The document summarizes a workshop on operational safety for geological radioactive waste repositories held in Washington, D.C. in September 2016. It provides background on why operational safety is increasingly important as programs mature. The workshop objectives were to explore how implementers address operational safety, identify effective design alternatives, evaluate regulatory frameworks, and identify topics needing further work. Key challenges discussed included the regulatory environment, system design and controls, operational safety assessment, monitoring, and maintaining a strong safety culture over decades of operations.

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NEA/IAEA Workshop on Operational Safety:
- Summary of Presentations and Discussions -
Wilhelm Bollingerfehr
DBE TECHNOLOGY GmbH
Washington, DC
September 7-9, 2016

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Contents
• Background
• Objectives of the Workshop
• Workshop Format
• Workshop Summary and Future Challenges

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Background
For decades, geological disposal programmes
 focussed on long-term safety,
As programmes have matured:
 aspects related to engineering feasibility and operational safety
have received increasing attention.
 It has become apparent that operating a repository safelty for
many decades is a challenging undertaking,
 as is demonstrating operational safety at a level of detail
adequate to license such operations.

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Common Disposal Concepts
 Deep geological repositories will be
sited, designed, constructed, operated
and closed to isolate RW from the
accessible biosphere;
 Surface operations are as important as
activities in the underground (UG);
infrastructure like shafts and/or ramps
that connects the UG with the surface;
 Deep geological repositories may
remain operational for long period
(up to 100 yrs), may be expanded if
needed;
 ALARA and the defence-in-depth
strategy along with engineered
barriers are often applied to
minimize exposure risks.

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Repository Operations
 Surface facilities: typical processes
include waste acceptance, encapsulation
of conditioned waste; inspection, and
canister preparation / acceptance for
transfer to UG disposal;
 Ready packages are transferred in
shielded transfer cask;
 Emplacement of disposal canisters in UG
boreholes or cells;
 Exposure to workers and the public
during the operational phase is likely
similar as in other nuclear facilities.
Shielded driver cabin – locomotive
(Ondraf/Niras)

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Motivation for a Common Workshop
Both the NEA and the IAEA have long recognised the importance
of operational safety. Projects and work initiatives have been
carried out with different work scopes and objectives to address
various operational safety issues. For instance,
 The NEA IGSC created the Expert Group on Operational Safety
(EGOS) in 2013 to develop the best operating practices and the
optimal design provisions of geological repositories.
 IAEA had launched the GEOSAF Project in 2008 (a forum to
exchange ideas and experience on the development and review
of safety cases for geological disposal facilities).
 Consequentially a common workshop was initiated to share
information and experiences (NEA-OECD-headquarters in
Paris, July 2016)

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Objectives of the Workshop
 Explore how implementers address operational safety in
developing geological repositories for radioactive waste
disposal,
 Identify effective and practical design alternatives used to
achieve operational safety in geological repositories,
 Evaluate the adequacy and comprehensiveness of the existing
regulatory framework guiding implementers in addressing
operational safety in geological repositories and
 Identify areas and topics that require further work.

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Workshop Format
The workshop focuses on three key topics:
1) technical design aspects, e.g. fire risk management, on-site
transportation and emplacement;
2) repository regulatory framework and requirements; and
3) radiological protection issues in DGR,
each one consisting of introducing presentations followed by small
group discussions (guided by specific questions).
 45 Participants from 15 countries attended the Workshop, and
representatives from NEA and IAEA

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Worshop Summary and Future Challenges
1. Regulatory Environment
2. System design and Controls
3. Operational safety assessment and risk management
4. Monitoring and compliance control
5. Safety Culture

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1. Regulatory Environment
 Demonstrating compliance with a wide range of relevant
regulations and coordinating the work of multiple regulatory
bodies, and
 Building and adapting a regulatory system with clear
responsibilities of all involved regulatory bodies. It is also crucial
to maintain regulatory competence;
 Resolving the current lack of international guidance specifically
focussed on the operational safety of geological repositories and
investigating the possibility of integrating harmonising national
regulations;
 Preparing for an emergency situation.

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2. System Design and Controls 1/2
 dealing, e.g. through the development of waste acceptance
criteria, with the often wide range of waste types that can
arise over periods of decades, some of which give rise to
specific safety concerns (e.g. produce gases)
 striking a suitable balance between prevention of incidents
and accidents on the one hand and detection/mitigation on
the other,
 including “resilience” in design, i.e. the ability to respond /
recover effectively in the event of an incident or accident,

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2. System Design and Controls 2/2
 managing possible conflicts in safety requirements (e.g.
between fire safety requirements and provision of a good
working environment during normal operations when
planning ventilation systems) and, more generally, between
construction/operational safety and long-term safety, and
 implementing a system of change management during the
operational period, (must be properly documented for
transparency and also they can give rise to unforeseen
operational safety issues.

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Example: System Design and Controls
Iterative process of design development, with feedback from operational and long-term
safety assessments to design requirements or premises,
(as envisioned by SKB and Posiva)

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3. 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 temperature and duration of fires,
 ensuring waste retrieval operations, if needed, can be
carried out safely in such a way that guarantees
safeguards and security, and
 promoting completeness in evaluating risks or hazards and
the ranges of potential consequences.

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4. Monitoring and Compliance Control 1/2
 clarifying regulatory expectations on monitoring at each
licencing stage,
 demonstrating and maintaining the reliability of monitoring
equipment,
 clarifying the extent to which equipment for monitoring
during the operational phase needs to be removed,
 identifying the role, nature and conditions for post-
operational monitoring,

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4. Monitoring and Compliance Control 2/2
 developing “safety envelopes” that define the ranges of
parameter values that are consistent with safety,
 clarifying what actions to take if parameter values that are
monitored are outside their respective safety envelopes
(including circumstances in which waste packages should
be retrieved), and
 clarifying the roles of underground research laboratories
and “pilot facilities” with regard to monitoring .

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5. Safety Culture
 maintaining the main focus of the organization on safety
over a period of many decades (e.g. continual support from
management, maintaining staff competence, preserving
corporate memory, etc),
 ensuring that schedules and cost concerns do not
compromise safety,
 resolving possible cultural differences between
construction personnel (miners) and operations personnel,
and
 demonstrating an adequate safety culture to stakeholders.

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Acknowlegements
Many Thanks to:
 NEA and IAEA as initiators and organizers of the workshop
 Workshop Programme Committee
 Chairpersons and rapporteurs
 Participants for presentations and discussions
 Paul Smith: Draft summary report

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Thank you
for your attention.