Today marks the 30th anniversary of the most catastrophic nuclear disaster in history. On April 26, 1986, one of the four reactors at Ukraine’s Chernobyl nuclear plant exploded, spewing radiation into the atmosphere.
The disaster occurred following an “experiment” to determine whether the cooling pump system could function using low reactor power (in the event of an electricity failure). For the experiment, staff lowered additional control rods into the reactor core to reduce output to 20%. But they lowered too many and output dropped rapidly—to the point of almost complete shutdown. To counteract the drop, the staff raised more and more rods until, unexpectedly, power levels surged to 10+ times the normal level! Two explosions followed, rupturing the containment vessel and causing a fire that lasted 9 days.
The explosions released over 5% of the reactor core into the atmosphere, contaminating large swaths of Ukraine, Belarus, Russia, and Scandinavia. Within 3 months, at least 31 people succumbed to acute radiation sickness and over 350,000 fled their homes. Another 4000+ people contracted thyroid cancer in ensuing years. (Going forward, experts believe that long-term radiation exposure will cause 9000 – 93,000 additional cancer deaths).
These horrific effects led to a burst of activity to improve atomic safety. Among other things, the nuclear community created the World Association of Nuclear Operators to review 430 reactors worldwide for problems. The International Atomic Energy Agency “beefed up” its role as UN nuclear watchdog and expanded its safety standards. Moreover, countries signed various international agreements, including the Convention on Nuclear Safety.
These efforts were “critical”. Yet, they have failed to prevent all further nuclear accidents. In March 2011, for example, the second largest nuclear disaster occurred at Japan’s Fukushima-Daiichi power plant. In this case, a massive earthquake off the coast triggered a 13-15 metre tsunami. The waves exceeded the seawall, flooding key buildings and destroying equipment needed to prevent nuclear meltdown.
Such incidents have prompted more and more countries to phase out the use of nuclear energy. These countries include Italy, Belgium, Switzerland, and recently, Germany. Chancellor Angela Merkel explained “After what was… an unimaginable disaster in Fukushima, we have had to reconsider the role of nuclear energy”. The country now plans to close all of its 17 nuclear reactors by 2022.
But despite its risks, nuclear energy has many redeeming qualities. It is energy dense, producing far more energy per unit of mass than any other source. It is cost-competitive thanks to low fuel costs. It provides more reliable base load energy than solar and wind power, which are weather dependent. And unlike fossil fuels, nuclear power generation produces minimal greenhouse gases like carbon dioxide and methane. In the words of Christine Todd Whitman, a former EPA Administrator, nuclear energy is “the country’s largest source of clean-air energy that’s available 24/7” and is “a critical tool in combating climate change“. For these reasons, nuclear energy remains a key part of our energy mix, accounting for 20% of US electricity generation.