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Science and Technology of Nuclear Installations
Volume 2012 (2012), Article ID 384987, 6 pages
Research Article

Empirical Risk Analysis of Severe Reactor Accidents in Nuclear Power Plants after Fukushima

Softwareentwicklung & Umwelt-Consulting, Kienestraße 1a, 80933 München, Germany

Received 30 March 2012; Revised 1 August 2012; Accepted 3 August 2012

Academic Editor: Keith E. Holbert

Copyright © 2012 Jan Christian Kaiser. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Many countries are reexamining the risks connected with nuclear power generation after the Fukushima accidents. To provide updated information for the corresponding discussion a simple empirical approach is applied for risk quantification of severe reactor accidents with International Nuclear and Radiological Event Scale (INES) level 5 . The analysis is based on worldwide data of commercial nuclear facilities. An empirical hazard of 21 (95% confidence intervals (CI) 4; 62) severe accidents among the world’s reactors in 100,000 years of operation has been estimated. This result is compatible with the frequency estimate of a probabilistic safety assessment for a typical pressurised power reactor in Germany. It is used in scenario calculations concerning the development in numbers of reactors in the next twenty years. For the base scenario with constant reactor numbers the time to the next accident among the world's 441 reactors, which were connected to the grid in 2010, is estimated to 11 (95% CI 3.7; 52) years. In two other scenarios a moderate increase or decrease in reactor numbers have negligible influence on the results. The time to the next accident can be extended well above the lifetime of reactors by retiring a sizeable number of less secure ones and by safety improvements for the rest.