The long-term management of past severe accidents at nuclear power plants, including Fukushima-Daiichi in Japan, has shown that the existing knowledge base and calculation tools for reactor and spent fuel pool incidents are not sufficiently developed and validated to provide some critical information, a report by the Nuclear Energy Agency says.

The report, Long-Term Management and Actions for a Severe Accident in a Nuclear Power Plant, reviews the Three Mile Island-2, Chernobyl and Fukushima-Daiichi nuclear accidents. It says more knowledge is needed of containment status, and the distribution and properties of radioactive material in the damaged plant. Long-term management would benefit from more predictive tools, the report concludes.