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EDF has met all the regulatory deadlines and its
commitments.
Nevertheless, ASN has supplemented its demands with
a set of resolutions dated 21st January 2014 aiming to
clarify certaindesignprovisions of thehardened safety core.
ASN’s demands are part of a continuous process to improve
safety and aimtobe able to copewith situations far beyond
thosenormally considered for this type of installation. They
concernmeasures toprevent andmitigate the consequences
of an accident for all the installations on a site, beyond their
initial designconditions. They requirebothadditional fixed
resources andoff-sitemobile resources. In the international
context, these demands stand out through the scope and
scale of themeasures adopted in thewake of theFukushima
Daiichi accident.
Giventhenatureoftherequiredwork,thelicenseemustcarry
out studies for the design, construction and installation of
newequipment, which first require time and then require
a schedule to optimise their implementation on eachNPP.
Insofar as these major works are carried out on nuclear
sites which are in service, it is also necessary to ensure
that their implementation does not degrade the safety of
the power plants.
To take account of both the engineering constraints
involved in these major works and the need to introduce
the post-Fukushima improvements as soon as possible,
their implementation is planned in three phases:
Phase 1 (2012-2015)
Deployment of temporary ormobilemeasures to enhance
protection against the main situations of total loss of the
heat sink or electrical power supplies.
Attheendof2015,EDFhaddeployedtheplannedmeasures.
Phase 2 (2015-2020)
Deployment of definitive design andorganisationalmeans
that are robust to extreme hazards, to deal with the main
scenarios of total loss of the heat sink or electrical power
supplies beyond the baseline safety requirements in force.
The most important measures are:
•
installation of a large-capacity ultimate backup diesel-
generator set, requiring the construction of a dedicated
building to house it;
•
setting up of an ultimate water source;
•
creation of an ultimate water make-up system for each
reactor and each spent fuel pool;
•
reinforcement of the earthquake resistance of the
containment venting filter;
•
construction on each site of a local emergency centre
capable of withstanding extreme external hazards
(functionally independent in an emergency situation).
EDF had already started most of the studies needed to
deploy this equipment. However, discussions are still in
progress concerning the schedule todeploy thesemeasures
on each of the EDF reactors andASNwill issue a position
statement on this subject in 2016.
Phase 3 (as of 2019)
This phase will supplement phase 2, in particular to take
account of other potential accident scenarios. The most
important measures are:
•
removal of the residual power by the steam generators
bymeans of an independent ultimate backup feedwater
system supplied by the ultimate heat sink;
•
addition of a newmakeuppump to the primary system;
•
completion of the fixed connection systems for the SG
backup feedwater supply, the PTR cooling water tank
and the spent fuel pit;
•
installation of an ultimate instrumentation & control
systemand thedefinitive instrumentationof the “hardened
safety core”;
•
installation of a reactor containment ultimate cooling
systemthat does not require opening of the containment
venting-filtration systemin the event of a severe accident;
•
implementation of a solution for flooding the reactor pit
to prevent coriummelt-through of the basemat.
EDF still has to conduct feasibility studies on these latter
two points. Discussions on the schedule for deployment
of the provisions of phase 3 for each of the EDF reactors
are in progress and ASN will issue a position statement
on this subject in 2016.
3.2 Examination of NPP operating
life extensions
The licensee of a nuclear facilitymust conduct a periodic
safety reviewof its facility every ten years (see point 2.9.4).
The reactors of the 900 MWe plant series
The periodic safety review associated
with the third ten-yearly outage inspections
In July 2009, ASN issued a position statement on
the generic aspects of an operating life extension for
the 900 MWe reactors beyond 30 years. ASN has not
identified any generic element that would compromise
EDF’s ability tomanage the safety of the 900 MWe reactors
until the next periodic safety review. ASN considers
that the new baseline safety requirements presented
in the generic safety report for the 900 MWe reactors
and the modifications to the installation envisaged by
EDF are such as to maintain and improve the overall
level of safety of these reactors.
As this generic assessment does not take account of any
individual specific features, ASN gives an opinion on
the ability of each reactor to continue to function, more
specifically based on the results of inspections performed
during the reactor conformity check during the third
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CHAPTER 12:
EDF NUCLEAR POWER PLANTS (NPPs)
ASN report on the state of nuclear safety and radiation protection in France in 2015