FRAMEWORK
• I am scientist and researcher in
nuclear and energy issues, speaking
on my own;
• 37 years experience in nuclear
power technology, in start-up and
operation of WWERs, research,
lecturing and regulatory activities;
• Head of Bulgarian Nuclear Safety
Authority, 1997-2001;
• Guest professor in Tokyo Institute
of Technology, 2001-2002.
Today's Nuclear Fleet
• 435 nuclear power reactors (368 GW) in operation
in 30 states, only a few of Generation 3. The total
number and capacity worldwide at plateau during
recent decade;
• 63 reactors under construction, majority are of
Generation 2;
• The average age of operating reactors – 26 years;
• 138 reactors shutdown, average age – 23 years
• Nuclear share in electrical generation about 12 %,
decrease from historical maximum of 17 %;
• 2006 – peak in generated electricity, during
following years – 4 % decrease;
• 134 power reactors in European community, down
from maximum 177 in 1989;
• Asian countries (China, Korea, India, Pakistan)
and Russia are the center of nuclear industry;
Main Risks in NPPs
• Use of fission chain reaction, which could be
uncontrollable under curtain set of conditions;
• High density of heat generation in the reactor core;
• Huge amount of radioactive isotopes in the reactor
core (activity about E+20 Bq at power level),
contaminated equipment and buildings;
• Components under high pressure, high temperature
and dynamic loads;
• Residual radiation/heat generation;
• Generation of spent fuel and radioactive waste;
• Additional;
• Complacency, negligence, self-confidence, lack of
ability to learn from others, underestimation of
threats, lack of questioning attitude.
Nuclear safety of NPP in absolute sense does not
exists! Accidents will occur!
INES SCALE
• INES has seven Levels, with Level 7 being the most severe.
There is also a Level 0, which is considered to be below the scale
and having no safety significance;
• Events classified as INES Level 1 through 3 are referred to as
"incidents". Events classified as INES Level 4 through 7 are
referred to as "accidents".
INES SCALE
ACCIDENTS BEFORE INTRODUCTION
- One accident Level 7 (release equivalent to more than
several tens (50) of thousands of TBq of 131I) – 1986,
Chernobyl Unit 4, USSR;
- One accident Level 6 (release equivalent to a release of
thousands to tens (5-50) of thousands of TBq of 131I – 1957,
Kyshtym, USSR;
- Two accidents Level 5 (release equivalent to hundreds to
thousands of TBq of 131I) – 1957, Windscale, UK and 1979,
Three Mile Island Unit 2, US;
- One known accident classified as Level 4 (the Saint Laurent
des Eaux accident, 1990, France)
INES SCALE
EVENTS AFTER INTRODUCTION
One Level 4 - Tokaimura criticality accident, 1999, Japan.
At least 123 Level 3 incidents worldwide since 1991. Main reasons include
wrong design, complacency, negligence, self-confidence, poor safety culture,
lack of ability to learn from others, underestimation of threats, etc.
- Data falsification in TEPCO reactors, Japan, 1992-2004;
- Reactor pressure vessel head corrosion at Davis-Besse NPP, USA, 1990-2002. About
15x12,5x17,5 cm hole in the main material;
- Ex-core fuel damage in Paks NPP unit 2, Hungary, 2003. 30 fuel assemblies severely
damaged, big radioactive releases to the environment, unit shutdown for 17 months;
- Anticipated Transient Without Scram (ATWS) waiting to happen at Kozloduy NPP unit 5,
Bulgaria, 2005-2006. Neutron absorbers jammed in upper position, 22 of 61 inoperable
even with control rod drive mechanisms;
- Loss of off-site power and failure of 2 from 4 emergency trains at Forsmark NPP unit 1,
Sweden, 2006;
- During recent years concerns expressed regarding the quality of designs, equipment and
services in nuclear industry.
Residual Risks Report
FUKUSHIMA IMPACT 0N EUROPE
•
•
•
•
•
•
•
Germany - permanent closure of 8 reactors and planned
abandonment of nuclear power in the country till 2011;
Switzerland - termination of discussions to construct new NPP
and imposition of dates for final shutdown of the fife reactors;
Italy - abandonment, by public referendum, construction of
proposed new NPP;
Belgium – in October 2011 conformed that in accordance with
the 2003 nuclear phase - out law the three reactors will be
shutdown in 2015 and the rest four – in 2025;
Reconsideration and delay in nuclear programs in the number of
countries;
Implementation of “Stress tests” of European NPPs.
Reduction by 50 % of the previous estimate of IAE for the new
nuclear generating capacity worldwide for 2035;
STRESS TESTS OF EUROPEAN NPPS
•
•
•
•
The stress tests of European NPPs as defined by
European Council should be “a comprehensive and
transparent risk assessment ” of the plants;
European Nuclear Safety Regulators Group (ENSREG)
defined “stress test” as a targeted reassessment to
the extreme natural events;
Stress tests will be accomplished on voluntary basis.
There are countries outside EU with nuclear power
reactors.
STRESS TESTS OF EUROPEAN NPPS
The main and super ordinate target of “stress tests”
would be (only) mitigation of big radioactive releases
to the environment following a severe incident.
Three questions have to be answered:
•
•
•
How to avoid re-criticality of the nuclear material
even the control systems are not available;
What additional devices and procedures are needed to
cool the core and spent fuel pool for long time. How
long it takes for fuel rods to start melting?;
What additional devices and procedures are needed to
keep radioactive materials inside the containment or
to mitigate emissions to the environment.
STRESS TESTS OF EUROPEAN NPPS
•
•
•
•
The report should consists of four main parts:
Up-to-date plant description;
Description of the design basis of the plant and
weather the plant copes with its design requirements;
Assessment of so-called “robustness” beyond the
design basis in case of earthquake and flooding and
total loss of electrical power;
Description of potential improvements.
STRESS TESTS OF EUROPEAN NPPS
LIMITED SCOPE
•
•
•
•
•
•
•
•
•
Only power reactors included;
Only external hazards are considered,
Internal hazards (break of components, pipe leakage,
fires, cooling circuit clogging, electrical surges, etc.)
combination of events, human errors, safety culture,
defense in depth, other aspects are not considered;
No consideration on the quality of equipment and
systems and on the degradation/aging effects;
Prevention of accidents almost not discussed;
Crash of heavy airplane not discussed;
Terrorists activities not discussed;
Civil liability for nuclear damage not discussed;
Stress tests are not a periodical safety review of
STRESS TESTS OF EUROPEAN NPPS
LIMITED TIME
•
•
•
•
Limited time to accomplish the stress tests by
nuclear operators (less than 6 months) - no
new studies and investigations;
The existing studies do not take into account
multiunit plant design, do not consider
circumstances of Fukushima accident, some
are “customer friendly”, some of them (PSA)
were completely wrong;
The time for regulators to prepare evaluation
too short (less than three month);
Limited time for peer review (January 2012 –
STRESS TESTS OF EUROPEAN NPPS
NO CRITERIA
•
•
•
•
No common calculation methods and criteria
how to evaluate the seismic hazard;
Robustness – what is this? No criteria for
acceptance level;
Stress tests mostly relay on “engineering
judgment”;
No requirements about the format of reports,
not possible to compare reports of different
countries.
STRESS TESTS OF EUROPEAN NPPS
LACK OF INDEPENDENCE
•
•
•
•
•
•
No independent safety regulator in European Union;
The stress tests accomplished by the same organizations
(operators, regulators, technical support organizations) and the
same experts that have been responsible for the plant safety in
the past (remember test falsification by TEPCO);
The main players are in visible conflict of interest;
The experience show a number of accidents where nuclear
operators and regulators demonstrated lack of competence and
responsibility;
The experience show the safety requirements differ from
country to country;
The key nuclear organizations failed to acknowledge the real
severity of Fukushima accident.
STRESS TESTS OF EUROPEAN NPPS
LACK OF TRANSPARANCY AND
OPENNESS
•
•
•
•
•
No independent experts and NGOs are involved
in the preparation of reports;
Reports and the main underlying documents are
not open to the public;
No public discussion in the countries;
Limited participation of independent experts in
the review process;
Limited participation of the public in the
discussions at European level.
STRESS TESTS OF NPPS
WHAT WOULD BE A RESULT OF STRESS TEST
TO FUKUSHIMA DAIICHI NPP BEFORE
MARCH 11?
STRESS TESTS CANNOT MAKE
THE PLANTS SAFE
STRESS TESTS OF EUROPEAN NPPS
•
•
•
•
•
•
•
POLITICAL DECISIONS ARE NEEDED BASED ON
SIMPLE TECHNICAL CRITERIA:
To shutdown reactors with significant seismic or other
external hazards;
To shutdown the oldest reactors of Generation 1;
To shutdown reactors without full pressure
containment covering the spent fuel pool;
To stop construction of reactors on sites with
significant external hazards;
To construct only Generation 3 reactors;
Comprehensive safety assessment according to the
newest safety standards to all nuclear facilities with
involvement of independent experts and public;
Increase and unification of civil liability for nuclear
damage.
THANK YOU
FOR YOUR ATTENTION