This document summarizes modeling work done as part of the DECOVALEX-2015 international modeling collaboration on heater experiments. It describes two heater experiments, one in Opalinus clay at the Mont Terri rock laboratory and one in siliceous mudstone at the Horonobe underground research laboratory. International modeling teams developed models of both experiments to predict thermal-hydrological-mechanical behavior during heating. The models generally captured trends like heating and drying near the heat source, with some variations. Comparisons of predictions to experimental measurements showed good agreement for temperature but smaller than predicted stresses. The collaboration provided an opportunity for model testing and development.

1. Used Fuel Disposition Campaign
DECOVALEX-2015 heater test
modeling highlights
Jonny Rutqvist, Jens Birkholzer
Lawrence Berkeley National Laboratory
UFD WG Meeting in Las Vegas
International Disposal R&D Sessions
June 8, 2016

2. Used
Fuel
Disposition
DECOVALEX-2015 Tasks related to Heater
Experiments (2012-2015)
DECOVALEX-2015 Task B1: Mont Terri HE-E experiment
in Opalinus Clay (8 international research teams)
- Step 1 Modeling HE-D heating experiment of Opalinus
Clay and THM laboratory experiment on bentonite
- Steps 2 and 3 HE-E experiment predictive modeling and
interpretative analysis
DECOVALEX-2015 Task B2: Horonobe EBS experiment
in siliceous mudstone (5 international research teams)
- Step 1 Benchmark calculation related EBS experiment for
code comparison and bentonite characterization
- Steps 2 and 3 Horonobe EBS predictive modeling and
interpretative analysis
Included up to 3 years of heating data (2011 to 2014)
Heating at Horonobe EBS started January 2015

3. Used
Fuel
Disposition
TOUGH-FLAC Model of Mont Terri HE-E Experiment
FLAC3D
Geomechanical Simulator
TOUGH
Multiphase Flow
Simulator
FLAC3D
Geomechanical Simulator
TOUGH
Multiphase Flow
Simulator
Full multphase flow (gas and
liquid ) simulations coupled
with geomechanics

4. Used
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Disposition
LBNL MODEL PREDICTION VS MEASURMENTS
Relative Humidity Temperature
Model Prediction
Measurements
4

5. Used
Fuel
Disposition
Date Presentation or Meeting Title 5
8 INTERNATIONAL MODELING TEAMS

6. Used
Fuel
Disposition
Date Presentation or Meeting Title 6
Trends of heating
and drying near heat
source is captured in
all models with some
variations
COMPARE RESULTS IN BENTONITE BUFFER
Granular Bentonite
Bentonite blocks
Granular
Bentonite
Bentonite
blocks

7. Used
Fuel
Disposition
Concrete Lining
Plug
Heater
Bentonite
Sand layer
Backfill
60m
TOUGH-FLAC Model of Horonobe EBS
Experiment
3D TOUGH-FLAC model
grid
June 10, 2015 UFD WG Meeting in Las Vegas 7

8. Used
Fuel
Disposition
Date Presentation or Meeting Title 8
5 INTERNATIONAL MODELING TEAMS

9. Used
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Disposition
Date Presentation or Meeting Title 9
20.0
30.0
40.0
50.0
60.0
70.0
80.0
0 50 100 150
Temperature（℃）
Elapsed time (day)
TE009
Thermocouple
JAEA
CAS
BGR
Inha Univ./KAERI
LBNL/DOE
Horonobe EBS Models vs Observations
(5 DECOVALEX-2015 teams)
0.00
0.05
0.10
0.15
0.20
0 20 40 60 80 100 120
Stress(MPa)
Elapsed time (day)
TP009
Pressure cell
JAEA
CAS
BGR
Inha Univ./KAERI
LBNL/DOE
Temperature
prediction good
Stress very small
after 75 days in
both data and
models (far from
fully developed
swelling)

10. Used
Fuel
Disposition
Date Presentation or Meeting Title 10
• Participating DECOVALEX-2015 provides access to
multi-million dollar, multi-year experimental data for
testing and validating models at a relevant scale
• Excellent forum for exchange of ideas and new
approaches to model complex coupled processes
• Final DECOVALEX-2015 reports of have been delivered
in May 2016
• 4 joint journal papers among international participants
are in preparation (submission June 30, 2016)
• Look forward to DECOVALEX-2019 work on heater test
data in Callovo-Oxfordian claystone (COx) at MHM URL
France
Concluding Remarks