Reaktorunfall in Fukushima
One Year after Fukushima
The disaster of Fukushima is one year ago, but the consequences are far from overcome. Immediately after the nuclear accident became known on 11 March 2011, the KIT established working groups for the Helmholtz Association, which continue to edit scientific insights for general publication even today.
In the first three months, the approximately 30 involved researchers worked in part around the clock. In cooperation with the Gesellschaft für Anlagen- und Reaktorsicherheit (GRS - Society for Plant and Reactor Safety) and experts from the USA and Japan, the scientists collected all available data, on the basis of which they then attempted to assess the respective current status and forecast the further development. "Our calculations, for example, regarding the contamination of the ground with caesium, proved to be correct without exception", explains Wolfgang Raskob, who with his team at the KIT compiled daily forecasts.
Great Demand for Verified Information
The working groups published their results on the KIT's website under www.helmholtz.de/kit-fukushima (in German). In the period between March 2011 and January 2012, these pages registered about 54,000 access hits. "The graphs regarding the calculations of the spreading were accessed even in Japan as independent information", reports Dr Joachim Knebel, Chief Science Officer at the KIT and Programme Spokesperson Nuclear Safety Research for the Helmholtz Association. At the same time more than 270 articles in online media, more than 150 articles in printed media, over 50 television broadcasts and more than 80 radio broadcasts reported on the work of the Helmholtz researchers at the KIT in the wake of Fukushima.
Current Situation in Fukushima
At the end of the past year, a delegation from the Japan Atomic Energy Agency visited the KIT to gather information regarding reactor safety research on site and enter into an agreement on increased cooperation. In the region around the nuclear power plant site Fukushima, the Japanese currently attempt to prepare the decontamination of several hundreds square kilometres of ground. "By excavating an approximately five-centimetre thick layer of top soil, the radiactive contamination is to be reduced to below the threshold value of five millisievert", explains Wolfgang Raskob. However, as yet there is no long-term solution in sight for the storage of the excavated soil. At the plant itself, protective covers consisting of steel framework and polyester sheets are currently erected to create a gas tight enclosure around the reactors. Steel sheet pile wall rammed into the ground about 23 metres deep are to prevent the leakage of radioactively contaminated water from the reactors into the ocean or the ground water. "By now, there is a fully operational cooling circuits in place again", says Raskob. Debris and scrap metal are to be removed from the plant bit by bit in order to finally dismantle it and/or encase the areas with the highest degree of radioactivity in a sarcophagus.
From today's point of view, nuclear technology experts from the IAEA, who met at the HZDR in March 2012, evaluate the situation as follows: In the high-technology country Japan nuclear power plants were not sufficiently fit to survive major natural catastrophes without presenting a danger to the environment and population. Modern passive safety systems are very likely to have reduced the discharge of radioactivity, yet were not featured in the plants at Fukushima. By contrast, the German nuclear power plants continue to be amongst the safest worldwide and the German know-how as regards reactor safety enjoys international high esteem.
To the Helmholtz Fukushima website (in German)
After the events in Japan, many people want to know more about the future consequences of the hazardous incidents.
Experts from the Helmholtz Zentrum München have compiled some answers: www.helmholtz.de/faq-zu-fukushima (in German)