Nuclear Reactor Hazards

January 21, 2008

By Anthony Frogatt

Nuclear Issues Paper No. 2
By Anthony Frogatt

The complete paper (48 pages, 278 KB, pdf) can be downloaded from here.


The report is based exclusively on Greenpeace International’s report "Nuclear Reactor Hazards, Ongoing Dangers of Operating Nuclear Technology in the 21st Century," published in April 2005. The sections look at the characteristics and inherent flaws of the main reactor designs in operation today; the second part assesses the risks associated with new designs, and discusses the "ageing" of operational reactors; and the third part looks at the terrorist threat to nuclear power.

The main conclusions are:

  • All operational reactors have very serious inherent safety flaws which cannot be eliminated by safety upgrading.
  • A major accident in a light-water reactor, the large majority of the reactors, can lead to radioactive releases equivalent to several times the release at Chernobyl and about 1000 times that released by a fission weapon.
  • New reactor lines are envisaged which are heralded as fundamentally safe. However, apart from having their own specific safety problems, those new reactors would require enormous sums for their development, with uncertain outcome.
  • The average age of the world’s reactors is around twenty-one years and many countries are planning to extend the lifetime of their reactors beyond the original design lifetime. This leads to the degradation of critical components and the increase of severe incidents. The age-related degradation mechanisms are not well understood and difficult to predict.
  • Deregulation (liberalization) of electricity markets has pushed nuclear utilities to decrease safety-related investments and limit staff. Utilities are also upgrading their reactors by increasing reactor pressure, operational temperature, and the burnup of the fuel. This accelerates ageing and decreases safety margins. Nuclear regulators are not always able to fully cope with this new regime.
  • Reactors cannot be sufficiently protected against a terrorist threat. There are several scenario’s, aside from a crash of an airliner into the reactor building, which could lead to a major accident.