The Day RCIC Treaded on Unit 2: Three Days of Unquenchable Cooling Fires at the Fukushima Daiichi Nuclear Power Plant (2011)

The Day RCIC Treaded on Unit 2: Three Days of Unquenchable Cooling Fires at the Fukushima Daiichi Nuclear Power Plant (2011)
At the Fukushima Daiichi Nuclear Power Plant, the tsunami of March 11, 2011 caused an instantaneous loss of all power and shut down many cooling facilities. In Unit 2, the reactor core isolation cooling system (RCIC) barely continued to operate under the most extreme conditions. This system, which uses steam power to turn its own pumps, is not normally designed to operate for long periods of time, but it remained functional until the third day after the earthquake, continuing to inject water into the reactor. These three days are regarded as critically important in delaying the progression of core damage.
At the time, the loss of onsite instruments meant that work continued without an accurate grasp of the state of the reactor, and the very survival of RCIC itself became a critical juncture in its fate. If the reactor had been shut down early, it was highly likely that Unit 2 would have suffered rapid core damage and a hydrogen explosion, just like Units 1 and 3. Society as a whole was unable to grasp the circumstances of the accident, and anxiety spread, leading to continued confusion over the disclosure of information by the government and TEPCO. The three days that the RCIC remained in operation are recorded as a symbolic time in the history of the accident.