T. Rothfuchs, W. Bollingerfehr; W. Bechthold: Lessons learned at Asse
EURADWASTE ’04: Sixth European Commission Conference on Management and Disposal of Radioactive Waste29 March – 1 April 2004, Luxembourg
Lessons Learned from Large-Scale Experiments at the Asse Mine
GermanyTilmann Rothfuchs
Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) mbHBraunschweig/Germany
W. BollingerfehrDBE TECHNOLOGY GmbH
Peine/Germany
W. BechtholdForschungszentrum Karlsruge
Germany
T. Rothfuchs, W. Bollingerfehr; W. Bechthold: Lessons learned at Asse
EURADWASTE ’04: Sixth European Commission Conference on Management and Disposal of Radioactive Waste29 March – 1 April 2004, Luxembourg
Structure of Presentation
Introduction: German Concept on HLW Disposal
Overview of Large-Scale Experiments/Tests at Asse Mine/Germany
Detailed Results of Asse Experiments
Conclusions
T. Rothfuchs, W. Bollingerfehr; W. Bechthold: Lessons learned at Asse
EURADWASTE ’04: Sixth European Commission Conference on Management and Disposal of Radioactive Waste29 March – 1 April 2004, Luxembourg
Introduction In Germany two types of heat generating
high-level radioactive waste (HLW) have to be disposed in an underground repository:
(a) steel canisters containing vitrified fission products remaining from spent fuel reprocessing
(b) Pollux steel casks containing non-reprocessed Spent Fuel assemblies
About 30 years ago, salt formations have been selected to host a repository for all kinds of radioactive waste
disposal drift
HLW disposalboreholes
salt backfill
waste canister
T. Rothfuchs, W. Bollingerfehr; W. Bechthold: Lessons learned at Asse
EURADWASTE ’04: Sixth European Commission Conference on Management and Disposal of Radioactive Waste29 March – 1 April 2004, Luxembourg
Introduction Continued
The "Gorleben" salt dome has been investigated since 1979
In 1998, the German government expressed certain doubts with respect to the suitability of salt as host rock in general and of the Gorleben site in particular
All exploration activities were halted by the end of 2000
A moratorium was imposed for three to ten years
New formation-independent site selection criteria have been developed in order to identify alternative sites with favourable geological settings
URL research has been started 30 years ago in the Asse mine
T. Rothfuchs, W. Bollingerfehr; W. Bechthold: Lessons learned at Asse
EURADWASTE ’04: Sixth European Commission Conference on Management and Disposal of Radioactive Waste29 March – 1 April 2004, Luxembourg
Salt Deposits in Northern Germany
Gorleben
Asse
Hamburg
Hanover
T. Rothfuchs, W. Bollingerfehr; W. Bechthold: Lessons learned at Asse
EURADWASTE ’04: Sixth European Commission Conference on Management and Disposal of Radioactive Waste29 March – 1 April 2004, Luxembourg
Asse salt mine Shaft sinking 1906 -1908 Salt mining 1908 – 1964 Testing of radioactive waste disposal 1967 – 1978
Underground research laboratory 1978 - Backfilling and closure
1994 - 2012
T. Rothfuchs, W. Bollingerfehr; W. Bechthold: Lessons learned at Asse
EURADWASTE ’04: Sixth European Commission Conference on Management and Disposal of Radioactive Waste29 March – 1 April 2004, Luxembourg
Underground HLW Testing at the Asse Mine
Test/Experiment Period
Temperature Test 1-3 1967 - 1976
Temperature Test 4 1978 - 1979
Temperature Test 5 1982-1983
Temperature Test 6 1985
Brine Migration Test 1983 - 1985
Test Disposal of Highly Radioactive Radiation Sources (abandoned) 1988 – 1993
DEBORA-Project (Development of Seals for HLW disposal boreholes)
1991 – 1995 (Phase I)1996 – 1999 (Phase II)
Thermal Simulation of Drift Emplacement (TSDE)
Post Test Analysis of the TSDE experiment
1990 – 2000
2000 - 2004
T. Rothfuchs, W. Bollingerfehr; W. Bechthold: Lessons learned at Asse
EURADWASTE ’04: Sixth European Commission Conference on Management and Disposal of Radioactive Waste29 March – 1 April 2004, Luxembourg
Thermal Simulation of Drift Emplacement (TSDE)
T. Rothfuchs, W. Bollingerfehr; W. Bechthold: Lessons learned at Asse
EURADWASTE ’04: Sixth European Commission Conference on Management and Disposal of Radioactive Waste29 March – 1 April 2004, Luxembourg
TSDE Objectives
to improve the understanding of backfill consolidation behaviour in a repository in rock salt
to increase the data base on important phenomena and processes in the repository
to develop further the computer codes and material models required for long-term safety analyses
T. Rothfuchs, W. Bollingerfehr; W. Bechthold: Lessons learned at Asse
EURADWASTE ’04: Sixth European Commission Conference on Management and Disposal of Radioactive Waste29 March – 1 April 2004, Luxembourg
TSDE: Comparison of Measured and Predicted Data(2D-Modelling in 1990)
Temperature
Drift Convergence
T. Rothfuchs, W. Bollingerfehr; W. Bechthold: Lessons learned at Asse
EURADWASTE ’04: Sixth European Commission Conference on Management and Disposal of Radioactive Waste29 March – 1 April 2004, Luxembourg
Determination of remaining porosity and permeability in the compacted crushed salt backfill
Investigation of the Excavation Disturbed Zone around the test drifts
Post-test inspection and recalibration of measuring instruments
Collection of data for improvement of computer models to predict and assess host rock and backfill behaviour in the TSDE experiment and in a HLW repository
Post-test investigation of corrosion specimens
Objective of TSDE Post-Test Investigations
Determination of the status of crushed salt backfill, host rock and instruments at termination of the experiment including in detail:
T. Rothfuchs, W. Bollingerfehr; W. Bechthold: Lessons learned at Asse
EURADWASTE ’04: Sixth European Commission Conference on Management and Disposal of Radioactive Waste29 March – 1 April 2004, Luxembourg
Uncovering of the TSDE Test Field Using a Front Loader
Post Test Investigations in the TSDE Test Field
T. Rothfuchs, W. Bollingerfehr; W. Bechthold: Lessons learned at Asse
EURADWASTE ’04: Sixth European Commission Conference on Management and Disposal of Radioactive Waste29 March – 1 April 2004, Luxembourg
Core Drilling Machine at Cross Section I1
Post Test Investigations in the TSDE Test Field
T. Rothfuchs, W. Bollingerfehr; W. Bechthold: Lessons learned at Asse
EURADWASTE ’04: Sixth European Commission Conference on Management and Disposal of Radioactive Waste29 March – 1 April 2004, Luxembourg
Core K4
Post Test Investigations in the TSDE Test Field
T. Rothfuchs, W. Bollingerfehr; W. Bechthold: Lessons learned at Asse
EURADWASTE ’04: Sixth European Commission Conference on Management and Disposal of Radioactive Waste29 March – 1 April 2004, Luxembourg
Backfill Settling Measuring Device at D1-1
Post Test Investigations in the TSDE Test Field
T. Rothfuchs, W. Bollingerfehr; W. Bechthold: Lessons learned at Asse
EURADWASTE ’04: Sixth European Commission Conference on Management and Disposal of Radioactive Waste29 March – 1 April 2004, Luxembourg
Post Test Investigations in the TSDE Test Field
Convergence Measuring Rod at CS B+1
T. Rothfuchs, W. Bollingerfehr; W. Bechthold: Lessons learned at Asse
EURADWASTE ’04: Sixth European Commission Conference on Management and Disposal of Radioactive Waste29 March – 1 April 2004, Luxembourg
TSDE: Comparison of Measured and Predicted Data(Improved 3D-Modelling in 2003)
01.01.1990 01.01.1992 01.01.1994 01.01.1996 01.01.1998 01.01.200030
60
90
120
150
180
210
Exp. Calc. Sec. A-A Heater surface B-B Pillar wall B-B Roof A-A 1.2 m below drift A-A 5.0 m below drift
Tem
per
atu
re
[ °C
]
Time
Temperature
Drift Convergence
01.01.1990 01.01.1992 01.01.1994 01.01.1996 01.01.1998 01.01.20000,0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
ExperimentPhase II: 3D
DBE
Co
nv
erg
en
ce
[
m ]
Time
T. Rothfuchs, W. Bollingerfehr; W. Bechthold: Lessons learned at Asse
EURADWASTE ’04: Sixth European Commission Conference on Management and Disposal of Radioactive Waste29 March – 1 April 2004, Luxembourg
Overview of Codes and Constitutive Models Used in TSDE
Institution Code Const. Model Remarks
BGR DJIFE (3D) Heemann (2003) full 3D
DBE FLAC3D Hein (1991) full 3D
NRG MARC Hein (1991) full 3D
UPC Code_Bright Olivella-Gens full 3D
FZKFAST-BEST
ADINA, MAUS Hein (1991)3D Temperature2D Stress-Strain
G.3S ANTHYC G.3S3D Temperature2D Stress-Strain
IfG FLAC2D IfG 2D
T. Rothfuchs, W. Bollingerfehr; W. Bechthold: Lessons learned at Asse
EURADWASTE ’04: Sixth European Commission Conference on Management and Disposal of Radioactive Waste29 March – 1 April 2004, Luxembourg
Investigation of EDZ in the TSDE test Field
All permeability values determined from the four measurements were in the order of 10-22 m2.
This value represents a completely healed EDZ
Modelling of EDZ generation was fine, but modelling of healing failed
(Olivella, 2003)
T. Rothfuchs, W. Bollingerfehr; W. Bechthold: Lessons learned at Asse
EURADWASTE ’04: Sixth European Commission Conference on Management and Disposal of Radioactive Waste29 March – 1 April 2004, Luxembourg
Corrosion Investigations
280 specimens distributed in the test field on container surfaces and in the backfill
Materials considered: Ti99.8-Pd, Hastelloy C4 and C22, Cr-Ni steels 1.4306 and 1.4833
T. Rothfuchs, W. Bollingerfehr; W. Bechthold: Lessons learned at Asse
EURADWASTE ’04: Sixth European Commission Conference on Management and Disposal of Radioactive Waste29 March – 1 April 2004, Luxembourg
confirm that the alloy Ti99.8-Pd and the unalloyed/low-alloyed steels have a high resistance to general and pitting corrosion. Therefore, they are very promising materials for the manufacturing long-lived containers for the disposal of HLW/spent fuel in rock salt.
show that materials Hastelloy C4 and C22, cast iron and the Cr-Ni steels 1.4306 and 1.4833 exhibited a good corrosion resistance to general and local corrosion under the conditions of the TSDE experiment. However, it is well known from previous investigations that under some severe conditions (e.g., low pH, very high Cl-content of the brine, presence of strong oxidants), these materials suffer from pitting corrosion and/or intergranular corrosion.
Corrosion Investigations Results
T. Rothfuchs, W. Bollingerfehr; W. Bechthold: Lessons learned at Asse
EURADWASTE ’04: Sixth European Commission Conference on Management and Disposal of Radioactive Waste29 March – 1 April 2004, Luxembourg
The DEBORA Project Backfill behaviour in disposal
boreholes, especially in borehole sealsbetween the canister stack and the disposal drift
Salt Concrete Seal
Crushed Salt
- 13975
- 14225
r=1.1 m
Gas InjectionPipe
DRIFT FLOOR (without paving)
Gas Collection Volume(Alumina Beads)
Heater Elements1 and 2
- 13475
- 7975
- 7475
- 6475
- 11225
- 10225
- 7225
600
1000
1600
- 3925
- 75
Heater BoreholeTest Borehole
Heater Elements3 and 4
- 0
- 13705
+ 470
+ 1380
Gas Injection Volume
T. Rothfuchs, W. Bollingerfehr; W. Bechthold: Lessons learned at Asse
EURADWASTE ’04: Sixth European Commission Conference on Management and Disposal of Radioactive Waste29 March – 1 April 2004, Luxembourg
Results of DEBORA 2Material models confirmed by good agreement of measurements and predictions
0,0
20,0
40,0
60,0
80,0
100,0
120,0
140,0
160,0
22. Sep 97
31. Dez 97
10. Apr 98
19. Jul 98
27. Okt 98
4. Feb 99
15. Mai 99
23. Aug 99
Tem
pe
ratu
re /
°C
Calc. Hein's Param., 10.1 mCalc. Hein's Param., 12.1 mCalc. Hein's Param., 14.1 mCalc. GRS Param., 10.1 mCalc. GRS Param., 12.1 mCalc. GRS Param., 14.1 mMeasurement 10.1 mMeasurement 12.1 mMeasurement 14.1 m
Temperature development in the backfilled borehole of DEBORA 2
Porosity development in the backfilled borehole of DEBORA 2
0,00
0,05
0,10
0,15
0,20
0,25
0,30
0,35
0,40
22 Sep 97
31 Dez 97
10 Apr 98
19 Jul 98
27 Okt 98
4 Feb 99
15 Mai 99
23 Aug 99
Po
ros
ity
/ -
Calc. Hein's Param., 10.1 mCalc. Hein's Param., 12.1 mCalc. Hein's Param., 14.1 mCalc. GRS Param., 10.1 mCalc. GRS Param., 12.1 mCalc. GRS Param., 14.1 mMeasurement 10.1 mMeasurement 12.1 mMeasurement 14.1 m
T. Rothfuchs, W. Bollingerfehr; W. Bechthold: Lessons learned at Asse
EURADWASTE ’04: Sixth European Commission Conference on Management and Disposal of Radioactive Waste29 March – 1 April 2004, Luxembourg
Results of DEBORA 2
Porosity/permeability relation obtained from DEBORA
confirms older laboratory results of various investigators(Müller-Lyda et a.,1999)
DEBORA 8 mm
k = 1.12 . 10-8 5.25
DEBORA 30 mm
k = 6.7 . 10-112.64
1,E-18
1,E-17
1,E-16
1,E-15
1,E-14
1,E-13
1,E-12
1,E-11
1,E-10
0,01 0,1 1porosity [-]
Per
mea
bili
ty K
[m
2 ]DEBORA 8 mm
DEBORA 30 mm
TSDE In-Situ Test Value
TSDE Post Test Data I
TDSE Post Test Data II
TDSE backfill
k = 8 . 10-11 2.5
T. Rothfuchs, W. Bollingerfehr; W. Bechthold: Lessons learned at Asse
EURADWASTE ’04: Sixth European Commission Conference on Management and Disposal of Radioactive Waste29 March – 1 April 2004, Luxembourg
The HAW project: Transient emplacement of 30 highly radioactive radiation sources (Cs-137+ Sr-90) in the Asse mine
Planned to be performed in the 8ties and 9ties of the last century
Project stopped in 1992
Two heater test operated over 5 years
Development and testing of a transport and emplacement system for HLW canisters
T. Rothfuchs, W. Bollingerfehr; W. Bechthold: Lessons learned at Asse
EURADWASTE ’04: Sixth European Commission Conference on Management and Disposal of Radioactive Waste29 March – 1 April 2004, Luxembourg
Arrangement of Test Boreholes in the Test Field at the 800-m Level in the Asse mine
T. Rothfuchs, W. Bollingerfehr; W. Bechthold: Lessons learned at Asse
EURADWASTE ’04: Sixth European Commission Conference on Management and Disposal of Radioactive Waste29 March – 1 April 2004, Luxembourg
Development and Testing of a Transport and Emplacement System for High-Level Radioactive Waste Canisters
Emplacement of radioactive canisters never realized
System, however, successfully tested without radioactive material
System approved by the responsible mining authority
Extremely valuable experiences for the operation of a HLW repository in salt formations
T. Rothfuchs, W. Bollingerfehr; W. Bechthold: Lessons learned at Asse
EURADWASTE ’04: Sixth European Commission Conference on Management and Disposal of Radioactive Waste29 March – 1 April 2004, Luxembourg
Conclusions
The three large-scale experiments performed in the Asse mine yielded most important data for the validation of material and computer models needed to assess the coupled thermo-hydro-mechanical long-term behaviour of rock salt and crushed salt backfill in a repository in geological salt formations
2D-Modelling was found inadequate to simulate complex experiment geometries. If end-effects are to simulated adequately, as in the TSDE experiment, full 3D-modelling is required
Post-test investigations of host rock, backfill and recalibration of measuring instruments were extremely useful for the confirmation of applied models and measuring techniques
A complete transport and emplacement system was developed and successfully tested in the framework of the HWA-project. Although such a system will certainly be designed differently on basis of advanced technologies in about 20 to 30 years when a repository will be taken into operation, the exercises at Asse mine demonstrated the principle availability of the techniques for the safe handling of HLW canisters
T. Rothfuchs, W. Bollingerfehr; W. Bechthold: Lessons learned at Asse
EURADWASTE ’04: Sixth European Commission Conference on Management and Disposal of Radioactive Waste29 March – 1 April 2004, Luxembourg
Acknowledgements
The work was co-funded by the national governments and authorities and by the European Commission. The authors would like to thank for this support. Special thanks also to all project partners (ANDRA, BGR, DBE, DOE-CBFO, ECN, ENRESA, FZK, G.3S, GSF, IfG, NRG, UPC) for their continuous support and the fruitful discussions in the many project meetings.
BAMBUS II Project Committee on August 31, 2000
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