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Quarterly Actinide Research ActinideLos Alamos National Research Laboratory Quarterly 2nd quarter 2002 Researchers cast first “spiked” plutonium alloy Major success in replicating how the stockpile ages Also In This Issue ■ Annual review assesses the state of science and technology in NMT Division ■ Technology transfer between Savannah River and the national labs ■ Plutonium Futures conference speakers set ■ Mary Neu is intrigued by actinides ■ “Eye of the Beholder” Nonprofit organization US Postage PAID Nuclear Materials Technology Division Albuquerque, NM Mail Stop E500 Permit No. 532 Los Alamos, New Mexico 87545 LALP-02-061 N u c l e a r M a t e r i a l s R e s e a r c h a n d T e c h n o l o g y Actinide Research Quarterly Actinide Research Quarterly is produced by Los Alamos National Laboratory NMT Division Director In This Issue About the Timothy George Cover Chief Scientist Kyu C. Kim 1 Researchers cast first “spiked” plutonium alloy Writer/Editor Meredith S. Coonley Designer 8 Annual review assesses NMT Division Susan L. Carlson Contributing Writer 11 Technology transfer between Savannah River Kathy DeLucas, IM-1 and the national labs Photographers photo by Joe Martz Michael D. Greenbank Joe Riedel Claudette Trujillo of the Printing Coordination Nuclear Materials Lupe Archuleta Science Group (NMT-16) assists with Distribution 17 Plutonium Futures conference speakers set rolling an enriched Sophie Vigil plutonium cookie on a laboratory-scale rolling 18 Mary Neu is intrigued by actinides mill during the historic casting of a “spiked” 20 “Eye of the Beholder” plutonium alloy May 13. Address mail to Cold-rolling the as-cast Actinide Research Quarterly plutonium emulates the Mail Stop E500 process used at the Los Alamos National Laboratory Rocky Flats Plant to Los Alamos, NM 87545 manufacture weapons components. To provide If you have questions, even more credibility to comments, suggestions, or contributions, please the process, the same contact the ARQ staff at grade of oil previously [email protected]. used at Rocky Flats, Texaco Regal ®, was Phone (505) 665-1079 used to lubricate the Fax (505) 665-5097 plutonium during rolling. The background image is of an enriched plutonium specimen mounted inside an aluminum fixture that will be tested using a 40-mm launcher. The story begins on the Actinide Research Quarterly highlights recent achievements and ongoing next page. programs of the Nuclear Materials Technology (NMT) Division. We welcome your suggestions and contributions. ARQ can be read on the World Wide Web at: http://www.lanl.gov/orgs/nmt/nmtdo/AQarchive/AQhome/AQhome.html. LALP-02-061 ii Nuclear Materials Technology/Los Alamos National Laboratory 2nd quarter 2002 Major success in replicating how the stockpile ages Researchers cast first “spiked” plutonium alloy os Alamos researchers celebrated a major success May 13 when they cast the very first “spiked” plutonium alloy, creat- L ing an accelerated-aging alloy that should age at a rate sixteen times faster than normal. As a result, in four years the researchers hope to have a material representative of sixty-year-old plutonium. Researchers will measure the spiked material to look for any age- related changes in key physics, engineering, and materials properties. The photo at right On the basis of these experiments, they’ll determine if the nation’s shows the plutonium- stockpile pits will last at least sixty years. 238 metal button that “This is probably the most technically difficult project we have was used as the ever attempted, at least metallurgically, at TA-55,” said J. David Olivas, starting material for the technical lead on the May 13 enriched project and former casting. Plutonium-238 is normally only Rocky Flats scientist. available in the form of The experiment plutonium oxide required years of because its radioactive preparation and in- decay produces so cluded replicating the much heat that the Rocky Flats pluto- material must be nium manufacturing present as a ceramic process. To that end, for it to be stable. The Los Alamos research- plutonium-238 button ers had to set up a shown here was capability that had reduced to the metal form from oxide never existed before: originally fabricated for a one-of-a-kind small- space-program heat scale casting, rolling, sources. Personnel in and machining opera- the 238Pu Science and tion at the Laboratory’s Engineering Group Plutonium Facility (PF-4). The researchers also had to reproduce key photos by J. David Olivas (NMT-9), who followed process steps and produce a material that matched Rocky Flats specifi- a procedure developed cations in a number of important properties. at DP Site in the And they did it on the first try. 1970s, performed the The research endeavor, called the Accelerated Aging of Plutonium reduction. This was (AAP) Project, is an experimental collaboration between Los Alamos the first time that plutonium-238 metal and Lawrence Livermore National Laboratories. Besides Olivas, the had been fabricated at AAP team at Los Alamos consists of Franz Freibert, principal investiga- TA-55. This button tor; Richard Ronquillo, lead mechanical technician; Claudette Trujillo, weighs about 100 materials accountability specialist; Chris Trujillo, mechanical technician; grams and is sitting at and David Dooley, graduate research associate. All are with the Nuclear about 200 degrees Materials Science Group (NMT-16). Celsius. These Los Alamos scientists, working with others in NMT-16, the Structure/Property Relations Group (MST-8), and the Detonation Science and Technology Group (DX-1), will examine the spiked material Nuclear Materials Technology/Los Alamos National Laboratory 1 Actinide Research Quarterly “Spiked” Plutonium Alloy with advanced characterization tools to measure aging-related changes in physical and chemical properties. Scientists at Livermore are conducting a parallel materials production and sample preparation activity. The two laboratories will exchange informa- tion and samples. The AAP activities support the Enhanced Surveillance Campaign goal to protect the health of the stockpile by examination of aged plutonium through the accelerated production of defects. The information obtained from this research will be used to predict material and component aging rates as a basis for annual certification, refurbishment scope and timing, and nuclear weapon complex planning. Ultimately, this work will form the key basis for Chris Trujillo of the establishment of pit lifetimes. Results of the research will also be used Nuclear Materials to make improvements to the basic surveillance program (see ARQ 1st Science Group quarter, 2001). (NMT-16) machines The new casting and machining capability also will enable Nuclear a Kolsky test specimen. A non- Materials Technology (NMT) Division to expand its research and water-based coolant development efforts in the study of weapons-related actinides and other is used to flood the special isotopes and materials. specimen during machining. Flooding Aging weapons alloy and stockpile stewardship ensures that the Researchers spiked the plutonium alloy cast May 13 with isotopic sample is not blends containing 7.5 overheated during percent plutonium- The casting yielded nine enriched plutonium the machining 238. The greater alpha “cookies,” one of which process, avoiding decay rate of the plu- the introduction of is shown here. The tonium-238 isotope nonaging-related thickness of this artifacts into the accelerates the self- miniature ingot dupli- plutonium sample. irradiation process cates the thickness of and enhances the self- the Rocky Flats ingots, irradiation damage as giving researchers a a function of time. good simulant for the Accelerating the self- next stage of process- irradiation aging ing: rolling the ingot into effects in weapons a sheet. alloys should provide critical data at extended effective lifetimes in the manifestation of aging effects on weapon design param- eters and component function, according to the researchers. 2 Nuclear Materials Technology/Los Alamos National Laboratory 2nd quarter 2002 The detection and prediction of changes in an aging stockpile are perhaps the most challenging and technically engaging aspects of science-based stockpile stewardship. Originally, weapons systems were designed with the During the aging expectation that the process, the nuclear components enriched samples would provide a rea- will be stored in sonable lifespan and incubators like the that the systems one in the photo at would be modern- left. The samples will ized or replaced on be cleaned before a consistent basis. being loaded in the Weapons systems incubator chamber, were not designed and then will be with the goal of long- stored in a pristine atmosphere for up to term (fifty or sixty four years. Four years) robustness. years of storage in Given the current the incubator in constraints and con- actual time is ditions in the nuclear equivalent to sixty weapons stockpile, years of aging in systems will require accelerated time. extended lifetimes The samples will be for various compo- removed periodically nents with only a from the incubators modest remanufac- and tested to obtain aging information at ture capability to intermediate times. replace excessively The incubator degraded units. chambers were Determining an appropriate response (recertification, refurbishment, designed and built at or remanufacture) ultimately depends on an accurate assessment of Lawrence Livermore individual component lifetimes. National Laboratory. The most acute challenge lies with testing and certification
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