Docstoc

Title of presentation pt Arial Bold

Document Sample
Title of presentation pt Arial Bold Powered By Docstoc
					Developing the LLWR’s
Environmental Safety Case
Dr Richard Cummings
LLWR ESC Project Manager

Date: 20th May 2010




                           2010 Customer Forum
Presentation

•   What is an ESC?
•   Project history and importance
•   Examples of progress over last year
•   Implications for Waste Acceptance Criteria
•   Timescales for new authorisation for disposal




                                               2010 Customer Forum
What is an ESC?




              2010 Customer Forum
Definition of an ESC

• “The collection of arguments, provided by the
  developer or operator of a disposal facility, that seeks
  to demonstrate that the required standard of
  environmental safety is achieved”




                                               2010 Customer Forum
GRA

•   GRA: Near-surface Disposal
    Facilities on Land for Solid
    Radioactive Waste - Guidance
    on Requirements for
    Authorisation

•   Revised GRA issued February
    2009

•   132 pages

•   5 Principles and 14
    Requirements


                                   2010 Customer Forum
GRA Principles

1. Level of protection against radiological hazards at
   the time of disposal and in the future
2. Optimisation (ALARA)
3. Level of protection against non-radiological hazards
   at the time of disposal and in the future
4. Reliance on human action
5. Openness and inclusivity



                                             2010 Customer Forum
GRA Requirements

1.   Process by agreement                  8. Optimisation
2.   Dialogue with local communities       9. Environmental radioactivity
     and others                            10. Protection against non-radiological
3.   Environmental safety case                 hazards
4.   Environmental safety culture and      11. Site investigation
     management system                     12. Use of site and facility design,
5.   Dose constraints during the period        construction, operation and closure
     of authorisation                      13. Waste acceptance criteria
6.   Risk guidance level after period of   14. Monitoring
     authorisation
7.   Human intrusion after period of
     authorisation




                                                                   2010 Customer Forum
The challenge

• Must address post-
  authorisation phase – 1000+
  years in future
• Long-term safety must be
  passive - cannot rely on
  future human action
• Levels of protection in the
  future same as now
• Risk guidance level of one in
  a million per year



                                  2010 Customer Forum
Project History and Importance




                       2010 Customer Forum
Current Authorisation and Planning Permission


• Last ESC submitted 2002

• Not accepted by EA

• 2006 Authorisation only allows disposal until Vault 8 full

• Planning permission for Vault 9 only allows storage

• Future of LLWR depends on successful ESC



                                                        2010 Customer Forum
LLWR Response

• New project set up in 2006

• Project re-planned and costed in 2008 when new
  PBO took over

• New PM and team




                                          2010 Customer Forum
Project Schedule

• Data freeze/ready for final assessment milestone 1st May 2010
• Revised ESC required by EA by 1st May 2011


 Project Phases                   Timings
 Planning                         April – September 2008
 Development Phase 1              October 2008 – March 2009
 Development Phase 2              April 2009 – April 2010
 Execution                        From May 2010



                                                     2010 Customer Forum
Regulatory Liaison

• Liaising closely with Environment Agency to ensure
  2011 ESC meets their requirements

• For example:
   – Monthly Project progress and technical liaison meetings
   – Methodology notes exchanged
   – Discussions with EA policy team




                                                  2010 Customer Forum
Examples of Progress Over
       Last year



                    2010 Customer Forum
2011 ESC Documentation

• Started to plan and develop

• 17 top-level documents, ~1600 pages

• Hundreds of key underpinning documents




                                           2010 Customer Forum
ESC Documentation Concept


• Level 1 - The ESC
   – presents the safety arguments
                                      Arguments

• Level 2 - ESC topic reports
   – present the evidence,            Evidence
     evaluations etc.


• Level 3 - supporting reports
   – technical and external reports     Basis




                                                 2010 Customer Forum
Improvements to Inventory

• „Recall‟ exercise – assessing implications

• Using most up-to-date data for future disposals –
  Widram 09

• Have been working with consignors on accuracy of
  data for key radionuclides and wastestreams



                                               2010 Customer Forum
Source-term

• Developing NNL „General Repository Model‟

• Models:
    – Evolution of chemical environment (pH, Eh)
    – Behaviour of U
    – Release of C-14 to gas and groundwater pathways

• Effects of heterogeneity in waste disposals

• Experimental studies of U release and sorption


                                                        2010 Customer Forum
Stage 6 Boreholes

• 14 off-site boreholes drilled
• Close liaison with
  environmental regulators to
  ensure SSSI protected
• Innovative approaches
  reduced impact and saved
  money
• Data being used to revise
  geological and
  hydrogeological models




                                  2010 Customer Forum
Hydrogeological Modelling

• Better calibrated
  hydrogeological model of
  repository and locality
  developed




                             2010 Customer Forum
Optimisation of Engineering Design

• Current design




                                     2010 Customer Forum
Optimisation of Engineering Design

• Iterative and evidence-based

•   Single dome cap – more resilient to erosion
•   Vault design changed to reduce „bath-tubbing‟
•   No need for drains
•   Depth of cut-off walls reduced

• Better overall environmental performance for less
  cost
                                              2010 Customer Forum
Reduced Cut-off Wall Depth




                             2010 Customer Forum
New Vault Design




                   2010 Customer Forum
Coastal Erosion Studies




                          2010 Customer Forum
Improvement to Assessment Methodologies

• Assessments:                   • Wells assessment:
   –   Groundwater pathway          –   Inventory key radionuclides
   –   Non-radiological impact      –   Kinetic source-term models
   –   Non-human species            –   Probability
   –   Gas assessment               –   Type of well (dilution)
   –   Coastal erosion              –   Exposed groups
   –   Human intrusion




                                                     2010 Customer Forum
Implications for Waste
 Acceptance Criteria



                   2010 Customer Forum
Current LLWR WAC

•   Radiological limits:
     – Specific activity limits based on
       definition of LLW
     – Annual limits for key
       radionuclides based on 1988
       NRPB assessment

•   Other criteria developed in an ad
    hoc way

•   Have been reviewed in recent years
    to provide reassurance that they are
    sufficiently protective

•   Not derived from an accepted safety
    case



                                           2010 Customer Forum
Revised LLWR WAC

• There will be new WAC rigorously derived from 2011 ESC

• Ideas developing – not discussed yet with EA

• More flexible

• Radiological limits:
    – Retain 4 and 12 GBq/te
    – Manage overall capacity of repository for key radionuclides –
      complex process but transparent to consignors
    – Trigger levels rather than annual limits


                                                         2010 Customer Forum
Timescales for New Authorisation
          for Disposal




                         2010 Customer Forum
Future timescales

• Revised ESC submitted by 1st May 2011

• EA review of ESC completed and new authorisation
  for disposal by 31st March 2013 (LLWR target)

• I.e. two vs. four years last time




                                          2010 Customer Forum
Summary




          2010 Customer Forum
Summary

• On-going work programme to obtain authorisation for
  disposal in 2013

• Close liaison with EA

• New WAC based on 2011 ESC




                                           2010 Customer Forum

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:3
posted:9/15/2011
language:English
pages:33