Alternative Buffer Material

Project meeting #22006-11-30

Agenda• 09:00 Welcome and introduction

Project status.Anders Eng, Acuo Engineering

• 09:45 Block Manufacturing.Ulf Nilsson, Clay Technology

• 10:15 Coffee• 10:30 Bentonite characteristics

Dietrich Koch, IKO Minerals

• 11:15 Experiment site visit• 12:00 Lunch• 13:00 Storage (parameters, amount etc)

Anders Eng

• 13:15 Future work, analysesDaniel Svensson, SKB

• - 15:00 Discussions

Talk points

• Project outlines

• Installation

• Current status

• Future work

Talk points

• Project outlines

• Installation

• Current status

• Future work

Project goals

• Verify laboratory results with in situ studies, emphasis on temperature, scale and geochemical conditions.

• Discover possible problems with block manufacturing and handling

• Give further data for verification of thermo-hydro-mechanical (THM) and geochemical models.

International participation

• Participating organizations:• SKB• Andra• BGR• GRS• JAEA• Nagra• Posiva• RAWRA• University of Bern

Experiment design

Experiment design based on LOT experiment with some modifications:• Several materials

• Less instrumentation

• Shorter deposit holes

• Complete package length heated

• Steel pipes

• No inserts or tracers

1 2 34 m4 m

Short time (1-2 years).Heated from start.Artificial saturation from start.

Medium time (2-4 years).Heating starts when buffer is saturated.Artificial saturation from start.

Long time ( 5 years).Heated from start.No artificial saturation.

Materials

Block material:• Ikosorb• Deponit CA-N• Ibeco Seal M-90• Friedland• Asha 505• Calcigel• Febex• Kunigel V1• Callovo Oxfordian

(both discs and remoulded)• Rokle• Mx-80

Granulates:• MX-80• MX-80 with quartz

Total of 14 variations of 11 materials !

Talk points

• Project outlines

• Installation

• Current status

• Future work

Experiment site

Package design

Package parts:• Steel pipe

• Buffer blocks

• Saturation system

• Instrumentation

• Heater system

• ”Backfill”

Steel pipes

• ”Black” steel.

• Bottom plate welded to pipe.

• Welds are pressure leak tested.

• Corrosion prevention at top and bottom.

Buffer blocks

Roughly 100 blocks manufactured

• Block dimensions:– 10 cm high

– Dy = 29 cm

– Di = 11 cm

• Pressure about 100 MPa.

• Density about 2 g/cm3

• 10-12 kg each.

Granulate cage

Problem:Keep granulates in place during installation.

Used tools / materials should not interfere with experiment.

Solution: Steel granulate container.Frame will take force from blocks above.

Same material as heater pipe.

GeoTextile keep granulates in place and allows water passage.

Open at top and bottom for interaction with surrounding blocks.

Granulate cage

Granulate cage

Saturation system

System properties:• Four perforated titanium pipes in each package

• Pipes connected in pair at package bottom – flushing possible.

• 0,1 m between perforation in package 1.

• 1 m between perforations in package 2 & 3.

• Pipes protected by “plastic textile” – prevent holes from clogging with sand.

Sensors

Monitoring temperature and humidity:• Thermocouples

– 20 per package

• Temperature indicators,– 2 between each block.

• Relative humidity sensors– 4 in package number 2.

Sensors

Putting the pieces together

Talk points

• Project outlines

• Installation

• Current status

• Future work

Current status

Project status as of today:

• All three packages assembled and installed in deposit holes.

• Monitoring system completed.

• Remaining buffer blocks are in storage.

Remaining work

• Final assembly of saturation system

• Heater installation

• System startup

Talk points

• Project outlines

• Installation

• Current status

• Future work

Storage

Reference blocks is presently stored on Äspö.

• Temperature above 0°C.

• Temperature variations with season.

• Blocks wrapped in plastic bags and put in boxes.

Other parameters to consider?

• Test program – Daniel Svensson is responsible for planning from SKB side.