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Cementitious Barriers Partnership DOE Project Overview

C. Langton (PM/PI)

D. Esh, M. Furman, J. Phillip, US NRC

S. Mahadevan, A. Garrabrants, K. Brown, CRESP, Vanderbilt U.

H. Van der Sloot, R. Comans, J.C.L. Meeussen, ECN (NL)

E. Garboczi, K. Snyder, NIST

E. Samson, J. Marchand, SIMCO, Inc.

C. Langton, R. Dimenna, G. Taylor, SRNL

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Partnership Members

• Department of Energy – Office of Environmental Management Principal supporting agency Primary end-user

• Nuclear Regulatory Commission Oversight & Research

Divisions Primary end-user

• National Institute of Standards and Technology

• Savannah River National Laboratory

• Consortium for Risk Evaluation with Stakeholder Participation (CRESP)

• Energy Research Centre of the Netherlands

• SIMCO

Expert Advisory Panel organized through CRESP Independent Peer Review Board

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Project Description • Technology Needs / Requirements

Develop a reasonable and credible set of tools to predict the structural, hydraulic and chemical performance of cement barriers used in nuclear applications over extended time frames (e.g., >100 years for operating facilities and > 1000 years for waste management).

• Mechanistic / Phenomenological Basis

• Parameter Estimation and Measurement

• Boundary Conditions (physical, chemical interfaces)

• Uncertainty Characterization

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Project Description• Risk / Cost Issues

Current PA approach may not adequately represent risk and uncertainty of disposal and containment systems and practices

• Waste form selection, contaminant loading, optimization• Disposal decisions• Remediation and D&D options evaluations

Design improvements of future facilities may not be realized due to lack of mechanistic understanding of cementitious barrier performance

Need for transparency, consistency, and peer review for evaluation of long-term performance may give rise to increased:

• Cost• Schedules• Stakeholder concerns

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Project Description

• Technical Approach:

Phase 1• State of the Art reviews (LLW / ILW CBs andPAs)

Phase 2• Computational tool enhancements including uncertainty

analyses (STADIUM, LEACH XS, THAMES) • Parameter value determinations / measurements • Suite of parameter test methods• Improved mechanistic models• Test bed workshop and recommendations for US program

Phase 3

• Integration of component models• Model validation• Uncertainty evaluation (parameter, model, numerical)

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DOE ApplicationsLAW Disposal

Perimeter riser

Center riserConcrete dome

Steel tank

Concrete wall

Concrete base mat

Intruder Barrier

Backfilledsoil

Backfilledsoil

Undisturbed soil

Solidified Mass (10 CFR 61.56 Stabilization)

Bulk Fill

Tank 17 Closure

Top Dressing

Saltstone Vaults

Components in Grout

Tank Closure

D & D Entombment

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Nuclear Facility Applications

Reinforced Concrete

Pool Building

NaturalSoil

Spent Fuel Pool

Fuel Pool

Structural fill

Ground Surface

Water Table

Water TableContainment

Structure

Structural Fill

Atmosphere

Nuclear Power Plant

Ground Surface

Reactor Internals

Entombed Structure

Structural fill

Cover

Ground SurfaceWater Table

Entombed Structure Waste

Materials

Entombment

Water Table

Cover

Reinforced Concrete

Wasteform

Ground Surface

Structural fill

LLW Disposal

Atmosphere

NaturalSoil

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CBP Interest Area

Integration of CBP Tools with PAs

Atmosphere

Soil layers

Cap layers

Source

Vadose Zone(s)

Saturated Zone(s)

Surface Water

EngineeredSystem

Exposure Scenarios

Failures

Risk

Airborne (diffusion)

Waterborne (advection)

Airborne (barometric pumping)

Airborne (resuspension/deposition)

Plant-induced

Animal-induced

CBP focus:

• Cementitious materials performance as part of engineered system and their interfaces with natural system.

• To provide near-field source term.

• Uncertainty approach being developed to be broadly applicable to PA process.

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Important ParametersHydraulic Properties

Hydraulic Conductivity (dual porosity: matrix and cracks) Total and Transmissive Porosity, Density Water Diffusivity (e.g., Richard’s Eqn) Dissolved ion Diffusivity Tortuosity

Chemical Properties Retardation Factors (Kds), Chemical Reduction Capacity, Buffering Capacity

Mineralogy (matrix, radionuclides, other phases) Constituent Speciation Chemical Degradation (e.g., carbonation, oxidation, sulfate attack, rebar

corrosion)

Structural Properties: Physical loads or seismic events

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Technical Strategy/Approach —Integrated Long-Term Degradation

Chemical degradation and physical structure evolution are coupled.Physical stress External loading Drying shrinkage Seismic events Settlement

Chemical Alteration Oxidation, Neutralization Leaching Pore & crack evolution

• Dissolution and cracking• Precipitation & sealing

Expansive reactions & corrosion• Carbonation• Sulfate attack• Rebar corrosion

Microcracks• Increase porosity

• Increase interaction pore water/surface

Through-cracks• Preferential flow

path• Diffusive and

convective release• Loss of strength

Spalling• Loss of

cohesiveness• Two body problem

• Eventual release from “granular”

material

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LAW Waste Disposal Vault – Conceptual Closure Model

C GSoil

A

B

C

C

D

Soil

(not to scale)

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Type IIIA Tank – Conceptual Closure Model

Reducing Grout

Intrusion Barrier

Grout

Tank Wall

Soil

Grout

Tank

WallSoil

Tank Wall

Intrusion

Barrier

Grout

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Spent Fuel Pool – Conceptual Model

Water

Concrete

Soil

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CBP Reference Materials

Reference Solids• Waste Form• Reinforced Concrete (historic facilities)• Fill/Entombment Grout• Advanced Design Concrete (future facilities)• Soil

Reference Solutions• Deionized Water• Porewater (e.g., LAW wasteform, concrete)• Groundwater (e.g., Hanford synthetic groundwater)• Process Water

Reference Gases• Vadose Zone Atmosphere – air adjusted for CO2, O2, moisture

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Technical Status and Results

• Form CBP (Phase 1) MOU complete CRADA and IAA complete July 1 IAA in progress Advisory Committee (being set up by CRESP

• State of Art Documentation (Phase 1) March 2009

• Model Development (Phase 2a) Needs: December 2008 Demonstration of STADIUM, LEACH XS, THAMES on 1-D

reference case: May 2009 Enhance Component Modules: December 2009

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Expected Project Impact

• Reduced uncertainty and improved consistency for PAs

• Improved system designs (waste management and new facilities)

• Monitoring and maintenance approaches for extended (100s, 1000s yr) service life

• Updated guidance documents (assessment tools, test methods, data)

• Industry-wide technical basis for evaluation amongst stakeholders (DOE, NRC, state regulators, others)

• Assessment transparency

• Improved technology foundation and integration of existing / new science

• Template for assessment of complex systems

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Supporting Overheads

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Project Description – Technical Strategy / Approach

• Reference Cases – provide basis for comparison and demonstration of tools under development Cement Waste Form in Concrete Disposal Vault Grouted HLW Tank Spent Fuel Pool Materials – surrogate LAW cementitious waste form, reducing grout,

reinforced concrete (historical), reinforced concrete (future)

• Integration with GoldSim PA framework• Coordinated experimental and computational program

Conceptual model improvement Define test methods and Parameter measurements Model validation

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Project Management Summary

• Work ongoing for less than one month• Budget summaries are unavailable• WBS is being developed for project

management tracking• Project management meeting scheduled for

5-8 August 2008• FY’09 scope will be developed in PTS-03

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DOE Applications

Saltstone

Clean Cap

SaltstoneSaltstone Saltstone

Infiltration

AnnualPrecipitation

Infiltration Barrier

Evaporation &Transpiration

Run-off to surface stream or river

Ground Water

LeachedContaminants

Contaminant levels withinacceptable limits

Water Table

Top Soil

Run-off MonitoringWell

Saltstone Vaults

Atmosphere

Soil layers

Cap layers

Source

Vadose Zone(s)

Saturated Zone(s)

Surface Water

EngineeredSystem

Exposure Scenarios

Failures

Risk

Screening Risk Evaluation

Cap: Poisson(Cap Type)Drum: Weibull(Stacking, Liner, etc.)

Near-field: GS Cell Pathway ElementFar-field: Gaussian Plume Model

All layers: GS Cell Pathway Elements

All layers: GS Cell Pathway Elements

Loose: GoldSim (GS) Source ElementBoxes: GoldSim (GS) Source ElementDrums: GoldSim (GS) Source Element

All layers: Network Pathway Elements

All layers: GS Pipe Pathway Elements

All layers: N Cell Pathway Elements N

Public: GS Receptor ElementsWorker: GS Receptor Elements

Airborne (diffusion)

Waterborne (advection)

Airborne (barometric pumping)

Airborne (resuspension/deposition)

Plant-induced

Animal-induced

Exposure: Morbidity, mortality, cancer, HQAccident: Injuries, fatalities, probabilities

Possible Detailed Risk Evaluation

Cap: Poisson(Cap Type)Drum: Weibull(Stacking, Liner, etc.)Other types/distributions possible

Near/Far: AERMOD plume model (EPA)Various other models available

Cap/soil: HELP landfill model (EPA)Other landfill/engineered barrier models available

All: DUST-MS release model (INL)Other source release models available

All layers: TETRAD transport model (INL)Various other transport models available

Public: GS Receptor ElementsWorker: GS Receptor Elements

Exposure: Same + cumulative, YPLLAccident: Injuries, fatalities, probabilities

All layers: TETRAD transport model (INL)Various other transport models available

All layers: GSFLOW coupled model (EPA)Other surface water models available

CBP Interest Area

Technical Strategy/Approach—Integration of CBP Tools with PAs

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Technical Status and Results• Task 1

Review of DOE and NRC PA Approaches PA R&D needs

• Task 2 (a to f) State of art for modeling, chemical degradation, uncertainty

• Task 3 Review of candidate software

• Advisory Committee • Task 6

Reference cases and Model abstractions

• Task 7 Computational tool design

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Reinforced Cement Parameters at DOE Sites

OPC = Ordinary Portland Cement (Type I & II)

FA = Fly AshSF = Silica FumeBFS = Blast Furnace

Slag

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Fill/Entombment Grout Parameters at DOE Sites

OPC = Ordinary Portland Cement (Type I & II)

FA = Fly AshSF = Silica FumeBFS = Blast Furnace

Slag