Post on 15-Feb-2019
Spent Fuel and Waste Science and Technology
Pu Incorporation into Reduced Iron Oxide Phases
Enrica Balboni and Mavrik ZavarinLawrence Livermore National Laboratory
SFWST Annual Working Group MeetingLas Vegas, Nevada
May 22-24, 2018
LLNL-PRES-751812This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344. Lawrence Livermore National Security, LLC
With support from Melody Maloubier and Brian Powell (Clemson University)Corwin Booth (Lawrence Berkeley National Laboratory)
Spent Fuel and Waste Science and Technology
TitleMay 23, 2018
Overview of Activity
2
Water
Mineral
Pu Pu
Pu
PuPu
Water
Mineral
Intrinsic colloidsWater
Mineral
Pu
PuPu
PuPu
PuPu
Pu
Pseudo-Colloidal transport
Water
Mineral
Pu
Pu
PuPu
Pu Pu
Pu
Microbial activityWater
Mineral growth
Pu
PuPu
PuPu
Pu
PuPlutonium uptake
This work: coprecipitation of Pu with iron oxides
Radionuclide transport controlled by release, sorption, and colloid facilitated transport processes
How do repository corrosion processes affect the mobility of RNs?
Spent Fuel and Waste Science and Technology
TitleMay 23, 2018
Effect on Repository Performance or Safety Case Confidence
3
Fuel Matrix Degradation Model and Canister Corrosion (ANL) are a key component for evaluation of repository performance assessment and safety case models
Radionuclide may be entrained in the corrosion products
Radionuclide association with corrosion products may lead to reversible (sorption) or irreversible (coprecipitation) sequestration of radionuclides
Lower radionuclide release rates
From Jerden, Frey, and Ebert, 2017
Spent Fuel and Waste Science and Technology
TitleMay 23, 2018
Integration with GDSA/PA and/or the Safety Case
4
Steel corrosion model has been added to the fuel matrix degradation model (FMDM) developed at ANL
Model provides a kinetic source for H2 and Fe2+
The FMDM is intended to be integrated with the GDSA PA model
From Jerden, Frey, and Ebert, 2017
Spent Fuel and Waste Science and Technology
TitleMay 23, 2018
Example Results – Pu Interaction with HFO and Goethite
Ferrihydrite precursor
• pH • time • T°C
HematiteFe2O3
GoethiteFeOOH
Synthesis RoutesRoute A “Coprecipitation” Route B “Sorption”
Method A
Method B
Goethite Hematite
Total of 12 samples
Final Product:Hematite OR
Goethite
CONCLUSION: Pu incorporates into goethite but not into hematite
Spent Fuel and Waste Science and Technology
TitleMay 23, 2018
Example Results – Pu Interaction with HFO and Goethite
Method A
Method B
Goethite Hematite
Total of 12
samples
Focus of the talk: goethite
synthesized with 3000 ppm Pu and
its ferrihydrite precursor
Does the initial association of Pu with the ferrihydrite precursor (sorbed vs coprecipitated) affect the association of Pu with the final
crystalline product
Question
Spent Fuel and Waste Science and Technology
TitleMay 23, 2018
Ferrihydrite EXAFS: PuO2 in “sorbed” ferrihydrite
Spent Fuel and Waste Science and Technology
TitleMay 23, 2018
Goethite EXAFS: PuO2 in “sorbed” ferrihydrite preserved
TEM confirmed PuO2 TEM
Spent Fuel and Waste Science and Technology
TitleMay 23, 2018
Pu Acid Leaching: Nature of Incorporation Affects Pu Release
0
0.5
1
1.5
2
2.5
3
3.5
100
600
1100
1600
2100
2600
3100
3600
0 2 4 6
Fe (p
pm)
Pu (n
g)
HNO3 (M)
Pu-GA Pu-GB Fe-GA Fe-GB
More Pu leached from Goethite (B) than Goethite (A)Goethite (A): formed from aging of ferrihydrite coprecipitated with Pu; Goethite (B): formed from aging of ferrihydrite with sorbed Pu.
Spent Fuel and Waste Science and Technology
TitleMay 23, 2018
Relationship to 2012 UFD Roadmap and R&D Priority Ratings
10
Task #
Task Name/
(and Work Package
number -- if needed or helpful for
more specificity)
Brief Task Description
includingRelevance (and/or input) to PA/GDSA
(nPA = not direct input to PA)
Personnel/Lab
Code(if
applicable)
Importance to Safety Case
(ISC)
(H, M, or L -- see ISC table
definitions)
(Identify applicable
Safety Case element from the provided
figure)
Current "State of the Art" Level
(SAL = 1, 2, 3, 4, or 5 -- see SAL table definitions)
(Give brief update to applicable state-of-the-art "discussion(s)" shown in UFD Roadmap App. A, i.e., those discussion(s) for the
highest scoring related FEPs)
Short-term (1 yr) R&D Priority Scores
& Brief FY19 Work Scope Proposal
(Priority Score = H, M, or L, based on combined ISC and SAL -- see PS
table definitions)
(Also give Roadmap Score for related FEP)
Related UFD Roadmap
Issue(s)/FEP(s), and associated UFD Roadmap priority scores*
(Find highest scoring related
FEP in App. B of UFD Roadmap)
Other Notes/Comments
(e.g., type of linkage to PA-GDSA; inputs
required and/or linkages to other
models and experiments)
4 SNF Degradation
• Mixed potentialmodel of spent fuel matrix degradation (including possible effect of Fe corrosion)• Radiolysis
Frederick,Hammond
SNLJerden,
ANL Caporuscio
LANL Balboni LLNL
PFLOTRAN/FMDM
ISC = High
SC element 3.3.1b
SAL = 5
From Roadmap: U.S. program evaluated the long-term behavior of LWR UOX in oxidizing environments. Other programs have evaluated and are modeling the degradation of UOX and MOX in reducing environments. Little information is available regarding the degradation/alteration of otherUNF types.
PS Matrix Score = H; Roadmap Score = H
For FY19 continue work on FMDM model development and code optimization
• Primary FEP is 2.1.02.01; score = 4.01• Other related FEPs have lower scores
• Direct implementation in PFLOTRAN already complete and now at the testing stage.• Additional development and more efficient coding suggested
9
Waste Package
Degradation Model
(mechanistic)
• Degradation of waste packages and canisters• Carbon steel; stainless steel; copper waste packages Experimental Data• Include various degradation processes (SCC, GC, LC, MIC, early failure)
Jove ColonSNL
Caporuscio LANL
Balboni LLNL
PFLOTRAN et al.
• FEPs 2.1.03.02, 2.1.03.03, 2.1.03.04, 2.1.03.05; scores = 4.34
• Direct implementation in PFLOTRAN suggested (1D model), similar to SNF degradation• Currently evaluating development of thermodynamic relations for high T 316 SS corrosion phase assemblage (e.g., chromite, magnetite)
Spent Fuel and Waste Science and Technology
TitleMay 23, 2018
Current State of the Art and Past Accomplishments
11
Current State of the Art:– ANL FMDM includes fuel degradation and steel corrosion processes
– Role of corrosion products on radionuclide immobilization not included in FMDM or PA models
Past Accomplishments:– Goethite favors uptake of Pu over hematite: crystallographic considerations
– EXAFS and Pu leaching results indicate that a different association of Pu to the ferrihydrite precursor (Pu sorbed or coprecipitated) results in a different association of Pu in goethite
HEMATITE: “compact” structure
GOETHITE“open” structure
Spent Fuel and Waste Science and Technology
TitleMay 23, 2018
Future R&D & Integration Timeframe
12
FY19 effort will focus on radionuclide (Pu) incorporation into reduced iron oxide phases (magnetite, green rust, etc.)
Longterm need to incorporate radionuclide interaction with corrosion products into FMDM or downstream models
From Jerden, Frey, and Ebert, 2017