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| Fig. 1: Damaged Reactors 1-4 (right to left) at the Fukushima Daiichi Nuclear Power Plant. (Source: Wikimedia Commons) |
On March 11th, 2011, a magnitude 9.0 earthquake struck the coast off of the Tohoku peninsula in Northern Japan, triggering one of the world's largest nuclear disasters at the Fukushima Daiichi Nuclear Power Plant. In the ensuing tsunami, waves measuring over 13 m in height crashed over the 5.2-m tidal embankments that had been constructed to protect the power plant, leading to extensive flooding of emergency generators and complete loss of electricity. The failure of cooling systems on site resulted in devastating hydrogen explosions in three of the four damaged reactors and uncontrolled release of radioactive chemicals into the surrounding environment. As with the Chernobyl Nuclear Disaster in 1986, the Fukushima Daiichi Nuclear Disaster was classified by the International Atomic Energy Agency (IAEA) as a Level 7 nuclear disaster. [1,2]
Following the accident, anti-nuclear sentiment predictably dominated public opinions domestically and internationally, as citizens worried about the radioactive contamination of food, drinking water, and local farming soil. Governments were forced to reevaluate nuclear energy policies in the face of this public concern. This report will briefly address the aftermath of the Fukushima Daiichi disaster in Japan, looking at the environmental and social damages of the disaster, resultant changes in the Japanese energy policy and economy, and the steps that the country has taken towards recovering its once-dominant nuclear energy.
Relatively volatile fission products were released by the reactor into the atmosphere, with major isotopes being I-131 (half-life of 8 days) and Cs-137 (half-life of 30 years), and were mainly discharged via atmospheric dispersion from the hydrogen explosions or groundwater leakage due to earthquake and tsunami damage to containment facilities. In the one month post-disaster, around 150 × 1015 Bq of I-131 and 13 × 1015 Bq of Cs-137 were estimated to have been released into the atmosphere. The Japanese Ministry of Education, Culture, Sports, Science, and Technology (MEXT) began monitoring the seawater for radioactivity near the facility in March of 2011, observing a concentration of 77 Bq of I-131 and 24 Bq of Cs-137 were measured per liter of ocean water. [3] Wastewater leakages from the plant have continued since the disaster in March 2011 through late 2015, with Tokyo Electric Power Company (TEPCO), the party in charge of operations at Fukushima Daiichi, even deliberately releasing low-level contaminated waste water into the Pacific Ocean to make space for more radioactive water in the limited containment pools. [4]
In a 2013 study, fish (Hexagrammos otakii) near the damaged facility were reported to show radioactive Cs-134 and Cs-137 levels as high as 740 kilobecquerels per kilogram, well over the pre-disaster levels of 0.03-0.15 becquerels per kilogram. The study also noted that 9 other species of fish likewise showed Cs-134 and Cs-137 levels over 100 kilobequerels per kilogram. [5]
While no deaths were attributed to the release of radioactive materials in the days following the reactor meltdown, around 78,000 people were evacuated from the towns within a 30-km radius from the Fukushima Daiichi Power Plant, with an additional 10,000 people farther to northwest also evacuated due to wind-carried radioactive material. [1] In a study by the Fukushima Medical University, individuals in Fukushima prefecture were estimated to have received a lifetime dose equivalent of around 10 mSv of radiation during the evacuation period (four months post-disaster), with the highest recorded dose being 23 mSv, levels considered by experts to be far below the harmful threshold (100 mSv is generally accepted as the threshold dosage for increased cancer risk). [6] Some power plant workers at the site of the disaster, however, received much higher radiation dosages, with 146 TEPCO employees and 21 contractors received radiation dosages over the 100 mSv limit, 6 receiving over 250 mSv, and 2 operators receiving over 600 mSv. Even so, expert believe that there is unlikely to be a statistically-significant rise in thyroid cancer or leukaemia in these workers. [7]
Even more so than radiation-related physical health effects, deterioration of mental health in Fukushima residents presents a much more prominent social problem. For the 88,000 citizens displaced by radiation exposure, many were forced to exchange their homes and their livelihood for a temporary shack and lifetime anxiety over long-term radiation side effects. [6] Many residents in the surrounding area had been workers at the Fukushima Daiichi Power Plant, and found themselves without a job after the nuclear disaster. Those who depended on farming and fishing lost their businesses due to public fear of consuming radiation-tainted food. Despair in the face of these losses and a general unwillingness to accept help from the government have driven residents to anger, depression, and even suicide. [8,9]
For now, evacuees remain hopeful that they can return home. On September 4th, 2015, over four years after the disaster, the government finally lifted the evacuation order for Naraha, a small town 10 miles from the disaster zone, after radiation levels were shown to have fallen to acceptable limits. Even so, return to the town has been slow, as residents continue to express concern about radiation levels, lack of medical facility, and limited access to daily necessities. [10,11]
Prior to Fukushima, nuclear energy made up 30% of the country's energy sector, with original plans to expand to 50% by 2030. In the aftermath of the Fukushima disaster, however, Japan's energy policy shifted towards an anti-nuclear stance, with then- Prime Minister, Naoto Kan, stating in a July 2011 news conference, "We should reduce our dependence in a planned and gradual way, and in the future we should aim to get by with no nuclear energy." [12] Post-Fukushima evaluation of nuclear energy safety standards had revealed power plant security to be antiquated and inadequate. By May 2012, Japan had shut down all fifty remaining reactors in the country, with the intention to establish strong safety measures before restarting its nuclear program. It is interesting to note, however, that despite shutdown of all nuclear reactors, Japan continued its nuclear fuel cycle program, generating energy from uranium in nuclear breeder reactors. [13] Due to political shifts through the years following the disaster and the political nature of the nuclear commitments, there has yet to be a definite long-term nuclear policy established by the government.
As of January 2016, three reactors total have been restarted in the Sendai and Kyoto Nuclear Power Plants, with another planned in February, in hopes of off-setting the costs accrued by the import of fossil fuels following reactor shutdowns. In an April 2015 proposal, the Japanese government stated its plan of establishing nuclear energy as 20-22% of its energy sector by 2030. [14,15]
Due to the severity of the accident at the Fukushima Daiichi Nuclear Power Plant, the recovery of nuclear energy in Japan has been met with heavy disapproval and doubt from the Japanese public. Ironically, the accident fortunately forced the Japanese government to reexamine all nuclear power plants in the country, during which widespread observation of insufficient maintenance and poor safety regulations in the power plants led to complete retirement and reevaluation of Japan's entire nuclear fleet. As Japan begins its slow return to nuclear power with the start of hopeful model nuclear power plants in Sendai and Kyoto in 2015, it is evident that the aftermath of Fukushima has taught the Japanese government and all countries interested in nuclear power to adhere to the highest safety standards in the face of nuclear energy.
© Evelyn Chang. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] K. Kurokawa et al., "The Offical Report of the Fukushima Nuclear Accident Independent Investigation Commission: Executive Summary," National Diet of Japan, 2012.
[2] T. Ohnishi, "The Disaster at Japan's Fukushima-Daiichi Nuclear Power Plant after the March 11, 2011 Earthquake and Tsunami, and the Resulting Spread of Radioisotope Contamination", Radiat. Res. 177, 1 (2012).
[3] N. Yoshida and J. Kanda, "Tracking the Fukushima Radionuclides," Science 336, 1115 (2012).
[4] P. J. Kiger, "Fukushima's Radioactive Water Leak: What You Should Know," National Geographic, 9 Aug 2013.
[5] M. P. Johansen et al., "Radiological Dose Rates to Marine Fish from the Fukushima Daiichi Accident: The First Three Years Across the North Pacific," Environ. Sci. Technol. 49, 1277 (2015).
[6] G. Brumfiel and I. Fuyuno, "Japan's Nuclear Crisis: Fukushima's Legacy of Fear," Nature 483, 138 (2012).
[7] G. Brumfiel, "Fukushima's Doses Tallied," Nature 485, 423 (2012).
[8] G. Brumfiel, "Fukushima: Fallout of Fear," Nature 493, 290 (2013).
[9] H. Beech, "The World's Most Dangerous Room" Time, 21 Aug 14.
[10] J. Hanna, "Japan Lifts 4-Year Evacuation of Fukushima Town," CNN, 5 Sep 15.
[11] M. Yamaguchi, "Evacuation Order Lifted for Town near Japan's Stricken Nuclear Plant; Residents Slow to Return," U.S. News and World Report, 5 Sep 15.
[12] H. Tabuchi, "Japan Premier Wants Shift Away From Nuclear Power," New York Times, 13 Jul 11.
[13] J. Hymans, "After Fukushima: Veto Players and Japanese Nuclear Policy," in Japan: The Precarious Future, ed. by F. Baldwin and A. Allison (New York University Press, 2015), p.110
[14] E. Johnston, "Third Reactor Restart Spurs Fears Over Shaky Kansai Evacuation Plans," Japan Times, 29 Jan 16.
[15] H. Takahashi, The Future of Japan’s Energy Mix," Living Energy, No. 17, 68 (July 2015).
