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3rd quarter 2001 TheLos Alamos National Research Laboratory N u c l e a r M Quarterlya 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 a U.S. Department of Energy Laboratory

Improved Differential Scanning Calorimeters Enable Scientists to Make More-Accurate Studies In This Issue Researchers are using a of and Its Alloys technique called power- compensated differential 4 scanning to Investigating a Viable The Stockpile Stewardship Program has created a renaissance study phase transforma- Fuel Form for ATW in plutonium at Los Alamos with its mandate to tions in plutonium. In this manufacture new pits as well as to understand in detail the effects close-up, a capsule of aging on older stockpile weapons. containing a plutonium Scientists conducted research on metallic plutonium and specimen (the small white container held in plutonium alloys throughout the 1950s, ’60s, and early ’70s, but the tweezers) is being materials research in this area slowed significantly in the following loaded into one of two years. The Lab’s commitment to stockpile stewardship has mobi- furnaces in a calorim- lized a strong effort in the Nuclear Materials Technology (NMT) eter. The furnaces are and Materials Science and Technology (MST) divisions to push the the recessed areas in the center of the photo. understanding of plutonium and its alloys to a new level. The plutonium specimen will be placed in the furnace on the left; the furnace on the right remains empty and is Focus on Students: used as a reference.

6 Students are Vital to the Lab

8 Nuclear Engineer Steven Alferink

10 Social Scientist Andrew Koehler

12 Susan Oldham

14 Newsmakers

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Nuclear Materials Technology/Los Alamos National Laboratory 1 Actinide Research Quarterly

Differential Scanning

continued from page 1 research that previously were beyond the One area of materials research receiving capability of older DSC instruments. renewed attention is the of The state-of-the-art differential scanning phase transformations and self-irradiation in calorimeter used today at the plutonium char- plutonium and its alloys. acterization laboratories in the and This article was This area of study is particularly interesting Research (CMR) Building is com- contributed by to researchers because plutonium undergoes posed of two independent furnaces. One fur- Dan Schwartz more phase transitions than any other element. nace contains a specimen for analysis while (NMT-16) and It transforms through six different crystal the other is empty and used as a reference. Tom Zocco (NMT-5). structures (alpha, beta, gamma, delta, delta The furnaces are heated by separate prime, and epsilon) at atmospheric pressure as elements that follow a programmed tempera- it is heated from room temperature to its melt- ture vs. time profile. ing point. A compensating circuit maintains the Researchers are using a powerful technique, temperature difference between the specimen differential scanning calorimetry, or DSC, to and reference furnaces as close to zero as pos- further the understanding of the plutonium’s sible, while the instrument measures the phase transitions and study the transformation amount of power input that is required to keep phenomena in detail. the temperature difference to a minimum. The type of DSC primarily used here, This power input is directly related to the “power-compensated” DSC, was developed heat required to change the temperature of the in the mid-1960s to improve measurements of specimen—a quantity called the heat capacity key thermodynamic properties of materials. of the specimen. In recent years, DSC has undergone A simple integration of the power input significant improvements in sensitivity and con- over time yields another important thermody- Researcher Dan trol, allowing researchers to revisit old areas of namic quantity—enthalpy. When a material Schwartz of Nuclear plutonium research with new levels of accuracy. undergoes a phase transition (for example, Materials Science The improved instruments also are when it melts or changes crystal structure), it (NMT-16) loads a allowing scientists to explore new areas of either releases or absorbs heat. capsule containing a In power-compen- plutonium specimen into the furnace of a sated DSC, this causes differential scanning the instrument to in- calorimeter. Once crease power input to Schwartz loads the compensate, until the specimen, he will phase transition is close the cover over complete. The DSC the furnaces and begin instrument in the the measurement. CMR Building is ca- Everything is done in pable of measuring a ventilation hood to with high purity stan- protect the operator dards the onset tem- from the plutonium specimens during the perature for phase loading and unloading transitions to an accu- process. The equip- racy of plus or minus ment is located in the 0.05 degrees Celsius, plutonium characteriza- and heat capacity and tion laboratories in the enthalpy to plus or Chemistry and minus 2 percent. Metallurgy Research The instrument (CMR) Building. also is capable of

2 Nuclear Materials Technology/Los Alamos National Laboratory 3rd quarter 2001

12.0 These graphs show making these measurements at temperatures δ' − ε ranging from minus 150 C to 730 C. 10.0 heat flow as a function Recently, the availability of very high α − β of temperature for purity zone-refined plutonium, manufactured 8.0 pure plutonium. The top graph shows the by Jason Lashley of Structure and Property 6.0 β − γ γ − δ heating curve; the Relations (MST-8), prompted researchers to 4.0 bottom graph shows δ − δ remeasure the onset temperatures and enthal- ' the cooling curve. pies for all the phase transitions in plutonium. 2.0 The measurements resulted in slightly 0.0 different values for temperature and enthalpy, and are considered by many researchers to be -2.0 the most accurate values measured to date. 2.0 A DSC scan of a plutonium sample showed δ' − δ some unusual features of the phase transi- 0.0 tions. When heated from room temperature to δ − γ γ − β about 500 C, the phase transitions appeared -2.0 1.00 normal and well defined. However, when the -4.0 sample was cooled to room temperature, 0.00 things changed drastically. -6.0 In the scan, the delta-to-gamma cooling β − α 200 250 300 transition was no longer seen as a single dis- -8.0 ε − δ' tinct peak, but instead was seen as a set of -10.0 small, irregular peaks that occurred over a 100 200 300 400 500 broad temperature range. In addition, the gamma-beta transition was Temperature (Celcius) seen to be much broader than usual after cool- ing and suppressed by approximately 100 C calculate the volume fraction of material that below its heating onset. Los Alamos research- has a low solute content. ers are making detailed studies of this anoma- This volume fraction is a quantitative lous behavior. measure of how inhomogeneous the pluto- Delta-phase plutonium is desirable for use nium alloy is, which is important to know in many weapons systems because it is tough when manufacturing with plutonium alloys. and malleable. However, the delta phase isn’t DSC also may prove useful for observing stable at room temperature unless the pluto- homogenization in action. When an inhomoge- nium is alloyed with elements such as alumi- neous plutonium alloy containing aluminum, num, gallium, or indium. gallium, or indium is heated, solute begins to Because of differences in diffusion rates for diffuse and redistribute itself evenly through- these alloying elements in the high-temperature out the material. phases of plutonium, they can be unevenly dis- This solute redistribution process, called tributed in the plutonium. This inhomogeneous homogenization, releases heat that the DSC in- distribution of alloying elements is generally strument can measure. By observing changes undesirable, because regions of the material in the heat released during homogenization, that are low in alloy content will behave more researchers hope that the rate of homogeniza- like pure plutonium, while the regions high in tion can be quantified. solute content will be delta-stabilized. For a variety of reasons, however, this kind DSC scans of these inhomogeneous materials of measurement pushes the limits of sensitivity show phase transition peaks expected for pure and stability for even the most advanced DSC plutonium, and measurement of the heat re- instruments. Recent results suggest that leased during these transitions can be used to continued on page 15

Nuclear Materials Technology/Los Alamos National Laboratory 3 Actinide Research Quarterly

Fuel Form for ATW Researchers Investigate a Viable Fuel Form

This article was for Accelerator Transmutation of Waste contributed by NMT Division Assists R&D Effort in Advanced Nuclear Fuels Robert W. Margevicius (NMT-15). People in the United States currently get Those levels of discharge would require the about 20 percent of their power from the ap- construction and commission of a repository on proximately 100 operating commercial nuclear the scale of Yucca Mountain every three or four reactors in this country. years somewhere around the globe. There are more than 400 commercial Nearly all health-related risks arising from nuclear reactors supplying energy long-term disposal of spent are Spent around the world. is eco- attributable to about 1 percent of the fuel’s nuclear nomically competitive and has several content. This 1 percent primarily consists of fuel advantages over fossil-fuel-burning plutonium, neptunium, , and cu- plants, including no monoxide rium (called transuranic elements), and long- and nitrous emissions. lived isotopes of iodine and technetium However, among the disadvantages, created as products from the fission process the “waste product” from nuclear in power reactors. power—namely — When the transuranics are removed from represents the remaining signifi- discharged fuel destined for disposal, within a cant technical challenge to the period of several hundred years the toxic na- is processed nuclear-power industry. ture of the spent fuel drops below that of ura- through Los Alamos is assisting in an nium , which occurs naturally in Earth’s materials international effort to concentrate crust. In addition to a lower toxicity, removing separation the toxins from spent nuclear fuel the transuranics eliminates concerns related to into a special fuel form and to burn the need for centuries-long heat management that fuel. The project aims to develop within geologic environments. ways to extract the toxins and to make Removing neptunium, technetium, and the fuel. iodine renders negligible the possibility of radio- A number of methods for dealing with active materials penetrating into the biosphere spent nuclear fuel have been advanced. Two far in the future. Finally, removing plutonium prominent methods under consideration are negates any incentive for future intrusion into into direct disposal in a geological repository after a once- repositories driven by overt or covert recovery through burn and a waste-minimization ap- of material for . proach known as accelerator transmutation The potential payoff of ATW is huge. about 96%), of waste (ATW). Instead of requiring a geologic repository that Both disposal paths will require some must stay intact for one million years (about the type of repository. The repository for the first disposal time homo sapiens has existed), ATW requires a path will need to provide isolation for 10,000 to one repository that must last a few thousand years million years, while that of the second will need to (or as long as some of the buildings currently provide isolation for a few thousand years. on Earth—the Egyptian pyramids and the In the near future, approximately Colosseum in Rome, for example—have lasted). stable 87,000 tons of spent nuclear fuel In transmutation, the nucleus of an isotopes will exist in the United States undergoes a change to form either a new ele- and short-lived fisson products alone; the worldwide inventory ment or a new isotope. Some of the processes (about 3%) will be closer to 250,000 tons. that cause transmutation include natural Under the current disposal radioactive decay, , nuclear and scenario, 60,000 of the 87,000 tons in the fusion, and capture. plutonium, United States are slated for disposal at Transmutation uses , produced minor , Yucca Mountain in Nevada. However, either in a or in an accelerator- and long-lived current conservative projections esti- based system, to transmute the plutonium, long- fission products mate that by 2050 nearly one million lived fission products, and minor actinides. (about 1%). tons of spent fuel could exist throughout One current method of transmutation the world. under development involves a two-stage

4 Nuclear Materials Technology/Los Alamos National Laboratory 3rd quarter 2001

waste program. Spent nuclear fuel would be research into advanced nuclear fuels reprocessed to separate out the plutonium por- for many years. The research began in tion and some of the long-lived fission prod- the 1950s with the development of very ucts, as well as the minor actinides high temperature particle fuels for the (neptunium, americium, and ) and Rover space reactor program. Since other long-lived fission products. then, Los Alamos has continued to The plutonium-bearing portion could be be on the cutting edge of research Of the 1% plutonium, efficiently transmuted in a nuclear power reac- into nuclear fuel. tor, while the minor-actinide portion would be The most recent minor actinides, and transmuted in an accelerator-based system. major fuel program, long-lived fission products, The vital aspects to the accelerator system SP-100, was a develop- are the operating conditions—namely a sub- ment and production critical system with a fast neutron flux. This program for a space flux will change how transmutation occurs nuclear fuel. Uranium and the fission products generated. nitride was the There are a number of fuel options being obvious choice considered that could meet transmutation for the project the plutonium program objectives. because of its and some long-lived One fuel form could be chosen for favorable prop- fission products the minor actinides transmuting plutonium or plutonium with erties: a high and some other minor actinides in commercial power reactors melting point, long-lived fission (called Tier I transmutation). This fuel form excellent ther- can be products may be either an oxide pellet or a tri-isotropic mal conductiv- transmuted (TRISO) particle fuel and could be made with ity, high fissile in reactors. or without oxide. density, lower The fuel made without depleted uranium fission gas re- oxide will use another matrix diluent such as lease, and good radia- zirconium oxide because depleted uranium tion tolerance. are produces more plutonium while under irradia- Several years of more effectively tion (fertile) and zirconium is inert (nonfertile). development culmi- transmuted Another fuel form could be chosen for nated in the produc- in accelerator- transmutation of plutonium and minor ac- tion of a fully qualified core of driven systems. tinides in the accelerator-driven system (called advanced nuclear fuel. How- Tier II). ever, the choice for a fuel Tier II systems are fast (high-energy) form for accelerator trans- neutron systems and there are several potential mutation of waste has not fuel forms under consideration: alloy been decided. fuel segments, nitride or oxide pellets, or oxide While nitrides have a number of or nitride particle fuel in a metal matrix (com- favorable qualities, making them posite fuel). leading choices for the ATW fuel The diluent for each fuel form will likely be form, some yet-to-be-determined zirconium metal or the appropriate zirconium factors come into play, such as ceramic. Since much of the technology for the fuel temperature in the The energy commercial fuel already exists, most of the re- accelerator-driven system, the produced can search and development effort for transmuta- required fissile density, and the be used tion fuel is being directed toward the degree of fuel burnup. to generate accelerator-driven systems. Until a better determination of electricity in Nuclear Materials Technology (NMT) the operating conditions of the power grids. Division and its predecessors have conducted continued on page 15

Nuclear Materials Technology/Los Alamos National Laboratory 5 Actinide Research Quarterly

Editorial Student Programs are Vital to the Laboratory, the State, the Nation Exposing Students Early to the Excitement of Research May Lead More into Careers in Science and Engineering Los Alamos has a long history of hosting Student programs also are a key element of students who engage in our scientific and the employment pipeline at Los Alamos. Com- engineering research and development petition for the best science and engineering activities as well as the work that keeps the graduates is intense. Organizations that are Laboratory functioning—our business and the most successful in attracting recent gradu- operational efforts. ates frequently establish relationships with Students at all levels work here and students early in their education, both at the Allen Hartford, virtually every organization uses students in undergraduate and graduate levels. director of Science some capacity. During the past summer, we Many companies offer students internships and Technology Base employed 66 high school students, 930 under- and some support for their education. By be- (STB) Programs. graduate students (UGS), and 391 graduate re- coming familiar with an organization, stu- search assistants (GRA)—almost 1,400 dents develop a level of comfort and loyalty We focus part of this students. Los Alamos also employs about 275 that makes them more inclined to choose that issue of “The Actinide postdoctoral fellows and research associates. organization over those with which they are Research Quarterly” These programs represent a substantial less familiar. on students. Allen Hartford, director of commitment on the Laboratory’s part. The Our postdoctoral program is a prime the Science and costs are substantial, resources must be made example of this pattern. Over the past five and Technology Base available so that the students can accomplish one-half years, 32 percent of the Laboratory’s (STB) Programs their assigned work, and mentors must devote total technical staff-member hires has come office, which oversees time to ensure that the students have meaning- through the postdoctoral program. student programs at Los Alamos, leads off ful work and a positive learning experience. We must ensure that we develop with some thoughts So, why do we take on such a significant ongoing relationships with students who on students, mentors, undertaking each year? The reasons are many. demonstrate interest and promise in science and the importance Students bring fresh ideas and enthusiasm, and engineering careers. of students to the and challenge our employees, thereby keeping We also must develop ongoing and Laboratory as a whole. His editorial them on their toes. strategic relationships with prestigious col- is followed by stories Also, students make important contributions leges and universities most interested in highlighting three in meeting the Laboratory’s programmatic collaborating with our student programs. students in the goals. Clearly, they contribute to maintaining This means not only bringing students and Nuclear Materials an invigorating environment here. faculty here during the summers, but also Technology (NMT) Division: graduate Another reason we want to bring students bringing them here for extended periods dur- research assistant to the Laboratory is to encourage more young ing the academic year as part of an educa- Steven Alferink, people to choose careers in science and engi- tional and research experience. postdoc Andrew neering. We hope that by exposing students to We also must maintain contact with these Koehler, and former the challenges and excitement of research and students when they are back at school, to en- postdoc now staff member Susan development early in their studies, more of sure they are reminded that we value them Oldham. While their them will choose this path. and they view us as their employer of choice. areas of study vary There is ample evidence that the United Our student programs also need to be greatly—nuclear States is not producing an adequate supply of measured by their impact on the communities engineering and graduates with degrees in science and engineer- surrounding the Laboratory and New Mexico applied mathematics, social science, and ing to meet the country’s needs. For example, in general. We must be a good neighbor and chemistry—the three only five of every one hundred 24-year-olds in corporate citizen. As one of the largest em- had one thing in the United States have science and engineering ployers in the state, the Laboratory needs to common: dedicated degrees. Compare this with nine of one hundred provide career opportunities to the state’s resi- mentors. Read on for in South Korea and the United Kingdom, and dents. We need to be part of the effort to retain a glimpse of them, their research, and eight of one hundred in Germany. local talent in the state. their mentors.

6 Nuclear Materials Technology/Los Alamos National Laboratory 3rd quarter 2001

Stories by Meredith S. Coonley Photos by Mick Greenbank (NMT-16)

Student programs are one mechanism that However, the rewards are can aid in developing the wealth and diversity enormous for the Laboratory, of talent in New Mexico. and especially for the mentor While our student programs have been and the student. generally successful, there is room for im- On a personal note, I had provement. The Lab assesses the experiences the privilege of working this and concerns of the students through annual past summer with the Student surveys, and Director John Browne also meets Program Advisory Commit- annually with the students. tee, which suggested the con- In addition, this past year the Ombuds cept of a Student Program Office established a Student Program Distinguished Performance from which we have gathered further general Award. We were able to bring information about student issues. this to fruition this past sum- Among the primary concerns that have mer and made three awards— surfaced are misunderstandings about the na- one each to a high school ture of the work the student is to do, which co-op student, a UGS, and leads to unfulfilled expectations; the case of a GRA. the “disappearing mentor,” when the student Not only did these three doesn’t get sufficient interaction with the men- recipients make important and tor; and housing. impressive contributions to If I could do something about the latter, I’d the Laboratory during their probably be canonized. Nonetheless, we are stays, all 31 of the nominees working to find solutions to the perennial did exceptional work. I think Three of the best and problem of affordable student housing. this speaks highly of the positive impact the the brightest: Andrew To address the matter of well-defined work students have on our work. Koehler (standing), assignments, mentors and students are devel- Winners of the student awards were Susan Oldham, and oping somewhat formal agreements that spell Anabel Guerra, a high school co-op student Steven Alferink, all of out the assignment(s) in which the students with the Bioscience (B) Division Office; Apara the Nuclear Materials will be involved. This will avoid most of the Dave, a UGS in Materials Technology: Technology (NMT) situations where the students feel misled about Metallurgy (MST-6); and Gang Xie, a GRA in Division. To remain what their assignments will entail. B Division. a premier research We also are offering mentor training so that Science and Technology Base (STB) institution, Los Alamos mentors recognize the responsibilities they as- Programs, working with technical organiza- must aggressively sume when they hire a student and their obli- tions as well as the Human Resources (HR) identify the best talent and bring that talent gations to that student. Division, the Diversity Office (DVO), and the here, according to The student programs cannot succeed Office of Equal Opportunity (OEO), is commit- Allen Hartford, head without the commitment of the Laboratory’s ted to enhancing the quality of student pro- of Science and organizations and, more specifically, without grams, both from the perspective of the Technology Base the involvement of dedicated mentors. Laboratory and the students. (STB) Programs. Students will form opinions about the If we are to remain a premier research Laboratory based on whether they have an en- institution, the Laboratory must be aggressive riching experience here, and much of this will in identifying the best talent available and suc- depend on the nature of the work they become ceed in bringing that talent to the Laboratory. involved with and the quality of the mentoring Our student programs are important vehicles The opinions in this editorial are they receive. for cultivating that talent. ■ the author’s. They do not neces- —Allen Hartford sarily represent the opinions of We are well aware that being a mentor Los Alamos National Laboratory, requires additional effort, particularly when the University of California, the Department of Energy, or the the staff have so many other responsibilities. U.S. government.

Nuclear Materials Technology/Los Alamos National Laboratory 7 Actinide Research Quarterly

Focus on Students Nuclear Engineer Steven Alferink Improving on Existing Plutonium Isotopic Analysis Codes Steven Alferink first heard about Los The current analytical method for Alamos at a career fair at the University of determining the isotopic composition of Missouri-Rolla. “It sounded like a good oppor- plutonium in samples requires chemical tunity for me, so I jumped at it,” said Alferink. separations and analysis by thermal-ionization Since then, he has spent four summers at the . The technique is very accu- Lab, two as an undergraduate student (UGS) in rate and precise, but time-consuming, expen- Space and Remote Sensing Sciences (NIS-2) and sive, and requires destroying the sample. two as a graduate research assistant (GRA) in Nondestructive analysis techniques based 238Pu Science and Engineering (NMT-9). on gamma-ray have been devel- His initial work in NIS-2 focused on oped to measure large quantities (tens of grams satellite software programming, something to kilograms) of plutonium-239 or uranium for completely new to him at the time. The algo- safeguard and security purposes, but haven’t rithm he worked on his first summer is run- been tested and applied to small samples (mil- ning aboard the Multispectral Thermal Imager ligrams to nanograms). Steven Alferink satellite, which launched in 1999. Alferink’s project will extend the use of the His work in NMT-9 has included writing nondestructive analysis technique to analytical an instruction manual for the Solution In-Line applications to provide rapid (a few hours or Alpha Counter (SILAC), which provides alpha less) and accurate isotopic composition data activity measurements of aqueous solutions in for plutonium-238. glove boxes at the Plutonium Facility (TA-55). There is very little data on plutonium-238 He also created a document control because of the lack of a strong gamma-ray database that tracks more than 200 documents signature of plutonium-240 in plutonium-238 used in NMT-9, including safety procedures, materials. Alferink is using historic data from hazard control plans, training plans, drawings, the heat sources manufactured at Los Alamos equipment manuals, and lab notebooks. for the Cassini probe to Saturn as a basis for Alferink currently is working on a method to his algorithm. improve on existing plutonium isotopic analysis Alferink rates his student experience at Los computer codes for plutonium-238 samples. Alamos as very positive and credits his team The goal is to determine a correlation for leader and mentor in NMT-9, Amy Wong, with the weight percentages of plutonium-240 and making the past two summers so productive. -242 in plutonium-238 oxide materials. “She leads by example,” said Alferink, “and Alferink is hoping to implement this correla- she’s always there when I need her. She’s also tion into a new version of PC/FRAM to auto- very supportive of my working on the project matically determine the isotopic composition back in Rolla during the school year.” of plutonium-238 oxide materials. He enjoys the relaxed atmosphere of the PC/FRAM, developed by Safeguards group and the people he works with. Science and Technology (NIS-5), is an isotopic “I think I’m one of the few nonchemists in analysis software package used mainly for plu- the group, but they don’t hold that against tonium-239 and uranium materials. me,” he said. By analyzing gamma-ray spectra of a If there’s been a downside to Alferink’s sample, the PC/FRAM software helps re- student experience, it’s the time it has taken searchers determine nondestructively the per- to get a clearance (he’s still waiting), and the centage of weight composition of a sample. training required at the beginning of his as- If the isotopic composition of plutonium- signment (which he politely referred to as 238 samples can be determined accurately by “dry”). But he understands why the training is this nondestructive method, it could save time required: “After all, TA-55 is a nuclear facility.” and money, according to Alferink.

8 Nuclear Materials Technology/Los Alamos National Laboratory 3rd quarter 2001

Mentoring: An Investment in the Future

On the upside, Alferink didn’t experience Amy Wong, a radiochemist who joined some of the problems that may affect students: the Laboratory in 1994, believes in the im- inadequate housing, loneliness, and adjusting portance of mentoring. For Wong, to small-town life. He easily found housing his mentoring is as much about on-the-job first summers through the Lab’s Housing training as it is about developing an em- Office and the University of New Mexico- ployee and looking toward the future. Los Alamos. Last year’s Cerro Grande Fire “We need to invest time at the burned the apartment he was planning to rent, beginning, especially with new technicians so he lived in a motor home—along with his at TA-55, as well as girlfriend and three cats. with other new “I’m pretty much of a loner and Rolla is a hires, to make sure small town, so I was prepared for the small- they learn all the ness of Los Alamos, but I do miss green grass,” basics of safe opera- Alferink said. tions,” said Wong. Yet he admits luck was with him four years “In the longer term, ago when, on his first day of student orienta- we’re much better tion here, he met fellow GRA Beth Schlapper. off spending time The pair have been together ever since. early on helping With summer over, Alferink is back in Rolla them learn the right pursuing master’s degrees in nuclear engi- way to do things. neering and applied mathematics. He will “But mentoring continue his work on the plutonium isotopic is also about help- analysis project during the school year and ing an employee discover what direction to Amy Wong has hopes to return to Los Alamos next summer. take in his or her career. It’s an investment mentored Steven Schlapper, who earned a master’s degree in the future to help them develop their Alferink for the past two from UMR in in personal skills as well as their technical summers. He says she December 2000, is starting another master’s skills,” said Wong. “leads by example” and program in environmental engineering. Wong doesn’t have to look far for a role credits her with making his work experience so And both are settling into a new life model: her group leader, Liz Foltyn, won a productive. together—they got married July 28. ■ mentoring award this year from the Women’s Diversity Working Group for promoting the advancement of women in the workplace. More information about mentoring and tools to perform self-assessments are avail- Beth Schlapper and able at learning@lanl on the Training and Steven Alferink met on Development (HR-6) web site. The address the first day of student ■ orientation four years is www.hr.lanl.gov/TD. ago. They got married this summer.

Photo by Kevin Kessler, Another Perspective

Nuclear Materials Technology/Los Alamos National Laboratory 9 Actinide Research Quarterly

Focus on Students Social Scientist Andrew Koehler Creating an Integrated Facility-Program Model for the Modern Pit Facility Andrew Koehler isn’t in a scientific Koehler’s integrated facility-program discipline you’d expect to see in a student in model would bring together several estab- NuclearMaterials Technology (NMT) lished simulation techniques to create an inter- Division—he’s a social scientist. active, realistic simulation. But while his research is unusual for NMT Process modeling would be used to Division, what he’s proposing will help analyze fabrication activities to describe the the Laboratory’s nuclear weapons pro- flow of materials through the operations steps gram better plan for the future. performed at the Modern Pit Facility. As a postdoc in Pit Disassembly and Visualization and sound modeling, like Andrew Koehler Nuclear Fuels Technologies (NMT-15), that used in commercial entertainment soft- Koehler is looking at institutional issues, ware, would capture the experience of work- Laboratory organization, the Department of ing in the facility. Energy regulatory environment, and program Agent modeling, used in military execution to create an integrated facility-pro- simulations, would describe how information gram model for TA-55’s Modern Pit Facility. is managed inside the facility, and how regula- His goal is to come up with something the tors and other sources of requirements actu- Laboratory can use to make long-range strate- ally behave. gic plans to ensure performance, analyze regu- Koehler has worked at Los Alamos for four latory compliance issues, and train personnel. years. He spent several summers as a gradu- His simulation model will take into account ate research assistant, 18 months as a GRA in possible shifting regulatory and social man- NMT Division’s Office of Planning and dates, as well as changing government support Scheduling, and began his postdoctoral and shifting priorities. appointment in April. “You can look at it like enterprise modeling He attended the University of California- in the private sector,” said Koehler. “Take UPS, Berkeley, where he earned a bachelor of arts for example. It tracks how a package moves, degree in economics and a doctorate in public the errors that might occur, and the costs, as policy from the Goldman School of Public well as random events that may affect getting Policy. His dissertation, based on research per- the package where it should go. formed at Los Alamos, was titled “Design For “Los Alamos has a process system with lots a Hostile Environment: Technical of uncertainties, just like UPS, only the Lab’s Policymaking and System Creation.” system involves hazardous materials, waste Koehler calls K.C. Kim and Sophie Vigil of streams, lots of regulations, and changing gov- the NMT Division Office his guardian angels. ernment priorities,” said Koehler. “These “Sophie because she made dealing with many things change all the time, and they cost time of the complexities of the Lab easier; K.C. and money.” because he helped guide my research. He went above and beyond his duty in making my dissertation happen,” said Koehler. Koehler’s current advisor, Caroline “Cas” Mason, is helping in a similar way. “She’s very easygoing, but extremely protec- tive of my time and opportunities as a postdoc,” said Koehler.

10 Nuclear Materials Technology/Los Alamos National Laboratory 3rd quarter 2001

Mason, a chemist, was recently named team leader for Russian Programs–Plutonium Conversion Project in NMT-15. She has mentored numerous students, from summer students to postdocs, in her 26 years at the Lab. While every student has different needs, she describes her basic mentoring style as one of “benign neglect,” especially when it comes to postdocs. “My philosophy with postdocs is that they Andrew Koehler and can run their own lives,” said Mason. “They’ve his advisor Caroline received doctorates, which require a great deal “Cas” Mason discuss of self-motivation, and I don’t think they need Koehler’s integrated very close attention. facility-program “In Andrew’s case, if I attend a meeting model. Mason with him, it’s not because he needs the guid- describes her ance, it’s because I find his research interest- mentoring style as ing,” said Mason. “Of course, I try to be one of “benign available for him whenever he has questions neglect” when it or concerns.” comes to self- motivated postdocs On a scale of one to ten, Koehler rates his like Koehler. Lab experience as eight and one-half. “The Lab has opened up research opportunities I wouldn’t have had otherwise,” said Koehler. “Social scientists don’t often get to work at national laboratories.” As to life in the town of Los Alamos, Koehler admits it’s “unlike any place I’ve lived before.” A native of the other LA—Los Angeles, he currently lives in Santa Fe with his wife, Rosemary Sallee. Koehler summed up his Los Alamos experience this way: “I see my research project as a way to pay the Lab back—to help it do what it does and do it more robustly. It’s a win- win situation.” ■

Nuclear Materials Technology/Los Alamos National Laboratory 11 Actinide Research Quarterly

Focus on Students Chemist Susan Oldham Conducting Basic Research in the Fundamental Chemistry of Actinide Elements As a postdoctoral chemist in Weapons postdoc. Schake believes that good mentoring Component Technology (NMT-5), Susan is a way for Los Alamos to attract and keep Oldham spent two years doing basic research in the best and the brightest, whether postdoc or the fundamental chemistry of actinide elements. staff member. Her research into organometallic complexes “I try to be hands-off and leave the postdoc of uranium, neptunium, and plutonium will free to do research,” said Schake, “but I would increase the understanding of these elements never turn anyone loose in PF-4. I’m much more and how their chemical behavior compares to hands-on in that area. Conduct of operations is other, more extensively studied, elements in very important in an organization like ours.” the . “Making these new complexes may spark interest in other scientists to take the research Susan Oldham to another level, which could result in new uses for these complexes or new ideas for mak- ing other new complexes,” said Oldham. One of the projects she was involved with was investigating actinide amido complexes to explore the electrophilic chemistry of the ac- tinide elements. These types of complexes are interesting to researchers partly because of their rich reaction chemistry, including poten- tial activation of molecular nitrogen. The work, in collaboration with researchers in Nuclear Materials Technology (NMT) and Chemistry (C) divisions, shows promising re- sults and has extended the library of actinide Susan Oldham works inside a glove box while her complexes. (For more on the research, see mentor, Ann Schake, looks on. A former postdoc “The Actinide Research Quarterly,” herself, Schake believes that good mentoring is a way for Los Alamos to attract and keep the best 4th Quarter, 2000.) talent, whether postdoc or staff member. Oldham also has participated in a project to synthesize extremely novel uranyl carbene Oldham appreciated Schake’s method of complexes. These complexes represent the first mentoring. “She didn’t try to control my re- examples of actinyl-to-carbon bonds and sug- search, but she was always there to answer gest an unexpectedly rich diversity in actinide questions, help me understand Lab bureau- structure and bonding. cracy, and discuss ideas,” said Oldham. “She This project was also in collaboration with gave me ideas and suggestions and let me researchers from NMT and C divisions. explore on my own.” Oldham’s mentor was Ann Schake of Oldham graduated from Bowdoin College, NMT-5, an inorganic chemist who started her a small liberal arts college in Maine, in 1994 career at the Laboratory 11 years ago as a with a major in chemistry and a minor in math. She received a master’s in chemistry from the University of Washington in 1996 and a doctorate in in 1999 from the University of Rochester.

12 Nuclear Materials Technology/Los Alamos National Laboratory 3rd quarter 2001

First Annual ATOMICS Student Poster Session

She lives in White Rock with her husband, Students working in the Nuclear Warren, also a chemist and former postdoc, Materials Technology (NMT) Division had and now a staff member in Pit Disassembly the opportunity to meet with division staff and Nuclear Fuels Technologies (NMT-15). and discuss their summer research at the first (Warren is pictured at right with other partici- annual ATOMICS Safety Process Office stu- dent poster session held in July at TA-55. pants at the ATOMICS student poster session.) Students presented posters on a variety of With her postdoctoral appointment over, subjects, including chemical engineering ap- Oldham has accepted a staff member position plications, actinide chemistry, computer pro- with NMT-5’s plutonium casting team. Her gramming, and safety in a nuclear facility. priority and focus has shifted to providing technical support and guidance to the casting team. She will be involved in the casting of plutonium into shapes, and ensuring that the products meet specifications and the instru- ments used are correctly calibrated. But Schake’s mentoring will not stop because Oldham is no longer a postdoc. The two share an office in TA-55, where Schake will be on hand to guide Oldham as she learns the ropes of working in PF-4. “One of the things I’ve liked most about working here is that there are so many differ- ent people doing so many different things. It’s nice to be able to have all of those resources together,” said Oldham. “There are lots of In the top row, from left to right, are: Photo by Michelle Stump people studying actinide chemistry, but for (NMTDO) different reasons—stewardship, separation Mandy Cortez, Pit Disassembly and technology, weapons production.” Nuclear Fuels Technologies (NMT-15); Julie Fife, Isotope and A highlight of her postdoctoral appointment (C-INC); Crestina Vigil, NMT ATOMICS; was the opportunity to attend technical sympo- and Warren Oldham, NMT-15. In the front sia, especially those given by Nobel laureates. row, from left to right, are: Stephanie Lopez, “It’s a great experience for young scientists, and Weapons Component Technology (NMT-5); older scientists, too,” said Oldham. Dustin English, Actinide Chemistry “Being a postdoc in NMT was an interesting Research and Development (NMT-11); balance of basic research and working toward Lecroy Raynes, NMT-11; and Willie ■ NMT’s mission and goal,” said Oldham. Montoya, NMT-15. The mission of ATOMICS (Allowing Timely Observations Measures Increased Commitment to Safety) is to continuously improve the health and safety of the NMT Division workforce by reducing at-risk behav- iors through ongoing behavioral observations. Organizers are already planning next year’s poster session, and want to enlarge the event and encourage a more complete representation of students throughout the division. ■

Nuclear Materials Technology/Los Alamos National Laboratory 13 Actinide Research Quarterly

Newsmakers NMT-DO’s David L. Clark Named Laboratory Fellow David L. Clark has been selected by soluble polymeric chelators. The project Director John Browne as one of six new proposes a new approach to radioisotope de- Laboratory Fellows. livery that will enable users to efficiently use The honor is made yearly to technical staff isotopes that emit multiple alpha particles dur- members who sustain a high level of excellence ing their decay sequence. in programs important to the Laboratory’s mis- This work will increase the applicability of sion, make important scientific discoveries that alpha-emitting radioisotopes for therapy, par- lead to widespread use, or are recognized as ticularly for difficult-to-treat solid tumors. David L. Clark has leaders in their fields both within and outside Other applications of include cellular-level and been named a of the Laboratory. localized therapy, and enhanced diagnostic Laboratory Fellow. Only 2 percent of the Laboratory’s and imaging capabilities. current staff may hold the title of “Fellow” at any one time. Clark, a member of the Nuclear Materials Technology Division Office (NMT-DO), was α named for his work in the structural inorganic 225Ac 221Fr ~100 µm ~80 nm and environmental chemistries of the actinides and his stewardship of the Seaborg Institute. He is recognized internationally for his

efforts to bring state-of-the-art molecular sci- Polymeric chelator with multiple binding sites ence concepts in structural characterization and theory of inorganic chemistry to the chem- istry of the actinide elements. NMT Division Becomes Clark has been involved in the development Part of New Directorate of a new research field known as molecular en- In an effort to make the Laboratory a more vironmental science, where molecular level un- unified, customer-focused organization, derstanding is used to unravel the fate and Director John Browne has realigned divisions transport of actinide in the environment. into new directorates. Nuclear Materials Therapy Research Technology (NMT) and Engineering Sciences and Applications (ESA) divisions comprise Receives LDRD Funding the new Weapons Engineering and A project to develop a new class of Manufacturing Directorate. radioisotope delivery systems for high-dose Richard Mah has been named associate localized cancer therapy has received director. Louis Salazar and Van Bynum have Laboratory Directed Research and Develop- been appointed principal deputy and deputy ment (LDRD) funding under the exploratory for pit manufacturing, respectively. As associ- research category. The project, Polymeric ate director, Mah will be a member of Chelators for Radioisotope Delivery Systems, Browne’s new senior executive team. ■ will be led by Mary Barr of Actinide Chemistry Research and Development (NMT-11). Co-investigators on the proposal were Editor’s note: The caption on Page 2 of the last Louis (Pete) Silks and Robert Atcher of the issue was incorrect. The photograph was a view Leo Szilard Resource (B-3), and Kent Abney, inside the chamber of a scanning electron micro- scope, not an ultrahigh-vacuum Auger spectrom- who was with Isotope and Nuclear Chemistry eter/energy loss spectroscopy instrument. (C-INC). Abney now is with Actinide Process Chemistry (NMT-2). The new class of radioisotope delivery systems will be based on amorphous, water-

14 Nuclear Materials Technology/Los Alamos National Laboratory 3rd quarter 2001

Improved differential scanning Improved Differential . . . calorimeters continued from page 3 dislocations, and voids , all caused by be- the heat of solute redistribution can be ing knocked into or out of sites that they do not measured, but it remains to be seen how accu- normally occupy. When a -damaged rate this measurement is. material is heated, it eventually reaches a tem- Another area where DSC has proven to be a perature where its constituent atoms can move useful tool is in making a rough measurement of freely enough to repair this internal damage. the extent of internal damage in old plutonium. The process of self-repair, called annealing, Plutonium is an alpha-emitting radionuclide releases a quantity of heat that can be mea- and is continually being damaged uniformly sured by DSC. While the measurement of the throughout its bulk because of recoil from the heat does not give specific information about uranium daughter product of the alpha- the type of damage present in the material, it emission events. This damage accumulates does give a good indication of the total amount over time, and its exact nature is key to under- of annealable damage present. standing the aging effects that may occur in Researchers are making measurements of the nuclear weapons stockpile. this type on stockpile plutonium materials of Self-irradiation damage comes in a variety various ages. ■ of forms, such as vacancies, interstitials,

Fuel Form . . . continued from page 5 The near-term goal of the fuel development Fuel Form accelerator is made, the best fuel type cannot effort is the insertion of a final (or near-final) for ATW be decided upon. Therefore, the research and fuel type into the Phenix Facility in France development effort will consider the four fuel sometime after 2004. Exposure to Phenix’s fast types in parallel, including nitride, metal alloy, neutron spectrum will help determine a given oxide, and dispersion (ceramic particles in a fuel type’s ultimate performance. metal matrix). NMT Division will focus its ef- Many challenges to fully implementing forts on development of ceramic-based and ATW remain. They range from political (ad- dispersion fuels. dressing reprocessing of spent nuclear fuel) to The Advanced Accelerator Application social (public acceptance of nuclear technol- (AAA) Program—consisting of Accelerator ogy) to technical (fabricating fuel from very Production of (APT) and Accelerator radioactive minor actinides). Transmutation of Waste (ATW)—is truly a But the consequence of not pursuing ATW national and international effort. is significant because spent fuel buried in geo- While the program director, Edward Arthur, logical repositories will require safe contain- is headquartered at Los Alamos, many of the ment for tens of thousands of years. project leaders are located at other institutions. However, if ATW is implemented, the Los Alamos is working in close collabora- will be nearly complete, and tion with Argonne National Laboratory (East nuclear power can retain its position—and po- and West) to determine a viable fuel form. tentially increase its appeal—as a means for Experimental fuel pellets fabricated at Los power production for many years to come. ■ Alamos and metal segments fabricated at Argonne are scheduled to be inserted into the For more on spent nuclear fuel reprocessing, Advanced Test Reactor (a thermal-spectrum re- see “The Actinide Research Quarterly,” search reactor at Argonne-West) late next summer. 2nd and 3rd Quarter, 2000. Internationally, the U.S. program is interacting with the European and Japanese transmutation programs.

Nuclear Materials Technology/Los Alamos National Laboratory 15 Actinide Research Quarterly

Newsmakers

The conference, third in a series, will provide an international forum for presentation and discussion of current PLUTONIUM research on physical and chemical properties FUTURES— and environmental interactions of plutonium THE SCIENCE and other actinide 2003 elements.

For more information, visit the Plutonium Futures—The Science homepage at Albuquerque, New Mexico, USA www.lanl.gov/pu2003.

A Four-Day Topical Conference on Plutonium and Actinides

July 6Ð10, 2003

Nuclear Materials Technology Division Mail Stop E500 Los Alamos National Laboratory Los Alamos, New Mexico 87545 Phone (505) 667-2556/Fax (505) 667-7966 LALP-01-121

NMT Division Director: Timothy George Chief Scientist: Kyu C. Kim Writer/Editor: Meredith S. Coonley Design and Production: Susan L. Carlson Printing Coordination: Lupe Archuleta

The Actinide Research Quarterly highlights recent achievements and ongoing programs of the Nuclear Materials Technology (NMT) Division. We welcome your suggestions and contributions. If you have comments, suggestions, or contributions, you may contact us by phone, mail, or e-mail ([email protected]). ARQ also can be read on the World Wide Web at: http://www.lanl.gov/orgs/nmt/ nmtdo/AQarchive/AQhome/AQhome.html.

Los Alamos National Laboratory, an affirmative action/equal opportunity employer, is operated by the University of California for the U.S. Department of Energy under contract W-7405-ENG-36. All company names, logos, and products mentioned herein are trademarks of their respective companies. Reference to any specific company or product is not to be construed as an endorsement of said company or product by the Regents of the University of California, the United States Government, the U.S. Department of Energy, nor any of their employees. Los Alamos National Laboratory strongly supports academic freedom and a researcher’s right to publish; as an institution, however, the Laboratory does not endorse the viewpoint of a publication or guarantee its technical correctness.

16 Nuclear Materials Technology/Los Alamos National Laboratory