# Canonical recap data for Fukushima Daiichi Nuclear Disaster (2011)
# Source: https://recap.at/2011/fukushima-nuclear-disaster
# Format: YAML 1.2 (UTF-8). Generated at request time.
slug: fukushima-nuclear-disaster
canonicalUrl: "https://recap.at/2011/fukushima-nuclear-disaster"
title: Fukushima Daiichi Nuclear Disaster
aliases:
- Fukushima Daiichi
- 2011 Fukushima nuclear accident
- Tōhoku earthquake and nuclear disaster
subtitle: A magnitude 9.0 earthquake and tsunami triggered meltdowns at three reactors, making it the worst nuclear accident since Chernobyl and reshaping global energy policy.
recapType: global_event
eventStatus: concluded
startDate: 2011-03-11
datePrecision: day
year: 2011
decade: 2010
country:
name: Japan
slug: japan
summaryShort: On 11 March 2011, a major nuclear accident started at the Fukushima Daiichi Nuclear Power Plant in Ōkuma, Fukushima, Japan. The direct cause was the Tōhoku earthquake and tsunami, which resulted in electrical grid failure and damaged nearly all of the power plant's backup energy sources. The subsequent inability to suf
summaryLong: On 11 March 2011, a major nuclear accident started at the Fukushima Daiichi Nuclear Power Plant in Ōkuma, Fukushima, Japan. The direct cause was the Tōhoku earthquake and tsunami, which resulted in electrical grid failure and damaged nearly all of the power plant's backup energy sources. The subsequent inability to sufficiently cool reactors after shutdown compromised containment and resulted in the release of radioactive contaminants into the surrounding environment. It is regarded by the United Nations Scientific Committee on the Effects of Atomic Radiation as the worst nuclear incident since the Chernobyl disaster.
lede: On March 11, 2011, a massive earthquake and tsunami struck Japan's northeast coast, disabling cooling systems at the Fukushima Daiichi Nuclear Power Plant and triggering meltdowns in three reactor cores. It became the worst nuclear accident since Chornobyl, forcing 154,000 people to evacuate and contaminating vast areas with radioactive material.
heroImageUrl: "https://upload.wikimedia.org/wikipedia/commons/thumb/7/7d/Fukushima_I_by_Digital_Globe.jpg/1280px-Fukushima_I_by_Digital_Globe.jpg"
heroImageCredit: Wikipedia · "Fukushima nuclear accident"
importance: 88
sourceConfidence: 75
keyFacts:
- label: Reactor cores affected
  value: 3 (Units 1, 2, and 3)
- label: Evacuation radius
  value: 20 kilometers
- label: People evacuated
  value: 154,000
- label: Evacuated population that never returned
  value: Approximately 40%
- label: Estimated deaths from evacuation stress
  value: ~1,600
- label: Direct earthquake magnitude
  value: 9.0-9.1 (Mw)
- label: Tsunami wave height at plant
  value: ~14 meters
- label: INES rating
  value: Level 7 (maximum, tied with Chornobyl)
- label: Estimated cleanup cost
  value: $200+ billion
timeline:
- date: 2011-03-11
  title: Tōhoku earthquake and tsunami strike
  description: "A magnitude 9.0-9.1 earthquake hits off Japan's northeast coast at 14:46 JST. The subsequent tsunami reaches 14 meters at Fukushima Daiichi, overwhelming seawalls designed for 5.7-meter waves."
- date: 2011-03-11
  title: External power lost, backup generators fail
  description: Tsunami damage destroys diesel generators and electrical equipment. Plant loses ability to cool reactor cores. Emergency battery power lasts eight hours.
- date: 2011-03-12
  title: Reactor 1 hydrogen explosion
  description: "Pressure builds in Reactor 1 containment. Operators vent radioactive steam, hydrogen accumulates in the building, and an explosion destroys the upper structure at 15:36 JST."
- date: 2011-03-13
  title: Reactor 3 hydrogen explosion
  description: "Reactor 3 containment experiences similar pressure buildup and vents radioactive steam. A hydrogen explosion damages the building at 11:01 JST."
- date: 2011-03-14
  title: Reactor 2 containment failure
  description: "Reactor 2 suppression pool loses integrity. Pressure vessel breached. Hydrogen explosion damages the reactor building at 06:20 JST on March 15."
- date: 2011-03-15
  title: 20-kilometer evacuation zone declared
  description: Japanese government orders all residents within 20 kilometers of Fukushima Daiichi to evacuate. Approximately 154,000 people begin leaving the area.
- date: 2011-04-12
  title: INES level 7 classification assigned
  description: Japan Nuclear and Industrial Safety Agency rates the accident Level 7 on the International Nuclear Event Scale, equaling Chornobyl. Initial rating of Level 5 is upgraded after revised damage assessments.
- date: 2011-12-16
  title: Cold shutdown declared
  description: Japanese Prime Minister Naoto Kan announces that all three reactors have reached a 'cold shutdown' state where fuel temperatures stabilize below 100°C.
- date: 2015-09-19
  title: Reactor restart approved
  description: Japan's Nuclear Regulation Authority approves restart of Reactor 1 at Sendai Nuclear Power Station, marking symbolic end to post-Fukushima moratorium, though Fukushima Daiichi remains offline.
- date: 2021-04-13
  title: Treated water release plan announced
  description: Japanese government approves plan to release over 1 million tons of treated cooling water into the Pacific Ocean beginning 2023, sparking regional criticism.
sources:
- url: "https://en.wikipedia.org/wiki/Fukushima_nuclear_accident"
  title: Fukushima Daiichi Nuclear Disaster
  provider: Wikipedia
related: []
impactStatement: The disaster killed roughly 1,600 people in evacuation-related deaths, displaced over 150,000 residents permanently, and fundamentally altered Japan's energy policy—leading to a nationwide nuclear shutdown and pivot toward renewables. It demonstrated that even advanced industrial nations with rigorous safety protocols remain vulnerable to cascading infrastructure failures when natural disasters exceed design parameters.
categories:
- disaster
metaDescription: March 2011 nuclear meltdown at Fukushima Daiichi triggered by earthquake and tsunami. Japan's worst nuclear accident.
wikidataQid: Q171178
archiveSnapshots:
- url: "https://web.archive.org/web/20130725171106/http://en.wikipedia.org/wiki/Fukushima_nuclear_accident"
  capturedAt: 2013-07-25
  label: Fukushima Daiichi Nuclear Disaster
  originalUrl: "https://en.wikipedia.org/wiki/Fukushima_nuclear_accident"
taxonomy:
domain: environmental
eventTypes:
- natural_disaster
canonicalClasses:
- collapse
impactRadius: regional
velocity: sudden
predictability: black_swan
intentionality: natural
domainCoupling: multi_domain
