Briefing: Japan’s Nuclear Disaster Continues to Unfold

Published December 11, 2013
By Jacob Grunberger
Publication TTCVR1326
Report available in PDF and Flash formats
On Friday March 11, 2011 at 2:45 pm JST, an earthquake registered as a 9.0 on the Richter Scale occurred near the east coast of Honshu, Japan. The earthquake was comparable in its magnitude to the earthquake that hit Sumatra in 2004, roughly the equivalent of 23,000 Nagasaki bombs being simultaneously detonated. The earthquake and ensuing tsunami destroyed towns and infrastructure, ultimately ending in billions of dollars worth of damage and the confirmed loss of about 16,000 lives.

Located on the northeast coast of Japan, 219 kilometers from Tokyo, the Fukushima Daiichi nuclear power plant run by the Tokyo Electric Power Company (TEPCO) felt the first effects of the event. After the earthquake struck, the proper safety mechanisms tripped, causing all 11 nuclear power reactors to halt the fission process. However, even though the reactors were not running, they were still producing an immense amount of heat. In order to cool the reactors, water had to be circulated over them to prevent overheating and meltdowns. This process also worked to prevent the destruction of the containment apparatuses around the reactors, which guard against radioactive leaks. Despite the earthquake, backup diesel generators were enabling the cooling to occur until the ensuing tsunami struck land. Fukushima Daiichi was designed to withstand tsunami waves of 6 meters, but the waves that hit on March 11 reached 15 meters. Even though most of the reactors successfully went into “cold shutdown,” the pumps in the three oldest reactors failed to work, causing the water in the reactors to boil and the nuclear fuel to heat up, leading the cores to begin melting. The high pressure buildup catalyzed an explosion at all three units, releasing radioactive materials into the air. The nuclear event was rated a Level 7 on the International Nuclear Event Scale due to the large amount of radioactive material leaked into the air during the first couple of days. This was a ranking equal to the Chernobyl nuclear accident, which occurred in the former Soviet Ukraine in 1986. Ultimately, emergency workers stabilized the cores by injecting fresh water and seawater into the reactors, halfway up the core.
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