2nd/3rd quarter 2000 The Actinide Research Los Alamos ... · and economic growth, the same effi-ciency of energy sources, and the same percentage of carbon-based fuels. Under business-as-usual,

1Nuclear Materials Research and Technology/ Los Alamos National Laboratory

Los Alamos National LaboratoryThe Actinide Research

a U.S. Department of Energy LaboratoryQuarterly

In This Issue

1Plutonium ConferenceIlluminates Aspects of

Unique Element

6Conference Banquet

Speaker OpposesNuclear Fuel

Reprocessing

8 Editorial:

Plutonium ScienceChallenges Future

Researchers

10Speaker Urges:

Eliminate NuclearWeapons and Nuclear

Fuel Reprocessing

13Researchers Addressthe Interrelationship

of Hydrolysis andPressure in Stored Pu

16Interactions of Pu with

DesferrioxamineSiderophores Can

Affect Bioavailabilityand Mobility

19Publications

20NewsMakers

2nd/3rd quarter 2000

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

Plutonium Conference IlluminatesAspects of Unique Element

Plutonium Futures—The Science

The second international “Plutonium Futures—The Science”conference opened Sunday afternoon, July 9, at La Fonda, on the his-toric Santa Fe plaza. Sponsored by the Laboratory in cooperation withthe American Nuclear Society, the three-and-a-half-day conference,plus tutorial, drew 410 participants from 15 countries and includedsome 50 post-doctoral researchers and graduate and undergraduatestudents, not including those from the Laboratory. Attendance formany of these students was sponsored by the conference.

The conference provided those in attendance with an opportunityto participate in an assessment of the current understanding of pluto-nium and actinide sciences and to focus on the science needed to solveimportant national and international issues associated with plutonium.It placed an emphasis on involving students who will carry on the taskof solving nuclear issues into the next century. The conference pursuedthe science of plutonium with noted plenary speakers discussing policyand management issues, followed by 35 selected oral presentationsgiven by speakers from a dozen countries and 140 posters addressingtopics in materials science and nuclear fuels, condensed matter physics,

2 Nuclear Materials Research and Technology/ Los Alamos National Laboratory

Actinide Research Quarterly

Plutonium Conference IlluminatesAspects of Unique Element (continued)

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actinides and processing, actinides in theenvironment, and actinides and transuranicwastes.

In Sunday’s preconference tutorialsession, David Clark, head of the Glenn T.Seaborg Institute for Transactinium Science atLos Alamos, voiced a theme woven through-out the conference, “Plutonium is absolutelyunique among all of the elements. After some50 years of research into the characteristics ofPlutonium, something as simple as the num-ber of phases the element can take and thephase diagram of Pu-Ga alloy are still unde-termined.” Other speakers in the overflow tu-torial session gave the history of the discoveryand studies of plutonium, Pu surface science,and studies of Pu oxides.

Plenary speakers on the opening day ofthe conference highlighted both scientific andinternational policy discussions of plutonium.Darleane Hoffman, UC Berkeley, reprised thetalk she gave as a recipient of the covetedPriestly Medal, highest award of the AmericanChemical Society for lifetime achievement, inApril this year. She talked about the continu-ing search for super-heavy elements.

Nikolai Ponomarev-Stepnoi of the RussianKurchatov Institute showed a video with En-glish narration on past, present, and futureuses of plutonium in Russia. His vision of the

future is “clear,cloudless skies with-out any greenhouseeffects” through theuse of advanced,nuclear-fueled ther-mal reactors forpower generation.

Thomas Cochranof the Natural Re-sources DefenseCouncil says his vi-sion is for “completedisarmament understrict and effectiveinternational con-

trols” with specific suggestions for bilateral ef-forts to do so. He believes such efforts shouldresult in a complete ban on weapons-usablematerials, moving them into unclassified formsfor long-term storage. Breaking from his fellowenvironmentalists, he does favor radioactivesources for use in space.



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Leo Brewer, UC Berkeley professor(Emeritus), challenges scientists to be innova-tive and to be willing to follow in whateverdirection their research takes them. Usinghimself as an example, he says, “My ideasare rejected, then ten years later my ideas are

confirmed and I get an award!” In anothertheme that echoed throughout the conference,Brewer challenged the audience to educate thepublic on radioactivity. “Use the example ofpotassium,” he urged. “Tell them if they didn’tget their potassium, they would die.”

Vladimir Onoufriev of the InternationalAtomic Energy Agency gave his vision fornuclear power of the future. “In the longterm,” he said, “we will see fast reactors usingtechnologies specifi-cally designed forMOX (mixed-oxide)fuels.” However, hefeels that if pluto-nium fuels do notbecome commer-cially attractive toutilities, plutoniumand other actinideswill still be repro-cessed in interna-tional fuel-cycle cen-ters for future needs.In any case, he predicts that advanced pro-cesses will make nuclear reactors low-cost andenvironmentally safe.

Former Lab Director Siegfried Hecker re-turned to the question of why plutonium issuch an unusual metal. “It is the f electrons,and specific aspects of the f electrons thatmake plutonium so peculiar from ametallurgist’s point of view,” he stated. Heechoed the tutorial session as he talked aboutplutonium’s thermal instability, pressure in-stability, and unexpected alloying behavior.

“Some see plutoniumas the ‘scourge ofmankind,’” he con-cluded, “Others seeit as the savior ofmankind. But whatit is is the most fasci-nating element weknow of.”



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Plutonium Conference IlluminatesAspects of Unique Element (continued)

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A spirited exchange of views on thesetopics continued in the evening panel discus-sion. There was a broad consensus on thepanel that plutonium separated from weap-ons should be rapidly moved toward thespent fuel standard (SFS), where reuse, espe-cially clandestine reuse, is difficult. The activedebate centered on the means of achieving theSFS and the role of nuclear power, especiallyplutonium, in meeting future global energyneeds. Finally, political and technical state-ments were braided together by the panelistsin answer to audience questions. Those panel-ists who see nuclear power generation in thefuture avowed that science and technologywill provide technical solutions to thepolitical questions.

The conference poster session provided asurprisingly large and diverse collection ofpapers from many countries. Awards weregiven to the ten best posters. The articles fol-lowing in this issue of Actinide ResearchQuarterly are based on two of these posters.The award-winning posters may beseen on the conference Web site athttp://www.lanl.gov/pu2000.html .

Financial support for the conference wasprovided by the Associate Laboratory Direc-torate for Weapons Programs and the Associ-ate Laboratory Directorate for Threat Reduc-tion. The Office of Basic Energy Sciences/USDepartment of Energy sponsored student at-tendance at the conference. Plutonium-relatedexhibits were provided by Westinghouse

Savannah River Company, Argonne NationalLaboratory, Lovelace Respiratory ResearchInstitute, and Los Alamos NationalLaboratory.

Conference proceedings were distributedto all participants and are available from theAmerican Institute of Physics (AIP ConferenceProceedings 532). Participants also received apreview of the upcoming Los Alamos Scienceissue “Challenges in Plutonium Science,”(Number 26, 2000) on CD. Hard copies andCDs of the entire issue will be available bymid-October. People are welcome to requestcopies (see http://www.lanl.gov/worldview/science/lascience/). The confer-ence Web site including photos and the finalconference program will be maintained untilthe next conference, tentatively scheduled forsummer 2003. Comments and suggestions forthat conference are welcome.



Plutonium Futures—The Science

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Ann Mauzy, CIC-1contributed thisarticle, and MickGreenbank wasthe photographer.



Conference Banquet SpeakerOpposes Nuclear Fuel Reprocessing

The following is asummary of thetalk “PlutoniumNonproliferationand NuclearPower,” byJohn Holdren ,Teresa and JohnHeinz Professorof EnvironmentalPolicy, John F.Kennedy Schoolof Government,Harvard.

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Options for Dispositionof “Excess” Weapons Pu

“The worldwide supply of weapons pluto-nium is about 250 tons, including that declared‘excess,’” declared John Holdren, banquetspeaker for the second international “Pluto-nium Futures—The Science” conference. Hecontinued, “Reactor plutonium suppliesamount to about 1,120 tons. The options fordisposition of these materials are to store themin different forms, burn them in existing reac-tors, save them for advanced reactors of thefuture, or immobilize them for disposal inwaste repositories. There may be other optionsas well.”

Holdren described how a committee of theNational Academy of Sciences evaluated theoptions for weapons plutonium. Holdren was amember of this committee. The committee re-port was published in two volumes in 1994 and1995 and concluded that “excess” plutonium

poses a danger to theUS and the world.“Well-guarded stor-age is not sufficient,”Holdren added; “ap-propriate barriers areneeded as well. Thematerial must bemade as difficult asreactor plutonium toreuse; that is, it needsto meet the spent fuelstandard (SFS).” Thecommittee also con-cluded that the diffi-cult disposition

decisions need to be made now, before othernuclear energy issues are solved.

The two least problematical dispositionmethods to use in meeting the SFS, the commit-tee pointed out, are to immobilize the materialsin glass logs or to use them as MOX (mixed-oxide) fuels, once-through in reactors. Thecommittee recommended that this option bepursued in parallel by both U.S. and Russia incooperation. Holdren noted that a U.S./Rus-sian commission came to the same conclusion,but with four nonproliferation conditions: ajoint agreement is needed, international fund-ing is needed, the material should be protectedas reprocessed plutonium, and we shouldnot delay.

Where Are We Going?Holdren said the energy supply message is

this: at the end of the twentieth century, theworld is still dependent on fossil fuels in spiteof the work done onrenewable energysources. “Business-as-usual” can be definedas the same rate ofpopulation growthand economicgrowth, the same effi-ciency of energysources, and the samepercentage of carbon-based fuels. Underbusiness-as-usual, theamount of CO2 in theenvironment willtriple.

Holdren statedthat the world is notrunning out of energy. “The essence of the en-ergy problem,” he explained, “is that the worldis running out of cheap oil, the environmentneeded to absorb the impacts of business-as-usual, and the tolerance for inequity of whohas/doesn’t have energy and who is/is notproducing waste. The world is also runningout of money for better options, the time for asmooth transition to non-carbon-based formsof energy, and the leadership to do what isrequired.”

Environmental issues surrounding the con-tinued use of carbon-based energy are the mostintractable, Holdren noted. The most danger-ous of these is global climate change, which isinvolved in 80% of present energy production.Developing countries are becoming the largestpart of the problem.

As a consequence of business-as-usual,Holdren predicted, the earth will becomewarmer, as much as 5% warmer. Sea levels willrise, displacing people all over the world wholive in coastal areas. There may be some un-pleasant surprises as well: disease, storms,shifts in ocean currents, and more. If the worldgoes beyond double the preindustrial concen-trations of air pollutants, these consequencesmay be expected. “With business-as-usual,”Holdren warned, “we will triple these concen-trations or more.



Haldron 1865

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Holdren expressed the need for renew-able, non-carbon-emitting sources and solu-tions to the worldwide energy generationneeds, and said nuclear fission or fusionsources can help fill these needs. “Capturingemissions from current sources will help aswell,” he added.

Can the Contribution of NuclearPower Be Expanded?

Holdren listed the remaining obstacles tothe expansion of nuclear energy: reactorsafety, waste management that is acceptable tothe public, and minimized linkage to nuclearweapons. “The latter is the most important,”he said. “While many include economics as anobstacle,” he predicted, “in the long term fossilfuels will be more expensive, equal to the costsof nuclear generation. So economics is reallynot an issue.”

Holdren calculates that if nuclear powerwere to go from the present one-sixth of totalenergy production to a one-third share,nuclear plants would have to be ten timesmore numerous than they now are. But hepredicts that by 2050 fission power may bephased/phasing out. He suggested that

options that may be viable in the future in-clude “once-through” nuclear fuel, whichyields high power generation and low recy-cling, or some method that yields high genera-

tion and high recycling such as advancedheavy metal reactors (AHMRs).

“Waste management complexities interactwith other complexities such as threats,”Holdren added. Threats he listed include thediversion of materials from power to weapons,theft of materials, and a loss of confidence inthe prevention of diversion or theft.

“In the short term, 10 years or so, thematerials that pose the threats are separatedmilitary plutonium, civilian plutonium, andhighly enriched uranium,” Holdrenenumerated. “These should be put away inSFS forms. Reprocessing and recycling nuclearmaterials at this time make these threats morecredible, make proliferation worse, and aremore expensive than the once-through orAHMR options.”

Holdren concluded, “For the medium-long- and unimaginable-long terms it ispremature to assume that we can reprocess ortransmute nuclear materials, but researchshould continue. If we want to maximize ourchances of providing a larger percentage ofpower generation with nuclear fuel, we needto make it safer, more economical, and moreacceptable. Reprocessing will not accomplishthese goals.”



Plutonium Science ChallengesFuture Researchers

This editorialwas provided byS. S. Hecker ,senior fellow atthe Laboratory.Illustrationscourtesy of LosAlamos Sciencemagazine.

1500

Temperature (°C)

Liquid

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Ac Th Pa U Np Pu Am Cm

1000

500

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The International “Plutonium Futures: TheScience” Conference in Santa Fe in early Julywas a convincing testament to the resurgenceof interest in plutonium science. More than 400attendees from 15 countries gathered to dis-cuss advances and challenges in plutoniumchemistry and materials science. The techno-logical challenges stem from the applicationsof plutonium—principally stockpile steward-ship and nuclear power, and from dealingwith the problems left behind by those appli-cations—environmental concerns, waste dis-posal issues, and potential proliferationconcerns. The scientific challenges stem fromthe fact that plutonium is the most complexelement in the periodic table.

Plutonium is of interest because of the ex-traordinary nuclear properties of the isotopeplutonium-239. Extracting the energy of itsnucleus provides a “factor of millions” advan-tage in energy production or explosive power.However, electrons determine its chemical,physical, and mechanical properties and itsengineering behavior. In the metal, it takeslittle provocation to change its density by asmuch as 25 percent. It can be as brittle as glass

or as malleable asaluminum; it expandswhen it solidifies—much like waterfreezing to ice; itsshiny, silvery, freshlymachined surface willtarnish in minutes,producing nearly ev-ery color in the rain-bow. It is highlyreactive and a verystrong reducing agentwhen in solution,readily forming com-pounds and com-plexes duringchemical processesor in the environ-ment. It transmutesitself by radioactivedecay, causing dam-age to its crystalline

lattice and leaving behind helium, americium,uranium, and other impurities. It also dam-ages all materials or solutions in contact, mak-ing it difficult to store and difficult to predictits transport. No wonder its principal applica-tions are limited to those for which the “factorof millions” is crucial.

We have never fully understood the fun-damental reasons for the unusual propertiesof plutonium. We have learned just enoughabout its chemical behavior to allow us toseparate it from the reactor products and pu-rify and recover it from scrap, and enoughabout its metallurgical behavior to shape itand engineer it for its applications. The earlyquest for fundamental understanding sloweddown considerably in the 1980s and early1990s, but now interest has been revived fortwo principal reasons. First, the era of nonuclear testing ushered in by the end of thecold war places a premium on understandingplutonium better because we can no longer dothe proof tests that allowed us to bridge thegap between our understanding of physicsand actual weapon function. Second, we mustnow find more efficient and cost-effectivemethods to deal with the environmental prob-lems created during the cold war and to makecertain that we do not create additional prob-lems in the future. In addition we must pro-vide protection for fissile materials andcost-effective disposition of plutonium de-clared excess to the nuclear weapons pro-grams. Thus, we must resolve fundamentalquestions about the physics, chemistry, andmetallurgy of plutonium.

Much of the current work in the actinideswas reviewed in Santa Fe. The single most un-usual characteristic of plutonium is its instabil-ity. In the metal, it is extremely sensitive to theslightest changes in temperature, pressure, orchemistry. Small changes, in turn, producevery large changes in physical and mechanicalproperties. In solution, changes in oxidationstate, which occur readily through smallchanges in solution chemistry or even throughradiolysis, lead to a variety of molecular com-plexes, each with a characteristic solubilityand chemical reactivity. Recent electronic

Figure 1. Connected binary-phase diagram (tem-perature vs. composition) of the actinides. Suchdiagrams demonstrate the transition from typicalmetallic behavior at thorium to the enormouscomplexity at plutonium and back to typical metallicbehavior past americium. With little provocationplutonium will change its density by as much as 25percent. It can be as brittle as glass or as malleableas aluminum; it expands when it solidifies. Itsunusual behavior is just one of the challenges ofunderstanding plutonium.

Editorial



C377-4

.0

.5

.5

0

0 2 4 6pH

8 10 12 14

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PuO2CO3(aq) PuO2(OH2)2(aq)

PuO2OH(aq)

Pu(OH)4(aq)

PuO2(CO3)22−

PuO2(CO3)34−

Pu(III)Pu(IV)Pu(V)Pu(VI)Range of natural waters

PuO2F+

PuOH2+

PuO2CO3−

PuO2+

Groundwater

Ocean

Rain/streams

The opinions in thiseditorial are mine; theydo not necessarilyrepresent the opinionsof Los Alamos NationalLaboratory, the Univer-sity of California, theU.S. Department ofEnergy, or the U.S.Government.

Figure 2. The color of plutonium oxidation states.Each oxidation state, ranging from Pu(III) to Pu(VII),has a characteristic color in solution. Plutonium willoften change oxidation states in solution, making itsinteraction with the natural environment inordinatelycomplex.

Figure 3. Pourbaixdiagram for plutonium:another demonstrationof the complexity ofplutonium in theenvironment. This Ehvs. pH diagram iscalculated for plutoniumin water containinghydroxide, carbonate,and fluoride ions. Thered dots are triplepoints, where plutoniumcan exist in threedifferent oxidationstates. The range of Eh/pH values found innatural waters isbounded by the solidblack outline. Dashedlines define the area ofwater stability.

structure calculations provide valuable insightto demonstrate how the unusual properties ofplutonium result from the systematic variationin the bonding of the 5f electrons across theactinide series. By examining the trends acrossthe series, we find that the peculiarities of plu-tonium are not a single anomaly but the culmi-nation of a systematic trend of bondingbehavior of the 5f electrons. Plutonium sitsright at the knife-edge in the transitionbetween bonding or chemically active5f electrons and localized or chemicallyinert 5f electrons.

While the science of plutonium is thuscomplex and exciting to study of itself, wemust redouble our efforts to bring fundamen-tal knowledge to bear on the demanding set ofapplications we face this century. For example,to certify nuclear weapons without testing wemust develop a better understanding of agingeffects, particularly the effect of self-irradiationdamage on plutonium’s already notorious in-stability. Furthermore, although plutonium isa man-made element created an atom at a timein reactors, the world now has more than 200tonnes of plutonium in its military stockpilesand more than 1000 tonnes (800 tonnes arecontained in spent-fuel elements) in civilianinventories. Its protection from unauthorizeduse, its potential utilization as reactor fuel, orits geologic disposition represents not only agreat scientific challenge, but also a nationalsecurity imperative.

We also recognize that during the cold warsignificant quantities of plutonium and otherradioactive materials were released into theenvironment. In addition, civilian nuclearpower programs continue to create nuclearwaste waiting for an acceptable method ofdisposal. These problems represent one of themost challenging applications of modern chem-istry because of the inherent complexity of plu-tonium and the corresponding complexity ofthe natural environment.

To enhance our understanding of the fun-damental behavior of plutonium and to applythis knowledge to solving these challengingproblems, we must attract the next generationof scientists and engage the internationalscientific community. The Plutonium FuturesConference took an important step in thesedirections. Also, as Dave Clark pointed out in aprevious editorial, we must rekindle the educa-tional programs intransactinium science.To attract the nextgeneration of re-searchers and the aca-demic community,we must continue toinstill a spirit of scien-tific excitement thatwas so evident inSanta Fe.

The greatest chal-lenge, however, willbe to turn around thecrisis of confidencethat has developed inthe operation of thenation’s plutoniumfacilities during thepast decade. The inordinate difficulty in accom-plishing experimental plutonium work today,which underlies this crisis, is having a chillingeffect on the ability to recruit and retain thebest and the brightest. Our ability to operatenuclear facilities safely and successfully is ofutmost importance in regaining public confi-dence and attracting the next generation ofplutonium scientists.



Speaker Urges: Eliminate Nuclear Weaponsand Nuclear Fuel Reprocessing

This is a summary. The complete text maybe found on the Web at http://www.lanl.gov/pu2000.html

Beyond trace amounts in uranium oredeposits, plutonium is man-made; its exist-ence and quantities are determined by itsproduction and utilization since the 1940s.Plutonium has two major applications—as anuclear explosive material and as a nuclearreactor fuel—and one minor applicationwhere the isotope 238Pu is highly concentratedas a source material for radioisotope thermo-electric generators and heater units.

Today eight countries possess nuclearweapons—the United States, Russia, theUnited Kingdom, France, China, Israel, Indiaand Pakistan. The first five have signed theNuclear Nonproliferation Treaty (NNPT). Theparties have an obligation under Article VI ofthe NNPT:

“to pursue negotiations in good faithon effective measures relating to ces-sation of the nuclear arms race at anearly date and to nuclear disarma-ment, and on a treaty on general andcomplete disarmament under strictand effective international controls”

To meet this obligation they must under-take (1) political steps designed to reduce in-centives to acquire and accumulate nuclearweapons and threaten their use, and (2) tech-nical steps to eliminate existing arsenals andincrease the time it takes to reconstitute themor acquire new ones. With regard to the tech-nical measures, it is important to recognizethat our NNPT obligations are not limited tothe elimination of nuclear warheads them-selves. If a nation disassembles an arsenal ofnuclear warheads and stores the critical com-ponents, the effect is only to marginally in-crease the time it takes to reassemble and usethem. A more useful parameter for measuringprogress in achieving nuclear disarmamentis the availability of deliverable warheadsover time.

Thus, the parties must reduce the numberof nuclear warheads on launch-ready alert, ongenerated alert, in the active stockpile, in theinactive stockpile, and awaiting dismantle-ment. They must reduce the stockpile ofweapons-usable fissionable materials inweapon component form (e.g., pits), in strate-gic reserves, and in separated forms.

The lack of progress made by the U.S. andRussia in achieving meaningful reductions inmost of these categories is evidence that nei-ther country is making a good-faith effort tomeet its NNPT obligation under Article VI.

To meet its treaty obligation, the U.S.should take the following steps immediatelyand unilaterally:1. Stop specifically targeting Russia

and other countries with nuclearweapons. Under new guidance the U.S.should not target any country specificallybut create the capability to quickly con-struct contingency war plans if needed.

2. Take all U.S. land-based ICBMs off alert.3. Ratify the Comprehensive Test Ban

Treaty.4. Redirect and scale back the Stockpile

Stewardship and Management Programto focus on acquiring the capability toremanufacture existing, well tested de-signs to original specifications, as re-quired. The stewardship program shouldbe scaled back and limited to finding waysto maintain a set of well tested nuclear de-signs, without the emphasis on providingthe capability to develop and certify newnuclear weapons without testing.

5. Permanently close the Nevada Test Site.Negotiate with Russia the joint permanentclosure of NTS and Novaya Zemlya. Thiswould have the added benefit of makingthe Comprehensive Test Ban Treaty easierto verify and consequently easier to ratify.

In addition, the U.S. should seek the fol-lowing on a bilateral or multilateral basis:

6. Much deeper reductions in U.S. andRussian strategic arsenals.



continued on page 12

Thomas Cochranis associatedwith the NaturalResourcesDefenseCouncil, Inc.

7. The elimination of all non-strategicnuclear warheads, all reserve warheadsand all strategic reserves of fissilematerials.

8. Public declarations of all nuclear weaponand weapon-usable fissile material stock-piles and production histories, and coop-erative verification measures to confirmdata included in these declarations anddata exchanges.

9. More informal transparency measures.(demonstrate progress and fairness in ongoing arms reduction processes, buildconfidence that they are significant andunlikely to be reversed, reduce uncertain-ties in estimates of weapons and weap-ons materials). New security measuresproposed or recently imposed furtherhamper this effort.

10. Verified dismantlement of warheads andmonitored interim storage of their fissilematerial components.

11. Increased security and safe disposition ofexisting stocks of weapon-usable materi-als. The effort to place under InternationalAtomic Energy Agency safe guards fissilematerial inventories that have beendeclared to be in excess of national secu-rity needs by Russia and theU.S. is mov-ing ahead so slowly that the DOE lab-to-lab program must be counted as a failure.

12. Verified storage and disposition ofhighly enriched uranium (HEU) andplutonium declared to be in excess ofnational security needs. The program toassist Russia in disposing of its excessplutonium is unlikely to be successfulbecause its mission is to assist Russia inconverting excess plutonium into MOX tobe burned in existing reactors. Russia hasno MOX fabrication facility and cannotafford one, and no country has indicatedany willingness to pay. The Russian pluto-nium disposition effort should be refo-cused on converting plutonium pits tounclassified shapes and placing the effortunder bilateral and ultimately interna-tional safeguards.

13. Assist in downsizing Russia’s nuclearweapons complex and provide alterna-tive employment opportunities forworkers in Russia’s nuclear weaponcomplex. A potential source of newadditional revenues for several of theseinitiatives is the NonProliferation Trust,Inc. (NPT, Inc.) proposal, with which I aminvolved. This nongovernment initiativehas the potential to raise $15 billion inrevenues, of which over $11.5 billion willbe allocated to a variety of worthy projectsin Russia. The revenues would be raisedproviding spent fuel management servicesin Russian for 10,000 tonnes of foreign(non-Russian and non-U.S.) spent fuel.Western companies would build andoperate in Russia an interim, dry-caskspent fuel storage facility licensed by

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Speaker Urges: Eliminate Nuclear Weaponsand Nuclear Fuel Reprocessing (continued)

GAN, the Russian licensing authority, thatwould meet the technical licensing criteriaof the Nuclear Regulatory Commission.

Under the current NNPT proposal plan$2.3 billion of the revenues is allocated forthe construction of a geologic repositoryfor the foreign spent fuel in addition toRussian spent fuel and high-level radioac-tive waste. An additional $1.5 billion isallocated to fissile material security, $2billion for alternative employment oppor-tunities for workers in the Russian nuclearweapons complex, $3 billion for environ-mental cleanup, $0.5 billion for regionaleconomic development, and $2.25 billionfor humanitarian causes in Russia.

In the late 1960s the Atomic Energy Com-mission was predicting that increased use ofnuclear power would lead to reductions inpower plant costs and scarcity and increasedcosts of uranium, thus making plutonium re-cycling and fast breeder reactors economical.These claims have proven to be false. Never-theless, many countries adopted the closedfuel cycle—plutonium separation and recy-cling—in preference to direct disposal of spentfuel. As a consequence global inventories ofweapon-usable plutonium in civil stockpilesnow exceed plutonium inventories in militaryprograms, and the civil stockpiles continue togrow largely as a consequence of commercialreprocessing contracts made years ago.

Today it is abundantly clear that fastbreeder reactors and plutonium recycling inthermal reactors is uneconomical and will re-main so for the foreseeable future. The com-mercial use of plutonium in most countries ison the decline.

The concept of accelerator transmutationof waste (ATW) has been promoted as ameans of reducing the long-term risks associ-ated with geological disposal of high-level ra-dioactive waste. A recent DOE sponsored“roadmap” of the ATW concept indicates thatthis technology will be prohibitively expen-

sive. More importantly, no case has been madeto date that (1) the potential lives saved by re-ducing the transuranic and other isotopes go-ing into a geologic repository will exceed thepotential lives lost resulting from the imple-mentation of an ATW program, (2) the cost ofimplementing an ATW program is worth thebenefits, (3) greater benefits cannot beachieved at less cost by selecting an alternativerepository site and technology, (4) the nonpro-liferation benefits of an ATW program arepositive, or (5) that an ATW program can beimplemented by private industry.

So long as the global norm permits nationsto separate and stockpile large inventories ofweapon-useable fissile materials ostensibly forpeaceful purposes, there is little hope that thenuclear weapons states will be willing to moveto small nuclear weapon stockpiles. Since plu-tonium recycling is uneconomical and unnec-essary for energy independence or wastemanagement, the preferred course from a non-proliferation prospective is a complete globalban on commercial use of weapon-usable fis-sile material.

The DOE has supplied 44 radioisotopethermoelectric generators (RTGs), each con-taining kilogram quantities of 238Pu, and 240Puradioisotope heater units (RHUs), each con-taining grain quantities of 238Pu, on 26 spacemissions since 1961. Unless and until a morebenign reliable energy source can be found, itwill be necessary to continue to use 238Pusources for some deep space missions.

We have an obligation to the internationalcommunity to eliminate nuclear weapons andconvert existing stocks of separated plutoniuminto a form that is no more attractive as asource of weapon material than spent nuclearreactor fuel as a source of plutonium for weap-ons. There is no economic, environmental, ornonproliferation utility in separating addi-tional plutonium from spent fuel, at least notin the foreseeable future. 238Pu has limited util-ity in small quantities for deep space missions.In sum, plutonium has a long half-life, but ex-cept for deep space missions, it has no future.



Researchers Address the Interrelationshipof Hydrolysis and Pressure in Stored Pu

This article wascontributed byLuis Morales,NMT-16.

Figure 1. To provide astronger technical basisfor the new DOEplutonium stabilizationstandard for storage,NMT-16 researchersmeasured recombina-tion rates of hydrogen/oxygen mixtures incontact with pure andimpure plutoniumoxides.

The U.S. Department of Energy/Environ-mental Management (DOE/EM) is responsiblefor the management and long-term dispositionof a variety of materials located at Rocky FlatsEnvironmental Technology Site, Hanford, Sa-vannah River, and other DOE sites. The newplutonium storage standard, set to replaceDOE 3013, requires thermal stabilization of thematerials before they are packaged for storage.The Pu content of those materials can varyfrom ~86 weight percent, (essentially purePuO2), down to ~30 weight percent. With sucha range of compositions, plutonium dioxidecan be in contact with a variety of other mate-rials. Typically, these “impurites” includealkali metal chlorides, MgO, MgCl2, CaCl2,Fe2O3, and other materials that are not wellcharacterized. In addition, these solid mixturesare in contact with the gas phase under whichthe materials were packaged; the moisturecontent may not be known or well controlled.The new plutonium stabilization standarddoes not set acceptable glove box moisturelevels nor does it prescribe the time durationbetween calcination and packaging.

The 3013 standard contains an equationthat predicts the total pressure buildup in thecan over the anticipated storage time of fiftyyears. This equation was meant to model aworst-case scenario to insure pressures wouldnot exceed the strength of the container at theend of 50 years. As a result, concerns aboutpressure generation in the storage cans, bothabsolute values and rates, have been raisedwith regard to rupture and dispersal of nuclearmaterials. Similar issues have been raisedabout the transportation of these materialsaround the complex.

The technical basis for the pressure equa-tion given in the 3013 standard has not beenfully established. The pressure equation con-tains two major assumptions, (1) that hydro-gen and oxygen generated from radiolysis oforganic materials do not react to form waterand (2) that the oxygen generated by radioly-sis reacts with the oxide material and does notcontribute to the pressure in the container.With regard to the first assumption, if the for-mation of water from hydrogen and oxygen issignificant, then the calculated pressureswould be dramatically reduced. The formationof water is thermodynamically favored (morestable) over the splitting of water into hydro-gen and oxygen. In addition, the corporateknowledge from shelf-life programs aroundthe complex is that most containers do notshow signs of extreme pressurization.

In order to provide a stronger technicalbasis for the standard, we measured therecombination ratesof hydrogen/oxygenmixtures in contactwith pure and im-pure plutonium ox-ides. The goal ofthese experimentswas to determinewhether the rate ofrecombination isfaster than the rate ofwater radiolysis un-der controlled condi-tions. We used acalibrated pressure-volume-temperatureapparatus to measurethe recombinationrates, in a fixed vol-ume, as a gas mixturewas brought intocontact with oxidepowders whose tem-peratures rangedfrom 50oC to 300oC.

B1958-25



Researchers Address the Interrelationshipof Hydrolysis and Pressure in Stored Pu (continued)

These conditions were selected in order tobracket the temperature conditions expectedin a typical storage can. The gas mixture usedin these studies was composed of 2% hydro-gen, 19% oxygen, and 79% nitrogen. This 2%H2/air mixture encompasses scenarios inwhich actual storage cans were sealed in air,and over time various amounts of hydrogenare formed. This gas composition is below theexplosion limit.

The recombination of hydrogen and oxy-gen has been studied over the 50oC–250oCtemperature range in a 2% H2/air mixture.We obtained pressure-time curves and massspectrometric results for pure and impureplutonium oxides exposed to the gas mixture.The pure oxide was obtained from oxidationof alpha metal. The impure oxide was ob-tained through the Defense Nuclear FacilitiesSafety Board 94-1 R&D program’s MaterialsIdentification and Surveillance project andselected for its low plutonium content, 29weight percent, and its high chloride content.Analysis by x-ray powder diffraction showsthat the impure oxide is a mixture of pluto-nium dioxide, sodium chloride and potassiumchloride. (These materials contain galium inamounts undetectable by x-ray diffraction.)

The measured kinetic data, which consistof monitoring the total system pressure as afunction of time, were collected for the pureand impure oxide samples. These kinetic datashow that the rate of the pressure drop at100oC, 200oC, and 300oC for the pure oxide areequal based on the initial slopes of the pres-sure-time curves. Only the data collected at50oC show deviation from this behavior. Thedata for the 100oC run for the pure oxideclearly show a sharp break in the slope ap-proximately 100 minutes into the experiment.The pressure-time curves for the impure ox-ide experiments yield rates that are lowerthan those for the pure oxide counterparts.

Surface effects were investigated. The pureoxide, without any pretreatment, was allowedto react with the starting gas mixture. Whenthat phase of the experiment was complete,that same sample was then baked at 350oC un-der dynamic vacuum for 24 hours and thenallowed to react with the starting gas mixtureagain. Treating the sample by heating undervacuum increased the initial slope of the pres-sure-time curve by approximately a factor offour. Long-term experiments were also con-ducted on the pure oxide. After an initial,rapid pressure drop, the total pressure overthe pure oxide sample remains constant out to20 days.

In each experiment, the total pressure de-creased rapidly after the reactants were com-bined. The mass spectrometric results show anoverall depletion of stoichiometric amounts ofhydrogen and oxygen. The mass balances forthe mass spectrometric results are in excellentagreement with the assertion that hydrogenand oxygen recombine quickly to form water.The kinetic results indicate that the surface ofthe plutonium oxide powder plays a role in therecombination of hydrogen and oxygen. Thedata collected at 200oC before and after thethermal/vacuum treatment show a markeddifference in the pressure-time curves andtherefore in the rate of recombination. This dif-ference is a clear indication of surface effects.In addition, the abrupt change in the slope ofthe pressure-time curve and therefore the ratesof recombination at 100oC suggest that the sur-face of the oxide plays a role in the recombina-tion of hydrogen and oxygen. For those datathe slope, and hence the rate, of the pressure-time curve changes abruptly within 100 min-utes. In contrast, the data collected at 200oCand 300oC show a smooth decrease in the pres-sure with time out to approximately 800 min-utes when essentially all the hydrogen hadbeen depleted.



Above 100oC, the reaction is second-orderoverall. At and below 100oC, the process maybe third- or fourth-order. It is important tonote that the change in the reaction orderacross the 100oC temperature boundary is sig-nificant. The results of the long-term experi-ments indicate that steady-state gascompositions are reached, suggesting that therates of recombination and water radiolysisbecome equal under these experimental con-ditions.

These data show that when this gas mix-ture is exposed to pure plutonium oxideheated above 100oC, the recombination rate isdramatically faster than the radiolysis of wa-ter initially. Above 100oC enough thermal en-ergy is provided to remove water orhydroxide and to maintain a larger fraction ofthe active sites available for catalysis. Below100oC, the recombination rate seems to begoverned by the number of available sites andthe rate at which they are filled. These obser-vations are more consistent with a chemicalreaction of H2 and O2 at catalytic sites on theplutonium oxide, as opposed to radiolytic for-mation of radicals in the gas phase. Onewould expect the latter process to be tempera-ture-independent and surface-insensitive.Presently, we do not know to what extent thealpha radiation may initiate or enhance thesurface reaction. To resolve this issue, furtherwork is needed in which the isotopic composi-tion of the oxide and hence the flux of alphaparticles is changed (239Pu vs. 242Pu).

The results of the long-term experimentssuggest that an equilibrium gas composition isreached, indicating that the rates of recombi-nation and water radiolysis become equal.Based on these preliminary results, extremepressurization of sealed containers as a resultof the radiolysis of water adsorbed on the ox-ide is not likely. Surface-catalyzed hydrogen/oxygen recombination is a primary processresponsible for pressure reduction and/or hy-drogen removal from the system. The kineticdata collected thus far indicate this interplaybetween surface-catalyzed recombination andwater radiolysis. The rate of recombinationserves to limit the potential pressure in thecontainer from water radiolysis.

Figure 2. Simulatingconditions of storedplutonium, researchersobtained pressure-timecurves and massspectrometric results forpure and impureplutonium oxides overthe 50˚C–250˚Ctemperature range in a2% H2/air mixture.

C217-1



O

O

OH

H

H3

H

HH

O

O OO

O

O

O

O

N

N

NN

N NNN

N NN

N

HO

HO HO

HO

OHOH

This article wasprovided byC. E. Ruggiero,M. P. Neu,J. H. Matonic ,and S. D. Reilly(Group CST-18).

Plutonium is thought to exist mostly asvery low-soluble and/or strongly sorbedplutonium(IV) hydroxide and oxide species inthe environment and therefore has low risk ofbecoming mobile or bioavailable. However,compounds that solubilize plutonium orchange the oxidation state can significantlyincrease its bioavailabilty and mobility. Weare examining the fundamental inorganicchemistry of actinides with microbialsiderophores in order to understand howthey could affect actinide biogeochemisty.Siderophores are low-molecular-weight,strong, metal-chelating agents produced bymost microbes to bind and deliver iron intomicrobial cells via active transport systems.

We have focused on the tri-hydroxamatesiderophores desferrioxamine B and E (DFBand DFE, or generically, DFO) because theyare well studied and are readily available(Figure 1). Hydroxamate siderophores havebeen estimated to be present at 0.1-0.01 µMconcentrations in soils. The equilibrium con-stant for the Pu(IV)-DFB complex formationreaction has been estimated to be l030.8. This ishigher than many organic chelators.

We have examined the redox chemistry ofplutonium with DFO and have investigatedthe ability of DFO to solubilize Pu(OH)4 solid.We have found that the Pu(IV)-DFO complexis a thermodynamic sink: no matter what oxi-dation state of Pu is present initially (III, IV,V, or VI), desferrioxamines eventually causethe Pu(IV)-DFO complex to form.

When DFO is added to a Pu(III) solution,the Pu(III) is oxidized quickly to form Pu(IV)-DFO. We have isolated single crystals fromthis reaction. X-ray analysis reveals the prod-uct to beAl(H2O)6[Pu(DFE)(H2O)3]2(CF3SO3)5·14H2O,the first plutonium-siderophore complex to bestructurally characterized. The asymmetricunit contains the Pu(DFE)(H2O)3

+ cation (Fig-ure 2), a hexaaquoaluminum(III), fourtrifluoromethanesulfonates, and seven waters.

The nine-coordinate Pu atom is bound byDFE in approximately one hemisphere and bythree waters in the other. The polytopal geom-etry of the Pu coordination sphere is slightlydistorted, tricapped, trigonal, and prismatic.This is the first discrete molecule containing anine-coordinate Pu(IV) ion. The Fe(III)-DFEcomplex and the DFE ligand (without metal)have also been structurally characterized(Figure 2).

When a solution of DFO is added to a so-lution of Pu(VI) at pH = 2 in an equal molarratio, the Pu(VI) is instantly reduced to Pu(V).The reduction occurs as rapidly as could bedetected even at concentrations as low as 40mM Pu. Stoichiometric titration of Pu(VI) intoa DFO solution showed that up to twelve mo-lar equivalents of Pu(VI) could be rapidly re-duced to Pu(V) per DFO, corresponding tofour reducing equivalents per hydroxamateof the DFO molecule. The Pu(V) solution thatinitially forms slowly reduces to form thePu(IV)-DFO complex.

The rates of both the initial reduction ofPu(VI) to Pu(V) and the subsequent reductionof Pu(V) to Pu(IV) depend on pH. If the reac-tion is performed at pH 1 to 5.5, the reductionof Pu(VI) to Pu(V) is instant, but the subse-quent reduction of the Pu(V) to Pu(IV)-DFO issignificantly slower, taking months to fullyreduce. However, if the pH is raised above 5.5after the initial reduction reaction, the Pu(V) isinstantly and irreversibly reduced to Pu(IV),and the amount of Pu(IV) formed is propor-tional to the pH. If the reaction is startedabove pH=6, the Pu(VI) is instantly and irre-versibly reduced directly to Pu(IV)-DFO.

Interactions of Pu with Desferrioxamine SiderophoresCan Affect Bioavailability and Mobility

Figure 1: Thedesferrioxaminesiderophores DFB (left)and DFE (right).



The rates of the reduction steps also de-pend on the ratio of DFO to Pu. At ratios fromone molar equivalent DFB reacting with onemolar equivalent plutonium (1 DFB : 1 Pu) to1 DFB : 4 Pu, the reduction of Pu(VI) to Pu(V)is instant. At ratios from 1 DFB : 6 Pu to 1DFB : 12 Pu, the rate of reduction is slower,but still very rapid (< 1 hour). For the reactionat a ratio of 1 DFB: 12 Pu, up to 20% Pu(VI) isstill present after 10 minutes, allowing spec-troscopic observation of a probable Pu(VI)-DFB species that must form as a first step inthe reduction process.

The rate of secondary reduction of thePu(V) to Pu(IV) is also faster at higher DFB-to-Pu ratios. The presence of excess DFB acts as athermodynamic driving force for the forma-tion of a stable, soluble Pu(IV)-DFB species. Inthe reaction performed at a ratio of 1 DFB : 12Pu, where the DFB is completely oxidized,only Pu(V) is detected in solution, but a pre-cipitate slowly forms. Presumably, any Pu(IV)that forms as a result of the disproportion-ation of Pu(V) slowly precipitates out of solu-tion as the hydroxide.

Surprisingly, the Pu(IV)-DFO complex isstill reactive. When Pu(VI) is added to a solu-tion of the Pu(IV)-DFB or -DFE complex at pH= 2 or pH = 9, the Pu(VI) is rapidly reduced,despite the fact the DFO is already complexedto Pu(IV). The reaction is slower than the reac-tion without Pu(IV) initially present. Variabletemperature NMR (nuclear magnetic reso-nance) indicates that the Pu(IV)-DFO com-plexes are highly fluxional and may undergoligand exchange with free DFO, which wouldallow for DFO interaction with and reductionof the Pu(VI).

Despite the fact that the Pu(IV)-DFB com-plex has an exceptionally large equilibriumconstant for its formation, the desferrioxaminesiderophores are poor at solubilizing solidPu(OH)4. Pu(IV) hydroxide is slowly solubi-lized by chelates such as EDTA, citrate, andtiron. We have measured rates of approxi-mately 1.13 mM, 0.16 mm, and 0.10 mm perday reaching 310 mM, 41 mM, and 27 mM,respectively, after 253 days. However, the

siderophores DFE and DFB are 50 to 500 timesslower than EDTA with rates of 0.02 (DFE)and 0.002 mM/day (DFB), although they arefaster than controls without a chelator present.These results are unexpected given that thethermodynamic equilibrium constants for theformation of the Pu(IV) tiron, citrate, and

EDTA complexes are lower than for the forma-tion of Pu(IV)-DFO complex. In fact, EDTAsolubilization of Pu(OH)4 was 10 times slowerafter the plutonium is pretreated with DFB(0.11 mm per day). These surprising resultssuggest that the desferrioxamine siderophoresare actually passivating the surface of thePu(OH)4 and thereby inhibiting solubilization.

We have shown that siderophores andpotentially other naturally produced chelatorscould play a major role in the environmentalbehavior of plutonium. (Figure 3.) The basicchemistry is becoming clearer: siderophoreshave high formation constants for Pu(IV),which could keep Pu(IV) species solubilizedand mobile. Their higher formation constantsindicate that siderophores can “steal” pluto-nium from other chelators, such as EDTA andNTA, present with plutonium wastes.Hydroxamate siderophores have a large re-ducing capacity for Pu(VI) and Pu(V), leadingto the formation of Pu(IV) siderophore com-plexes. Siderophores can very slowly solubi-lize Pu solids, but they could also interferewith solubilization of Pu solids by otherchelators.

Figure 2: Metal-freeDFE (left), Fe(III)-DFEComplex (middle), andPu(IV)-DFE Complex(right). Oxygen atomsare shown in red,oxygen atoms of watermolecules are maroon,nitrogen atoms are blue,carbon atoms are black,the Fe(III) atom isyellow, and the Pu(IV)atom is green.



Figure 3. Microbial interactions with actinides in the environment. All processescould increase or decrease solubility and/or mobility depending on specificbacteria and numerous environmental and chemical factors. Key: â =microbially produced chelator (e.g., siderophores, organic acids, sloughedexopolymer. = anthropogenic chelator often present with Pu Contamination.An = actinide species. Æ = reaction involving microbially produced chelators.Æ = reaction does not directly involve microbially produced chelators. 4 =reaction can occur with and without microbially produced chelators.

We are now beginning to address morecomplex questions regarding Pu biogeochem-istry: Can bacteria bioaccumulate plutoniumby actively transporting siderophore-Pu com-plexes? (we think so), by surface absorption ofPu onto the bacteria capsule (we know so), orby unchelated passive diffusion? Will bacteriathat accumulate plutonium increase themobility of plutonium (biocolloidformation) or decrease it (biofilm formation)?

Interactions of Pu with Desferrioxamine SiderophoresCan Affect Bioavailability and Mobility (continued)

Can siderophores or other microbial chelatorssolubilize other forms of Pu in the environ-ment, such as Pu absorbed on mineral, boundby humate, or precipitated by bacteria redoxprocesses? What kinds of ternary complexescan form in the presence of siderophores andother microbial chelators, and will they lead toan increase or decrease in mobility of pluto-nium? How will local environmental changescaused by bacteria effect plutonium specia-tion? These processes could play critical rolesin plutonium biogeochemistry, which has onlybegun to be investigated. Understanding howbacteria effect plutonium environmental chem-istry is crucial for both the safe long-term stor-age of plutonium wastes and for proposedbioremediation strategies of plutonium andthe organic wastes often present withplutonium.

An biocolloid formation:

bacteria or sloughed capsulePassive diffusion

Biomineralization

Biosolubilization

Bioassociation:

surface or capsule binding

Active transport

bioaccumulation

Bioprecipitation

Biosolubilization



Danis, J. A., H. T. Hawkins, B. L. Scott,W. H. Runde, B. E. Scheetz and B. W.Eichhorn, “X-ray Structure Determination ofTwo Related Uranyl Phosphate Crown EtherCompounds” Polyhedron, in press.

Jacobsen, S. D., J. R. Smyth, R. J. Swope, andR. I. Sheldon, “Two Proton Positions in theVery Strong Hydrogen Bond of Serandite,NaMn2[Si3O8(OH)],” American Mineralogist, 85745-752 (2000).

Park, J. J., “Creep Behavior of W-4Re-0.32HfCand Its Comparison with Some CreepModels,” International Journal of RefractoryMetals and Hard Materials 17 331-337(December 1999).

Park, J. J., D. P. Butt, and C. A. Beard, “Reviewof Liquid Metal Corrosion Issues for PotentialContainment Materials for Liquid Lead andLead-Bismuth Eutectic Spallation Targets as aNeutron Source,” Nuclear Engineering andDesign 196 315-325 (April 2000).

Pillay, G., S. R. Billingsley, and J. J. Balkey,“Electrochemical Treatment and Minimizationof Defense-Related Wastes,” Keynote Address,in Environmental Aspects of ElectrochemicalTechnology: Proceedings of the InternationalSymposium, E. J. Rudd and C. W. Walton,eds., 99-39, The Electrochemical Society, Inc.,Pennington, NJ (2000) (also published inFederal Facilities Environmental Journal 11, No.2, Summer 2000, pp. 115-127).

Sheldon, R. I., T. Hartmann, K. E. Sickafus,A. Ibarra, B. L. Scott, D. N. Argyriou,A. C. Larson, and R. B. Von Dreele, “CationDisorder and Vacancy Distribution in Non-stoichiometric Magnesium Aluminate Spinel,”J. Am Ceram. Soc. 82(12), 3293-3298 (1999).

Sickafus, K. E., J. M. Wills, S. Chen, J. H. Terry,T. Hartmann, and R. I. Sheldon, “Developmentof a Fundamental Understanding of ChemicalBonding and Electronic Structure in SpinelCompounds,” Los Alamos NationalLaboratory report LA-UR-99-2731, LosAlamos, NM (1999).

Publications andInvited Talks(January 2000–July 2000)



LosN A T I O N A L L A B O R A T O R Y

Alamos

The Actinide Research Quarterly is published quarterly to highlight recent achievements and ongoingprograms of the Nuclear Materials Technology Division. We welcome your suggestions and contributions.If you have any comments, suggestions, or contributions, you may contact us by phone, by mail, or on e-mail([email protected]). ARQ is now on the Web also. See this issue as well as back issues on-line (http://www.lanl.gov/Internal/divisions/NMT/nmtdo/AQarchive/AQhome/AQhome.html).

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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 endorsementof 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 NationalLaboratory 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 itstechnical correctness.

NewsMakers ■ Gary H. Rinehart (NMT-9) is the winner of the American Nuclear Society’s Mishima Awardthis year. The Mishima Award was established in 1991 to honor Dr. Mishima Yoshitsugu,Professor Emeritus of the University of Tokyo, to recognize an individual for his/heroutstanding contributions in research and development work on nuclear fuels and materials.Reinhart is recognized for his sustained contributions to the development, production, testingand decommissioning of 238Pu heat sources for medical, space and terrestrial applications.

■ D. Kirk Veirs (NMT-11) is one out of eight individuals honored as part of the 2000 CareerDevelopment Mentor Awards. The award recognizes and applauds exemplary mentoring at theLaboratory.

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2nd/3rd quarter 2000 The Actinide Research Los Alamos ... · and economic growth, the same effi-ciency of energy sources, and the same percentage of carbon-based fuels. Under business-as-usual,