The Cementitious Barriers Partnership:Predicting the Long-term Chemical and Physical Performance

of Cementitious Materials used in Nuclear Applications

K. G. Brown (Presenter); CRESP, Vanderbilt U.D. Esh, M. Fuhrmann , J. Phillip; US NRC

D. Kosson, S. Mahadevan, A. Garrabrants, S. Sarkar, J. Arnold; CRESP, Vanderbilt U.H. Van der Sloot†, J.C.L. Meeussen‡, P. Seignette, R. Comans; ECN (NL)

E. Garboczi, K. Snyder, J. Bullard, P. Stutzman; NISTE. Samson, J. Marchand; SIMCO Technologies, Inc. (CA)C. Langton, G. Flach, R. Seitz, S. Marra, H. Burns; SRNL

DOE-EM Project Manager: Pramod Mallick 29 November 2011

†Hans van der Sloot Consultancy after 01JAN2010‡NRG after 01SEP2010

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Project Goal 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., up to or >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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Partnership Members• Department of Energy – Office of

Environmental Management Scenarios & Key Uncertainties Primary end-user

• Nuclear Regulatory Commission Scenarios & Key Uncertainties Primary end-user

• Savannah River National Laboratory

Performance Assessment (PA) Interface

Model Integration Cracking Scenarios Test Beds

• NIST THAMES – Microstructure Evolution &

Properties

• SIMCO Technologies, Inc. STADIUM® – Physical & Hydraulic

Performance

• Energy Research Centre of the Netherlands (w/ Nuclear Research Group, Hans van der Sloot Consultancy)

LeachXS™/ORCHESTRA – Chemical Performance & Constituent Release

• Vanderbilt University/CRESP Chemical Performance & Constituent

Release (experimental) Uncertainty Analysis Framework Model Integration

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Technical Strategy / Approach• Reference Cases – provide basis for comparison and demonstration of tools under

development Cementitious waste form in concrete disposal vault with cap Grouted high-level waste (HLW) tank closure Spent fuel pool Nuclear processing facilities closure / D&D (e.g., canyons) Grouted vadose zone to immobilize contamination Materials – surrogate low-activity waste (LAW) cementitious waste form, reducing grout,

reinforced concrete (historical), and reinforced concrete (future)

• Extension/enhancement of existing tools – CEMHYD3D/THAMES, STADIUM®, LeachXS™/ORCHESTRA, GoldSim Performance Assessment (PA) framework

• Coordinated experimental and computational program Conceptual model development and improvement Define test methods and estimate important parameters Model calibration and validation

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CBP Toolbox Development

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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 and design process

CBP Interest Area

Landfills Partnership (CRESP)Craig Benson (U of Wisconsin)

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Key Degradation Phenomena

Phenomena• Chloride ingress & corrosion• Leaching • Sulfate attack & cracking /

damage (2011)• Carbonation (2012)• Oxidation (2012)• Cracking (2013)• Pore structure relationships

with mass transfer and hydraulic properties (TBD NIST)

Integration with Conceptual Models

• Coupled degradation phenomena

• Saturated, unsaturated and variable saturation

• Liquid, vapor mass transfer

• System geometry and boundary conditions

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Specifications, Properties, and Phenomena for the Evaluation of Performance of Cementitious Barriers

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Linking Prototype Cases to Performance Models through System Abstraction

GoldSim & ASCEM

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CBP Progress and Impacts• Demonstrated coupling of LeachXS™/ORCHESTRA and

STADIUM® with GoldSim (using a Dynamic-link Library / DLL) • Understanding potential for sulfate attack during salt waste

disposal in a concrete vault• Supporting DOE-ORP Secondary Waste treatment evaluation• Participation in inter-laboratory validation of draft EPA

leaching test procedures• Data for evaluation of environmental impact of fly ash usage

in cementitious materials (grout, concrete, etc.) – input into EPA regulatory process

Software integration objectives: Provide a common, unified interface to CBP partner codes through a

GoldSim Graphical User Interface (GUI) Provide a “wrapper” for probabilistic uncertainty / sensitivity analysis

(e.g., Monte Carlo) Couple LeachXS™/ORCHESTRA,

STADIUM® and THAMES in a synergistic manner

Connect to broader systems-level performance, safety and environmental assessment models

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Impact: Comparison of Cement Data and Thermodynamic Model Predictions

1,0E-08

1,0E-07

1,0E-06

1,0E-05

1,0E-04

1,0E-03

1,0E-02

1 2 3 4 5 6 7 8 9 10 11 12 13 14

Conce

ntr

ati

on (m

ol/

l)

[Al+3] as function of pH

0,0001

0,001

0,01

0,1

1

1 2 3 4 5 6 7 8 9 10 11 12 13 14

[Ca+2] as function of pH

1,0E-06

1,0E-05

1,0E-04

1,0E-03

1,0E-02

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

[H4SiO4] as function of pH

1,0E-09

1,0E-08

1,0E-07

1,0E-06

1,0E-05

1,0E-04

1,0E-03

1,0E-02

1,0E-01

1 2 3 4 5 6 7 8 9 10 11 12 13 14

Conce

ntr

ati

on (m

ol/

l)

pH

[Mg+2] as function of pH

Mortar CEM V/A GBFS-CFA

LXS model CEMV/A

CBP concrete VU 2009

1,0E-09

1,0E-08

1,0E-07

1,0E-06

1,0E-05

1,0E-04

1,0E-03

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

[Fe+3] as function of pH

1,0E-06

1,0E-05

1,0E-04

1,0E-03

1,0E-02

1,0E-01

1 2 3 4 5 6 7 8 9 10 11 12 13 14

[SO4-2] as function of pH

Experimental data from USEPA Draft Method 1313

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Impact: Uncertainty Reduction via Calibrationof Thermodynamic Model Parameters

Prior Best Fit

Most prominent changes: Stratlingite, hydrogarnet and ettringite

Al

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Impact: Influence of Cement Type on DamageEttringite and Gypsum Profiles Damage Fronts

• Damage depends on both ettringite and gypsum formation; primary damage observed from ettringite for Type I and from gypsum for Type V cements.

0 0.005 0.01 0.015 0.02 0.0250

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

Depth (m)

Vol

ume

(m3 /m

3 of

mat

eria

l)

Ettringite (Type I)

Gypsum (Type I)

Ettringite (Type V)

Gypsum (Type V)

0 0.005 0.01 0.015 0.02 0.0250

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Depth (m)

Dam

age

para

met

er

Type IType V

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CBP Example Problem: Salt Waste Disposal System Integrity

Summary of Results for Sulfate Attack • Ability to model sulfate attack and resulting damage based on concrete

type (cement type, physical properties) and external sulfate concentration

• Probabilistic analysis for both model and parameter uncertainty

• Resulting models and parameters can be used for evaluation of a range of similar materials and scenarios

Impact• Allows selection of design parameters and materials to insure long-

term durability and meeting performance goals

• Results can be integrated into existing performance assessment fate and transport models

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Sulfate Attack Modeling1. Transport of ions (saturated porous activity gradients)

• Driven by concentration and chemical activity gradients

2. Chemical Reactions• Calculation of liquid-solid equilibrium and solid phase distribution

using LeachXS/ORCHESTRA

3. Cracking• Continuum damage mechanics model (Tixier and Mobasher, 2003)

4. Effect of cracking on diffusivity• Relationships derived from fracture mechanics and numerical

simulations (Krajcinovic et al., 1992)

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Sulfate Attack Modeling FrameworkDiffusion of Ions Leaching out of Ions

Chemical Reactions

Volume Change

Change in Porosity Strain

Cracking

Damage Parameter

Change in Diffusivity

Damage Assessment-Elastic Properties-Strength

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Sulfate Attack – Probability of Complete Damage (Example Case)

Complete damage (failure criteria): Time required for cracks to propagate through the entire structure

Time to complete damage (years)

Percentiles

Case 1S = 250 mM

Case 2S = 120 mM

Case 3S = 56 mM

5th 78 109 338

25th 186 318 772

50th 285 508 1,135

75th 513 835 1,849

95th 1,886 4,354 6,120

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CBP Example Problem: CO2 and O2 Ingress3-Layer Reference Scenario

Salt waste form(1)

Concrete(2)

Soil(3)

1000 cm 20 cm 50 cm

CO2

O2

• 3-Layer, 1-D diffusion model for reactive substances

• CO2 and O2 influx in soil layer proportional to partial pressure difference air-soil.

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CO2 Ingress & Carbonation Modeling for Tank Integrity and Closure Scenarios

All CBP Partners Provide Unique Data Sources

SIMCO Tech., Inc.experimental results for validation

LEAF Leaching Methods

Method 1313 – Liquid-Solid Partitioning as a Function of Eluate pH using a Parallel Batch Procedure

Method 1314 – Liquid-Solid Partitioning as a Function of Liquid-Solid Ratio (L/S) using an Up-flow Percolation Column Procedure

Method 1315 – Mass Transfer Rates in Monolithic and Compacted Granular Materials using a Semi-dynamic Tank Leaching Procedure

Method 1316 – Liquid-Solid Partitioning as a Function of Liquid-Solid Ratio using a Parallel Batch Procedure

Note: Incorporation of these methods into SW-846 is ongoing; titles and method identification numbers are subject to change.

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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.,

up to or >100 years for operating facilities and > 1000 years for waste management).

CBP Goal

Cementitious waste form in concrete disposal vault with cap (↔ Landfills Partnership)

Grouted high-level waste (HLW) tank closure Spent nuclear fuel pool integrity Nuclear processing facilities closure / D&D Grouted vadose zone to immobilize contamination Materials – surrogate low-activity waste (LAW)

cementitious waste form, reducing grout, reinforced concrete (historical) and reinforced concrete (future)

Example Uses and Reference Cases

Mechanistic / Phenomenological Basis

Parameter Estimation and Measurement

Boundary Conditions (physical, chemical interfaces)

Uncertainty Characterization

Basic Elements of the Performance Evaluation

Long-term Structural,

Hydraulic & Chemical

Performance of Cementitious Materials &

Barriers

Being Completed

CBP Coordinated Experimental and Computational Program Develop and improve conceptual models Define test methods and estimate important parameters Calibrate and validate models and perform probabilistic analyses

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FY2012 CBP Focus• End-user licensing and training

• High-level waste (HLW) tank integrity and closureCarbonation rate as key to external attack

• ASCEM source term demonstration case

www.CementBarriers.org For further information and reports