Particles of Shadow Carried by the Sea Breeze - Memories of the South Wind that Wrapped Around the Fukushima Daini Nuclear Power Plant (2011)

Particles of Shadow Carried by the Sea Breeze - Memories of the South Wind that Wrapped Around the Fukushima Daini Nuclear Power Plant (2011)
In March 2011, as the accident at the Fukushima Daiichi Nuclear Power Plant was progressing, an increase in radiation levels was also observed at the Fukushima Daini Nuclear Power Plant, located about 12 km to the south. The background to this was the possibility that the operation of the SR valve in the No. 2 reactor of the No. 1 plant had caused high-pressure steam to be released outside, and that radioactive materials contained in the steam were carried toward the No. 2 plant by the southerly winds that were blowing at the time. The coastal area of Fukushima has a strip of land between the sea and mountains, where wind tends to concentrate and flow, creating conditions for radioactive materials to be carried in a specific direction. In the days following the earthquake, data from the Japan Meteorological Agency also indicates that southerly winds were predominant, moving from the first to the second direction. This phenomenon clearly demonstrated the reality that distance
does not guarantee safety in a nuclear accident. A gap of only 12 kilometers could easily be crossed if the wind direction changed, indicating the possibility that the No. 2 nuclear power plant could enter the zone of influence of the accident at the No. 1 plant.

Fortunately, the second plant escaped serious damage, but if serious trouble had occurred at the same time, the entire Hamadori area could have been in jeopardy. Furthermore, the southerly winds made evacuation decisions and monitoring around the Daiichi Nuclear Power Plant difficult, and also affected the variability of radiation levels in different areas. Later surveys also confirmed the southward movement of radioactive materials in the direction of Iwaki City, indicating that weather and topography had a significant impact on the distribution of contamination. The slightly elevated values observed at the No. 2 Nuclear Power Plant are an important clue to deciphering how the accident spread, and illustrate the harsh reality that the natural environment determines the aspect of a disaster.