Integration of pre-closure and
post-closure safety in the safety
case
Technical meeting GEOSAF Part II
Plenary
26/05/2014
GEOSAF II plenary meeting 26/05/2014
Focus on:
• The stepwise evolution of the
facility / safety case
• The ‘integrated’ safety case
• Post-closure safety
demonstration during pre-closure
GEOSAF II plenary meeting 26/05/2014
IAEA safety requirements
SSR – 5: Disposal of Radioactive Waste
– Scope of safety case of a geological disposal
facility in requirement 13: « shall describe all
safety relevant aspects of the site, the design of
the facility and the managerial control
measures and regulatory controls. The safety
case and supporting safety assessment shall
demonstrate the level of protection of people and
the environment provided and shall provide
assurance to the regulatory body and other
interested parties that safety requirements will be
met. »
– Safety case to address both pre-closure and
post closure safety (§4.15)
– Consider all aspects of operation relevant to
safety (excavation, construction, waste
emplacement, backfilling, sealing, closure)
GEOSAF II plenary meeting 26/05/2013
IAEA safety guide
SSG–23: The Safety Case and Safety
Assessment for the Disposal of
Radioactive Waste
– Focus mostly on long term safety
– Management systems/operational
aspects  identified as important
GEOSAF II plenary meeting 26/05/2013
Stepwise evolution of SC
Requirement 11 from SSR-5 recognises step by step
evolution (development and evaluation)
• “each of these steps shall be supported, as necessary, by
iterative evaluations of the site, of the options for
design, construction, operation and management ,
and of the performance and safety of the of the
disposal facility”.
SSG-23:
• the development of the safety case (thus its level of
detail) is likely to be the outcome of an iterative process
that evolves with the development of the facility.
GEOSAF II plenary meeting 26/05/2014
Steps in process
•
•
•
•
•
Concept development
Site investigation and selection
Design development and construction
Operation and closure
The post closure period
All activities undertaken during the different steps
of pre-closure and closure phases share a common
goal:
To reach a pre-defined target whereby postclosure safety functions have been delivered
GEOSAF II plenary meeting 26/05/2013
The ‘integrated safety case’
• Need for operational (nuclear and industrial) safety and
radiation protection during operational phase: Requires
specific measures  will influence design of facility
(e.g. number of shafts and galeries)
• Goal of opertional phase : to reach predefined target
for post-closure safety (see previous slides)
 necessary to integrate pre-closure and postclosure safety right from early stages in
development
 ‘Integrated’ safety case
 To ensure GDF can be designed, built, operated,
closed in a safe way, taking in account pre-closure
and post-closure safety
GEOSAF II plenary meeting 26/05/2014
Post-closure safety
demonstration during pre-closure
During pre-closure, post-closure safety
demonstration in the safety case will rely on:
• Satisfactory end state reached at moment of
closure (= starting point of post-closure safety
assessment)
But: exact end state will only be known with
significant level of confidence at the time of
closure
GEOSAF II plenary meeting 26/05/2014
Post-closure safety
demonstration during pre-closure
• Assumptione reassessed at each step in the
development of the safety case
• Lessons learned/increased knowledge
 safety case will be regularly updated
But how to deal with the issue of the evolving situation
and lack of knowledge of exact end state?
 some specific concepts are developed to cope
with this and to keep the operational activities
consistent with the requirements on post-closure safety
GEOSAF II plenary meeting 26/05/2014