ILW disposal in the UK Presentation at IAEA TM-45865, September 2013 Cherry Tweed – Chief...
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Transcript of ILW disposal in the UK Presentation at IAEA TM-45865, September 2013 Cherry Tweed – Chief...
ILW disposal in the UK
Presentation at IAEA TM-45865, September 2013
Cherry Tweed – Chief Scientific Advisor
UK Radioactive Waste
• Sources of radioactive waste– generation of electricity in nuclear power
stations– production and processing of the nuclear fuel– use of radioactive materials
• industry• medicine • research
– military nuclear programmes• Safe and appropriate management requires a
good understanding of the type and nature of the radioactive waste and materials to be managed
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• Government’s framework for managing higher activity radioactive waste through geological disposal
• NDA as implementing body committed to:– Programme of R&D– Development of RWMD into delivery
organisation– Preparation and planning for geological
disposal• Communities invited to open (without
commitment) discussions with Government– Voluntarism and partnership– Right of withdrawal
Note: Policy does not cover Scotland
Geological Disposal – UK Policy (2008)
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Schematic of ‘Single facility’ for HAW
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Baseline Timescales
Baseline Programme• First ILW waste emplacement – 2040• First HLW waste emplacement – 2075
• If added to programme, first emplacement of spent fuel from new build – 2130
• All dates are indicative. Exact timing will be agreed with host community
Illustrative geological disposal concept examples
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UK ILW/LLW Concept
Opalinus Clay Concept
WIPP Bedded Salt Concept
National LLWR Facility near Drigg
Definitions - UK
High level waste• Radioactive wastes in which the temperature may rise significantly
as a result of their radioactivity, so this factor has to be taken into account in the design of storage or disposal facilities
Intermediate-level waste• Radioactive wastes exceeding the upper activity boundaries for
LLW but which do not need heat to be taken into account in the design of storage or disposal facilities
Low-level waste• Radioactive waste having a radioactive content not exceeding 4
gigabecquerels per tonne (GBq/te) of alpha or 12 GBq/te of beta/gamma activity
UK Inventory
Pu, U and Spent Fuel are not wastes but are included in planning for geological disposal
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Material Packaged volume (m3) (2010 Baseline inventory)
HLW 6,910
ILW [1] 490,000
LLW [2] 13,800
Plutonium 7,820
Uranium 106,000
Spent Fuel 6,400
[1] Based on total volume of existing ILW stocks when packaged and future ILW arisings[2] Low level waste that cannot be disposed of at LLWR
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ILW – waste (examples)
Magnox Swarf Hulls and Ends
Legacy ponds
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Usually encapsulated in:
• Cement– BFS/OPC– PFA/OPC
Alternative processing
• Polymers (e.g. epoxy resins)• High T processing (e.g. vitrification)• Bitumen (not in UK)• Non-encapsulated (Robust shielded
containers)
ILW – conditioning process
Cutaway of cement encapsulated 500L ILW drum
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ILW – physical characteristics
Source 2010 RWI
(mass) (mass)
• ~1/3 conditioned (Packaged and or treated)
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• High activity in short-term (Cs-137, Sr-90…)
• Sharp decrease after ~ 100-1000 years,
• highly dependent on waste stream
• Activity ~order of magnitude less than HLW plot
Cs-137, Sr-90
Ni-63
Source 2010 RWI
ILW – radiological characteristics
Ni-59
Illustrative Risk Calculations – ILW concept in higher strength rock
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Some regulatory requirements
• Record keeping– Regulation require comprehensive record-keeping with duplicates
• Human intrusion – assume that human intrusion after the period of authorisation is
highly unlikely to occur– implement any practical measures that might reduce this likelihood
still further– assess the potential consequences of human intrusion after the
period of authorisation• Post-closure monitoring
– assurance of environmental safety must not depend on monitoring or surveillance
– Subsequent monitoring is not ruled out, provided it does not produce an unacceptable effect on the environmental safety case
Planned/ongoing R&D on ILW Disposal• Key radionuclides
– C-14– Uranium
• Wasteform evolution– Vitrified ILW
• Container performance– Corrosion studies
• Buffer/backfill– Long-term cement evolution
• System understanding– Nar-field component model