Comparative Analysis of Catastrophes in Fukushima and Chernobyl

Georgy Zerkalov
March 20, 2016

Submitted as coursework for PH241, Stanford University, Winter 2016


Fig. 1: International nuclear and radiological event scale. [3] (Source: G. Zerkalov)

The developing world relies heavily on energy. In 2014 total world energy consumption increased by 0.9% to reach 12928.4 million tons of oil equivalent. The production on nuclear energy dropped by 10% in 2011 and 2012 after the catastrophe in Fukushima on March 11, 2011. Nonetheless, the increased production in South Korea, China and France helped to restore the demand for nuclear energy. Thus, global nuclear output grew by 1.8% in 2014 to reach 574 million tons of oil equivalent, which is 4.4% of total energy consumed in the world in 2014. [1] The Fukushima nuclear accident was the second largest after the accident in Chernobyl (Soviet Union) on April 26, 1986. The International Atomic Agency developed the International Nuclear and Radiological Event Scale, which uses a logarithmic scale to represent the severity of different nuclear accidents. Both accidents were ranked at 7, which corresponds to the most severe event on the scale (Fig. 1). [2] The accidents had not only short-term but also severe long-term effects and raised questions regarding the reliability and safety of nuclear plants. This work provides a comparative analysis of the two nuclear disasters.

Chernobyl Accident Background

The Chernobyl disaster occurred in the city of Pripyat on April 25, 1986. During the course of the accident large quantities of fission products were released in the biosphere in addition to the initial heat release, which killed onsite workers. The contamination caused by the emission of the radioactive materials seriously affected the surrounding environment and people who lived in the region. The accident resulted from weaknesses in the reactor design and a number of operator errors that violated the safety procedure of the plant. The reactor had flaws in the design and had to be modernized to avoid serious consequences. The accident happened during an experiment, which should have introduced a new way to generate power sufficient to run the cooling pump during electric blackouts. During the experiment many of the safety signals and valves were turned off. When the experiment failed, there has not been a way to keep the cooling pump running, which caused overheating of the reactant, explosion of its core, emission of large quantities of radioactive materials and ignition of the combustible graphite moderator. [4] The latter promoted the dispersion of radioactive particles by the means of smoke, which was not confined due to the absence of any containment vessel.

Fig. 2: Photo of the Fukushima nuclear power plant after the accident. (Source: Wikimedia Commons)

Fukushima Accident Background

The Fukushima disaster happened at Fukushima Daiichi Nuclear Power plant on March 11, 2011. The main cause of the accident was the loss of the supply of power to the cooling pumps which caused the meltdown of reactors. The power blackout was caused by a strong earthquake (magnitude 9) followed by a series of tsunamis. Shortly after the earthquake, operating reactors 4, 5, and 6 ceased to operate, thus terminating the production of electricity required for their cooling. The diesel generators started to provide power to the cooling systems and operated until the tsunami hit the rooms where they were located, causing them to fail. The secondary emergency pumps run by backup electric batteries stopped working a day after the tsunami hit. The situation gravely worsened when hydrogen-air chemical explosions occurred. The hydrogen was produced from the zirconium fuel cladding-water reaction. Large amounts of radioactive materials spread around with the help of wind, affecting human and livestock industry in the surrounding regions. As seen in Fig. 2, three units suffered severe damage from the explosions.

Comparing the Two Accidents


Despite several detrimental catastrophes that happened in the past on nuclear power plants the world keeps relying on nuclear energy and increases capacities of it production. The comprehensive analysis present in this work addresses causes and consequences of the nuclear accidents in Chernobyl and Fukushima. It is important to thoroughly analyze the lessons learned and implement changes to other currently used power plants to increase their safety and minimize the risk of future catastrophes.

© Georgy Zerkalov. 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.


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[2] Devil's Bargain?: Energy Risks And The Public," U.K. House of Commons, 27 Jun 12.

[3] G. A. M. Webb, R. W. Anderson, and M. J. S. Gaffney, "Classification Of Events With An Off-Site Radiological Impact At The Sellafield Site Between 1950 And 2000, Using The International Nuclear Event Scale," J. Radiol. Prot. 26, 33 (2006).

[4] S. Mukhopadhyay, J. Halligan, and M. Hastak, "Compare And Contrast Major Nuclear Power Plant Disasters: Lessons Learned From The Past," Purdue University, 20 May 14.

[5] E. A. Rezchikov and O. N. Zalomnova, Ecology (Moscow State Industrial University, Moscow, 2012) [Е. А. Резчиков и О. Н. Заломнова, Экология (МГИУ, Москва, 2012)], p. 123.

[6] J. Ahn et al., eds., Reflections On The Fukushima Daiichi Nuclear Accident (Springer, 2015), p. 72.

[7] G. A. Colditz, ed., Encyclopedia Of Cancer And Society (SAGE Publications, 2007).

[8] M. Charles, "Book Review: Health Effects Due To Radiation From The Chernobyl Accident. Annex D Of UNSCEAR 2008: Sources And Effects Of Ionizing Radiation. Volume 2: Effects," J. Radiol. Prot. 31, 275 (2011).