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Reactor Accidents – An Overview. P. Trampus trampusp@trampus.axelero.net 1st Hungarian - Ukrainian Joint Conference on Safety - Reliability and Risk of Engineering Plants and Components Miskolc tapolca , Hungary, 11 – 12 April 2006. Motto. „Remember, Caesar, thou art mortal”. Content.
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Reactor Accidents –An Overview P. Trampus trampusp@trampus.axelero.net 1st Hungarian-Ukrainian Joint Conference on Safety-Reliability and Risk of Engineering Plants and Components Miskolctapolca, Hungary, 11 – 12 April 2006
Motto „Remember, Caesar, thou art mortal”
Content • Reactor figures • Terminology • The INES • Major reactor accidents • Accident risks
Timeline of First Industrial Scale NPPs around the World
Power Reactor Figures(December 2004) • Reactors in operation: 440 • Reactors under construction: 26 • Reactors shut down: 107 • Operational experience: 11695 years • License renewal issued: > 40 • License renewal in progress: 10 • Letter of intent: 27
Research Reactor Figures(June 2004) • Reactors in operation: 274 • Reactors shut down: 214 • Total number of reactors: 674
Terminology Events: • Accidents • Mortality • Radiation release • Financial consequences (core melt) • Serious / Severe accidents • Incidents • Anomaly • Deviations
The INES Jointly developed by experts of the IAEA and OECD/NEA, in 1989
Nature of Reactor Accidents • Statistics cover • Nuclear power plants • civil • military • Experimental reactors • Research reactors • Reprocessing plants • Fuel manufacturing facilities • Food sterilization plants • Radioactive source accidents • … • Accidents types • Criticality accidents • Non-nuclear accidents (e.g. turbine fire)
Possible Classification of Reactor Accidents • Accidents led to death by exposure to ionizing radiation • Accidents with consequences on the environment and the public • Accidents led to staff exposure above permissible level • Accidents with consequences on plant availability
Criticality Accidents with Death • Los Alamos (USA), 1945 1 dead • Los Alamos (USA), 1946 1 dead (20 Sv) • Vinca (former Yugoslavia), 1958 1 dead • Los Alamos (USA), 1958 1 dead (60 Sv) • Idaho Falls (USA), 1961 3 dead • Woods River Junction (USA), 1964 1 dead • Constituyentes (Argentine), 1983 1 dead • Chernobyl (former SU), 1986 31/50 dead • Tokai-mura (Japan), 1999 2 dead
Accidents with Consequences on the Environment and the Public • Windscale (GB), 1957 • mainly 740 TBq I-131, and others (~1/1000 of Chernobyl) • 126 persons contaminated (max. individual dose 0,16 Sv) • 98 plant workers (max. 0,1 Sv) • external exposure (max. 47 mSv)
Accidents with Staff Exposure • Chalk River (Canada), 1958 10 to 200 mSv • Chinon A1 (France), 1965 500 mSv • Chinon A2 (France), 1979 110 / 340 mSv
Accidents with Plant Unavailability (1) • Heavy Water Reactors • NRX (Canada), 1952 repaired • Lucens (Switzerland), 1969 closed • EL4 (France), 1968 SG replaced • Gas-Cooled Reactors • Chapel Cross (GB), 1967 repaired • Saint-Laurent A1 (France), 1969 repaired • Saint-Laurent A2 (France), 1980 repaired
Accidents with Plant Unavailability (2) • Pressurized Water Reactors • Reactor internals damage (some 20 plants in USA, France, Italy, SU, Germany, China) • SG tube rupture (many plants) • Other incidents • Three Mile Island (partial core melt, extensive inside contamination) - closed • Boiling Water Reactors • Browns Ferry (USA), 1975 – fire • Vandellos 1 (Spain), 1989 – fire closed • Other plants
Accidents with Plant Unavailability (3) • Fast Breeder Reactors • EBR 1 (USA), 1955 • Fermi 1 (USA), 1966 • KNK (Germany), 1971 • BN 350 (former SU), 1973 • Phoenix (France), 1976 • Rapsodie (France), 1982 • Phoenix (France), 1982 each reactor was repaired
Radioactive Source Accidents • False radiotherapy • Costa Rica, 1966 40 dead • Spain, 1990 11 dead • Morocco, 1984 8 dead • Mexico, 1962 4 dead • Lost sources • Brazil, 1987 4 dead (children) • Further 89 dead in various countries
Chernobyl Windscale, Three Mile Island Saint-Laurent A2, Constituyentes Vandellos Accidents in the INES
Historical Review of Accident Forecast • The Brookhaven Report: Theoretical Possibilities and Consequences of Major Accidents in Large Nuclear Power Plants (WASH-740), U.S.AEC, 1957 Qualitative risk assessment • The Rasmussen Report: Reactor Safety Study, an Assessment of Accident Risks in U.S. Commercial Nuclear Power Plants(WASH-1400), U.S.NRC, 1975 Quantitativerisk assessment (first in its kind)
Immediate Mortality Risk due to Severe Accidents
A Scientist’s View „The chance of such an event (i.e. kamikaze-style terrorists aim NPPs) cannot be assessed even by the most astute technicians or engineers: it is a matter of political or sociological judgement. But one would surely have to be a naive optimist to rate it as less than one in a hundred per year.” Martin Rees: Our Final Century, 2003