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Safety of WWER Reactors

Safety of WWER Reactors. Wolfgang Kromp Institute of Risk Research University of Vienna. Budapest, 23.04.2007. Tschernobyl September 1999. Nuclear revisited PLUS TMI-Upgradings PSA SAMGs MINUS Timeliness Liberalized market Aging Lack of nuclear grade spare parts Lack of personnel

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Safety of WWER Reactors

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  1. Safety of WWER Reactors Wolfgang Kromp Institute of Risk ResearchUniversity of Vienna Budapest, 23.04.2007

  2. Tschernobyl September 1999

  3. Nuclear revisited PLUS • TMI-Upgradings • PSA • SAMGs MINUS • Timeliness • Liberalized market • Aging • Lack of nuclear grade spare parts • Lack of personnel • Human factor & societal instability

  4. Nuclear revisited Further Questions • Life Extension • Power Uprating • Fissile Uranium

  5. WWER Electricity Steam Generator Turbine Generator Heat Sink Energy Source

  6. Short visitors’ Loviisa plant description  Mainossanoma OY / Vientipaino OY 1982 Imatran Voima OY P.O.Box 138, 00101 Helsinki 10, Finland

  7. Nuclear Engineering International

  8. Reactor Pressure Vessel (RPV) 55° Cold water injection through ECCS RPV-wall and welds embrittle due to neutron irradiation Reactor with fuel 300° hot RPV wall

  9. After 5 years of service already 50% of neutron induced material damage Counter measures: early shielding & annealing

  10. Pre-Service Thermal-Shock Analysis Mochovce (IAEO 1994 old , Posar 1997 new limit):Updated Codes resulted in lower limit, Even newly calculated embrittlement graph could not entirely solve the problem

  11. F. Horvath 2002complemented

  12. „Events“ since 2000 • Brunsbüttel (00) – tube line leakage • Japan (02) – data falsification • Davis-Besse (90-02) – vessel lid corrosion • Koslodui (03) - LOCA • Paks (03) – fuel damage • Repro plant Sellafield (04-05) – Leekage • Kosloduy (06) – control rod jamming • Forsmark (06) – loss of off-site power etc. • …

  13. J. Schunk et al: Fuel Assemblies Chemical Cleaning, Framatome ANP GmbH, Germany, (2001) Fig. 3: Cleaning tank temporarily installed in pool no. 1

  14. Warnings • IAEO-Generaldirektor El Baradei, New Orleans , Nov. 03: • „We cannot afford another accident“ • WANO Chair Hajimu Maeda, Okt. 03: • “a terrible disease that originates within the organization” • “a major accident” … “destroy the whole organization“

  15. Extension of Operational Life-Time: WWER-Related Aspects • Main focus on ageing at VVER–plants: • Reactor vessel [1] • Ageing of components • Confinement tightness • Internals, Piping • Concrete • RPV Embrittlement • VVER 440/ 213 End of Life depends on weld Radiation Embrittlement • Radiation Embrittlement depends on P and Cu contents • [1] Control of permanent set structures state at definition of nuclear power plants lifetime Ya. I. Shtrombakh

  16. Extension of Operational Life-Time: Paks-Related Aspects • Systematic preparatory work for long-term operation of Paks NPP WWER-440/213 units had started in 2000 and is on going [2] • Ageing Management (AM) measures concentrated for Paks NPP on: • RPV embrittlement • Leaking of confinement due to liner degradation, • Seismic resistance of bubbler condenser ) • Corrosion of SG heat exchange tubes (magnetite problem) • etc. • [2] KEY ELEMENTS OF LONG TE M OPE ATION OF WWE -440/213 UNITS AT PAKS NPP T. Katona, S Rátkai Nuclear Power Plant Pak, Hungary

  17. Extension of Operational Life-Time: Paks-Related Aspects • Additional Questions: • International programms & experiences from RPV embrittlement studies e.g. Rovno 1 and 2, Kola NPP sufficietly considered? • Different studies are focused on the RPV base materials and weldings: The condition of metal of the RPV is known as essential for VVER-440 life time [3] • [3] THE EXPERIENCE OF ERVICE LIFE PROLONGATION OF NPP UNIT OF THE FIRST GENERATION, • M. Kakirov, V. Potapov, A. Kann, A. Dementev, V. Levchuk, E. akhus, S. C ubarov, V. Ilyn, E. Mamaeva, A. Mazepa, Centre of Materials Researches and Lifetime Management, Moscow, Russia, Rostechnadzor, Novovoronezh, Russia Concern “Rosenergoatom”, CNIITMASH, Moscow, Russia

  18. Timeliness Limits: • Construction capacity • Availabilty of financial resources • Availability of trained personnel

  19. Lead Time

  20. Uranium production and demand Far more Uranium used than produced! Energy Watch Group 2006

  21. Resources • WEC 2000: 62.000 t/a -> 2015 80.000t/a • 4Mio t U235 reasonably assured + estimated additional -> 41a • 10Mio t U235 highly speculative -> 95a

  22. Present & Future Plants • Generation 2 • Generation 3 u. 3+ • Generation 4 Up to Generation 3+ based on fissile U235 Generation 4 mainly based on dangerous Plutonium or Uranium 233 U238 -> Pu239 or Th232 -> U233

  23. Generation 4 • No severe accident • No long lived waste • No matter for proliferation • Cheap  Ordinary fast breeder!  „Pu economy“

  24. Generation 4 • “We have not found and, based on current knowledge, do not believe it is realistic to expect that there are new reactor and fuel cycle technologies that simultaneously overcome the problems of cost, safety, waste, and proliferation” MIT (2003), op. cit., p. 76.

  25. NPP – attractive target • Radioactivity & energy inventory • Key components of electricity networks • Structures visible at large distance

  26. Example of insuccessful terror defence at RBMK Smolensk • Simulated terror attack early eighties • 14 days pre-warning • Security guards prepared • Safety barriers overcome by intrudor • Alarm went on • Intrudor disappeared among personnel • Intrudor communicated with personnel of main circulation pump control room

  27. Radiant Inheritance • Plutonium 239, Technetium 99 HLT 24.000 and 211.000 ys • 9 kg per t spent fuel • Neptunium 237, Cerium 93, Cesium 135, Palladium 107, Iodine 129 HLT 1,5 to 15 million ys • 3,5 kg per t spent fuel • Globally 436 NPPs 10.500 t heavy metal / a 265 000 t spent fuel up to date> 3 300 t long time radio nuclids up to date

  28. Interim storage – anthropogenic threat • Attacke on spentfuel pit  Circonia fire • Could be „well beyond Chernobyl“(Sensintaffar 2005) „Main stream“ deep geological structures?

  29. Geological Deep Repository • Search – AkEnd (Germany) • 1 Mio Years • 300 to 1200m deep • Preferably one site • Sooner or later closed and unaccessible Detlev Ipsen (AkEnd): global societal & political mega experiment

  30. Summary • Remarkable Efforts to be Acknowledged • Old and New Constraints • Persistent „Near Misses“ • Threat of Severe Accident • Unresolved Waste Issue • Daughtful Future Developments • To Small & Late for Climate Change and Fossiles‘ Shortage

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