for a budding concept known as Matter-Radiation Interactions in Extremes.

He said a book of “First Experiments,” would be published in the spring, based on the researchers’ results.

MaRIE is a potentially far-reaching project designed to anchor LANL research into the coming decades.

The concept, which is still under development and beginning to take a more definite shape, is about an experimental facility that would be devoted to advanced materials research and charged with creating high performance materials of the future. This would be the stuff from which the most critical systems, like nuclear weapons, nuclear reactors and energy storage and distribution systems would be made. They would use complex, customized materials, guaranteed to withstand the most extraordinary conditions, 10 times stronger and more reliable.

The MaRIE concept won a key validation during the recent appropriation process, when a $20 million budget item for refurbishing the Los Alamos Neutron Science Center was approved by Congress.

Future plans for a physical plant for MaRIE overlay and depend upon a refurbished LANSCE, where materials research has been conducted for decades.

Among the additions envisioned for LANSCE would be a Multi-Probe Diagnostic Hall that would add an X-ray free-electron laser to the proton radiography of LANSCE.

“That lets you look at the interactions of defects and interfaces inside the material over time,” Sarrao said.

A Fission and Fusion Material Facility would provide a rare environment for studying irradiated materials, exploring questions like how materials resist becoming irradiated.

The M4 facility (Making, Measuring and Modeling Materials) will “discover by design” the future materials needed to withstand extreme conditions in critical environments.

One question revisited by the “first experimenters” has to do with the laboratory’s experience in manufacturing plutonium pits, a job inherited after the Rocky Flats plant stopped making the nuclear trigger at the core of the first stage of a thermonuclear weapon.

LANL’s task was how to do it in a new environment, requiring certainty of performance, without the ultimate reality check of a full-scale nuclear test. The United States had forsaken testing in 1992.

“Why did it take us $1 billion and a decade to certify plutonium pits?” Sarrao asked.

“Because the way they made them at Rocky Flats and the way we made them here is different,” he said.

A major change in pit manufacturing had to do with the fact that Rocky Flats pits were wrought, or forged, while LANL’s pits were cast.  Departing from the earlier method, LANL poured molten plutonium into molds.

Why was that a problem?

According to Paul Dunn, who led the lab’s metallurgy group and was quoted in an article in “1663,” a laboratory magazine, 90 percent of the certification process had to do with changing from a wrought to a cast pit.

“It’s a philosophical principle that if you change the processing, you change the materials’ performance,” he said.

“It’s also because we don’t have a good system for certifying materials,” Sarrao said in a recent interview. “It takes 20 years to certify a new material to use in a nuclear material. We do not have a predictive understanding of how materials are formed.”

The project will host a series of workshops in December on “Decadal Challenges for Predicting and Controlling Materials in Extremes.”

Overall Sarrao said the outlook for MaRIE is “pretty positive.”

“We’re marching along pretty steadily,” he said. “We’ve engaged the external community to help guide us in a good direction. We’re focusing on the ‘must-haves’ rather than the nice-to-haves.”

In FY-10, the project expects to propound its formal mission need statement and get on the books with its sponsors at the National Nuclear Security Administration as a fundable item.