GRS published its first report on the reactor accident at Fukushima at the beginning of December. The report with the title „The accident at Fukushima – Interim report on the event sequences in the nuclear power plants following the earthquake of 11 March 2011“ (GRS-293)  is the first result of a project that GRS is working on by order of the Federal German Environment Ministry (BMU). The focus of the project is on a reconstruction of the course of the accident, an evaluation of the events and the derivation of first insights for the benefit of German nuclear power plants.

What is the report about?
This new report summarises the most relevant findings until August of this year. The aim is to allow as integral a view as possible of the accident sequence – from the earthquake up until the emergency and support measures.

For this report, GRS has carried out a highly detailed evaluation of the data  that have been provided so far by the Japanese regulatory authority Nuclear and Industrial Safety Agency (NISA) and the utility operating the nuclear power plants at Fukushima, Tokyo Electric Power Company (TEPCO). For example, GRS has evaluated data from recorders that can give clues to which systems were unavailable at what points in time. On the basis of these data it is possible to draw a broad picture of the accidents. As the data are incomplete and further analyses have yet to be performed, it is so far not possible to make any reliable statements on the extent of the core damage or even on the state of the reactor pressure vessels.

Besides the latest plans on the part of the licensee and the Japanese government to relieve the situation, the report also contains the results of the evaluations carried out by NISA and the International Atomic Energy Agency (IAEA).

Conclusions for German plants
One general objective of the studies relating to Fukushima is to derive insights for German plants. Although one cannot apply the accident one-to-one to German plants – as these are designed differently, a tsunami is unlikely, and the emergency-power-generating installations are in part physically separated from each other and protected against external hazards – it still has to be checked which consequences two successive extreme external impacts (like the earthquake and the tsunami in Japan) would have for German nuclear power plants.

In its report, GRS recommends that the German nuclear power plants should be assessed plant-specifically – each plant for itself – against the background of the Japanese reactor disaster. Concrete recommendations are to be made by GRS in the form of a so-called Information Notice.

Crisis centre, crisis team and Fukushima information portal of GRS
Between 11 March until the beginning of August 2011, the GRS crisis team collected and evaluated all the information available on the reactor accident at Fukushima for the BMU. During this period, more than 200 situation reports were prepared for the BMU.
To inform the general public and the media, GRS compiled these BMU situation reports as well as further, explanatory information in the Fukushima information portal. At present, GRS is continuing to look into the events at Fukushima within the framework of several research projects.

Want to know more?
Website of the Japanese regulatory authority NISA
Website of the Japanese utility TEPCO