The NEA and IAEA held a joint workshop in Paris in July 2016 to evaluate operational safety at geological repositories for radioactive waste disposal. The workshop explored how implementers address operational safety, identified effective design alternatives, evaluated regulatory frameworks, and identified topics needing further work. Implementers and regulators from a range of programs discussed their approaches to operational safety. The workshop revealed challenges in regulatory compliance, system design conflicts, operational safety assessment, and monitoring reliability.

1. NEA/IAEA workshop on operational safety
Wilhelm Bollingerfehr
7th US/German Workshop on
Salt Repository Research, Design, and Operation
Washington, DC
September 7-9, 2016
ABSTRACT
The NEA and IAEA held a joint Workshop on Operational Safety of Geological Repositories to
evaluate the state of the art in operational safety at the OECD conference centre in Paris in July
2016. The purposes of the workshop were to (i) explore how implementers address operational
safety in developing geological repositories for radioactive waste disposal, (ii), identify effective
and practical design alternatives used to achieve operational safety in geological repositories,
(iii), evaluate the adequacy and comprehensiveness of the existing regulatory framework guiding
implementers in addressing operational safety in geological repositories and (iv), identify areas
and topics that require further work. The 3-day-workshop comprised presentations in the
morning, followed by small group discussions in the afternoon with concluding summaries
afterwards. Implementers and regulators gave insights on their approaches to dealing with
operational safety from a range of programmes. The programmes included those at an early stage
of planning, where operational considerations are rather theoretical, as well as more advanced
programmes, where operational safety is an immediate and pressing concern. Practical
experience on how to deal with operational hazards is now available as well. The workshop
revealed important challenges and questions in a number of areas. Examples are:
• Regulatory environment: demonstrating compliance with a wide range of relevant
regulations, coordinating the work of multiple regulatory bodies, and resolving the
current lack of international guidance specifically focused on the operational safety of
geological repositories
• System design and controls: dealing with possible conflicts in requirements, (e.g.
between fire safety requirements and provision of a good work environment during
normal operations)
• Operational safety assessment and risk management: investigating the possibility to
develop standardised high-level approaches, (e.g. to fire risk management), better
justifying certain key model assumptions (e.g. regarding the temperatures and durations
of fires)
• Monitoring and compliance control: clarifying regulatory expectations regarding
monitoring at each licencing stage, and demonstrating and maintaining the reliability of
monitoring equipment,