Shadow Map of the Shaken Metropolitan Area - Worst-Case Scenario at the Beginning of the 21st Century (2011)

Shadow Map of the Shaken Metropolitan Area - Worst-Case Scenario at the Beginning of the 21st Century (2011)

Immediately after the Fukushima Daiichi Nuclear Power Plant was severely damaged by the Great East Japan Earthquake in March 2011, a worst-case scenario was secretly discussed within the Japanese government. This document, prepared by Atomic Energy Commission Chairman Shunsuke Kondo, contained a serious scenario in which reactor cooling would completely fail, the containment vessels of Units 1 through 4 would fail one after another, and large amounts of radioactive materials would continue to be released for a long period of time. The estimates placed the area within a 170-kilometer radius of the Fukushima Daiichi Nuclear Power Plant as a forced relocation zone, with a further 250-kilometer radius available for those who wished to move there. This included almost all of Tokyo and Saitama prefectures, as well as the cities of Chiba and Yokohama.

These predictions were not exaggerations, but were based on the critical situation at the time: hydrogen explosions in Units 1 and 3 between March 12 and 15, suspected damage near the pressure suppression chamber in Unit 2, and even the water level in the spent fuel pool in Unit 4 could not be confirmed. The loss of power due to the tsunami rendered all instruments inoperable, and time passed without anyone being able to determine the state of the reactor core. The wind was blowing to the south, and the possibility of radioactive materials flowing into the Tokyo metropolitan area could not be ruled out, and according to Chernobyl standards based on cesium levels in the soil, a forced evacuation of the 170-kilometer radius was scientifically justified.

Society was also shaken by the turmoil. In Tokyo, drinking water, rice, and batteries ran out, long lines formed at gas stations, and rolling blackouts began to destabilize urban functions. The U.S. government had already advised evacuation from the 80-kilometer zone, and U.S. forces in Japan were operating under their own protection standards. There was a real concern that if the government announced the proposed 250-kilometer evacuation zone, diplomacy, economics, and society would all collapse, and this political decision was the reason why the worst-case scenario was treated as unofficial.

What the document showed was the harsh reality that Japan's nuclear administration was unprepared for a chain of severe accidents. Severe accident countermeasures had become a formality, the safety myth of multiple layers of protection covered the entire system, and events such as the loss of total power supply had been neglected. The facts that came to light after the disaster showed that the administration, operators, and regulatory agencies had failed to systematically anticipate crises. The Government of Japan Commission of Inquiry and the Civil Accident Independent Investigation Commission have pointed out these structural flaws in their repeated reports.

The worst-case scenario that cast a shadow over the entire Tokyo metropolitan area was not merely a hypothetical map, but highlighted the very vulnerabilities that Japanese society was facing at the beginning of the 21st century. How would society coexist with the massive apparatus of technological civilization? What should the nation and its citizens learn and prepare for in the face of these signs?