nuclear science education and research opportunities at...

Nuclear Science Education and Research Opportunities at LLNL

Mavrik Zavarin

Director, Glenn T. Seaborg Institute

Lawrence Livermore National Laboratory

UC Davis

July 12, 2016

FIG. 3: Left: Pu(OH)4(H2O)19 cluster optimized at the UHF level of theory. Right: Snapshot from

an ab initio MD simulations of Pu(OH)4 in a periodic box of water. In both models, four hydroxyl

and three water molecules are found in the inner shell, with two of the hydroxyls occupying the

axial positions while the other two hydroxyls and three waters are arranged around the equatorial

positions.

Given that UHF predicts equilibrium structures that are in qualitative agreement with

MP2 for small Pu(OH)4(H2O)n (n = 1 � 3) clusters, we employ UHF to carry out the

geometry optimization of larger clusters of n = 7 � 19 water molecules, with the largest

cluster (n = 19 waters) shown in the left panel of Figure 3. This cluster has enough water

molecules to complete a second solvation shell and begin filling in a third shell. At this

size, the essential features of the inner coordination shell appear converged: there are four

hydroxyl and three water molecules in the inner shell, with two of the hydroxyls occupying

the axial positions while the other two hydroxyls and three waters are arranged around the

equatorial positions, reminiscent of the hydration structure of linear actinyl ions.

It should be pointed out that drawing conclusions about metal ion coordination numbers

in liquid water solely on the basis of the optimized structures of large gas-phase clusters

should be done with caution. The optimization methods employed in this work only find

local minima and are not guaranteed to deliver a global minimum; robust algorithms for

finding the global minimum energy structure on complex potential energy landscapes remain

an open research problem. Our situation is further complicated by the fact that the first

coordination shell around Pu(IV) consists of two distinct species, OH� and H2O, which leads

12

https://seaborg.llnl.gov

Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx 2

Disclaimer •! I only found out about the UC Davis NAT Summer School last week •! My slides were thrown together rather quickly •! My one goal is to make you aware of education and research

opportunities at LLNL

Because NSSC consortium includes:


Outline

•! A bit about myself •! Nuclear Science research and education opportunities LLNL

•! Physical and Life Sciences Directorate •! Nuclear and Chemical Sciences division •! Seaborg Institute •! Postdoc program •! Other opportunities

•! Examples of my research at LLNL


Director of the Glenn T. Seaborg Institute which focuses on: Nuclear forensics Super heavy element discovery Environmental radiochemistry

A bit about myself

•! UC Berkeley undergrad in Chemistry (1993) •! UC Berkeley PhD in Soil Chemistry (1993-1998)

•! “Se, Ni, and Mn interaction with calcite” •! Hired at LLNL to develop model of radionuclide sorption to mineral

surfaces for reactive transport models (1998) •! Began managing ! contaminant transport project at the Nevada Test

Site (2005) •! Developed collaborations and teaching outside LLNL (2007)

•! Clemson University, HZDR Dresden, Las Positas Community College, etc.

•! Slowly developed a research program in actinide environmental research (2008-)


Research Team and Funding

NA-22


My research group’s goal is to reliably predict the mobility and cycling of radionuclides (actinides) in our environment

Th(IV) FPMD

Pu-cell interaction

Pu-goethite TEM

Hanford NanoSIMS

Conceptual models

Transport simulations Pu Batch sorption

Np sediment profiles Ravenglass estuary

Numerical models


"! One of the Department of Energy’s NNSA National Laboratories

"! Located in Northern California’s “bay area”

"! 2.5 km2 campus

"! ~6000 employees

"! Mission: Strengthening the United States' security by developing and applying world-class science, technology and engineering

Lawrence Livermore National Laboratory


LLNL Organization


Nuclear and Chemical Sciences Division Division Leader: Sonia Létant; [email protected] Find us at: https://pls.llnl.gov/people/divisions/nuclear-and-chemical-sciences-division !"#$%&''&()*$$!"#"$%&"'("")'"*)"$+,"'-.'/0.(%1".2%3')45,-6,'%.('64"1-,2$5'27')$7#-("'-..7#%+#"',730+7.,'27',0))7$2',2768)-3"',2"9%$(,4-)'%.('724"$'.%+7.%3',"60$-25')$7&$%1,'-.630(-.&'/7$".,-6,:'.063"%$',%/"25'%.(',"60$-25:'%.('.7.;)$73-/"$%+7.''!"#$+,-.'$(/$#,',0#12*$

#! <%(-764"1-,2$5'#! =063"%$'%.('>%$+63"'>45,-6,'#! <%$"'?#".2'@"2"6+7.'#! <%(-%+7.'@"2"6+7.'#! =063"%$'@%2%'%.('A4"7$5'#! B.%35+6%3'C4"1-,2$5'#! D7$".,-6'E6-".6",'

'


Nuclear and Chemical Sciences Division Develop fundamental physics and chemistry knowledge to support national security programs including stockpile stewardship, forensics, nuclear safety and security

"! 324'&1'$05$52,$/#()6,#*$!"#$#%&'()"')%!*"+,-%!#%&'(.'/-0*"'-%!',1*')%#$*"+*''

"! 7"1-,0#$#,016()'*$2*-$#%&',1*("3'-%!'*45*"#/*%,',('5"*!#6,'5"(5*"7*+'(.'%)68*#'.-"'."(/'+,-9#8#,3'

"! 80.&(12,%&'5#4*$)%!*"+,-%!#%&'."-67(%-7(%:'+,)!3#%&'58-+/-'*;*6,+'(%'%)68*-"'"*-67(%+:'*458("#%&',1*'61*/#+,"3'(.',1*'1*-$#*+,'*8*/*%,+'

"! 7"1-,0#$.,5,16()$0).$0-9(#&52%'*$8*-!#%&',*61%(8(&3'!*$*8(5/*%,'."(/'%)68*-"'#%6#!*%,'"*+5(%+*',('"-"*'*$*%,'!*,*67(%''

"! 7"1-,0#:$12,%&10-:$0).$;&(-(9&10-$/(#,)'&1'*$!*$*8(5#%&'6)<%&=*!&*'-%-8376-8'/*,1(!+'-%!',((8+',(')%6($*"'%*2'+#&%-,)"*+'

Our Investment Areas

LLNL-PRES-xxxxxxxxxxxx11 11


Mission To strengthen interactions between LLNL and the academic community in nuclear chemistry/actinide science

To develop a robust pipeline in nuclear chemistry/actinide science applied to:

! Nuclear forensics & attribution ! Radiochemistry for NIF diagnostics

! Environmental Radiochemistry

Outreach

Environmental Radiochemistry

The Seaborg Institute Facilitates LLNL - academic collaborations in nuclear chemistry/actinide science

Science Education

The Seaborg Institute facilitates collaborations and provides administrative support to collaborators and students in nuclear chemistry/actinide science

! Nuclear Forensics Summer program ! SULI internships in nuclear science

! ACP internships in nuclear science (including NSSC students)

! VSP visiting scientists in nuclear science

12 12

"The education of young "The education of young people in science is at least people in science is at least

as important, maybe more as important, maybe more so, than the research itself.” so, than the research itself

-Glenn T. Seaborg -Glenn T. Seaborg


GTSI Nuclear Forensics Summer Program

8 week program for graduate students (and some undergrads) interested in Nuclear Forensics (and, more broadly, nuclear chemistry) •! Students paired with mentors to perform research project (~25 students) •! Weekly seminar series on Nuclear Forensics/Radiochemistry topics •! Student poster session •! Aligned with many other summer student programs

•! Hundreds of undergrad/grad students come to LLNL over summer EXAMPLES: •! Applying Auxiliary Field Quantum Monte Carlo methods to actinide

complexes •! Characterizing nuclear fallout debris using TEM, NanoSIMS, and

radiography •! Automation of radionuclide deposition in NIF capsules •! Development of novel radionuclide fast separations •! Delayed Neutron Activation Analysis (DNAA) for Nuclear forensics •! Radiochemistry and noble gas application to the hydrologic cycle


"! LLNL’s postdoc program is larger than ever •! >200 postdocs lab-wide •! 130 postdocs in PLS

"! Active lab-wide Postdoc Association run by postdocs that provides both professional development and social opportunities

"! Lawrence Fellowship provides fellows opportunities to conduct their own research agenda

The LLNL Postdoc Program Provides opportunities for scientists to pursue world-class research

PLS Postdoc Program: https://pls.llnl.gov/careers/postdoctoral-program LLNL Postdoc Program: https://postdocs.llnl.gov

Lawrence Fellowship: https://fellowship.llnl.gov

PLS Postdoc Program Contacts: Sarah Chinn:, Director [email protected] Camille Vandermeer, Adminstrator [email protected]


"! Annual post-doc poster symposium (with awards)

"! Post-docs typically have ~25% of their time to pursue career development opportunities

"! 35% of the lab’s postdocs are Foreign nationals

"! LLNL’s post-doc program is in a very active hiring mode right now

Additional LLNL post-doc info


LLNL postdocs "! Carry out & publish original research "! Develop into PI scientists "! Move on to jobs at national labs, academia, industry


"! Science Undergraduate Laboratory Internship (SULI) (DOE program) •! 10-16 week program with some compensation, fall/spring/summer

"! Academic Cooperation Program (ACP)/Visiting Scientist Program (VSP) •! Graduate/undergrad students, post-docs, scientists, unpaid, access to LLNL

facilities

"! Post college appointments •! Paid LLNL employee, must be recent graduate (undergrad of masters)

"! Livermore graduate scholar program •! Paid LLNL employee, graduate students, perform research at LLNL, 4/15

"! Lawrence Fellows •! Paid LLNL employee, postdoc, personal research at LLNL, 10/1

"! And others!

Other internship, fellowship, job opportunities at LLNL


A bit about GTSI Research

Nuclear forensics & attribution Radiochemistry for NIF diagnostics and heavy element discovery

Environmental Radiochemistry


Visiting students and faculty can use of state-of-the-art facilities

NanoSIMS: high resolution ultra-high sensitivity isotopic and chemical characterization at the nanoscale (50nm)

Titan SuperSTEM: chemical and structural characterization at the nanometer scale. Atomic Scale imaging with a spatial resolution of < 8nm.

Multi-collector, plasma-source mass spectrometer: isotopic measurement and concentration information ~10-4pCi, cheaper than AMS,

Accelerator Mass Spectrometer: ion counting, backgrounds of 105 atoms for Pu ~10-5 pCi, ~10-18M

Nuclear Magnetic Resonance Facility: Molecular scale information on both solutions and solids

Supercomputing: advanced, atomic scale simulations 81920 processors on BlueGene/L, AMD clusters up to 13,824 processors


1. Seaborg Institute staff are leaders in nuclear and biological forensics

Scientific Challenge "! Goal: reconstruct a nuclear

incident quickly with high fidelity "! Current focus is on developing

signatures --the chemical, isotopic and morphological fingerprints of interdicted illicit materials

20

NanoSIMS"


"! Goal: Expanding our knowledge of the Periodic Table "! Focused on discovery of super heavy element

•! 113 – 118 was performed in collaboration with the Flerov Laboratory for Nuclear Reactions in Dubna, Russia

"! Rare isotopes are provided by LLNL for use as target materials – irradiations are performed in Dubna

"! Reaserch expanded to use of NIF for radiochemistry research

2. Heavy element research at LLNL includes the physics and chemistry of the heaviest elements

Heavy elements are produced by bombarding actinide targets with calcium-48 beams

Recently proposed names for elements 114 (Flerovium) and 116 (Livermorium)


3. Environmental radiochemistry

50 nm 50 nm

100 nm

Pu-oxide on quartz

1 µm!

ER20-5 #1

Cheshire

1 µm!

Goal: Determine the processes that control the fate and transport of actinides in the subsurface


Our goal is to reliably predict the mobility and cycling of radionuclides in our environment

Th(IV) FPMD

Pu-cell interaction

Pu-goethite TEM

Hanford NanoSIMS

Conceptual models

Transport simulations Pu Batch sorption

Np sediment profiles Ravenglass estuary

Numerical models


"! First principles molecular dynamics calculations on Th(IV) ion in water indicate that: •! Coordination number around Th(IV) decreases as the number of coordinating

hydroxyl ions increase •! This clarifies the discrepancy between synchrotron-based XAS observations and

ab initio model predictions

Ab Initio modeling of water and hydroxide coordination around actinide ions

Supercomputing


"! The pressure dependence of the rates of ligand exchange for the same [NpO2(CO3)3]4- and [UO2(CO3)3]4- complex were compared.

"! The experiments show a distinct difference in the pressure dependencies of rates of exchange for the uranyl and neptunyl complexes.

"! This suggests that the mechanisms of ligand exchange may change across the actinide series, possibly due to the influence of f-electrons (in collaboration with W. Casey, U.C. Davis)

Nuclear Magnetic Resonance of actinide-ligand complexes

<""('"2'%3F'>6,-'?"3+,@''<=>>:$CGH:'1IJK;1IJI'

Nuclear Magnetic Resonance


TEM of actinide precipitates

A

goethite

goethite

D

E

3.08 Å 3.08 3.08

Pu colloids

goethite

E E 50 nm

Pu colloids

F

B

C d[{114}p=2.59 Å

d[{132}p=2.96 Å

d[{222}p=3.18 Å

C

"! TEM used to determine crystal structure at 2-5 nm and ~50 ppm

"! Pu nano-colloids formed in situ on goethite has a epitaxial lattice distortion structure, matching bcc Pu4O7

"! Structure identical regardless of the initial oxidation state of Pu (IV or V)

"! Similar behavior observed at 80C and on the scale of months

5 nm

Pu4O7 on goethite

5 nm

PuO2

Transmission Electron Microscopy


NanoSIMS Characterization of actinide-contaminated sediments

•! Within the 200 Area at the Hanford Site, the Plutonium Finishing Plant disposed of organic and aqueous wastes at several unlined “cribs”.

•! What are the characteristics of Pu in the subsurface compared to the shallow sediments? •! (Collaboration with A. Felmy, PNNL/WSU)

NanoSIMS ion images of Si, and Pu detected in Hanford sediments recovered 25m below ground surface beneath the Z-9 trench. Pu is strongly correlated with minerals shown on the left panel. Photo from R. Kips

NanoSIMS


Environmental behavior of Pu at Hanford

Pu Cs

Most likely, the Pu at Hanford that was deposited with DNAPL (TBP), pH ~2.5 migrated unhindered through the vadose zone dissolving calcite to neutralize the pH.


Cameca NanoSIMS 50 - Secondary Ion Mass Spectrometer

L"."$%+7.'7/',"67.(%$5'-7.,'24$70&4',)0M"$-.&'9-24'N;'7$'C,O')$-1%$5'-7.,F''

We have developed the capability of imaging Pu on NanoSIMS as low as 1 ppm and 200 nm


Pu & Np sorption to goethite CAMS ultratrace analysis

•! Pu sorption is linear on goethite over 8 orders of magnitude (<1E-9 M) •! Sorption is independent of initial oxidation state •! Np sorption over the same concentration range does not exhibit linearity

Snow et al. (2012) Coll. Interf. Sci.

CAMS

Pu(IV) Pu(V)

Pu sorption to goethite

Snow et al. (2012) Coll. Interf. Sci.

Np(V)sorpion to goethite

Accelerator Mass Spectrometry

Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx 32 32

237Np (and other RNs) distribution near Sellafield, UK

Collaboration with Francesca Quinto (KIT), Gareth Law (Manchester)

RN separations – MC-ICP-MS


Noble gas and 14C migration from underground nuclear tests

An underground nuclear explosion (UNE) will yield a variety of volatile and semi-volatile byproducts (Bowen et al., 2001) that provide signatures of the presence, nature, and age of the underground nuclear test.

Conceptual model of radionuclide migration from the Milk Shake test to Well ER-5-5. The leading edge of a 3H plume has reached Well ER-5-5. High 3He is indicative of a combination of saturated groundwater flow and gas-phase transport of the decay product of 3H. Note: Cavity radius is calculated using the maximum of the announced yield range in DOE/NV (2000) and Equation (1) in Pawloski (1999). From Navarro-Intera (2014).

AMS + Noble Gas Mass Spectrometry


The Plutonium

SFA

Thank you! For questions about LLNL opportunities: [email protected]

DOE-NE Used Fuel

Disposition


BACKUP


Radioactive contamination is not just a nuclear waste repository issue

YuccaFlat

FrenchmanFlat

PahuteMesa

UndergroundNuclear Event=

0 5 10 Miles

0 15 km

Simulate RN transport $ evaluate risk to environment

The Nevada Test Site (NNSS)

Nevada Test Site (Nevada National Security Site) Fukushima Hanford Sellafield Savanah River Site Etc. US budget for EM is ~1B per year

Test configuration


Environmental behavior of RNs at the Nevada Test Site: Note: It’s a big place

LLNL-PRES-xxxxxxxxxxxx37 37


Environmental Management goal is to effectively predict RN transport and risk over the next 1000 years Unconstrained modeling leads to significant overprediction of RN transport


Typical RN contaminants

"! 3H, 14C, 36Cl, 99Tc, 129I, 90Sr, 137Cs, Pu, Np, U are dominant radionuclides at the NTS


Chancellor


Noble gases and 14C may yield information regarding the nature of underground nuclear tests An underground nuclear explosion (UNE) will yield a variety of volatile and semi-volatile byproducts (Bowen et al., 2001) that provide signatures of the presence, nature, and age of the underground nuclear test. Migration of volatile (noble gases) and semi-volatile (14C) indicators through the vadose (zone above the groundwater table) zone may yield near-surface signatures of a subsurface nuclear test that are persistent and detectable at considerable distances away from ground zero.

Conceptual model of radionuclide migration from the Milk Shake test to Well ER-5-5. The leading edge of a 3H plume has reached Well ER-5-5. High 3He is indicative of a combination of saturated groundwater flow and gas-phase transport of the decay product of 3H. Note: Cavity radius is calculated using the maximum of the announced yield range in DOE/NV (2000) and Equation (1) in Pawloski (1999). From Navarro-Intera (2014).


NEW PROJECT: Scientific Focus Area: Characterization of field samples from Pu contaminated sites

In collaboration with SRS and Clemson Savannah River Site: Characterization of sediments associated with the Pu/Np-doped lysimeter coupons

Radiological Field Lysimeter Experiment (RadFLEx) at the Savannah River Site


Samples and Depths (ft) B1HK27 (57-58) B1HK32 (70-72) B1HK42 (118-121) B1HVC8 (49-50) B1HK15 (~63-65) (~19.5m) B1HY61 (~81-82) (~25m) Uncontaminated sediments are sandy soils with quartz, clays, calcite, feldspar, minor oxides Collaboration with A. Felmy, PNNL

Cantrell et al., 2008


Si Al

Fe Pu

Plagioclase Feldspars

Pu is associated with feldspars B1HY61 grains


BSE

Si Al

Fe Pu

B1HK15: Pu is associated with Fe along the rim of the minerals

Next steps: Characterize Pu distribution in shallow Hanford sediments with high Pu Select samples to be used in desorption experiments XAS effort led by Los Alamos team

nuclear science education and research opportunities at...

Documents