A review of technical options for treatment

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(No Transcript)
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Treatment options for Asbestos Wastes

• A review of technical options for treatment

Date 22nd January 2008
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Asbestos

• Asbestos is the commercial name given to
  naturally occurring fibrous silicate materials

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Asbestos Hazards

• The fibrous nature of asbestos makes it a very
  hazardous substance
• If asbestos is damaged or disturbed it can
  release fibres into the air. These fibres have a
  much smaller diameter than a human hair
• If inhaled these fibres can get deep into the
  lungs and can give rise to asbestosis and lead to
  mesothelioma a severe and usually lethal form of
  cancer

Asbestos The greatest single cause of work
related deaths in the UK HSE Website
Human hair against asbestos fibres
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Asbestos Uses
Asbestos fire blanket
Asbestos ceiling tiles
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Waste Volumes

• Significant legacy volumes of waste on the
  Sellafield site
• Some 6,000 tonnes from Calder Hall
  decommissioning
• Similar volumes from the rest of Sellafield
• Overall the decommissioning of the UK nuclear
  facilities will generate some 55,000 tonnes of
  asbestos

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Calder Hall Decommissioning
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Waste Characterisation

• Characterisation of Calder Hall asbestos shows
  approximately 90 is exempt waste and 10 low
  level waste (very low level)
• Remaining asbestos yet to be characterised
  however the bulk of it is expected to be low
  level or very low level wastes
• Exempt asbestos wastes currently being disposed
  of to a PPC licenced landfill site

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Activities
LLW usually disposed of to the repository near
Drigg
LLW
Typical Sellafield waste activity range
VLLW disposal to specified landfill
VLLW
Substances of Low Activity this material is
exempt from specific regulatory control
SoLA
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VLLW LLW Activities In Perspective
4000 Bq/g
LLW
40 Bq/g
VLLW (H3)
4 Bq/g
VLLW
SoLA max 0.4 Bq/g
50x magnification
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Treatment Disposal Options
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Direct Disposal

• Not an option for large quantities of fibrous LLW
  asbestos
• Exempt asbestos can go to suitably engineered and
  permitted landfill sites
• In the UK some 400,000 tonnes of asbestos
  contaminated material is landfilled annually

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Physical Treatment - Compaction

• Compaction process to reduce volume
• Compacted pucks placed into iso freight container
  for disposal to LLWR
• Proven technology
• Can achieve up to 8 x volume reduction factor

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Chemical Treatment

• Asbestos can be converted to a non fibrous silica
  based material by the action of acids
• A range of proprietary formulas are available
• Usually sprayed on in-situ as foams to mitigate
  against having to remove lagging
• Limited bulk application of chemical treatment
  technology

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Thermo Chemical Treatment

• Thermo Chemical Treatment Technology (TCCT)
• Process involves mixing asbestos with a fluxing
  agent heating to 1250oC
• Asbestos loses fibrous properties and becomes an
  inert silica product
• Process developed and demonstrated in the US
• Silica product can potentially be reused
• Not in full commercial use due to cheaper
  landfill options

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Vitrification Processes

• Vitrification Process
• Several variants of this process available for
  use in the treatment of asbestos wastes
• Process involves heating the asbestos to
  approximately 1500oC
• Asbestos melts and loses its fibrous properties
  becoming an inert amorphous silica
• Silica product can potentially be re-used

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Geomelt Hazardous Waste Treatment Plant
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Geomelt Hazardous Waste Treatment Plant
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Geomelt Asbestos Trials

• Tightening of waste disposal regulations in Japan
• gt43 million tonnes of asbestos wastes will
  require disposal
• Landfill space limited
• Disposal costs increasing
• Drive for volume reduction and detoxification
• Japanese Ministry of Environment evaluating
  options

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Geomelt Asbestos Trials

• ICV (In Container Vitrification) demonstration
  program for Japans Ministry of Environment
• Series of melts of asbestos waste
• Melt process destroyed fibres
• No fibres detected in glass product or in off-gas
  treatment system
• Up to 80 volume reduction
• Establishing larger treatment plant (45
  tonne/batch

Post-Melt Removal of ICV Box
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Geomelt Asbestos Trials
Treated asbestos product
Schematic showing Joule heating process
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Plasma Processes

• Formed when gas, e.g. nitrogen, is heated to over
  5,000 K
• Plasma is an ionised (electrically charged) gas
• Thermal plasma emits intense heat and UV light
• Thermal plasma arcs widely used in steel industry
• Cracks/reforms all organic matter and melts, or
  vitrifies, inorganic matter to form an inert rock

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Europlasma Asbestos Plant
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Financial

• Relatively small volumes of contaminated
  Sellafield waste make it difficult to demonstrate
  a viable business case to support development of
  a destruction process
• Construction costs of a thermal process in the
  region of 10M
• Disposal charges to existing landfill sites
  approx 250 per tonne
• Characterisation of UK Nuclear Industry asbestos
  is likely to be similar to Sellafield data
• Potential option to develop a combined process
  with other small volume LLW arisings

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Questions?