Experience in developing LLW disposal facilities in France How to deal with continuous changes?

Transcription

1 Experience in developing LLW disposal facilities in France How to deal with continuous changes? Michel DUTZER, Sylvie Voinis Andra the Safe Disposal of Low Level Radioactive Waste Paris- 3-5 February 2015

2 The present safety approach is the result of continuous changes Changes in guidance and regulations IAEA Europe National French regulation Changes in technologies Changes in needs Changes in social expectations Improvement of knowledge Scientific knowledge Lessons learnt from existing facilities Disposal facilities have to face these changes: For a few decades in operation, For a few centuries in the institutional control period

3 The French approach takes into account the experience of Centre de la Manche 25 years of operation : ,000 m 3 of waste packages disposed of License for the institutional control period: years of institutional control (the beginning of a long story) From operation to closure and to institutional control

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5 and of Centre de l Aube Construction license: 1989 Start up: 1992 Capacity: 1,000, 000 m 3 Initial design for operational waste ( m 3 /year). Initially forecast for 30 years of operation Volume disposed of : m 3 (end 2014) Centre de la Manche Centre de l Aube To 60 years of operation A facility that should accommodate operational waste and decommissioning waste from existing or already decided facilities

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7 but also of the very low level waste disposal facility of CIRES License: 2003 Capacity: 650,000 m3 2 km Disposed volume: m 3 (end 2014) Planned for 30 years of operation

8 The development of safety principles 1969: simple principles in the license of Centre de la Manche one barrier: package or vault Intermediate level waste > 1000 MCDW (maximum concentration in drinking water) Concrete blocks or grouted cells Improvement taking into account experience => safety guides (1984) Safety guide 1.2: general principles Multi-barrier system Management phases» Short term and long term safety Safety guide 3.2.e: conditioning principles Containment requirements Guides used for the design of Centre de l Aube and still applicable

9 Basic safety principles Operation Institutional control period (no more than 300 years) Functions Short term safety Post institutional control period Assuming a loss of memory No significant hazard Long term safety

10 Improvement of knowledge A feed-back from Centre de la Manche to Centre de l Aube Minimization of effluents during operation Centre de la Manche: operated in the open air Centre de l Aube: mobile shelters Long lived emitters limitations Alpha emitters < 370 Bq/g (mean value) Restrictions for radium bearing wastes (radon in the monitoring gallery) A cautious approach of tritiated wastes Centre de la Manche : a contamination by tritium in the groundwater and in the rivers Maximum: Bq/l in the river not a safety issue, Wastes removed Plume propagation in the groundwater Present hypothetical impact: 0.3 µsv/year, Contamination decreasing However still a communication issue Centre de la Manche % Volume LL radionuclides Time Centre de l Aube: follow up of capacity Centre de l Aube Monitoring gallery Safe does not always mean acceptable Plume at the source of a river

11 A feed-back from Centre de la Manche to Centre de l Aube Maintaining memory Keeping memory as long as achievable: A synthetic memory 1 report of 170 pages Assessed by the local information commission A detailed memory More than documents more than pages Assessed by national and international review panels Implementation of preservation long term records performed at Centre de l Aube

12 Improvement of knowledge :demonstrability of safety concepts Example of the capping system: scientific studies Experimental clay capping system (Centre de l Aube) Studies on ageing of the bituminous membrane (Centre de la Manche) Investigation and remediation on site (Centre de la Manche) Development of flora on site (Centre de la Manche) Periodical progress reports

13 Improvement of knowledge :demonstrability of safety concepts Water transfer model Periodical re-assessment of the hydrodynamic model (Centre de l Aube)

14 Changes in technology Tools for a better follow up of the radiological content Since

15 Improvement of knowledge Characterization of the radioactive content of wastes In the 1960 ties a few radionuclides to be addressed Presently a rather comprehensive list of 144 radionuclides that are potentially present in wastes and that are to be assessed during the acceptance process A key question for long term safety of near surface disposal facilities: the long lived radioactive content A challenge: a reliable and industrial assessment: Various waste streams Decommissioning wastes

16 Defence in depth An important tool: the acceptance process 1. Waste acceptance criteria A description of the domain for waste packages (in some cases a restricted part of this domain): For which the design is valid For which the safety analysis is valid A tool to mitigate unexpected events 2. Acceptance process Prevent Mitigate Obtain confidence prior production in the waste generator s capacity to manufacture packages complying with WAC Qualification with respect to WAC Acceptance file Assessment of QA/QC in the generating facility Delivery acceptance A contract between Andra and waste generator Waste acceptance process Training Maintain confidence during production Computer checks by Andra of waste packages declared data Checks by Andra at delivery (visual, dose rate) Inspections/audits at the generators' sites Destructive and non destructive tests by Andra tests

17 Changes in needs: specific design and safety case Management of spent sealed sources General approach Identification of specific long terms hazards Dedicated long term scenarios Regulatory approval and technical prescriptions Generic acceptance criteria Heat generating Co-60 sources (under progress) Dedicated application file Handling and conditioning processes (radiation protection issues) Thermal studies

18 Changes in needs: specific design and safety case Management of large disused components Vessel heads Specific disposal design Remote handling system of a pilot reprocessing plant Specific safety case Specific acceptance criteria Specific regulatory approval Decontaminated steam generator (VLL) Fast breeder lateral neutronic shieldings

19 A need to find an overall optimization in waste management To consider all phases of waste management Waste generation Waste characterization Waste treatment Waste transportation Waste storage Waste disposal To consider different issues Regulatory and licensing issues Technical and operational issues Safety issues Economic and scheduling issues Public acceptance and stakeholders issues In accordance with ALARA principle

20 Changes in social expectations Repository Disposal facility

21 Conclusion A continuous improvement taking into account lessons learnt and changes In particular social expectations Periodical safety re-assessment: a key tool to maintain confidence To incorporate lessons learnt To incorporate new knowledge To incorporate new wastes To incorporate new designs Waste management is not only disposal The need of an overall optimization Considering all phases of waste management Dealing with different issues, including safety issues ALARA in an overall approach in the framework of a dialogue with the different actors

22 Thank you for your attention!