Q&A. Nuclear stress tests – Commission
What are nuclear stress tests?
The "stress tests" are a set of comparative
criteria drawn up in the light of the nuclear
accident in Fukushima. These EU wide tests will
be in addition to existing the framework already
applied at national level. Their aim is to
assess whether the safety margins used in the
licensing of nuclear power plants were
sufficient to cover also extreme unexpected
The aim is to learn from what happened in Japan
and help p revent that a similar accident can
happen in Europe. One of the most important
lessons to be drawn is that the extreme
situations such as two natural disasters can hit
at the same time and knock out the electrical
power supply system completely. In Japan, the
power plant withstood the earthquake but the
tsunami interrupted the power supply which is
necessary to cool down fuel elements. If they
are not cooled down, there is a risk of a core
meltdown with leakage of radioactivity and
radiation getting into the soil and the water.
What is being assessed in the stress tests?
It is assessed whether the nuclear power
plant can withstand the effects of the following
1. Natural disasters: earthquakes, flooding,
extreme cold, extreme heat, snow, ice, storms,
tornados, heavy rain and other extreme natural
2. Man-made failures and actions. These
accidents can be: air plane crashes and
explosions close to nuclear power plants,
whether caused by a gas container or an oil
tanker approaching the plant, fire or damaging
effects from terrorist attacks.
What is the state of play of the stress tests?
Comprehensive risk and safety assessments
("stress tests"), based on commonly agreed
criteria, started in all EU Member States that
operate nuclear power plants before 1 June.
By mid August, nuclear plant operators carried
out part of their self-assessment and sent
national regulators their first interim report.
By 15 September, the national regulatory
authorities checked these first self-assessments
and compiled national progress reports. All 14
Member States that operate nuclear power plants
(Belgium, Bulgaria, Czech Republic, Finland,
France, Germany, Hungary, the Netherlands,
Romania, Slovak Republic, Slovenia, Spain,
Sweden and United Kingdom) plus Lithuania, which
is currently decommissioning its nuclear power
producing units, submitted these progress
reports to the Commission by 15 September.
Similar reports were received from Switzerland
and Ukraine, which accepted to take part in the
exercise as neighbouring countries.
When will the EU present the results of the
The national regulator will have to submit
their final report by 31 st December. This will
be followed by peer reviews which will be
completed in April 2012. Safety experts from all
EU Member States, including those who do not
operate nuclear power plants, and Commission
experts in nuclear safety will participate in
peer review teams. National regulators under
review should give the peer review team access
not only to all necessary information but also
to nuclear power plants.
The Commission will present its final report on
the stress tests to the European Council of
28-29 June 2012.
What are Commission's initial impressions based
on the national reports?
Subject to confirmation by the final
national reports, the interim report recognises
that in general nuclear operators follow and
implement the agreed methodology. However, the
format, content and level of detail of the
reports vary substantially and the Commission's
preliminary analysis indicates that the national
regulators have different approaches to safety
and use varying criteria to define safety
improvements. For example, seismic risks are
dealt with very differently and they seem to be
evaluated independently of the actual seismicity
of the regions concerned.
How can the results be compared if the reports
are different from each other?
The Commission wants to enhance the
coherence and comparability of the final
national reports. To this end, it has agreed,
together with the national regulators, a
detailed common structure, which final national
reports will have to follow.
The central element of this structure is the
evaluation of safety margins for earthquakes,
flooding, extreme weather conditions, loss of
electrical power (including back-up and off-site
supply) and loss of cooling capacity. It also
contains a detailed chapter on severe accident
management (measures to cope with major
accidents, such as serious damage to the fuel or
even the core meltdown and loss of containment
capacity, resulting in important radioactive
What about man-made risks, such as terrorist
There is no nuclear safety without security.
Nuclear security aims at preventing intentional
acts that might damage a nuclear facility or
result in the theft or dispersion of nuclear
materials. In the EU, only few of the national
safety regulators have specific responsibility
for the security of nuclear power plants.
Moreover, security competencies in the Member
States are spread among different bodies.
Security issues are an important part of the
overall assessment process. Member States,
assisted by the Commission, are directly in
charge of assessing nuclear security. To that
end, the Council set up the Ad-hoc Group on
Nuclear Security (AHGNS). Its report is annexed
to the Commission interim report.
The final results of the Group's work will be
published in its final report by June 2012.
Switzerland and Ukraine are participating in the
stress tests? What about other EU neighbours?
The Commission has involved in a common
assessment process those EU neighbours that
operate or own nuclear power plants or have
clear plans for the development of nuclear
power. Two of these countries – Switzerland and
Ukraine – participate fully in the EU stress
test process and have provided their progress
reports. The Russian Federation stated that they
had already performed safety re-assessments for
their own nuclear power plants but they are
interested to participate in the EU peer
The Commission aims to further enhance its
cooperation with the International Atomic Energy
Agency. It advocates improvements in the global
legal framework for nuclear safety, especially
the Nuclear Safety Convention, with the aim of
increasing its effectiveness, governance and
Are the results of the reports public?
Yes. All reports, including national reports
and peer reviews, are or will be available at
Are there already conclusions available?
At this stage of the assessment process, any
conclusions on overall stress tests results for
a particular Member State or on plant-specific
results would be premature. Therefore, the
interim report contains only preliminary
suggestions, which will be further elaborated in
the light of the final outcome of the stress
tests. The Commission will outline EU
legislative initiatives in its final report to
the European Council in June 2012.
Does the Commission propose any concrete
In parallel, on the basis of initial
findings, the European Commission is reviewing
the EU nuclear safety legislation and envisaging
ways for improvement.
In particular the Commission is considering:
Minimum technical safety requirements .
Today different Member States apply different
safety margins in nuclear power plants. EU-level
technical criteria in the areas of siting, plant
design, construction and operation could be
created. For instance, the criteria could
establish a minimum distance of the plant from
the sea. These criteria should be a reference
point when licensing or checking the operations
of the plants.
- Licensing and checks . National regulatory
authorities are responsible for issuing licenses
for new nuclear power plants and controlling the
operation of the existing ones. To do this
effectively they need to be completely
independent. Their decisions and the reasoning
behind them should be made available for the
- Cross-border emergency response . A possible
radiological emergency would not stop at
national borders. Therefore cross-border
emergency plans should be put in place. These
plans should foresee sharing and the
availability of healthcare and response
equipment, such as back-up generators in the
event of loss of power in the plant.
- European liability schemes . Different Member
States apply different liability regimes. For
example, some countries require unlimited
liability in terms of compensation to victims
while in others only limited amounts are
available. Victim protection should not depend
on the nationality of the victims, therefore
some minimum requirements should be put in place
at EU level.