The Fukushima Accident and Radiological Impact

The Accident

The accident, which took place at the Fukushima Daiichi site on March 11, 2011, was the second accident ever to be reported in the highest category (7) on the INES scale (International Nuclear and Radiological Event Scale) for a civilian nuclear power reactor. The cause was a combination of an earthquake and a subsequent tsunami. The details of the accident are reported elsewhere in this publication. As in Chernobyl, a large-scale local evacuation (tens of kilometers) has taken place, combined with large scale, national control of foodstuffs and drinking water.

The Size of the Radiological Impact Outside Japan

Geographical and meteorological factors and the features of the accident determine its long-range radiological impact. By comparison, the extreme height of the Chernobyl accident's plume accounted for much of its higher long-range effects. In Korea, the maximum air concentration of Cs-137 after the Fukushima accident was around 3 mBq/m3, about 100 times lower than the highest corresponding concentration measured in Sweden [2, 3] after Chernobyl. The EPA's monitoring in the U.S. after Fukushima presented similar values as Korea (around 3 mBq/m3 or

0.1 pCi/m3).

Technical Assessments and Stress Tests in Europe

IAEA Reports

The IAEA issues regular Status Reports to the public on the current status of the Fukushima Daiichi Nuclear Power Plant, which includes information on environmental radiation monitoring, the status of workers, and current conditions on-site at the plant. While information such as IAEA's has been given on a regular basis after the accident, more complete reports have been in preparation for several years, leaving a few years' vacuum or gap in the more detailed public technical discussion for those not directly involved with the assessments.

A comprehensive report from the IAEA will be finalized by year-end 2014. The report contains details from five subgroups covering the areas:

1. A description of the accident as it unfolded, “what happened”;

2. Safety assessment;

3. Emergency preparedness and response and “lessons learned”;

4. Assessment of the radiological consequences to humans and biota; and

5. Post-accident assessment.

The European Union

The European Union (EU) nuclear regulators group (ENSREG) and the European Commission (EC) have carried out stress tests for all reactors in the EU and a number of others (Switzerland and Ukraine, both of which fully participated in the EU stress tests according to the Commission, and Armenia, Turkey, Russia, Taiwan, Japan, South Korea, South Africa, and Brazil). The initiating events studied were earthquakes and flooding.

The initial request was made by the European Council on March 25, 2011 and reports were finalized in 2012 with the lengthy title “Technical summary on the implementation of comprehensive risk and safety assessments of nuclear power plants in the EU, accompanying the document communication from the commission to the council and the European Parliament on the comprehensive risk and safety assessments (“stress tests”) of nuclear power plants in the EU and related activities.”

While both the published EC report and the expected IAEA 2014 report will probably be valuable in boosting discussion on all aspects of nuclear safety, the political impact may not be dependent solely on the technical reports, partly because no drastic conclusions are made or expected and partly because many politicians' opinions have been more or less fixed during the last decades.

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