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1. Spent Fuel and Waste Science and Technology
Collaboration with Clausthal/Germany on
coupled THM modeling
Jonny Rutqvist, Mengsu Hu, Laura Blanco-Martin, Jens Birkholzer
Lawrence Berkeley National Laboratory
SFWST WG Meeting in Las Vegas
International Session
May 24, 2017

2. Spent Fuel and
Waste Science and
Technology
Salt Coupled THM Processes – TOUGH-FLAC
 Lux/Wolters solid salt constitutive model (creep, TM damage-induced permeability
(DZ), high pressure fluid filtration, sealing, heating)
 Crushed salt constitutive model (THM properties as a function of compaction and
solidification)
 Large-strain and deformable mesh
 Brine migration, evaporation, condensation, salt precipitation etc. (THMC)

3. Spent Fuel and
Waste Science and
Technology
Based on same software
Use of different numerical schemes
TOUGH-FLAC
(Berkeley Lab)
Sequentially coupled flow-geomechanics simulators
TOUGH2 (fluid + thermal flow)
FLAC3D (geomechanics)
Can deal with large strains & creep processes
Material-specific constitutive relationships available
FLAC-TOUGH
(TU Clausthal)
Similarities
Main difference
Fixed-stress split
Undrained split
TOUGH-FLAC vs FLAC-TOUGH

4. Spent Fuel and
Waste Science and
Technology
• LBNL expertise on multiphase flow and geomechanics with TOUGH-
FLAC complemented with Clausthal expertise on salt geomechanics
and constitutive models
• New improvements implemented in both TOUGH-FLAC and FLAC-
TOUGH and benchmarked against each other
• Collaboration results presented in journal (2) and conference (5)
presentations during 2014-2016..
• International code comparison project (BenVaSim) lead by Clausthal
University focusing on “simulator benchmarking” for full THM,
including fluid flow
LBNL-Clausthal Collaboration

5. Spent Fuel and
Waste Science and
Technology
Example of LBNL-Clausthal Collaboration:
TSDE (Heater Test) Asse Mine
Code-to-code verification and validation against experimental data

6. Spent Fuel and
Waste Science and
Technology Concluding Remarks
• Mutually very beneficial collaboration resulted in great
progress in salt coupled THM modeling within a few years
• Further model improvements and benchmarking is planned
focusing on full THM coupling, including fluid migration
(BenVaSim)