The Cementitious Barriers Partnership:

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
; NIST

E. 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

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

2

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



3

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

4

CBP Toolbox Development

5

Integration of CBP Tools with PAs

Atmosphere
Soil layers
Cap layers
Source
Vadose Zone
(
s
)
Saturated Zone
(
s
)
Surface Water
Engineered
System
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)

6

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

7

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

8

Linking Prototype
Cases to
Performance
Models through
System
Abstraction

GoldSim & ASCEM

9

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

10

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

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
Concentration (mol/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
Concentration (mol/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

13

Impact:
Uncertainty
Reduction
via Calibration

of Thermodynamic Model Parameters

Prior

Best Fit

Most prominent changes:
Stratlingite
,
hydrogarnet

and ettringite

Al

14

Impact: Influence
of Cement Type on Damage

Ettringite

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
0.025
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
Depth (m)
Volume (m
3
/m
3
of material)


Ettringite (Type I)
Gypsum (Type I)
Ettringite (Type V)
Gypsum (Type V)
0
0.005
0.01
0.015
0.02
0.025
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Depth (m)
Damage parameter


Type I
Type V
15

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

16

Sulfate Attack Modeling

1.
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)

17

Sulfate Attack Modeling Framework

Diffusion 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

18

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 1

S = 250
mM


Case 2

S = 120
mM

Case 3

S = 56
mM

5
th


78

109

338

25
th

186

318

772

50
th

285

508

1,135

75
th

513

835

1,849

95
th


1,886

4,354

6,120

19

CBP Example Problem: CO
2

and
O
2

Ingress

3
-
Layer Reference Scenario

Salt

waste form

(1)

Concrete

(2)

Soil

(3)

1000 cm

20 cm

50 cm

CO
2

O
2

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

•
CO
2

and O
2

influx in soil layer
proportional
to partial pressure
difference air
-
soil.



20

CO
2

Ingress & Carbonation Modeling for

Tank Integrity and Closure
Scenarios

All CBP Partners
Provide Unique

Data
Sources

SIMCO Tech., Inc.

experimental results
for validation

21

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.

22


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

23

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

FY2012 CBP Focus

•
End
-
user licensing and training

•
High
-
level waste (HLW) tank integrity and closure


Carbonation rate as key to external attack

•
ASCEM source term demonstration case

www.CementBarriers.org


For further information and reports

24