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NPPs Risks, World after Fukushima, Stress tests of European NPPs RISK SEMINAR JAPAN January 2012

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NPPs Risks, World after Fukushima, Stress tests of European NPPs RISK SEMINAR JAPAN January 2012 Dr. G. Kastchiev FRAMEWORK I am scientist and researcher in nuclear ... – PowerPoint PPT presentation

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Title: NPPs Risks, World after Fukushima, Stress tests of European NPPs RISK SEMINAR JAPAN January 2012


1
NPPs Risks, World after Fukushima, Stress tests
of European NPPsRISK SEMINAR JAPANJanuary
2012
  • Dr. G. Kastchiev

2
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.

3
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

4
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 E20 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!

5
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".

6
INES SCALEACCIDENTS 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)

7
INES SCALEEVENTS 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.

8
Residual Risks Report
9
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

10
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.

11
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.

12
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.

13
STRESS TESTS OF EUROPEAN NPPSLIMITED 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 NPP

14
STRESS TESTS OF EUROPEAN NPPSLIMITED 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
    April 2012)

15
STRESS TESTS OF EUROPEAN NPPSNO 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.

16
STRESS TESTS OF EUROPEAN NPPSLACK 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.

17
STRESS TESTS OF EUROPEAN NPPSLACK 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.

18
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

19
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.

20
THANK YOU FOR YOUR ATTENTION
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