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Reactor Accidents –Reactor Accidents –An OverviewAn Overview

P. Trampustrampusp@trampus.axelero.net

1st Hungarian-Ukrainian Joint Conference on

Safety-Reliability and Risk of Engineering Plants and Components

Miskolctapolca, Hungary, 11 – 12 April 2006

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MottoMotto

„Remember, Caesar, thou art mortal”

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ContentContent

• Reactor figures• Terminology• The INES• Major reactor accidents• Accident risks

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Timeline of FirstTimeline of FirstIndustrial ScaleIndustrial ScaleNPPs around theNPPs around the

WorldWorld

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Power Reactor FiguresPower Reactor Figures(December 2004)(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

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Research Reactor FiguresResearch Reactor Figures(June 2004)(June 2004)

• Reactors in operation: 274

• Reactors shut down:214

• Total number of reactors:674

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TerminologyTerminology

Events:• Accidents

– Mortality– Radiation release– Financial consequences (core melt)– Serious / Severe accidents

• Incidents• Anomaly• Deviations

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Concept of the International Concept of the International Nuclear Event Scale (INES)Nuclear Event Scale (INES)

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The INESThe INES

Jointly developed byexperts of the IAEAand OECD/NEA,in 1989

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Nature of Reactor Accidents 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)

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Possible Classification of Reactor Possible Classification of Reactor Accidents 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

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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

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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)

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Accidents with Staff Exposure

• Chalk River (Canada), 195810 to 200 mSv

• Chinon A1 (France), 1965500 mSv

• Chinon A2 (France), 1979110 / 340 mSv

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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

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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

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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

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Radioactive Source AccidentsRadioactive 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

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Chernobyl

Windscale,Three Mile Island

Saint-Laurent A2,Constituyentes

Vandellos

Accidents in theAccidents in theINESINES

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Historical Review of Accident Historical Review of Accident ForecastForecast

• 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, 1975Quantitative risk assessment (first in its kind)

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Immediate Mortality Immediate Mortality Risk due to Severe Risk due to Severe AccidentsAccidents

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A Scientist’s ViewA 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