IAEA ASN – Paris1 Work group 1 Outcome of the discussions Topic 2 and 3

IAEA ASN – Paris2 Topic 2 – challenges SC development How to develop and update SC Before development safety case, – Pre-assessment inventory, types and characteristics of waste (= basis) – best available knowledge – Integrate in national strategy (waste plan, policies...) and in view of application of graded approach

IAEA ASN – Paris3 Topic 2 – challenges SC development WAC Development is iterative process (involving producer, WMO and regulatory body (approval)) Non radiological WAC Exchanges on international level of practical approach and good practices for developing WAC would be welcomed Process of waste acceptance for disposal should be described in SC

IAEA ASN – Paris4 Topic 2 – challenges SC development Scenarios and modelling Development of scenarios with consideration of probabilities of events/risk Need was felt to exchange experience/develop guidance on how to consider external events for disposal facilities (Long Term) Address public expectations on scenarios

IAEA ASN – Paris5 Topic 2 – challenges SC development Key radionuclides How many/which ones to consider is waste-specific / f(disposal) Welcomed to exchange on the way these RN are identified – exchange experiance

IAEA ASN – Paris6 Topic 2 – challenges SC development Physical-chemical composition With respect to chemotoxic components & composition relevant to LT-safety (e.g. coloids) New types of waste Evaluate whether within current WAC Additional studies, adapt/update SC Address public expectations on scenarios

IAEA ASN – Paris7 Topic 2 – challenges SC development Treatment of uncertainty Scenarios/parameters/models: more commonly treated Uncertainty related to waste characterisation: not yet so much discussed. Use best available knowledge on waste, perform sensitivity analysis in order to assess importance of uncertainties of waste characteristics – topic for exchange

IAEA ASN – Paris8 Topic 2 – challenges SC development Public involvement Public involvement can go far, but up to which level is still suitable (e.g.: design)? Boundary should be clearly defined Active official communication channels recommended It is found useful to have international exchanges on public involvement in development / operation / closure of a disposal facility, and also with emphasis on dealing with social aspects in Safety Case (site selection, design features, scenario development)

IAEA ASN – Paris9 Topic 2 – challenges SC development Climate change Open end. No concensus on what to consider and for how long

IAEA ASN – Paris10 Topic 3 Licensing process Decision making process & licensing process challanges Found to be complex process, due a.o. to involvement of different regulatory authorities Clear regulatory requirements or pre- licensing dialogue in order to understand expectations is not found to be straightforward in some countries – If high level goal based requirements: need (informal) dialogue (e.g. seismic)

IAEA ASN – Paris11 Topic 3 Licensing process Decision making process & licensing process challanges (ctd) Especially in smaller countries, capacity of regulator (and operator) in reviewing or performing studies is found challanging Use of external expertise / PEER reviews can help, but still need for capacity of regulator/operator to endorse/judge Responsabilities in different steps: see PRISM figure