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Los Alamos National Laboratory Research Quarterly, Fall 2002
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Dateline Los Alamos

Lab Produces Qual-1 Pit

At a news conference held April 22, Director G. Peter Nanos announced that the Lab had achieved a major milestone: production of a nuclear weapon pit that meets specifications for use in the U.S. stockpile. Called Qual-1 because it was built with fully qualified processes, the pit culminates a six-year effort at the Lab's Plutonium Facility to restore the nation's ability to make nuclear weapons, a capability lost when the Rocky Flats Plant shut down in June 1989.

"Six decades ago, Los Alamos produced the first pit," Nanos said. "And today, on our 60th anniversary, we delivered to the Department of Energy a pit made with fully certified processes and made to all the specifications required for the nuclear stockpile." A pit is the fissile core of a nuclear weapon.

Linton Brooks, administrator of the National Nuclear Security Administration, noted that the achievement means that NNSA has met a key assignment set out by President Bush in his Nuclear Posture Review. "Since 1989 until today, we were the only nuclear power in the world that couldn't make a pit," Brooks said. "We now have the capacity that if something goes wrong with the stockpile, we can fix it." The Qual-1 pit is for the W88 warhead, which is carried on the Trident II D5 submarine-launched ballistic missile, a cornerstone of the U.S. nuclear deterrent.

The Department of Energy identified the Laboratory as the site for recapturing the nation's capability to manufacture pits in 1996, in part because we have the nation's only full-capability plutonium facility and have made pits since the 1940s. New pits are needed to replace those removed from the stockpile during periodic destructive surveillance and as reserves should surveillance studies identify pit problems that affect weapon safety, reliability, or performance.

To regain the pit manufacturing capability, the Lab modified the Plutonium Facility, acquired new equipment, and developed new fabrication technologies, materials, and processes. Forty-two processes are required to make a pit, all of which went through step-by-step design, engineering, and production reviews to confirm that they would result in pits that meet stockpile specifications. The processes also had to be qualified through extensive testing to demonstrate rigorous process control.

"All of these manufacturing processes meet today's health, safety, and environmental regulations, so some materials and processes differ from those used at Rocky Flats," Nanos said. For example, pits are now cleaned with environmentally responsible cleaners; the solvents used at Rocky Flats have been banned. While Rocky Flats used a wrought process to shape pits, the parts are now cast. Rocky Flats also used machine oil in all the manufacturing steps; pits are now dry-machined, with lubricant added only for the final pass.

To date, twenty pits have been produced as part of the Laboratory's pit manufacturing project. The first pit was completed in February 1998. In August 2002, the Lab made the first pit that used all forty-two processes required to make a certifiable pit. Qual-1 is the first pit manufactured that meets all quality requirements and could be placed in the stockpile if needed.

The Lab's next challenge is to complete the certification process for the newly manufactured pit by 2007. We will manufacture six pits a year from now until then to ensure that this milestone is met and to establish the capability to begin producing ten stockpile pits a year by 2007.—Jim Danneskiold

New Human Subspecies Announced
An international team of scientists, including Los Alamos geologist Giday WoldeGabriel, has announced the discovery of a new subspecies of modern humans, named Homo sapiens idaltu. Featured as the cover story in the June 12 issue of Nature, the discovery lends further credence to the hypothesis that modern humans originated in Africa.

In 1997, the team—known as the Middle Awash Research Group—discovered a fossilized skull and skull fragments of two adults and a child who lived in what is now the Afar region of northeastern Ethiopia, near the village of Herto. Argon-isotopic dating has put the fossils' age at 160,000 years old. Their age makes them the world's oldest fossils of near-modern humans, a fact alluded to by the reference to idaltu, which means elder in the Afar language. It took the team more than five years to successfully reconstruct and stabilize the fossilized remains.

The new subspecies is anatomically similar to modern humans. Before the Herto discovery, the oldest near-modern humans ranged from 90,000 to 130,000 years old and were found in Africa and the Middle East. The fact that H. sapiens idaltu predates the older (Middle Eastern) remains by 30,000 years supports the idea that modern humans originated in Africa and spread throughout the world from there.

Most significant to the research team, however, is the fact that the new subspecies is also unmistakably non-Neanderthal. The Herto fossils thus indicate that modern humans had evolved in Africa long before European Neanderthals disappeared. According to F. Clark Howell, a project co-leader from the University of California at Berkeley, the Herto fossils demonstrate that there never was a Neanderthal stage in human evolution and that Neanderthals were merely a branch of the evolutionary tree that later went extinct.

Following geological clues from satellite images and aerial photography, WoldeGabriel, lead geologist for the project, recommended that the team investigate the Herto site. After the fossils were discovered, he was also instrumental in characterizing the environment in which H. sapiens idaltu lived and resolving the fossils' age. Although much of Europe was under glacial ice at the time, the Herto subspecies lived near the shore of a large freshwater lake, a remnant of which exists today about a half mile west of its ancient shoreline, where the fossils were discovered.

Over the past decade, the Middle Awash Research Group has discovered a wealth of fossils in the Afar region. The team's finds include fossils of six early hominids ranging from one to six million years old in addition to the Herto fossils, its youngest find to date. —James E. Rickman 

 

 

Dean Martinez in the Lab's Plutonium Facility

Dean Martinez, a machinist in the Weapons Component Technology Group (NMT-5), adjusts a precision lathe before machining plutonium in the production area of the Lab's Plutonium Facility.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Scull fossil

Fossil of H. sapiens idaltu, housed in the National Museum of Ethiopia, Addis Ababa. Photo © 2001 David L. Brill/Brill Atlanta

 

 

 
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